Solar Thermal: Solar Thermal Vs Solar PV
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by ACEP UAF Introduction to Solar Thermal and Solar Photovoltaic Power Most people don’t even realize that there are two types of solar power. They just assume that solar thermal and solar photovoltaic are two names for the same type of energy. In a way, that’s true. Both types harness the energy of our sun, but are totally different. With thermal, sunlight is concentrated on a working fluid to produce heat to power a heat engine. That heat engine cranks a generator that produces electricity. There are numerous types of liquid and gas working fluids, such as water, air, oil, nitrogen, salts and helium. Additionally, the heat engine will most typically be a gas turbine, a steam engine or a Stirling engine. However, there are other kinds of heat engines that can be used. Heat engines have a high efficiency rating between 30 and 40 percent. They can produce up to hundreds of megawatts of power. Solar PV doesn’t involve a heat engine. Instead, it uses solar panels to directly convert sunlight into electricity. Solar PV only works when the sun is shining. It is ineffective at night or on cloudy days. Electricity is difficult to gather and save, which makes solar