Pre-cooling type all-air system units from AOLAN

Pre-cooing Type All-air System Units

Working Principle

Liquid Desiccant Air Conditioning Technology

1,Characteristics of Hydrated Salt

In usual condition, as the desiccant of liquid dehumidification, the hydrated salt ( LiBr, LiCl, CaCl2) can not be decomposed and volatilized, and with low vapour pressure on surface, it has great hygroscopic capacity.

The hygroscopic capacity of hydrated salt will increase as its concentration increases, but decrease as the temperature rises. Greater hygroscopic capacity means great moisture absorption and heat release.

Hydrated salt will crystallize in certain temperature and concentration. When concentration is beyond a certain level, it will crystallize in normal temperature.

Hydrated salt has some certain corrosivity for metal.

2,Hydrated Salt Dehumidification and Regeneration Principle

Taking hydrated salt as working medium, liquid desiccant air conditioning technology (LDAC) uses the solution’s moisture absorption and releasability to realize the air humidity’ adjustment. The driving potential for water transfer comes from the differences of the hydrated salt’s partial vapor pressure and the air’s partial vapor pressure. When the solution’s surface vapor pressure is lower than the partial vapor pressure in air, the solution will absorb the vapor in air, that is, the air is dehumidified, on the contrary, when the moisture in the solution comes into air, the solution will be concentrated and regenerated. In the left picture (dehumidifying side), the treated partial vapor pressure is larger than the solution’s partial vapor pressure, to make use of their differences, the water vapor will be transferred from air to the solution, thus, the solution becomes dilute. In the right picture (regeneration side), the process is on the contrary.

3,Hydrated Salt Dehumidification and Regeneration Process

2-4 Regeneration Process: 2-3 is heat recovery temperature drop process, 3-4 is heating and regeneration process;

 4-2 Dehumidification Process: 4-1 is heat recovery temperature rise process, 1-2 is temperature drop dehumidifying process.

4,Technical Characteristics

strong (deep) dehumidifying ability;

the temperature and humidity in state point can be precisely controlled and there is no need to re-heat;

With filtering, bacteriostat, sterilization function, the removal rate for dust, bacteria, virus can be 92% - 95% without any other cost. 

Notes:
1.Nominal cooling and dehumidification working conditions: fresh air dray bulb temp.35℃,wet bulb temp.27℃;return air dry bulb temp.25℃,RH 25%; supply air dry bulb temp.10.8℃,RH 25%
2.Runing environment: clean plant with retaining structure, story height less than 2.5m
3.Auxiliary electric heat device is optional, suitable for devices which need to run whole year.