Defrost cycle performance for an air-source heat pump with a scroll and a reciprocating compressor

摘要: A 10.6 kW nominal cooling capacity air-source heat pump was tested according to ANSI/ASHRAE Standard 116-1983 for the frost acumulation and defrost cycle. These tests required indoor conditions of 21.1°C (70°F) dry-bulb, 15°C (60°F) maximum wet-bulb, with outdoor 1.7°C (35°F) 0.5°C (30°F) wet-bulb. The unit original scroll compressor a reciprocating that yielded similar heating performance. Heating system peaked at 8.4 (2.38 tons), while 8.5 (2.42 tons) during frosting period. capacities two configurations differed by less than 1% Power demand 2.9 kW, power 3.1 kW. During period, averaged 7% higher demand. completed 5% faster system. Scroll time 6.8 min 6.5 min. volume condensate produced 3% 1680 ml (102.5 in3) 1640 (100 systems, respectively. Discharge pressures were within peak values 1315 kPa (191 psia) 1351 (196 systems levels discharge superheat, peaking 53°C (95°F) compared superheat 47°C (85°F). Overall, 18% refrigerant flowrates Refrigerant 3.7 kg min−1 (8.2 lbm min−1) 4.0 (8.8