Patent Application
20240247813
The present invention relates to a heated water delivery system. In particular, the invention relates to a heated water delivery system comprising at least two sources for providing heated water.
Systems for providing hot or heated water are very well known, both in commercial and domestic settings, and may comprise a conventional boiler or a combination (or ‘combi’) boiler.
A hot water system utilizing a conventional boiler comprises a hot water tank, in which heated water is stored until it is required for use. An advantage of such a system is that it can meet high demand for hot water as well as providing good water pressure; however, once all of the hot water in the tank has been used, it is necessary to wait for water in the tank to be heated before further hot water can be provided.
Combi boilers are a common alternative to conventional hot water systems and, instead of storing hot water, they instantaneously heat water from a mains water supply when a user turns on a tap. An advantage of combi boilers is that they provide hot water on demand; however, they may struggle to meet high demand if several users are attempting to use the hot water system simultaneously, and water pressure at hot taps or outlets some distance from the boiler may be insufficient.
Storage combi boilers aim to utilize the advantages of conventional and combi boilers by combining both an internal hot water tank and means for heating water on demand. However, such boilers can be more expensive and bigger than combi boilers, and they generally have a smaller hot water tank capacity than those associated with a conventional boiler.
It is known to connect an external water tank to a combi boiler. For example, EP1962025 describes a system comprising a solar thermal water tank, a combi boiler and a thermostatically controlled valve. Depending on the temperature of water delivered from the water tank, the valve-which comprises a three-port valve arrangement-diverts water internally to a thermostatically controlled feed to the2 combi boiler or to a thermostatically controlled water mixer valve. However, the type of valve used in such systems can be expensive as well as being limited to the configuration described in which there are only two sources of hot water.
The heated water delivery system of the present invention aims to alleviate the problems associated with the prior art. In particular, the embodiments of the present invention seek to provide an improved heated water delivery system.
According to a first aspect of the invention there is provided:
A heated water delivery system comprising:
The configuration of the system ensures that when the water from the primary source is no longer sufficiently hot, water instead flows from a secondary source of heated water. The switching from one source to another is determined by the relative pressure drop of the flow paths.
The valve may be disposed downstream of the primary source.
The valve may comprise a thermo-restrictive valve which is reconfigurable between an open state and a restrictive state in dependence on the temperature of the water at the primary source, the thermo-restrictive valve being configured in an open state when heated water from the primary source is above the threshold temperature, and in a restrictive state when the water from the primary source is below the threshold temperature.
The valve is reconfigurable in dependence on the temperature of the water at the outlet of primary source or in dependence on heat conducted or transferred from the primary source. For example, the temperature of the water may be measured by an external sensor to the valve or in dependence on heat transfer from the primary source into the valve by water flow or heat transfer.
The switching means may comprise a flow restrictor disposed within the secondary flow path. Such a flow restrictor may be used to control the pressure drop of water passing along the flow path.
The primary source may comprise a hot water tank. The secondary source may comprise a hot water tank.
The flow restrictor may be a valve, which may be a thermo-restrictive valve.
The secondary source may comprise a combi boiler. The flow restrictor may comprise the combi boiler.
The switching means may comprise a further flow restrictor within the secondary flow path. The further flow restrictor may be a thermo-restrictive valve.
The system may comprise at least one further flow path for communicating water between the system inlet and the system outlet, the at least one further flow path being fluidly coupled in a parallel configuration with the first and second flow path, the further flow path comprising a further source of heated water, the further source comprising a water inlet and a heated water outlet, wherein the switching means further comprises a further valve disposed within the further flow path for delivering heated water from the further source when a temperature of the water from the further source is greater than a threshold temperature.
The further valve may be disposed downstream of the further source.
The further valve may comprise a thermo-restrictive valve which is reconfigurable between an open and a restrictive state in dependence on the temperature of the water from the further source, the thermo-restrictive valve being configured in an open state when heated water from the further source is above the threshold temperature, and in a restrictive state when the water from the further source is below the threshold temperature.
The further valve may be reconfigurable in dependence on the temperature of the water at the outlet of the further source.
