Wednesday, February 1, 2017: 11:00 AM-12:30 PM
Fundamentals and Applications
Chair:
Wangda Zuo, Ph.D., University of Miami
Technical Committee: 7.4 Exergy Analysis for Sustainable Buildings (EXER)
Achieving low energy buildings requires optimal usage of energy in different forms, which can be predicted by exergy modeling. This seminar invites experts to introduce how to perform exergy modeling for evaluating different energy systems such as a PV system and a hybrid heating system. The experts will also elaborate the difference between energy modeling and exergy modeling to highlight the unique information obtained from exergy modeling.
1 A Simplified Exergy Methodology for Net-Zero Buildings Using Rational Exergy Management Model
This study discusses the importance of exergy balance rather than energy balance of a net-zero building with the built environment involving such district connections like heat, cold, service water etc. and presents a simplified degree-hour method and Rational Exergy Management model that enables to calculate the net-exergy feature of any sustainable building in term of exergy exchange between the district and the building.
2 An Exergo-Parametric Study of Hybrid Heating Systems
In this study, an experimental data based exergo-parametric study of hybrid heating systems is carried out. Experiments are conducted in a special test chamber that was constructed and operated according to ANSI/ASHRAE Standard 138. Radiant floor heating and convective heating combinations at different splits were investigated for minimum exergy destruction and energy consumption while thermal comfort was maintained. According to the results, optimal radiant system to total system capacity ratio is about 0.6.
3 Energy and Exergy Analysis of Water and Air Cooled PVT Systems with Heat Pipe Technology
The aim of this study is to design a PV panel cooler with heat pipes and to reduce the pumping costs through an optimum design approach using CFD(Computational Fluid Dynamics) techniques. According to CFD analyses, up to 12% of the original power generation capacity can be achieved by the new heat pipe technology. This paper also compares air cooling by finned heat pipes using natural convection and chimney effect. These results however show that technically feasible option is cooling by heat pipes and by generating useful heat if there exists a demand of suitable magnitude and load profile.
4 Application of Exergy Principles in the Design and Analysis of Heating and Cooling Systems in Buildings
Exergy analysis, in addition to energy analysis, enables to study the effects of different operating temperatures on overall system performance. Exergy analysis also enables to compare different forms of energy flows (e.g. electricity vs. thermal) and, therefore, allows a holistic approach to system analysis. This talk outlines the main principles of exergy analysis, shows its applications in the analysis of heating and cooling systems in buildings, and presents results from the comparison of different heating and cooling systems using exergy. Exergy analysis is a powerful tool for improving and optimizing overall system performance.