In the ’70s and early ’80s, solar power was thought to be the panacea for the world’s energy crunch and would become a major source for heating for homes and industry. However, due to the fact that most of the solar collectors were the “flat-plate” type and the method of heat transfer was less than adequate, most solar collectors fell by the wayside.
Due to the high cost of fuel and urgent concerns for the environment, some European countries developed advanced solar technologies.
Some solar collectors are designed to operate in temperatures from -50°F to 250°F — it also will work in all weather conditions.
Since the unit takes advantage of direct and indirect radiation, the collector does not need direct sunlight to work. Even on cloudy, cold or foggy days, the unit will continue to supply heat energy.
The secret of the efficiency of the unit and the fact that direct sunlight is not required is that the absorber plate is hermetically sealed inside a glass vacuum tube.
It has a series of glass tubes connected to a well-insulated manifold. A special low-iron glass is used for the tubes with a wall thickness of 1.6 millimetres.
Light and radiation through the body of the glass is excellent. The copper plate absorber has a special “selective surface coating.”
The heat pipe, being a super efficient conductor and having very low heat capacity, quickly transfer heat energy to the heat exchanger outside the tube. The vacuum eliminates heat loss from the collector due to conduction and convection. During the manufacturing process, air is evacuated from the glass tube much the same as it is from a television picture tube, producing and extremely low level of vacuum. The sealing of the glass to metal incorporates a special patented thermal shock absorber.
Absorbents are used in the tube to absorb any out-gassing from internal parts thus maintaining excellent vacuums.
The transfer medium is an alcohol mixture. There is nothing in the collector to freeze. Special controls limit the temperature in the pipe to prevent the liquid from boiling. The heat transfer medium is pumped through a closed loop system.
The manifold that collects the transfer medium from the vacuum tubes has a minimum liquid capacity. It is made from “marine quality” stainless steel and is sealed in a weather-resistant metal cover. The space between the manifold and the cover is insulated with thick polyurethane foam insulation.
It is manufactured in two sizes, 20 tubes or 30 tubes. They are light and easy to install. The system design is flexible due to the modular concept.
Usually, the collector is mounted on the roof and does not require and additional support. No maintenance is required.
Dust or debris is carried away by wind and rain from the round, smooth glass tubes. There are no moving parts to wear out.
The medium in the collector transfers heat-to-heat water in the home and is capable of producing 100 per cent of your hot water requirements on an annual basis.
A lower cost unit can produce 100 per cent of your hot water needs in the summer and a good percentage during the winter. It also provides the heat needed for a home hot water in-floor or in-slab heating system. Water can be heated for pools, spas, and hot tubs.
Commercial applications are endless.
Remember that sunshine is non-polluting, non-taxable and, above all, free!
So, investigate solar heating for your home and do yourself and the earth a favour.