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Solar Electric vs. Solar Hot Water Systems

Solar Water Heating System (left) and a PV Grid-Tied System installed by APEX Thermal Services for OnForce Solar, Cornwall, Orange County, NYSolar Water Heating System (left) and a PV Grid-Tied System installed by APEX Thermal Services for OnForce Solar, Cornwall, Orange County, NYThis discussion is meant to compare two types of solar energy systems.  Solar Electric Systems, often termed Photo-Voltaic Systems or PV Systems and Solar Thermal Systems, also known as Solar Hot Water Systems or Solar Heating Systems. 

Firstly, APEX Thermal Services is of the mentality that all solar energy systems are useful tools.  Tools we should make use of to reduce our dependance on utilities and fuel suppliers.  When the sun shines, your solar energy system generates and collects energy to reduce your costs.  It's a you-get-what-you-get situation.  When there is no sun, there is not much to be gained, but when the sun shines, you can get a lot!

At APEX Thermal Services, it is our goal to assist you in making the alternative-energy decision that is right for you.  We have spent many years in the energy-efficiency arena, and we know how to prepare an analysis to indicate what the financial results of these investments will do for your bottom line.  That is usually where the final decision is determined.

PV Systems use silicon cells to create electricity from sunlight.  Typically, PV Systems are configured and installed as Grid-tied systems.  Grid-tied systems are electrically installed across the existing electrical grid, and the bad news is: they actually shut down when there is a blackout.  Yes, all those beautiful collectors on the roof, and no output whatsoever, during a blackout.  PV Systems can also be used to charge batteries and these systems may or may not be associated with the electrical grid at all.  PV Systems with batteries are typically more expensive than conventional Grid-tied systems, because the number of batteries required for any significant solar energy storage can be quite expensive.  There are many grades of batteries that can be utilized for this purpose.  A group of some of the highest quality batteries could cost upward of $10,000 to $20,000.  You could utilize less expensive batteries, but you will need to change them much more often.  Typically, the cheaper the batteries, the sooner they will need to be replaced.

Solar Thermal Systems, also known as Solar Hot Water Systems, use dark or selective surfaces, under glass, in an insulated enclosure, to collect heat from the sun's radiation.  A water/antifreeze solution is circulated through the collectors which is also connected to a water storage tank in the mechanical room.  Over time, the tank temperature increases and ultimately reduce boiler or water heating fuel/energy consumption.  Basic systems usually provide domestic water heating only, while larger systems can contribute to pool heating, space heating, and especially radiant slabs and radiant heating systems!

Another type of solar thermal collector is specific to pool heating and is not intended for year round use.  For more on these specific solar pool heating collectors, visit our Solar Pool Heating page under the SERVICES tab.

Based on today's energy costs and solar energy system costs, Solar Heating Systems will usually provide a stronger financial return than today's more prevalent PV Systems.  Part of that advantage is realized by the efficiency of the collectors.  Solar hot water collectors are roughly 66% efficient in harvesting the sun's energy, while most PV panels are still below 20% efficient.  Many are below 15% efficient.  If you choose higher efficiency PV panels, they cost more.  The bottom line is that you need three to four times the PV System surface area, to collect the same equivalent energy, as a Solar Thermal System.

Three-Collector Solar Thermal Drainback System, Town-of-Newburgh, Orange County, NYThree-Collector Solar Thermal Drainback System, Town-of-Newburgh, Orange County, NYOther considerations include: PV systems cost considerably more than solar thermal systems, so you would need significantly more capital, to make such an improvement to your home or business. 

Larger Solar Thermal Systems require more space for energy storage (typically stored in larger or multiple water tanks or can be deposited directly into concrete slabs via radiant heating system).

At APEX Thermal Services, we are here to assist you in achieving your energy-efficiency and solar energy goals.  Visit the Contact Us page to drop us an email and let us know what you are thinking!