Abstract - "Exergy analysis as building retrofit strategies assessment" - KEP energy

The energy and environmental impacts due to the energy consumption in the building sector are one of the main topic towards which is addressed the global action in the energy field. A building is an energy system that uses energy sources in order to maintain its functionality and to ensure thermal indoor comfort for the occupants. The exergy analysis is a way to assess the impact of an energy system on the environment.

The paper introduces a model able to describe the interaction between a building and its surrounding from an exergetic point of view. The building is considered as a “Black Box”, evaluating the exergy of overall energy and matter fluxes that cross the system boundaries. In this way it is possible to evaluate the exergy balance of the system and particularly the destroyed exergy. The exergy destruction percent can be understood as a building environmental impact indicator.

In order to illustrate the model, and its operating suitability, an existing building has been analyzed through the transient simulation software Trnsys. The modeling results show that about 95% of the exergy used from the building is destroyed and that about 5% is loss (transferred to the surrounding). This means that this building has very high impact.

The model can be applied to the effectiveness assessment of different building energy retrofit strategies. Through the Trnsys modeling have been analyzed some conventional and advanced retrofit strategies, as well on-site renewable energy utilization. The paper presents the main analysis outcomes, showing which of these strategies are able to reduce the building exergy demand, and so the building impact.

L'articolo completo è pubblicato in "Mediterranean Green Buildings & Renewable Energy", Springer International Publishing, 2017.