Refrigeration cycle

Abstract

A refrigeration cycle is a refrigeration cycle using a mixed refrigerant which is a flammable refrigerant and which contains at least 1,2-difluoroethylene (HFO-1132(E)), and includes a compressor ( 1 ), a heat-source-side heat exchanger ( 3 ), an expansion mechanism ( 4 ), a use-side heat exchanger ( 2 ), and a decompression mechanism ( 7 ). The decompression mechanism ( 7 ) decompresses, between an inlet and an outlet of the heat-source-side heat exchanger ( 3 ), the mixed refrigerant flowing through the heat-source-side heat exchanger ( 3 ) that functions as an evaporator.

1 . A refrigeration cycle using a refrigerant which is a flammable refrigerant and which contains at least 1,2-difluoroethylene (HFO-1132(E)), comprising:
 a compressor;   a heat-source-side heat exchanger;   an expansion mechanism;   a use-side heat exchanger; and   a decompression mechanism that decompresses, between an inlet and an outlet of the heat-source-side heat exchanger, the mixed refrigerant flowing through the heat-source-side heat exchanger that functions as an evaporator.   
     
     
         2 . The refrigeration cycle according to  claim 1 , wherein
 the decompression mechanism decompresses the refrigerant flowing through the heat-source-side heat exchanger in accordance with a temperature gradient of the refrigerant.   
     
     
         3 . The refrigeration cycle according to  claim 1 , wherein
 the heat-source-side heat exchanger includes a first heat exchange section and a second heat exchange section, and   the decompression mechanism is disposed between the first heat exchange section and the second heat exchange section.   
     
     
         4 . The refrigeration cycle according to  claim 1 , wherein
 the use-side heat exchanger is disposed in a use unit, and includes a third heat exchange section located on a front-surface side of the use unit, and a fourth heat exchange section located on a rear-surface side of the use unit,   an upper portion of the fourth heat exchange section is located near an upper portion of the third heat exchange section,   the third heat exchange section extends obliquely downward from the upper portion thereof toward the front-surface side of the use unit,   the fourth heat exchange section extends obliquely downward from the upper portion thereof toward the rear-surface side of the use unit, and   a capacity of a refrigerant flow path of the third heat exchange section is larger than a capacity of a refrigerant flow path of the fourth heat exchange section.   
     
     
         5 . The refrigeration cycle according to  claim 1 ,
 wherein   the refrigerant comprises trans-1,2-difluoroethylene (HFO-1132(E)), trifluoroethylene (HFO-1123), and 2,3,3,3-tetrafluoro-1-propene (R1234yf).   
     
     
         6 . The refrigeration cycle according to  claim 5 ,
 wherein   when the mass % of HFO-1132(E), HFO-1123, and R1234yf based on their sum in the refrigerant is respectively represented by x, y, and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), HFO-1123, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments AA′, A′B, BD, DC′, C′C, CO, and OA that connect the following 7 points:   
       point A (68.6, 0.0, 31.4), 
       point A′ (30.6, 30.0, 39.4), 
       point B (0.0, 58.7, 41.3), 
       point D (0.0, 80.4, 19.6), 
       point C′ (19.5, 70.5, 10.0), 
       point C (32.9, 67.1, 0.0), and 
       point O (100.0, 0.0, 0.0), 
       or on the above line segments (excluding the points on the line segments BD, CO, and OA);
 the line segment AA′ is represented by coordinates (x, 0.0016x 2 −0.9473x+57.497, −0.0016x 2 −0.0527x+42.503), 
 the line segment A′B is represented by coordinates (x, 0.0029x 2 −1.0268x+58.7, −0.0029x 2 +0.0268x+41.3), 
 the line segment DC′ is represented by coordinates (x, 0.0082x 2 −0.6671x+80.4, −0.0082x 2 −0.3329x+19.6), 
 the line segment C′C is represented by coordinates (x, 0.0067x 2 −0.6034x+79.729, −0.0067x 2 −0.3966x+20.271), and 
 the line segments BD, CO, and OA are straight lines. 
 
