Simulation analysis on the fresh air handling unit with liquid desiccant total heat recovery

A liquid desiccant fresh air processor is presented whose driven force is low-grade heat (65~70℃ hot water). Inside the processor, the desired cooling source for air’s dehumidification is indoor exhaust air’s evaporative cooling energy. Multi-stage structure is used to get higher total heat recovery efficiency of indoor exhaust air. The mathematical model of the fresh air processor is set up and realized by SIMULINK procedure. As the practical liquid desiccant fresh air processor is developed, its performance is tested with average COP (cooling load divided by heat source) 1.3. Besides, the inside detailed parameters of practical facility for each heat transfer unit are acquired through testing. By comparing the tested and simulated data, the mathematical model is corrected by changing the main heat transfer units’ characteristic coefficients, such as the volumetric mass transfer coefficient of  air-water evaporative cooling module and the KA of sensible heat exchangers. Finally, using the corrected simulation model, the control strategy of the fresh air-handling unit is discussed, which indicates the imported strong solution’s flowrate and the number of working stages are two effective regulated parameters and can be controlled singly or together at different outdoor conditions and for different indoor demands.