SOLAR THERMAL FREQUENTLY ASKED QUESTIONS
What is solar thermal?
Solar thermal is a technology that utilizes the sun’s energy to generate heat, which is then used to heat (or cool) water or other fluids for a variety of applications.
What is the difference between solar thermal and photovoltaic (PV) solar technology?
Solar thermal systems generate heat whereas photovoltaic (PV) solar systems generate electricity.
Why would I choose solar thermal or solar water heating?
Solar thermal and other solar water heating systems (solar pool heating) are highly efficient and work year-round. These systems heat your water before it enters your hot water tank or pool. Free heat of the sun provides significant annual energy savings.
How does the conversion of solar energy to heat in a glycol-based system work?
Solar radiation hits the absorber of the solar collector is transferred to the heat transfer medium (a propylene glycol solution, usually) and that now heated solution is circulated through a heat exchanger providing heat energy to the system.
What type of businesses can benefit from solar thermal?
Solar thermal can benefit any business or facility that relies on large quantities of hot water or other heated fluids. Organizations facing sustainability mandates from shareholders or the government can also benefit from solar thermal.
How much money will a solar thermal system save me?
Savings vary depending on system size, application and how energy is being used in the building. A site analysis is the first step toward reaching an accurate, project-specific figure on system savings.
How much of my yearly hot water load will a solar thermal system offset?
Appropriately sized systems can offset 60-80% of the annual hot water load.
Can a solar thermal system work with an on-demand water heater?
Yes, a solar thermal system can work with an on-demand water heater. This is a good solution for projects with space limitations.
Can’t I just use solar electric (PV) to offset my hot water load?
For a very high cost. You would pay over five times more to heat your water with a solar electric (PV) system and use over six times the roof space. A better solution is a solar water heater with an electric back-up that can be offset by a PV system.
What is Concentrated Solar Power (CSP)?
CSP solar thermal systems are generally large-scale installations that use lenses or mirrors to focus solar rays onto a reservoir of fluid. The fluid boils, creating steam that can power a turbine, which produces electricity.
What is the Solar Tax Credit?
The Investment Tax Credit (ITC) is currently a 30 percent federal tax credit claimed against the tax liability of residential (Section 25D) and commercial and utility (Section 48) investors in solar energy property. The Section 25D residential ITC allows the homeowner to apply the credit to his/her personal income taxes. This credit is used when homeowners purchase solar systems outright and have them installed on their homes. In the case of the Section 48 credit, the business that installs, develops and/or finances the project claims the credit.
A tax credit is a dollar-for-dollar reduction in the income taxes that a person or company claiming the credit would otherwise pay the federal government. The ITC is based on the amount of investment in solar property. Both the residential and commercial ITC are equal to 30 percent of the basis that is invested in eligible property which have commence construction through 2019.
Is there a difference between solar thermal and solar water heating?
Yes. The Solar Guide uses solar thermal as a catch-all term, but it is important to note that solar thermal and solar water heating fall into three or more very different types of systems:
- Solar thermal water heating systems heat water. They do this using heat exchange or by directly heating the water. For more information, see The Solar Guide's section on solar thermal.
- Solar pool heating heats water for your pool or hot tub. See our section on solar pool heaters.
- Solar thermal also applies to solar floor heating and space heating and cooling.
How does a solar thermal system work?
Collectors (panels) mounted on a roof or on a ground-mounted structure absorb solar energy. Solar-heated fluids are circulated through the collector transferring thermal energy to water stored in solar storage tanks that feed(pre-heat) the primary water-heating system. When pre-heated by with solar-heating system, the backup water-heating system is either not activated or activated for less time.
How can solar thermal benefit a business?
The two main benefits of solar thermal for commercial clients are reduced energy bills and reduced carbon footprint. A solar thermal system provides long-term financial benefits by reducing monthly utility bills while also helping you go green.
How many solar thermal panels would I need to heat water for my home?
You can get the best answer to this by contacting a solar thermal dealer. This will depend on how many people in your household, on how much hot water you use and how much sunlight you receive.
How much does a solar thermal system cost?
As with any business investment, there is an upfront cost to installing a solar thermal system. Power Purchase Agreements, and various rebates and tax credits, can remove or substantially reduce the upfront cost. Over time, the money that the system saves you adds up to several times the system cost. A site analysis is the first step toward reaching an accurate, project-specific figure on system cost.
Will my building still have hot water on cloudy days, or if the system breaks down?
Yes, the building with solar thermal heating systems will still have hot water despite clouds or inclement weather. Because solar thermal systems supplement the building’s existing water-heating equipment (i.e., a boiler) the building will always have hot water.
If I install a solar thermal system, can I keep my regular water heater?
Typically, yes. There are systems available that combine a solar hot water tank and a natural gas-powered water heater.
Do the solar thermal collectors (panels) need to face due south?
No. Though due south is ideal in the northern hemisphere, the collectors can be installed up to 90 degrees off of due south with minimal impact on energy production.