Energy Saving with Absorption Equipment: a Case Study

Abstract

The paper deals with the results of a feasibility study performed at DREAM which is related to the possibility of using reject heat from an Electric Utility (which has a Combined Cycle Unit with Gas and Steam turbines belonging with ENEL Pro. at Termini Imerese, Palermo). The Utility lies near an Industrial District where there has need for feeding a Cooling Plant for Foodstuff Stocking at two different temperature levels: 0 °C and -18°C. The feasibility study covers both technical feasibility of a suitable cooling plant which use two separate absorption equipment, working with the pair Ammonia-Water, and economic feasibility of the venture. The feasibility study pertains: to the optimal design of the Absorption Equipment that will be built on commission, to the energetic and exergetic analysis of each part of the plant and, also, the same kind of analysis was made for a reference case pertaining a Two Stage Reciprocating Compression Refrigerating Plant. Moreover was performed an economic analysis making a comparison between the venture, whose feasibility is investigated, and reference case. Investment costs considered in the analysis are differential costs between the option considered and that of reference case. The analysis demonstrated that expected time of return on differential investment is of four year and the specific investment costs expected, considering differential costs between the two alternative options, are: 1.12 c€/toe of primary energy saving and 0.9 c€/t(CP 2,eq) of lower emission of greenhouse gases.