An exergy-based modelling tool for retrofit analysis in non-domestic buildings

By Ivan Garcia Kerdan

Supervisors:

Paul Ruyssevelt

Rokia Raslan

2012 to 2016

Approximately half of the energy used in the UK is dedicated to space conditioning and water heating purposes, where buildings are responsible for 52% of the overall energy used. Since indoor temperatures usually range between 18-25 °C, research indicates that the heating needs of buildings can be met by low-grade heat sources.  

However, a key issue associated with this application is that of the ineffective match between the potential of the sources and the demand of the buildings resulting in thermodynamic efficiencies lower than 10%. Consequently, it can be suggested that exergy analysis (a combination of first and second law of thermodynamics) can become essential in locating the aforementioned inefficiencies and seeking opportunities for improvement.  For this reason, building energy retrofits with the support of exergy analysis should be encouraged to reduce energy utilisation, exergy destructions, and carbon emissions in the building sector.  

The aim of this research is to develop an understanding on how simulation tools based on exergetic analysis and thermoeconomics methods can help to optimize current building systems and their energy supply chain, and provide a more accurate energy description of the building before and after retrofit actions are implemented. The research will focus to answer the next questions: 

a)  What is the potential of using exergy analysis for retrofit decisions in non-domestic buildings?

b) What is the potential of using exergetic dynamic simulation tools as a means of finding inefficiencies in non-domestic buildings and their energy supply chain?

c) What are the impacts of different scenarios of refurbishment on energy and exergy consumption and what is the margin for exergy saving within the current UK non-domestic buildings and their energy supply chain?

d) What are the strengths and limitations in decision-making of using a thermoeconomic evaluation approach for building energy retrofits?