Patent Application
20250067470
The present invention relates to an arrangement for heating a liquid. The arrangement additionally serves to heat a gas, for example room air. The liquid is service water, for example.
In the prior art, it is known to produce thermal energy from the combustion of, for example, propane, butane or diesel fuel converted into the gaseous state, or by using electrical current, and to transfer it via a heat exchanger (or: heat transfer means) to a liquid, for example service water (see for example WO 2020/108908 A1). It is also known that such devices also serve as air heaters.
Usually, devices for heating a liquid are operated in the manner of an instantaneous water heater or a boiler. Therefore, either the heated water is dispensed directly after having passed through a heating section. Or water is heated in a container such that the user can remove it when required. From the point of view of a user, an instantaneous water heater is very convenient. However, to provide a high quantity of warm water, a correspondingly high heating power is necessary. If a lower heating power is to be sufficient, a buffer storage tank—as with a boiler—is necessary for the warm water. Documents DE 20 2011 003 668 U1 or DE 89 13 252 U1, for example, describe buffer storage tanks. Such buffer storage tanks (or: liquid containers) however have the disadvantage that the source of heat is usually installed at the bottom, so that a temperature stratification in the storage buffer tank is destroyed by heating. Furthermore, a significant part of the entire volume must be heated before water having the desired temperature is available.
The invention is based on the object to propose a possibility for providing heated liquid which departs from the known principles of instantaneous water heaters and boilers and thus is an alternative to the prior art. Preferably, the possibility should be characterized by the fact that the disadvantages of a boiler are also avoided if only a low heating power is available which is not sufficient for the operation as an instantaneous water heater.
The object is achieved by the invention by an arrangement for heating a liquid, comprising an energy unit, a heat exchanger, a container, and a pump, wherein the energy unit supplies the heat exchanger with thermal energy, wherein the heat exchanger transfers the thermal energy to the liquid, wherein the container receives the liquid, wherein the container has an opening, and wherein the pump is connected to the opening of the container and to the heat exchanger such that the pump delivers liquid from the opening and/or from the heat exchanger.
According to the invention, an arrangement is provided which constitutes a combination of an instantaneous water heater and a boiler. A pump delivers liquid either from the heat exchanger (this would be the instantaneous water heater) or from a container for the liquid (this would be the boiler). If more liquid leaves the heat exchanger than is delivered by the pump, for example in the direction of a fitting as a dispensing point, the liquid enters the container via the opening. If the pump delivers more liquid, it removes liquid from the container via the opening. If the pump delivers as much liquid as leaves the heat exchanger as heated liquid, the opening of the container and thus the container itself are bridged. Therefore, the pump in particular delivers heated water away from the heat exchanger.
In the following, two teachings will be discussed which relate to specific embodiments of the container: on the one hand with two openings, wherein the liquid can exit the container via an opening, and on the other hand a container having a variable liquid volume. Both teachings can be applied to the aforementioned invention. The same also applies to the embodiments discussed below.
According to one embodiment, an additional pump is present, wherein the additional pump delivers liquid to be heated through the heat exchanger, and wherein the opening of the container is arranged between the heat exchanger and the pump. In one of the following embodiments, the additional pump is referred to as cold water pump. The additional pump delivers the liquid through the heat exchanger which is heated by the latter. The delivery rates of the pump and the additional pump are therefore decisive as to whether liquid enters the container or is removed therefrom.
One embodiment provides that a temperature sensor is present for measuring a temperature of the liquid heated by the heat exchanger, and that a control device receives measured values of the temperature sensor and uses them for controlling the additional pump. In this embodiment, the temperature of the heated water is regulated.
One embodiment involves that the pump delivers heated liquid to a mixing section, wherein a cold water path is present which opens onto the mixing section, wherein a mixed temperature sensor is present for measuring a temperature of the liquid in the mixing section, and wherein a control device controls the pump and/or a cold water path pump for delivering the liquid in the cold water path based on measured values of the mixed temperature sensor and a predetermined temperature range. In this embodiment, the heated liquid is cooled down to a predetermined temperature range. This is for example a protection against scalding. For this purpose, the heated liquid is mixed with cold or non-heated liquid in a mixing section. On the basis of the temperature of the liquid in this mixing section, the delivery quantity of at least one pump is regulated: this is either the pump which delivers the heated liquid, or a cold water path pump which delivers the non-heated liquid.
One embodiment provides that an aeration/ventilation valve is present, wherein the aeration/ventilation valve allows air to be removed from the arrangement, wherein a ventilation pump is present for removing air and liquid through a return line, and wherein the return line opens upstream of the aeration/ventilation valve and upstream of the additional pump. In this embodiment, air is removed from the heated liquid via an aeration/ventilation valve, which in this context can be implemented by a pure ventilation valve. Furthermore, a ventilation pump is arranged downstream of the aeration/ventilation valve, which delivers air (or generally gas) and liquid into a return line. Therefore, the air is removed and can therefore not reach the fitting, for example. As the removed liquid is already heated, it is introduced upstream of the suction area of the additional pump. Therefore, the liquid is again delivered through the heat exchanger, and the thermal energy is not lost. Furthermore, the air in this liquid again reaches the aeration/ventilation valve through the heat exchanger.
A further embodiment consists in that a component is located between the aeration/ventilation valve and the ventilation pump and opens when a predetermined pressure difference is exceeded, such that the liquid can flow in the direction of the ventilation pump. Therefore, a sufficient pressure difference must be present between the two sides of the component. This pressure difference can additionally lead to the release of air.
An additional embodiment provides that the aeration/ventilation valve is not only used for ventilation, but also allows air to enter the line system of the arrangement. For this case, it is provided that the additional pump delivers air through the heat exchanger in one delivery direction, and delivers liquid through the heat exchanger in another delivery direction. The air entering from the exterior via the aeration/ventilation valve, which in one embodiment is composed of two separate units, one for aeration and one for ventilation, serves to empty the heat exchanger.
One embodiment provides that a descaling device is present, wherein the descaling device is arranged along the return line so as to add a descaling agent to the liquid delivered by the ventilation pump. In this embodiment, a descaling agent is added to the returned liquid.
According to a first teaching, it is provided that an arrangement for heating a liquid is present, comprising an energy unit, a heat exchanger, and a container, wherein the energy unit supplies the heat exchanger with thermal energy, wherein the heat exchanger transfers the thermal energy to the liquid, wherein the container receives the liquid, wherein the container has at least two openings, and wherein there is a height difference between the two openings, so that a hydrostatic pressure difference is generated.
The arrangement according to the invention comprises at least an energy unit, a heat exchanger, and a container. The heat exchanger transfers the thermal energy produced by the energy unit, for example using electrical current or by the combustion of a fuel-air-mixture, to the liquid so that the latter is heated.
The container receives the liquid. It includes two openings at different heights so that a hydrostatic pressure difference is produced between the two openings. Therefore, one opening is located higher than the other opening in the direction of the gravitational field of the earth. This involves that the liquid admitted via the upper opening displaces the liquid already present in the container through the lower opening. For example, this allows the container to be slowly filled with heated liquid via the upper opening, wherein due to the temperature-related density difference of the liquids, the colder liquid flows off via the lower opening. In contrast thereto, it is for example possible to draw liquid via the upper opening, which can lead to an automatic refilling via the lower opening. Due to the filling and the removal of the liquid via an opening, the respectively contrary operation (i.e. the emptying or filling) can be initiated.
Accordingly, the arrangement is operated during use such that both openings of the container are open, i.e. allow the passage of liquid. In particular, one opening—the upper opening—is connected to the other components, for example via hoses or pipes. The other opening is preferably connected to a cold water tank (for example a fresh water tank of a vehicle or a caravan)—for example also via at least one hose or a pipe.
Therefore, the container along with the openings thereof may be considered as a kind of hose (or pipe) having a larger storage volume. The connection to the surrounding components (i.e. pumps or normal liquid/air lines, etc.) is such that liquid is introduced into this container hose or removed therefrom in both flow directions. The imaginary hose is thus arranged in the gravitational field such that one opening to this larger storage volume is located above the other opening.
If the container is connected to atmospheric pressure via at least one opening, there is the advantage that no safety valve is necessary as is the case with a pressurized container according to the prior art. In the arrangement, for example the lower opening is connected to a tank which is open and thus is at atmospheric pressure. During use, it must preferably be ensured that the lower opening is connected to the tank via a hose or a pipe, and that this hose or pipe opens below the liquid surface of the tank. The end of the hose should thus be submerged. It can thus be prevented that the container is emptied or air flows therein from the bottom, even if it is arranged above the tank.
