With the development of modern society and economy, people have higher and higher requirements for the air temperature and humidity in the industrial environment.
Constant temperature and humidity environment control equipment should be used more and more widely. Refrigeration accessories and electrical control components are designed and manufactured completely in accordance with European industrial standards, which are reliable, efficient, and precise in control.
The unit is widely used in workshops, exhibition halls, archives, and laboratory places in various industries to create an industrial air-conditioning environment with precise constant temperature and humidity.
One: Constant temperature and humidity classification:
1. Laboratory decoration: It requires strict thermal insulation and moisture insulation performance. It is recommended that the four facades of the laboratory use color steel composite panels.
PE insulation boards are used on the top and bottom surfaces for thermal insulation and moisture-proof treatment; for see-through windows, double-layer vacuum glass windows are required.
2. Laboratory air conditioner: Laboratory air conditioner is the heart of temperature and humidity control, requiring high precision and low failure rate. Therefore, the air conditioner must be required to adjust the cooling capacity. There are two ways on the market: one is frequency conversion adjustment; the other is chilled water adjustment.
Frequency conversion adjustment: In fact, the compressor power is changed by changing the nature of the power supply, so that the compressor can achieve low load or overload work, and at the same time adjust the throttling flow of the refrigeration system, so a lot of cumbersome links must be added, and each link It must be a perfect match, otherwise it will malfunction. The reality is indeed the case, the failure rate is very high.
Chilled water type unit: Using cold water at around 7℃ as the cold source, the electric valve is opened or closed to control the water flow, thus easily controlling the cooling capacity, and the electric valve structure is as simple as a household faucet, so the failure rate is almost zero , The control effect is the most stable. By reasonably calculating the heat and humidity load and air dew point of the room to match the air volume, cooling volume, heating volume, and humidification volume, the stepless adjustment of each component is controlled by PLC, and the sensor with high sensitivity and good linearity can be selected to achieve temperature ± 0.1℃, humidity within ±1%. This method requires calculation and matching based on the actual area and load of each laboratory, so there is no standard molding unit, all of which are customized processing types. Generally, it is realized by the combination ratio of the combined air-conditioning box, so the disadvantage is that it occupies a large area.
3. Ventilation method
The ventilation method has gone through several historical stages, from the initial air outlet at the bottom, to the natural air supply at the top, to the air supply from the upper diffuser, to the most advanced air duct + micro-perforated ceiling air supply, and the lower floor return air method. The air supply throughout the laboratory is soft and uniform, and the temperature and humidity control is very stable.
4. Fresh air system
The first function of the fresh air system is to provide the staff with physiological fresh air. It also contributes to the stability of the laboratory temperature and humidity. It is also an indispensable equipment: in order to protect the laboratory from external interference, it must be provided to the laboratory. Provide fresh air to keep the laboratory pressure positive, so that outside air cannot enter the laboratory, and ensure that the laboratory's temperature and humidity are stable throughout the year.
Two: Principle of constant temperature and humidity:
The operation of the constant humidity and humidity machine system is through three interconnected systems: refrigerant circulation system, air circulation system, and electrical automatic control system.
Refrigerant circulation system: The liquid refrigerant in the evaporator absorbs the heat of the air (the air is cooled and dehumidified) and starts to evaporate. Finally, a certain temperature difference is formed between the refrigerant and the air, and the liquid refrigerant is completely evaporated and becomes gaseous. After being sucked by the compressor and compressed (pressure and temperature increase), the gaseous refrigerant absorbs heat through the condenser (air-cooled/water-cooled) and condenses into a liquid. After throttling through an expansion valve (or capillary tube), it becomes a low-temperature and low-pressure refrigerant and enters the evaporator to complete the refrigerant cycle process.
Air ring system: The fan is responsible for inhaling air from the return air inlet, and the air passes through the evaporator (cooling, dehumidifying), humidifier, electric heater (heating) and then sent to the space required by the user through the air outlet, and the air sent out is in the space. The mixed air returns to the return air vent.
Electrical automatic control system: including power supply part and automatic control part.
Through the contactor, the power supply automatically controls the power supply of compressors, fans, electric adders, humidifiers, etc. The sub-parts are divided into temperature and humidity control and fault protection parts: temperature and humidity control are controlled by temperature and humidity controllers. The temperature and humidity of the return air are compared with the temperature and humidity set by the user, and the compressor (cooling, dehumidifying), humidifier, electric heating (heating) and other components are automatically operated to realize automatic control of constant temperature and humidity.
