Solar Energy - How it Works

Solar Panels, can they be used in the UK?

Yes � Solar works from light, so as long as there is light a solar panel will be generating energy � it will of course produce more energy on a clear day when light is not being broken by clouds.

Systems will vary in the UK from those used closer to the equator and prices will vary also. The main difference is the amount of surface area required every system will have a different efficiency rating and this too will effect how many panels you will need.

Will it work when the Sun isn't shining?

Solar panels can produce electricity whether its is cloudy or sunny just not at night. However, the more sunlight there is, the more electricity a solar panel can produce. The length of day will also effect how much electricity a solar panel can produce, meaning that Summer months with longer days are a better time for charging the all important MP3 player.

What is Solar Power?

Solar can be used for a number of different applications but the two main categories are:-

  • Producing Electricity � Photovoltaic Solar Panels (PV)
  • Producing Hot Water � Solar Panel Collectors

PV Solar Panels

PV solar panels produce environmentally clean, safe electricity in the form of Direct Current (DC) electricity similar to that released by batteries. In fact most solar powered equipment uses a battery and the solar panels are simply there as a battery charger, exploding the myth that solar powered torches do not work in the dark. This means that solar panels can be used to power battery chargers, lights, mobile phones, radios, torches, everything and anything that requires electricity. PV Solar panels have no moving parts, and are therefore, silent and reliable.

PV Home Systems are also available but are not common place due to there high cost and long payback period.

Solar Collectors

Solar Collectors however are used for home hot water systems as they are cost effective when savings and pay back periods are taken into account. Solar collectors come in two main forms � Evacuated Tubes or Flat Panel Collectors.

Which is Better: Evacuated Tubes or Flat Panel Collectors?

Each installation needs to be looked at individually however usually the flat plates have more merit. It's all about the 'aperture area or absorber surface' which is the part of the collector that collects light and turns it into heat. It is common myth that flat panel collectors do not work on cloudy days however all solar panels will work as long as there is light.

If you compare flat plates and evacuated tubes by metres squared of aperture area vacuum tubes are more efficient than the flat plates, but if you look at costs per solar panel, collector or system you typically have a much larger absorber surface area on a flat plate system so for a similar cost you would normally expect more output from the flat plates.

Orientation of flat plate collectors isn't a problem and vacuum tubes have no benefit over flat plates except on an east facing or west facing elevation where vacuum tubes would be more desirable.

As a general rule you would expect a 3m2 vacuum tube system to have a similar output to 5m2 flat plate system.

How Do Photovoltaic Solar Panels Work

The Photovoltaic effect discovered in 1839 by 19yr old Edmund Becquerel, is the phenomenon that certain materials produce electric current when they are exposed to light.

How does it work?

The Sun produces a range of energy which we can only see a small part of as visible white light. Solar panels turn another part, or wavelength, of the light into electricity that can be harnessed. A photovoltaic cell (PV Cell) produces electricity on the principle that electricity will be produced when two semiconductors are exposed to a particular wavelength of light. Groups of PV Cells are linked together to form panels, the bigger the panel and the more cells, the greater the amount of electricity can be produced.

Photovoltaic Solar Panels in the Home?

PV Solar Panels are connected in parallel with the existing electricity supply. Your electricity is primarily supplied by the solar but should they not be able to provide (at Night) then your normal supply will be used. If an over supply is being generated then this will get sold back to the grid.

Solar Home - How Much Does It Cost?

Hot water Heating Systems.

Prices do vary based on a number of factors but most professional installation companies will come to your home and give you a free no obligation survey. Register here for your free survey.

Flat panel Collectors can be purchased from DIY stores from as little as �1,500 per panel however what they neglect to mention is that you will require a twin coil cylinder and it is very unlikely that you will have one already!

A High Quality Stainless Steel twin coil cylinder will cost around �700. You will also require a Pump, a temperature management control unit and all the copper piping and fittings to plumb the system in. Oh and don't forget the labour costs, it really is not a job I would recommend you do yourself.

All prices are approximate based on an average installation

  • Panel x 2 = �3,000
  • Cylinder = �700
  • Pump = �800
  • Control Unit = �200
  • Copper pipes = �200
  • Copper Fittings = �100
  • Labour = �1,000

TOTAL = �6,000

Factors that may increase this price are:-

  • East/West roof � additional plumbing and equipment required
  • Combi Boiler � you will have to have additional plumbing work carried out
  • Large House � More Panels and larger tank required
  • Small house � Less Panels and smaller tank required