Energy, exergy, and economic analysis of a geothermal power plant

Energy conservation and emission reduction are inevitable strategies for alleviating energy shortages and environmental pollution, which can be achieved by improving the energy utilization efficiency and using cleaner energy. Waste heat recovery (WHR) is an effective strategy to improve the energy utilization efficiency of a system. [1] A common WHR approach involves the addition of a bottoming cycle, [2] such as the Rankine (RC), flash, Kalina (KC), Stirling, and Brayton cycles, with each bottoming cycle exhibiting a different WHR potential for various temperature ranges. In this regard, waste heat is typically categorized into low-(<230 °C), medium-(230-650 °C), and high-temperature residual heat (>650 °C). [3] Varma et al. [4] performed a comparative study of the performance of the organic Rankine cycle (ORC), organic flash cycle (OFC), and KC for recovering low-grade waste heat and found that the OFC, ORC, and KC with a specific temperature and solution concentration exhibited the highest power generation, efficiency, and power output among the investigated cycles, respectively. Zhang et al. [5] compared the steam Rankine cycle (SRC), ORC, and steam-organic Rankine cycle (S-ORC) and concluded that the ORC exhibited optimal thermodynamic performance at residual heat temperatures of 150-210 °C, whereas the S-ORC demonstrated superior performance at 210-350 °C. Liu et al. [6] compared the thermodynamic performance of the supercritical CO 2 Brayton cycle (S-CO 2 ) and SRC at high temperatures and found that the performance of S-CO 2 was superior to that of the SRC. Moreover, the performance parameters of the equipment were analyzed from the perspective of energy conservation. The aforementioned scholars compared the performance of the ORC, OFC, KC, SRC, S-ORC, and S-CO 2 cycles for recovering waste heat of different grades. These studies highlight the suitability of the S-CO 2 and ORC for high-temperature and low-grade WHR, respectively.China has prioritized the achievement of carbon peak and carbon neutrality to mitigate the severe problem of climate change as an environmental protection strategy and as an important basis for national economic competitiveness in the future. Therefore, the use of CO 2 as a working fluid must be reassessed. CO 2 has recently been shown to exhibit tremendous potential as

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“…[ 31 ] For the operating and maintenance cost, 3% of the initial cost is considered. And, it can be calculated by the following equation [ 30,32 ]

O M = \sum_{N = 1}^{20} \frac{0.04 \times total cost}{{false(1 + 0.08 false)}^{N}}

where OM is the operating and maintenance cost. Total cost represents the total investment costs.…”

Section: Modelingmentioning

confidence: 99%

Energy, Exergy, Economic, Exergoeconomic, and Exergoenvironmental (5E) Analyses and Optimization of a Novel Three‐Stage Cascade System Based on Liquefied Natural Gas Cold Energy

Shang

Pan

et al. 2022

Energy Tech

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“…As the world's largest energy producer and consumer, China is developing clean, carbon-free and efficient new energy sources to achieve the goal of carbon neutralization and promote a harmonious relationship between humans and nature. Geothermal energy is one of the most important renewable energy resources because of its great exploitation potential and abundant reserves (Kazemi and Ehyaei, 2018;Chen et al, 2019). Therefore, paying attention to the rational development and utilization of geothermal resources is of great significance to realize the energy revolution.…”

Section: Introductionmentioning

confidence: 99%

Comparative study on the thermal performance and economic efﬁciency of vertical and horizontal ground heat exchangers

Cui

Jiao

2022

Adv. Geo-Energy Res.

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The ground-coupled heat pump is a shallow geothermal exploitation method taking soil as the thermal energy source. The ground heat exchanger is an important component of this system, which includes vertical or horizontal configurations. However, to the best of our knowledge, few studies exist involving the comparison of thermal performances and installation costs of two heat exchanger types considering the influence of ground climate, which makes the selection of heat exchanger configuration challenging for a specific field application. Hence, a 3-dimensional numerical model considering the variations of atmospheric conditions and soil water content is constructed in this paper. Based on this model, the thermal performances and economical efficiencies of vertical and horizontal ground heat exchangers are compared. The results indicate that the thermal performance difference between the two heat exchangers is greater in winter than in summer. The thermal performance is hardly influenced by the injection mass flow rate, while it is considerably affected by the length of heat exchanger. The thermal power rises linearly with the increase in heat exchanger length, and the increment of the vertical ground heat exchanger is higher. In addition, when the heat exchanger length is shorter than 40 m, the installation cost and thereby the total cost of the horizontal ground heat exchanger is considerably higher. With regard to both the thermal performance and economic efficiency, a vertical ground heat exchanger is only recommended when installing a single shallow ground heat exchanger.

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“…Several studies have been reported in recent years on energy, exergy, economic and environmental analyses, and optimization of various power generation systems, including combined heat and power, renewable energy, and other plants [19][20][21][22][23][24][25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic Optimization of a Geothermal Power Plant with a Genetic Algorithm in Two Stages

et al. 2020

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Due to the harmful effects and depletion of non-renewable energy resources, the major concerns are focused on using renewable energy resources. Among them, the geothermal energy has a high potential in volcano regions such as the Middle East. The optimization of an organic Rankine cycle with a geothermal heat source is investigated based on a genetic algorithm having two stages. In the first stage, the optimal variables are the depth of the well and the extraction flow rate of the geothermal fluid mass. The optimal value of the depth of the well, extraction mass flow rate, and the geothermal fluid temperature is found to be 2100 m, 15 kg/s, and 150 °C. In the second stage, the efficiency and output power of the power plant are optimized. To achieve maximum output power as well as cycle efficiency, the optimization variable is the maximum organic fluid pressure in the high-temperature heat exchanger. The optimum values of energy efficiency and cycle power production are equal to 0.433 MW and 14.1%, respectively.

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Energy, exergy, and economic analysis of a geothermal power plant

Cited by 23 publications

References 36 publications

Energy, Exergy, Economic, Exergoeconomic, and Exergoenvironmental (5E) Analyses and Optimization of a Novel Three‐Stage Cascade System Based on Liquefied Natural Gas Cold Energy

Energy, Exergy, Economic, Exergoeconomic, and Exergoenvironmental (5E) Analyses and Optimization of a Novel Three‐Stage Cascade System Based on Liquefied Natural Gas Cold Energy

Comparative study on the thermal performance and economic efﬁciency of vertical and horizontal ground heat exchangers

Thermodynamic Optimization of a Geothermal Power Plant with a Genetic Algorithm in Two Stages

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