5. The inside of the tank is made of 1,2 mm thick stainless steel. Around the boiler is a 50mm PUR foam to keep the heat inside. On the outside you have a coated steel layer. In the tank are 2 copper heat exchangers. The bottom heat exchanger is connected to the solar collector and the upper heat exchanger is connected to the central heating system of the house for extra heating in the winter months.
7. At night the temperature of the water in the solar boiler drops because the insulation thickness of the boiler is only 5cm. To reduce the heat loss you can put an extra insulation layer around the boiler. The insulation is made of glass wool (fiberglass arranged into a texture similar to wool), covered with a layer aluminum foil.
8. Graph before extra insulation On the graph you can see that the temperature of the water at the top and at the bottom of the solar boiler drops around 10°. Depending on the temperature at night the heat loss can be higher or lower (between 5° and 15°). With the extra insulation layer the heat loss should halved (data found on forums).
