Solar Thermal FAQ's

What is Thermal Solar?

Solar collectors are either evacuated tubes or flat plates and are used to absorb the suns electromagnetic energy. By the use of non -selective surfaces within the collector 90 to 95% of the energy is absorbed and the heat is transferred to a transfer fluid that flows within the plate.

Evacuated tubes work in a slightly different way, the heat absorption causes a special heat fluid contained within the heat pipe to boil and transfer large amounts of heat. As this vapour rises within the heat pipe it enters a condenser zone within the collector manifold, this is where the heat transfer takes place from the heat pipe to the transfer fluid.

Uses of Thermal Solar

Thermal solar can supply up 70 % of the household domestic hot water needs. It can also be used for space heating and swimming pool heating. A standard system for a 3 bedroom house would consist of 2 panels and a twin coil cylinder together with the associated hardware to integrate the parts. For larger householders larger cylinders and more panels are required, we will advise you during our site assessment.

Solar insolation

This is the amount of electromagnetic energy (solar radiation) incident on the surface of the earth. Basically, it is how much sunlight is shining down on us.

By knowing how much energy we have we can calculate collector sizes to match the energy demands for each application. Insolation is expressed in Kwh/m2/day; this is the amount of energy that strikes a square metre of the earth's surface in a single day, or equivalent sunshine hour (ESH).

1KWh/m2/day = 317.1 btu/ft2/day = 3.6MJ/m2/day

The greater the light intensity falling on the collector the hotter the heat transfer will be. So with an insolation level of 1000W/m2 on an average 2 panel system covering 4m2 of roof area the energy generated will be 3.8KW per hour under peak conditions.

A typical house uses about 5KWh per day of useful energy for domestic hot water so you can quickly see how thermal solar systems can meet your DHW needs.

Suppose there is not enough sun.

In winter months the sun's angle in the sky is low therefore the insolation level drops as does the level of heat transfer from the collector. This is when your primary heating system will be required as a back-up to the solar system.

System Design

New Generation Energy will design a solar system that is best suited to your application and needs, we only use quality parts from respected manufacturers that will provide you with a system that will work for years to come.

Planning permission is not generally required unless you have a listed property or live in an area of outstanding natural beauty, AONB although we would recommend that you speak with your local planning authority prior to starting work. We can help you with this should you wish.

In general we specify a hot water storage capacity of 50 litres per m2 of collector area. And for calculation purposes we assume a use of 40-45 litres of hot water per person per day.