The present invention relates to a method for operating a water circulation system, in particular a piped drinking or service water system.
Operating methods for water circulation systems are known from the prior art in which the water temperature must be kept above or below a predefined temperature in order not to promote the growth of germs. The growth of germs such as Pseudomonas aeruginosa or Legionella is particularly favored in a temperature range of 20 to 50° C. For reasons of hygiene, i.e. to prevent germ growth as much as possible, the water temperature should therefore not be kept in this range. For reasons of convenience, i.e. to be able to quickly achieve a sufficiently high mixed temperature, the hot water temperature is usually kept at 55° C. Since the hot water pipes cannot be perfectly insulated, heat is continuously given off from the pipes to the cooler environment; usually 8 to 10 watts per meter. The greater the temperature difference between the hot water and the environment, the greater the heat loss in the pipes. To keep the hot water temperature at 55° C., it has to be heated continuously, which means that energy is constantly required for heating. Accordingly, the cold water should be kept below 20° C. Since the cold water pipes cannot be perfectly insulated either, the pipes continuously absorb heat from the warmer environment. The greater the temperature difference between the cold water and the environment, the greater the heat absorption of the pipes. In order to keep the water temperature permanently below 20° C. in a cold water system, cooling must be carried out continuously, which means that energy is constantly required for cooling. Furthermore, with today's systems, the hydraulic balancing of the individual circuits must be carried out manually in accordance with the planner's information. If this adjustment is not carried out, which is often the case in practice, the valve of each strand is usually completely or almost completely open, which means that the greatest amount of water circulates in the strand with the shortest connection line to the temperature control unit. Accordingly, this strand is the warmest in a hot water circuit and the coolest in a cold water circuit. The strand with the longest connection line to the temperature control unit is accordingly the coolest in the hot water circuit and the warmest in the cold water circuit. In case of a circuit without hydraulic balancing of the individual strands, the required target temperature can no longer be achieved, which represents a high safety risk.
An object of the present invention is to provide a method for operating a drinking or service water system which is more energy-efficient. The method is also intended to enable automatic hydraulic balancing of the strands of the drinking or service water system.
This object is achieved by a method with the features of claim 1. Further embodiments of the method are defined by the features of further claims.
A method for operating a water circulation system according to the invention comprises the steps of:
Such a method has the advantage that the heat losses can be kept lower, since the heat transfer from the water to the pipe is smaller when the water is still than when the water is flowing. In this way, the amount of heat flowing off into the environment can be reduced, so that less heat energy has to be supplied to the system, which makes the system more energy-efficient. Another advantage is that in a system with several strands, by completely closing the valve of one strand, more water can flow in the other strands. When the water in the first strand has reached the target temperature, the corresponding valve is completely closed, which means that more water is available to the other strands, so that they can reach the target temperature more quickly. With this method, an automatic hydraulic balancing of the individual strands is realized, whereby the target temperature can be reached safely and as quickly as possible in all stands. With these method steps it can be prevented, for example, that the water temperature at a location in the circuit can fall below the permissible value without this being recognizable. If the temperature sensor of a strand is located, for example, in a heating room, the water temperature measured by the sensor corresponds increasingly to the local ambient temperature of the sensor when the valve is completely closed. After installation, a fixed value can be set for the time duration of each strand and the value will not be changed afterwards.
A consumer can be any type of water extraction point, for example a sink, shower, bathtub or the like.
A valve can be any type of valve that can be opened and closed with an actuator, the actuator being controllable by the control unit.
A temperature sensor can be any type of temperature sensor with which the water temperature can be reliably measured in a range from 5 to 60° C. The temperature sensor can be in direct contact with the water to be measured or it can be separate from the water, i.e. it can be arranged on the outside of the corresponding line.
The control unit can be any type of control unit which enables temperatures to be defined, the temperatures detected by the temperature sensor to be compared with the defined temperatures and with which the valve can be controlled on the basis of the comparison, i.e. can be at least partially opened or closed.
For example, a first permissible temperature can be defined as the first temperature and a second permissible temperature can be defined as the second temperature. In a hot water system, the first temperature can be a lower permissible temperature and the second temperature can be a higher permissible temperature. For example, the upper temperature can be 56° C. and the lower temperature 55° C. In a cold water system, the first temperature can be an upper permissible temperature and the second temperature can be a lower permissible temperature. For example, the upper temperature can be 16° C. and the lower temperature 15° C.
In one embodiment, the method comprises the step of:
By recording the temperature profile, not only the actual value but also the change in temperature over time can be determined.
In one embodiment, the method comprises the steps of:
If the second temperature is to be reached as quickly as possible, the valve is opened to the maximum. If a less strong increase in temperature is desired, the valve is only partially opened.
In one embodiment, the method comprises the steps of:
For example, a temperature profile can be assigned to washing hands, showering or taking a bath. Washing hands uses a small amount of water over a short period of time. Taking a shower uses more water over a longer period of time, and taking a bath uses a lot of water over a long period of time. If water is withdrawn at a consumer, water flows from the supply line and from the return line in the direction of this consumer. I.e. the water at the temperature sensor arranged in the strand flows backwards at this moment, i.e. against the direction of flow. Since the backward-flowing water has lingered in the line for a long time and is cooler due to the constant loss of heat, a decrease in temperature can be determined on the temperature sensor during consumption. However, the assignment can only take place when the valve is at least partially open, since only then can the water flow in the corresponding strand against the general direction of flow.
