Ground Cooling System for Improving the Efficiency of Low Temperature Power Generation

2014 ◽  
Author(s):  
Rachana Vidhi ◽  
Pardeep Garg ◽  
Matthew S. Orosz ◽  
D. Yogi Goswami ◽  
Pramod Kumar
Keyword(s):  
Power Generation ◽  
Heat Exchanger ◽  
Las Vegas ◽  
Cooling System ◽  
Cooling Water ◽  
Organic Rankine Cycle ◽  
Ambient Air ◽  
The United States ◽  
Buried Pipe ◽  
Working Fluids

This paper presents an analysis of an organic Rankine cycle (ORC) with dry cooling system aided by an earth-coupled passive cooling system. Several organic fluids were considered as working fluids in the ORC in the temperature range of 125–200°C. An earth-air-heat-exchanger (EAHE) is studied for a location in the United States (Las Vegas) and another in India (New Delhi), to pre cool the ambient air before entering an air-cooled condenser (ACC). It was observed that the efficiency of the system improved by 1–3% for the system located in Las Vegas and fluctuations associated with temperature variations of the ambient air were also reduced when the EAHE system was used. A ground-coupled heat pump (GCHP) is also studied for these locations where cooling water is pre cooled in an underground buried pipe before entering a condenser heat exchanger in a closed loop. The area of the buried pipe and the condenser size are calculated per kW of power generation for various working fluids.

Analysis of a Solar Space Cooling System Using Liquid Desiccants

1990 ◽  
Vol 112 (4) ◽  
pp. 246-250 ◽  
Author(s):  
P. Gandhidasan
Keyword(s):  
Heat Exchanger ◽  
Cooling System ◽  
Cooling Water ◽  
Ambient Air ◽  
Solution Concentration ◽  
Simple Expression ◽  
Ventilation Mode ◽  
Cooling Water Temperature ◽  
System A ◽  
Space Cooling

For tropical countries, solar space cooling is an attractive proposition. Dehumidification of air in hot, humid climates is almost as important as cooling. Removal of moisture from the air is much easier to achieve than cooling the air. The proposed cooling system operates on the ventilation mode. The ambient air is dehumidified using liquid desiccants followed by adiabatic evaporative cooling. The desiccant soon becomes saturated with the water extracted from the air and can be regenerated by using solar energy. For this system, a simple expression is derived in this paper to predict the amount of heat removed from the space to be conditioned in terms of known initial parameters through a simplified vapor pressure correlation and effectiveness of the dehumidifier and the heat exchanger. The effect of ambient air conditions, solution concentration, the cooling water temperature and the effectiveness of the dehumidifier and the heat exchanger on the performance of the cooling system are also discussed in this paper.

scholarly journals Comparative investigation of working fluids for an organic Rankine cycle with geothermal water

2015 ◽  
Vol 36 (2) ◽  
pp. 75-84
Author(s):  
Yan-Na Liu ◽  
Song Xiao
Keyword(s):  
Power Generation ◽  
Pressure Ratio ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Comparative Investigation ◽  
Geothermal Water ◽  
Thermodynamic Investigation ◽  
Working Fluids ◽  
Temperature Heat ◽  
Input Pressure

AbstractIn this paper, the thermodynamic investigation on the use of geothermal water (130 °C as maximum) for power generation through a basic Rankine has been presented together with obtained main results. Six typical organic working fluids (i.e., R245fa, R141b, R290, R600, R152a, and 134a) were studied with modifying the input pressure and temperature to the turbine. The results show that there are no significant changes taking place in the efficiency for these working fluids with overheating the inlet fluid to the turbine, i.e., efficiency is a weak function of temperature. However, with the increasing of pressure ratio in the turbine, the efficiency rises more sharply. The technical viability is shown of implementing this type of process for recovering low temperature heat resource.

Liquid-Coupled Indirect-Transfer Exchanger Application to the Diesel Engine

1979 ◽  
Vol 101 (4) ◽  
pp. 516-523 ◽  
Author(s):  
James C. Eastwood
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Cooling System ◽  
Relative Effectiveness ◽  
Ambient Air ◽  
Air Cooling ◽  
Performance Curves ◽  
Air Cooling System ◽  
Cooling Function ◽  
Low Charge

The efficiency of turbocharged diesel engines can be increased by cooling the charge air. This paper presents a design approach for liquid-coupled indirect-transfer heat exchanger systems to perform the air-cooling function. The two advantages most commonly cited for this approach to charge-air cooling are (1) the heat exchangers involved are easily packaged so that their shapes can be controlled by judicious design, and (2) simple gas ducting allows for compact machinery arrangements and relatively low charge-air pressure drop. An analytical approach to the design of liquid-coupled indirect-transfer heat exchanger systems is presented. Performance curves are constructed on the basis of this analysis. Four important design conditions are evident from the observation of these performance curves including (1) the relative capacity rate combination of the three fluids (ambient air, coupling liquid, and engine charge-air) which yields the highest overall effectiveness, (2) an optimum coupling-liquid flow rate, (3) the relative effectiveness distribution for each of the two component heat exchangers (hot and cold components), and (4) a broad design range for the optimum area distribution between the hot and cold exchangers. These performance curves serve as a guide for the design of a liquid-coupled charge-air cooling system.

