GB2125158A

GB2125158A - Heat-exchanger device

Info

Publication number: GB2125158A
Application number: GB08320913A
Authority: GB
Inventors: Salah Djelouah
Original assignee: Sorelec
Current assignee: Sorelec
Priority date: 1982-08-03
Filing date: 1983-08-03
Publication date: 1984-02-29
Also published as: IT8321907A0; AU570411B2; GB2125158B; BE896996A; ES8404501A1; PT76882B; IT1163649B; DE3325535A1; AR231190A1; CH654400A5; BR8303153A; ES524469A0; AU1578383A; GB8320913D0; PT76882A

Abstract

A heat-exchanger device for heating and air-conditioning rooms, using solar energy, has the reserve tank 14 and connection of the heat- vehicle liquid to atmosphere situated in the top part of the heat-vehicle liquid circuit above the heat- exchanger (7) of the storage tank (6). Tank (6) has an insulation layer (5) surrounded by a transparent heat- exchange casing containing an outer volume (4) of the heat transfer fluid circuit which includes heat-exchanger (7). Fluid in volume (4) receives or yields heat. <IMAGE>

Description

SPECIFICATION Heat-exchanger device This invention relates to a spherical or cylindrical heat-exchanger device for heating and air-conditioning rooms and for producing hot water and cold water for sanitary purposes, comprising an exchanger and a storage volume, the said device having an inner chamber forming the primary heat-vehicle fluid storage volume, an insulating casing surrounding the storage volume and a heat-exchange surface formed at least largely by the primary heat-vehicle circuit, said exchange surface being disposed outside the insulating casing, and it comprises a transparent outer casing, in which device the heat-vehicle fluid circuit is an open circuit passing through an exchanger inside the storage volume, and comprises a heat-vehicle liquid tank. A device of this kind is known.

The object of this invention is to describe a heat-exchanger device of the type described above to provide a better heat-exchange between the heat-vehicle liquid and the liquid contained in the storage tank, this improvement being achieved by simple means.

To this end, the invention relates to a heatexchanger device characterised in that the heatvehicle liquid tank is situated in the top part of the heat-vehicle liquid circuit above the storage tank heat-exchanger.

By providing the heat-vehicle liquid tank in the top part, both the outer heat-exchanger volume and the heat-exchanger volume disposed inside the storage tank are always filled with heatvehicle liquid. At the storage volume heatexchanger this considerably improves the efficiency of the heat exchange and hence the general efficiency of the heat-exchanger device.

By disposing the heat-vehicle liquid tank in the top part of the device, i.e. above the coil, practically at the place where the liquid which has circulated in the outer heat-exchange casing discharges, gas is prevented from accumulating in the top part of the circuit and the same applies to gas blockages which impeded the flow of heatvehicle liquid and thus appreciably reduce the efficiency of the installation.

Any excess pressure effects in the event of overheating or frost are also obviated since the liquid can flow freely in the tank, which is in turn open freely to the surrounding atmosphere.

The invention will be described in greater detail with reference to the accompanying drawings, wherein: Fig. 1 is a section of a heat-exchanger device according to a first embodiment of the invention.

Fig. 2 is a diagram of a second embodiment.

Fig. 3 is a section of an alternative.

Referring to Fig. 1 , the heat-exchanger device in this case comprises a unit of spherical shape consisting of a base 1 bearing the actual heatexchanger device and accommodating the various control circuits together with the circulation pump, or circulator, valves, etc., and any components to which access is required.

The actual heat-exchanger device comprises an outer spherical casing 2 which together with an inner spherical casing 3 defines a heat-exchange volume through which the heat vehicle liquid flows. Inside casing 3 is an insulating casing 5 surrounding a tank 6, the shape of which is preferably similar to that of the casings 2 and 3, i.e. a spherical tank in this case. The inside of tank 6 contains a heat-exchanger 7 in the form of a coil which forms part of the heat vehicle liquid circulation circuit.

The heat vehicle liquid circuit comprises the outer volume or chamber 4 in which the heatvehicle liquid flows either to receive or yield up heat. The circuit also comprises the heatexchanger 7 which exchanges the heat (or the cold) of the heat-vehicle liquid with the liquid stored in the tank 6. Cold is produced by reversal of the direction of flow in the heat-vehicle liquid.

In the bottom part the outlet of the heat exchanger 7 is connected to a flow pump 8 which is intended to circulate the heat-vehicle liquid in the direction of arrows A, B in the heat-vehicle liquid circuit. At the outlet the pump 8 is connected to a T-piece 9 which is in turn connected to a pipe 10 and to a pipe 1 These two pipes (there may be other than two) are each connected to part of the heat-exchange volume 4.

Although not shown in the drawings, it is advantageous to subdivide the exchanger volume 4 in the vertical or substantially vertical direction into at least two parts, of which one 4 is intended to extend southwards and the other, 12, northwards. Since pipe 11 contains a flow reducer 1 3, it is thus possible to reduce or shut off the flow of heat-vehicie liquid in the direction of arrow B to the part 12 of the heat-exchange volume. In this way it is possible to prevent the heat-vehicle liquid from flowing in that part of the casing 12 which is no longer subject to solar radiation and which then emits a thermal radiation which cools the heatvehicle liquid.