The further valve may be reconfigurable in dependence on heat conducted or transferred from the further source.
The switching means may further comprise a flow restrictor within the further flow path. The flow restrictor may be a valve, which may be a thermo-restrictive valve.
The further source may comprise a hot water tank.
The heated water delivered to the system outlet may be preferentially provided by the flow path with the lowest pressure drop of water along the flow path.
The or each flow restrictor may be arranged to set a pressure drop of water passing along the flow path within which the flow restrictor is disposed, relative to another flow path of the system, in order to control delivery of heated water to the system outlet. The heated water delivered to the system outlet may be preferentially provided by the flow path with the lowest pressure drop of water passing along the flow path.
Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:
Referring to
In the first embodiment, the first tank 30 is connected to the system inlet 10 via a first source inlet 31. A first source outlet 32 connects the first tank 30 to a thermo-restrictive valve (or temperature dependent variable flow restrictor) 33; such a valve opens or closes automatically, depending on the temperature of water flowing through it or the temperature of another point of interest of the system. In the illustrated example, the thermo-restrictive valve is a ‘hot-open’ valve. The valve will be in an open or closed (fully restrictive) state depending on the temperature of the water. The valve 33 of the illustrated embodiment has a pre-set threshold temperature below which the valve closes, but it is envisaged that other embodiments may comprise a valve with a temperature selection mechanism that allows a user to select the temperature at which the valve is in an open or in a restrictive state. The valve is contained wholly within the first flow path, such that water from the secondary path does not flow through the valve. While the valve in the illustrated embodiments is placed downstream of the hot water source, the valve may be placed anywhere within the corresponding flow path provided it is wholly within that flow path.
The second tank 40 is connected to the system inlet via a second source inlet 41 and second source outlet 42 connects the second tank 40 to a second flow restrictor 43.
In the embodiment illustrated in
The illustrated embodiment comprises a flow restrictor 43 between the second source outlet 42 and the second conduit 44, and the skilled person will appreciate that there are various ways of restricting the flow of water from a source such as a hot water tank and the invention is not intended to be limited in this regard. For example, the flow restrictor may be located at any point within the secondary flow path, and the flow restrictor may comprise a ball valve, a double-regulating valve or simply a narrower portion of pipework or another obstruction that increases the pressure drop of the flow path. In some embodiments it is not necessary to provide a flow restrictor within the flow path comprising the second (or further) source for supplying hot water; this may be the case where the second source is a combi boiler, which itself may act as or comprise a flow restrictor which increases the pressure drop of the flow path comprising the combi boiler.
In use, the water in the first tank 30 and the second tank 40 is heated by any known means, which may utilise gas, direct electricity, solar thermal or solar photovoltaic panels or biomass. The tanks 30 and 40 may comprise the same type of heating means or may comprise different heating means. For example, one tank may use gas to heat the water and one tank may use solar power.
When water is caused to flow from the system outlet 20 (by, for example, a user turning on a hot tap), water begins to flow through the first path and/or the second path. When the water in the first tank is sufficiently hot, the thermo-restrictive valve 33 is in an open state due to the heat of the water. When the valve 33 is in an open state, the flow restrictor 43 causes the pressure drop of the second path (i.e. via the second tank 40) to be greater than the pressure drop of the first path (i.e. via the first tank 30). As a result, water flows from the first tank 30 to the system outlet 20 in preference to water from the second tank 40.
As hot water from the first tank 30 leaves the system 1 via the system outlet 20, the temperature of the water remaining in the first tank 30 will decrease as the tank refills with cold water from the mains supply via the system inlet 10. As cooler water begins to flow from the first tank 30 and through the thermo-restrictive valve 33, the valve will be caused to move from an open state to a restrictive or closed state; this increases the pressure drop of the first path such that there will be effectively no flow of cold water from the first tank 30 to the outlet. However, it will be noted that where a valve comprises a bypass (as described below), the bypass may allow some flow of cold water through the bypass section of the valve in order to operate correctly. As the closing of the valve 33 causes the pressure drop of the second flow path to become lower than that of the first flow path, water will flow preferentially from the second tank 40 to the system outlet 20.
