GB2498850A

GB2498850A - Heat exchanger

Info

Publication number: GB2498850A
Application number: GB1222694.0A
Authority: GB
Inventors: Martin Muller
Original assignee: Weiss Klimatechnik GmbH
Current assignee: Weiss Klimatechnik GmbH
Priority date: 2011-12-30
Filing date: 2012-12-17
Publication date: 2013-07-31
Also published as: DE202011052548U1; NL2010008C2; GB201222694D0; NL2010008A

Abstract

A heat exchanger 14 comprises a first heat exchanger 32 in a first fluid circuit (12, fig 1), a second heat exchanger 46 in a second fluid circuit (16). The first and second heat exchangers define a heat exchanger package 54 embedded in an accumulator medium 52 in a container (176, fig 4c) and are arranged in cross-counterflow. The first heat exchanger may be an evaporator in a refrigeration circuit and the second heat exchanger may be a water cooler in a water circuit. The accumulator medium may be a heat storage paraffin mixture from crude oil. The heat exchangers may be a plurality of copper pipes 64, 68, 72, 76, 80, 84, 88, 92 with copper fins 84 spaced along the length of the package. An air conditioning system containing the heat exchanger is also claimed and provides cooling of a diver pressure chamber and maintains its temperature during power failure.

Description

HEAT EXCHANGER WITH ACCUMULATOR MEDIUM AND AIR

CONDITIONING SYSTEM

The invention relates to a heat exchanger with an accumulator medium containing paraffin, comprising a charging heat exchanger connectable with a charging circuit such as a refrigeration circuit and a discharging heat exchanger connectable with a discharging circuit such as water circuit and to an air conditioning system, comprising a primary charging circuit, designed as a refrigerant circuit, which is coupled with a secondary discharging circuit via a heat exchanger having an accumulator medium.

A heat exchanger with an accumulator medium is described in DE-27 41 829 Al. The heat exchanger is designed as a latent heat accumulator with an accumulator medium consisting of paraffin and comprises an accumulator with container walls, an accumulator medium, a ventilation pipe and two pipe coils running through the accumulator medium. One of the pipe coils, for example, is connected with a solar collector, while the other pipe coil is to supply process water for a heating or showering system.

There are plastic-sheathed particles in the heat exchanger container. These consist of paraffin and a plastic film or a varnish layer. The paraffin particles sheathed with a plastic film form the heat accumulator medium, wherein the space between the sheathed paraffin particles is filled with a fluid, e.g. water.

EP-2 177 255 Al reveals a refrigeration dryer, in particular a compressed air refrigeration dryer for drying a gaseous fluid and cooling down the gaseous fluid using a refrigeration fluid. The refrigeration dryer comprises a pressurised fluid refrigerant heat exchanger in which, indirectly or directly, the gaseous fluid is cooled down by a refrigeration fluid conveyed in a primary circuit and one or several refrigerant compressors to operate the primary circuit and a cold accumulator, with a heat exchanger on the accumulator side, said heat exchanger coupling an accumulator discharge fluid to a cold accumulator medium, wherein pressurised fluid refrigerant heat exchangers and cold accumulators are fluidly connected via a discharge circuit for an accumulator discharge fluid or can be brought into a fluid connection.

Based on this, the underlying task of the present invention is to further develop a heat exchanger and an air conditioning system such that their levels of efficiency are improved.

According to the invention, the task, inter alia, is solved by the heat exchanger and the discharging heat exchanger being arranged as a heat exchanger package according to the cross-counterf low method, wherein the heat exchanger package is arranged in a container and effused with the accumulator medium designed as a sealing compound such that the heat exchanger package is embedded in the accumulator medium. This achieves a high level of efficiency.

The charging heat accumulator is preferably designed as an evaporator of the refrigeration circuit for cooling the accumulator medium, and the discharging heat exchanger is designed as a water cooler of the water circuit on the secondary side.

Preferably, the charging heat exchanger and the discharging heat exchanger each have pipeline systems nested with each other according to the cross-counterflow method.

A preferred embodiment is characterised in that the charging heat exchanger and the discharging heat exchanger each have pipelines extending along a longitudinal extension of the container, said pipelines each being diverted via bends on the front side and the ends of which are connected with an inflow and an outflow each.

To achieve an improved coupling of the heat exchangers, the pipelines of the heat exchanger package are each arranged in several, preferably four planes, wherein, within a plane, pipelines of the charging heat exchanger are arranged with pipelines of the discharging heat exchanger next to each other and/or on top of each other.