     
     
         7 . The refrigeration cycle according to  claim 5 ,
 wherein   when the mass % of HFO-1132(E), HFO-1123, and R1234yf based on their sum in the refrigerant is respectively represented by x, y, and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), HFO-1123, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments GI, IA, AA′, A′B, BD, DC′, C′C, and CG that connect the following 8 points:   
       point G (72.0, 28.0, 0.0), 
       point I (72.0, 0.0, 28.0), 
       point A (68.6, 0.0, 31.4), 
       point A′ (30.6, 30.0, 39.4), 
       point B (0.0, 58.7, 41.3), 
       point D (0.0, 80.4, 19.6), 
       point C′ (19.5, 70.5, 10.0), and 
       point C (32.9, 67.1, 0.0), 
       or on the above line segments (excluding the points on the line segments IA, BD, and CG);
 the line segment AA′ is represented by coordinates (x, 0.0016x 2 −0.9473x+57.497, −0.0016x 2 −0.0527x+42.503), 
 the line segment A′B is represented by coordinates (x, 0.0029x 2 −1.0268x+58.7, −0.0029x 2 +0.0268x+41.3), 
 the line segment DC′ is represented by coordinates (x, 0.0082x 2 −0.6671x+80.4, −0.0082x 2 −0.3329x+19.6), 
 the line segment C′C is represented by coordinates (x, 0.0067x 2 −0.6034x+79.729, −0.0067x 2 −0.3966x+20.271), and 
 the line segments GI, IA, BD, and CG are straight lines. 
 
     
     
         8 . The refrigeration cycle according to  claim 5 ,
 wherein   when the mass % of HFO-1132(E), HFO-1123, and R1234yf based on their sum in the refrigerant is respectively represented by x, y, and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), HFO-1123, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments JP, PN, NK, KA′, A′B, BD, DC′, C′C, and CJ that connect the following 9 points:   
       point J (47.1, 52.9, 0.0), 
       point P (55.8, 42.0, 2.2), 
       point N (68.6, 16.3, 15.1), 
       point K (61.3, 5.4, 33.3), 
       point A′ (30.6, 30.0, 39.4), 
       point B (0.0, 58.7, 41.3), 
       point D (0.0, 80.4, 19.6), 
       point C′ (19.5, 70.5, 10.0), and 
       point C (32.9, 67.1, 0.0), 
       or on the above line segments (excluding the points on the line segments BD and CJ);
 the line segment PN is represented by coordinates (x, −0.1135x 2 +12.112x−280.43, 0.1135x 2 −13.112x+380.43), 
 the line segment NK is represented by coordinates (x, 0.2421x 2 −29.955x+931.91, −0.2421x 2 +28.955x−831.91), 
 the line segment KA′ is represented by coordinates (x, 0.0016x 2 −0.9473x+57.497, −0.0016x 2 −0.0527x+42.503), 
 the line segment A′B is represented by coordinates (x, 0.0029x 2 −1.0268x+58.7, −0.0029x 2 +0.0268x+41.3), 
 the line segment DC′ is represented by coordinates (x, 0.0082x 2 −0.6671x+80.4, −0.0082x 2 −0.3329x+19.6), 
 the line segment C′C is represented by coordinates (x, 0.0067x 2 −0.6034x+79.729, −0.0067x 2 −0.3966x+20.271), and 
 the line segments JP, BD, and CG are straight lines. 
 
     
     
         9 . The refrigeration cycle according to  claim 5 ,
 wherein   when the mass % of HFO-1132(E), HFO-1123, and R1234yf based on their sum in the refrigerant is respectively represented by x, y, and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), HFO-1123, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments JP, PL, LM, MA′, A′B, BD, DC′, C′C, and CJ that connect the following 9 points:   
       point J (47.1, 52.9, 0.0), 
       point P (55.8, 42.0, 2.2), 
       point L (63.1, 31.9, 5.0), 
       point M (60.3, 6.2, 33.5), 
       point A′ (30.6, 30.0, 39.4), 
       point B (0.0, 58.7, 41.3), 
       point D (0.0, 80.4, 19.6), 
       point C′ (19.5, 70.5, 10.0), and 
       point C (32.9, 67.1, 0.0), 
       or on the above line segments (excluding the points on the line segments BD and CJ);
 the line segment PL is represented by coordinates (x, −0.1135x 2 +12.112x−280.43, 0.1135x 2 −13.112x+380.43) 
 the line segment MA′ is represented by coordinates (x, 0.0016x 2 −0.9473x+57.497, −0.0016x 2 −0.0527x+42.503), 
 the line segment A′B is represented by coordinates (x, 0.0029x 2 −1.0268x+58.7, −0.0029x 2 +0.0268x+41.3), 
 the line segment DC′ is represented by coordinates (x, 0.0082x 2 −0.6671x+80.4, −0.0082x 2 −0.3329x+19.6), 
 the line segment C′C is represented by coordinates (x, 0.0067x 2 −0.6034x+79.729, −0.0067x 2 −0.3966x+20.271), and 
 the line segments JP, LM, BD, and CG are straight lines. 
 
