How to Design a Small Solar Thermal Heating System

If your roof space is limited a small solar thermal heating system may be your only option. An evacuated tube collector has a better yield than flat plate.

Solar Thermal Evacuated Tubes

The most common restriction faced by most people wishing to fit a solar PV installation is the space available. Roof space, especially on older properties, was not intended to be used for solar panels and so fitting the installations is a matter of making the most of what the old designs allow.

Designing a small solar thermal heating system can be difficult where little roof space is available. But these points should help you to achieve the perfect small solar thermal heating system for your home.

How To Design A Small Solar Thermal System 400x245 How to Design a Small Solar Thermal Heating System

Designing the Best Small Solar Thermal Heating System:

To get the greatest solar gain from a small solar thermal heating system you will probably do best to use an evacuated tube collector. These have a higher yield per square metre than flat plate collectors.

This higher yield is due to the greater insulation created by the vacuum. Heat loss is almost totally avoided by containing the absorber within a vacuum . This also improves the yield in cold and low radiation conditions. This is because the absorber is not susceptible to the outside temperature.

Evacuated tube collectors achieve an output of around 600-650 kWh per squared metre per year. This is in comparison to approximately 500 kWh per metre squared per year for a flat plate panel.

However, as all solar panels are supplied in different shapes and sizes and you might find that flat plate panels will fill the roof space better than the evacuated tube panels available.

You can get some useful information on solar collectors from the SPF Swiss test facility. They have information on collectors, their sizes, and their outputs.

Where your roof space really is too limited, it is possible to install a small solar thermal heating system elsewhere. You should be able to find panels which can be mounted on A-frames, flat walls, or even pergolas located in the garden. You might also consider ground-mounted solar panels. These, however, are more susceptible to shading and collecting debris.

Image: SweEnergy

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