Furthermore, it is intended that fins are arranged transverse to the pipelines.

The fins form a fin package, wherein a distance A between two adjacent fins is in the range mm «= A «= 10 mm, preferably A = 8 mm, and wherein the fins preferably extend over the entire length of the heat exchanger package.

According to a further preferred embodiment, it is intended that the discharging circuit be a water circuit, comprising an air cooler arranged in a diver compression chamber, a pump, a three-way valve and a discharging heat exchanger designed as a water cooler, wherein, preferably, an output of the water cooler is connected with an input of the three-way valve and a cold water connection of the air cooler, wherein a hot water output of the air cooler is connected with an input of the pump and an output of the pump is connected with an input of the valve, and wherein an output of the valve is connected with an input of the water cooler.

To ensure the energy supply of the secondary circuit in case the primary circuit fails, it is intended that the water circuit be supplied with electric energy by an emergency power generator.

In the heat exchanger, preferably, a thermostat is arranged, preferably a mechanical pressurised gas sensor, by means of which the refrigeration circuit can be switched off at a specified temperature.

A pai-ticulai-ly good heat transfer is achieved if the chaiging heat exchanger, the discharging heat exchanger and/or the fins are made of copper or aluminium or contain copper or aluminium.

Furthermore, the invention relates to an air conditioning system, comprising a primary charging circuit designed as a refrigerant circuit, said primary charging circuit being coupled, by means of a heat exchanger having an accumulator medium, with a secondary discharging circuit.

It is characterised in that the heat exchanger is designed as a buffer accumulator and detachably connected with the charging circuit, that the discharging circuit has a water cooler embedded in the accumulator medium of the heat exchanger, an air cooler for cooling a power pack and a pump and a valve, wherein the air cooler, the pump and the valve are connected with an emergency power supply unit, so that the water circuit can function independently after uncoupling the heat exchanger from the cooling circuit.

Preferably, the valve is designed as a three-way valve, wherein an input of the valve is connected with an output of the pump, an output of the pump is connected with an input of the water cooler and an output of the valve is connected with an output of the water cooler and a cold water connection of the air cooler.

Further details, advantages and features of the invention follow not only from the claims, the features to be gleaned from these -for themselves and/or in combination -but also from the following description of preferred execution examples to be gleaned from the drawing.

Therein: Fig. 1 shows a schematic representation of an air conditioning system with a heat exchanger having an accumulator medium; Fig. 2 shows a perspective representation of a first embodiment of a heat exchanger package of the heat exchanger; Fig. 3 shows a schematic side view of the heat exchanger package; Figs. 4a), b), c) show a side, front and rear view of a second embodiment of a heat exchanger package of the heat exchanger; and Figs. 5a), b) show schematic side views of the heat exchanger package.

Fig. 1 shows, purely schematically, an air conditioning system 10, comprising a primary charging circuit designed as a refrigerant circuit 12, said primary charging circuit being coupled, via a heat exchanger 14, with a secondary discharging circuit 16 designed as a water circuit.

The refrigerant circuit 12 comprises a compressor 18 which pumps a refrigerant into a condenser 20. The condenser 20 is connected with a collector 22 which is connected with a dryer 26 via a valve 24. The dryer 26 is connected, via a sight glass 28, with a thermostatic injection valve 30 by means of which the refrigerant is injected into a charging heat exchanger embedded in the heat exchanger 14 and designed as an evaporator 32.

In the execution example shown, the discharging circuit 16 is designed as a cold water circuit and comprises a cooler 34 which, for example, is arranged in a diver pressure chamber, in order to cool its internal space, in particular to set it to a constant temperature of approximately 29°C. The cooler 34 comprises fins 36 which are thermally coupled with a cold water line 38 and which are exposed to an air flow, generated by a ventilator 40, for cooling the internal space.

A hot water connection of the cooler 34 is connected with a pump 42 which is connected with an input A of a three-way valve 44. An output AB of the three-way valve 44 is connected with the input of a discharging heat exchanger designed as water cooler 46, said discharging heat exchanger being embedded in the heat exchanger 14. An output of the water cooler 46 is connected with an input B of the three-way valve 44 and with the cold water connection of the cooler 40. The three-way valve 44 is controlled via a thermostat 48 connected with a temperature sensor 50 which captures the temperature of the water between the cooler 40 and the input of the pump 42.