     
     
         10 . The refrigeration cycle according to  claim 5 ,
 wherein   when the mass % of HFO-1132(E), HFO-1123, and R1234yf based on their sum in the refrigerant is respectively represented by x, y, and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), HFO-1123, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments PL, LM, MA′, A′B, BF, FT, and TP that connect the following 7 points:   
       point P (55.8, 42.0, 2.2), 
       point L (63.1, 31.9, 5.0), 
       point M (60.3, 6.2, 33.5), 
       point A′ (30.6, 30.0, 39.4), 
       point B (0.0, 58.7, 41.3), 
       point F (0.0, 61.8, 38.2), and 
       point T (35.8, 44.9, 19.3), 
       or on the above line segments (excluding the points on the line segment BF);
 the line segment PL is represented by coordinates (x, −0.1135x 2 +12.112x−280.43, 0.1135x 2 −13.112x+380.43), 
 the line segment MA′ is represented by coordinates (x, 0.0016x 2 −0.9473x+57.497, −0.0016x 2 −0.0527x+42.503), 
 the line segment A′B is represented by coordinates (x, 0.0029x 2 −1.0268x+58.7, −0.0029x 2 +0.0268x+41.3), 
 the line segment FT is represented by coordinates (x, 0.0078x 2 −0.7501x+61.8, −0.0078x 2 −0.2499x+38.2), 
 the line segment TP is represented by coordinates (x, 0.00672x 2 −0.7607x+63.525, −0.00672x 2 −0.2393x+36.475), and 
 the line segments LM and BF are straight lines. 
 
     
     
         11 . The refrigeration cycle according to  claim 5 ,
 wherein   when the mass % of HFO-1132(E), HFO-1123, and R1234yf based on their sum in the refrigerant is respectively represented by x, y, and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), HFO-1123, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments PL, LQ, QR, and RP that connect the following 4 points:   
       point P (55.8, 42.0, 2.2), 
       point L (63.1, 31.9, 5.0), 
       point Q (62.8, 29.6, 7.6), and 
       point R (49.8, 42.3, 7.9), 
       or on the above line segments;
 the line segment PL is represented by coordinates (x, −0.1135x 2 +12.112x−280.43, 0.1135x 2 −13.112x+380.43), 
 the line segment RP is represented by coordinates (x, 0.00672x 2 −0.7607x+63.525, −0.00672x 2 −0.2393x+36.475), and 
 the line segments LQ and QR are straight lines. 
 
     
     
         12 . The refrigeration cycle according to  claim 5 ,
 wherein   when the mass % of HFO-1132(E), HFO-1123, and R1234yf based on their sum in the refrigerant is respectively represented by x, y, and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), HFO-1123, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments SM, MA′, A′B, BF, FT, and TS that connect the following 6 points:   
       point S (62.6, 28.3, 9.1), 
       point M (60.3, 6.2, 33.5), 
       point A′ (30.6, 30.0, 39.4), 
       point B (0.0, 58.7, 41.3), 
       point F (0.0, 61.8, 38.2), and 
       point T (35.8, 44.9, 19.3), 
       or on the above line segments,
 the line segment MA′ is represented by coordinates (x, 0.0016x 2 −0.9473x+57.497, −0.0016x 2 −0.0527x+42.503), 
 the line segment A′B is represented by coordinates (x, 0.0029x 2 −1.0268x+58.7, −0.0029x 2 +0.0268x+41.3), 
 the line segment FT is represented by coordinates (x, 0.0078x 2 −0.7501x+61.8, −0.0078x 2 −0.2499x+38.2), 
 the line segment TS is represented by coordinates (x, −0.0017x 2 −0.7869x+70.888, −0.0017x 2 −0.2131x+29.112), and 
 the line segments SM and BF are straight lines. 
 
     
     
         13 . The refrigeration cycle according to  claim 1 ,
 wherein   the refrigerant comprises trans-1,2-difluoroethylene (HFO-1132(E)) and trifluoroethylene (HFO-1123) in a total amount of 99.5 mass % or more based on the entire refrigerant, and   the refrigerant comprises 62.0 mass % to 72.0 mass % of HFO-1132(E) based on the entire refrigerant.   
     
     
         14 . The refrigeration cycle according to  claim 1 ,
 wherein   the refrigerant comprises trans-1,2-difluoroethylene (HFO-1132(E)) and trifluoroethylene (HFO-1123) in a total amount of 99.5 mass % or more based on the entire refrigerant, and   the refrigerant comprises 45.1 mass % to 47.1 mass % of HFO-1132(E) based on the entire refrigerant.   
     
