Computer Modeling Of A Solar Thermal System For Space Heating

Most applications of flat plate, low-temperature solar thermal panels are for water heating, such as producing domestic hot water or raising the temperature of swimming pools. This is reasonable given that the large masses of water present in these systems inherently provide built-in thermal energy storage so that a separate energy storage tank does not have to be purchased. For a space heating system, extra thermal energy storage generally has to be purchased and is a detriment to the economics of these systems. Despite the economic drawbacks of solar thermal space heating, this thesis focuses on the size of thermal systems required to heat an average size home in Minneapolis, MN and Dayton, OH. For these two locations and for a standard test case, this thesis studies the effect of solar panel size and orientation, heat exchanger size, and operation parameters including flow rates through the solar panels and heat exchanger. Liquid, flat plate collectors are one of the simplest methods for collecting solar energy. These panels are generally inexpensive and can have collection efficiencies above 50%. This makes solar thermal panels more efficient than solar photovoltaic panels, which generally have efficiencies less than 20%. Since the solar thermal panels chosen for study in this work heat a liquid with the sun’s energy and the fluid being heated in the building is air, a heat exchanger has to be included in the model. Lastly, because solar thermal systems are inherently unsteady, thermal energy storage must be included in the model. These components of a solar thermal space heating system are modeled by writing and adding routines to the Wright State developed simulation program called Solar_PVHFC. Solar_PVHFC is a simulation program which models solar photovoltaic panels coupled with fuel cells and hydrogen storage tanks. Because of this work, Solar_PVHFC is now capable of modeling a solar thermal system. The advantage of coupling this solar thermal work to Solar_PVHFC is that Solar_PVHFC does a very detailed calculation of the solar energy impinging upon a surface at any location, at any time, for any orientation. This is required to properly model solar thermal systems. The program modules that perform the simulation of the solar thermal system components are written in MATLAB, just like the Wright State developed program Solar_PVHFC