Economic evaluation of solar energy systems in commercial buildings :

Abstract

This report develops a comprehensive economic optimization model for evaluating the economic feasibility of active solar energy systems to provide service hot water and combined space heating/service hot water in commercial buildings. The model is demonstrated in a number of case studies for office buildings and retail stores. Data and assumptions for use in the model are compiled for the selected case studies. Using these data, the model is applied to estimate present value net savings (or net losses) of the solar energy systems over a 20-year life cycle. Break-even values for hot water loads, solar energy system costs, and current and future energy prices are also calculated to determine the minimum conditions under which the solar energy systems become cost effective for the selected buildings. Economic optimization paths which show the optimal solar collector areas and the corresponding present value of net savings (or net losses) associated with a range of hot water loads are developed in the case studies. Sensitivity analysis is conducted for key variables. The relationship between total life-cycle costs and the solar fraction is tested for selected cities to demonstrate how net savings (net losses) change as the solar fraction is increased.

Benefit-cost model of residential fire sprinkler systems

“…•'•For a general reference to benefit-cost analysis, see E. J. Mishan, Cost-Benefit Analysis , New York: Praeger, 1982. For a further description of life-cycle costing, see Rosalie Ruegg and Harold Marshall, "Economics Standards, NBSIR 82-2558, July 1982 costs from discounted benefits, the net benefits (or net losses) measured in either present value or annual value dollars can be determined. By dividing discounted benefits by discounted costs, a benefit-cost ratio can be calculated.…”