     
         15 . The refrigeration cycle according to  claim 1 ,
 wherein   the refrigerant comprises trans-1,2-difluoroethylene (HFO-1132(E)), trifluoroethylene (HFO-1123), 2,3,3,3-tetrafluoro-1-propene (R1234yf), and difluoromethane (R32),   
       wherein
 when the mass % of HFO-1132(E), HFO-1123, R1234yf, and R32 based on their sum in the refrigerant is respectively represented by x, y, z, and a, 
 if 0<a≤11.1, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), HFO-1123, and R1234yf is (100−a) mass % are within the range of a figure surrounded by straight lines GI, IA, AB, BD′, D′ C, and CG that connect the following 6 points: 
 
       point G (0.026a 2 −1.7478a+72.0, −0.026a 2 +0.7478a+28.0, 0.0), 
       point I (0.026a 2 −1.7478a+72.0, 0.0, −0.026a 2 +0.7478a+28.0), 
       point A (0.0134a 2 −1.9681a+68.6, 0.0, −0.0134a 2 +0.9681a+31.4), 
       point B (0.0, 0.0144a 2 −1.6377a+58.7, −0.0144a 2 +0.6377a+41.3), 
       point D′ (0.0, 0.0224a 2 +0.968a+75.4, −0.0224a 2 −1.968a+24.6), and 
       point C (−0.2304a 2 −0.4062a+32.9, 0.2304a 2 −0.5938a+67.1, 0.0), 
       or on the straight lines GI, AB, and D′C (excluding point G, point I, point A, point B, point D′, and point C);
 if 11.1<a≤18.2, coordinates (x,y,z) in the ternary composition diagram are within the range of a figure surrounded by straight lines GI, IA, AB, BW, and WG that connect the following 5 points: 
 
       point G (0.02a 2 −1.6013a+71.105, −0.02a 2 +0.6013a+28.895, 0.0), 
       point I (0.02a 2 −1.6013a+71.105, 0.0, −0.02a 2 +0.6013a+28.895), 
       point A (0.0112a 2 −1.9337a+68.484, 0.0, −0.0112a 2 +0.9337a+31.516), 
       point B (0.0, 0.0075a 2 −1.5156a+58.199, −0.0075a 2 +0.5156a+41.801), and 
       point W (0.0, 100.0−a, 0.0), 
       or on the straight lines GI and AB (excluding point G, point I, point A, point B, and point W);
 if 18.2<a≤26.7, coordinates (x,y,z) in the ternary composition diagram are within the range of a figure surrounded by straight lines GI, IA, AB, BW, and WG that connect the following 5 points: 
 
       point G (0.0135a 2 −1.4068a+69.727, −0.0135a 2 +0.4068a+30.273, 0.0), 
       point I (0.0135a 2 −1.4068a+69.727, 0.0, −0.0135a 2 +0.4068a+30.273), 
       point A (0.0107a 2 −1.9142a+68.305, 0.0, −0.0107a 2 +0.9142a+31.695), 
       point B (0.0, 0.009a 2 −1.6045a+59.318, −0.009a 2 +0.6045a+40.682), and 
       point W (0.0, 100.0−a, 0.0), 
       or on the straight lines GI and AB (excluding point G, point I, point A, point B, and point W);
 if 26.7<a≤36.7, coordinates (x,y,z) in the ternary composition diagram are within the range of a figure surrounded by straight lines GI, IA, AB, BW, and WG that connect the following 5 points: 
 
       point G (0.0111a 2 −1.3152a+68.986, −0.0111a 2 +0.3152a+31.014, 0.0), 
       point I (0.0111a 2 −1.3152a+68.986, 0.0, −0.0111a 2 +0.3152a+31.014), 
       point A (0.0103a 2 −1.9225a+68.793, 0.0, −0.0103a 2 +0.9225a+31.207), 
       point B (0.0, 0.0046a 2 −1.41a+57.286, −0.0046a 2 +0.41a+42.714), and 
       point W (0.0, 100.0−a, 0.0), 
       or on the straight lines GI and AB (excluding point G, point I, point A, point B, and point W); and
 if 36.7<a≤46.7, coordinates (x,y,z) in the ternary composition diagram are within the range of a figure surrounded by straight lines GI, IA, AB, BW, and WG that connect the following 5 points: 
 
       point G (0.0061a 2 −0.9918a+63.902, −0.0061a 2 −0.0082a+36.098, 0.0), 
       point I (0.0061a 2 −0.9918a+63.902, 0.0, −0.0061a 2 −0.0082a+36.098), 
       point A (0.0085a 2 −1.8102a+67.1, 0.0, −0.0085a 2 +0.8102a+32.9), 
       point B (0.0, 0.0012a 2 −1.1659a+52.95, −0.0012a 2 +0.1659a+47.05), and 
       point W (0.0, 100.0−a, 0.0), 
       or on the straight lines GI and AB (excluding point G, point I, point A, point B, and point W). 
     
