Dynamic simulation and parametric sensitivity studies on a central solar domestic hot water system

A computer simulation program for a central solar domestic heat water (DHW) system has been developed and validated by comparing it with the actual performance data obtained from a real-life system. A computer simulation language, CSMP, was used for the simultaneous solution of the differential equations describing the system. The program was developed from basic principles and defined parameters. It was utilized to study the dynamic behavior of the system and to perform parametric studies to determine the effects of various system parameters on its performance. Parametric sensitivity studies were carried out to determine the response of the central solar DHW system performance to the following parameters: flow rate of heat-exchange fluid in the solar collector loop, consumption rate in the consumer loop, start-up time (i.e., activation of the collector loop circulation pump), and storage tank capacity. The concept of consumption management is analyzed and discussed in order to emphasize the fact that solar loop productivity, both qualitative and quantitative, is not independent of load. As a corollary, we show that it is possible, when the situation allows, to maximize solar loop productivity by controlling the consumer loop consumption schedule.