In one embodiment, the method comprises the steps of:
The trigger threshold can be defined as a temperature value or as a temperature difference to the set temperature. The trigger threshold can also be the set temperature. Several different trigger thresholds can be defined.
In one embodiment, the method comprises the steps of:
For example, a period of the day in which only low consumption is to be expected can be provided as the time window. Several time windows can also be distributed over the day. For example, the time windows can be provided between the main consumption times. Usually, the consumption in the morning, at noon and in the evening is higher than in the time in between. Outside of this time window, the valve can be partially or fully open to keep the temperature level high so that the user does not have to wait long for warm or cold water. Usually, the most water is used in the morning, at noon and in the evening.
Accordingly, the time windows can be set in the periods in between. For example, from midnight to 6 a.m., from 9 a.m. to 11 a.m., from 1 p.m. to 6 p.m. and from 8 p.m. to midnight.
In one embodiment, the method comprises the steps of:
With these process steps, the time duration can be adapted to the currently prevailing conditions. The surroundings of the system are, for example, warmer during the day or in summer than at night or in winter. Accordingly, it makes sense to adjust the time periods accordingly.
In one embodiment, the at least one temperature sensor is arranged in the immediate vicinity of the at least one valve. For example, it can be arranged before, immediately before, after or immediately after the valve. Alternatively, the at least one temperature sensor is arranged in the at least one valve, i.e. the temperature sensor is integrated in the valve.
In one embodiment, the water circulation system comprises a temperature sensor on the supply line, in the area of the temperature control unit, with which the supply temperature can be detected. In this way, the temperature difference between the flow temperature and the temperature measured on the strand can be determined, whereby conclusions can be drawn about the heat loss in the supply part of the pipe system. Alternatively or additionally, the water circulation system comprises a temperature sensor in the area of the temperature control unit, with which the return temperature can be detected. Thus, the temperature difference between the strand temperature and the return temperature can be determined, whereby conclusions can be drawn about the heat loss in the return part of the pipe system. The principle is the same in a cold water system, but the heat absorption can be determined.
In one embodiment, the water circulation system comprises two or more strands, each with at least one consumer, at least one valve and at least one temperature sensor, each of the stands comprising its own control unit. In the case of an individual strand control, for example, the valves of all strands are fully open. As soon as the temperature sensor of one strand reaches the second temperature, the corresponding valve is closed, which means that warm water can reach the other strands more quickly. This reduces the heat loss in the strand with the standing water. As soon as the second temperature is measured in all strands, all valves are closed. The heat loss is reduced in all strands. Alternatively, all strand can comprise a common control unit. With a common control unit, for example, rocking effects can be suppressed, which makes the system more stable.
In one embodiment, the water circulation system comprises a pump, a non-return valve and a filter. The pump provides the necessary pressure increase to circulate the water in the system. The non-return valve, for example a check valve, prevents water from flowing back from the temperature control unit into the return line. Alternatively or additionally, a non-return valve can be provided in the supply line and prevent water from flowing back from the system into the public water connection. The filter cleans the water in the circulation system and can be used in the supply line before the temperature control unit or in the system, i.e. be provided in the supply line, the strand or the return line.
In one embodiment, the at least one temperature control unit comprises a heating unit or a cooling unit.
In one embodiment, the water circulation system comprises at least one hot water circulation system with a heating unit and a cold water circulation system with a cooling unit.
The mentioned embodiments of the method can be combined as desired, provided they do not contradict one another.
Embodiments of the current invention are described in more detail in the following with reference to the figures.
These are for illustrative purposes only and are not to be construed as limiting. It shows
In a hot water system, the tap water circulates in the first intervals I1 and the water stands still in the second intervals I2. The strand temperature TS is kept between the first temperature T1 and the second temperature T2. If the temperature sensor of the strand indicates that the measured water has the first temperature T1, the valve 6 is opened at least partially, as a result of which the water temperature in the strand 3 rises. When the strand temperature TS reaches the second temperature T2, the valve 6 is closed. When the valve 6 is closed, the strand temperature TS decreases over time. If it reaches the first temperature T1, the valve is opened again. The more the valve is opened, the faster the second temperature is reached and the shorter the heating interval.
In a cold water system, the tap water circulates in the second intervals I2 and the water stands still in the first intervals I1. As soon as the circulation starts, the strand temperature TS decreases and as soon as the water stands still in the strands, the temperature of the strand water increases.
Several trigger thresholds can also be defined so that the determination is not based solely on time, i.e. based on the length of the intervals. In this way, it can be determined during which time which trigger threshold is exceeded. If only the first trigger threshold is exceeded, this indicates hand washing. If the first trigger threshold is exceeded during a first interval and a second trigger threshold is exceeded during a second interval, the first trigger threshold being smaller than the second and the first interval being longer than the second, this indicates showering. Any number of trigger thresholds and intervals can be combined with one another and compared for an evaluation. The preset strand temperature can also be used as the trigger threshold.
Filing Document | Filing Date | Country | Kind |
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PCT/EP2018/067082 | 6/26/2018 | WO | 00 |