     
         16 . The refrigeration cycle according to  claim 1 ,
 wherein   the refrigerant comprises trans-1,2-difluoroethylene (HFO-1132(E)), trifluoroethylene (HFO-1123), 2,3,3,3-tetrafluoro-1-propene (R1234yf), and difluoromethane (R32),   wherein   when the mass % of HFO-1132(E), HFO-1123, R1234yf, and R32 based on their sum in the refrigerant is respectively represented by x, y, z, and a,   if 0<a≤11.1, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), HFO-1123, and R1234yf is (100−a) mass % are within the range of a figure surrounded by straight lines JK′, K′B, BD′, D′C, and CJ that connect the following 5 points:   
       point J (0.0049a 2 −0.9645a+47.1, −0.0049a 2 −0.0355a+52.9, 0.0), 
       point K′ (0.0514a 2 −2.4353a+61.7, −0.0323a 2 +0.4122a+5.9, −0.0191a 2 +1.0231a+32.4), 
       point B (0.0, 0.0144a 2 −1.6377a+58.7, −0.0144a 2 +0.6377a+41.3), 
       point D′ (0.0, 0.0224a 2 +0.968a+75.4, −0.0224a 2 −1.968a+24.6), and 
       point C (−0.2304a 2 −0.4062a+32.9, 0.2304a 2 −0.5938a+67.1, 0.0), 
       or on the straight lines JK′, K′B, and D′C (excluding point J, point B, point D′, and point C);
 if 11.1<a≤18.2, coordinates (x,y,z) in the ternary composition diagram are within the range of a figure surrounded by straight lines JK′, K′B, BW, and WJ that connect the following 4 points: 
 
       point J (0.0243a 2 −1.4161a+49.725, −0.0243a 2 +0.4161a+50.275, 0.0), 
       point K′ (0.0341a 2 −2.1977a+61.187, −0.0236a 2 +0.34a+5.636, −0.0105a 2 +0.8577a+33.177), 
       point B (0.0, 0.0075a 2 −1.5156a+58.199, −0.0075a 2 +0.5156a+41.801), and 
       point W (0.0, 100.0−a, 0.0), 
       or on the straight lines JK′ and K′B (excluding point J, point B, and point W);
 if 18.2<a≤26.7, coordinates (x,y,z) in the ternary composition diagram are within the range of a figure surrounded by straight lines JK′, K′B, BW, and WJ that connect the following 4 points: 
 
       point J (0.0246a 2 −1.4476a+50.184, −0.0246a 2 +0.4476a+49.816, 0.0), 
       point K′ (0.0196a 2 −1.7863a+58.515, −0.0079a 2 −0.1136a+8.702, −0.0117a 2 +0.8999a+32.783), 
       point B (0.0, 0.009a 2 −1.6045a+59.318, −0.009a 2 +0.6045a+40.682), and 
       point W (0.0, 100.0−a, 0.0), 
       or on the straight lines JK′ and K′B (excluding point J, point B, and point W);
 if 26.7<a≤36.7, coordinates (x,y,z) in the ternary composition diagram are within the range of a figure surrounded by straight lines JK′, K′A, AB, BW, and WJ that connect the following 5 points: 
 
       point J (0.0183a 2 −1.1399a+46.493, −0.0183a 2 +0.1399a+53.507, 0.0), 
       point K′ (−0.0051a 2 +0.0929a+25.95, 0.0, 0.0051a 2 −1.0929a+74.05), 
       point A (0.0103a 2 −1.9225a+68.793, 0.0, −0.0103a 2 +0.9225a+31.207), 
       point B (0.0, 0.0046a 2 −1.41a+57.286, −0.0046a 2 +0.41a+42.714), and 
       point W (0.0, 100.0−a, 0.0), 
       or on the straight lines JK′, K′A, and AB (excluding point J, point B, and point W); and
 if 36.7<a≤46.7, coordinates (x,y,z) in the ternary composition diagram are within the range of a figure surrounded by straight lines JK′, K′A, AB, BW, and WJ that connect the following 5 points: 
 
       point J (−0.0134a 2 +1.0956a+7.13, 0.0134a 2 −2.0956a+92.87, 0.0), 
       point K′ (−1.892a+29.443, 0.0, 0.892a+70.557), 
       point A (0.0085a 2 −1.8102a+67.1, 0.0, −0.0085a 2 +0.8102a+32.9), 
       point B (0.0, 0.0012a 2 −1.1659a+52.95, −0.0012a 2 +0.1659a+47.05), and 
       point W (0.0, 100.0−a, 0.0), 
       or on the straight lines JK′, K′A, and AB (excluding point J, point B, and point W). 
     