The heat exchanger 14 is designed as a buffer accumulator and comprises an accumulator medium 52 made from a paraffin mixture. In the accumulator medium 52, which is designed as a sealing compound, both the evaporator 42 of the refrigerant circuit 12 and the water cooler 46 of the discharging circuit 16 are embedded, e.g. cast.

The accumulator medium 52 is cooled to a medium temperature of approximately 2°C to 4°C by means of the embedded evaporator 32 of the refrigerant circuit 12 using a semi-hermetic compressor and its refrigeration components. The water cooler 46, which is also embedded in the accumulator medium 52, is available for cooling down the discharging circuit 16. In the accumulator space, a thermostat is arranged via which the refrigerant circuit 12 is switched off if a predetermined temperature is reached.

During normal operation, the three-way valve 44 operates as a bypass, whereby water is conveyed over the distance A-B. As soon as the water falls below a specified temperature, the valve 44 is selected such that the water is conveyed over the distance A-AB into the water cooler 46 and cooled by the accumulator medium 52.

Fig. 2 shows, purely schematically, a first embodiment of a heat exchanger package 54 of the heat exchanger 14, embedded in the accumulator medium 52. In this heat exchanger package, the evaporator 32 and the water cooler 46 are arranged according to the cross-counterilow method. The evaporator 32 comprises two pipe systems 56, 58 which are connected with an infeed 62 via a valve 60.

The pipe system 58 comprises pipelines 64, 68 running along the longitudinal extension of the heat exchanger 14, said pipelines being connected at the ends via diverting bends 66, 70, 74.

Starting from the bend 66, a return line 68 runs to a bend 70 which is connected with a line 72 with a diverting bend 74 which finally, via a return line 76, is connected with the output 78 for the coolant.

The pipe system 56 of the compressor 32 comprises a pipeline 80 which is connected with a diverting bend 82 at the front, said bend being connected, via a return line 84, with a diverting bend 86 which, in turn, is connected via a pipeline 88 with diverting bend 90 and a pipeline 92 to the output 78.

The water cooler 46 corresponds to the structure of the compressor 32. The pipe systems of the water cooler 46 are nested, according to a cross and counterflow method, with the pipe systems of the compressor 32, as shown in fig. 3 in a schematic cross-sectional representation.

The individual pipe systems 56, 58 are arranged in different planes on top of each another.

Within a pipe system 56, 58, the pipelines 64, 68 or 77, 78 form further planes which are offset from each other. This implements the cross-counterflow method.

Transverse to the pipe systems preferably made from copper, fins 94 are arranged which preferably consist of copper and are thermally connected, such as pressed or welded, with the pipelines. The fins 94 extend over the longitudinal extension of the heat exchanger package and form a fin block.

Fig. 4a shows a side view of a second embodiment of a heat exchanger package 96 of the heat exchanger 14. In this embodiment, too, a water cooler 98 together with an evaporator is embedded in the accumulator medium 52 of the heat exchanger 14, wherein the evaporator 100 together with the water cooler 98 is arranged in a heat exchanger package according to the cross-counterflow method. The water cooler 98 comprises a water inflow 102 and a water outflow 104. The water inflow is connected with a manifold 106 from which three pipelines 108, 110, 112 extend, said pipelines generating a plane which runs parallel or substantially parallel to a bottom surface of a housing of the heat exchanger 14. The pipelines are diverted by pipe bends 116, 118, 120 to a face 114 of the heat exchanger, said face being opposite the manifold 106, then, ataface 122, again diverted via pipe bends 124, 126, 128 and then directed via pipe bends 130, 132, 134 back to a manifold 136 connected with the water outlet 104.

Figs. 4b) and c) show a sectional representation of the face 114 of the heat exchanger package 96. The coolant evaporator 100 comprises a coolant input 138 and a coolant output 140, which is connected with a manifold 142 arranged on the bottom. From the coolant input 138, a distribution takes place to coolant pipes 144, 146, 148 which extend from the face 114 to the opposite face 122, said coolant pipes being diverted here via diverting bends 150, 152, 154, diverted again on the face 114 via bends 156, 158, 160 and diverted on the face 122 via bends 162, 164, 166 so that, finally, the pipe ends 168, 170, 172 end in the manifold 142.

In this embodiment, too, both the evaporator 100 and the water cooler 98 are made from copper, wherein, transverse to the pipelines, fins 174 are arranged which have a distance A in the range of 5 «= A «= 10 mm, preferably A = 8mm.

The invention is characterised in that the evaporator 32, 100 together with the water cooler 46, 98 is fully embedded, e.g. cast, in the accumulator medium 52.

