What is the difference between air source heat pump and air conditioning?
Difference in working principle
Air source heat pump: electric drive compressor works to compress low temperature refrigerant into high temperature refrigerant. The high temperature refrigerant exchanges heat with water through hot water heat exchanger. The high temperature refrigerant after heat exchange is depressurized by expansion valve and absorbed by air through evaporator. The heat, the heat-absorbing refrigerant is sucked by the compressor, continuously absorbs heat from the air, releases heat on the hot water heat exchanger side, and heats the cold water. The heat absorbed by the water is the sum of the heat generated by the compression of the compressor and the heat absorbed by the refrigerant.
Air conditioner: The electric drive compressor works to compress the low temperature refrigerant into a high temperature refrigerant. The high temperature refrigerant is cooled by the evaporator. The air conditioner main unit fan discharges the heat to the outside. The high temperature refrigerant after the heat dissipation is depressurized by the expansion valve and then absorbed by the air conditioner indoor unit evaporator. The heat in the air reduces the indoor temperature, and the refrigerant after the heat absorption is sucked by the compressor. In this way, the heat is continuously discharged from the room to the outdoor air, and the heat is absorbed from the room to reduce the indoor temperature.
Difference in heating method
Air source heat pump: The air energy heat pump itself is just a device that provides hot water. It supplies heat and then uses other heating ends to achieve heating. For example, radiators, fan coils, air-heating machines, floor heating pipes, etc. can be used as heating ends, and different heating modes can be selected according to different houses.
Air conditioning: Whether it is a vertical cabinet air conditioner or a wall-mounted air conditioner, it can only use the active hot air to achieve heating.
Air source heat pump: heat pump special compressor, antifreeze high efficiency tank condenser, outdoor fin heat exchanger with hydrophilic membrane, and system high pressure protection control.
Air conditioning: air conditioning compressor, fin condenser or plate condenser, outdoor fin heat exchanger without hydrophilic membrane
Among these components, the difference between the compressors is the biggest difference between the air source heat pump and the air conditioner, because different compressors determine the use effect and the use area of the product. The air conditioner uses an air conditioner compressor. Take R22 as an example. The maximum operating pressure does not exceed 2 MPa, the compressor ratio is less than 7, and the maximum exhaust temperature does not exceed 90 °C. However, the air source heat pump must use a heat pump compressor, also taking R22 as an example. The operating pressure reaches 3 MPa, the compressor ratio reaches 12, and even higher to 20, and the maximum exhaust temperature reaches 110 °C. The difference of these parameters requires that the processing precision of the heat pump compressor, the bearing strength, and the temperature resistance of the motor have an order of magnitude improvement compared with the air conditioner compressor.
What is the difference between air source heat pump and air conditioning?
Heat transfer mechanism difference
Air source heat pump: Although the heat transfer is realized by the refrigerant, in the final heat exchange stage, the heat pump uses water to exchange heat, and the air conditioner uses the refrigerant as the medium from beginning to end. One is the water cycle and the other is the fluorine cycle. In the water cycle, even if the heat pump is stopped, the water will always stay in the indoor pipe and continuously emit temperature. This is equivalent to a buffering process that adds a heat. Moreover, if a fan coil or an air-heating machine is used as the end, the hot air is obtained from the hot water at the end, so the overall humidity is more in line with the physiological habits of the human body, and does not cause "air conditioning disease" such as dry mouth and dry mouth.
Air conditioning: The air conditioner uses a "fluorine cycle" to achieve heat transfer. The air conditioning vents discharge a lot of hot air, and the purpose of warming is indeed achieved, but this violent active heat convection scheme will greatly increase the amount of water evaporation on the surface of the human skin, resulting in dry air, dry mouth and poor comfort.
Difference in operation mode
There are the following differences between air source heat pumps and air conditioners:
First: Although the air source heat pump is energized all day, when the heating is completed, the unit will stop working and automatically keep warm. The working hours of the household machines generally do not exceed 2 hours per day, so the air source heat pump is more energy efficient than the air conditioner, and can better protect the compressor and prolong its service life.
Second: air conditioners are used frequently in summer, especially in the north, but air source heat pumps integrate hot water, heating, and cooling, and operate in winter for a long time. Especially in winter, the demand for hot water is large, so the air source heat pump needs longer operation to raise the water temperature, and the compressor needs more time to run, so the compressor basically runs in the area with higher refrigerant. . Operating temperature is one of the main factors affecting the life of the compressor. Under the same time of operation, the combined load of the compressor in the air source heat pump is higher than that of the compressor in the air conditioner.
Use environment difference
Air conditioning and air source heat pumps can be used at different ambient temperatures. When the air conditioner is heating, the ambient temperature is up to 21 °C. According to the national standard, the best use environment is 21 °C to -7 °C. However, the air source heat pump is different. For the hot water machine, it should be used in the spring and autumn. According to the national standard of the air source heat pump, its use range is 43 ° C to -20 ° C. Since the air source heat pump has a wider ambient temperature range, it uses a higher specification of components than the air conditioner.
In addition, air source heat pumps require higher temperatures and pressures due to different environments and purposes. The maximum air outlet temperature of the air conditioner is also 50 ° C, and the condensation pressure is 1.8 to 2 MPa at this time. The air source heat pump requires 60 ° C or even 65 ° C, and the condensing pressure at this time reaches 2.5 to 2.8 MPa. The pressure difference of 340%, plus the low temperature environment, especially -20 °C, the evaporation pressure is also very low, 0.2 ~ 0.15MPa, the water temperature is still heated to over 50 ° C, or 60 ° C or even 65 ° C, At this time, the condensing pressure is still 2.7 ~ 2.8MPa, the compression ratio is much greater than 15, which is greater than the compression ratio of the air conditioner compressor.
System defrosting difference
In general, the greater the difference between the temperature of the refrigerant and the outdoor temperature, the more severe the frosting. The air source heat pump itself relies on small temperature difference heat transfer, and the air conditioner is a large temperature difference. The air source heat pump focuses on heating in winter, and it absorbs heat in a low temperature environment. The temperature in winter is minus ten or twenty degrees, while the temperature of the refrigerant is minus twenty or thirty degrees, and the temperature difference is only ten degrees. The air conditioner focuses on cooling. In summer, the maximum temperature is also 45 ° C, and the compressor discharge temperature reaches 890 degrees, even 100 ° C, the temperature difference is forty or fifty degrees.
Therefore, under the same circumstances, the heat exchange area of the air source heat pump is much larger than the heat exchange area of the air conditioner, which is why the air source heat pump is larger than the air conditioner.
According to the conventional control logic, the defrosting time of the air conditioner is generally about 10 minutes, and the defrosting time of the air source heat pump heating unit is usually a local control logic, such as Qingdao, Shandong and Qinhuangdao in Hebei, the defrosting is more than the Shanxi area. Frequently. Professional air source heat pump manufacturers are generally a latitude control logic and adjusted according to local climate conditions.
The advanced stage of defrosting is "there is frost defrosting, no frost, no frost, no frost, less frost, less defrosting". This is under the premise of perfect pressure and temperature control system. At present, there are only some high-end machines. The type is only available because of the high cost. Whether it is from the control logic and the area of the evaporator, or from the difference between the refrigerant and the outdoor temperature, the defrosting performance of the air source heat pump is much better than that of the air conditioner, and the possibility of frost formation is smaller, so the overall supply is provided. The effective heat is greater than the air conditioner.