     
         17 . The refrigeration cycle according to  claim 1 ,
 wherein   the refrigerant comprises trans-1,2-difluoroethylene (HFO-1132(E)), difluoromethane (R32), and 2,3,3,3-tetrafluoro-1-propene (R1234yf), wherein   when the mass % of HFO-1132(E), R32, and R1234yf based on their sum in the refrigerant is respectively represented by x, y, and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), R32, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments IJ, JN, NE, and EI that connect the following 4 points:   
       point I (72.0, 0.0, 28.0), 
       point J (48.5, 18.3, 33.2), 
       point N (27.7, 18.2, 54.1), and 
       point E (58.3, 0.0, 41.7), 
       or on these line segments (excluding the points on the line segment EI;
 the line segment IJ is represented by coordinates (0.0236y 2 −1.7616y+72.0, y, −0.0236y 2 +0.7616y+28.0); 
 the line segment NE is represented by coordinates (0.012y 2 −1.9003y+58.3, y, −0.012y 2 +0.9003y+41.7); and 
 the line segments JN and EI are straight lines. 
 
     
     
         18 . The refrigeration cycle according to  claim 1 ,
 wherein   the refrigerant comprises trans-1,2-difluoroethylene (HFO-1132(E)), difluoromethane (R32), and 2,3,3,3-tetrafluoro-1-propene (R1234yf), wherein   when the mass % of HFO-1132(E), R32, and R1234yf based on their sum in the refrigerant is respectively represented by x, y, and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), R32, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments MM′, MN, NV, VG, and GM that connect the following 5 points:   
       point M (52.6, 0.0, 47.4), 
       point M′(39.2, 5.0, 55.8), 
       point N (27.7, 18.2, 54.1), 
       point V (11.0, 18.1, 70.9), and 
       point G (39.6, 0.0, 60.4), 
       or on these line segments (excluding the points on the line segment GM);
 the line segment MM′ is represented by coordinates (0.132y 2 −3.34y+52.6, y, −0.132y 2 +2.34y+47.4); 
 the line segment M′N is represented by coordinates (0.0596y 2 −2.2541y+48.98, y, −0.0596y 2 +1.2541y+51.02); 
 the line segment VG is represented by coordinates (0.0123y 2 −1.8033y+39.6, y, −0.0123y 2 +0.8033y+60.4); and 
 the line segments NV and GM are straight lines. 
 
     
     
         19 . The refrigeration cycle according to  claim 1 ,
 wherein   the refrigerant comprises trans-1,2-difluoroethylene (HFO-1132(E)), difluoromethane (R32), and 2,3,3,3-tetrafluoro-1-propene (R1234yf),   
       wherein
 when the mass % of HFO-1132(E), R32, and R1234yf based on their sum in the refrigerant is respectively represented by x, y and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), R32, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments ON, NU, and UO that connect the following 3 points: 
 
       point O (22.6, 36.8, 40.6), 
       point N (27.7, 18.2, 54.1), and 
       point U (3.9, 36.7, 59.4), 
       or on these line segments;
 the line segment ON is represented by coordinates (0.0072y 2 −0.6701y+37.512, y, −0.0072y 2 −0.3299y+62.488); 
 the line segment NU is represented by coordinates (0.0083y 2 −1.7403y+56.635, y, −0.0083y 2 +0.7403y+43.365); and 
 the line segment UO is a straight line. 
 
     
     
         20 . The refrigeration cycle according to  claim 1 ,
 wherein   the refrigerant comprises trans-1,2-difluoroethylene (HFO-1132(E)), difluoromethane (R32), and 2,3,3,3-tetrafluoro-1-propene (R1234yf),   
       wherein
 when the mass % of HFO-1132(E), R32, and R1234yf based on their sum in the refrigerant is respectively represented by x, y, and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), R32, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments QR, RT, TL, LK, and KQ that connect the following 5 points: 
 
       point Q (44.6, 23.0, 32.4), 
       point R (25.5, 36.8, 37.7), 
       point T (8.6, 51.6, 39.8), 
       point L (28.9, 51.7, 19.4), and 
       point K (35.6, 36.8, 27.6), 
       or on these line segments;
 the line segment QR is represented by coordinates (0.0099y 2 −1.975y+84.765, y, −0.0099y 2 +0.975y+15.235); 
 the line segment RT is represented by coordinates (0.0082y 2 −1.8683y+83.126, y, −0.0082y 2 +0.8683y+16.874); 
 the line segment LK is represented by coordinates (0.0049y 2 −0.8842y+61.488, y, −0.0049y 2 −0.1158y+38.512); 
 the line segment KQ is represented by coordinates (0.0095y 2 −1.2222y+67.676, y, −0.0095y 2 +0.2222y+32.324); and 
 the line segment TL is a straight line. 
 