Due to the type and arrangement of the container and the way how the container is used, there is no air bubble in the container. During normal operation, the container is therefore completely filled with liquid. As there is no air bubble in the container, the volume thereof can accordingly be completely used for the provision of heated liquid, so that a low total volume is thus also possible. If thermal expansion of the liquid occurs, this additional volume is discharged via the lower opening into the cited components, a fresh water tank, for example. Compensating components such as expansion reservoirs equipped with gas cushions are therefore not required.
The outflow of the liquid out of an opening of the container, while the filling takes place via the other opening, leads to the advantage that the energy unit, for example, can be operated continuously. The thermal energy is continuously dissipated via the heat exchanger and the liquid, even if the liquid in the container is already fully heated. Therefore, the energy unit needs to be switched on and off less frequently, so that, for example, the energy input during starting or the risk of a generally disadvantageous starting operation is avoided. A waiting time, for example, which may be required before the energy unit can be restarted, is also eliminated. For example, less flushing operations of the combustion chamber are required to prepare the energy unit. This is for example a clear advantage if the energy unit burns a fuel such as diesel fuel, for example, to generate thermal energy. It is also particularly advantageous to be able to operate the burner for a specific minimum combustion time, even if the container is already completely filled with heated liquid. This reduction or avoidance of numerous start/stop operations of the energy unit involving waiting times enables a high availability of hot water with a significantly smaller container volume.
In one variant, the energy unit, the heat exchanger and the container belong to a heating device which serves to heat the liquid and which is connected to further components to generally form an arrangement (an alternative designation is system). The arrangement would thus be the device plus further components in the periphery around the device. In one embodiment, the device therefore has appropriate interfaces to connect to the further components. In one embodiment, a further component is for example an additional container which increases the storage volume of the container. From a functional point of view, the combination of a container and an additional container may be considered as a unit.
Preferably, a control device is additionally provided, in which setpoint values are stored or may be stored, which receives measured values, and which controls components of the heating device and/or the arrangement based on the setpoint values and the measured values. Control is here generally understood as an intervention on another unit with respect to the settings or the mode of operation thereof. Control thus specifies what this unit does and to which extent. The term control can therefore include both control in the narrow sense and regulation.
According to a second teaching, it is provided that the arrangement for heating a liquid is equipped with an energy unit, a heat exchanger, a container, and a control device, wherein the energy unit supplies the heat exchanger with thermal energy, wherein the heat exchanger transfers the thermal energy to the liquid, wherein the container receives the liquid, wherein the container has an opening, and wherein the container has a variable liquid volume. In this alternative teaching of the invention, the container preferably has only one opening into which the liquid is introduced or from which the liquid is removed, and which is connected to further components of the arrangement. Such an opening is to be separated from a passage, for example, through which the liquid can flow from the proper container to an additional container or an additional tank. Such an additional tank only increases the internal volume of the overall container arrangement composed of the container and the additional tank. Furthermore, the container has a variable liquid volume. The container can thus expand and contract in the manner of a bladder, so that the amount of liquid which can be received can be between a minimum and a maximum value.
In one embodiment, the container is supplemented by an additional container or an additional tank. The combination of a container and an additional tank has only one opening to the other components of the arrangement or the periphery around the arrangement. Openings may be provided between the container and the additional tank, through which the liquid however flows only within the combination of these two components.
The two teachings according to the invention have in common that the containers are each used so as to contain only the liquid and no air. This is achieved—in the first teaching—by the two openings in the container through which the liquid passes or—in the second teaching—by the variable ability of the container to receive different amounts of liquid.
According to one embodiment of the second teaching of the invention, it is provided that the arrangement is configured in accordance with one of the variants mentioned above or described below. The embodiments also apply accordingly to the arrangement according to the first teaching.
According to the aforementioned second teaching, the container has only one opening, but has a variable liquid volume. As with the container having two openings—some of the subsequent embodiments also apply accordingly to this container, which has a variable liquid volume, for example.
According to one embodiment, the container is at least partially made of plastic. The use of plastic is possible as the container—apart from the generally negligible hydrostatic pressure—does not have to withstand an internal pressure. The material used is characterized by a low weight and by the possibility of being designed in almost any way. Furthermore, the embodiment is generally cost-effective. A plastic or a type of plastic is also used, for example, in the container having the variable liquid volume.
One embodiment provides that the container has the smallest possible volume. This reduction is possible as it is not necessary to store a large amount of heated liquid, and instead, any demand for heated liquid exceeding the volume of the container is met directly by heating additional liquid using the heat exchanger. Reasons for a small container volume include, for example, the following:
In connection with the design of the scalding protection—discussed below—for example by controlling the hot water pump or the cold water path pump, it is possible to store liquid at a high temperature in the container.
If the energy constantly supplied to the heat exchanger is dissipated via a constantly high temperature difference of the liquid delivered therethrough, there is a constantly small volume flow of heated liquid into the container. Such a low flow velocity ensures that a temperature stratification in the container is hardly disturbed.
As the container—having the two openings according to the first teaching—is in pressure equalization with the atmosphere via an opening and no internal overpressure can build up therein, for example when the liquid is heated, no gas bubble is required to limit the pressure.
If there is no air bubble, the stratification is improved as turbulences are avoided.
The container volume is only dimensioned according to the requirements of the hot water demand and does not have to include any additional volume to meet the requirements with regard to a firing in the energy unit as a heat sink (for example due to minimum operating times or waiting times).
According to one embodiment, the container is configured such that a substantially complete emptying with respect to the liquid is possible. Among other things, this serves hygiene purposes. Therefore, no liquid remains in which germs form if it is not used for a longer period of time, for example. A residual emptying is also advantageous if a decalcification or any other chemical cleaning of the arrangement is to be carried out.
According to one embodiment, the container is connected or adapted to be connected to a fresh water tank via an opening. The fresh water tank belongs for example to a vehicle, a caravan or a mobile home, or to a boat in which the arrangement is installed as a system. The liquid—i.e. the water—which is to be heated is preferably removed from the fresh water tank. If the opening of the container via which the liquid—heated at least during operation of the system—leaves the container is connected to the fresh water tank, an active heating of the fresh water tank is possible, and the risk of frost for the fresh water tank can thus be counteracted.
One configuration consists in that a pump for delivering the liquid through the heat exchanger is assigned to the heat exchanger, wherein a temperature sensor is present for measuring a temperature of the liquid delivered through the heat exchanger, and wherein the control device receives measured values of the temperature sensor and uses them for controlling the pump. In this embodiment, a regulation takes place such that the heated liquid has a predetermined desired temperature. To this end, the temperature of the liquid downstream of the heat exchanger is measured. The pump is then controlled based on this actual value so that the delivered amount of liquid is adjusted. In one of the following embodiments, the pump is for example a cold water pump connected to a cold water tank, for example a vehicle-side fresh water tank. By regulating the temperature of the heated liquid, the advantage is achieved that the volume of the container can in this way be used in an optimum manner to store liquid at a constantly high temperature, more specifically irrespective of the temperature of the cold liquid or the thermal energy supplied to the heat exchanger, i.e. the degree of heating which the heat exchanger can provide based on this energy supply.
One embodiment consists in that a pump is present, that the pump is connected to one of the two openings of the container and to the heat exchanger, and that if the pump removes liquid from the container via the one opening, liquid flows into the container via the other opening. In this embodiment, a pump is present which is adapted to deliver liquid from the heat exchanger and/or from an opening of the container. It thus moves liquid heated by the heat exchanger and/or liquid present in the container for example towards a fitting via which the liquid can be drawn from the system. If the liquid is now drawn from the container via one of the two openings, liquid is refilled via the other one of the two openings, more specifically to the same extent. The container is thus not emptied, but remains filled. In one embodiment, the liquid flowing in via the other opening is cold water and in particular not liquid heated by the heat exchanger. In one embodiment, the opening via which the pump removes the liquid from the container, is the upper opening.
In one embodiment, in particular for the arrangement according to the second teaching with the variable liquid volume, it is provided that a pump is present, that the pump is connected to the opening of the container and to the heat exchanger, and that if the pump draws liquid from the container via the opening, the liquid volume of the container is reduced. Therefore, the container for example contracts when liquid is removed therefrom.
In one of the following embodiments, the pump for delivering the liquid from the heat exchanger and the container is referred to as hot water pump, for example.