scholarly journals Experimental and Techno-Economic Analysis of Solar-Geothermal Organic Rankine Cycle Technology for Power Generation in Nepal

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Suresh Baral
Keyword(s):  
Power Generation ◽  
Heat Source ◽  
Power Output ◽  
Solar Collector ◽  
Hot Spring ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Maximum Temperature ◽  
Working Fluid ◽  
Working Fluids

The current research study focuses on the feasibility of stand-alone hybrid solar-geothermal organic Rankine cycle (ORC) technology for power generation from hot springs of Bhurung Tatopani, Myagdi, Nepal. For the study, the temperature of the hot spring was measured on the particular site of the heat source of the hot spring. The measured temperature could be used for operating the ORC system. Temperature of hot spring can also further be increased by adopting the solar collector for rising the temperature. This hybrid type of the system can have a high-temperature heat source which could power more energy from ORC technology. There are various types of organic working fluids available on the market, but R134a and R245fa are environmentally friendly and have low global warming potential candidates. The thermodynamic models have been developed for predicting the performance analysis of the system. The input parameter for the model is the temperature which was measured experimentally. The maximum temperature of the hot spring was found to be 69.7°C. Expander power output, thermal efficiency, heat of evaporation, solar collector area, and hybrid solar ORC system power output and efficiency are the outputs from the developed model. From the simulation, it was found that 1 kg/s of working fluid could produce 17.5 kW and 22.5 kW power output for R134a and R245fa, respectively, when the geothermal source temperature was around 70°C. Later when the hot spring was heated with a solar collector, the power output produced were 25 kW and 30 kW for R134a and R245fa, respectively, when the heat source was 99°C. The study also further determines the cost of electricity generation for the system with working fluids R134a and R245fa to be $0.17/kWh and $0.14/kWh, respectively. The levelised cost of the electricity (LCOE) was $0.38/kWh in order to be highly feasible investment. The payback period for such hybrid system was found to have 7.5 years and 10.5 years for R245fa and R134a, respectively.

scholarly journals Basic design of a cooling system for nylon 6, 6 process

2018 ◽  
Vol 7 (3) ◽  
pp. 977
Author(s):  
Karthik Silaipillayarputhur Ph. D ◽  
Nasser Al Mulhim ◽  
Abdullah Al Mulhim ◽  
Mohammed Arfaj ◽  
Ahmed Al Naim
Keyword(s):  
Heat Exchanger ◽  
Rate Ratio ◽  
Cooling System ◽  
Ambient Air ◽  
Nylon 6 ◽  
Polymer Fibers ◽  
Basic Design ◽  
Quenching Process ◽  
Pre Treatment ◽  
Selection Of

The project concentrates on the basic design of a cooling system for rapidly cooling nylon 6, 6 polymer fibers using cold air. The ambient air after pre-treatment in the air-washer is available at 72°F all year round. Based on the company’s throughput, it is required to supply (quench) air at 58°F. Nylon 6, 6 polymer after thorough polymerization is distributed through 16 quench cabinets and each quench cabinet requires approximately 530 ft3/min (cubic feet per minute, CFM) of air. The project concentrates on the basic design of a cooling system wherein air at the required mass flow rate is supplied at 58°F for the quenching process. A basic design of the refrigeration cycle and heat exchangers were considered in this work. In the development of the basic design for heat exchanger, performance charts were developed. Performance charts describe the performance of the heat exchanger in terms of fundamental dimensionless parameters. Using performance charts it was clearly seen that increasing the number of transfer units (NTU) doesn’t necessarily increase the rate of heat transfer. Increasing the NTU beyond an optimum value is pointless and increases the capital cost of the heat exchanger. The preliminary design involves selection of appropriate NTU and capacity rate ratio for the heat exchanger. From the capacity rate ratio and NTU, it is fairly straight forward to extrapolate the detailed design for the heat exchanger. A cooling system model was developed for the design process and for the simulation of the cooling system.  

SIMULATION OF ORGANIC RANKINE CYCLE THROUGH FLUEGAS TO LARGE SCALE ELECTRICITY GENERATION PURPOSE

2015 ◽  
Vol 77 (27) ◽  
Author(s):  
Omid Rowshanaie ◽  
Saari Mustapha ◽  
Kamarul Arifin Ahmad ◽  
Hooman Rowshanaie
Keyword(s):  
Heat Exchanger ◽  
Large Scale ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Steady State Condition ◽  
Working Fluids ◽  
Tube Heat Exchanger ◽  
Heat Transfer Capacity ◽  
Mass Flow Rates ◽  
Shell And Tube

A simulation model of Organic Rankine Cycle (ORC) was developed with HYSYS software driven by R245fa, with NOVEC7000 and R141b as working fluids and Fluegas of boilers as a heat source of shell and tube Heat Exchanger to generate large scale electricity. The initial working condition was in subcooled liquid and steady state condition. R141b was found to generate the highest electricity power increment in specific mass flow rates and inlet pressures of Expander because of approaching its critical temperature to inlet Fluegas temperature. Howeever, in terms of economic considerations and cost of shell and tube Heat Exchanger that related to total heat transfer capacity, NOVEC7000 is the optimum selection. Furthermore, R245fa has the highest total effiiciency of ORC compared with other working fluids in this study.