     
     
         21 . The refrigeration cycle according to  claim 1 ,
 wherein   the refrigerant comprises trans-1,2-difluoroethylene (HFO-1132(E)), difluoromethane (R32), and 2,3,3,3-tetrafluoro-1-propene (R1234yf),   
       wherein
 when the mass % of HFO-1132(E), R32, and R1234yf based on their sum in the refrigerant is respectively represented by x, y, and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), R32, and R1234yf is 100 mass % are within the range of a figure surrounded by line segments PS, ST, and TP that connect the following 3 points: 
 
       point P (20.5, 51.7, 27.8), 
       point S (21.9, 39.7, 38.4), and 
       point T (8.6, 51.6, 39.8), 
       or on these line segments;
 the line segment PS is represented by coordinates (0.0064y 2 −0.7103y+40.1, y, −0.0064y 2 −0.2897y+59.9); 
 the line segment ST is represented by coordinates (0.0082y 2 −1.8683y+83.126, y, −0.0082y 2 +0.8683y+16.874); and 
 the line segment TP is a straight line. 
 
     
     
         22 . The refrigeration cycle according to  claim 1 ,
 wherein   the refrigerant comprises trans-1,2-difluoroethylene (HFO-1132(E)), trifluoroethylene (HFO-1123), and difluoromethane (R32),   
       wherein
 when the mass % of HFO-1132(E), HFO-1123, and R32 based on their sum in the refrigerant is respectively represented by x, y, and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), HFO-1123, and R32 is 100 mass % are within the range of a figure surrounded by line segments IK, KB′, B′H, HR, RG, and GI that connect the following 6 points: 
 
       point I (72.0, 28.0, 0.0), 
       point K (48.4, 33.2, 18.4), 
       point B′ (0.0, 81.6, 18.4), 
       point H (0.0, 84.2, 15.8), 
       point R (23.1, 67.4, 9.5), and 
       point G (38.5, 61.5, 0.0), 
       or on these line segments (excluding the points on the line segments B′H and GI);
 the line segment IK is represented by coordinates (0.025z 2 −1.7429z+72.00, −0.025z 2 +0.7429z+28.0, z), 
 the line segment HR is represented by coordinates (−0.3123z 2 +4.234z+11.06, 0.3123z 2 −5.234z+88.94, z), 
 the line segment RG is represented by coordinates (−0.0491z 2 −1.1544z+38.5, 0.0491z 2 +0.1544z+61.5, z), and 
 the line segments KB′ and GI are straight lines. 
 
     
     
         23 . The refrigeration cycle according to  claim 1 ,
 wherein   the refrigerant comprises trans-1,2-difluoroethylene (HFO-1132(E)), trifluoroethylene (HFO-1123), and difluoromethane (R32),   
       wherein
 when the mass % of HFO-1132(E), HFO-1123, and R32 based on their sum in the refrigerant is respectively represented by x, y, and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), HFO-1123, and R32 is 100 mass % are within the range of a figure surrounded by line segments IJ, JR, RG, and GI that connect the following 4 points: 
 
       point I (72.0, 28.0, 0.0), 
       point J (57.7, 32.8, 9.5), 
       point R (23.1, 67.4, 9.5), and 
       point G (38.5, 61.5, 0.0), 
       or on these line segments (excluding the points on the line segment GI);
 the line segment IJ is represented by coordinates (0.025z 2 −1.7429z+72.0, −0.025z 2 +0.7429z+28.0, z), 
 the line segment RG is represented by coordinates (−0.0491z 2 −1.1544z+38.5, 0.0491z 2 +0.1544z+61.5, z), and 
 the line segments JR and GI are straight lines. 
 