In one embodiment, a pump draws heated liquid from the container or pumps liquid which has been heated directly by the heat exchanger. If in this embodiment, heated liquid is drawn from the container over a period of time such that no more heated liquid is present therein, i.e. the usable thermal capacity thereof is exhausted, the pump (for example the hot water pump according to one embodiment) primarily delivers liquid directly from the heat exchanger, which thus reaches the outlet of the arrangement, i.e. a fitting, for example. Therefore, the function of the instantaneous water heater is helpful in this case, so that in particular no sudden change from tempered to cold liquid occurs as is possible with boilers.
According to one embodiment, it is provided that an aeration/ventilation valve is present and that the aeration/ventilation valve allows air to be fed into the arrangement or gas to be discharged from the arrangement depending on the case of application. In this component, gas (e.g. air) is discharged from the arrangement or air (in particular ambient air from the area around the arrangement) is supplied via a valve or a valve arrangement. The discharge of air also relates to gas which is released from the liquid when it is heated—for example due to a reduced solubility. The supply of air allows at least parts of the arrangement to be emptied or compressed until empty.
In one configuration, the aeration/ventilation valve is an individual component which fulfills the dual function. In an alternative embodiment, there are two separate components which are considered as one functional unit.
One embodiment provides that an aeration/ventilation valve is present, that a ventilation pump is present for evacuating gas and liquid, and that a return line is arranged so as to open upstream of the aeration/ventilation valve and upstream of a pump which delivers the liquid through the heat exchanger. When heating the liquid, gases or air, for example, dissolved in the liquid can escape. An aeration/ventilation valve is present to prevent this air from reaching a fitting or to prevent the air from entering the container. The aeration/ventilation valve is preferably connected to the line in which the liquid heated by the heat exchanger is guided. Furthermore, a ventilation pump is present which can remove air and liquid. In one embodiment, the ventilation pump is arranged downstream of the aeration/ventilation valve. Due to the ventilation pump, liquid which has already passed through the aeration/ventilation valve is thus also removed. The liquid and thus also the air are guided through a return line which opens upstream of a pump and upstream of the aerating/ventilation pump. The pump delivers liquid through the heat exchanger. This returned liquid therefore again passes the aeration/ventilation valve to evacuate additional air, if necessary. The ventilating effect is thus increased. In the embodiment, only the ventilating character in the aeration/ventilation valve is therefore relevant, so that in one configuration, the aeration/ventilation valve can in particular be reduced to a pure ventilation valve. Furthermore, the returned liquid is again guided through the heat exchanger to thus take the same path as the liquid to be heated and not returned. Therefore, the already transferred thermal energy is not lost but transferred to the liquid to be heated.
In one embodiment, the ventilation pump is also connected to an opening of the container, so that ventilation of the container is thus also possible.
In one embodiment, the function of the aeration/ventilation valve is distributed between two separate valves: one valve is used for ventilation so that air escaping from the heated liquid is evacuated from the arrangement. A further valve is used for aeration, to empty the heat exchanger through the air from the environment. Alternatively, one valve fulfills both functions—as already mentioned above.
In one embodiment, the ventilation pump is not operated continuously, but intermittently. Studies have shown that due to the operation of the pump interrupted by pauses, it is possible to increase the amount of air which can be discharged without the amount of liquid discharged during pumping increasing to the same extent. It is therefore possible to discharge considerably more gas.
According to a further embodiment, the return line opens relative to a supply line of a pump which delivers liquid to be heated to the heat exchanger. The opening area and the effective pump capacities of the ventilation pump and the pump are adapted to each other such that the returned liquid is delivered substantially more strongly in the direction of the heat exchanger by said pump than the ventilation pump introduces the liquid into the supply line. In other words: the ventilation pump introduces the returned liquid into the return line up to the supply line so that the pump in question takes over the further delivery. In one embodiment, the ventilation pump is configured such that, at least for a short time (this is associated with an intermittent operation of the pump), it delivers more than the pump for delivering the liquid to be heated. Due to the intermittent operation, the returned liquid does not reach an end of the supply line into which the ventilation pump delivers liquid and gas or air, but only in this direction. Therefore, a “reservoir” of heated liquid is advantageously created, from which the pump again removes liquid when delivering the liquid to be heated. This possibility for the pump is based on the fact that the return line opens upstream of the cold water pump. As shown in studies, the short-term high pump capacity of the ventilation pump is advantageous to entrain gas bubbles. In one of the following embodiments, the pump for delivering the liquid to be heated is referred to as cold water pump.
One configuration consists in that a component is located between the aeration/ventilation valve and the ventilation pump and opens only when a predetermined pressure difference is exceeded, such that the liquid can flow in one direction. The flow direction is away from the heat exchanger or towards the container. Therefore, the component does not allow the liquid to flow in one direction unless a certain pressure difference is given. This component ensures that the container does not fill with air via the aeration/ventilation valve due to the hydrostatic negative pressure at the upper end thereof caused by the height and arrangement thereof, and that the heated water escapes via the lower end of the container. This in particular also applies in an embodiment in which the container is arranged above the cold water tank. The pressure drop in the liquid caused by the flow through this component causes further gas to escape from the liquid, which can be evacuated via the ventilation pump.
One configuration provides that air can also be introduced into the arrangement via a component which is preferably the aeration/ventilation valve, and that a pump (in one embodiment, this is the cold water pump, for example) is present which delivers air introduced via this component through the heat exchanger. This embodiment—preferably in conjunction with the component mentioned above which opens only when there is a pressure difference—allows the heat exchanger to be emptied without simultaneously emptying the container. This is relevant, for example, when the heat exchanger is intended to heat air, for example room air, in addition to the liquid. In this case, draining can prevent the liquid in the heat exchanger from heating and evaporating during the heating of the air. The air introduced is in particular ambient air from the room outside the arrangement. In one embodiment, the pump is operated until the heat exchanger is empty.
The aforementioned component for introducing the air is for example implemented as follows: a ball is present which has a lower density than the heated liquid, for example water, and which is pressed upwards against a seal by the liquid. As a result, the ball (or an appropriately shaped floating body) closes an opening within the seal to the atmosphere. If there is no liquid below the ball, in particular because it is pumped out, the ball falls down due to gravity, and the opening is no longer closed. Air can therefore flow in.
One embodiment consists in that the pump delivers the air through the heat exchanger in one direction and the liquid through the heat exchanger in another direction. In this embodiment, a pump (for example the cold water pump) is provided which is adapted to deliver two different media (liquid and air) in two different directions. Alternatively, a pump is respectively provided for each medium and each direction.
One embodiment provides that a pump delivers the heated liquid to a mixing section, that a cold water path is present which opens onto the mixing section, and that a mixed temperature sensor is present for measuring a temperature of the liquid in the mixing section. In this embodiment, the temperature of the heated liquid which thus has been heated by the passage through the heat exchanger, is reduced to a predeterminable mixed temperature. To this end, the heated liquid is mixed with cold, i.e. unheated liquid in the mixing section. A temperature sensor is present for setting the temperature of the liquid in the mixing section. The temperature regulation (for example by adjusting the delivery rate of at least one pump which delivers heated/hot or cold liquid to the mixing section) in the mixing section causes the output of liquid at a constant temperature at the fitting, for example. In one embodiment, both the temperature of the heated liquid (for example by the regulation of the cold water pump), and the temperature of the mixed temperature are regulated. In one of the described embodiments, the pump delivering the heated liquid is referred to as hot water pump. In one embodiment, tempering the liquid in the mixing section allows the liquid in the heat exchanger to be first heated to a sufficiently high temperature, for example to kill germs, and still prevents scalding, for example at a water tap or a shower head. In one embodiment, electronic components which serve to regulate the mixing are configured in a redundant manner for this scaling protection to increase the level of safety. As already indicated, the regulation of the temperature of the heated liquid also has the advantage that the volume of the container can thus be used in an optimum manner to store liquid at constantly high temperature—irrespective of the temperature of the cold liquid or the thermal energy supplied to the heat exchanger.
In one embodiment, both the amount of heated liquid which is delivered to the mixing section, and the delivered amount of cold liquid which reaches the mixing section are regulated. In one embodiment, the cold liquid for example from the cold water tank from which the liquid to be heated is taken, is delivered through a cold water path pump. In one embodiment, the last-mentioned pump is furthermore the vehicle pump of the vehicle in which the arrangement is installed.