This automatic switching from the first path to the second path means that the supply of hot water to the system outlet 20 is uninterrupted when water from the first tank 30 cools provided that there is hot water in the second tank 40. The use of a thermo-restrictive valve to vary the pressure drop through the first path, alongside a measured use of a flow restrictor on the second path, allows the source of the water being delivered to the system outlet to be determined by the relative pressure drop of the first and second paths. Specifically, the second path has a pressure drop that is lower than the pressure drop through the first path when the valve is in a restrictive or closed state (i.e. when the first path is in a high pressure drop state) and higher than the pressure drop through the first path when the valve is in an open state (i.e. when the first path is in a low pressure drop state). The pressure drop of the second path is therefore between the high and low pressure drop states of the first path. The selection of hot water source based on the pressure drop of the delivery paths is common to each of the systems disclosed herein. This avoids the need for the use of more complex valves, such as three-way valves, or electronic switching methods.
The invention is not intended to be limited to a particular type of hot-open thermo-restrictive valve, provided that the valve is suitable for limiting the flow of water from a tank when the water cools down. This may be as a result of the water temperature flowing through the valve itself, or by being externally heated by, for example, conducted heat from the tank. Alternatively, the valve may comprise a bypass that always allows some flow of water through valve regardless of temperature to prevent the cold water from becoming trapped behind the valve thereby preventing it from re-opening even when water in the tank is heated up to a sufficient temperature. An example of a suitable thermo-restrictive valve is shown in GB2467044.
The heated water delivery system 1 of the first embodiment has several advantages. For example, if an existing system does not provide enough water storage, it is possibly to add a further tank to the system rather than replacing an existing tank with a bigger tank. This may be a cost-effective solution to increasing the hot water storage capacity of the system, and has the advantage that the second tank may be placed away from the existing tank (if space at the existing tank location is limited), as well as minimising disruption to the existing system. This is because adding more pipework to the system does not alter any of the existing pipework around the original source of heated water, which remains undisturbed. It is possible to keep the original hot water system working throughout almost all of the installation process, which can be convenient if installation takes more than a day. Additionally, if water pressure at the outlet 20 is low because of high demand, water will flow from the second tank even if water in the first flow path from the first tank is still hot (and thus the thermo-restrictive valve remains open).
Referring to
In the second embodiment, similarly to the first embodiment, when the water in the tank 30 is hot, the pressure drop of the first path is lower than pressure drop of the second path, so water flows from the tank 30 to the system outlet 20 in preference to the second path to meet the hot water demand. As with the first embodiment, when the water in the tank 30 cools, the valve moves from an open state to a restrictive or closed state so that the pressure drop of the first path is greater than that of the second path. As such, water begins to flow from and through the combi boiler 50 in preference to the first path, triggering the combi boiler to deliver hot water. This ensures continued delivery of hot water to the system outlet 20 even though flow from the tank 30 is restricted.
There are several advantages of the configuration of the second embodiment. Firstly, it combines the benefits of a hot water tank and a combi boiler, so that when the hot water in the tank 30 has been used, the combi boiler 50 can be used to provide hot water on demand to the system outlet 20.
Another advantage is that the configuration of the second embodiment allows the hot water tank 30 and combi boiler 50 to be placed in different locations within, for instance, a house. This is beneficial in situations where a long run of pipe extends between the combi boiler 50 and a system outlet 20, for example when a combi boiler 50 located at one end of the house supplies hot water to a system outlet at the opposite end of the house, thereby causing the water pressure from the combi boiler 50 at the system outlet 20 to be low. (As mentioned above, there may be a plurality of system outlets 20.) In this case, providing a system in which a hot water tank 30 is located at the opposite end of the house to the combi boiler provides a higher pressure of hot water to the system outlet 20. If the water in the tank 30 goes cold, the thermo-restrictive valve will operate as described above and it will still be possible to access the hot water provided by the combi boiler 50, albeit at a reduced pressure compared to that of the hot water tank 30.
