How to distinguish the working principle between air conditioner and dehumidifier
Comparison of the working principle of air conditioners and dehumidifiers With the increasing living standards of people and the demand for high-quality living environment, most air conditioners are equipped with dehumidification functions. However, this is different from the working principle of dehumidifiers. The choice of the corresponding dehumidification method is the key to effectively adjust the environmental comfort.
In most cases, the human body is most comfortable in an air environment with a humidity of 55% to 65%. Above 70% humidity, the comfort of the human body will decrease. The air conditioner and the dehumidifier use the humidity to make the human body reach a certain level. Comfort, the way it works, has the same points and differences. Here's a quick overview of how they work.
Comparison of dehumidification principles
1. Air conditioner dehumidification principle
The air conditioner has a dehumidification function in two modes:
(I) Cooling mode This is the mode that any air conditioner has and the most basic function of the air conditioner. The process of air conditioner refrigeration is inevitably accompanied by dehumidification. After the humid air passes through the evaporator of the air conditioner, the temperature will drop drastically. The air humidity is in a supersaturated state, and the excess water vapor is precipitated in the form of condensed water and condenses on the fins of the evaporator. That is, "condensation", when the cooling mode reaches a certain equilibrium state, the air humidity will drop to a certain level.
(2) Independent dehumidification mode This method is called constant temperature dehumidification by the industry. Its basic principle is to reheat the air cooled by the evaporator to the original temperature and then into the room, so that the indoor environment is in the case of humidity drop. It remains relatively constant.
There are two ways to heat the air outlet temperature: one is to use electric heating components to heat the air passing through the evaporator. This kind of air conditioner is provided with electric heating device in the indoor unit. When the air is separated from the condensed water through the evaporator (low surface temperature), the heated air is heated by the electric heating device, so that the air outlet of the air conditioner and the air inlet are kept substantially the same. The other is to use the heat generated by the condenser to heat the dehumidified air (see Figure 2). This type of air conditioner has two exchangers a and b, which are respectively switched to evaporator and condenser in independent dehumidification mode. Similarly, air is separated from evaporator a (surface low temperature) to precipitate condensed water, and then replaced by condenser b (surface high temperature). In the first mode, the function of the electric heating component also keeps the air outlet of the air conditioner and the temperature of the air inlet substantially the same. These two heating methods are only different heating devices and heating methods, the latter is purely physical.
2. Desiccator works
The working principle of the dehumidifier is simply to use the moisture in the air to condense and frost when entering the dehumidifier evaporator, and then accumulate and drip out, and discharge into the water outlet, thereby achieving the purpose of reducing the humidity of the space. The principle is similar to the dehumidification principle in the air conditioner cooling mode.
The difference between the operation mode of air conditioner and dehumidifier
Compared with the independent dehumidification mode, the cooling mode, as the basic function of the air conditioner, has lower requirements on the structural design and control mode of the air conditioner, and the cost is low. However, in this way, the purpose of dehumidification is inevitable, which will inevitably cause the room temperature to drop. This is not practical and wastes power when the temperature is not high. In fact, the dehumidification function in the cooling mode is only a by-product, and does not increase the cost of the air conditioner.
Independent dehumidification mode uses electric heating or heat exchange to heat the air outlet. The control will be more complicated and the design cost is higher. However, this temperature compensation will make the room temperature fluctuation relatively small, suitable for the temperature is not high, but the humidity is too high. Used when. The air conditioner operates in these two independent dehumidification modes, and its refrigeration system is in an efficient operation state, and the operating conditions of the evaporator and the condenser are relatively reasonable, and the energy efficiency ratio 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 rise slightly, but the temperature difference is not obvious. It is more suitable for the wet season outside the summer, and the electricity consumption is relatively low.
However, for the dehumidifier, when the ambient temperature is lower than 15 °C, the water droplets attached to the surface of the evaporator will freeze and the dehumidification effect will be weakened. If the ambient temperature exceeds 40 °C, the pressure in the system will increase and the compressor will be overloaded. At this time, the overload protector should cut off the line, otherwise the compressor motor will be damaged. Therefore, the optimum operating temperature range of the dehumidifier is 15 °C ~ 40 °C.
Many users will ask: "Can the air conditioner not dehumidify? With the air conditioner, does the dehumidifier become redundant?" In fact, this is a misunderstanding of consumption. The main function of the air conditioner is cooling and heating, with independence. The dehumidification air conditioner can dehumidify, but the dehumidification amount is small and the dehumidification is slow; and in the rainy season in the south, the temperature is not high. If the air conditioner is used to dehumidify, the cold air is blown out, and the dehumidification will be colder, giving the person a colder The feeling will be quite uncomfortable. In addition, since the air conditioner is in a fixed position, it can only be dehumidified in a small area, and the long-term dehumidification operation of the air conditioner will increase the load of the compressor, which not only consumes a large amount of electricity, but also easily damages the compressor and shortens the whole. The life of the machine. Therefore, the air conditioner is not suitable for use in place of the dehumidifier.