Analysis of Intercooler in PEM Fuel Cell Systems

Volume 3 ◽  
2004 ◽  
Author(s):  
Takamasa Ito ◽  
Jinliang Yuan ◽  
Bengt Sunde´n
Keyword(s):  
Heat Exchanger ◽  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Cooling System ◽  
Ambient Air ◽  
Proton Exchange ◽  
High Mass ◽  
Air Cooling ◽  
Cell Systems ◽  
Cold Stream

Heat exchangers are used in proton exchange membrane fuel cell systems (PEMFCs) for stack cooling, intercooling, water condensation and fuel reforming. Especially, the heat exchanger for the intercooling before the humidifier is investigated in this paper. It is found that, at high pressure or high mass flow rate, the need to cool the air (oxidant) is large. The heat exchanger uses coolant water from the stack cooling system or ambient air as the cold stream. With water-cooling, the volume of the heat exchanger will be small. However, difficulties exist because the small available temperature difference. Air-cooling can be used over a wide operating range but the heat exchanger volume will be large.

Fluid Mechanical Design of a Dry-Cooling System Thermal Storage Reservoir, or Stratification Minimization in Horizontal Channel Flow

1983 ◽  
Vol 105 (2) ◽  
pp. 174-180 ◽  
Author(s):  
E. C. Guyer ◽  
M. W. Golay
Keyword(s):  
Cold Water ◽  
Cooling System ◽  
Plug Flow ◽  
Cooling Water ◽  
Thermal Storage ◽  
The United States ◽  
Hot Water ◽  
Flow Mode ◽  
Storage Reservoir ◽  
Dry Cooling

The use of a capacitive Thermal Storage Reservoir (TSR) initially filled with cold water as part of a dry cooling system for a central power station is attractive economically if the reservoir can be designed to operate in an approximate “plug-flow” mode—discharging cold water to the condenser and filling with hot water from the cooling tower. Such a system would avoid the loss of station capacity associated with dry cooling at high dry-bulb temperatures, and the economic penalties due to such losses when they are coincident with electrical demand peaks (as is common in the United States). The initial employment of this concept is most likely to occur in solar-powered thermal electric power stations in arid climates in view of the likely low thermal efficiency and limited cooling water access of such plants. Buoyant flow stratification hinders attaining this goal since it can cause “short circuiting” of the TSR. For adequate flow control, a long narrow reservoir configuration is desirable. In investigating the behavior of such a TSR experimentally, it was found over the range of cases examined that injection of water into a long narrow reservoir which is initially at a different temperature always results in a stratified flow superimposed upon the gross plug flow of the TSR, and it was found that acceptable performance could be obtained inexpensively by placing flow-constricting barriers at regular intervals along the reservoir length. Experimental investigation of barrier design and spacing has permitted definition of a practical prototype TSR design which provides approximately 87 percent of the thermal capacity of a plug flow TSR.

scholarly journals Optimization for Circulating Cooling Water Distribution of Indirect Dry Cooling System in a Thermal Power Plant under Crosswind Condition with Evolution Strategies Algorithm

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1167
Author(s):  
Zhao Li ◽  
Huimin Wei ◽  
Tao Wu ◽  
Xiaoze Du
Keyword(s):  
Heat Exchanger ◽  
Power Plant ◽  
Ambient Temperature ◽  
Water Distribution ◽  
Cooling System ◽  
Thermal Power ◽  
Cooling Water ◽  
Evolution Strategies ◽  
Circulating Cooling Water ◽  
Dry Cooling

Crosswind has an adverse impact on the performance of an indirect dry cooling system. In order to mitigate the adverse influence, this study redistributed the circulating cooling water among air-cooled heat exchanger sectors so that the performance of the indirect dry cooling system could be improved. An evolution strategies algorithm combined with numerical effectiveness-based heat exchanger model was established to minimize the operation costs of the whole system. Based on a 660 MW practical power plant, optimal circulating cooling water operation strategies under varied crosswind speeds and ambient temperatures were calculated to show its application. According to the calculated results, the performance of the indirect dry cooling system could be enhanced by optimizing circulating cooling water distribution under any crosswind speed, especially under high ambient wind speeds. There is a slight promotion of the coal savings with a rise in ambient temperature: improvements of about 5%. The standard coal consumption rate could save as much as 2.50 g/kWh under crosswind speed of 10 m s−1 and ambient temperature of 32 °C, compared to the 0.1 g/kWh under crosswind speed of 2 m s−1 and ambient temperature of 32 °C.

Sign in / Sign up

Export Citation Format

Share Document