Warm-water generating apparatus

Abstract

A warm-water generating apparatus (1) uses, as a refrigerant, a mixed refrigerant containing at least 1,2-difluoroethylene (HFO-1132(E)). The warm-water generating apparatus (1) includes a compressor (21), a heat-source-side air heat exchanger (24), an expansion valve (23), and a use-side water heat exchanger (22). The water heat exchanger (22) causes the mixed refrigerant flowing therein and first water to exchange heat with each other to heat the first water.

1 . A warm-water generating apparatus using a refrigerant containing at least 1,2-difluoroethylene (HFO-1132(E)), comprising:
 a compressor;   a heat-source-side first heat exchanger;   an expansion mechanism; and   a use-side second heat exchanger,   wherein the second heat exchanger causes the refrigerant flowing therein and first water to exchange heat with each other to heat the first water.   
     
     
         2 . The warm-water generating apparatus according to  claim 1 , further comprising:
 a tank; and   a circulation flow path that allows the first water to circulate between the tank and the second heat exchanger.   
     
     
         3 . The warm-water generating apparatus according to  claim 1 , further comprising:
 a first circulation flow path that allows the first water heated by the second heat exchanger to circulate;   a second circulation flow path that is different from the first circulation flow path;   a third heat exchanger that causes the first water flowing through the first circulation flow path and second water flowing through the second circulation flow path to exchange heat with each other to heat the second water flowing through the second circulation flow path; and   a tank that stores the second water heated by the third heat exchanger.   
     
     
         4 . The warm-water generating apparatus according to  claim 1 , further comprising:
 a first circulation flow path that allows the first water heated by the second heat exchanger to circulate; and   a tank,   wherein a portion of the first circulation flow path is disposed in the tank and allows the first water flowing through the first circulation flow path and second water in the tank to exchange heat with each other to heat the second water in the tank.   
     
     
         5 . The warm-water generating apparatus according to  claim 1 , further comprising:
 a tank;   a first circulation flow path that allows the first water to circulate between the second heat exchanger and the tank;   a third heat exchanger;   a second circulation flow path that allows the first water to circulate between the third heat exchanger and the tank; and   a third flow path that is different from the first circulation flow path and the second circulation flow path,   wherein the third heat exchanger causes the first water flowing from the tank and third water flowing through the third flow path to exchange heat with each other to heat the third water flowing through the third flow path.   
     
     
         6 . The warm-water generating apparatus according to  claim 1 , further comprising:
 a tank;   a first circulation flow path that allows the first water to circulate between the tank and the second heat exchanger; and   a second flow path that is different from the first circulation flow path,   wherein a portion of the second flow path is disposed in the tank and allows the first water in the tank and second water flowing through the second flow path to exchange heat with each other to heat the second water flowing through the second flow path.   
     
     
         7 . The warm-water generating apparatus according to  claim 1 , further comprising:
 a tank that stores the first water; and   a flow path that has a portion disposed in the tank and through which second water flows,   wherein the second heat exchanger heats, in the tank, the first water stored in the tank, and   wherein the first water stored in the tank heats the second water flowing through the flow path.   
     
     
         8 . The warm-water generating apparatus according to  claim 1 , further comprising:
 a tank; and   a flow path through which the first water flows from a water supply source to the tank,   wherein the second heat exchanger heats the first water flowing through the flow path.   
     
     
         9 . The warm-water generating apparatus according to  claim 1 , further comprising:
 a use-side fourth heat exchanger that is different from the second heat exchanger; and   a fourth circulation flow path through which fourth water for cooling or heating flows,   wherein the fourth heat exchanger causes the refrigerant flowing therein and the fourth water flowing through the fourth circulation flow path to exchange heat with each other to cool or heat the fourth water.   
     
     
         10 . The warm-water generating apparatus 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).   
     
     
         11 . The warm-water generating apparatus according to  claim 10 ,
 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 −0.9473 x+ 57.497, −0.0016x 2 −0.0527 x+ 42.503), 
 the line segment A′B is represented by coordinates (x, 0.0029x 2 −1.0268 x+ 58.7, −0.0029x 2 +0.0268x+41.3), 
 the line segment DC′ is represented by coordinates (x, 0.0082x 2 −0.6671 x+ 80.4, −0.0082x 2 −0.3329 x+ 19.6), 
 the line segment C′C is represented by coordinates (x, 0.0067x 2 −0.6034 x+ 79.729, −0.0067x 2 −0.3966 x+ 20.271), and 
 the line segments BD, CO, and OA are straight lines. 
 
