The sun is one of the oldest energy sources, and scientists and engineers have been trying to harness the power of sunlight for a wide range of heating, lighting and industrial needs. In the United States, heating, ventilation and air-conditioning (HVAC) systems account for 30 percent of the energy used in commercial buildings and nearly 50 percent of the energy used in residential buildings.
Scientists at the West Central Research and Outreach Center (WCROC) are examining various ways to use solar energy. We collect data from these systems in order to evaluate the energy and economic performance as well as to establish baseline performance for future optimization.
Flat-plate collectors have an insulated panel that contains a dark absorber plate behind the outside panel. Water is heated as it passes through tubing inside the collector. The flat-plate system at the WCROC provides hot water to the Administration building.
Evacuated Tube Collectors
Evacuated tube collectors work something like a thermos; liquid water is located at the core. Surrounding the water is a heat pipe that traps the heat as the sun warms the liquid. The hot vapor rises to the top of the heat pipe where it can be channeled into a building to be used. The system at the WCROC is designed to provide 15 tons of space heat for a portion of the WCROC Administration building.
Solar cells, also called photovoltaic (PV) cells, convert sunlight into electricity. PV systems are found everywhere from wristwatches to airplanes to home and business use. Although solar energy continues to account for less than 1 percent of the U.S. energy supply, its contribution is expected to rise dramatically in the coming years.
Solar Use in Livestock Production
The swine facilities at the WCROC are used to model and demonstrate potential energy-efficient retrofits, including the installation of a 27 kW solar PV system on the roof of one of our finishing barns. Eventually, on-site renewable electric generation could supply some or all of the electric load thus allowing the building to approach net-zero (producing as much energy as is used).
Air conditioning can be produced from hot water via a sorption chiller. Water will remove heat from a cooling circuit when evaporated in order to be absorbed into a liquid salt solution or adsorbed on to a solid desiccant.
The solar air conditioning system at the WCROC uses a 10 ton absorption chiller. It is energized by hot water (158-203 degrees F) and the condenser is cooled with a wet cooling tower.
Learn more about solar thermal systems in the following hand-outs (PDFs):