A correctional institution in Tehachapi, California, uses solar energy to supplement the existing boiler system to provide hot water and space heating for 5100 people. This privately owned system provides energy at a cost below the commercial rate for natural gas heating. Engineers based their design of the system, built in 1990, on the available sunshine, the efficiency of the existing boiler system, the effectiveness of the collector troughs in tracking the sun and concentrating its rays on the tubes carrying collector fluid, the efficiency of the heat exchanger, and the system reliability. All this information was vital not only to the design of the system but also to its evaluation, its operation, and even to the decision to go ahead and build the system.
Accurate information is important for designing energy systems.
It explains what solar radiation data are, why they are needed, what data are measured, how the data are used, and how data uncertainties affect performance and economic projections.