Constant temperature and humidity laboratory, the use of direct evaporative independent constant temperature and humidity of the air conditioning system, it has a simple system, easy to adjust, convenient operation and management, energy saving, etc. In engineering design, reasonable choice according to the precision of temperature and humidity requirements of laboratory system, as far as possible room load calculation of the selection and matching of constant temperature and humidity units in detail.

In order to meet the accuracy requirement of the indoor constant temperature and humidity, constant temperature and humidity air changes the size of air conditioning room, according to the experience, plus or minus 2 ℃ constant greenhouse, air changes about 10 ~ 15 times/h. + / - 1 ℃ constant greenhouse, ventilation rate of about 15 ~ 20 times/h. Greenhouse, plus or minus 0.5 ℃ constant ventilation rate > about 20 times/h. Greenhouse, plus or minus 0.2 ℃ constant ventilation rate > about 30 times/h.

Air distribution design is also one of the main factors affected the accuracy of thermostatic chamber, the high precision of constant temperature and humidity of indoor air distribution design should consider the principle: the reasonable air distribution process, give full play to the supply air cooling or heating effect; Establish a stable and uniform temperature field, to ensure that the airflow in work area, the average temperature and the temperature difference in the work place shall not exceed the allowed temperature fluctuation values; Airflow in work area, the flow velocity at about 0.25 m/s. Plus or minus 2 ℃ and + / - 1 ℃ high precision constant temperature and humidity laboratory, using orifice plate and local orifice plate air supply, lower return air, the effect is better.

In the constant temperature and humidity laboratory construction, its insulation sealing is also very important; Insulation sealing good laboratory with saving energy, improving the precision of temperature and humidity, to reduce the operation cost, etc.