The design of high-precision constant temperature and humidity laboratories has certain requirements. Only by following the following principles can high-precision constant temperature and humidity laboratories be better utilized.
Design principle 1 of high-precision constant temperature and humidity laboratories:
1. Under the premise of meeting a certain heat transfer coefficient X, the enclosure structure of high-precision constant temperature and humidity laboratories should consider a certain thermal inertia when selecting materials to resist the influence of unstable heat flow from the outside. When the constant temperature accuracy is required to be high, a heavy enclosure structure with greater enthusiasm should be used. In addition, the moisture-proof and vapor-proof measures of the enclosure structure are also extremely important, otherwise the water vapor penetration caused by the partial pressure difference of water vapor inside and outside is difficult to control.
Design principle 2 of high-precision constant temperature and humidity laboratories:
2. On the periphery of the high-precision constant temperature and humidity chamber, it is best to have a low-precision constant temperature chamber as its outer room or suite. In this way, the high-precision constant temperature and humidity chamber will not be affected by external climate changes, and the indoor temperature and humidity fluctuation range will be reduced, so that the control system can work more stably and it is easy to ensure the accuracy requirements. In addition, it can also be made into a return air interlayer as shown in the figure, and the return air of the constant temperature and humidity chamber itself can be used to surround the constant temperature and humidity chamber to reduce the influence of unstable heat sources from the outside.
Design principle three of high-precision constant temperature and humidity laboratory:
3. Whether there is a suite or not, the constant temperature and humidity room should be arranged on the north side and the ground floor of the building as much as possible. It is not advisable to have an outer wall, doors and windows facing east or west to reduce the influence of solar radiation heat. When the constant temperature accuracy is soil (0.1-0.2)0C, there should be no outer wall. In addition, in order to reduce the impact of drastic changes in outdoor meteorological conditions, high-precision constant temperature and humidity rooms are sometimes arranged in basements, which can also reduce the load, save air conditioning investment and operating costs, and is also beneficial to improving the thermal stability of constant temperature and humidity rooms. However, this arrangement will increase civil engineering costs, especially in areas with high groundwater levels. Due to the difficulty of waterproofing, this solution is often not adopted.
Design principle four of high-precision constant temperature and humidity laboratory:
4. It is best not to open windows in high-precision constant temperature and humidity rooms. If windows have to be opened due to lighting, sanitation or building treatment needs, the outer windows should be opened on the north wall where the solar radiation heat is weakest, and double-layer sealed windows should be used. When the constant temperature accuracy is ±(0.1-0.2)℃, there should be no external windows. The door of the high-precision constant temperature and humidity chamber must be made into a sealed door filled with insulation material, and a door vestibule should be set at the external door. When the constant temperature accuracy is ±(0.1-0.2)℃, it is strictly forbidden to have an external door. In order to prevent outdoor air from infiltrating into the room through doors and windows, the indoor air needs to maintain positive pressure.
    In order to minimize the interference of external climatic conditions, some special considerations must be made in the construction treatment of the high-precision constant temperature and humidity chamber. This is not only conducive to ensuring a certain constant temperature accuracy, but also has important economic significance for the investment and operating costs of air-conditioning equipment.