In the top part of the installation the two volumes 4 and 12 lead into a tank 14 through liquid outlets 15. The tank 14, which communicates with the external atmosphere, forms a balancing tank which enables the excess pressures to be absorbed while obviating any accumulation of gas in the top part of the heatvehicle liquid circulation circuit, since such accumulation of gas might result in blockages which would impede the flow of heat-vehicle liquid.

The outlet pipe 1 6 of the heat exchanger 7 also contains a flow reducer 1 7 enabling the flow of heat-vehicle liquid to be stopped or reduced.

Temperature probes 19, 20 are provided to monitor the operation of the installation, and start or stop the circulation pump etc. Tank 14 is closed by an insulating cover 21 provided at the top liquid inlets 1 5.

As a result of the high location in the top part of the tank 14, the heat-vehicle liquid circulation circuit is always filled with heat-vehicle liquid, on the one hand, in the volumes 4 and 12 because of the circulating pump 8 and, on the other hand, in the heat-exchanger 7 since, as iliustrated, during operation the liquid in the tank 14 can reach or exceed the level 22. Since the heat-exchanger 7 is always filled with liquid, this greatly improves the heat exchange at the exchanger 7, which is preferably in the form of a coil occupying the largest available volume in the bottom part of the tank 6, i.e. in that part of tank 6 in which the stored liquid is the coldest. It is advantageous to devise the exchanger 7 by arranging the coil so as to promote the convection movements of the liquid in the tank 6 as effectively as possible.To that end, the coil is advantageously disposed in a hemispherical, conical or cylindrical surface and preferably in the bottom part of the tank 6. To obviate fatigue problems due to expansion phenomena, it is advantageous to connect the pipes 10, 11 to the chamber volumes 4, 12 via loops 1 Oa,11 a.

Fig. 2 relates to another embodiment comprising a first or main circuit for the flow of heat-vehicle fluid and a second or auxiliary circuit in which a refrigerant fluid flows which completes the action of the first circuit and improves its efficiency. The first circuit is similar to that of the first embodiment and comprises an exchange surface 30 forming an absorber connected to a tank 31 in the top part, and a collector 32 in the bottom part. Tank 31 is connected to atmosphere.

The circuit also comprises a circulating pump or circulator 33 which circulates the heat-vehicle fluid of the main circuit. The circuit finally comprises an exchanger 34 disposed in the storage tank 35. The auxiliary circuit comprises an exchanger 36 housed in the top tank 31 which operates as a condenser, and an exchanger 37 housed in the collector 32, which forms an evaporator. This circuit, which is preferably provided with a compressor 38, also includes an exchange surface 39 of larger or smaller size.

The circuit contains a heat-vehicle fluid operating at a lower temperature than the heatvehicle fluid of the main circuit; this heat-vehicle fluid is preferably a refrigerant fluid, i.e. a fluid which carries out compression condensation evaporation cycles. In practice, the size of the exchange surface 39 of the auxiliary circuit varies with the conditions of use of the heat-exchanger device. This exchange surface 39 generally forms part of the casing which also forms the exchange surface of the main circuit.In some cases, the exchange surface 39 is dispensed with and the auxiliary circuit consists solely of the two heat exchangers 36, 37. Exchanger 37 enables the fluid of the auxiliary circuit to recover the residual heat from the fluid of the main circuit in order to restore it to this fluid via the exchanger 36 in the tank 31 in order to have a hotter fluid at the input to the exchanger 34 in the storage tank 35. The heatvehicle fluid of the primary circuit is heated, on the one hand, by the absorbed solar energy and by the refrigerant fluid, which gives up its heat at the condenser. In another application, the refrigerant fluid flows directly in the absorber thus enabling a large exchange surface to be used.The south side will represent the condenser and the north side the evaporator of the heat pump, which is shown in white, with or without a glasshouse effect. This association allows permanent operation independently of the ambient temperature and has the effect of increasing the performance coefficient of the system and increasing the average temperature of the stored liquid.

According to another embodiment not illustrated, the heat-exchanger device comprises a spherical or cylindrical inner casing, the outer surface of which is decorated, said casing in turn being surrounded by a double casing of corresponding shape in which a black heat-vehicle fluid circulates. The black fluid will mask the landscape printed on the inner sphere as the black liquid rises and receives the solar heat. This blackcoloured fluid absorbs the heat and transfers it to the storage reservoir through a cylindrical or spherical exchanger and the fluid flows by gravity in this exchanger to return to the reserve which in this case is situated in the bottom of the exchanger. On stoppage all the black liquid is recovered in the reserve thus showing a picture or landscape; the system then serves as a decorative element.

