A224 Research on Low-grade Thermal Energy Conversion using HFC245fa as working fluid

2012 ◽  
Vol 2012.17 (0) ◽  
pp. 249-252
Author(s):  
Yasuyuki IKEGAMI ◽  
Takafumi MORISAKI
Keyword(s):  
Energy Conversion ◽  
Thermal Energy ◽  
Working Fluid ◽  
Low Grade ◽  
Thermal Energy Conversion

Direct Method to Maximize Net Power Output of Rankine Cycle in Low-Grade Thermal Energy Conversion

2010 ◽  
Vol 2 (2) ◽  
Author(s):  
Faming Sun ◽  
Yasuyuki Ikegami
Keyword(s):  
Energy Conversion ◽  
Thermal Energy ◽  
Power Output ◽  
Direct Method ◽  
Rankine Cycle ◽  
Working Fluid ◽  
Carnot Cycle ◽  
Low Grade ◽  
Thermal Energy Conversion ◽  
Net Power Output

Using ammonia as working fluid, enthalpy equations corresponding to every point in Rankine cycle for low-grade thermal energy conversion (LTEC) are presented by employing curve-fitting method. Analytical equations of Rankine cycle analysis are thus set up. In terms of temperatures of the evaporator and condenser, the equation related to Rankine cycle net power output is then achieved. Furthermore, by using theoretical optimization method, the results of the maximum net power output of a Rankine cycle in LTEC are also reported. This study extends the recent flurry of publications about Rankine cycle power optimization in LTEC, which modified the ideal Rankine cycle to a Carnot cycle by using an average entropic temperature to achieve the theoretical formulas. The proposed method can better reflect the performance of Rankine cycle in LTEC since the current work is mainly based on the direct simulations of every enthalpy points in Rankine cycle. Moreover, the proposed method in this paper is equally applicable for other working mediums, such as water and R134a.

Stack Thermo-Osmotic System for Low-Grade Thermal Energy Conversion

2021 ◽  
Author(s):  
Ji Li ◽  
Zikang Zhang ◽  
Runze Zhao ◽  
Bo Zhang ◽  
Yunmin Liang ◽  
...  
Keyword(s):  
Energy Conversion ◽  
Thermal Energy ◽  
Low Grade ◽  
Thermal Energy Conversion ◽  
Osmotic System

scholarly journals Determine the best location for Ocean Thermal Energy Conversion (OTEC) in Iranian Seas

2016 ◽  
Vol 10 (5) ◽  
pp. 32 ◽  
Author(s):  
Ashrafoalsadat Shekarbaghani
Keyword(s):  
Energy Conversion ◽  
Thermal Energy ◽  
Caspian Sea ◽  
Power Plants ◽  
Sea Water ◽  
Working Fluid ◽  
The South ◽  
Ocean Thermal Energy Conversion ◽  
Thermal Energy Conversion ◽  
Ocean Thermal Energy

Two-thirds of the earth's surface is covered by oceans. These bodies of water are vast reservoirs of renewable energy.<strong> </strong>Ocean Thermal Energy Conversion technology, known as OTEC, uses the ocean’s natural thermal gradient to generate power. In geographical areas with warm surface water and cold deep water, the temperature difference can be leveraged to drive a steam cycle that turns a turbine and produces power. Warm surface sea water passes through a heat exchanger, vaporizing a low boiling point working fluid to drive a turbine generator, producing electricity. OTEC power plants exploit the difference in temperature between warm surface waters heated by the sun and colder waters found at ocean depths to generate electricity. This process can serve as a base load power generation system that produces a significant amount of renewable, non-polluting power, available 24 hours a day, seven days a week. In this paper investigated the potential of capturing electricity from water thermal energy in Iranian seas (Caspian Sea, Persian Gulf and Oman Sea). According to the investigated parameters of OTEC in case study areas, the most suitable point in Caspian Sea for capturing the heat energy of water is the south part of it which is in the neighborhood of Iran and the most suitable point in the south water of Iran, is the Chahbahar port.

Effect of Entrainment Ratio and Subcooling Degree on Dual System of Cooling-Thermal Energy Conversion Applying Ejector

2017 ◽  
Vol 379 ◽  
pp. 140-148
Author(s):  
Jung In Yoon ◽  
Ho Saeng Lee ◽  
Chang Hyo Son ◽  
Sung Hoon Seol ◽  
Kwang Seok Lee ◽  
...  
Keyword(s):  
Energy Conversion ◽  
Thermal Energy ◽  
Simulation Analysis ◽  
Cooling Capacity ◽  
Dual System ◽  
Working Fluid ◽  
Generation System ◽  
Entrainment Ratio ◽  
Thermal Energy Conversion ◽  
Ocean Thermal Energy

This study proposes a system called 'dual system of cooling-thermal energy conversion applying ejector', which practically applies an ejector to an ocean thermal energy conversion (OTEC) system. The proposed system presents higher system efficiency, owing to the application of an ejector, and reduced initial and operating costs. The main results, obtained from simulation analysis, are as follows: the cooling capacity tended to decrease as the entrainment ratio increased, and the system using R134a generally presented the highest cooling capacity and COP. In terms of generation system, the highest turbine gross power was obtained when the R134a working fluid was applied. The efficiency of the system decreased as the entrainment ratio increased. Finally, the application of the ejector enhanced the efficiency of the generation system, using R134a, by approximately 50%, from 4.73% to 7.10% at the entrainment ratio of 0.1.

A Simulation Model for Hot Spring Thermal Energy Conversion Plant With Working Fluid of Binary Mixtures

2004 ◽  
Vol 126 (3) ◽  
pp. 445-454 ◽  
Author(s):  
Ou Bai ◽  
Masatoshi Nakamura ◽  
Yasuyuki Ikegami ◽  
Haruo Uehara
Keyword(s):  
Energy Conversion ◽  
Binary Mixtures ◽  
Thermal Energy ◽  
Hot Spring ◽  
Structural Features ◽  
Working Fluid ◽  
State Variables ◽  
Power Cycle ◽  
Thermal Energy Conversion ◽  
Dependent State

Hot spring thermal energy conversion (STEC) is a system that converts heat energy into electricity using the temperature difference between hot spring water and sea/river water. This paper describes dynamic model construction for the transient performance of STEC plant, which uses a recently developed power cycle with binary mixtures as working fluid. The mathematical models were constructed based on thermodynamics and structural features of the power cycle for representing the timely dependent state variables of the working fluid. Confidence in the accuracy of the developed models has been established by comparison of the simulation results with those obtained experimentally in a pilot STEC plant.

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