Economic analysis of exergy efficiency based control strategy for geothermal district heating system

Abstract

In this study, the exergy efficiency based control strategy (ExEBCS) for exergy efficiency maximization in geothermal district heating systems (GDHSs) is economically evaluated. As a real case study, the Afyon GDHS in the city of Afyonkarahisar/Turkey is considered. Its actual thermal data as of average weekly data are collected in heating seasons during the period 2006-2010 for artificial neural network (ANN) modeling. The ANN modeling of the Afyon GDHS is used as a test system to demonstrate the effectiveness and economic impact of the ExEBCS under various operating conditions. Then, the ExEBCS is evaluated economically in case of application to real Afyon GDHS of the ExEBCS. The results show that the initial cost for the ExEBCS is more expensive than that for the old one by 6.33 kUS$/year as a result of replacing automatic controller. The saving in heat production makes the ExEBCS profitable by up to 7% of annual energy saving as a result of the increase in the heat production by 88% when the control system is operated. This results in a short payback period of 3.8 years. This study confirms that the use of ExEBCS in district heating systems (especially GDHS) is quite suitable. (C) 2013 Elsevier Ltd. All rights reserved.