Solar heating and cooling of buildings (SHACOB): requirements definition and impact analysis. [Impact on electric utilities]

The installation of Solar Heating and Cooling of Building (SHACOB) systems usually requires a backup system--often electric--to take some portion of the load on days of low insolation, and to carry the entire load during extended periods of low insolation. The implications of such systems on the economic operation of electric utilities may be significant if a displacement of required generating capacity does not accompany the displacement of energy. The objective of this study was to assess the economic impact of various SHACOB design concepts on the electric utilities and their customers and to define system requirements for optimizing this impact. Weather and insolation inputs for simulations were established for locations across the United States. Reference buildings and their thermal properties were defined according to ASHRAE 90-75 standards, and detailed internal and external load models generated to characterize building thermal performance. The TRNSYS program was modified to simulate the performance of both solar and conventional systems, including load management systems featuring nighttime thermal storage. The systems analyzed in detail were direct solar systems with and without a load management capability, solar assisted heat pumps, and customer load management systems. These systems were evaluated with respect to conventional resistive and heat pump systems. Projections for new buildings and types of heating system installations in those buildings were developed by eight participating utilities for their own service areas. TRNSYS simulations for the various types of systems in a wide variety of building types were used to generate backup electric demand time histories for representative cities in or adjacent to the eight service areas.