A novel testing and theoretical approach for air-source heat-pump water heater with flash tank vapor-injection

Abstract Air-source heat-pump (ASHP) water heater provides an important low-carbon solution for domestic heating, which regains interest in the context of pursuing global carbon neutrality. In this study, a novel testing and theoretical approach is proposed ASHP with flash tank vapor-injection by retrofitting methods state points. Five vapor-injections different temperature levels are tested verified method heater. On basis compressor suction temperature, exhaust electronic expansion valve pre-throttle throttling thermodynamic analysis conducted to determine system performances. The relationship between pressure ratio, heating capacity COP identified adjusting opening degree system. results show that firstly decreases subsequently increases increase minimum appears when ratio 0.3. This study new insights into advanced