Solar Panels - Solar Hot Water

SOLAR HOT WATER - SOLAR THERMAL

Solar water heating (known as solar thermal) captures heat from the sun and uses it to heat up water for use in the home. panels on your roof absorb heat from the sun the water in the panels heats up this hot water is pumped through a coil in your cylinder
which transfers the heat to the water in the cylinder.

Is solar thermal suitable for my home?

• Optimum position of solar panels is facing due south
• Although they are effective facing anywhere between south east and south west.
• Typically best performance is at an angle between 20 and 50 degrees from horizontal (most pitched roofs fall within this bracket).
• Solar panels are compatible with most existing hot water systems. 
  
• Solar hot water with combi boilers is more difficult, but still possible.
  
• If you have a combi boiler it is important to check with the manufacturer that it will accept pre-heated water.

The Energy Savings Trust says solar panels will ‘provide about a third of your hot water needs’.

Renewable heat incentive
The proposed renewable heat incentive (RHI) aims that 12% of heat is generated renewably by 2020.

How it works
The domestic renewable heat scheme will not be introduced until October 2012, to coincide with the Green Deal. Eligible heat systems installed since 15 July 2009 will be entitled to claim.

• In the interim, the government has allocated £15m for an RHI Premium Payment on up to 25,000 domestic installations.
  
• Rates will be confirmed in the summer 2011, but they are expected to be as follows:
• Solar Thermal - £300/unit
• The premium payment scheme will start in July 2011.
• To qualify for the payments you will need a "well insulated house based on its energy performance certificate

The government will consult on the domestic tariffs for the renewable heat incentive later in 2011. Using rates set for the commercial phase of the RHI as a guide, the tariff from the original consulation launched by the previous Labour government in July 2009 rates for solar thermal are 18p per kWh for 20 years

Two types of solar hot water panel

Flat plate panels

• Consist of an absorber plate in an insulated metal box.
• The top of the box is glass or plastic, to let the sun’s energy through.
• The insulation minimises heat loss.
  
• Lots of thin tubes carry water through the absorber plate heating it up as it passes through.

Evacuated tube

• Collectors have glass tubes containing metal absorber tubes, through which water is pumped.
• Each tube is a vacuum which minimises heat loss.  

What does solar thermal cost?

• Heating water accounts for 17 per cent of energy use in the UK and for 20 per cent of domestic carbon emissions.
• To maximise benefit, a system should be capable of producing around 50 to 70 per cent of all water heating that is not associated with space heating.
• Solar thermal is eligible for the renewable heat incentive.
• To qualify you must use a MCS accredited installer and product.