Referring to Fig. 3, the heat-exchanger device consists of an assembly of spherical shapes resting on a base 100. The actual exchanger comprises an outer spherical casing 102 which together with an inner spherical casing 103 defines a heat-exchanger volume which forms an absorber and through which the heat-vehicle fluid flows. The absorber volume is divided substantially vertically into two parts, one of which, 112, is intended to face north while the other 104 is intended to face south.

The heat-vehicle fluid delivered by the pump flows through these two parts in series and in that sequence; in this way the fluid is preheated in the part of the absorber 104 facing north, followed by the actual heating of the fluid in the south-facing part.

The temperature of the heat-vehicle fluid passing through the exchanger disposed in the tank is thus at a high temperature, and this improves the efficiency of the installation and enables there to be obtained in the tank a water for sanitary or any other purposes at high temperature.

Inside the absorber 102, 103 is a thermalinsulation casing 105 which surrounds the tank 106 containing the heat exchanger 107. Tank 106 contains the liquid for heating or cooling, which is generally water for sanitary purposes. The heatvehicle fluid circuit also includes a circulation pump 108, an expansion tank 130 and a filler valve 131.

The output of pump 108 is connected by a pipe 132 extending inside the insulating casing 105 to reach the top part 133 of the part 112 of the absorber, i.e. the north-facing part.

The heat-vehicle liquid then flows down in this part of the absorber 112. At the bottom part 134 of the absorber 11 2 the heat-vehicle liquid flows in the bottom part 135 of the south-facing absorber section 1 04. The heat-vehicle liquid rises through this part 104 which, at its top end 136, leads into the coil 107. The heat-vehicle fluid flows down through the coil 107 to exchange heat or cold with the liquid contained in the tank 106.

At the outlet of coil 107 a pipe 1 37 carries the liquid to the inlet to pump 108. Pipe 137 comprises a branch 1 38 provided with a filler valve 131.This pipe also contains the expansion tank 130.

Bleeds 139 for bleeding off the accumulating gases, are provided at the top part of the circuit, i.e. at the top parts 133 and 136.

Claims

1. A heat-exchanger device for heating and airconditioning rooms and for producing hot water and cold water for sanitary purposes, comprising an exchanger and a storage volume, the said device having an inner chamber forming the primary heat-vehicle fluid storage volume, an insulating casing surrounding the storage volume and a heat-exchange surface formed at least largely by the primary heat-vehicle circuit, said exchange surface being disposed outside the insulating casing, and it comprises a transparent outer casing, in which device the heat-vehicle fluid circuit is an open circuit passing through an exchanger inside the storage volume, and comprises a heat-vehicle liquid tank (14), the device being characterised in that the reserve and connection of the heat-vehicle liquid to atmosphere are situated in the top part of the heat-vehicle liquid circuit above the heat exchanger (7) of the storage tank (6).

2. A device according to claim 1, characterised in that the heat-exchange surface is in a single casing or is subdivided into two parts (4, 12) forming parallel branches for the heat-vehicle fluid between the outlet of the heat-exchanger disposed in the storage tank and the heat-vehicle fluid tank (14) disposed in the top part of the circuit.

3. A device according to claim 1, characterised in that the heat-vehicle fluid circuit is provided with a circulating pump (8) and, at the pump outlet, the circuit divides into at least two arms corresponding to different exchange volumes (4, 12) with the exterior corresponding to different solar orientation and capabie of being disconnected (at 1 3) from the heat-vehicle fluid circuit.

4. A device according to claim 1, characterised in that the tank or a device providing the same function (14) for the heat-vehicle liquid is incorporated in the thickness of the insulating casing (5) and the tank is provided with an insulating cover (21).

5. A device according to claim 1, characterised in that the heat-exchanger (7) in the form of a coil corresponds to a hemispherical, cylindrical or conical surface disposed in the bottom part of the storage tank (6).

6. A device according to claim 1, characterised in that it comprises an auxiliary circuit having two exchangers (36, 37), one of which (37) at the outlet of the exchanger (34) forms an evaporator of the main circuit in the storage tank while the other (36) is in the top tank (31) and acts as a condenser.

7. A device according to claim 6, characterised in that the inner casing is decorated and the outer double casing has flowing through it the heatvehicle fluid, which is coloured black and which, when it no longer circulates, returns to its reservoir and allows the decoration to be seen.

8. A device according to claim 1, characterised in that the volume of the absorber (2, 3) is divided substantially vertically into two parts (4, 12), one of which is intended to face south while the other is intended to face north, and these two parts are so connected as to carry the flow in series and in the sequence: north-facing part (12) and southfacing part (4).

9. A device according to claim 8, characterised in that it comprises at the outlet two circulating pumps (8), a pipe (32) delivering the heat-vehicle fluid to the top end of the north-facing absorber part (12), this absorber part communicating at the bottom end with the bottom end of the southfacing absorber part (4).

10. A device according to claim 9, characterised in that the heat-vehicle fluid circuit is a closed circuit provided with an expansion tank (130) and a filler valve (131).

11. A heat-exchanger device substantially as herein described and shown in the accompanying drawings.