In one embodiment, it is provided that the control device controls the pump and/or the cold water path pump for delivering the liquid in the cold water path based on measured values of the mixed temperature sensor such that the temperature of the liquid in the mixing section is substantially within a predetermined temperature range at different pressure ratios in the mixing section and/or in the area of the pump or the cold water path pump and/or at different flow rates of the liquid in the mixing section and/or in the area of the pump or the cold water path pump. Throughout the specification, the control of a pump preferably relates to the delivery rate thereof. The temperature range is preferably a tolerance range about a setpoint value. In other words, the temperature sensor measuring the temperature of the liquid in the mixing section allows regulation of the temperature of the liquid which is output, for example, as warm liquid or specifically as warm water via a fitting. The temperature is maintained substantially constant, and this preferably irrespective of the pressure ratios and preferably also irrespective of the flow rates occurring in the arrangement. In one embodiment, the flow rate refers to the flow rate in the mixing section and thus also to the amount removed from the arrangement via a fitting.
In one embodiment, the pump which delivers the heated liquid to the mixing section, is activated when a removal of warm liquid occurs at a fitting, for example. In one embodiment, this activation can be realized via electrical contacts at the withdrawal fitting. In an alternative embodiment, the removal is detected via a decreasing system pressure, for example my means of a pressure switch. In both variants, the signal for the removal of warm liquid can also be used to control a pump (this is for example the cold water pump) for delivering cold liquid or liquid to be heated.
According to one embodiment, two pumps deliver liquid to a mixing section, the two pumps being active simultaneously. Preferably, one pump delivers heated liquid, and the other pump delivers cold liquid to the mixing section. It is then provided that both pumps are generally or always active. For example, it is thus prevented that only cold or only heated liquid reaches a fitting. In one embodiment, the two pumps are the hot water pump and the cold water path pump.
One embodiment consists in that one component for introducing air into the arrangement is present, and that a pump is present, which introduces air introduced via the component into the container via one of the two openings, so that the liquid exits the container via the other opening. This embodiment allows the liquid container to be emptied or ventilated.
In the embodiment, air is introduced into the container for emptying. In one embodiment, the component for introducing the air, which is for example room air from the surroundings around the arrangement or in particular around the liquid system, functions like an overflow valve. In one of the embodiments described, the component is for example referred to as branching non-return valve. The component preferably allows a fluid (here the air) to flow only in one direction (namely inwards) and preferably only when a specific pressure difference is reached. The required minimum pressure difference prevents the container from emptying automatically due the hydrostatic negative pressure given by the two openings at difference heights, as a result of air flowing into the container via the aforementioned component for introducing air. Only the described pump which in one embodiment runs in the reverse direction for this purpose, provides the necessary pressure difference. In one embodiment, this pump is the hot water pump.
In one embodiment, the introduction of air into the container preferably occurs via that opening via which heated liquid is introduced into the container. In one embodiment, in respectively different operating states, heated liquid and air are thus introduced into the container and heated liquid is removed via an opening. If air enters the container via one opening, the liquid flows out of the container via the other opening.
In a supplementary embodiment, the pump is the one which delivers the heated liquid away from the heat exchanger or out of the container. This is the hot water pump, for example.
According to one embodiment, a pump is present which is connected to one of the two openings of the container and to the heat exchanger such that the pump delivers liquid from the opening and from the heat exchanger. In the appropriate embodiment for the second teaching, the pump is connected to the opening of the container and to the heat exchanger such that the pump delivers liquid from the opening and from the heat exchanger.
In a further embodiment, the pump is connected to a hose or a pipe which opens onto the opening and the heat exchanger. When the pump thus pumps liquid from this hose or the pipe, liquid from the container and/or the heat exchanger reaches the pump and thus that part of the arrangement which adjoins the pump. If a corresponding amount of liquid is heated by the heat exchanger, the function of an instantaneous water heater can be implemented. If this amount of liquid of the heat exchanger is not sufficient to meet the current demand, liquid is additionally or alternatively taken from the container. For this case, the function of a boiler is achieved. Due to the direct connection between the pump—which may accordingly also be referred to as hot water pump in one embodiment—and the heat exchanger and the associated instantaneous water heater function, draining of heated liquid is possible when the heating is started. The heating is the process in which the heat exchanger obtains thermal energy from the energy unit.
In one embodiment, the two aforementioned embodiments are combined in that only one pump is used for both purposes. According to the embodiment, it is provided that the pump delivers liquid from the container opening and the heat exchanger in one delivery direction and delivers the air into the container in another delivery direction. This one pump thus delivers air and liquid in two different directions. In the one direction, it delivers heated liquid to a fitting, for example. In the other direction, it delivers air to the container, which is thus emptied.
One embodiment consists in that two pumps are provided, that one pump of the two pumps delivers liquid to be heated to the heat exchanger, and that the other pump of the two pumps is arranged downstream of the heat exchanger and delivers air and liquid. In this embodiment, two pumps are provided, one upstream and one downstream of the heat exchanger. The pumps thus deliver liquid to be heated (or cold liquid) or heated (or hot) liquid. In one embodiment, the upstream pump is referred to as cold water pump. In one embodiment, the first mentioned pump which is arranged upstream of the heat exchanger in one variant is configured such that it can deliver air and liquid. The downstream pump is configured so as to deliver not only liquid, but also air. This air is that air which escapes from the liquid during heating of the liquid. The downstream pump thus allows the line downstream of the heat exchanger to be ventilated. In one embodiment, the downstream pump is configured as a ventilation pump. In an alternative embodiment, this is the hot water pump.
A further embodiment provides that the other pump—i.e. the downstream pump—delivers air and liquid intermittently. This pump—which is preferably the aforementioned ventilation pump—is thus not operated permanently, but only in certain time periods with a predeterminable duration and at predeterminable time intervals. This is in contrast to the upstream pump (for example the cold water pump) which runs continuously during operation, i.e. during the heating phase of the liquid.
According to one embodiment, the container has a variable internal volume. In this embodiment, the container is not a rigid component having a fixed internal volume, rather, the internal volume thereof is variable. The container is thus for example designed as a bladder around which a supporting structure, for example a grid is arranged. The variable internal volume is implemented not only in the container having one opening for the arrangement according to the first teaching, but in one embodiment also in the container having two openings for the arrangement according to the first teaching.
In one embodiment, two pumps are provided, wherein one pump delivers the liquid through the heat exchanger and the other pump delivers the liquid from the heat exchanger and the liquid from the container, for example in the direction of a fitting, and wherein an opening of the container is arranged between the two pumps. The arrangement of the connecting points of the two pumps (one behind the other) and the arrangement of the container opening (therebetween) ensure that the container automatically equalizes the difference of the two pump delivery rates. If the upstream pump delivers more than the downstream pump, the heated liquid enters the container through the opening arranged between the two pumps. If in the other case the downstream pump delivers more liquid than the upstream pump, heated liquid is removed from the container via the opening. This also clearly shows the dual function of the upper opening of the container as an inlet into and an outlet out of the container. The opening of the container is either that opening which is located higher than the other opening in the gravitational field of the earth with regard to the first teaching, or is the only opening which is directly connected to the components for delivering the liquid with regard to the second teaching. If the delivery rates of both pumps are identical, the container is virtually bridged, and the function of an instantaneous water heater is achieved. In one embodiment, the upstream pump is the cold water pump. In an alternative or supplementary embodiment, the downstream pump is the hot water pump.
In one embodiment, the upstream pump is located upstream of the heat exchanger, which is in turn followed by the opening of the container and then the downstream pump. The fact that the opening is located between the heat exchanger and the downstream pump therefore applies to this constellation.
In one embodiment, when the downstream pump (which is the hot water pump, for example) is started, the supply of thermal energy to the heat exchanger and the upstream pump (correspondingly the cold water pump) is also started.
In one embodiment, at least one of the pumps used in the arrangement has a sufficiently high nominal delivery quantity such that only a reduced delivery rate is required during normal operation. This reduces the noise generation during pumping.
According to a further embodiment, it is provided that an additional tank for storing the liquid is additionally provided, and that the additional tank is arranged upstream, downstream or adjacent to the container with respect to a filling with the liquid. In this embodiment, the storage volume of the container or generally of the arrangement is increased by an additional tank. The container and the additional tank can be connected “in series” or “in parallel” depending on the embodiment. If the container includes two openings and thus also the outlet, the liquid flows into the additional tank via the outlet, and from there into a fresh water tank or a gray water tank depending on the embodiment. In this embodiment, the additional tank is thus arranged downstream of the container. Alternatively, the container and the additional tank are connected to the same pipeline which for example originates from the heat exchanger and leads in the direction of the fitting or the hot water pump. In this case, the container and the additional tank are arranged next to each other or in parallel. In one embodiment, the additional tank is designed as a retrofit variant, which can be subsequently connected to an already installed container. The additional tank is for example made of a plastic and for example connected adjacent to or below the container. If the additional tank has its own outlet, the latter is preferably provided with a temperature sensor—similarly to the temperature sensor behind the outlet of the container.
