GB2511511A

GB2511511A - Installation and method for controlling the supply of heated water

Info

Publication number: GB2511511A
Application number: GB1303862.5A
Authority: GB
Inventors: Jan Oesterholm Hansen
Original assignee: V United Kingdom Ltd SA
Current assignee: V United Kingdom Ltd SA
Priority date: 2013-03-05
Filing date: 2013-03-05
Publication date: 2014-09-10
Anticipated expiration: 2033-03-05
Also published as: GB201303862D0; GB2511511B

Abstract

A district heating installation for supplying hot water and space heating to a user, comprises an inlet source pipe 1 connected to a hot water source; an outlet source pipe 2 for returning the water received through the inlet source pipe, a heat exchanger 3 receiving hot water from the inlet source pipe 1 and returning it to the outlet source pipe 2, and a heat receiving appliance for supplying space heating, connected in parallel to the heat exchanger 3. A water supply inlet pipe 8 supplies water to be heated by the heat exchanger 3, and a heated water pipe 9 supplies the heated water to a user. A prepayment meter 12 controls the supply of hot water and space heating to a user, by controlling two separate valves: a first valve 19 controlling either primary or secondary flow in the heat exchanger 3 for preventing the supply of heated water in the absence of payment, and a second valve 20 controls operation of the space heating.

Description

Installation and method for controlling the supply of heated water This invention relates to an installation for supplying hot water and space heating to a user and to a method of operating such an installation. The invention is particularly, but not exclusively, concerned with a domestic installation in which the source of heat is a distriot heating or central plant supply of hot water and the heat is used for both water heating and space heating.

In such an installation, heat for a number of separate dwellings is transferred from a centralised location in the form of hot water and each dwelling has its own installation for extracting heat from that water for water heating and spaoe heating. One example of an installation that may be provided at each dwelling is the 5101 Flatstation 7 Series BS.

It may also be desirable to provide a prepayment system for ensuring appropriate payment for aocess to the heat provided as hot water from the centralised location.

Such prepayment systems are already known and operate by controlling the supply of the heated water from the oentralised location to the dwelling. Thus without a payment, the flow of hot water from the centralised location is cut off by closing of a valve in the pipe that enters the dwelling to supply the hot water.

It is an object of the invention to provide an improved installation for supplying hot water and space heating to a user and to provide an improved method of operating such an installation.

According to the invention there is provided an installation for supplying hot water and space heating to a user, the installation comprising: an inlet source pipe for connection to a supply pipe of a source of hot water; an outlet source pipe for returning the water that has entered the installation through the inlet source pipe; a first heat exchanger for receiving hot water from the inlet source pipe and returning it to the outlet source pipe after receiving heat; a heat receiving appliance for supplying space heating, connected in parallel to the first heat exchanger for receiving hot water from the inlet source pipe and returning it to the outlet source pipe after receiving heat; a water supply inlet pipe for connection to a water supply to be heated and including a pipe for supplying water to be heated to one or more conduits passing through the first heat exchanger; a heated water pipe for supplying heated water to a user, the heated water pipe being connected to receive water from the one or more conduits passing through the first heat exchanger; a prepayment meter for controlling the supply of hot water and space heating to a user; wherein the prepayment meter is arranged to control a first valve in a flowpath connected in series with the one or more conduits in the first heat exchanger for preventing the flow through the one or more conduits in the absence of payment, and is alsc arranged to ccntrcl the opening of a second valve operable to control the operation of the space heating.

In the prior arrangements, a single valve is provided to control the flow of hot water from its source, whereas in the present invention two separate valves have to be provided, both being controlled by the prepayment system.

Replacing one control valve with two may seem a retrograde step, but actually we have found that it has significant advantages. Vhen a single valve is used, it has to be designed to cope with the highest pressures that may apply to the source of hot water and, especially in the case of a dwelling situated close to the source, that pressure may be high; also, there is desirably little obstruction to flow when the valve is open; thus a substantial and costly valve is reguired. According to the invention a first valve is provided in the flowpath connected in series with the one or more conduits in the first heat exchanger; closing of this valve does not interfere with flow of water from the hot water source through the first heat exchanger, but does disable extraction of heat via the first heat exchanger.

Because the first valve is not in the flowpath from the hot water source, it does not need to operate in that high pressure regime and therefore a much less substantial and cheaper valve can be provided.

Alsc according to the inventicn a second valve is provided to control the operation of the heat, but that need nct prevent the flow of water from the hot water source through the first heat exchanger and thus again a much less substantial and cheaper valve can be provided.

We have found that the replacement of the single expensive valve of the prior design with two less expensive valves is able to provide a better and more economical installation.