The accumulator medium consists of a paraffin mixture, comprising a mixture of saturated n-paraffinic hydrocarbons from crude oil. The mixture has a melting range of 4°C to 7°C, typically 6°C, and a solidification range of 6°C to2°C, typically 6°C. The density (solid) at - 15°C is 0.88 kg/I and the density (liquid) at +15°Cis 0.77 kg/I. The paraffin mixture has a thermal conductivity of approximately 0.2 W/mk.

The paraffin-based accumulator medium 52 is a special mixture with the property of providing a lot of energy for cooling. Depending on the mixture, with the melting point being adjustable, the energy can be made available over different temperatures.

The heat exchanger 14 comprises a container 176 with bottom 178 and side walls 180, 182, 184, 186. The bottom 178 and the side walls 180 to 186 are preferably insulated, with insulating panels 188, on the inside. The heat exchanger package 54, 96 is arranged in the container 176.

To manufacture the heat exchanger 14, the paraffin mixture which is liquid from approximately 10°C to 12°C is cast into the contaiir 176 preferably made from stainless steel, wherein both the evaporator 32, 100 and the water cooler 46, 100 -except for the inlets outlets 102, 104 or 138, 140-are completely poured in.

During operation, the accumulator medium 52 -as already mentioned -is then cooled by the refrigerant circuit 12 to a temperature in the range of 2°C to 4°C and solidified. In sustainment mode, i.e. if, for example, the power supply for the refrigeration circuit 12 has failed, the energy released by melting enthalpy is used for cooling the water circuit 16. This process begins at a temperature of the accumulator medium of about 10°C.

In the execution example according to fig. 1, the refrigerant circuit 12 has a capacity which is at least twice as large as the capacity needed for cooling the heat exchanger 14; for the refrigerant circuit 12 cools both the accumulator medium 52 and the water circuit 16, i.e. the water for cooling the diver pressure chamber.

The air conditioning system shown in fig. 1 is characterised in that, for example during failure of the energy supply for the refrigerant circuit 12, the cooling energy for cooling the water of the secondary circuit 16 is derived from the heat exchanger 14 then operating as a buffer accumulator. If a diver is in the diver pressure chamber during the failure of the energy supply, the inner temperature can still be set to a constant value of 29°C, irrespective of the external temperature. In this case, the pump 42 and the ventilator 40 are supplied by an emergency power generator. Then there is the possibility of transferring the diver pressure chamber together with the cold-water circuit 16 and the buffer accumulator 14, for example from a ship to a land-based transporter with which the diver pressure chamber together with the diver can be transported to a specialist clinic without the air conditioning of the internal space of the diver pressure chamber failing.

