Air source heat pump (ASHP) is a device that uses low-grade heat energy in ambient air and upgrades it to high-grade heat energy through heat pump technology. It is widely used in industrial system hot water supply, and its working principle is based on the reverse Carnot cycle of thermodynamics. The following is the working principle of air source heat pump to provide industrial system hot water.
Basic Principle
The air source heat pump absorbs heat from the air and transfers it to the water through the phase change cycle of the refrigerant (evaporation, compression, condensation, expansion), thereby heating the water. Its core is to use electrical energy to drive the compressor to transfer heat from the low-temperature heat source (air) to the high-temperature heat source (water).
Main components
Evaporator: Absorbs heat from the air and evaporates the low-temperature, low-pressure liquid refrigerant into a low-temperature, low-pressure gaseous refrigerant.
Compressor: Compresses the low-temperature, low-pressure gaseous refrigerant into a high-temperature, high-pressure gaseous refrigerant to increase its energy level.
Condenser: The high-temperature, high-pressure gaseous refrigerant releases heat in the condenser to heat the cold water, while the refrigerant condenses into a high-pressure liquid.
Expansion valve: The high-pressure liquid refrigerant is depressurized by the expansion valve and becomes a low-temperature, low-pressure liquid refrigerant, which re-enters the evaporator to complete the cycle.
Working process
(1) Evaporation heat absorption
In the evaporator, the low-temperature, low-pressure liquid refrigerant absorbs heat from the air and evaporates into a low-temperature, low-pressure gaseous refrigerant.
The air temperature drops and the heat is transferred to the refrigerant.
(2) Compression temperature increase
The low-temperature, low-pressure gaseous refrigerant is compressed by the compressor and becomes a high-temperature, high-pressure gaseous refrigerant.
The compression process consumes electrical energy, and the temperature and pressure of the refrigerant increase significantly.
(3) Condensation heat release
The high-temperature, high-pressure gaseous refrigerant enters the condenser and exchanges heat with the cold water.
The refrigerant releases heat and condenses into a high-pressure liquid, while the cold water is heated.
(4) Expansion pressure reduction
The high-pressure liquid refrigerant passes through the expansion valve, and the pressure drops suddenly, becoming a low-temperature, low-pressure liquid refrigerant.
The refrigerant re-enters the evaporator and starts the next cycle.
Energy efficiency ratio (COP)
The energy efficiency ratio (Coefficient of Performance, COP) of an air source heat pump refers to the ratio of its heating capacity to the input electrical energy. The higher the COP value, the higher the efficiency of the heat pump. Usually, the COP of an air source heat pump is between 3 and 5, which means that 1 unit of electrical energy can generate 3 to 5 units of heat energy.
Application scenarios
- Food processing industry (cleaning, sterilization, etc.).
- Chemical industry (reactor heating, process water heating).
- Textile industry (dyeing, washing, etc.).
- Electroplating industry (tank heating).
- Hospitals, etc. Domestic hot water supply.