Investigation on Operating Processes for a New Solar Cooling Cogeneration Plant

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
R. Shankar ◽  
T. Srinivas
Keyword(s):  
Power Generation ◽  
Thermal Efficiency ◽  
Power Efficiency ◽  
Climatic Conditions ◽  
Coefficient Of Performance ◽  
Maximum Temperature ◽  
Specific Power ◽  
Working Fluid ◽  
Water Mixture ◽  
Cogeneration Plant

Some commercial units and industries need more amount of cooling than the power such as cold storage, shopping complex, etc. In this work, a new cooling cogeneration cycle (Srinivas cycle) has been proposed and solved to generate more cooling with adequate power generation from single source of heat at hot climatic conditions with ammonia–water mixture as a working fluid. The operational processes conditions for the proposed cooling cogeneration plant are different compared to the power-only (Kalina cycle system) system and cooling-only (vapor absorption refrigeration) system. This work focused to generate the optimum working conditions by parametric analysis from thermodynamic point of view. An increase in cycle maximum temperature is only supporting the power generation but not the cooling output. Cooling output is also 15 times more than power generation. So, it has been recommended to operate the integrated plant with low temperature heat recovery. The resulted cycle thermal efficiency, plant thermal efficiency, specific power, specific cooling, cycle power efficiency, cycle coefficient of performance (COP), and solar collector's specific area are 27%, 10%, 15 kW, 220 kW, 1.8%, 0.25, and 10 m2/kW, respectively.

The Heat Transfer Performance of Porous Gas Turbine Blades

1968 ◽  
Vol 72 (696) ◽  
pp. 1087-1094 ◽  
Author(s):  
F. J. Bayley ◽  
A. B. Turner
Keyword(s):  
Gas Turbine ◽  
Turbine Blades ◽  
Engine Performance ◽  
Operating Conditions ◽  
Maximum Temperature ◽  
Specific Power ◽  
Working Fluid ◽  
Inlet Temperature ◽  
Turbine Inlet ◽  
Compression And Expansion

It is well known that the performance of the practical gas turbine cycle, in which compression and expansion are non-isentropic, is critically dependent upon the maximum temperature of the working fluid. In engines in which shaft-power is produced the thermal efficiency and the specific power output rise steadily as the turbine inlet temperature is increased. In jet engines, in which the gas turbine has so far found its greatest success, similar advantages of high temperature operation accrue, more particularly as aircraft speeds increase to utilise the higher resultant jet velocities. Even in high by-pass ratio engines, designed specifically to reduce jet efflux velocities for application to lower speed aircraft, overall engine performance responds very favourably to increased turbine inlet temperatures, in which, moreover, these more severe operating conditions apply continuously during flight, and not only at maximum power as with more conventional cycles.

scholarly journals EFFICIENCY OF THE REGENERATIVE CYCLE OF BRIGHTON WITH VARIABLE THERMOPHYSICAL PROPERTIES OF THE WORKING FLUID (Part 2)

2018 ◽  
Vol 41 (3) ◽  
pp. 5-13
Author(s):  
A.A. Khalatov ◽  
S.D. Severin ◽  
O.S. Stupak ◽  
O.V. Shihabutinova
Keyword(s):  
Moisture Content ◽  
Thermophysical Properties ◽  
Thermal Efficiency ◽  
Second Law Of Thermodynamics ◽  
Maximum Temperature ◽  
Working Fluid ◽  
Thermodynamic Efficiency ◽  
Carnot Cycle ◽  
Regenerative Cycle ◽  
The Ideal

