Gree GRS-1.5/D150ANbA-K, Service Manual

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GREE AIR SOURCE HEAT PUMP WATER HEATER SERVICE MANUAL
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5 Working Principle
5.1 Brief Introduction to Working Principle
As the refrigerant has different phase-transition temperature under varied pressure, it enables the
heat pump to transfer heat of low-temperature heat source to the high-temperature heat source. The air
source water heater unit utilizes the heat pump to obtain heat from the ambient low-grade energy (air
source) via thermodynamic cycle by consuming partial electrical energy, and then delivers heat to the
water tank for heating up water.
5.2 Working Diagram
The compressor consumes partial electrical energy to compress the refrigerant into
high-temperature and high-pressure gas. After entering the condenser (the water tank coil of a water
heater in static heat up mode), the gaseous refrigerant transfers its heat to water as its saturation
temperature is higher than the water temperature and leaves the condenser after condensing into liquid.
The liquid refrigerant enters the throttling device (generally the electronic expansion valve) for speedup
and pressure reduction. As partial liquid vaporizes, the liquid refrigerant has two states (gas and liquid)
when leaving the throttling device. The low-pressure refrigerant enters the vaporizer (the finned tube
exchanger of a water heater in static heat up mode) and is vaporized into liquid after absorbing heat from
air as its saturation temperature is lower than the air temperature. The low-pressure gas is inhaled by the
compressor for the next cycle.