Claims

<claim-text>Claims 1. Heat exchanger (14) with a paraffin-containing accumulator medium (52), comprising a charging heat exchanger (32, 100) connectable with a charging circuit (12) as such as refrigeration circuit and a discharging heat exchanger (46, 98) connectable with a discharging circuit (16) such as a water circuit, characterised in that the charging heat exchanger (21, 100) and the discharging heat exchanger (46, 98) are arranged as a heat exchanger package (54, 96) according to the cross-counterflow method, that the heat exchanger package (54, 96) is arranged in a container (176) and effused with the accumulator medium (52) designed as a sealing compound such that the heat exchanger package (54, 96) is embedded in the accumulator medium (52).</claim-text> <claim-text>2. Heat exchanger according to claim 1, characterised in that the accumulator medium (52) is a paraffin mixture, preferably comprising saturated n-paraffinic hydrocarbons from crude oil.</claim-text> <claim-text>3. Heat exchanger according to claim 1 or 2, characterised in that the accumulator medium (52) has a melting range between 4 to 7°C, preferably 6°C and a solidification range between 6 to 2°C, preferably 6°C.</claim-text> <claim-text>4. Heat exchanger according to any of the preceding claims, characterised in that the charging heat accumulator (32, 100) is designed as an evaporator of the refrigeration circuit (12) for cooling the accumulator medium (52).</claim-text> <claim-text>5. Heat exchanger according to any of the preceding claims, characterised in that the discharging heat exchanger (46, 98) is designed as a water cooler of the water circuit (16) on the secondary side.</claim-text> <claim-text>6. Heat exchanger according to any of the preceding claims, characterised in that the charging heat exchanger (32, 100) and the discharging heat exchanger (46, 98) each have pipeline systems (58, 56; 108, 110, 112; 144, 146, 148) which are nested with each other according to the cross-counterilow method.</claim-text> <claim-text>7. Heat exchanger according to any of the preceding claims, characterised in that the charging heat exchanger (32, 100) and the discharging heat exchanger (46, 98) each have pipelines (64, 68, 72, 78) extending along a longitudinal extension of the container (176), said pipelines each being diverted by bends (70, 86) at the front and their ends being connected with an inflow (60, 138) and an outflow (78, 140) each.</claim-text> <claim-text>8. Heat exchanger according to any of the preceding claims, characterised in that the pipelines of the heat exchanger package (54, 96) each are arranged in several, preferably four planes, wherein, within a plane, pipelines of the charging heat exchanger are arranged next to pipelines of the discharging heat exchanger.</claim-text> <claim-text>9. Heat exchanger according to any of the preceding claims, characterised in that fins (94, 174) are arranged transverse to the pipelines.</claim-text> <claim-text>10. Heat exchanger according to any of the preceding claims, characterised in that the fins (94, 174) form a fin package, wherein a distance A between two adjacent fins is in the rangeS mm «= A «= 10 mm, preferably A = 8mm, and wherein the fins preferably extend over the entire length of the heat exchanger package (54, 96).</claim-text> <claim-text>11. Heat exchanger according to any of the preceding claims, characterised in that the discharging circuit (16) is a water circuit, comprising an air cooler (40) arranged in a diver pressure chamber, a pump (42), a three-way valve (44) and a discharging heat exchanger (46) designed as a water cooler.</claim-text> <claim-text>12. Heat exchanger according to any of the preceding claims, characterised in that an output of the water cooler (46) is connected with an input (B) of the three-way valve (44) and a cold water connection of the air cooler (40), wherein a hot water output of the air cooler (40) with an input of the pump (42) and an output of the pump (42) is connected with an input (A) of the valve (44) and that an output (AB) of the valve (44) is connected with an input of the water cooler (46).</claim-text> <claim-text>13. Heat exchanger according to any of the preceding claims, characterised in that the water circuit is supplied with electric energy by an emergency power generator.</claim-text> <claim-text>14. Heat exchanger according to any of the preceding claims, characterised in that the valve (44) is connected with a thermostat (48) which has a temperature sensor (50) arranged between the air cooler (40) and the input of the pump (42).</claim-text> <claim-text>15. Heat exchanger according to any of the preceding claims, characterised in that, in the heat exchanger (44), preferably in the accumulator medium (52), a thermostat, preferably a mechanical pressurised gas sensor, is arranged by means of which the refrigeration circuit (12) can be switched off at a specified temperature.</claim-text> <claim-text>16. Heat exchanger according to any of the preceding claims, characterised in that the charging heat exchanger (32, 100) and the discharging heat exchanger (46, 98) and/or the fins (94, 174) are made from copper or contain copper.</claim-text> <claim-text>17. Air conditioning system (10), comprising a primary charging circuit (12) designed as a refrigerant circuit which is coupled with a secondary discharging circuit (16) via a heat exchanger (14) having an accumulator medium (52), characterised in that the heat exchanger (14) is designed as a buffer accumulator and detachably connected with the charging circuit (12), that the discharging circuit (16) has a water cooler (46) embedded in the accumulator medium (52) of the heat exchanger (14), an air cooler (40) for cooling a power pack and a pump (42) and a valve (44), wherein the air cooler (40), the pump (16) and the valve (44) are connected with an emergency power supply unit, so that the water circuit (16) can function independently after uncoupling the heat exchanger (14) from the cooling circuit (12).</claim-text> <claim-text>18. Air conditioning system according to claim 17, characterised in that the valve (44) is designed as a three-way valve, wherein an input (A) of the valve (44) is connected with an output of the pump (42), an output (AB) of the pump is connected with an input of the water cooler (46) and an output (B) of the valve (44) is connected with an output of the water cooler (46) and a cold water connection of the air cooler (40).</claim-text> <claim-text>19. Air conditioning system according to claim 17 or 18, characterised in that the three-way valve (44) is controlled by means of a thermostat (48).</claim-text> <claim-text>20. Air conditioning system according to at least one of the claims 17 to 19, characterised in that, in the accumulator medium (52), a thermostat is arranged by means of which the refrigeration circuit (12) can be switched off when a predetermined temperature is reached.</claim-text> <claim-text>21. A heat exchanger substantially as described, with reference to the drawings, hereinbefore.</claim-text> <claim-text>22. An air conditioning system substantially as described, with reference to the drawings, hereinbef ore.</claim-text>