The data about thermodynamic efficiency of the ideal Brighton cycle with heat regeneration with constant thermophysical properties of the working fluid, as well as the Brighton cycle with heat recovery and the wetting of the working fluid at the inlet to the turbine (with variable thermophysical properties of the working fluid). The inapplicability of comparison of the thermal efficiency of the Brighton cycle with heat recovery and the wetting of the working fluid at the inlet to the turbine with the thermal efficiency of the equivalent ideal Carnot cycle is shown. The analysis of the thermodynamic efficiency of an ideal regenerative Brighton cycle with a decrease in the working body at the entrance to the turbine allows us to make the following conclusions: With the growth of the mass moisture content of the working fluid when entering the turbine, the thermal efficiency of the regenerative cycle increases, but decreases with an increase in the degree of increase in the pressure level in the cycle. High values ​​of the thermal efficiency of the cycle () can be achieved with relatively small values ​​of the degree of increase in the pressure in the cycle () and high (up to d = 0,5) values ​​of the mass moisture content of the working body when entering the turbine. It is shown that under certain conditions the thermal efficiency of the regenerative cycle with the decrease of the working body when entering the turbine may be greater than the thermal efficiency of a similar ideal Carnot cycle, which does not contradict the second law of thermodynamics, since the condition for the implementation of the Carnot cycle is the immutability of the thermophysical properties of the working body in a loop In this regard, the use of the expression for the thermal efficiency of the ideal Carnot cycle is not used as a criterion for assessing the efficiency of cycles of power plants with highly variable thermophysical properties of the working fluid. It is also shown that the thermal efficiency of the regenerative cycle with the decrease of the working body when entering the turbine is always lower than the thermal efficiency of the equivalent non-equilibrium Carnot cycle with a change in the specific heat of the working fluid, which corresponds to the second law of thermodynamics. It is shown that the Brighton regenerative cycle with a decrease in the working body before the turbine can be represented as a conditional cycle with a higher maximum temperature of the cycle, which, depending on the mass content of the moisture content of the working body, can in 1,2 ... 2,5 times exceed the actual maximum temperature cycle, which determines the high values ​​of its thermal efficiency.

scholarly journals Performance comparison of the solar-driven supercritical organic Rankine cycle coupled with the vapour-compression refrigeration cycle

Clean Energy ◽  
2021 ◽  
Vol 5 (3) ◽  
pp. 476-491
Author(s):  
Yunis Khan ◽  
Radhey Shyam Mishra
Keyword(s):  
Thermal Efficiency ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Coefficient Of Performance ◽  
Solar Irradiation ◽  
Working Fluid ◽  
Refrigeration Cycle ◽  
Exergy Destruction ◽  
Cogeneration System ◽  
Vapour Compression

Abstract In this study, a parametric analysis was performed of a supercritical organic Rankine cycle driven by solar parabolic trough collectors (PTCs) coupled with a vapour-compression refrigeration cycle simultaneously for cooling and power production. Thermal efficiency, exergy efficiency, exergy destruction and the coefficient of performance of the cogeneration system were considered to be performance parameters. A computer program was developed in engineering equation-solver software for analysis. Influences of the PTC design parameters (solar irradiation, solar-beam incidence angle and velocity of the heat-transfer fluid in the absorber tube), turbine inlet pressure, condenser and evaporator temperature on system performance were discussed. Furthermore, the performance of the cogeneration system was also compared with and without PTCs. It was concluded that it was necessary to design the PTCs carefully in order to achieve better cogeneration performance. The highest values of exergy efficiency, thermal efficiency and exergy destruction of the cogeneration system were 92.9%, 51.13% and 1437 kW, respectively, at 0.95 kW/m2 of solar irradiation based on working fluid R227ea, but the highest coefficient of performance was found to be 2.278 on the basis of working fluid R134a. It was also obtained from the results that PTCs accounted for 76.32% of the total exergy destruction of the overall system and the cogeneration system performed well without considering solar performance.

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.

Producing the World’s Finest Heat Engine

2016 ◽  
Author(s):  
Bernard L. Koff
Keyword(s):  
Power Generation ◽  
Gas Turbine ◽  
Power Efficiency ◽  
Heat Engine ◽  
Specific Power ◽  
Technology Evolution ◽  
Design And Manufacturing ◽  
High Specific Power ◽  
Marine Applications ◽  
Aircraft Propulsion

The gas turbine is the World’s most complex and versatile heat engine used worldwide for aircraft propulsion, marine applications and power generation. The technology evolution developed since Whittle’s first successful demonstration in 1937 is an exciting story of design innovation using many engineering disciplines. This paper, from a designer’s perspective, covers key design and manufacturing innovations that were developed to produce today’s engines with high specific power, efficiency and durability.

