Performance research of solar hybrid desiccant cooling systems

Two types of hybrid systems are investigated here. One was composed of vapor compressor and desiccant (VC+D) cooling system, and the other was composed of vapor compressor, desiccant and direct evaporative cooler (VC+D+EC) cooling system. The system regenerated by electricity and solar energy was conventional and solar hybrid systems respectively. Mathematical model of rotary desiccant wheel was established by considering thermal storage of supportive structure, and the physical model and numerical model of the hybrid system were established too. It was found that under the same operating condition, compared with conventional vapor-compression (VC) cooling system, Coefficient of performance (COP) and energy saving of two VC subsystem for hybrid systems are increased 16.09%, 28.71% and 58.37%, 78.71%; energy saving of whole loads for conventional hybrid and solar hybrid systems are 11.76%, 20.51% and 38.22%, 53.62%. It was also found that with the inside design temperature increased and relative humidity unchanged, energy saving potential of VC subsystems and of the whole loads for conventional hybrid and solar hybrid cycles was strengthened. The performances of the two hybrid cycles were studied in some typical area of China. The results show that more energy was saved in hot, dry climates and less was saved in hot, humid climates for the conventional hybrid cycles, while the solar hybrid cycles always saved more energy than conventional VC cycles. (C) 2011 Published by Elsevier B.V. Selection and/or peer-review under responsibility of National University of Singapore.