GB2187272A

GB2187272A - Heat exchange apparatus

Info

Publication number: GB2187272A
Application number: GB8600392A
Authority: GB
Inventors: John Harry Clarke; Anthony Roland Morton
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-01-08
Filing date: 1986-01-08
Publication date: 1987-09-03
Also published as: GB2187272B; GB8600392D0

Abstract

A heat exchange apparatus comprises a cylinder (10) having an inlet (21) and outlet (20) for water and a heat exchange coil (25) through which hot water may pass from a boiler for example, and a second heat exchange coil (13) which is partially encased by a barrier member (16) and which may comprise a condenser of a refrigeration apparatus. Other heating means may be provided such as an electrically energised immersion heater. <IMAGE>

Description

SPECIFICATION Heat exchange apparatus and systems Description of Invention The present invention relates to heat exchange apparatus and systems and is primarily but not exclusively concerned with the efficient utilisation of heat generated in a refigerant during use of refrigerating apparatus or other cooling apparatus using a refrigerant.

The cycle of operation of a refrigerating or cooling plant using a refrigerant comprises the compression of the refrigerant which raises the temperature of the ref rigerant, followed by expansion when the refrigerant changes state from a liquid to a gas, the change of state from a liquid to a gas drawing in a considerable amount of heat from the surrounds.

Since the purpose of a cooling plant or refrigerator is to draw in heat, then the cycle of operation of compression of the refrigerant generates unwanted heat, which heat is normally dissipated through a radiator.

It has been proposed to utilise the dissipated heat and it has further been proposed to use the dissipated heat to raise the temperature of water for use in the building having the refrigerating or cooling plant.

Unfortunately, problems occur with such arrangements since the thermal output of a small cooling or refrigeration systems is less than the heat generated by a normal hot water heating system, and, if a heat exchanger is provided in a hot water tank so that the compressed refrigerant is pumped through such heat exchanger, if the tank is of a conventional size, for example about 300 litres, then the heat exchanger is only capable of heating such a large volume of water to a small temperature which, if given time, would be quite satis factory. However, it has to be remembered that the water in the tank will be continually replaced as the water is used, thus the water is unlikely to reach a satisfactory temperature.

Further problems arise in that in normal use of the refrigerating plant, depending on the amount of hot water required, it is unlikely that in most premises the refrigerating plant will be able to produce sufficient heat output to heat the amount of water required to a predetermined desired temperature.

It is an object of the present invention to provide a new or improved heat exchange apparatus.

According to a first aspect of the invention, we provided heat exchange apparatus comprising a container for liquid, said container having an upper end from which liquid may be drawn and a lower end into which liquid may flow, a first heat transfer fluid flow path sealed relative to said container to prevent mixture of said liquid and said fluid, and a second heat transfer fluid flow path, wherein said first heat transfer fluid flow path is at least partially surrounded by barrier means to form an enclosure communicating with both upper and lower areas of said container.

The apparatus of the present invention en ables heating of the liquid, which it is envisaged will normally be water, by conventional heat exhange means energised by gas, oil or electricity for example, and also by the compressed refrigerant which flows through said first heat transfer fluid flow path.

The enclosure formed by the barrier means has the effect of decreasing the amount of water heated by the compressed refrigerant and thus enables the smaller quantity of water heater to reach a higher temperature than would be the case if a large amount of water was heated. The design of the enclosure ensures that water heated by the refrigerant migrates to the upper end of the container without being unduly cooled by the remaining liquid or water which will be at a lower temperature.

Preferably, the first heat transfer fluid flow path is situated in the lower part of the container in said enclosure and connecting a pipe extending from said enclosure to the upper area of said container.

A further advantage is gained by siting the first heat transfer fluid flow path adjacent the lower end of the container since, even though the heat exchanger heats a relatively small quantity of water, the process is continuous and one batch of water having been so heated will be replaced by cold water which is then heated by the refrigerant in the first heat transfer fluid flow path, thus it is ensured that there is always at least a small quantity of hot water.

The second heat transfer fluid flow path, which is preferably also sealed relative to said container to prevent mixture of the liquid in the container and the fluid used in said second heat transfer flow path, may be brought into operation as desired and possibly in conjunction with thermostatic controls and information concerning likely demand to ensure that there is an adequate supply of heated liquid.

Preferably, said container is also provided with provision for further heating means which may comprise electrically energised heating elements which also may be controlled thermostatically and in accordance with an expected demand of heated liquid.

It is further object of the present invention to provide, in combination, a refrigerating or cooling apparatus in conjunction with heat exchange apparatus as aforedescribed.