     
     
         24 . The refrigeration cycle according to  claim 1 ,
 wherein   the refrigerant comprises trans-1,2-difluoroethylene (HFO-1132(E)), trifluoroethylene (HFO-1123), and difluoromethane (R32),   
       wherein
 when the mass % of HFO-1132(E), HFO-1123, and R32 based on their sum in the refrigerant is respectively represented by x, y, and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), HFO-1123, and R32 is 100 mass % are within the range of a figure surrounded by line segments MP, PB′, B′H, HR, RG, and GM that connect the following 6 points: 
 
       point M (47.1, 52.9, 0.0), 
       point P (31.8, 49.8, 18.4), 
       point B′ (0.0, 81.6, 18.4), 
       point H (0.0, 84.2, 15.8), 
       point R (23.1, 67.4, 9.5), and 
       point G (38.5, 61.5, 0.0), 
       or on these line segments (excluding the points on the line segments B′H and GM);
 the line segment MP is represented by coordinates (0.0083z 2 −0.984z+47.1, −0.0083z 2 −0.016z+52.9, z), 
 the line segment HR is represented by coordinates (−0.3123z 2 +4.234z+11.06, 0.3123z 2 −5.234z+88.94, z), 
 the line segment RG is represented by coordinates (−0.0491z 2 −1.1544z+38.5, 0.0491z 2 +0.1544z+61.5, z), and 
 the line segments PB′ and GM are straight lines. 
 
     
     
         25 . The refrigeration cycle according to  claim 1 ,
 wherein   the refrigerant comprises trans-1,2-difluoroethylene (HFO-1132(E)), trifluoroethylene (HFO-1123), and difluoromethane (R32),   
       wherein
 when the mass % of HFO-1132(E), HFO-1123, and R32 based on their sum in the refrigerant is respectively represented by x, y, and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), HFO-1123, and R32 is 100 mass % are within the range of a figure surrounded by line segments MN, NR, RG, and GM that connect the following 4 points: 
 
       point M (47.1, 52.9, 0.0), 
       point N (38.5, 52.1, 9.5), 
       point R (23.1, 67.4, 9.5), and 
       point G (38.5, 61.5, 0.0), 
       or on these line segments (excluding the points on the line segment GM);
 the line segment MN is represented by coordinates (0.0083z 2 −0.984z+47.1, −0.0083z 2 −0.016z+52.9, z), 
 the line segment RG is represented by coordinates (−0.0491z 2 −1.1544z+38.5, 0.0491z 2 +0.1544z+61.5, z), and 
 the line segments JR and GI are straight lines. 
 
     
     
         26 . The refrigeration cycle according to  claim 1 ,
 wherein   the refrigerant comprises trans-1,2-difluoroethylene (HFO-1132(E)), trifluoroethylene (HFO-1123), and difluoromethane (R32),   
       wherein
 when the mass % of HFO-1132(E), HFO-1123, and R32 based on their sum in the refrigerant is respectively represented by x, y, and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), HFO-1123, and R32 is 100 mass % are within the range of a figure surrounded by line segments PS, ST, and TP that connect the following 3 points: 
 
       point P (31.8, 49.8, 18.4), 
       point S (25.4, 56.2, 18.4), and 
       point T (34.8, 51.0, 14.2), 
       or on these line segments;
 the line segment ST is represented by coordinates (−0.0982z 2 +0.9622z+40.931, 0.0982z 2 −1.9622z+59.069, z), 
 the line segment TP is represented by coordinates (0.0083z 2 −0.984z+47.1, −0.0083z 2 −0.016z+52.9, z), and 
 the line segment PS is a straight line. 
 
     
     
         27 . The refrigeration cycle according to  claim 1 ,
 wherein   the refrigerant comprises trans-1,2-difluoroethylene (HFO-1132(E)), trifluoroethylene (HFO-1123), and difluoromethane (R32),   
       wherein
 when the mass % of HFO-1132(E), HFO-1123, and R32 based on their sum in the refrigerant is respectively represented by x, y, and z, coordinates (x,y,z) in a ternary composition diagram in which the sum of HFO-1132(E), HFO-1123, and R32 is 100 mass % are within the range of a figure surrounded by line segments QB″, B″D, DU, and UQ that connect the following 4 points: 
 
       point Q (28.6, 34.4, 37.0), 
       point B″ (0.0, 63.0, 37.0), 
       point D (0.0, 67.0, 33.0), and 
       point U (28.7, 41.2, 30.1), 
       or on these line segments (excluding the points on the line segment B″D);
 the line segment DU is represented by coordinates (−3.4962z 2 +210.71z−3146.1, 3.4962z 2 −211.71z+3246.1, z), 
 the line segment UQ is represented by coordinates (0.0135z 2 −0.9181z+44.133, −0.0135z 2 −0.0819z+55.867, z), and 
 the line segments QB″ and B″D are straight lines.