Comparison of the working principles of air conditioners and dehumidifiers With the improvement of people's living standards and the demand for high-quality living environments, most air conditioners have dehumidification functions. However, this is different from the working principle of dehumidifiers. Choosing the appropriate dehumidification method is the key to effectively regulating environmental comfort.
In most cases, the human body is most comfortable in an air environment with a humidity of 55% to 65%. When the humidity exceeds 70%, the comfort of the human body will decrease. Air conditioning and dehumidifiers use humidity to reach a certain level in the human body. Comfort is the way it works, with the same key points and differences. The following is a quick overview of their working principles.
Comparison of dehumidification principles
1. Principle of air conditioning dehumidification
The air conditioner has two modes of dehumidification function:
(I) Cooling mode is the most basic function of any air conditioning system. The refrigeration process of air conditioning is inevitably accompanied by dehumidification. After the humid air passes through the evaporator of the air conditioner, the temperature will sharply decrease. The air humidity is in a supersaturated state, and excess water vapor precipitates in the form of condensed water and condenses on the heat sink of the evaporator. That is to say, "condensation" means that when the cooling mode reaches a certain equilibrium state, the air humidity will decrease to a certain level.
(2) The independent dehumidification mode is called constant temperature dehumidification in industry. The basic principle is to reheat the air cooled by the evaporator to its original temperature and then enter the indoor environment in case of a decrease in humidity. It remains relatively constant.
There are two methods to heat the air outlet temperature: one is to use an electric heating component to heat the air passing through the evaporator. This type of air conditioner is equipped with an electric heating device on the indoor unit. When the air is separated from the condensed water through the evaporator (low surface temperature), the heated air is heated by an electric heating device, thereby maintaining the air outlet and inlet of the air conditioner basically the same. Another method is to use the heat generated by the condenser to heat the dehumidified air (see Figure 2). This type of air conditioning has two exchangers a and b, each switching to an evaporator and a condenser in an independent dehumidification mode. Similarly, separate the air from evaporator a (low surface temperature) to precipitate the condensate, and then replace it with condenser b (high surface temperature). In the first mode, the function of the electric heating element also keeps the temperature of the air outlet and air inlet of the air conditioner basically the same. These two heating methods are only different from the heating device and heating method, which are purely physical.
2. Dryer engineering
The working principle of a dehumidifier is: when entering the evaporator of the dehumidifier, it uses the moisture in the air to condense and form frost, then accumulates and drips, and is discharged into the water outlet, thereby achieving the goal of reducing space humidity. This principle is similar to the dehumidification principle in air conditioning refrigeration mode.
Differences in the operating modes of air conditioning and dehumidifiers
Compared with the independent dehumidification mode, the refrigeration mode, as the basic function of air conditioning, has lower requirements for the structural design and control mode of the air conditioning and lower costs. However, in this way, the purpose of dehumidification is inevitable, which will inevitably lead to a decrease in room temperature. This is unrealistic and wastes power when the temperature is not high. In fact, the dehumidification function in refrigeration mode is only a by-product and will not increase the cost of air conditioning.
The independent dehumidification mode uses electric heating or heat exchange to heat the air outlet. Control will be more complex and design costs will be higher. However, this temperature compensation will cause relatively small temperature fluctuations in the room, making it suitable for situations where the temperature is not high but the humidity is too high. When to use. The air conditioner operates in these two independent dehumidification modes, and its refrigeration system is in efficient operation. The operating conditions of the evaporator and condenser are relatively reasonable, and the energy utilization rate is high.
The dehumidifier works by cooling the inside of the machine and analyzing the water in the air. The temperature of the space will slightly increase, but the temperature difference is not significant. More suitable for rainy seasons outside of summer, with relatively low electricity consumption.
However, for dehumidifiers, when the ambient temperature is below 15 ℃, the water droplets attached to the evaporator surface will freeze and the dehumidification effect will weaken. If the ambient temperature exceeds 40 ° C, the pressure in the system will increase and the compressor will be overloaded. At this point, the overload protector should cut off the circuit, otherwise it may damage the compressor motor. Therefore, the optimal operating temperature range for dehumidifiers is between 15 ° C and 40 ° C.
Many users may ask, "Can air conditioning not dehumidify? With air conditioning, do dehumidification opportunities become redundant?" In fact, this is a misconception about consumption. The main function of air conditioning is refrigeration and heating, operating independently. Dehumidifying air conditioning can dehumidify, but the dehumidification amount is small and the dehumidification is slow. The rainy season in the south has low temperatures. If air conditioning is used for dehumidification, blowing out cold air will make dehumidification colder and give people a colder feeling. In addition, due to the fixed position of the air conditioner, dehumidification can only be carried out in small areas. Long term dehumidification operation of the air conditioner will increase the load on the compressor, not only consuming a large amount of air. Electricity, but it is also easy to damage the compressor and shorten the overall lifespan. The lifespan of the machine. Therefore, this air conditioner is not suitable for replacing dehumidifiers.