In one embodiment, the container and/or the additional tank are/is spatially separated from the other component parts of the arrangement. For example, the container and/or the additional tank are/is located in the space of a vehicle, while the other component parts are located below the vehicle floor (so-called underfloor). Alternatively, the container is located in the vehicle and the additional tank outside thereof.
One embodiment provides that a descaling device is present and that the descaling device is arranged between a first pump which delivers the liquid to be heated to the heat exchanger, and a second pump which delivers gas and liquid in the direction of the first pump, so as to add a descaling agent to the liquid delivered by the second pump. The descaling device for example receives a descaling agent and releases it to the liquid. The second pump is for example the ventilation pump and primarily serves to pump air from the heated liquid. Heated liquid then enters a return path. As the liquid is heated, the descaling is promoted. The return path preferably opens in front of an suction nozzle of the first pump, which pumps liquid to be heated, i.e. cold liquid to the heat exchanger and therethrough. The first pump is for example the cold water pump. By delivering the liquid containing the descaling agent in the direction of the first pump, the first pump can pump this liquid enriched by the agent through the heat exchanger and thus descale the latter.
More specifically, there are numerous possibilities for designing and further developing the arrangement according to the invention. For this purpose, reference is made, on the one hand, to the claims which depend on claim 1, and, on the other hand, to the description below of example embodiments in conjunction with the drawing, in which:
The thermal energy for heating is generated by the energy unit 1 by the combustion of a fuel-air mixture and/or by electrical energy, and is transferred to the liquid by the heat exchanger 2. For this purpose, a cold water pump 11 pumps the cold water to be heated—for example from a fresh water tank of a vehicle or another cold water tank—through the heat exchanger 2. The heated water is introduced into a warm water container 3 and flows from there to a fitting 5. The arrangement of the inflow and outflow paths is here purely exemplary.
Cold water is also fed to the fitting 5 through a cold water path 4, a cold water path pump 12 being provided. In one embodiment, the cold water originates from the aforementioned cold water tank. In the embodiment shown, the heated water and the cold water are mixed in a mixing section 30, so that water tempered at a desired temperature reaches the fitting 5.
Furthermore, a control device 6 is provided for the processes in the device, which acts on components of the device or the system described below based on measured values, for example. In one variant, the control device 6 controls the energy unit 1 and thus also the heat exchanger 2 or the heating process. In one variant, this is realized in a time-controlled manner. Alternatively or additionally, the heating operation is started by a user. In one embodiment—not shown—the user initiates the start via a switch or an app functionality, for example.
The system is described below starting from a cold water tank 10 up to the fitting 5. In the application shown here, all supply and discharge lines to or from the cold water tank (for example a fresh water tank of a vehicle or a mobile home etc.) 10 open below the liquid level. Furthermore, the cold water tank 10 is open to the atmosphere, such that it is always at atmospheric pressure.
The water leaves the cold water tank 10 via three paths: on the one hand, it is delivered into a warm water container 3 by a cold water pump 11, and on the other hand, it reaches the fitting 5 directly via the cold water path 4 by means of a cold water path pump 12 which is a vehicle pump, for example, to allow the desired temperature to be set by the user. Furthermore, the water from the cold water tank 10 can flow into the warm water container 3 via the outlet 13 of the container.
Water enters the cold water tank 10 and thus exits the system via the already mentioned outlet 13 from the warm water container 3. The outlet 13 is here located in the bottom of the warm water container 3 and is permanently open. Due to the position of the outlet 13 at a low point in the warm water container 3, the lowest layer of water flows out first, which is in particular the coldest layer of water.
As already indicated, water from the cold water tank 10 can also enter this lower area of the warm water container 3 when the hot water pump 20 is activated—depending on the delivery rates of the pumps 11 and 19. For this purpose, a hose or a pipe connects the outlet 13 to the cold water tank 10, the hose or the pipe opening below the liquid level in the cold water tank 10.
A water outlet temperature sensor 14 which allows the temperature of the discharged water to be measured is located between the outlet 13 and the cold water tank 10. In an alternative embodiment—not shown—the water outlet temperature sensor 14 is integrated into the outlet 13. Assuming that the coldest water flows out and a set temperature for the warm water is specified (see the specification below), it is possible to determine the degree of filling with water having the desired temperature based on the measured temperature. In addition, the measured values of the water outlet temperature sensor 14 allow the heat exchanger 2 or the associated energy unit 1 to be regulated.
First, the path of the water passing via the warm water container 3 is described.
A cold water temperature sensor 15 senses the temperature of the water delivered from the cold water tank 10 by the cold water pump 11. In one embodiment of the system, the cold water temperature sensor 15 allows the smart control of the cold water pump 11 by pilot control and/or predictive regulation. In the embodiment shown here, the cold water pump 11 is self-priming, for example a gear pump, such that it can also fill the suction line thereof with water when it is arranged above the cold water tank 10—as indicated here.
In the embodiment shown, the cold water pump 11 moves the water in a loop through the warm water container 3. The loop serves as a cooling section for protecting the cold water pump 11 in the event that it is operated in the reverse direction (see to this end the description below as to the emptying of the heat exchanger 2). In an alternative embodiment—not shown here—the loop is omitted, and the cold water pump 11 delivers the water directly to the heat exchanger 2.
The water is heated in the heat exchanger 2 by using an electrical heating element as an energy unit 1, for example, or by transferring the thermal energy of flue gas or other gases, for example hot room air, which has been heated via a further heat exchanger—not shown here.
A warm water temperature sensor 16 measuring the temperature of the heated water is present downstream of the heat exchanger 2. The delivery quantity of the cold water pump 11 is regulated (indicated by the dashed line) based on the measured temperature, so that a specified set temperature of the heated water is achieved. If, for example, the water is too hot, the delivery rate is increased. If it is too cold, less water is delivered. In one embodiment, the temperature measurement by the cold water temperature sensor 15 is also included in the regulation.
Regulation is performed by a control device 6—not shown here, but indicated in
In one embodiment, the set temperature of the water to be heated is variable. This makes it possible to reduce limescale deposits in the heat exchanger 2 to be expected under certain circumstances, by reducing the temperature of the water to be heated and to be stored.
In terms of preservation of resources, it is provided in one embodiment that a heating to the highest temperature is only performed when the full nominal warm water capacity is to be retrieved soon, i.e. when the user is going to open the fitting 5 soon. This can be communicated by the user by pressing a button on the control, for example.
For the gas dissolved in the water, which produces bubbles when the water is heated, an aeration/ventilation valve 17 is present which automatically removes air bubbles from the line section downstream of the heat exchanger 2 by establishing a connection to the surroundings. The aeration/ventilation valve 17 is preferably arranged at a high point of the liquid line—like the connecting piece of the ventilation pump 19.
In one embodiment—not shown here—the aeration/ventilation valve 17 is composed of two components which each serve individual functions: one component is for discharging the air (this is realized, for example, in the manner of an automatic rapid bleeder having a float, as common in heating engineering), and one component allows air to enter the system in the event of the mentioned reverse operation of the cold water pump 11. The basic structure is as indicated in
The cold water pump 11 delivers the heated water from the heat exchanger 2 against an overflow valve 18, which, in the embodiment shown, is configured similar to a spring-loaded non-return valve, to a line portion where the water either flows into the warm water container 3 via an inlet 21 or is delivered further in the direction of the fitting 5 by a hot water pump 20. The inlet 21 is located at an upper area of the warm water container 3 such that the warm water also collects in an upper liquid layer and sinks—in the direction of gravity or in the direction of the bottom of the warm water container 3—due to water continuing to flow in or the outflow of the deeper water layers through the outlet 13.
The purpose of the overflow valve 18 is apparent from the following context: the overflow valve 18 is designed so as to remain closed until a certain differential pressure between the two line sides to which it is connected is exceeded. If—as illustrated here—the warm water container 3 is located higher than the cold water tank 10, a low negative pressure is created based on the height of the water column along the warm water container 3. Therefore, if the overflow valve 18 were already opened due to this low pressure difference, the warm water container 3 would be filled with air via the aeration/ventilation valve 17 and in particular via the aerating function thereof. The overflow valve 18 is thus designed or, in the case shown here, the spring is so strong that the overflow valve 18 remains closed even if the hot water pump 20 operates at full load and thus generates a higher negative pressure in the warm water container 3 than would automatically be achieved by the water column alone. Only the delivery pressure of the cold water pump 11 can overcome the spring force or generally open the overflow valve 18 and deliver water to the warm water container 3.
