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Solar Thermal

Solar thermal applications can be simple, cost effective, and diverse for research campuses.

The following links go to sections that describe when and where solar thermal energy may fit into your climate action plans.

Campus Solar Thermal Energy Options

There are a number of ways to use solar thermal energy on campus. These systems use air, water, or oil to deliver energy collected from the sun to buildings for heating, hot water consumption, or process heat for research. On-campus applications include:

  • Solar ventilation preheating, which warms fresh air before it enters the building for ventilation. Solar air collectors operate at near ambient temperatures and are among the least expensive of all renewable energy technologies to install.
Photo of a man in a red shirt standing in front of a black, corrugated, transpired (with holes in it) solar collector that runs the length of the photo from bottom to top.
  • Solar hot water systems heat water for laboratory and commercial building use. They operate at the same temperatures as most hot water distribution systems in buildings: about 120°F. These are the most common and cost-effective installations worldwide, and can work well on many campuses. For a system serving a single building, the collectors are often located out of sight on the roof.
Photo of a woman and three men standing in front of three solar collectors installed on a flat white roof of a large building.
Photo of a field of concentrating solar collectors in the foreground with a large building with a dome on top of it in the background.

Solar thermal systems are technically simple and require little maintenance. High-quality components are readily available and the skills needed for installation and maintenance are similar to those of other energy systems. These systems can be integrated within building structures in new construction or can be added on during retrofit projects.

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Campus Solar Thermal Considerations

Is solar thermal right for your campus?
  • Do you have a good solar energy resource?
  • Are the rooftops flat or south-facing?
  • Is open land available?
  • Do you want to demonstrate a commitment to renewable energy?
  • Are incentives and rebates available?
  • Is financing available?

Research campuses should consider the following before undertaking an assessment or solar thermal energy installation.

Solar Energy Resources

Solar energy production varies significantly from one site to another. An expert should be consulted to perform a resource assessment before any installation is undertaken.

For feasibility and scoping studies, the National Renewable Energy Laboratory (NREL) publishes low- and high-resolution solar energy resource maps of the United States. These maps connect with a geographical information system that enables you to zoom in on specific locations.

RETScreen can further determine available solar thermal resources. The tool helps campuses predict solar thermal energy production at a specific location.

Siting

Solar thermal systems are typically installed on flat or south-facing building rooftops. Systems are often integrated into buildings or atop structures such as parking garages, requiring little to no additional land use. Systems can also be erected on adjacent open land.

Building-integrated systems are important for all research campuses, but are particularly critical in urban areas. If solar thermal is not installed with the building during construction, a building can still be designed and constructed to be solar ready with roof exposures and slopes that accept solar collectors.

Visible Commitment to Sustainability

Solar thermal collectors showcase a commitment to sustainable renewable energy. Many systems are installed in ways that are not apparent, but they can be positioned as visible reminders of your research campus's commitment to climate neutrality.

Incentives and Rebates

Many states, municipalities, and serving utility companies offer incentives and rebates for renewable energy projects. The programs can dramatically reduce capital costs associated with project development. Check the Database of State Incentives for Renewables and Efficiency to see whether your state provides incentives or tax credits for renewable energy installations.

Financing

Although the "fuel" is free, solar thermal installations require a capital commitment, so financing can be a critical factor in determining the feasibility of a particular project. You can compare energy cost and performance data for solar energy and other renewable energy technologies; NREL compiles these data from a variety of sources and publishes them online.

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Leading Example: Sample Solar Thermal Project

Photo of numerous concentrating solar thermal collectors in a desert setting with scrub brush and mountains fading into the background. The collectors are shimmering mirrors harnessing the sun's rays.

Concentrating solar thermal systems for hot water applications deliver large-scale hot water applications, like this system at the Phoenix Federal Correctional Institute in Arizona.

The Phoenix Federal Correctional Institution in Arizona is not a research campus, but is a best practice example of large-scale solar hot water application. A large concentrating solar thermal system provides 70% of the facility's annual hot water needs, producing up to 50,000 gallons of hot water daily. The U.S. Department of Energy (DOE) Federal Energy Management Program published a fact sheet titled, "Heating Water with Solar Energy Costs Less at the Phoenix Federal Correctional Institution".

The system is remarkable for several reasons:

  • Scale: The system includes 17,000 square feet of solar thermal collectors that generate 13 million British thermal units of energy each day.
  • Scope: Concentrating collectors provide high-temperature water for laundry and kitchen applications as well as showers.
  • Longevity: The system has been functional for more than 10 years.
  • Verification: The system is extensively monitored with several years of measured data published.
  • Delivery Method: The system was installed using an energy savings performance contract to finance the installation and provide annual cost savings.

Other Examples on Campus

The following list highlights examples of use of solar thermal applications on campus, especially on dormitories.

  • Eastern Mennonite University in Harrisonburg, Virginia, is building the new Cedarwood Dormitory with solar hot water collectors that will provide 50% of the energy for domestic hot water for the building.

  • Harvard University in Cambridge, Massachusetts, installed solar hot water systems on two dormitory buildings in the spring of 2009 that each provide 30%–40% of the energy for domestic hot water at those facilities. Harvard presents some preliminary performance data on its Web site.

  • Williams College in Williamstown, Massachusetts, uses an evacuated-tube solar collector that effectively heats water in cold climates.

  • Guliford College in Greensboro, North Carolina is partnering with a private firm to install a total of 200 solar thermal collector panels in one of the largest solar-thermal systems ever installed on a U.S. college or university campus. Images of the installed system can be viewed in this slideshow.

  • Drury University in Springfield, Missouri, installed 10 solar collectors on the roof of Smith Hall Dormitory that combine solar water heating with electricity generation from photovoltaic cells.

  • Governors State University in University Park, Illinois, installed a solar hot water system in 2006 to heat its Olympic size swimming pool and provide domestic hot water for most of the university. At the time, it was the largest solar thermal installation in Illinois.

  • Dickinson College in Carlisle, Pennsylvania, provides heat to a greenhouse with solar energy.

  • Cochise College installed a unique solar parabolic trough cooling system in 2006.

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Technology Basics

The following resources explain the fundamentals of solar thermal technologies:

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