Technical and Economic Assessment Of Solar Thermal Absorption Cooling Systems in Small Commercial Buildings

ABSTRACT

This article presents the results of an initial assessment of the technical and economic feasibility of supplemental solar thermal absorption cooling systems for small commercial and institutional buildings in the Southwestern United States. Solar thermal absorption cooling systems use chillers powered by solar energy rather than natural gas or electricity. The following factors may position solar thermal absorption cooling systems as a competitive alternative to conventional electric or naturalgas-driven air conditioning:

	Recent technology advances have occurred in concentrating solar thermal direct flow vacuum tube-type collectors.
	The Energy Policy Act of 2005 includes a non-capped 30% investment tax credit for solar thermal cooling systems on commercial buildings.
	Natural gas retail prices are near record highs, increasing peak electricity rates.
	Use of renewable energy powered cooling systems can lead to lower electric demand and reduced power plant emissions.

Initial assessment results show that solar thermal cooling systems are feasible in areas with a confluence of high solar insolation, high cooling demand, and high electric rates, achieving payback of less than 8 years in typical five-story buildings. In smaller commercial and institutional buildings, solar thermal absorption cooling system life-cycle costs are also favorable in comparison to conventional cooling systems.