According to a second aspect of the invention, we provide a cooling or refrigeration apparatus comprising a refrigerant flow path including an evaporator and a compressor, wherein said heat exchange apparatus comprises a container as aforedescribed and wherein said first heat transfer fluid flow path is connected to said refrigerant flow path, after said refrigerant has passed through said compressor and prior to the evaporater.

Preferably, said refrigeration apparatus includes further heat dissipating means, operation of which or fluid transfer to which is only effected if the temperature of the liquid surrounding said first heat transfer fluid flow path reaches a predetermined value.

The provision of additional heat dissipating means may be necessary during continuous operation of the cooling or refrigeration plant and in combination with a small demand for water. If the temperature of the liquid surrounding the first heat transfer fluid flow path reaches a predetermined hot value, then insufficient heat will be able to be dissipated by the refrigerant leading to faulty operation of the refrigerating or cooling system.

The provision of additional heat dissipating means, which may only be brought into operation if insufficient heat can be dissipated into the liquid from the refrigerant overcomes such a problem.

It will be appreciated that in addition to refrigerating systems, cooling or air conditioning systems which maintain the temperature at a value lower than that of the surrounding air, are highly suitable for connection to the heat exchange apparatus as aforedescribed.

According to a still further aspect of the invention, we provide an air cooling apparatus in combination with heat exchange apparatus as aforedescribed wherein said air cooling apparatus incorporates a coolant flow path, said coolant being expanded to permit of cooling to the surrounding air and subsequently compressed, and wherein said compressed coolant is passed through said first heat exchange fluid flow path.

The apparatus will now be described by way of example only, with reference to the accompanying drawings, wherein: FIGURE 1 is an ill ustration of an heat exchange apparatus of the present invention; and FIGURE 2 is a schematic view of an air cooling apparatus connected to the heat exchange apparatus.

Referring first to Figure 1, one example of a heat exchange apparatus of the present invention is shown and comprises a container, in the form of a copper cylinder 10, the cylinder being supported by legs 11 and being surrounded by a layer of insulating material 12.

A first heat transfer fluid flow path is provided in the form of a coil 13 having an inlet 14 and an outlet 15, the coil 13 being bounded by a barrier 16 so as to form an enclosure around the coil 13.

The enclosure is in flow communication with liquid in the tank 10 at the bottom end thereof and at the upper end is connected to a pipe 17 which communicates with the upper area 18.

In use of the apparatus, when the tank 10 is full of cold water and hot refrigerant is passed through the coil 13, the water within the enclosure formed by the barrier 16 will be heated and on being heated migrates up the tube 17 to the area 18 of the tank 10. As the hot water migrates upwards through the pipe 17, the water will be replaced by cold water from the lower end of the tank.

The tank 10 is provided with an outlet 20 from which hot water is drawn off, a cold water feed inlet 21 through which cold water is fed into the tank, and a secondary return 22 for hot or warm water returned if the hot water supply is on a "loop system".

A second heat transfer fluid flow path is provided and comprises a coil 25 having an inlet 26 and an outlet 27. The coil 25 may be connected to a normal water heating boiler powered by any sort of suitable fuel which heats water within the boiler and which passes through the coil 25.

It is envisaged that in normal circumstances, the heat transfer capability of the coil 25 will be far greater than the heat input from the refrigerant passing round coil 13.

The tank 10 may also be provided with immersion heaters (not shown) which may be connected to apertures 28 and 29, the electrically heated elements extending into the water or other fluid in the tank 10.

It will be appreciated that a variety of controls may be used with the heat exchange of the present invention and in particular may be used to ensure that the water in the tank 10 surrounding the coil 13 is of a sufficiently low temperature to ensure that sufficient heat is dissipated from the refrigerant in order that the refrigerator or cooling pump may operate correctly. Furthermore, controls may be provided to sense the heat input from the refrigerant through coil 13 and possibly with information concerning the expected demand of hot water, such controls may influence the operation of heating means which passes heating fluid through coil 25 for operation of immersion heaters 28 and 29.

A schematic control system is shown in more detail with reference to Figure 2.

Referring now to Figure 2, a schematic control system is shown comprising a tank 10 having a hot water outlet 20, a refrigerating or cooling system 40 in which the refrigerant path is connected to inlet 26 and outlet 27 of a coil 13, and via valves 41 and 42 to a radiator 43 which may be cooled by a motorised fan 44.

A conventional hot water heating system, i.e. a gas fired boiler for example, 45 has a fluid transfer flow path 46 connected to a second coil 25 provided in the tank 10.

