Refrigerant Comprising Methane, And Refrigeration System And Cabinet With Such Refrigerant

Abstract

The invention relates to a refrigerant for use in a single-stage or auto cascade refrigeration system. The refrigerant comprises a mixture of gasses of at least three different hydrocarbons. The at least three different hydrocarbons include butane (C4H10), ethene (C2H4) and methane (CH4). The mixture of gasses comprises at the most 10% by weight of methane (CH4). The invention also relates to a refrigeration system with methane-containing refrigerant, to a refrigeration cabinet with methane-containing refrigerant and to use of a refrigeration cabinet with such refrigerant.

Claims

1. A refrigerant for use in a single-stage or auto cascade refrigeration system, the refrigerant comprising a mixture of gasses of at least three different hydrocarbons, wherein the at least three different hydrocarbons include butane (5 C4H10,R600), ethene (C2H4,R1150) and methane (CH4,R50), and wherein the mixture of gasses comprises between 1% and 6% by weight of methane (CH4,R50) of a total weight of the mixture of gasses.

2. A refrigerant according to claim 1, wherein the mixture of gasses comprises between 50% and 74% by weight of butane (C4H10,R600) of the total weight of the mixture of gasses.

3. The refrigerant according to claim 1, wherein the mixture of gasses comprises between 25% and 40% by weight of ethene (C2H4,R1150) of the total weight of the mixture of gasses.

4. The refrigerant according to claim 1, wherein the mixture of gasses comprises between 10% and 30% by weight of isobutane (C4H10,R600a) of the total weight of the mixture of gasses.

5. A refrigeration system comprising at least one compressor, at least one condenser, at least a first heat exchanger, at least one flow restriction, at least one evaporator all refrigeration components being interconnected serially in a refrigerant circuit, and which refrigeration system comprises mixture of gasses of at least three different hydrocarbons, including butane (C4H10,R600), ethene (C2H4,R1150) and methane (CH4,R50), wherein the mixture of gas comprises at the most 10% by weight of methane (CH4,R50) of a total weight of the mixture of gasses.

6. The refrigeration system according to claim 5, which refrigeration system is a single-stage or auto cascade refrigeration system, and wherein the mixture of gas comprises between 1% and 6% by weight of methane (CH4,R50) of the total weight of the mixture of gasses.

7. The refrigeration system according to claim 6, which refrigeration system is a single-stage or auto cascade refrigeration system, and wherein the mixture of gas comprises between 2% and 4% by weight of methane (CH4,R50) of the total weight of the mixture of gasses.

8. The refrigeration system according to claim 5, which refrigeration system is a single-stage or auto cascade refrigeration system, wherein the refrigeration 5 system is capable of refrigerating goods to a temperature between −40 and −90 degrees Celsius, and wherein the total weight of the mixture of gasses in the refrigeration circuit is at the most 150 grams.

9. The refrigeration system according to claim 5, wherein the refrigeration system is capable of refrigerating goods to a temperature between −40 and −90 degrees Celsius, and wherein the total weight of the mixture of gasses in the refrigeration circuit is at the most 200 grams.

10. The refrigeration system according to claim 5, wherein the refrigeration system is capable of refrigerating goods to a temperature between −40 and −90 degrees Celsius, and wherein the total weight of the mixture of gasses in the refrigeration circuit is at the most 250 grams.

11. The refrigeration system according to claim 5, wherein the refrigeration system is capable of refrigerating goods to a temperature between −40 and −90 degrees Celsius, and wherein the total weight of the mixture of gasses in the refrigeration circuit is at the most 300 grams, possibly at the most 500 grams.

12. The refrigeration system according to claim 5, which refrigeration system is a single-stage or auto cascade refrigeration system comprising an internal heat exchanger, which internal heat exchanger (IHX) is for evaporating at least part of the butane (C4H10,R600) and for condensing at least part of the ethene (C2H4,R1150) and/or methane (CH4,R50), and placed between a condenser and a non-internal heat exchanger (IHX) for goods to be cooled.

