Loading...

Modeling of Optimal Design of Solar Collector in Multi-energy Hybrid Systems based on Minimum Exergy Destruction

Tavakol Moghaddam, Yasaman | 2019

989 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 52252 (46)
  4. University: Sharif University of Technology
  5. Department: Energy Engineering
  6. Advisor(s): Saboohi, Yadollah; Fathi, Amir Hossein
  7. Abstract:
  8. Concentrated photovoltaic systems (CPVs) allow simultaneous production of electrical energy and high-temperature thermal energy. These systems consist of a concentrator for collecting solar rays onto the surface of the recipient cells. Moreover, these systems are always facing the sun using a sun tracker. The heat generated by these systems can be used in industrial processes, heating, cooling, and water desalinating. Given the concurrent generation of power and high-temperature heat, it is possible to achieve higher efficiency than that of conventional solar systems. Furthermore, the electrical efficiency is also higher than conventional systems due to the use of multi-junction solar cells and the fact that these cells show higher efficiency against concentrated light. The development of the model of the system to assess the optimal design of the concentrator is a fundamental challenge and one of the key issues for improving the overall efficiency of these systems. The optimized design can be effective in increasing the share of hybrid systems in energy supply. Most solar concentrators, such as parabolic concentrators, collect non-uniform light onto the receiver. This non-uniform intensity reduces the output power, increases exergy destruction and reduces the lifespan of the device. Therefore, the uniformity of the irradiance and the appropriateness of the intensity of the light in the receiver are considered as critical properties of the system. The designed system uses thermophotovoltaic cells due to their higher temperature tolerance. This dissertation focuses on the design of the concentrator of a CPV system to increase the efficiency and reduce the exergy destruction of the system, which concentrates sunlight uniformly onto the receiver. Firstly, by solving appropriate differential equations, an imaging solar concentrator is designed with uniform irradiance based on parameters such as the size of the receiver, the concentrator size, and the receiver distance from the concentrator. The system is then evaluated using the Monte Carlo method and ray tracing. Finally, using the developed model, the optimal concentrator to provide the average household energy demand is designed by intelligent optimization. The electrical output of the optimal system is 4.9 kW and its daily power generation is 3 kWh. The radius of the receiver in the optimal system is 21.57 cm , the radius of its concentrator is 267.75 cm, and the distance between the receiver and the concentrator is 316.12 cm . The energy efficiency of the optimal system is 76.09%, its exergy efficiency is 67.91%, and its temperature is 997℃
  9. Keywords:
  10. Solar Energy ; Solar Collectors ; Exergy ; Optical Model ; Monte Carlo Method ; Intelligent Optimization

 Digital Object List

 Bookmark

...see more