Solar Panels are just one of the ways that solar energy can be utilized. Lately, our Building Analyst, Dane Ervick, has been learning about solar thermal technology.
Solar Thermal Water Heating in a Nearly 200 year-old Home
The latest phase of the large scale energy efficiency improvement of the 1821 Daniel Beard Home in Covington, KY involved the installation of a solar thermal water heating system. Dane was on the roof overseeing Intercept Restoration’s installation as part of our Contracting Service.
SOLAR THERMAL TUBES
Solar thermal relies on a system of tubes to capture solar energy. A solar thermal tube consists of an inner glass tube coated in a reflective material which is enclosed in a transparent glass outer tube. A vacuum is created between the tubes which reduces heat loss and increases efficiency. The tubes are installed on the roof and filled with a water/coolant mixture.
THE SOLAR THERMAL PROCESS
The sun heats the mixture in the tubes (#1 on the above illustration) which is then transferred via a solar powered electric pump (#2) to a water storage tank (#3 ,which looks like a typical water heater) located in the basement. In the storage tank, heat is transferred to potable water through a heat exchanger, which renders the potable water hot and ready for use (#4). The cooled water/coolant mixture is then cycled back to the rooftop tube installation to start the process over (#5).
In the Daniel Beard home, the homeowner designed the solar water heating system to pre-heat water that can then be fed into a natural gas heated instantaneous water heater. This design allows the gas water heater to bring the preheated water up to the desired temperature at night or on cloudy days while ensuring that the majority of the heat will be supplied by a free and renewable resource.
With the sun heating the water and providing the power for the water pump, energy costs for heating water will be almost completely eliminated. After installation, water heating bills can drop 50-80%.
Solar Stoves: Portable Renewable Energy
Solar thermal technology came up again while Dane was speaking about energy efficiency for the 8th Annual Winter Permaculture Design Certification class provided by www.this-land.org. On this particular day, the class was being held in the home of a past client of the Energy Alliance’s Contracting Service program.
THE GOSUN STOVE
Before his presentation, Dane heard a presentation from GoSun, about their portable oven which uses solar energy to cook. After getting a closer look, Dane realized that the portable oven was essentially an empty version of the solar thermal water heater tube he had just seen on top of the Daniel Beard house.
Instead of heating a water/coolant mixture, the sun heats your food!
“Seeing the many creative ways that we can harness the power of a resource that is so ubiquitous makes me very excited to see what the future holds for this technology.”
Dane Ervick, Energy Alliance Senior Operations Associate and Building Analyst