13. The refrigeration system according to claim 5, which refrigeration system comprises—a first single-stage or auto cascade refrigeration circuit with a set of first refrigeration components being at least one first compressor, at least one first condenser, at least a first heat exchanger, at least one first flow restriction and at least one first evaporator, all first refrigeration components being interconnected serially in a first refrigerant circuit, and—a second single-stage or auto cascade refrigeration circuit with a second set of at least one second compressor, at least one second condenser, at least one second heat exchanger, at least one second flow restriction and at least one second evaporator, all second refrigeration components being interconnected serially in a second refrigerant circuit, which second refrigeration circuit is separate from the first refrigeration circuit, and-which refrigeration components also comprises at least one first internal heat exchanger (IHX) is provided for evaporating at least part of the butane (C4H10,R600) and for condensing at least part of the ethene (C2H4,R1150) and/or for condensing at least part of the methane (CH4, R50), and where the at least one first internal heat exchanger (IHX) is placed between a condenser and a non-internal heat exchanger for goods to be cooled.

14. The refrigeration system according to claim 13, if isobutane (C4H10,R600a) is present in the refrigeration system, the at least one first internal heat exchanger (IHX) is provided for possibly evaporating at least part of the isobutane (C4H10,R600a).

15. A refrigeration cabinet for cooling of goods, the refrigeration apparatus comprising a single-stage or auto cascade refrigeration system comprising at least one compressor, at least one condenser, at least a first heat exchanger, at least one flow restriction and at least one evaporator, all refrigeration components being interconnected serially in a refrigerant circuit, and which refrigeration cabinet comprises mixture of gasses of at least three different hydrocarbons, including butane (C4H10,R600), ethene (C2H4,R1150) and methane (CH4,R50), wherein the mixture of gas comprises at the most 10% by weight of methane (CH4,R50) of the total weight of the mixture of gasses, and where at least one of the evaporators for cooling of goods, preferably a plurality of the evaporators for cooling of goods, possibly all of the evaporators for cooling of goods, are placed in shelves inside an interior of a chamber of the refrigeration cabinet, which shelves are for supporting goods to be cooled in the refrigeration cabinet.

16. The refrigeration cabinet according to claim 15, wherein the refrigeration cabinet has an interior volume of between 400 and 500 litres, with a cooling capacity of between −40 and −90 degrees Celsius, and wherein a total weight of mixture of gasses in at least one refrigeration circuit of the refrigeration cabinet is at the 5 most 150 grams.

17. The refrigeration cabinet according to claim 15, wherein the refrigeration cabinet has an interior volume of between 500 and 600 litres, with a cooling capacity of between −40 and −90 degrees Celsius, and wherein a total weight of mixture of gasses in at least one refrigeration circuit of the refrigeration cabinet is at the most 200 grams.

18. The refrigeration cabinet according to claim 15, wherein the refrigeration cabinet has an interior volume of between 600 and 700 litres, with a cooling capacity of between −40 and −90 degrees Celsius, and wherein a total weight of mixture of gasses in at least one refrigeration circuit of the refrigeration cabinet is at the most 250 grams.

19. The refrigeration cabinet according to claim 15, wherein the refrigeration cabinet has an interior volume of between 700 and 900 litres, possible between 700 and 1000 litres, with a cooling capacity of between −40 and −90 degrees Celsius, and wherein a total weight of mixture of gasses in at least one refrigeration circuit of the refrigeration cabinet is at the most 300 grams, possibly at the most 500 grams.

20. The refrigeration cabinet according to claim 15, which refrigeration cabinet comprises-a first set of first refrigeration components being at least one first compressor, at least one first condenser, at least a first heat exchanger, at least one first flow restriction and at least one first evaporator, all first refrigeration components being interconnected serially in a first refrigerant circuit, and-a second set of at least one second compressor, at least one second condenser, at least one second heat exchanger, at least one second flow restriction and at least one second evaporator, all second refrigeration components being interconnected serially in a second refrigerant circuit, which second refrigeration circuit is separate from the first refrigeration circuit, and—where at least the first set of refrigeration components also comprises at least one internal heat exchanger (IHX) for evaporating at least part of the butane (C4H10,R600) and for condensing at least part of the ethene (C2H4,R1150) and/or methane (CH4,R50), and placed between a condenser and a non-internal heat exchanger for goods to be cooled.

21. The refrigeration cabinet according to claim 20, where a total weight of mixture of gasses in the first refrigeration circuit is at the most 150 grams, 5 and where a total weight of mixture of gasses in the second refrigeration circuit is at the most 150 grams.

