Progress of Closed-Cycle OTEC and Study of a New Cycle of OTEC

2011 ◽  
Vol 354-355 ◽  
pp. 275-278
Author(s):  
Wei Min Liu ◽  
Feng Yun Chen ◽  
Yi Qiang Wang ◽  
Wei Jun Jiang ◽  
Ji Guang Zhang
Keyword(s):  
Temperature Difference ◽  
Thermal Efficiency ◽  
Rankine Cycle ◽  
Ammonia Solution ◽  
Ocean Temperature ◽  
Closed Cycle ◽  
Kalina Cycle ◽  
Cycle System ◽  
Working Medium ◽  
Regenerative Cycle

OTEC has the advantages of large reserves, renewable, stable and clean without pollution. However the smaller ocean temperature-difference results in the lower thermal efficiency. Based on the research of Rankine cycle, Kalina cycle, Uehara cycle, a new closed-cycle system (GuoHai cycle) has been studied, this cycle system uses ammonia-water mixtures as working medium. Indirect regenerative cycle and poor ammonia solution regenerative cycle is adopted in order to improve the thermal efficiency of the system.

scholarly journals Thermal performance comparison of Rankine cycle, reheat cycle and regenerative cycle with the same initial and final parameters

2021 ◽  
Vol 245 ◽  
pp. 03015
Author(s):  
Yarong Wang ◽  
Peirong Wang
Keyword(s):  
Thermal Efficiency ◽  
Thermal Cycle ◽  
Power Plants ◽  
Mechanical Energy ◽  
Rankine Cycle ◽  
Performance Comparison ◽  
Factors Affecting ◽  
Working Medium ◽  
Generation Cost ◽  
Regenerative Cycle

The conversion between thermal energy and mechanical energy can be realized through the thermal cycle of working medium in a series of power plants. For the thermodynamic analysis of the thermal cycle, it mainly analyzes the thermal efficiency and steam consumption rate of the cycle to analyze the main factors affecting the thermal efficiency of the cycle, and the measures to improve the thermal efficiency, in order to reduce the fuel consumption and reduce the power generation cost.

scholarly journals Utilization of Indonesia’s Hot Spring Sources for Electricity using Kalina Cycle and Organic Rankine Cycle

2018 ◽  
Vol 31 ◽  
pp. 01002 ◽  
Author(s):  
Grano Prabumukti ◽  
Widodo Wahyu Purwanto
Keyword(s):  
Heat Source ◽  
Thermal Efficiency ◽  
Hot Springs ◽  
Hot Spring ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Working Fluid ◽  
Power Capacity ◽  
Spring Temperature ◽  
Kalina Cycle

Indonesia posses 40% of the world's geothermal energy sources. The existence of hydrothermal sources is usually characterized by their surface manifestations such as hot springs, geysers and fumarole. Hot spring has a potential to be used as a heat source to generate electricity especially in a rural and isolated area. Hot springs can be converted into electricity by binary thermodynamic cycles such as Kalina cycle and ORC. The aim of this study is to obtain the best performances of cycle configuration and the potential power capacity. Simulation is conducted using UNISIM software with working fluid and its operating condition as the decision variables. The simulation result shows that R1234yf and propene with simple ORC as desired working fluid and cycle configuration. It reaches a maximum thermal efficiency up to 9.6% with a specific turbine inlet pressure. Higher temperature heat source will result a higher thermal efficiency‥ Cycle thermal efficiency varies from 4.7% to 9.6% depends on source of hot spring temperature. Power capacity that can be generated using Indonesia’s hot spring is ranged from 2 kWe to 61.2 kWe. The highest capacity located in Kawah Sirung and the least located in Kaendi.

The Performance of the Kalina Cycle System 11(KCS-11) With Low-Temperature Heat Sources

2007 ◽  
Vol 129 (3) ◽  
pp. 243-247 ◽  
Author(s):  
H. D. Madhawa Hettiarachchi ◽  
Mihajlo Golubovic ◽  
William M. Worek ◽  
Yasuyuki Ikegami
Keyword(s):  
Low Temperature ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Inlet Pressure ◽  
Cycle Performance ◽  
Heat Sources ◽  
Kalina Cycle ◽  
Cycle System ◽  
Temperature Heat ◽  
Cycle Efficiency

The possibility of exploiting low-temperature heat sources has been of great significance with ever increasing energy demand. Optimum and cost-effective design of the power cycles provide a means of utilization of low-temperature heat sources which might otherwise be discarded. In this analysis, the performance of the Kalina cycle system 11 (KCS11) is examined for low-temperature geothermal heat sources and is compared with an organic Rankine cycle. The effect of the ammonia fraction and turbine inlet pressure on the cycle performance is investigated in detail. Results show that for a given turbine inlet pressure, an optimum ammonia fraction can be found that yields the maximum cycle efficiency. Further, the maximum cycle efficiency does not necessarily yield the optimum operating conditions for the system. In addition, it is important to consider the utilization of the various circulating media (i.e., working fluid, cooling water, and heat resource) and heat exchanger area per unit power produced. For given conditions, an optimum range of operating pressure and ammonia fraction can be identified that result in optimum cycle performance. In general, the KCS11 has better overall performance at moderate pressures than that of the organic Rankine cycle.

