Three variations of a basic solar collector system are presented in this article. All incorporate heat absorbing commercial built 'Solfin Panels' from Thermo Dynamics Ltd., and all have insulated heat storage water tanks. The pros and cons of each configuration are described to help readers understand how different arrangements may affect performance.

The Original System

The original system was constructed in 1982 and consisted of 3 thirty gallon tanks connected in series to an electric hot water tank. The tanks were mounted in the upper portion of the solar sunspace. Even when the sun wasn't shining, the water in the tanks absorbed heat from the surrounding air. When a hot water tap in the house was turned on, the replacement water going into the electric tank would be the water prewarmed in the three storage tanks. The water in the tanks would heat to around 50¡ C in the sunshine. No pump was necessary as the pressure in the lines carried the water through the system. The main disadvantage of this system was that it did not provide a means of insulating the tanks.

System 1

System 1 uses a dedicated window area in a sunspace storage room. Two Solfin panels (4' x 8') are placed immediately inside the windows. The system is connected in series with a 60 gallon storage tank sitting at a higher elevation than the electric hot water tank. The storage tank feeds directly into the electric tank.

System 2

In System 2, two (4' x 8') Solfin panels are mounted at an angle in a sunspace. A 60 gallon super insulated storage tank is placed in an attic space above the panels. Valving systems are used to feed the solar hot water to the electric tank or to allow the solar hot water to be used directly as domestic hot water. System 2 is very efficient. It supplies all hot water needs for six months of the year and a high proportion of the rest of the year. Solar hot water can easily be augmented by wood stove heated hot water.

System 3

System 3 would be appropriate for summer cottage use only. It uses one 4' x 8' Solfin panel feeding a 40 gallon electric hot water tank located on the second floor. The solar panel is mounted at an angle outside of the cottage. One panel can provide 98% of most cottage hot water needs. Power to the heating coil can be turned on any time to maintain the temperature of the heated water. The unit must be drained for the winter. This configuration of system has been known to reach boiling temperature.

Benefits of Natural Thermo-Convection

All systems work on the principle of natural thermo-convection, i.e., that hot water rises. There is no need for glycol in the systems because the entire system is either inside heated areas or only for use during the frost-free period. No moving parts are required and little or no maintenance is needed. You can even install an outside hot water tap for washing cars.