What’s Solar?
The term solar power is used to describe methods of harnessing energy from the sun. As environmental concerns, such as greenhouse gases and the depletion of fossil fuels increase, renewable – energy resources, such as solar power are becoming ever more popular in the UK and across the rest of the world.energy source,solar power,solar energy,uk,renewable energy resources,renewable energy,
In the UK we receive vast amounts of solar energy, with the average amount of energy received in a year being as much as 60% of that received on the equator. This radiation is similar to the output of 1,000 power stations.
Today there are a range of high quality products, which enable us to use the Sun’s energy very effectively in the UK. Using the Sun’s energy reduces our consumption of conventional fuel and helps to reduce the emission of harmful greenhouse gases.
The effectiveness and efficiency of solar energy in the UK is far greater than most people imagine. In the summer, when items such as black tarmac and car bodies are often too hot to touch we become aware of the Sun’s heat. However, even in the spring and autumn and on clear winter days we receive very useful amounts of solar energy. By tilting a surface to an angle the amount of solar radiation falling on it will be greater than that falling on a flat surface in this country.
Fortunately, the average tilt of a UK house roof is about the optimum for receiving solar energy in the UK.
The average property requires approximately 3,000 kWh per year for domestic water heating.
UK solar irradiation – annual total kWh/m2
This map shows the total average solar radiation falling on one square metre surface inclined at 30 degrees to the horizontal, measured in kilowatt hours.
These figures bring out the remarkable fact that the amount of solar energy falling on the total roof area of an average house is many times that required to provide all its heating and hot water. However, we must note that there is a large difference between the radiation available in the summer and that available in winter; also Active Solar Heating systems will typically convert 40 to 50% of the solar energy falling on the solar collectors into useful heated water. These factors must be taken into account in determining the optimum size for a system.
Would you be surprised if somebody told you that solar panels work effectively in temperatures of 0ºC and below?
It is a common misconception that solar systems convert the Sun’s heat into useable energy, this is simply not true. The panels are powered by Sun light; this doesn’t have to be direct sunlight! Even on a cloudy day you can rest assured that our system will produce enough energy for your hot water.
How Solar Heating Works
Solar water heating systems use solar panels, called collectors, fitted to your roof. These collect heat from the sun and use it to warm water which is stored in a hot water cylinder.
A boiler or immersion heater can then heat this water further until it reaches the temperature set by the cylinder’s thermostat. (This should be set at 60 degrees centigrade.)
Larger solar panels can also provide energy to heat your home as well – though usually only in the summer months when home heating is unnecessary.
The illustration shows a typical Active Solar Heating system layout. An electronic controller constantly compares the temperature of the solar collectors with the temperature of the water in the cylinder. Whenever the collectors are hotter than the cylinder, the controller switches on the system’s circulating pump. A mixture of antifreeze and water is then circulated through the collectors and the cylinder’s heat exchanger, heating the cylinder in just the same way as a central heating boiler.
Solar panels act like a mini power station on your roof. They collect Sun light which is absorbed by the panel’s specially engineered surface and convert it into heat. This heats up the heat transfer fluid in the copper heat transfer pipe to a temperature higher than the water temperature in your hot water cylinder. When a temperature greater than that in the hot what cylinder is achieved a digital controller activates a pump which pumps the heat transfer fluid through the heat transfer pipework in your hot water cylinder and heats up the water. When there is sufficient hot water in the hot water cylinder the pump stops. If the temperature in the hot water cylinder drops, or water is drawn off the pump starts again bringing the water temperature back up to the desired level. We fully expect our systems to provide up to 70% of your yearly hot water needs. We recognise that during the winter when days are short our systems will make a smaller contribution to your hot water than during the summer when days are longer, when our systems could provide you with up to 93% of your hot water needs.
The benefits of solar-powered hot water heating
• Hot water throughout the year: the system works all year round, though you’ll need to heat the water further with a boiler or immersion heater during the winter months.
• Cut your bills: sunlight is free, so once you’ve paid for the initial installation your hot water costs will be reduced.
• Cut your carbon footprint: solar hot water is a green, renewable heating system and doesn’t release any harmful carbon dioxide or other pollutants
Is a solar water heating system suitable for my home?
To tell if solar water heating is right for you, there are a few key questions to consider:
- Do you have a sunny place to put solar panels?
You’ll need 3-4 square metres of roof space which faces east to west through south and receives direct sunlight for the main part of the day. Alternatively, if you have space, you could install two panels, one facing east and one facing west – but this will make installation more complex and costly. - Do you have space for a larger, or an extra, hot water cylinder?
You will need this to allow room for a solar heating coil to warm your water. - Is your current boiler compatible with solar water heating?
Most conventional boiler and hot water cylinder systems are compatible with solar water heating. If your boiler is a combination boiler (combi) and you don’t currently have a hot water tank then a solar hot water system may not be compatible. - Do you need planning permission?
In England most solar water heating systems don’t need planning permission, but exceptions apply for Listed Buildings, and buildings in Conservation Areas and World Heritage Sites. If you live in Wales, Scotland or Northern Ireland you will need to consult your local authority.