A further advantage of the configuration of the second embodiment is that if there is a high demand for water at the system outlet 20 (for example, because there is demand at a plurality of system outlets 20), low water pressure at the boiler outlet 52 will trigger the combi boiler 50 to deliver hot water even when the water being delivered from the tank 30 is still hot. This leads to both the combi boiler 50 and tank 30 supplying hot water and increased flow at the system outlet 20.
As with the first embodiment, it is possible to retrofit a tank 30 connected to a thermo-restrictive valve to an existing system comprising a combi boiler 40.
It is known to connect multiple sources for supplying hot water and selecting between them using, for example, an electronic switching method or a three-port valve which can be used to divert water internally. However, embodiments of the present invention use the pressure drop of the path through various sources for supplying hot water to select a hot water source. This method of selection means that the proportion of water flowing from each source will be dictated by the pressure drop of each flow path. The flow from the tank will be restricted when water in the tank is tepid so that the tank can be refilled with hot water.
Compared to known methods of linking together sources for supplying hot water, the described mechanical-only linkage between sources leads to a lower number of parts, easier installation and troubleshooting, more options for system design, long component lifetimes and low maintenance. The system can work at any volume capacity, so is suitable for industrial-and commercial-scale systems, as well as for domestic systems.
While the embodiments described above comprise two sources for supplying hot water, other embodiments of the invention comprise a heated water delivery system with more than two sources for suppling hot water to a system outlet by setting pressure drop cascades to create an order or delivery from the multiple sources. This is possible because in heated water delivery systems according to the present invention, a flow restrictor or thermo-restrictive valve may be provided for each additional path associated with a source for supplying hot water. This makes it possible to control the pressure drop in each flow path so that the contribution from each path to the flow of water to the system outlet is determined by the pressure drop difference between the paths rather than providing requiring a more complex valve for selecting switching between the difference sources as is described in the prior art. In such a cascade, it is preferable that the temperature at which each of the valves opens (or closes) is the same, but in some embodiments each valve may open (or close) at a different temperature. As described above, these temperatures may be set at manufacture or selected by a user. When a thermo-restrictive valve closes a flow path because the associated source of hot water can no longer provide water at or above the set temperature, water is forced through the other flow paths in relation to their associated pressure drop.
To set the order of preference of sources of hot water in a cascade, the pressure drop of each flow path will be controlled. Preferably, each flow path will comprise a flow restrictor, which may be a double-regulating or adjustable opening valve, which will allow the pressure drop of each flow path to be controlled. The pressure drop of each flow path will be such that the preferred (first) flow path has the lowest pressure drop, the second flow path has the next lowest pressure drop and so on such that the pressure drop of each subsequent flow path will increase sequentially along the cascade.
In systems comprising a combi boiler or other instantaneous water heater, the combi boiler or instantaneous water heater would preferably be situated at the bottom of the order delivery. This is to ensure that hot water delivery from a tank is preferred, while the combi boiler or instantaneous water heater is able to provide a continuous supply of hot water on demand when the tanks are exhausted of hot water.
In scenarios where each of the sources can provide hot water (and so each of the thermo-restrictive valves is open) but pressure at the outlet is low, every source in the cascade may supply a proportion of water to the flow from the outlet corresponding to the relative pressure drops of each flow path.
In the third embodiment comprising the heated water system 3, illustrated in
In the fourth embodiment, the system 4 also comprises a third flow path and the same components as and operates similarly to the system 3 of the third embodiment. However, in the fourth embodiment the third conduit 64 connects the tank 60 to the system outlet 10 via the first path, at junction 14, which is between the junction 12 and the tank 30.
The skilled person will appreciate that the configuration of heated water delivery systems according to the invention can be adapted in many ways to suit the required system components and the desired layout. The system is suitable for commercial, industrial, and domestic settings.
The skilled person will also appreciate that controlling the delivery of heated fluid to a source based on the relative pressure drop of various pathways can be applied to various systems, such as an engine coolant system.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2300875.8 | Jan 2023 | GB | national |
