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Photovoltaic Solar Water Heating System

NIST photovoltaic water heater

Laboratory: National Institute of Standards and Technology (NIST)

Technology: Photovoltaic Solar Water Heating System

Opportunity: This novel NIST technology is available in the public domain.

Details: These energy-saving computerized solar water heaters convert solar energy into electrical energy. By using the direct current supplied by the photovoltaic array and the inherent storage capabilities of a residential water heater, the photovoltaic solar hot water system eliminates the components most often associated with the failures of thermal hot water systems. This technology can be configured as a single- or double-unit system, and does not require an inverter to convert the DC supplied by the photovoltaic array to an alternating current or a battery system for storage.

Benefits: Aside from its adaptability to work either single- or double-unit systems, this technology is extremely energy-efficient and useful where other energy sources are unavailable or expensive. The system is also low cost in that it generates DC power, ultimately eliminating inverters or wide arrays of piping. 

Potential Applications: The Photovoltaic Solar Water Heating System can be used for remote water heating and is useful for locations such as vacation homes, agricultural applications or livestock watering troughs.

Contact: For more information about the Photovoltaic Solar Water Heating System, contact NIST’s Technology Partnerships Office at

To view the original fact sheet for this technology, visit