22. The refrigeration cabinet according to claim 20, where a total weight of mixture of gasses in the first refrigeration circuit is at the most 200 grams, and where a total weight of mixture of gasses in the second refrigeration circuit is at the most 200 grams.

23. The refrigeration cabinet according to claim 20, where a total weight of mixture of gasses in the first refrigeration circuit is at the most 250 grams, and where a total weight of mixture of gasses in the second refrigeration circuit is at the most 250 grams.

24. The refrigeration cabinet according to claim 20, where a total weight of mixture of gasses in the first refrigeration circuit is at the most 300 grams, and where a total weight of mixture of gasses in the second refrigeration circuit is at the most 300 grams.

25. The refriaeration cabinet according to claim 15, where at least one of the evaporators for cooling of goods is placed in a top of the interior of a chamber of the refrigeration cabinet.

26. The refrigeration cabinet according to claim 15, which refrigeration cabinet comprises at least one internal heat exchanger (IHX) for evaporating at least part of the butane (C4H10, R600) and for condensing at least part of the ethene (C2H4,R1150) and/or methane (CH4,R50).

27. The use of a refrigeration cabinet according to claim 15 for cooling of goods to a temperature between −40 and −90 degrees Celsius.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0037] FIG. 1 shows one embodiment of a refrigeration system according to the invention,

[0038] FIG. 2 shows another embodiment of a refrigeration system according to the invention,

[0039] FIG. 3 shows a more detailed view of the refrigeration system shown in FIG. 2.

[0040] FIG. 4 shows a refrigeration system comprising two refrigeration circuits.

DETAILED DESCRIPTION OF INVENTION

[0041] FIG. 1 shows a refrigeration system 2 which system comprises a compressor 4, which compressor has a pressure outlet connected to a tube 6, which tube 6 is connected to a condenser unit 8 which can be cooled by means of a blowing unit 10 and from which condensing unit a tube 12 leads high pressure refrigerant further to a coil 14. From the coil 14 where further condensing takes place, the refrigerant is flowing further into a receiver 16. Here from the refrigerant flows through a tube 18 towards a capillary tube 20 and further into an evaporator 22. The low pressure refrigerant from the evaporator is flowing back through a tube 24 to the inlet of the compressor 4.

[0042] Using the new mixture of refrigerants, it is possible by the refrigeration system 2 shown at FIG. 1 to achieve very low temperatures even by a single-stage or auto cascade refrigeration system. The different gasses evaporate at different temperatures. By mixing gasses with sufficient low boiling points with normal boiling points, it is possible to adjust the refrigerant constituted by the mixture of gasses more or less to a specific temperature. A highly effective refrigeration system for low temperature purposes can be achieved. This can lead to a very effective reduction in power consumption, even when reaching temperatures below −60° C.

[0043] FIG. 2 shows a refrigeration system for an ultra low temperature freezer. The refrigeration system 102 comprises a compressor 104. The compressor 104 has an outlet tube 106 connected through a condenser 108. The condenser is cooled by heat dissipating means such as a fan 110. From the condenser 108, a tube 112 leads to a coil 114. From the coil, the refrigerant is passed into a receiver 116. From the receiver 116, a tube 118 leads to an internal heat exchanger (IHX) 125.

[0044] The gas from the tube 118 exits the internal heat exchanger 125 through a tube 120. The tube 120 is connected to a capillary tube (not shown). From the capillary tube, a tube 122 leads to the first evaporator 122. A tube 130 leads to the next evaporator 132. From the evaporator 132, a tube 134 leads to an evaporator 136. From the evaporator 136, a tube 138 leads to a further evaporator 140. From the further evaporator, a tube 142 leads to the final evaporator 144. From the final evaporator 144, a return tube 146 leads to the internal heat exchanger (IHX) 125, from which internal heat exchanger 125, the return line continues along the tube 124 towards the suction inlet at the compressor 104. The internal heat exchanger 125 has a low-pressure side, where at least part of the butane is evaporated, and the internal heat exchanger 125 has a high-pressure side, where at least part of the ethene and/or methane is condensed.

[0045] Using the new mixture of gasses in a refrigeration system as shown in FIG. 2, temperatures as low as below −80 degrees Celsius may be obtained in an ultra low temperature freezer, and temperatures as low as −80 degrees Celsius can be obtained by a single compressor with very low power consumption. The low power consumption leads to low heat dissipation.

