Exergy Analysis of Two Kinds of Solar-Driven Cogeneration Systems in Lhasa, Tibet, China

Abstract

In this study, an exergy analysis of two kinds of solar-driven cogeneration systems consisting of solar collectors and an organic Rankine cycle (ORC) is presented for series mode and parallel mode. Three kinds of solar collectors are considered: flat-plate collectors (FPC), evacuated tube collectors (ETC), and parabolic trough collectors (PTC). This study mainly compares the exergy output of the two kinds of solar cogeneration systems under different temperatures of the return heating water and different inlet temperatures of the solar collectors. This study shows that, from the perspective of Wnet or E̲n, the parallel mode is superior to the series mode. From the perspective of Ez, the parallel mode is superior to the series mode when the solar collector is FPC; however, the series mode is superior to the parallel mode when the solar collector is PTC. When the solar collector is ETC, the result depends on the temperature of the return heating water. When the temperature of the return heating water is low (below 46°C), the series mode is better, and when the temperature of the return heating water is high (above 46°C), the parallel mode is better.

Optimal Scheduling Method of Cogeneration System with Heat Storage Device Based on Memetic Algorithm

“…Literature [9] integrated phase-change material buildings as heat storage devices for heat storage, reducing system heat supply and forced electricity output. Literature [10][11][12] proposed a new type of solar heat and power cogeneration system composed of solar collectors to alleviate the heating load of buildings. Literature [13] used cogeneration units, auxiliary heat boilers, and heat pumps to coordinate heat supply and improve the structure of traditional cogeneration units.…”

Form and Operation Mode Analysis of a Novel Solar-Driven Cogeneration System with Various Collector Types

“…According to the literature [27], the power consumption of the cooling device is given by equation (12), where w cond is the power consumption of the cooling device per unit cooling load. 5 International Journal of Photoenergy 3.5.…”

“…Through literature review, there are very few studies on the combination of the solar collector and ORC thermal generator set to realize heating and power generation, and the research mainly lies in the thermodynamic analysis of the system [2][3][4][5][6][7][8][9][10][11][12]. Zhai et al [2] studied a novel hybrid solar trigeneration system based on the use of a parabolic trough collector (PTC), a screw expander, and a silica gel-water adsorption cooling module in Dunhuang, China.…”

“…They found that R245ca has the highest net annual work output of the investigated working fluids. Zhang et al [12] compared two kinds of solar-driven cogeneration systems in Lhasa and found that parallel mode is superior to the series mode when the solar collector is FPC and series mode is superior to the parallel mode when the solar collector is PTC and when the solar collector is ETC; it depends on the temperature of the return heating water.…”

Exergy analysis of district energy systems and comparison of their exergetic, energetic and environmental performance

“…Meanwhile, it is important to simultaneously consider the amount of CO2 emission from those energy sources to find a connection between exergy performance and environmental pollution of the system (Rosen, 2002). For example, energy sources such as fossil fuels contain a high amount of exergy and huge amounts of emissions at the same time, while solar energy, which is thermal radiation emitted at the temperature of the sun (approximately 5800 K), contains much energy and exergy without any direct CO2 emission, though the maximum exergy efficiency of a solar trigeneration system is less than 5% (Zhang, et al, 2018). This study analyzes the exergy performance of the process of heat/electricity generation (e.g.…”