Energy resource requirements of a solar heating system

The methods of energy analysis have been applied to a liquid-based, short-term storage solar space and water heating system suitable for a single family dwelling in Toronto. This system, which in many respects represents a worst case for solar heating, takes 1.0–3.5 years of operation to conserve the energy resources required to build, operate and maintain the system. Alternatively, over the twenty year lifetime of the system, the energy resources used indirectly by the solar heating system amount to between 6 and 24% of the direct energy resources conserved by the system. These considerations do not significantly alter the energy-conservation characteristics of the solar heating system unless thermally-generated electricity is used as backup for a 50% solar heating system which replaces oil or gas heating; in this case, only 4–9% of the energy resources are conserved by the solar system. A factor of three variation in energy resource use in collector materials was found in a sample of 7 flat-plate collectors with steel-based collectors using the least. The total energy embodied in the collector was about double that found in the materials alone. The collectors and annual operating energy for the pumps were found to be the two most significant factors in the analysis. An appendix summarizes the energy resource requirements embodied in the materials used for collectors.