[0046] FIG. 3 shows an enlarged view of the upper part of FIG. 2. FIG. 3 shows a refrigeration system 202 comprising a compressor 204. The compressor 204 has an outlet 206 connected through a condenser 208, which is cooled by heat dissipating means 210 such as a fan. A tube 212 leads to a coil 214 for further condensation, from where the refrigerant is passed to a receiver 216. From the receiver, a tube 218 leads to an internal heat exchanger (IHX) 225. The internal heat exchanger (IHX) 225 has a low-pressure side where at least part of the butane is evaporated, and the internal heat exchanger 225 has a high-pressure side where at least part of the ethene and/or methane is condensed.

[0047] If the refrigeration system is part of a refrigeration cabinet, the internal heat exchanger 125,225 is preferably placed within insulation of the refrigeration cabinet. Thereby, the internal heat exchanger 125,225 is insulated from the surroundings, so that heat dissipation from the surroundings to the internal heat exchanger 125,225 is minimized.

[0048] The refrigerant leaves the internal heat exchanger (IHX) 225 through a tube 219 that leads to a flow restriction formed as a capillary tube 220 from which capillary tube the refrigerant flows through a tube 222 towards an evaporator 223. The refrigerant leaves the evaporator 223 through a tube 230 to further evaporators (not shown). The refrigerant returns from the evaporators through a tube 246 which is sent to the internal heat exchanger (IHX) 225. The refrigerant leaves the internal heat exchanger (IHX) 225 through a tube 224 that leads to the inlet of the compressor 204.

[0049] FIG. 4 shows a refrigeration system 2, which system comprises two refrigeration circuits. The two refrigeration circuits are separate from each other. Each of the two refrigeration circuits has a compressor 4, which compressor has a pressure outlet connected to a tube 6, which tube 6 is connected to a condenser unit 8 which can be cooled by means of a blowing unit 10 and from which condensing unit a tube 12 leads high pressure refrigerant further to a coil 14.

[0050] A first refrigeration circuit comprises a set of first evaporators and a second refrigeration circuit comprises a set of second evaporators. The first set of evaporators and the second set of evaporators are intended for being part of shelves in a refrigeration cabinet, the shelves made for supporting goods to be cooled in the refrigeration cabinet.

[0051] The first refrigeration circuit is arranged for obtaining a first refrigeration temperature and the second refrigeration circuit is arranged for obtaining a second refrigeration temperature, lower than the first refrigeration temperature. Also, the second refrigeration circuit may function as a back up refrigeration circuit to the first refrigeration circuit, if the first refrigeration circuit fails, and vice versa.

[0052] As example, a refrigerator of an interior capacity of 390 litres with a cooling temperature range between −40 and −90 degrees Celsius, the refrigerator has a dual circuit refrigeration system as shown in FIG. 4 and with a very limited amount of refrigerant, less than 150 g. Furthermore, the gas mixture comprises a very limited amount of isobutane (R600) and a very limited amount of methane (R50), only 2.0 weight percent of the total weight of gas mixture.

[0053] As example, a refrigerator of an interior capacity of 500 litres with a cooling temperature range between −40 and −90 degrees Celsius, the refrigerator has a dual circuit refrigeration system as shown in FIG. 4 and with a very limited amount of refrigerant, less than 200 g., only 190 g. Furthermore, the gas mixture comprises a very limited amount of methane (R50), only 2.1 weight percent of the total weight of gas mixture.

[0054] As example, a refrigerator of an interior capacity of 610 litres with a cooling temperature range between −40 and −90 degrees Celsius, the refrigerator has a dual circuit refrigeration system as shown in FIG. 4 and with a very limited amount of refrigerant, less than 250 g, only 200 g. Furthermore, the gas mixture comprises a very limited amount of methane (R50), only 2.8 weight percent of the total weight of gas mixture.

[0055] As example, a refrigerator of an interior capacity of 820 litres with a cooling temperature range between −40 and −90 degrees Celsius. The refrigerator has a dual circuit refrigeration system as shown in FIG. 4 and with a very limited amount of refrigerant, less than 300 g., only 270 g. Furthermore, the gas mixture comprises a very limited amount of methane (R50), only 2.2 weight percent of the total weight of gas mixture.