Are evacuated tube collectors more expensive than Flat panel collectors?

Until recently Evacuated Glass Tube Solar Collectors were considered to be more expensive than the Flat Panel Collector, but now with modern production methods and economies of scale, the Evacuated Glass Tube Solar Collectors have now become more affordable.

What is the Secret of the Vacuum?

The secret of the Evacuated Glass Tube Solar Collector lies with the vacuum that surrounds the absorber. This vacuum allows light to pass through and be absorbed by the absorber surface where the absorbed light is converted to heat. Light will pass through a vacuum but heat cannot, so the heat that has been absorbed cannot escape back into the outside world by convection or conduction. Flat plate collectors loose a significant amount of collected heat to convection and conduction. In other words, when the winds are cold or it is raining, flat plates act like radiators and suffer from wind chill reducing the amount of heat harvested from the sun and are noticeably less efficient. The Evacuated Glass Tube Solar Panel, insulated by its inbuilt vacuum, does not suffer heat loss in this way.

Who will install the collector for me?

It is advised to use an SEI registered installer. SEI maintains a list of registered installers.

What type of pipe insulation should be used?

It is very important that the pipe insulation used can withstand the extremes of temperature that may occur in solar installations. High temperature pipe insulation should be used. Standard heating insulation could melt. On exposed external pipe work care should be taken to ensure the insulation is protected from the harmful effects of UV radiation. We have heard of insulation being robbed by resourceful birds, who obviously recognise the need for good home insulation! To guard against these we have found that if the insulation is covered with a good quality foil tape it is helpful with this problem.

The Thermo Store cylinder uses a 2kW backup electric heater. By using a solar collector and using the Thermo Store factory insulated cylinder we are reducing the amount of electricity we need. The addition of solar heat and increased levels of cylinder insulation will reduce your electric heating requirements, so a larger immersion is unnecessary. It is important to note that both the DBSi or DBSn controllers are rated to switch 2 kW. Please consult your electrician if the DBSi or DBSn controllers are to be used with other immersion heaters.

Optimally solar collectors should face directly south, but they can face up to 45 degrees east or west of south without a significant decrease in performance. If this orientation is not available, we can supply an east / west controller that will regulate which collector is used depending on which collector is receiving sunshine. So in other words any direction except north (except if you live in the southern hemisphere!)