Analysis and Optimization of an Ammonia Based Transcritical Rankine Cycle for Power Generation

2008 ◽  
Author(s):  
Jahar Sarkar ◽  
Souvik Bhattacharyya
Keyword(s):  
Power Generation ◽  
Low Temperature ◽  
Thermal Efficiency ◽  
Rankine Cycle ◽  
Working Fluid ◽  
Heat Sources ◽  
High Side ◽  
Water Based ◽  
Temperature Heat ◽  
Transcritical Rankine Cycle

This study presents the potential of ammonia as a working fluid in transcritical Rankine cycle for power generation using both high and low temperature heat sources. Higher heat capacity value and superior heat transfer properties of ammonia compared to water are the motivating factors behind its use as a working fluid. A thermodynamic analysis for the ammonia based transcritical Rankine cycle and its comparison with the water based Rankine cycle is presented. Analyses with several cycle modifications are also presented to study the thermal efficiency augmentation. It is observed that an optimum high side pressure exists for near critical operation. In case of low temperature heat sources such as solar energy or waste heat, where water based systems are not suitable, ammonia based Rankine cycle is applicable with attractive thermal efficiency, although cycle modification is not possible. The results with high temperature heat source such as boiler or nuclear reactor, where the turbine outlet is in superheated zone, show that simple ammonia systems yield lower efficiency than water, although a recompression cycle with regenerative heat exchangers exhibits higher efficiency than water. Significant thermal efficiency improvement can be achieved by increasing the high side cycle pressure. Recompression Rankine cycle can be a potential alternative with proper design measures taken to avoid toxicity and flammability.

Optimization of 200 to 3000 W Gas Turbine MEMS Arrangement

2009 ◽  
Author(s):  
A. V. Sudarev ◽  
A. A. Suryaninov ◽  
B. A. Bazarov ◽  
V. S. Ten ◽  
L. Lelait ◽  
...  
Keyword(s):  
Power Generation ◽  
Gas Turbine ◽  
Power Efficiency ◽  
High Speed ◽  
Three Dimensional ◽  
Gas Turbine Engine ◽  
Specific Power ◽  
Environmental Friendliness ◽  
Turbine Engine ◽  
Electric Generator

The persistent increase in demand for compact efficient power generation plants for the decentralized power supply systems applications, pipelines, micro air vehicles, electronics, etc stipulates developments of independent micro sources. Application of the micro gas turbine engine (μGTE) as an electric generator drive allows a sharp increase in the specific energy and operation independence, elimination of ambient temperature effects on the specific power, environmental friendliness improvement. However, GTE miniaturization causes its efficiency decreasing. Hence, there is a need in improvement of the micro engine of 200–3,000W power efficiency. The approach proposed is the ceramic tunnel turbomachine concept for the regenerative μGTE (MEMS-based) application [1, 2, 3] with conventional annular systems of vanes replaced with three-dimensional conic channels. The μGTE turbocompressor unit design is dependent on the conceptual arrangement approach i.e. a manner the gas turbine engine micro turbocompressor (μTC) is joined with the driven micro electric generator (μEG) assumes a great importance. Two conceptually opposite μTC concepts over the turbocompressor unit are considered: - the μTC rotor connected with the μEG rotor by an electromagnet coupling; - appropriate elements of μEG built into the rotor and stator sections of μTC. Examination of the essentially different concepts of the μEG - micro turbocompressor (μTC) arrangement demonstrated that an independent power generation, high temperature, and high speed μGTE reliable operating can be ensured by different arrangements, e.g. with the rotor and stator sections of the electric generator placed between the appropriate turbine and compressor stage devices. In this case it is easier, compared to some other approaches, to evade an unpropitious effect on the μTC rotor strength characteristics (total stress level, critical velocities within the speed operation range, radial and axial deformations, etc) imposed by sizes and mass of the contact-free electromagnet couplings elements. This inference ensues, also, from the studies conducted [4, 5].

