Solar collectors like this one are part of a solar water heating system

Looking to save money on your electric bill?  Even if you think you cannot afford solar photovoltaic panels (PV panels) to generate electricity, you could still use a solar water heater.

Some solar domestic hot water systems are very affordable.  Using energy from the sun to heat water for residential uses – bathing, washing dishes, laundry and more – means you don’t need to rely on electricity or gas for hot water.

This post will review passive solar water heating systems.  Generally more affordable and less complex than the solar water heaters that use pumps and other controls.  A passive solar water heater requires a storage tank and a solar collector.  You will also need a back-up system for increased demand or when there is low UV light.

Solar collectors are generally comprised of plate glass and a series of glass tubes in which the water flows and is heated by UV light striking the surface of the collectors.  There are several different types of solar collectors, depending on your climate and hot water needs.

Use a solar water heater to minimize electricity costs associated with hot water

As noted above, a passive solar water heater is less expensive and complex than an active pump system.  They are also more reliable and may last longer.  Great news for your solar investment!

Just as with the types of solar collectors, you’ll want to pick a type of passive system that makes the most sense for your geographic location and hot water needs.   The type of solar water heating system that is most often used is a thermosiphon system.  The best way to illustrate the system is in the video below:

On the other hand, if you go with an integral collector-storage system, you’ll need to live in an area where temperatures rarely drop below freezing.

How do you know whether to use a solar water heater, or which system is best for you?  Consider the following:

• Average UV light exposure
• Residential hot water needs
• Annual electricity and/or gas bills
• Whether there are any zoning regulations or homeowner association rules that regulate or prohibit rooftop installations

While you could try your hand at a DIY solar hot water system, we recommend hiring a professional solar thermal system contractor.  Passive solar hot water installations require little maintenance after installation.  Simply turn on your hot water and enjoy the fruits of solar energy!

National Renewable Energy Laboratory

The National Renewable Energy Laboratory (NREL) is the primary laboratory for renewable energy and energy efficiency research and development in the United States.  Based in Golden, Colorado and with offices in Washington D.C., NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy.  It is operated by the Alliance for Sustainable Energy.

NREL has been operating since 1977, initially as the Solar Energy Research Institute. In 1991, the name was changed to NREL when it was designated a national laboratory by the DOE.

Solar research is one of the primary programs at the National Renewable Energy Laboratory.  Its Solar Energy Technologies Program advances research and development in several major solar technologies.

NREL's laboratory in Golden, Colorado

NREL’s Solar Energy Technologies Program includes research on photovoltaics (PV), solar thermal, and solar radiation.

Perhaps the technology with which most people are familiar is photovoltaics.  Say the term “solar power,” and the first thing that comes to mind is usually silicon-based PV cells, or solar panels.  At NREL, advancements are being made with respect to performance and reliability of PV cells.  It is developing standardized tests and performance models to help the industry, and working to accelerate manufacturing capacity of PV technologies.

This research can only be helpful if it can be transferred to the marketplace.  As described on the official NREL website:

“A critical part of the Lab’s mission is the transfer of NREL-developed technologies to renewable energy markets. NREL’s Technology Transfer Office supports laboratory scientists and engineers in the successful and practical application of their expertise and the technologies they develop. NREL’s world-class R&D staff and facilities are recognized and valued by industry, as demonstrated through hundreds of collaborative research projects and licensed technologies with public and private partners.”

Another area of solar research at NREL is focused on solar thermal.  Concentrating solar power is an alternative way to generate solar electricity that uses mirrors to superheat water to create steam, which then turns generators.  Also known as parabolic trough technology, CSP is used in Spain, Portugal and at some California and Nevada locations to generate utility-scale solar energy.

On a smaller scale, NREL is also working to improve efficiency and lower cost of solar hot water systems.  These can be installed on homes and businesses to provide hot water, without the use of electricity.  At NREL, researchers are working to develop new polymer (plastic) systems for solar water heating.

Solar radiation research is necessary to determine the optimal siting of solar panels or parabolic trough technologies.  At NREL, data on solar radiation and other meteorological information is collected at the Solar Radiation Research Laboratory and provided to certain organizations, universities and governmental agencies.  That information is then used for climate change models, testing renewable energy conversion systems and general atmospheric research.

Research at NREL spans the range of renewable energy options, beyond just solar power.  For more information about what is happening at the National Renewable Energy Laboratory, click here.