Due to the overflow valve 18, a pressure loss is created in the conveyed water such that further gas can escape from the water in form of bubbles. This gas is dissipated via the ventilation pump 19. The line sections between the overflow valve 18, the hot water pump 20 and the outlet 21 are preferably designed so as to form a high point to which the gas automatically flows in that the inlet/outlet lines thereto rise continuously. The ventilation pump 19 preferably sucks off the gas at this high point.
The ventilation pump 19 acts as an non-return valve, such that in one embodiment—not shown here—two components (one for the pump function and one for the function as a non-return valve) form the ventilation pump 19. This additional function of the ventilation pump 19 is necessary, such that the hot water pump 20 sucks only heated water and no water or gas discharged via the ventilation pump 19. In the example embodiment, the ventilation pump 19 is designed as a diaphragm pump which also fulfills the function of a non-return valve.
In one embodiment, the control device 6 activates the ventilation pump 19 automatically, while thermal energy is supplied to the heat exchanger 2. In a further embodiment, the ventilation pump 19 is operated intermittently to improve the removal of gas and simultaneously to take the smallest possible amount of hot water from the warm water container 3.
As the process of pumping out gas usually involves the pumping out of water, the return line 31 which starts from the ventilation pump 19 opens upstream of the cold water pump 11. The gas is then discharged through the aeration/ventilation valve 17. The water pumped out by the ventilation pump 19 mixes with the water from the cold water tank 10 while it is still in the suction line of the cold water pump 11, and is again guided through the heat exchanger 2. Due to the dissipation of air, no thermal energy is lost.
In one embodiment, the area of supply of the water returned by the ventilation pump 19 upstream of the cold water pump 11 is selected such that the water of the ventilation pump 19 enters the suction line of the cold water tank 10, but does not flow thereinto. In this embodiment, the returned water is thus again moved in the direction of the heat exchanger 2 by the cold water pump 11. The ventilation pump 19 is in particular operated intermittently. This leads to the advantage that a storage reservoir for warm water is formed between the cold water pump 11 and the cold water tank 10.
In one embodiment, the ventilation pump 19 is operated continuously. In an alternative embodiment, the ventilation pump 19 is operated intermittently, i.e. with interruptions. Therefore, the advantage is achieved of promoting the removal of air without discharging too much heater water.
The hot water pump 20 delivers the water in the direction of the fitting 5 and, if necessary, draws water from the warm water container 3 via the inlet 21. Depending on the delivery rate of the cold water pump 11 and the hot water pump 20, this results in the behavior of a boiler (water is taken from the warm water container 3) or of an instantaneous water heater (heated water flows directly to the fitting 5). If water is taken from the warm water container 3 via the upper inlet 21, water is filled from the bottom via the outlet 13 from the cold water tank 10 due to the negative pressure generated by the hot water pump 20. It is thus ensured that no air is present in the warm water container 3.
A branching non-return valve 22—which is also spring-loaded in the embodiment—and a first mixing path-non-return valve 23 are arranged downstream of the hot water pump 20. The branching non-return valve 22 is described below with respect to the emptying of the warm water container 3.
The first mixing path-non-return valve 23 ensures that the heated water moves only in the direction towards a mixing section 30 which opens onto the fitting 5. It also ensures that the cold water path pump 12, irrespective of the outlet pressure thereof, cannot press cold water backwards into the warm water container 3 via the hot water pump 20. This is relevant, for example, in the case—shown here—that the hot water pump is designed as a gear pump without any non-return valve functionality. It furthermore ensures that the pressure in the line system to the fitting 5 is maintained if no water is drawn therefrom. This is important in particular when the cold water path pump 12 is controlled via a pressure switch 26 (as in the illustrated embodiment).
In an alternative embodiment—not shown—a pressure reducer is additionally provided—preferably directly—downstream of the cold water pump 12, which reduces the outlet pressure of the cold water path pump 12 to a pressure level similar to that of the hot water pump 20. The two pumps 12, 20 are thus prevented from disturbing each other during their operation.
The cold water path 4 is now described for the understanding of the mixing section 30. The cold water path pump 12 delivers the water from the cold water tank 10 in the direction of the fitting 5. The cold water directly reaches the fitting 5 and also the mixing section 30 via a branching. A second mixing path-non-return valve 24 is present in the branching line from the cold water path 4 to the mixing section 30 and allows the cold water to flow only in this direction towards the mixing section 30. It is thus ensured that no hot water is guided by the cold water path pump 12 in the direction of the cold water tank 10 or the side of the cold water connection of the mixing fitting 5 in case of a low outlet pressure. This in particular applies when the cold water path pump 12 allows a backflow of the flow medium as is the case for rotary or submersible pumps, for example.
In a further embodiment (not shown), the two mixing path-non-return valves 23 and 24 may be omitted if both pumps 12 and 20 are well adapted to each other with regard to their delivery rates and pressures. This in particular applies if the pumps 12 and 20 are controlled via an electrical switch integrated in the mixing fitting, for example (not shown), rather than by means of a pressure switch 26.
The water heated to a predetermined set temperature and the cold water from the cold water tank 10 thus flow into the mixing section 30. The temperature of the mixed water is detected by a mixed temperature sensor 25. In the embodiment shown, a regulating effect is exerted onto the delivery quantity of the hot water pump 20 based on the measured temperature and a predetermined set mixed temperature. This is carried out with the target to achieve the predetermined set mixed temperature. This is therefore the maximum temperature which the water can have when flowing out of the fitting 5. A scalding protection for the user is thus provided.
In an additional or alternative embodiment, influence is exercised on the delivery quantity of the cold water path pump 12 which is a vehicle pump, for example: when combining the control of both pumps 12, 20, the control of the cold water path pump 12 leads to the advantage for the cases that the hot water pump 20 reaches its performance limit or only slightly cooled water or not so strongly heated water is present in the warm water container 30, and that the setpoint value of the mixed temperature is respectively undershot. Therefore, the amount of water at the fitting 5, for example, is reduced in favor of the constant water temperature.
In one variant, the user can specify the set mixed temperature with which the measured values of the mixed temperature sensor 25 for regulating the hot water pump 20 are to be compared. If the user then sets the fitting 5 only to hot water, he obtains water with the desired set mixed temperature.
In an alternative variant—not shown—the direct connection between the cold water tank 10 and the fitting 5 is omitted. Therefore, there is no manual mixing by the user. This is replaced by the specification of the set mixed temperature by the user and the regulation based on the temperature measured by the mixed temperature sensor 25. For example, if the user wants the water to have a temperature of 38° C., the hot water pump 20 is regulated so as to add the appropriate amount of hot water to the cold water delivered by the cold water path pump 20.
Furthermore, a pressure switch 26 is provided in the cold water path 4. It detects the actuation of the fitting 5 and the resulting pressure drop. The hot water pump 20 and the cold water path pump 12 are started based thereon, so that water is available at the fitting 5. If, in contrast thereto, the cold water path pump 12 is switched off, the hot water pump 20 is also switched off. In one embodiment, the cold water path pump 12 is a submersible pump (or a rotary pump) which is switched on, for example, by a microswitch on the fitting 5, this microswitch thus simultaneously switching the hot water pump 20 on (or off accordingly). If the cold water path pump 12 is designed as a pressure pump (for example as a diaphragm pump), the pressure switch 26 may be part of the pump 12.
The following temperatures in the system are for example relevant: the cold water has a temperature of 13° C. The temperature of the heated water is 80° C. so that germs in the water such as Legionella are avoided. The temperature of the mix of heated water and cold water is 50° C. Therefore, if the user himself mixes a water temperature on the fitting 5, it can in principle be between 13° C. and 50° C. for these exemplary values.
The following is a description of how the system allows the warm water container 3 and the heat exchanger 2 to be drained of water. To this end, the cold water pump 11 and the hot water pump 20 are configured so as to be able to deliver medium in two directions and also two different media (water as a liquid and air as a gas). They are thus self-priming. In one embodiment, the pumps 11, 20 (as illustrated) are configured as gear pumps. So far, use of the forward direction has been described.
To drain the heat exchanger 2 from water, the cold water pump 11 is reversed with respect to the delivery direction thereof. The overflow valve 18 which is located between the heat exchanger 2 and the inlet 21 of the warm water container 3 or the hot water pump 20 closes the line automatically. Therefore, no water can flow back from this side towards the fitting 5.
