The constant temperature and humidity air conditioner with control accuracy of ±1.0℃ and ±2.0% is called high-precision constant temperature and humidity air conditioner. Because this type of air conditioner is mostly used in laboratories in fields that are particularly sensitive to temperature and humidity, such as papermaking, textiles, pharmaceuticals, tobacco, electronics, and measurement, it is also called laboratory-specific air conditioner.

The difference between high-precision constant temperature and humidity laboratory air conditioners and ordinary computer room air conditioners:
1. High-precision constant temperature and humidity laboratory air conditioners must have high-precision temperature and humidity sensors, requiring sensors
Accuracy: ±1.5%RH, ±0.3℃ (at 23±2℃)
Repeatability: better than 0.5%RH and 0.1℃
Stability: better than 1.0%RH and 0.1℃ per year
And the sensor accuracy of ordinary computer room air conditioners is ±3%RH, ±1℃ is enough;
2. High-precision constant temperature and humidity laboratory air conditioners have higher requirements for air volume. Theoretically, the larger the air volume, the smaller the air supply enthalpy difference, and the more uniform the temperature and humidity; however, the larger the air volume, the smaller the dehumidification capacity, or even completely lost. Therefore, high-precision constant temperature and humidity air conditioners require as large an air volume as possible on the basis of ensuring dehumidification capacity, and the design of air volume is very strict, while ordinary computer room air conditioners have lower requirements.
3. High-precision constant temperature and humidity laboratory air conditioners require adjustable heating, cooling, humidification, and dehumidification capacity. Due to the accuracy requirements, high-precision constant temperature and humidity laboratory air conditioners require adjustable heating, cooling, humidification, and dehumidification capacity.
(1) For heating, multi-stage heating is used for adjustment according to the temperature difference. When the temperature difference is small, only the first stage of heating is turned on. When the temperature difference is slightly larger, the 1st and 2nd stage heating are turned on at the same time. When the temperature difference is larger, the 1st, 2nd and 3rd stage heating are turned on at the same time.
(2) For humidification, proportional humidification is used to control the humidification amount according to the humidity difference.
(3) For the adjustment of cooling and dehumidification, there are three adjustment methods:
1) The first generation adjustment method uses multi-stage cooling, which is generally used for high-power equipment and is mainly used for temperature adjustment. It has little effect on humidity adjustment.
2) The second generation adjustment method uses variable frequency cooling, and the cooling capacity is between 50% and 100% to achieve stepless cooling adjustment. This adjustment range is sufficient to solve the problem of temperature and humidity stability. It is used for high-precision constant temperature and humidity laboratory air conditioning, and the effect is remarkable. However, due to control needs, many auxiliary control links need to be added, and the various accessories must be closely coordinated. A slight fault in a link may cause damage to important components such as compressors due to chain reactions.
3) The third generation of regulation, chilled water type refrigeration, uses chilled water (designed according to the general central air conditioning water temperature) as the cold source. The coil runs ordinary cold water at about 7°C. The computer motherboard easily achieves 0% to 100% stepless adjustment of cooling capacity by controlling the opening of the water valve. Moreover, the integral valve structure is as simple as a household faucet and has a very long service life. However, the equipment requires a lot of maintenance and is difficult to repair after problems occur. It is recommended to avoid using it as much as possible.