Preferably, the second valve is connected in series with the flowpath through the heat receiving appliance of the hot water from the inlet source pipe; in that case the second valve is preferably connected downstream of the heat receiving appliance in the flowpath through the appliance.

The second valve is preferably connected in a portion of the flowpath that is in parallel with the flowpaths to and from the first heat exchanger. In that case, closing of the second valve does not affect flow of water from the inlet source pipe to the first heat exchanger.

The first valve may be connected downstream of the first heat exchanger in the flowpath connected in series with the one or more conduits passing through the first heat exchanger.

Water received in the first heat exchanger from the inlet source pipe is preferably arranged to pass through a plurality of conduits in proximity to the one or more conduits for water to be heated, for transferring heat from the water passing through the plurality of conduits to the water passing thrcugh the one or more conduits.

The "heat receiving appliance" may be a second heat exchanger to provide indirect space heating. An exemplary arrangement of this kind is described below with reference to the accompanying drawings. Alternatively the "heat receiving appliance" may itself be a heater, for example, a radiator, towel rail, an underfloor heating arrangement or the like connected directly to the inlet and outlet source pipes. Of course there may be more than one heater directly connected and they may be connected in parallel or in series.

In the case where the heat receiving appliance is a second heat exchanger, the installation may further comprise a heating inlet pipe for supplying liquid to be heated to one or more conduits passing through the second heat exchanger; and a heating outlet pipe for supplying heated liguid to one or more space heating appliances, the heating outlet pipe being connected to receive liquid from the one or more conduits passing through the second heat exchanger. Water received in the second heat exchanger from the inlet source pipe is preferably arranged to pass through a plurality of conduits in proximity to the one or more conduits for liquid to be heated, for transferring heat from the water passing through the plurality of conduits to the liquid passing through the one or more conduits.

The liquid that the heating inlet pipe is arranged to supply will typically be water, although other liquids may be used, if desired.

It is within the scope of the invention for the second valve to be in a flowpath connected in series with the one or more conduits in the second heat exchanger for preventing the flow through the one or more conduits in the absence of payment, but it is preferred that the second valve is connected in series with the flowpath through the heat receiving appliance of the hot water from the inlet source pipe.

The installation may further include a pump for pumping liquid through the heating inlet pipe and the heating outlet pipe.

The installation may further include means for measuring the heat taken from the source of hot water. The measuring means may seek to measure the heat taken more accurately, taking account of both the flow rate of water from the inlet source pipe and the temperature of the water, or it may for example merely measure the flow rate to provide a simpler but less accurate measurement. The flow rate may be measured in the inlet source pipe or the Outlet source pipe.

A valve, which may be a thermostatic valve, may be provided for controlling flow of water from the inlet source pipe to the first heat exchanger. Similarly, a valve, which may be a thermostatic valve, may be provided for controlling flow of water from the inlet source pipe to the heat receiving appliance. The thermostatic valves may be provided on the upstream or downstream side of the heat exchanger/appliance.

It should be understood that the installation will usually also comprise other components known per se. For example one or more ball valves may be provided in the various pipes to allow them to be shut off and one or more control units may be provided for controlling the operation of part or all of the installation.

The installation may comprise one or more further heating outlet pipes for supplying heated liguid to one or more space heating appliances may be provided, the one or more further heating outlet pipes being connected to receive liquid from the one or more conduits passing through the second heat exchanger. That allows there to be more than one space heating circuit operating at different temperatures.

As will be understood, an installation according to the invention will typically be connected, together with several others, to a source of hot water. The hot water source may be generated in a wide variety of ways and may even be naturally generated. Accordingly, the present invention further provides a district heating or central plant system comprising means for generating a source of hot water and a multiplicity of installations, each as defined above, connected to the source of hot water.

The present invention still further provides a method of operating an installation as defined above.

Certain features of the invention have been described above only with reference to the apparatus of the invention whilst other features have been described only with referenoe to the method of the invention. It should be understood that a feature described in respect of the apparatus may be represented also in a feature of the method and vice versa.

By way of example, an installation for supplying hot water and space heating to a user will now be described with reference to the accompanying drawings, of which: Fig. 1 is a block diagram of a known installation; and Fig. 2 is a block diagram of an installation embodying the invention.

Referring first to Eig.1, there is shown a known installation for supplying hot water and space heating to a user, the installation being one of, typically, 10 to 100 similar installations that are all connected to a common heat source in a district heating system, with each installation serving a respective dwelling which might be, for example, a two bedroom apartment.

The installation is connected to the hot water source via an inlet source pipe 1 connected to a supply pipe (not shown) of the source and an outlet source pipe 2 connected to a return pipe (not shown) of the source.

