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The supply of waste heat represents a huge and freely available amount of energy that make it a key target for energy conversion technologies, notwithstanding the small thermodynamic efficiency to be expected because of the limited working temperature difference.
The typical “Green Computing” case studies are discussed. The deployments scenarios based on waste heat modeling and recycling are discussed. The following simplified models to solution of the Boltzmann thermodynamic equations are examined. Taken into account the presented models the approximated estimations regarding to PUE within the computing centers of the cloud and HPC providers can be met.
The regenerative cycle system based on absorption heat pump heats feed water through steam driving absorption heat pump by absorbing the low temperature waste heat of circulating cooling water, the system can reduce the circulating water temperature and low pressure heater extraction, and further to improve the thermal efficiency of unit. By studying on supercritical 600MW unit according to equivalent...
Rational utilization of waste heat is one of the important measures to improve the energy utilization efficiency and save energy, and the crucial way of waste heat utilization is thermal vapor compression (TVC). The calculation method of efficiency evaluation of waste heat recovery by TVC is presented, which can be applied to predict the effect of energy saving when the parameters of waste heat deviate...
This paper presents a review of the status of power generation with nonaqueous working fluids from low-temperature thermal resource, the features, equipment composition and working processed as well as comparison of two main types of thermodynamic cycles which are Organic Rankine Cycle(ORC) and Kalina Cycle and nonaqueous working fluids including their classification and filter criteria for thermodynamic...
Four types of double-stage Water-Lithium Bromide absorption heat pump systems were introduced to recover waste heat of about 40°C. Thermodynamic and heat transfer numerical simulation was carried out to predict the performance of these absorption heat pumps. The effects of the driving heat source (steam) input pressure, the waste heat outlet temperature, and the hot water inlet temperature on the...
Sewage source heat pump system plays a significant role in energy-saving and environmental protection which can be divided into direct and indirect system. For the shortcoming of research on the direct one, some anti-scaling technology and the heat exchangers to remove the soft dirt are introduced. Based on the exergy method, an analysis is given of energy efficiency in the direct sewage source heat...
To reduce the energy consumption of evaporation process in alumina refinery, thermal and exergy analysis were applied to the four-effect evaporators and three-stage flashes evaporation system. Result indicates that the thermal efficiency of the evaporation system is only 15.22%. The thermal efficiencies of all links are high except that of the evaporator of effect IV, which is only 6.91%. The heat...
This paper firstly introduces the principles of Refrigerant Phase-Change Stirling-Cycle solar power towers This heat engines use solar reservoir. When the refrigerant in an engine cylinder absorbs heat from high-temperature heat sources, refrigerant is transformed from liquid to gas and the volume of the refrigerant expands to drive the piston apply work. When the refrigerant releases heat to low-temperature...
A comparative study of different Cases (A1, A2, B, C1, C2, D) of regenerator calculating methodology has been carried out for use in subcritical and transcritical organic Rankine cycles(ORCs) driven by low-temperature heat sources. The applicable ranges and conditions as well as influences on thermodynamic performances of different Cases have been analyzed. Results show that, for subcritical ORCs...
In this study, the first and the second law of thermodynamics are used to assess the heat pump system performance utilizing sewage source (SSHP). The system was designed, constructed and tested in Harbin Engineering University. Energy and exergy analysis methods were used to evaluate the system performance, exergy loss of each component and total exergy loss of all the system components. The results...
The coefficient of performance (COP) is one efficient important evaluating indicator in the urban sewage heat pump system. Based on the engineering thermodynamics principle, the heating operating performance of direct and indirect systems have been analyzed and compared. The results indicate that the actual COP of direct sewage source heat pump system is higher approximately 0.3 than that of indirect...
It is an important measure to recovery and utilize the residual heat resource of sintering-cooling process in cogeneration system for modern iron and steel enterprises nowadays. In the paper, the key problems and causes of recovery and utilization of sintering residual/waste heat were analyzed firstly, and then the method and technique of "grade recovery and cascade utilization(GRUC)" was...
A detailed energy and exergy analysis of a low-temperature geothermal organic Rankine cycle is presented, screening the appropriate working fluids for specific heat source conditions. The results have been calculated with pinch point analysis approach for fixed temperature and mass flow rate of the heat source, fixed pinch points in evaporator and condenser and fixed condensing and sink temperatures...
Mechanical energy is produced when heat is carried upward by convection in the atmosphere. An atmospheric vortex engine (AVE) uses an artificially created anchored tornado like vortex to capture the mechanical energy produced during upward heat convection. The vortex is created by admitting warm or humid air tangentially into the base of a circular wall. The heat source can be solar energy, warm sea...
Options to increase waste heat recovery (WHR) power generation in clinker kilns are discussed. WHRS via kiln production process heat re-integration and AQC and SP WHR boilers components integration to maximize WHR rate is discussed. WHR boiler exhaust gas temperature could be greatly reduced via a new dual pressure system by which the WHR rate could be improved. Finally, heat from tertiary air as...
In this paper, the exothermic distribution of fuel was studied detailedly through conducting thermal equilibrium experiment when the vehicle gasoline engine was at different working conditions. Considering the characteristic of the exhaust temperature of the vehicle gasoline engine, the Organic Rankine Cycle (ORC) was adopted for the exhaust recovery. The thermodynamic parameter and thermodynamic...
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