Dehumidification principle and working principle o

2022-07-31
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Analysis on dehumidification principle and working principle of dehumidifier for air conditioner

comparison of dehumidification principles

1 Air conditioner dehumidification principle

the air conditioner has dehumidification function in two modes:

a) refrigeration mode this is the mode that any air conditioner has, and it is also the most basic function of the air conditioner. The refrigeration process of the air conditioner must be accompanied by dehumidification. The temperature of the humid air will drop significantly after it passes through the evaporator of the air conditioner. The air humidity is in a supersaturated state, and the excess water vapor will be separated out in the form of condensate and condensed on the fins of the evaporator, that is, "condensation". When the refrigeration mode reaches a certain equilibrium state, the air humidity will drop to a certain level

b) independent dehumidification mode is called constant temperature dehumidification by industry insiders. Its basic principle is to reheat the air cooled by the evaporator to the original temperature, and then send it indoors, so that the indoor environment remains relatively constant when the humidity drops

there is also an oversupply of supply at the heating air outlet. There are also two methods for temperature control: one is to use electric heating components to heat the air passing through the evaporator (see Figure 1). The indoor unit of this kind of air conditioner is equipped with an electric heating device. When the air passes through the evaporator (low temperature on the surface) to precipitate condensate, the electric heating device will heat this part of cooled air, so that the temperature at the air outlet and air inlet of the air conditioner is basically the same; The other is to use the heat generated by the condenser to heat the dehumidified air (see Figure 2). This kind of air conditioner is equipped with two exchangers A and B, which are switched to evaporator and condenser respectively in the independent dehumidification mode. The same air separates condensate through evaporator a (low surface temperature), and then condenser B (high surface temperature) replaces the role of electric heating components in mode I, which also keeps the temperature of air conditioner outlet and air inlet basically the same. These two heating methods are only different from heating devices and heating methods, and the latter is purely physical

2. Working principle of the dehumidifier

the working principle of the dehumidifier is simply to use the moisture in the air to condense and frost when entering the evaporator of the dehumidifier, then accumulate and drip out, and discharge it into the water outlet, so as to achieve the advantage of Jinan assay spring torsion testing machine to reduce the space humidity. Its principle is similar to that of dehumidification in the refrigeration mode of air conditioner

difference between the working mode of air conditioner and dehumidifier

compared with the independent dehumidification mode, if the refrigeration mode is the basic function of air conditioner, the requirements for the structural design and control mode of air conditioner are relatively low, and the cost is low. However, when this mode is used to achieve the purpose of dehumidification, the room temperature will inevitably drop, which is not practical and wastes power when the temperature is not high. In fact, the dehumidification function in the refrigeration mode is only a by-product and does not increase the cost of the air conditioner

the independent dehumidification mode uses electric heating or heat exchange to heat the air at the air outlet. The control will be more complex and the design cost is relatively high. However, this temperature compensation will make the room temperature fluctuation relatively small, which is suitable for use when the temperature is not high but the humidity is too high. When the air conditioner operates in these two independent dehumidification modes, its refrigeration system is in a high-efficiency operation state, and the operating conditions of the evaporator and condenser are more reasonable, with high energy efficiency ratio

the working mode of the dehumidifier is to reduce the temperature inside the machine and analyze the water in the air. On the contrary, the temperature of the space will rise slightly, but the temperature difference is not obvious. It is more suitable for wet seasons outside midsummer, and the power consumption is relatively saved

however, for the dehumidifier, when the ambient temperature is lower than 15 ℃, the water droplets attached to the evaporator surface will freeze and weaken the dehumidification effect. If the ambient temperature is higher than 40 ℃, the pressure in the system will increase and overload the compressor. 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 ℃ ~ 40 ℃

many users will ask, "can't air conditioners also dehumidify? With air conditioners, don't dehumidifiers become redundant?" In fact, this is a consumption misunderstanding. The main functions of air conditioners are cooling and heating. Air conditioners with independent dehumidification function can dehumidify, but the dehumidification capacity is small and the dehumidification is slow; Moreover, in the rainy season in the south, the temperature is not high. At this time, if the air conditioner is used for dehumidification, the cold wind will be blown out. The more dehumidified, the colder it will be, which will make people feel very uncomfortable

in addition, since the air conditioner is in a fixed position, it can only be dehumidified in a local small area. At the same time, the long-term dehumidification operation of the air conditioner will also increase the load of the compressor, which not only consumes large power, but also easily damages the compressor and shortens the service life of the whole machine. Therefore, the air conditioner is not suitable to replace the dehumidifier

how to correctly select dehumidification mode

1 According to the use occasion

for the living environment, it should be more economical to select air conditioners for dehumidification. Since the air humidity most suitable for people is 60~70%, this humidity is relatively easy to achieve for air conditioners. The noise of dehumidifier is greater than that of air conditioner, especially the high-power dehumidifier, so air conditioner dehumidification is the first choice in residential occasions

2. According to the object of use

for industrial products that need to strictly control humidity, such as optical lenses, magnetic recording materials (including optical discs), image films, electronic information media, electronic raw devices, instruments, meters, powder materials, paper, wood, silk, leather, tobacco, food, tea, grain and other items, the use of special dehumidifiers has obvious effect. It is recommended to use dehumidifiers for dehumidification. Only 8.4%

3 According to the climatic conditions of the use area, the common climates are no more than the following: (1) high temperature and high humidity - muggy weather in summer; (2) High temperature and low humidity - dry and hot season in northern climate; (3) Low temperature and high humidity - rainy season in the South; (4) Low temperature and humidity - usually refers to the cold weather in the north. The climate that usually needs dehumidification is mainly (1) and (3). For high temperature and high humidity areas, it is recommended to use air conditioners to reduce the temperature during dehumidification through refrigeration mode; For low temperature and high humidity areas, it is recommended to use air conditioners or dehumidifiers with independent dehumidification mode

to sum up, there are still differences between dehumidification of air conditioners and dehumidification of dehumidifiers. The key to choosing dehumidification methods is to take into account the dehumidification effect and economy. (end)

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