A first heat exchanger 3 is connected on one side via a pipe 4 to receive hot water from the inlet source pipe 1 and via a pipe 6 to return water to the outlet source pipe 2.

A second heat exchanger 7 is connected on one side to the inlet source pipe 1 and to the outlet source pipe 2.

Thus it can be seen that the first and second heat exchangers are connected in parallel to the inlet source pipe 1 and the outlet source pipe 2.

The first heat exchanger 3 serves to generate hot water for use in the dwelling. A cold water supply, which may be a mains supply, is connected to a water supply inlet pipe 8 leading to the other side of the first heat exchanger and communicating with conduits in the heat exchanger which in turn lead to an outlet connected to a heated water pipe 9 providing a supply of domestic hot water.

The second heat exchanger 7 serves to heat water in a substantially closed circulation path for space heating. A heating inlet pipe 10 is connected to feed water into the other side of the heat exchanger 7 and through conduits in the heat exchanger, the heated water leaving the other side of the heat exchanger through a heating outlet pipe 11.

A prepayment meter 12 is connected to a valve 13 in the inlet source pipe 1. The valve 13 is positioned upstream of the junction of the inlet source pipe 1 and the pipe 4 leading to the first heat exchanger 3, so that when the valve 13 is closed, there can be no flow through the inlet source pipe 1 and therefore no heat supplied to the first or second heat exchangers 3, 7.

A pump 14 is provided in the heating outlet pipe 11 for pumping water around the substantially closed -10 -circulation path already referred to; that path may pass through a number of separate radiators or other space heating appliances which use hot water to generate the heat output, returning through the heating inlet pipe 10.

A thermostatic valve 15 is provided on the outlet pipe 6 leading from the first heat exchanger 3 to the outlet source pipe 2. Similarly, a thermostatic valve 16 is provided on the outlet source pipe 2 adjacent to the second heat exchanger 7. Those thermostatic valves 15, 16 can be used to regulate the flow of hot water from the source through the two heat exchangers according to demand.

A flow meter 17 is provided in the outlet source pipe 2 downstream of the junction with the pipe 6, for measuring the flow rate of water from the hot water source and the temperature of the water returned to the source. Provided that the temperature of the water entering from the hot water source is reasonably constant those measurements enable the energy consumed by the installation to be calculated.

Also shown in Fig. 1 are ball valves 18 which can be manually actuated to isolate various parts of the system.

As will be understood, appropriate electrical controls (not shown) are also provided for controlling the thermostatic valves 15, 16 and the pump 14.

In operation, with payment made and the ball valves 18 open, hot water flows into the installation along the inlet source pipe 1. Some of that water flows along pipe 4, through the heat exchanger 3 and along pipe 6 to the outlet -11 -source pipe 2 where it flows back out of the installation.

The rest of the water entering along the inlet source pipe flows through the heat exchanger 7 and back along the outlet source pipe 2. The thermostatio valves 15 and 16, downstream of the heat exchangers 3 and 7 respectively, are able to shut off the flows when required to control the heating. As will be understood cold water enters the heat exchanger 3 along the pipe 8 and, after being heated in the heat exchanger, leaves by the pipe 9 from whioh it can be fed to hot water outlet taps. Similarly water in the space heating circuit enters the heat exchanger 7 along the pipe and, after being heated, leaves the heat exchanger along the pipe 11. The pump 14 maintains the flow of the water around the circuit through the heat exchanger 7.

Fig. 2 shows an installation which in most respects is very similar to the installation shown in Fig. 1 and the same components are referenced by the same reference numerals in the two Figures. In the description below only the differences between the arrangement of Fig. 2 from that of Fig. 1 will be described.

In Fig. 2 the valve 13 controlled by the prepayment meter 12 is replaced by two valves 19 and 20, both controlled by the prepayment meter. The valve 19 is in the heated water pipe 9 leading from the first heat exchanger 3, for supplying hot water to the dwelling. The valve 20 is in the section of the outlet source pipe 2 that leads from the second heat exchanger 7 and is upstream of the connection of the outlet pipe 6 to the outlet source -12 -pipe 2. Tn the absence of payment, the prepayment meter is arranged to close both the valves 19 and 20. In that way both the water heating and space heating are disabled, although there is still a flow path from the inlet source pipe 1 tc the outlet source pipe 2 via the pipes 4 and 6.

The valves 19 and 20 can each be made much less substantial and therefore less expensive than the valve 13 in the arrangement of Fig. 1.

