Design of a Solar Thermal Collector Simulator

Abstract

The rising cost of non-renewable energy resources has placed a large emphasis on alternative sources of energy to replace or augment society’s increasingly large demand. For residential energy use, the average water heating load consumes approximately 14% to 25% of the total energy demand. Usually this energy is supplied by electricity or natural gas. This significant portion of a single household’s energy draw, coupled with rising energy costs, provides a strong motivation for the implementation of residential solar thermal systems. The purpose of this project is to design and fabricate a simulator for a small solar thermal collector array that can be used to research improvements to solar thermal collector systems. A modified on-demand water heater in conjunction with LabVIEW control software comprises the simulator system. The heater component interfaces with a LabVIEW control panel that accepts collector geometry and specifications and then calculates the appropriate heater power to simulate array output for a given set of meteorological weather data. The heater delivers the specified amount of power to the working fluid, which is varied by power electronics using phase angle control. LabVIEW control software requests feedback from inlet and outlet thermistors in order to accurately calculate the available power to the collector and the useful energy gain. For a given set of meteorological data, the system provides the ability to repeatedly simulate the same output power conditions within 9% of theoretical calculations. The simulator will serve as a foundation to study future modifications to residential solar thermal collection systems.