Solar Thermal - Panels and Equipment

Flat plate collectors

Flat plate collectors, developed by Hottel and Whillier in the 1950s, are the most common type. They consist of (1) a dark flat-plate absorber of solar energy, (2) a transparent cover that allows solar energy to pass through but reduces heat losses, (3) a heat-transport fluid (air, antifreeze or water) to remove heat from the absorber, and (4) a heat insulating backing. The absorber consists of a thin absorber sheet (of thermally stable polymers, aluminum, steel or copper to which a matte black or selective coating is applied) often backed by a grid or coil of fluid tubing placed in an insulated casing with a glass or polycarbonate cover. In water heat panels, fluid is usually circulated through tubing to transfer heat from the absorber to an insulated water tank.

Evacuated tube collectors

Most (if not all) vacuum tube collectors use heat pipes for their core instead of passing liquid directly through them. Evacuated heat pipe tubes are composed of multiple evacuated glass tubes each containing an absorber plate fused to a Heat pipe. The heat from the hot end of the heat pipes is transferred to the transfer fluid (water or an antifreeze mix—typically propylene glycol). The vacuum that surrounds the outside of the tube greatly reduces convection and conduction heat loss to the outside, therefore possibly achieving greater efficiency than flat-plate collectors, especially in colder conditions.

Pump Stations

Pumping stations are used for the circulation of Glycol mixed fluids through solar thermal heating applications and provide:

  • Filling & flushing connection points
  • Fluid flow regulation
  • System temperature & pressure readings
  • Check valve for anti-gravitation
  • Safety relief valve & discharge connection
  • Point of connection for expansion vessel & isolation

Solar Cylinders

Twin coil andtriple coil solar cylinders are specifically designed to work in conjunction with the domestic heating system. The coils are designed to transfer heat from an independent heating source, (eg. transferring heat from the solar collectors and a central heating boiler to the water in the cylinder). These are available in various sizes and designs, Vented and Unvented.