Modeling photovoltaic-powered solar water heating systems using trnsys

摘要

A photovoltaic-powered solar domestic hot water (PV-SDHW) system uses PV cells to generate electrical energy which is dissipated in several resistive heating elements within a water storage tank. A microprocessor controller selects the combination of resistors which maximizes PV array power output with respect to the incident solar radiation. Two fully-instrumented prototype installations are currently operating, one at the National Institute of Standards and Technology (NIST) in Gaithersburg, MD and the other at the Florida Solar Energy Center (FSEC) in Cocoa, FL. Both systems have a dual-tank design consisting of a PV-connected preheat tank delivering heated water to a utility grid-connected auxiliary tank for any additional heating. Simulation models of these systems have been constructed with the TRNSYS program and validated with experimental data. This paper describes the PV-SDHW system models and presents comparisons of measured and TRNSYS-predicted performance results.