Optimization of solar and heat pump complementary powered desiccant air conditioning system

The effective utilization of renewable heat sources is critical for energy saving in desiccant air conditioning systems. A new solar and heat pump complementary powered desiccant air conditioning system is proposed. The system consists of a solar and water source heat pump complementary reheat subsystem, a two-stage desiccant wheel, a three-stage air cooler, and a two-stage heat pipe exchanger. Simulation are performed in the transient simulation software TRNSYS, and the particle swarm optimization and the Hooke Jeeves algorithm with life cycle cost as the objective function are applied to optimize the collector area, the heat storage tank volume and the water-source heat pump power. The results show that the monthly average coefficient of performance of the system is 5.1, 5.6, 5.5 and 4.8 in June, July, August and September, respectively. Compared to the conventional air conditioning system, the new system has a 58.4% reduction in operation cost and a payback period of 6.6 years. The CO2 emission reduction rate of the new system can reach 65.2% in July and 65.1% in August, while it is the lowest in September at 62.9%. Based on the above, the new system has better energy efficiency, economic and environmental benefits.