The Basic Thermodynamics of Turbine Cooling

2000 ◽  
Vol 123 (3) ◽  
pp. 583-592 ◽  
Author(s):  
J. H. Horlock
Keyword(s):  
Gas Turbine ◽  
Thermal Efficiency ◽  
Combustion Temperature ◽  
Plant Performance ◽  
Maximum Temperature ◽  
Working Fluid ◽  
Turbine Plant ◽  
Cooling Flows ◽  
Turbine Cooling ◽  
Gas Turbine Plant

Analyses of gas turbine plant performance, including the effects of turbine cooling, are presented. The thermal efficiencies are determined theoretically, assuming air standard (a/s) cycles, and the reductions in efficiency due to cooling are established; it is shown that these are small, unless large cooling flows are required. The theoretical estimates of efficiency reduction are compared with calculations, assuming that real gases form the working fluid in the gas turbine cycles. It is shown from a/s analysis that there are diminishing returns on efficiency as combustion temperature is increased; for real gases there appears to be a limit on this maximum temperature for maximum thermal efficiency.

scholarly journals Experimental and Numerical Study of Thermal Performance for Flat Plate Solar Water Heater in Najaf

2021 ◽  
Vol 877 (1) ◽  
pp. 012042
Author(s):  
Mohammed J Alghurabe ◽  
Dhafer M Al-Shamkhee ◽  
Assaad A Alsahlani
Keyword(s):  
Flat Plate ◽  
Thermal Performance ◽  
Numerical Study ◽  
Climatic Conditions ◽  
Economic Feasibility ◽  
Engine Oil ◽  
Working Fluid ◽  
Water Mixture ◽  
Working Fluids ◽  
Good Convergence

Abstract This work presented the numerical and experimental study of the thermal performance of a flat plate collector (FPC). This study focuses on analyzing the performance of (FPC) in the climatic conditions of Najaf and calculating the thermal energy produced by the collector for domestic use, which reduces the electricity consumption that Iraq is witnessing a severe shortage in its supply. Also, various working fluids (water, oil engine, ethylene glycol-water mixture) were tested to determine the best working fluid that improves the collector’s efficiency. The experiments were performed in Najaf, Iraq (32° 2’ N / 44° 18’ E) on January 9, 2019. The simulation study of the (FPC) is performed by COMSOL Multiphasic 5.3 software. The numerical results were validated with experimental results and there was good convergence between them. The results showed that the average daily efficiency of the solar collector (FPC) was 37.17%, and the highest outlet water temperature of the collector was 57.1Co. The collector achieved a useful cumulative useful heat during the day of about 3.3557 MW, this contributes to reducing the use of electricity and achieving the required economic feasibility of use (FPC). Finally, the engine oil gave better results in improving efficiency compared to other working fluids.

Modeling and Testing a Cold Plate

2006 ◽  
Author(s):  
Bryan R. Wilcox ◽  
Donald W. Mueller ◽  
Hosni I. Abu-Mulaweh
Keyword(s):  
Numerical Model ◽  
Thermal Resistance ◽  
Cover Plate ◽  
Maximum Temperature ◽  
Working Fluid ◽  
Water Mixture ◽  
Heat Flow Rate ◽  
Cold Plate ◽  
Maximum Temperature Difference ◽  
Total Thermal Resistance

The objectives of this work were to build and test a liquidcooled cold plate, and then to develop a numerical model to describe the thermal characteristics of the cold plate. An important parameter of interest was the total thermal resistance of the cold plate which is defined as the maximum temperature difference divided by the net heat flow rate. A cold plate was constructed by machining nine parallel, rectangular channels into an aluminum base (1.65 cm × 7.6 cm × 40 cm) upon which an aluminum cover plate was then welded. Twelve thermocouples were used to measure the temperature of the plate (surface and fin tip) and the circulating fluid at the inlet, outlet, and mid-plane. The working fluid was a 50/50 ethylene glycol-water mixture. Three heater blocks were mounted to the cold plate, and the assembly was insulated so that heat loss to the surroundings was minimized. Four runs were performed with flow rates ranging from 56 g/s to 95 g/s, and after steady-state conditions were reached the temperatures were recorded. Using these temperature measurements, the total thermal resistance was calculated. The thermal resistance of the cold plate was also calculated using a one-dimensional numerical model; agreement between the experimental measurements and model predictions is good. The methods described and results presented in this paper are useful to applied thermal engineers.

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