Literature review of topics relating to the exergy of PV. This is for a thesis comparing the exergy of equivalently sized PV farms and Coal Plants utilizing Carbon sequestration.
Reviewed literature[edit | edit source]
Optimizing limited solar roof access by exergy analysis of solar thermal, photovoltaic, and hybrid photovoltaic thermal systems[edit | edit source]
M.J.M. Pathaka,a, P.G. Sandersb, J.M. Pearceb,bc
a Department of Mechanical and Materials Engineering, Queen’s University, Kingston, ON, Canada
b Department of Materials Science and Engineering, Michigan Technological University, Houghton, MI, USA
c Department of Electrical & Computer Engineering, Michigan Technological University, Houghton, MI, USA
Received 16 April 2013, Revised 9 January 2014, Accepted 11 January 2014, Available online 14 February 2014
DOI: http://dx.doi.org/10.1016/j.apenergy.2014.01.041
Abstract
An exergy analysis was performed to compare a conventional (1) two panel photovoltaic solar thermal hybrid (PVT x2) system, (2) side by side photovoltaic and thermal (PV + T) system, (3) two module photovoltaic (PV) system and (4) a two panel solar thermal (T x2) system with identical absorber areas to determine the superior technical solar energy systems for applications with a limited roof area. Three locations, Detroit, Denver and Phoenix, were simulated due to their differences in average monthly temperature and solar flux. The exergy analysis results show that PVT systems outperform the PV + T systems by 69% for all the locations, produce between 6.5% and 8.4% more exergy when matched against the purely PV systems and created 4 times as much exergy as the pure solar thermal system. The results clearly show that PVT systems, which are able to utilize all of the thermal and electrical energy generated, are superior in exergy performance to either PV + T or PV only systems. These results are discussed and future work is outlined to further geographically optimize PVT systems.
Main Points as it relates to this thesis
- Economic feasibility and cost effectiveness are heavily influenced by the arbitrary nature of current economics and politics.
- Exergy comparisons help normalize electrical and thermal energy to ensure a more apples to apples comparison
- PVT proved to have the highest exergy and exergy efficiency, regardless of location. ~36%
Future Work
- Optimization of PVT to better suit applied load
Optimization of a solar photovoltaic thermal (PV/T) water collector based on exergy concept[edit | edit source]
F. Sobhnamayana,a, F. Sarhaddia,a, M.A. Alavib,b, S. Farahata,a, J. Yazdanpanahia,a,
a Department of Mechanical Engineering, University of Sistan and Baluchestan, Zahedan, Iran
b Department of Mechanical Engineering, Mashhad Branch, Islamic Azad University, Mashhad, Iran
Received 11 April 2013, Accepted 30 January 2014, Available online 4 March 2014
DOI: http://dx.doi.org/10.1016/j.renene.2014.01.048
Abstract
In this paper, the optimization of a solar photovoltaic thermal (PV/T) water collector which is based on exergy concept is carried out. Considering energy balance for different components of PV/T collector, we can obtain analytical expressions for thermal parameters (i.e. solar cells temperature, outlet water temperature, useful absorbed heat rate, average water temperature, thermal efficiency, etc.). Thermal analysis of PV/T collector depends on electrical analysis of it; therefore, five-parameter current–voltage (I–V) model is used to obtain electrical parameters (i.e. open-circuit voltage, short-circuit current, voltage and current at the point which has maximum electrical power, electrical efficiency, etc.). In order to obtain exergy efficiency of PV/T collector we need exergy analysis as well as energy analysis. Considering exergy balance for different components of PV/T collector, we obtain the expressions which show the exergy of the different parts of PV/T collector. Some corrections have been done on the above expressions in order to obtain a modified equation for the exergy efficiency of PV/T water collector. A computer simulation program has been developed in order to obtain the amount of thermal and electrical parameters. The simulation results are in good agreement with the experimental data of previous literature. Genetic algorithm (GA) has been used to optimize the exergy efficiency of PV/T water collector. Optimum inlet water velocity and pipe diameter are 0.09 m s−1, 4.8 mm, respectively. Maximum exergy efficiency is 11.36%. Finally, some parametric studies have been done in order to find the effect of climatic parameters on exergy efficiency.
