How Does Solar Heating Work

Solar thermal panels are a lot more efficient at solar heating water than photovoltaic panels!

Solar thermal panels are used for heating hot water which in turn can be used to heat your house, water for washing and showering and is a very green way of heating your swimming pool.

Most solar heating systems are used to heat water for washing and showering. The way the system is typically designed and installed is to have an array of solar collector panels on the roof of your home. These are then connected to a hot water tank and a fluid is circulated around the solar panels and the hot water tank. As the fluid passes through the panels, the suns energy heats the fluid up to a high temperature. However, the fluid that is circulated through your solar panels is used to heat the water in your hot water tank, it is not used for washing and showering.

These are not passive systems. They will have sensors to detect when the sun is hot enough to heat the fluid and will then start the pump working.

How Does the Fluid Heat the Water in the Hot Water Tank?

Inside your hot water tank is a copper pipe which is made into a coil so that you get a greater surface area in which to transfer the heated fluid in the copper pipe to the water stored in the tank.

This coiled copper pipe has an inlet at the bottom of the tank and an out let at the top. The solar panel outlet pipe is connected to the inlet on the tank and the outlet pipe of the tank is connected to the inlet of the solar panel.

What If the Solar Panel Does Not Generate Enough Hot Water?

If the solar panels, be it flat plate or evacuated tube type, do not heat the water to the desired temperature then you have a back-up system. You can get hot water tanks that are fitted with an electric heater element and a thermostat. Therefore the thermostat can detect if the water is hot enough, if it isn’t, the electric element will switch itself on until the correct temperature is reached.

Alternatively you can have your boiler plumbed into your hot water tank. This could be a back boiler which is fitted to a log burning or coal fire or it could be a gas boiler. So if the water is not hot enough, either of these systems will cut in as necessary.

If you have any questions about how solar heating works then ask it in the comment section below.


5 Comments on How Does Solar Heating Work

  1. Matt@Industrial Heating Elements on Thu, 23rd Dec 2010 3:40 pm
  2. You do not essentially require a ton of overpriced gizmos to comprehend the main advantages of passive solar heating systems. Passive heating gathers and guides heat without the help of virtually any mechanical or electric powered equipment .

  3. pj bonner on Thu, 3rd Feb 2011 3:07 pm
  4. if you use your solar panels to create solar heating can you not use the same copper tank for domestic hot water

  5. Carlton on Thu, 14th Apr 2011 11:59 pm
  6. I have an 80 gal tank with 2 panels that measure 64 sq ft. I believe I have too much panels because the relief valve on the panel discharges once in a while. Can you advice me how to decrease (cover) the panel to reduce surface size? If this is not my problem please comment.

    Thank you.
    PS I live in Hawaii – lots of sun.

  7. sandra avery on Tue, 7th Jun 2011 7:52 pm
  8. how effective is solar panels on the roof of an older house in nh. if we do not get much or enough sun to heat the system in the winter then how efficent is it if we need back up heaters for the water…seems it would be defeating the purpose because I would have to use either electric or gas to heat the water or fluid more then enough to heat my house… what do you advice. would staying with my gas furance be just as genergy efficent…with a new furance instead of solar panels

  9. Pete Hamil on Mon, 19th Sep 2011 1:44 pm
  10. Is it possible to satisfy heating, domestic hot water and snow melt, giving prority to domestic hot water and space heating from 3-80 gals solar hot water storage tanks with dual coils.I want to use 4-30 evacuated tube panels. will I need a seperate heat exchanger for the snow melt and what type of controls will I need to seperate glycol in solar panels from mixing with domestic water.

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