     
     
         12 . The warm-water generating apparatus according to  claim 10 ,
 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 −0.9473 x+ 57.497, −0.0016x 2 −0.0527 x+ 42.503), 
 the line segment A′B is represented by coordinates (x, 0.0029x 2 −1.0268 x+ 58.7, −0.0029x 2 +0.0268x+41.3), 
 the line segment DC′ is represented by coordinates (x, 0.0082x 2 −0.6671 x+ 80.4, −0.0082x 2 −0.3329 x+ 19.6), 
 the line segment C′C is represented by coordinates (x, 0.0067x 2 −0.6034 x+ 79.729, −0.0067x 2 −0.3966 x+ 20.271), and 
 the line segments GI, IA, BD, and CG are straight lines. 
 
     
     
         13 . The warm-water generating apparatus according to  claim 10 ,
 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 −13.112 x+ 380.43), 
 the line segment NK is represented by coordinates (x, 0.2421x 2 −29.955 x+ 931.91, −0.2421x 2 +28.955x−831.91), 
 the line segment KA′ is represented by coordinates (x, 0.0016x 2 −0.9473 x+ 57.497, −0.0016x 2 −0.0527 x+ 42.503), 
 the line segment A′B is represented by coordinates (x, 0.0029x 2 −1.0268 x+ 58.7, −0.0029x 2 +0.0268x+41.3), 
 the line segment DC′ is represented by coordinates (x, 0.0082x 2 −0.6671 x+ 80.4, −0.0082x 2 −0.3329 x+ 19.6), 
 the line segment C′C is represented by coordinates (x, 0.0067x 2 −0.6034 x+ 79.729, −0.0067x 2 −0.3966 x+ 20.271), and 
 the line segments JP, BD, and CG are straight lines. 
 
     
     
         14 . The warm-water generating apparatus according to  claim 10 ,
 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 −13.112 x+ 380.43) 
 the line segment MA′ is represented by coordinates (x, 0.0016x 2 −0.9473 x+ 57.497, −0.0016x 2 −0.0527 x+ 42.503), 
 the line segment A′B is represented by coordinates (x, 0.0029x 2 −1.0268 x+ 58.7, −0.0029x 2 +0.0268x+41.3), 
 the line segment DC′ is represented by coordinates (x, 0.0082x 2 −0.6671 x+ 80.4, −0.0082x 2 −0.3329 x+ 19.6), 
 the line segment C′C is represented by coordinates (x, 0.0067x 2 −0.6034 x+ 79.729, −0.0067x 2 −0.3966 x+ 20.271), and 
 the line segments JP, LM, BD, and CG are straight lines. 
 
     
     
         15 . The warm-water generating apparatus according to  claim 10 ,
 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 −13.112 x+ 380.43), 
 the line segment MA′ is represented by coordinates (x, 0.0016x 2 −0.9473 x+ 57.497, −0.0016x 2 −0.0527 x+ 42.503), 
 the line segment A′B is represented by coordinates (x, 0.0029x 2 −1.0268 x+ 58.7, −0.0029x 2 +0.0268x+41.3), 
 the line segment FT is represented by coordinates (x, 0.0078x 2 −0.7501 x+ 61.8, −0.0078x 2 −0.2499 x+ 38.2), 
 the line segment TP is represented by coordinates (x, 0.00672x 2 −0.7607 x+ 63.525, −0.00672x 2 −0.2393 x+ 36.475), and 
 the line segments LM and BF are straight lines. 
 
     
     
         16 . The warm-water generating apparatus according to  claim 10 ,
 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 −13.112 x+ 380.43), 
 the line segment RP is represented by coordinates (x, 0.00672x 2 −0.7607 x+ 63.525, −0.00672x 2 −0.2393 x+ 36.475), and 
 the line segments LQ and QR are straight lines. 
 
     
     
         17 . The warm-water generating apparatus according to  claim 10 ,
 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 −0.9473 x+ 57.497, −0.0016x 2 −0.0527 x+ 42.503), 
 the line segment A′B is represented by coordinates (x, 0.0029x 2 −1.0268 x+ 58.7, −0.0029x 2 +0.0268x+41.3), 
 the line segment FT is represented by coordinates (x, 0.0078x 2 −0.7501 x+ 61.8, −0.0078x 2 −0.2499 x+ 38.2), 
 the line segment TS is represented by coordinates (x, −0.0017x 2 −0.7869 x+ 70.888, −0.0017x 2 −0.2131 x+ 29.112), and 
 the line segments SM and BF are straight lines. 
 
