Differences Between Heat Pump and Air Conditioner

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Date:2022/03/08

Principle difference

The electric drive compressor works, compresses the low-temperature refrigerant into a high-temperature refrigerant, and the high-temperature refrigerant exchanges heat with water through the hot water heat exchanger. The hot refrigerant is inhaled by the compressor, continuously absorbs heat from the air, releases heat on the side of the hot water heat exchanger, and heats the cold water. The heat absorbed by the water is the sum of the heat generated by the compressor and the heat absorbed by the refrigerant. Air conditioner: The electric drive compressor works, compresses the low-temperature refrigerant into a high-temperature refrigerant, the high-temperature refrigerant is dissipated by the evaporator, the air-conditioning host fan discharges the heat to the outside, and the heat-dissipated high-temperature refrigerant is depressurized by the expansion valve and absorbed by the evaporator of the indoor unit of the air conditioner. The heat in the air reduces the indoor temperature, and the refrigerant after absorbing heat is sucked by the compressor. In this way, the heat is continuously discharged from the indoor to the outdoor air, and the heat is absorbed from the indoor to achieve the purpose of lowering the indoor temperature.

Differences in heating method

The air source heat pump itself is just a device that provides hot water. It provides heating, and then cooperates with other heating terminals to achieve heating, such as radiators, fan coil units, air energy floor heating, floor heating pipes, etc., can be used as its heating terminals, and different heating methods can be selected according to different houses. Air conditioning: Whether it is a vertical cabinet air conditioner or a wall-mounted air conditioner, heating can only be achieved by using active hot air.

Component Differences

Special compressor for heat pump, antifreeze high-efficiency tank condenser, outdoor fin heat exchanger with hydrophilic membrane, and system high pressure protection control. Air conditioner: air conditioner compressor, fin condenser or plate condenser, outdoor fin heat exchanger without hydrophilic membrane, no protection control such as system high pressure. Among these parts, the difference between compressors is the biggest difference between air source heat pumps and air conditioners, because different compressors determine the use effect of the product and the area of use. The air-conditioning uses an air-conditioning compressor. Taking R22 as an example, the maximum operating pressure does not exceed 2MPa, 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. The operating pressure reaches 3MPa, the compressor ratio reaches 12, or even higher to 20, and the maximum exhaust temperature reaches 110℃. The difference in these parameters requires that the processing accuracy, bearing strength, and motor temperature resistance of heat pump compressors be improved by orders of magnitude compared to air-conditioning compressors.

Differences in heat transfer mechanism

Although the transfer of heat is achieved through refrigerant, in the final heat exchange stage, the heat pump uses water to exchange heat, and the air conditioner uses refrigerant as a 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 shut down, the water flow will always stay in the indoor pipes and continuously dissipate the temperature. This is equivalent to adding a heat buffer process. Moreover, if a fan coil unit or an air-energy floor heater 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 will not cause "air conditioning diseases such as dry mouth." Air conditioning: air conditioning Adopt "fluorine cycle" to realize heat conduction. The air outlet of the air conditioner discharges a large amount of hot air, and the purpose of heating 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, hoarse throat, and dry mouth. Moreover, the air conditioner basically blows out the air from above. If it is too close to the human body, the experience of hot air blowing directly on the head is not good, and the comfort is poor.

Differences in how it works

First, whether it is cooling or heating, the working time of the air conditioner is longer, the space for cooling or heating is larger, and the cold/hot air produced is easy to lose, so the power of the air conditioner is generally relatively high. Although the air source heat pump is powered on all day, when the heating is completed, the unit will stop working and automatically keep warm. This process does not require power consumption, and the thermal insulation effect of the high-quality water tank can reach more than 72 hours. Generally, the working time of household machines does not exceed 2 hours per day, so the air source heat pump saves electricity than the air conditioner, and can better protect the compressor and prolong its service life.
Second, air conditioners are frequently used in summer, especially in northern regions, but air source heat pumps integrate hot water, heating, and cooling, and operate for a long time in winter. Especially in winter, the demand for hot water is large, so the air source heat pump needs to run for a longer time to increase the water temperature, and the compressor needs more time to run, so the compressor basically runs in the area with high refrigerant. . Operating temperature is one of the main factors affecting the life of the compressor. Under the condition of running for the same time, the comprehensive load of the compressor in the air source heat pump is higher than that of the compressor in the air conditioner.
Third, with the vigorous implementation of the "coal-to-electricity" project, people have gradually discovered many advantages of the air source heat pump, such as safety and convenience, energy saving and high efficiency, environmental protection and beauty, which is also an important reason why more and more people choose it. If the air source heat pump is used for hot water supply + heating + cooling, the operating time will be much longer than that of the air conditioner.

Use environment differences

When the air conditioner is heating, the maximum ambient temperature is 21°C, and the national standard stipulates that the best use environment is 21°C to -7°C. But the air source heat pump is different. For the water heater, it is also used in spring and autumn. According to the national standard requirements of the air source heat pump, its use range is 43 ℃ to -20 ℃. Because the air source heat pump has a wider ambient temperature range, the specifications and selection of components it uses are more demanding than those of air conditioners. In addition, due to different use environments and purposes, air source heat pumps have higher requirements in terms of temperature and pressure. The maximum outlet air temperature of the air conditioner is 50°C, and the condensing pressure at this time is 1.8-2MPa. The air source heat pump requires 60°C or even 65°C, and the condensing pressure at this time reaches 2.5-2.8MPa. The pressure difference of 30 to 40%, coupled with the low temperature environment, especially -20 ℃, the evaporation pressure is also very low, 0.2 ~ 0.15MPa, the water temperature still needs to be heated to more than 50 ℃, or 60 ℃ or even 65 ℃, At this time, the condensing pressure is still 2.7-2.8MPa, and the compression ratio is much larger than 15, which is larger than the range of the air-conditioning compressor.

Installation cost variance

The advantage of the air energy heat pump is that the heating and cooling are more comfortable, and at the same time, it saves electricity. The disadvantage is that the initial installation cost is relatively high. Traditional air conditioners are cheap and easy to install, and they are also the choice of many home users. However, if it is a long-term consideration, the actual cost of the air-source heat pump is indeed the lowest. The reason is very simple. The life of the air-source heat pump can reach more than 30 years, while the traditional household air conditioner is generally between 7-10 years. After calculating the monthly electricity bill, the average power consumption of the air source heat pump is less than 2/5 of that of the traditional air conditioner. After one year, the air source heat pump can greatly save unnecessary expenses.

Installation method difference

Air energy heat pump is a kind of concealed heating equipment. Through floor heating pipes and ceiling air panels, both heating and cooling are installed in very concealed places, which are both beautiful and space-saving. The home air conditioner needs to occupy the space on the wall or the ground, which affects the overall design planning and effect.

Differences in Design Difficulty

The two have different focuses at the beginning of the design. Ordinary heating and cooling air conditioners only allow the air conditioner to have the function of heating. Whether the heat is enough and whether the stability is good is not the design focus. On the basis that the cooling advantages are not lost to ordinary air conditioners, the heating capacity without electricity auxiliary is also super strong, especially in the low temperature environment, the heating pipes are sufficient and the pipes are stable, which requires very high circulation.