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How heat pumps work

2021-11-04


It is a natural law that water flows from high to low places, and heat is transferred from high-temperature objects to low-temperature objects. However, in real life, in order to meet the needs of agricultural irrigation and domestic water, people use water pumps to transport water from low-lying places to high places. Similarly, in today's energy shortage, heat pumps are used to transfer heat energy from low-temperature objects to high-temperature objects, and then heat water or heat by high-temperature objects to make full use of heat. The principle of operation of the heat pump system is the same as that of the refrigeration system. To understand heat pumps, you first need to understand how a refrigeration system works. The refrigeration system (compression refrigeration) is generally composed of four parts: compressor, condenser, throttle valve and evaporator. The working process is as follows: low-temperature and low-pressure liquid refrigerants (such as Freon) first absorb heat from a high-temperature heat source (such as room temperature air) in an evaporator (such as an air-conditioning indoor unit) and vaporize into low-pressure steam. Then the refrigerant gas is compressed into high-temperature and high-pressure steam in the compressor, and the high-temperature and high-pressure gas is cooled and condensed into a high-pressure liquid by a low-temperature heat source (such as cooling water) in the condenser. Throttling elements (capillaries, thermostatic expansion valves, electronic expansion valves, etc.) throttling. ) to obtain low-temperature and low-pressure liquid refrigerants. This is how the refrigeration cycle is completed. The performance of heat pumps is generally evaluated by the coefficient of refrigeration (COP coefficient of performance). The refrigeration coefficient is defined as the ratio of the amount of heat transferred from a low-temperature object to the required power. Generally speaking, the cooling coefficient of the heat pump is about 3-4, which means that the heat pump can transfer 3-4 times the heat energy required by itself from the low-temperature object to the high-temperature object. Therefore, a heat pump is essentially a heat lifting device. Very little electrical energy is consumed during operation, but 4-7 times more electricity can be extracted from environmental media (water, air, soil, etc.). ), and heat up utilization, which is also the reason why heat pumps save energy. Europe, the United States and Japan are competing to develop a new type of heat pump. It is reported that the cooling coefficient of the new heat pump can reach 6 to 8. If this value can be popularized, it means that energy will be used more efficiently. The popularity of heat pumps will also increase significantly. A ground source heat pump is a type of heat pump that uses earth or water as a source of cold and heat to heat buildings in winter. Air conditioning technology to cool buildings in summer. Ground-source heat pumps only "transfer" energy between the earth and the room. Very little electricity is used to maintain the required indoor temperature. In winter, 1 kilowatt of electricity sends 4-5 kilowatts of heat from soil or water into the room. In summer, on the contrary, indoor heat is transferred to soil or water through heat pumps, so that the indoor air is cool. The energy obtained underground will be used in winter. In this way, the architectural space is integrated with nature. Get a comfortable living environment at a low cost

 

 

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