Thermoeconomic Approach to the Diagnosis of A DHW

Microcogeneration Plant

Ana Picallo-Perez1, Perez-Iribarren E.1, Apaolaza A.2, and Sala J. M.1

1. Research Group ENEDI, Department of Thermal Engineering, University of the Basque Country (UPV/EHU), Spain

2. Laboratory for the Quality Control of Buildings, c/Agirrelanda nº10 Vitoria-Gasteiz

Abstract: Application of Thermoeconomic in the diagnosis of power plants allows the localization and quantification of an abnormal operation, which can cause significant increase in consumption or even unacceptable shutdowns. Accordingly, the early detection of these anomalies may prevent possible failures and make savings in both maintenance and energy consumption. 

 Thermoeconomics has not been widely used in the field of thermal installations in buildings, even less its diagnosis application. This communication contains the results of the implementation of Thermoeconomics diagnosis in a micro-cogeneration facility for DHW, consisting of a microcogeneration engine, a condensing boiler and an accumulation tank.

  To assess the malfunctions and dysfunctions in a facility in which demand varies over time, virtual testing analysis path has been chosen. This is done through a dynamic simulation software of buildings (Trnsys). For this purpose, a common reference state and various operating conditions have been defined. These operation modes include different types of disturbances; first anomalies are introduced one by one and then several of them are analyzed simultaneously.

  Once the productive structure of the system has been determined in its FPR representation, a thermoeconomic study for a specific situation has been performed. This analysis enables the obtainment, among other results, of the exergetic unit cost of the fuel, waste and product of each subgroup. Regarding the reference installation as the comparative base, the endogenous and exogenous effects a malfunction creates along the entire energy chain have been investigated. For the anomaly case, an analysis of the results has been elaborated and conclusions have been obtained.

Key words: Thermoeconomic diagnosis, FPR representation, malfunction and dysfunction