A typical domestic system will produce around 65 to 75% of a UK households annual Domestic Hot Water requirements. In the summer months it will produce 100% of your needs, whilst in the depths of winter it will only produce around 10% of your requirements. The following chart shows an average for a UK household with a correctly sized system:
A system should be sized so as to provide 100% of DHW requirements during the summer months. Adding extra panels to cope with the winter months would not make sense as during the summer months the excess heat generated would be “dumped” as it would be surplus to requirements. Also the system would also be oversized and therefore running below optimal efficiency for the majority of the year (the excess heat generated during the summer months could also damage the system).
As a general rule, Flat Plate collectors are approximately 40% efficient, meaning a 1 meter squared collector in the UK (which receives 1,000kWh/m2 per annum of solar radiation) will generate approximately 400kWh of energy. Similarly an Evacuated Tube collector is approximately 50% efficient and therefore will produce 500kWh of energy. The loss in efficiency can be split as follows:
Here you can see the importance of insulating pipes and the hot water tank as combined losses through conduction lead to a total loss of efficiency of some 15%!
Home Pages of interest:
- Visit the Solar Thermal home page
- Visit the Energie Solar home page
- Visit the Solar Thermal and Swimming Pools home page
Other Pages of interest in this section:
- What is Solar Heat Power?
- How Does Solar Thermal Work?
- Types of Solar Thermal Systems
- Flat Plate versus Evacuated Tube Collectors
- Annual Energy Production
- Components of a Solar Thermal System
- Costs of a Solar Thermal System
- Servicing and Warranty
- Solar Thermal Financials and Paybacks
- Our Products
- Solar Thermal and Swimming Pools