     
     
         18 . The warm-water generating apparatus 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.   
     
     
         19 . The warm-water generating apparatus 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.   
     
     
         20 . The warm-water generating apparatus 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). 
     
     
         21 . The warm-water generating apparatus 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). 
     
     
         22 . The warm-water generating apparatus 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. 
 
     
     
         23 . The warm-water generating apparatus 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′, M′N, 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 −3.34 y+ 52.6, y, −0.132y 2 +2.34y+47.4); 
 the line segment M′N is represented by coordinates (0.0596y 2 −2.2541 y+ 48.98, y, −0.0596y 2 +1.2541y+51.02); 
 the line segment VG is represented by coordinates (0.0123y 2 −1.8033 y+ 39.6, y, −0.0123y 2 +0.8033y+60.4); and 
 the line segments NV and GM are straight lines. 
 
     
     
         24 . The warm-water generating apparatus 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 −0.6701 y+ 37.512, y, −0.0072y 2 −0.3299 y+ 62.488); 
 the line segment NU is represented by coordinates (0.0083y 2 −1.7403 y+ 56.635, y, −0.0083y 2 +0.7403y+43.365); and 
 the line segment UO is a straight line. 
 
     
     
         25 . The warm-water generating apparatus 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 −1.975 y+ 84.765, y, −0.0099y 2 +0.975y+15.235); 
 the line segment RT is represented by coordinates (0.0082y 2 −1.8683 y+ 83.126, y, −0.0082y 2 +0.8683y+16.874); 
 the line segment LK is represented by coordinates (0.0049y 2 −0.8842 y+ 61.488, y, −0.0049y 2 −0.1158 y+ 38.512); 
 the line segment KQ is represented by coordinates (0.0095y 2 −1.2222 y+ 67.676, y, −0.0095y 2 +0.2222y+32.324); and 
 the line segment TL is a straight line. 
 
     
     
         26 . The warm-water generating apparatus 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 −0.7103 y+ 40.1, y, −0.0064y 2 −0.2897 y+ 59.9); 
 the line segment ST is represented by coordinates (0.0082y 2 −1.8683 y+ 83.126, y, −0.0082y 2 +0.8683y+16.874); and 
 the line segment TP is a straight line. 
 
     
     
         27 . The warm-water generating apparatus 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 −5.234 z+ 88.94, z), 
 the line segment RG is represented by coordinates (−0.0491z 2 −1.1544 z+ 38.5, 0.0491z 2 +0.1544z+61.5, z), and 
 the line segments KB′ and GI are straight lines. 
 
     
     
         28 . The warm-water generating apparatus 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 −1.7429 z+ 72.0, −0.025z 2 +0.7429z+28.0, z), 
 the line segment RG is represented by coordinates (−0.0491z 2 −1.1544 z+ 38.5, 0.0491z 2 +0.1544z+61.5, z), and 
 the line segments JR and GI are straight lines. 
 
     
     
         29 . The warm-water generating apparatus 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 −0.984 z+ 47.1, −0.0083z 2 −0.016 z+ 52.9, z), 
 the line segment HR is represented by coordinates (−0.3123z 2 +4.234z+11.06, 0.3123z 2 −5.234 z+ 88.94, z), 
 the line segment RG is represented by coordinates (−0.0491z 2 −1.1544 z+ 38.5, 0.0491z 2 +0.1544z+61.5, z), and 
 the line segments PB′ and GM are straight lines. 
 
     
     
         30 . The warm-water generating apparatus 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 −0.984 z+ 47.1, −0.0083z 2 −0.016 z+ 52.9, z), 
 the line segment RG is represented by coordinates (−0.0491z 2 −1.1544 z+ 38.5, 0.0491z 2 +0.1544z+61.5, z), and 
 the line segments JR and GI are straight lines. 
 
     
     
         31 . The warm-water generating apparatus 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 −1.9622 z+ 59.069, z), 
 the line segment TP is represented by coordinates (0.0083z 2 −0.984 z+ 47.1, −0.0083z 2 −0.016 z+ 52.9, z), and 
 the line segment PS is a straight line. 
 
     
     
         32 . The warm-water generating apparatus 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 −211.71 z+ 3246.1, z), 
 the line segment UQ is represented by coordinates (0.0135z 2 −0.9181 z+ 44.133, −0.0135z 2 −0.0819 z+ 55.867, z), and 
 the line segments QB″ and B″D are straight lines.