A control system 50 which may incorporate electronic circuitry including a microprocessor is provided with a plurality of input informa tion. If, for example, the cooling plant 40 is intended to cool a certain area, for example a room where beer is stored, then a predetermined input temperature would be programmed into the microprocessor and temperature sensing devices will indicate the actual temperature in the cellar. The cooling system 40 will then be brought into operation when required, by a thermostat for example, to maintain the cellar temperature at the desired temperature.

Assuming that the desired temperature is such that the cooling apparatus 40 has to operate for fairly long periods, then the refrigerant will be warmed when compressed, which heat may be transferred via coil 13 to heat hot water in the tank 10.

The temperature of the refrigerant, both leaving the cooling apparatus 40 and returning thereto, may be monitored to ensure that sufficient heat transfer from the refrigerant has taken place in the tank 1 0 so that the cooling apparatus may operate correctly. If however, the monitored temperatures do not show a significant difference, i.e. no significant cooling is taking place in the tank 10, then in order that the cooling system can operate satisfactorily to maintain the cellar temperature, valves 41 and 42 may be opened and transfer refrigerant, or at least part of the refrigerant, to a radiator 43 which may if desired be cooled in addition by a motorised fan 44.

Different amounts of hot water may be required during the day which, depending upon the establishment to which the apparatus is fitted, may be predictable and, the tank 10 may be provided with water temperature sensors (one of which is shown at 55) which by their positioning may indicate both the temperature and the approximate amount of water at a certain temperature within the tank.

If the operation of the cooling system 40 is sufficient to provide limited amounts of hot water sufficient to meet the need, then operation of the water heater 45 is not necessary.

However, when the cooling apparatus 40 is not being used because, for example, the cellar temperature is at the desired temperature, or large quantities of hot water are required, then the water heater 45 may be brought into operation by the control means 50.

As a further alternative, if the refrigerant is providing almost all the heat required, then the control system 50 may initiate operation of an electrical heater 52 for a required period of time, if the information it has programmed therein or receives indicates that even though the basic source of energy may be more expensive, the short time required for the heater to operate may make the electrical heater more efficient from a cost point of view.

The embodiment above described is a simplified version of a variety of different control systems which may be used with the apparatus of the present invention.

It will be appreciated that the more information that can be programmed into the control system, and the more information concerning what is happening throughout the system, i.e.

water temperatures, volume, demand etc., that can be provided to the control means, the more efficiently it will be able to operate the system.

The features disclosed in the foregoing description, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, or a class or group of substances or compositions, as appropriate, may, separately or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

1. Heat exchange apparatus comprising a container for liquid, said container having an upper end from which liquid may be drawn and a lower end into which liquid may flow, a first heat transfer fluid flow path sealed relative to said container to prevent mixture of said liquid and said fluid, and a second heat transfer fluid flow path, wherein said first heat transfer fluid flow path is at least partially surrounded by barrier means to form an enclosure communicating with both upper and lower areas of said container.

2. Heat exchange apparatus according to Claim 1 wherein said fi rst heat transfer fluid flow path is situated in the lower part of the container and said enclosure is connected by a pipe extending from said enclosure to the upper area of said container.

3. Heat exchange apparatus according to Claim 1 or Claim 2 wherein said second heat transfer fluid flow path is sealed relative to said container.

4. Heat exchange apparatus according to any one of the-preceding claims wherein said container is provided with provision for further heating means.

5. Heat exchange apparatus according to Claim 4 wherein said further heating means comprises electrically energised heating elements.

6. Heat exchange apparatus according to any one of the preceding claims wherein said first heat transfer fluid flow path comprises a coil of material having good thermal conductivity.

7. A cooling or refrigeration apparatus comprising a refrigerant flow path including an evaporator and a compressor, wherein said heat exchange apparatus comprises a container as claimed in any one of the preceding claims and wherein said first heat transfer fluid flow path is connected to said refrigerant flow path, after said refrigerant has passed through said compressor and prior to the evaporater.

8. Apparatus according to Claim 7 wherein said refrigeration and cooling apparatus includes further heat dissipating means, operation of which or fluid transfer to which is only effected if the temperature of the liquid surrounding said first heat transfer fluid flow path reaches a predetermined value.

9. Apparatus according to Clim 7 or Claim 8 wherein said cooling or.refrigeration apparatus comprises air cooling apparatus.

10. Heat exchange apparatus substantialy as hereinbefore described with reference to and as illustrated in Figure 1 of the accompanying drawings.

11. A cooling and heat exchange system substant iaIl y as hereinbefore described with reference to and as illustrated in Figure 2 of the accompanying drawings.

12. Heat exchange apparatus including any novel feature or novel combination of features disclosed herein and/or illustrated in the accompanying drawings.