If the cold water pump 11 delivers in the reverse direction, air from the surroundings flows through the aeration/ventilation valve 17 into the line and in particular through the line section which extends through the heat exchanger 2. The line is thus drained, and the heat exchanger 2 cannot heat any liquid.
Emptying is important, for example, if not only liquid but also room air is to be heated by the heat exchanger 2, and if it is in particular provided that there is a pure air mode in which only room air and no liquid is heated. Furthermore, in the air mode, thermal energy which can be associated with a temperature above the boiling point of water is supplied to and transferred by the heat exchanger 2. The purpose of draining the line in the area of the heat exchanger 2 is to avoid noises or pressure surges when the liquid evaporates. Therefore, the generally cold ambient air flowing in through the aeration/ventilation valve 17 entrains water vapor produced when heat is introduced into the heat exchanger 2, before the aforementioned disturbing phenomena occur.
In this mode of operation, air and water vapor are supplied into the cold water tank 10 for draining the heat exchanger 2, where they can again escape to the environment.
In one embodiment, to reduce the risk of damage to the cold water pump 11 by such a hot vapor/air mixture, the latter can be guided and cooled in a loop through the warm water container 3 before passing the cold water pump 11 (as illustrated). The loop serves as a cooling path for protecting the cold water pump 11.
If the warm water container 3 is to be emptied for the cold season or for a longer period of non-use or for cleaning purposes, for example, the hot water pump 20 is operated in the reverse direction. Furthermore, the cold water pump 11 does not deliver any water, and the ventilation pump 19 is not active, either.
If the hot water pump 20 delivers the water away from the fitting 5 in the direction of the inlet 21 of the warm water container 3, the first mixing path-non-return valve 23 closes, and air from the environment around the arrangement can enter the line via the branching non-return valve 22 and can be delivered by the hot water pump 20 in the direction of the warm water container 3.
The branching non-return valve 22 is configured such that it does not open by the low negative pressure produced in the warm water container 3 due to the difference in height between the outlet 13 or the cold water tank 10 and the inlet 21, but only at an appropriately high negative pressure as produced by the hot water pump 20 on the side of the non-return valve 22 during operation in the reverse direction. In one embodiment, the non-return valve 22 is configured as a spring-loaded non-return valve or as an overflow valve.
The water flows out of the warm water container 3 at the bottom through the outlet 13 and is displaced by the ambient air pumped into the container 3 at the top until the warm water container 3 is empty.
The filling of the heat exchanger 2 is performed in that the cold water pump 11 pumps liquid to the heat exchanger 2—in a self-priming manner—as a result of which air is displaced there and exits the arrangement to the environment via the aeration/ventilation valve 17. For this purpose, the line section between the heat exchanger 2 and the overflow valve 18 is preferably configured and arranged such that the aeration/ventilation valve 17 is located at a high point therebetween.
Two variants for filling the warm water container 3 are described based on the above specification. This is realized via the ventilation pump 19, wherein the cold water pump 11 can be omitted. Alternatively or additionally, the filling is carried out via the hot water pump 20 which is operated while the fitting 5 is open and the cold water path pump 12 is not active. In both cases, water from the cold water tank 10 is sucked into the warm water container 3 via the outlet 13.
The warm water container 3 has a total of two openings: an upper opening 21 and a lower opening 13. In the specification, the upper opening 21 is referred to as inlet insofar as the heated water enters the container 3 via the inlet 21. The opening however also serves as an outlet as the hot water pump 20 can remove the heated water via this opening. The lower opening 13 is referred to as outlet insofar as water flows out via this opening when warm water or air enters the container 3 via the inlet 21. The opening however also serves as an inlet for water from the cold water tank 10, for example when the hot water pump 20 draws water from the container 3 via the inlet 21—which in this case acts as an outlet. Thus, both openings 21, 13 could also each be referred to as inlet/outlet openings.
Depending on the embodiment, the system described here is composed of the components of a device for heating water and peripheral components accordingly connected thereto. In one embodiment, the system (alternative designation: arrangement) is composed of such a device and the cold water tank 10, the connection between the two being realized via an appropriate number of lines (i.e. hoses or pipes). In an alternative embodiment, the device does not include the fitting 5 so that the device is connected to the cold water tank 10 and to the fitting 5 as external components. In an alternative embodiment, the cold water path pump 12 is not part of the device but is a vehicle pump, for example, such as is commonly used in mobile homes. In this embodiment, the device therefore comprises appropriate interfaces for controlling the cold water path pump 12 or for detecting the operating state thereof. Accordingly, the fitting 5 can here also be part of the periphery of the device.
The following is a description of a descaling process which is characterized in that the least possible amount of descaling agent enters the cold water tank 10. The pumps 11, 19, 20 and the heat exchanger 2 are thus reliably descaled.
The ventilation pump 19 and the cold water pump 11 are in operation, the energy unit 1 supplying only little thermal energy to the heat exchanger 2. The delivery quantity of the cold water pump 11 is set such that the cold water temperature sensor 15 measures only the temperature of the water from the cold water tank 10 and not of the returned water. Therefore, no returned water containing descaling agent flows into the cold water tank 10. Furthermore, the water containing the descaling agent is slightly heated, which accelerates the descaling process.
The cold water pump 11 is operated so as to deliver more than the ventilation pump 19 so that water also enters the container 3. To prevent the descaling agent from entering the cold water tank 10 via the outlet 13, the hot water pump 20 is operated when the fitting 5 is open. Additionally, the cold water path pump 12 which is a vehicle pump, for example, is preferably not in operation.
Based on the temperature measurements of the mixed temperature sensor 25, the control device 6 reverses the direction of action in contrast to normal operation by setting a higher delivery quantity of the hot water pump 20 when the temperature measured in the mixing section 30 is above the setpoint value (the delivery quantity would be reduced in normal operation). In addition, a setpoint value is set which is slightly lower than the measured value of the warm water temperature sensor 16. This causes the hot water pump 20 to increase the delivery quantity by increasing its speed. It thus pumps a larger amount of water than warm water enters the container 3. It thus draws fresh water from the cold water tank 10 via the container 3. The outlet 13 of the container 3 thus allows filling from the downstream cold water tank 10. This prevents descaling agent from entering the cold water tank 10.
In one operating mode, it is provided for descaling the container 3 that the hot water pump 20 is not operated or only operated with a low delivery rate such that the heated water containing the descaling agent enters the container 3.
In one variant—not shown—sieves are provided at various points of the line system which collect limescale crumbs before they render components such as valves or pumps unusable.
If the pumps used (hot water pump 20 and cold water pump 11) are gear pumps, the ability thereof to deliver air can be improved by also delivering little water therewith. The water serves quasi as a “sealing means” and reduces internal leakages and backflows of air. The amount of air delivered and the delivery pressure are thus increased. This in turn allows the pumps to be designed smaller or operated quietly as a sufficient amount of air is delivered. This is for example in contrast to a diaphragm pump as may be provided in one variant for implementing the ventilation pump 19.
To this end, the hot water pump 20 is considered first:
The arrangement—not shown here—is such that there is a decline of the liquid line upstream of the inlet of the pump 20. Therefore, if the hot water pump 20 delivers in the reverse direction and thus in the direction of the container 3, it first displaces water which is pushed upwards. The line which is a feed line to the pump 20 in normal operation and is located above the pump 20 against the gravitational field of the earth, usually contains some drops of water which flow back into the pump 20 when it is switched off for a short time. “Sealing agent” is then again present, and it can pump air better again. The hot water pump 20 is therefore operated intermittently for the delivery of air.
In one embodiment—not shown—a pipe thickening is provided above the hot water pump 20 so that sufficient water always runs back or downwards into the pump 20 when the pump 20 is stopped. The thickening is large enough such that the delivered air does not completely entrain the water contained therein.
The use with the cold water pump 11 is furthermore considered:
For the cold water pump 11, one embodiment is provided which is shown in
The cold water pump 11 sucks water from the cold water tank 10 itself and ventilates the heat exchanger 2, which, if necessary, has to be performed each time before water is heated: in the event of a previous aeration of the heat exchanger 2, air enters the cold water tank 10 through the cold water pump 11.
According to the embodiment of
In the arrangement of
This embodiment with the parallel lines allows an elegant way of heating the lines to prevent frost: in the event that the arrangement is not operated or that at least no warm water is produced, the ventilation pump 19 is occasionally operated to guide a low amount of warm water via the return line into the hose connecting the cold water tank 10 to the cold water pump 11 which is not active during these periods. This warm water thus also heats the adjacent hoses or ducts. This process is performed in a temperature- and/or time-controlled manner. Freezing of the hose is thus prevented.