Thermodynamic Analysis and Comparison Study of an Organic Rankine Cycle (ORC) and a Kalina Cycle for Waste Heat Recovery of Compressor Intercooling

2014 ◽  
Author(s):  
Jianyong Wang ◽  
Jiangfeng Wang ◽  
Pan Zhao ◽  
Yiping Dai ◽  
Yan Peng
Keyword(s):  
Power Consumption ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Inlet Pressure ◽  
Kalina Cycle ◽  
Cycle System ◽  
Turbine Inlet

The intercooling of multi-stage compressors contributes to reducing the power consumption of compressors and the waste heat is generally taken away by cooling water, which is a great waste of energy. This paper employs an organic Rankine cycle (ORC) or a Kalina cycle to recover the waste heat of compressor intercooling. The mathematical models of ORC and Kalina cycle are established by MATLAB software to simulate the ORC system and the Kalina cycle system under steady-state conditions. A parametric analysis is conducted to evaluate the effects of several key thermodynamic parameters on the system performance. In addition, a parametric optimization is carried out to find the optimum performance of waste heat recovery system from thermodynamic aspect. The results showed that, for the ORC system, there is an optimum value of turbine inlet pressure with the state of working fluid being saturated vapor that yields the minimum net power consumption of the system; whereas for the Kalina cycle system, in some ranges of accessible operation conditions, a higher turbine inlet pressure, a lower turbine inlet temperature and a lower ammonia mass fraction of basic solution could obtain a less net power consumption of the system. The optimization results indicated that the Kalina cycle system shows a better performance than the ORC system.

EXPERIMENTAL STUDY ON PUMP APPLIED IN ORGANIC RANKINE CYCLE SYSTEM

2017 ◽  
Author(s):  
Weicong Xu ◽  
Li Zhao ◽  
Shuai Deng ◽  
Jianyuan Zhang ◽  
Wen Su
Keyword(s):  
Experimental Study ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Cycle System

scholarly journals Performance Analysis and Optimization for Irreversible Combined Carnot Heat Engine Working with Ideal Quantum Gases

Entropy ◽  
2021 ◽  
Vol 23 (5) ◽  
pp. 536
Author(s):  
Lingen Chen ◽  
Zewei Meng ◽  
Yanlin Ge ◽  
Feng Wu
Keyword(s):  
Power Output ◽  
Thermal Efficiency ◽  
Combined Cycle ◽  
Quantum Gases ◽  
Carnot Cycle ◽  
Leakage Loss ◽  
Optimal Power ◽  
Heat Leakage ◽  
Working Medium ◽  
Ideal Quantum

An irreversible combined Carnot cycle model using ideal quantum gases as a working medium was studied by using finite-time thermodynamics. The combined cycle consisted of two Carnot sub-cycles in a cascade mode. Considering thermal resistance, internal irreversibility, and heat leakage losses, the power output and thermal efficiency of the irreversible combined Carnot cycle were derived by utilizing the quantum gas state equation. The temperature effect of the working medium on power output and thermal efficiency is analyzed by numerical method, the optimal relationship between power output and thermal efficiency is solved by the Euler-Lagrange equation, and the effects of different working mediums on the optimal power and thermal efficiency performance are also focused. The results show that there is a set of working medium temperatures that makes the power output of the combined cycle be maximum. When there is no heat leakage loss in the combined cycle, all the characteristic curves of optimal power versus thermal efficiency are parabolic-like ones, and the internal irreversibility makes both power output and efficiency decrease. When there is heat leakage loss in the combined cycle, all the characteristic curves of optimal power versus thermal efficiency are loop-shaped ones, and the heat leakage loss only affects the thermal efficiency of the combined Carnot cycle. Comparing the power output of combined heat engines with four types of working mediums, the two-stage combined Carnot cycle using ideal Fermi-Bose gas as working medium obtains the highest power output.

System modification and thermal efficiency study on the semi-closed cycle of supercritical carbon dioxide

2021 ◽  
Vol 241 ◽  
pp. 114272
Author(s):  
Bowen Li ◽  
Shaozeng Sun ◽  
Linyao Zhang ◽  
Dongdong Feng ◽  
Yijun Zhao ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Thermal Efficiency ◽  
Closed Cycle ◽  
Supercritical Carbon
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