Al-Ibrahim, A.M.; Beckman, W.A.; Klein, S.A.; Mitchell, J.W.
December 1998
Solar Energy, vol 64-4, p. 227-239
A search methodology for the optimum configuration of a photovoltaic pumping system in a solar domestic hot water (PV-SDHW) system is presented. The main premise of this methodology is the decoupling of the optimum search process in two phases. In phase one the goal is to find, among the possible PV pumping systems' flow rate profiles, the profile that maximizes the performance of a given SDHW system. In phase two the goal is to select the components of the PV pumping system. Each combination of PV cells, DC-motor and pump exhibits a unique flow rate profile. Therefore, the problem in this phase is to identify the PV pumping system components that results in the best match to the optimum flow rate profile found in phase one. This decoupling considerably eased the process of optimal search. An analysis of actual flow rate profiles of PV pumping systems showed that the optimum search can be restricted to the family of profiles represented by an experimentally-validated generalized function dependent upon three parameters only. Three PV-SDHW systems were considered and the optimum search methodology applied. The three systems are: (i) direct PV-SDHW system employing a PV array, a DC-motor, a rotary pump, a thermal collector, and a storage tank, (ii) and (iii) indirect PV-SDHW systems employing similar components to those in the direct PV-SDHW system in addition to either a forced or a natural convection heat exchanger to transfer the energy from the collector-side fluid to the tank-side fluid. Three DC-motors were considered; (i) series excited, (ii) permanent magnet, and (iii) separately excited.
Source: www.sciencedirect.com