The system comprises a functional block A in which the set temperature of the heated water is regulated.
To this end, the temperature of the water heated after the contact with the heat exchanger is measured, and on this basis, the cold water pump—here by way of example—which delivers the water to be heated through the heat exchanger, is regulated accordingly. The pump delivery quantity is thus regulated continuously, so that water at the desired temperature flows to the inlet of the warm water container or further in the direction of the fitting. The heated water flowing into the warm water container displaces the water which is contained therein and is in particular cold. (As will be discussed below, the arrangement according to the second teaching of the invention causes the container 3 to expand). The cold water flows out of the warm water container, and the warm water container fills with the water which is at the desired temperature and can also be delivered to the fitting. As already mentioned, the pump function can be assumed by the cold water pump, the ventilation pump or the hot water pump.
The functional block B serves to discharge the air dissolved in the water which is released when the water is heated. Furthermore, the air can be removed which is contained, for example, in the still empty warm water container or the still empty heat exchanger prior to an initial filling.
This is intended to prevent air from collecting in the warm water container which would disturb the operation of the hot water pump and furthermore would lead to the admixture of air at the tapping fitting. Air in the container would also have negative effects on the usable thermal capacity of the container.
The air released from the water during heating escapes from the line system via an aeration/ventilation valve. If air remains in the water downstream after the passage through the aeration/ventilation valve, a pressure drop at an overflow valve causes it to escape from the water and to be discharged via a ventilation pump. The air and any water also delivered along therewith due to pumping are reintroduced into the line section for the heating of water upstream of the heat exchanger. The air—now in the undissolved state—thus again reaches the aeration/ventilation valve and is discharged to the environment there. The thermal energy of the water is not lost as the water is recirculated.
Operation of the cold water pump is not necessary for the initial filling of the warm water container. In this case, the air sucked off via the ventilation pump is discharged into the fresh water tank.
In the functional block C, a constant discharge temperature of the water is set which does not exceed a maximum value limit. This block C is present in the arrangement according to both teachings.
In the mixing block C, the heated water and the cold water are mixed such that the water dispensed via the fitting cannot be warmer than a maximum temperature. This prevents a scalding of the user and also provides a comfort function. The maximum temperature is lower than the set temperature which is produced by the heating block A.
To this end, a mixing section is provided into which the heated water is introduced via a hot water pump and the cold water is introduced via a pump. A mixed temperature sensor detects the temperature in the mixing section and regulates the delivery quantity of the heated water based on the measured value. In one embodiment, the mixing block C allows the setting of the temperature with which the water is to be discharged from the fitting, i.e. from the water tap or a shower head, for example. The manual regulation of the temperature by the user is thus omitted. The user only has to enter a setpoint value. In one embodiment, the delivery quantity of the cold water is alternatively or additionally regulated.
In one embodiment, the mixing block C is a separate device which is connected to further components at the periphery via appropriate interfaces—in particular with respect to the transport of liquid.
The functional block D serves to switch on the mixing block C.
If, for example, a pressure switch or a microswitch integrated in the fitting detects that the fitting is open and water flows out, the pumps for the cold water and for the warm water are switched on. Mixing then also takes place through mixing block C. The heated water comes directly from the heat exchanger and/or is removed from the warm water container. After the opening of the fitting, water is immediately available to the user.
The functional container emptying block E serves to empty the warm water container. This applies to the arrangement according to the first teaching. The emptying of the container 3 in an arrangement according to the second teaching is described below.
For emptying, the pump delivering the heated water in the direction of the fitting is operated in the reverse direction. A non-return valve or an overflow valve connected to the ambient air thus opens. The non-return valve allows the air to flow in only one direction and only if there is a certain pressure difference. The pump thus first delivers water present in the line, and then air to the inlet of the warm water container. Pumping also causes the mentioned pressure difference for admitting the air via the non-return valve. In normal operation, the pump removes the water from the warm water container via the inlet. As the pump which is active in the heating block A and delivers the cold and the heated water in the direction of the warm water container there during normal operation, is switched off, no new water flows from there in the direction of the inlet. The ventilation pump is furthermore switched off. The water flows out of the warm water container via the outlet, and the pump operated in the reverse direction empties the warm water container.
It may be necessary to exclude a heating of the water through the heat exchanger. This is the case, for example, if the heat exchanger is to heat air and no water in one mode of operation. Water remaining in the line would evaporate and cause noises. The functional heat exchanger emptying block F is therefore provided. Block F can again be implemented in both teachings.
In this functional block F, the pump delivering the water to be heated is operated in the reverse direction and thus draws back the remaining water from the area of the heat exchanger. This is supported by the aeration/ventilation valve which has already been described in the context of the venting block B and acts as an aerating valve in this case of operation. Therefore, air from the environment enters the line and pushes the remaining water in the direction of the pump operated in the reverse direction.
A further functional block—which is not shown for the sake of clarity—serves to descale the pumps 11, 19 and 20 and the heat exchanger 2. Here, reference is made to the above description of
The warm water container 3 does not have a fixed but a variable liquid volume. This is indicated here by a bladder. The container 3 can thus expand depending on the degree of filling. A supporting structure such as a grid is for example located around the bladder as the actual container 3.
Furthermore, the container 3 has only one opening 21, which can be located at any position and here at the top only by way of example. The container 3 is designed such that no air collects therein when it is filled with liquid. For this purpose, the container 3 is for example designed accordingly to be smooth and free of protrusions or folded areas, etc.
In particular, the air is sucked off at a high point above the opening 21 by the ventilation pump 19 before it can enter the container 3.
The two teachings have in common that the container 3 is completely filled with liquid during the heating operation of the device or arrangement and that there is no air therein. This is achieved here, for example, by the container 3 contracting when liquid is removed instead of cold water flowing in from the cold water tank.
Accordingly, the arrangement in
As the container 3 does not have a second, permanently open opening as in the variant of
When the container 3 has reached its maximum internal volume, no further water can be pumped thereinto by the cold water pump 11. Therefore, either the hot water pump 20 must start to remove water or the cold water pump 11 must be stopped. In the second alternative, the supply of thermal energy to the heat exchanger 2 is also stopped, as the exchanger 2 could otherwise overheat.
The ventilation pump 19 can be used to purposefully and completely empty the container 3—thus for example the bladder. The cold water pump 11 must be switched off therefor. The ventilation pump 19 drains the container 3 and pumps the water back into the fresh water tank 10 via the suction hose of the pump 11.
A fundamental difference between the two arrangements is that in the arrangement according to the second teaching of
Part of the arrangement around the container 3 is shown. The overflow valve 18, the ventilation pump 19 and the hot water pump 20 can be seen above the container 3—not only graphically, but also in relation to the realized geometry. An additional tank 3′ is located downstream of the outlet 13 of the container 3 in flow direction. In particular, the additional tank 3′ is arranged relative to the container 3 such that the hydrostatic pressure in the container 3 remains unchanged. The additional tank 3′ therefore only increases the capacity. Therefore, the container 3 and the additional tank 3′ could also be considered as one unit for receiving the liquid. An outlet opening 13′ of the additional tank 3′ is coupled to the fresh water tank 10. In this embodiment, the container 3 is therefore indirectly connected to the fresh water tank 10.
The variant of the arrangement in
In addition to the water outlet temperature sensor 14, the additional tank 3′ also includes an additional tank temperature sensor 14′, the measured values of which are used to control the arrangement.
In addition, the arrangement is designed such that it is possible to dispense with the operation of the cold water path pump 12. This is desirable, for example, if it is a vehicle pump which is designed as a pressure pump to reduce noise generation.
For this purpose, the fixed water connection 40 is not only connected to the cold water tank 10 via the float valve 41, but there is also a connection upstream of the valve 41 into the cold water path 4. The access opens downstream behind the cold water path pump 12. After the fixed water connection 40 and before the branch to the cold water path 4, there is a first non-return valve which prevents water from being pumped into the water network. A second non-return valve which prevents the cold water tank 10 from being filled backwards via the cold water path pump 12 is arranged downstream of the cold water path pump 12 and upstream of the access from the fixed water connection 40.
Preferably, the float valve 41 is automatically locked when the fixed water connection 40 is not connected to the arrangement. This prevents the cold water path pump 12 from only pumping in a circuit via the float valve 41 when the level in the cold water tank 10 is low, instead of building up pressure at the fitting 5.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2022 000 076.8 | Jan 2022 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/025543 | 11/30/2022 | WO |