Whilst Fig. 2 illustrates one particular example of the invention, it should be understood that many variations are possible. For example, there may be two or more space heating water circuits associated with the heat exchanger 7; that allows different space heating hot water circuits to employ water controlled to different temperatures. !I!he heat exchangers 3 and 7 may take any of a wide variety of forms.

In an alternative embodiment of the invention, the second heat exchanger 7 is omitted and the inlet and outlet source pipes 1 and 2 are connected directly to one or more radiators, towel rails or other heaters. Such a direct heating arrangement avoids the need to provide a second heat exchanger but reduces the flexibility of control over the temperature of the working fluid in the space heating arrangement because the water in the inlet source pipe is used directly.

Where in the foregoing description, integers or

elements are mentioned which have known, obvious or foreseeable eguivalents, then such equivalents are herein -13 -incorporated as If Individually set forth. Reference should be made to the claims for determining the true soope of the present invention, which should be construed so as to encompass any suoh equivalents. It will also be appreciated by the reader that integers or features of the invention that are described as preferable, advantageous, convenient or the like are optional and do not limit the scope of the independent claims.

Claims

-14 -Claims: 1. 7&n installation for supplying hot water and space heating to a user, the installation comprising: an inlet source pipe for connection to a supply pipe of a source of hot water; an outlet source pipe for returning the water that has entered the installation through the inlet source pipe; a first heat exchanger for receiving hot water from the inlet source pipe and returning it to the outlet source pipe after receiving heat; a heat receiving appliance for supplying space heating, connected in parallel to the first heat exchanger for receiving hot water from the inlet source pipe and returning it to the outlet source pipe after receiving heat; a water supply inlet pipe for connection to a water supply to be heated and including a pipe for supplying water to be heated to one or more conduits passing through the first heat exchanger; a heated water pipe for supplying heated water to a user, the heated water pipe being connected to receive water from the one or more conduits passing through the first heat exchanger; a prepayment meter for controlling the supply of hot water and space heating to a user; wherein the prepayment meter is arranged to control a first valve in a flowpath connected in series with the one or -15 -more conduits in the first heat exchanger for preventing the flow through the one or more conduits in the absence of payment, and is alsc arranged to ccntrcl the opening of a second valve operable to control the operation of the space heating.
2. An installation according to claim 1, in which the second valve is connected in series with the flowpath through the heat receiving appliance of the hot water from the inlet source pipe.
3. An installation according to claim 2, in which the second valve is connected downstream of the heat receiving appliance in the fiowpath through the appliance.
4. An installation according to claim 2 or 3, in which the second valve is connected in a portion of the flowpath that is:n parallel with the flowpaths to and from the first heat exchanger.
5. An installation according to any preceding claim, in which the first valve is connected downstream of the first heat exchanger in the flowpath connected in series with the one or more conduits passing through the first heat exchanger.
6. An installation according to any preceding claim, in which water received in the first heat exchanger from the inlet source pipe is arranged to pass through a plurality of conduits in proximity to the one or more conduits for water to be heated, for transferring heat from the water passing through the plurality of conduits to the water passing through the one or more conduits.

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7. An Installation according to any preceding claim, in which the heat receiving appliance is a second heat exchanger and the installation further comprises: a heating inlet pipe for supplying liquid to be heated to one or more conduits passing through the second heat exchanger; and a heating outlet pipe for supplying heated liquid to one or more space heating appliances, the heating outlet pipe being connected to receive liquid from the one or more conduits passing through the second heat exchanger.
8. An installation according to claim 7, in which water received in the second heat exchanger from the inlet source pipe is arranged to pass through a plurality of conduits in proximity to the one or more conduits for liquid to be heated, for transferring heat from the water passing through the plurality of conduits to the liquid passing through the one or more conduits.
9. An installation according to claim 7 or 8, in which the liquid that the heating inlet pipe is arranged to supply is water.
10. An installation according to any of claims 7 to 9, further including a pump for pumping liquid through the heating inlet pipe and the heating outlet pipe.
11. An installation according to any of claims 1 to 6, in which the heat receiving appliance comprises one or more radiators or towel rails.

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12. An installation according to any preceding claim, further including means for measuring the heat taken from the source of hot water.
13. An installation acoording to any preceding claim, further including a thermostatic valve for controlling flow of water from the inlet source pipe to the first heat exchanger.
14. An installation according to any preceding claim, further including a thermostatic valve for controlling flow of water from the inlet source pipe to the heat receiving appliance.
15. An installation for supplying hot water and space heating to a user, the installation being substantially as herein described with reference to Fig. 2 of the accompanying drawings.
16. A district heating or central plant system comprising means for generating a source of hot water and a multiplicity of installations, each according to any preceding claim, connected to the source of hot water.
17. A method of operating an installation according to any of claims 1 to 15.