scholarly journals A Perspective Evolution Methodology of Energy Management in a Subcritical Regenerative Organic Rankine Cycles Operate at Two Temperature Levels

2021 ◽  
Vol 8 (1) ◽  
pp. 9-26
Author(s):  
Ali H. Tarrad
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Energy Management ◽  
Thermal Efficiency ◽  
Energy Recovery ◽  
Operating Conditions ◽  
Temperature Cycle ◽  
Evaporation And Condensation ◽  
Organic Rankine Cycles ◽  
Temperature Levels

The waste energy recovery and management philosophy represent a great challenge for scientists. This article outlines a scheme to utilize two different source temperature levels in the range of (160–200) °C. Two regenerative organic Rankine cycles (RORC) were implemented to construct a compound regenerative organic Rankine cycle (CRORC) to improve the energy management of the sources. The method of energy management for these cycles was accomplished by extracting a certain amount of energy from the high-temperature cycle and rejecting it to the working fluid in an economizer at the low-temperature level. R-123 was circulated in the high-temperature cycle due to its high critical temperature at evaporation and condensation temperatures of 150 °C and 50 °C respectively. R-123, R-245fa, R-1233zd-E, and the hydrocarbon R-600a were used as working fluids for the low-temperature cycle at evaporation and condensation temperatures of 130 °C and 35 °C respectively. This technique showed that the first law of thermodynamics efficiency was augmented by (3–5)% for the low-temperature mini-cycle of the (CRORC). The energy consumption at the low-temperature cycle was also reduced by (3–5)%. The latter reduction range accounts for 2% for the total extracted energy for the independent system where both high-temperature and low-temperature cycles were utilized separately. The data showed that increasing the superheat degree from 10 °C to 20°C has enhanced the thermal efficiency of the compound (CRORC) system by (2–4)%. The (CRORC) system of R-123/R600a, R-123/R-123, and R-123/R-245fa fluid pairs exhibited higher thermal efficiency than that of R-123/R-1233zd-E pair by (4.5–6)%, (4–6)% and (3–4)% respectively. The net thermal efficiency of the compound (CRORC) system fell in the range (12–13)% and the low-temperature mini-cycle of the (CRORC) system had a range of (12–14)% for all of the examined operating conditions. Keywords: compound cycle, regenerative, energy management, energy recovery

scholarly journals A Waste Energy Recovery Management for Electricity Generation from Two Temperature Grades of Energy Sources in Subcritical Organic Rankine Systems

2021 ◽  
Vol 8 (3) ◽  
pp. 217-236
Author(s):  
Ali H. Tarrad
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Energy Management ◽  
Thermal Efficiency ◽  
Energy Recovery ◽  
Temperature Cycle ◽  
Compound System ◽  
Temperature Level ◽  
Evaporation And Condensation ◽  
Waste Energy

Waste energy represents one of the most critical issues for the economic utilization and management of energy in modern industrial fields. This article outlines a scheme to utilize two different source temperature levels within the envelope of higher than 200 °C zones. Two regenerative organic Rankine cycles (RORC) were implemented to construct a compound regenerative organic Rankine cycle (CRORC) to improve the energy management of the sources. These two mini-cycles were integrated throughout an intermediate economizer circuit to extract a certain amount of energy from the high-temperature level mini-cycle. R-123 was circulated in the high-temperature cycle due to its high critical temperature at evaporation and condensation temperatures of 160 °C and 50 °C, respectively. R-123, R-21, and hydrocarbon R-600 were used as working fluids for the low-temperature cycle at evaporation and condensation temperatures of 130 °C and 35 °C, respectively. The R-123 fluid in the high-temperature mini-cycle was superheated to 170-240 °C, whereas the fluid in the low-temperature level was superheated to 180 °C. The results showed that the independent system (IRORC) requires more energy recovery than the compound system by a maximum of 2% to achieve the same net power output. This corresponds to the enhancement of 2% for the system net thermal efficiency of the compound (CRORC) system compared to the independent (IRORC) one. The compound (CRORC) system revealed a net thermal efficiency in the range of 14% and 15.6% for the test conditions. The mini-cycle net thermal efficiency of the low-temperature in the compound system was enhanced by a range of 2.5-5% compared to that of the independent arrangement. R-123/R-123 and R-123/R-21 systems exhibited higher net thermal efficiencies than the R-123/R-600 one by 3% and 2%, respectively. Increasing the superheat degree of the high-temperature mini-cycle from 10 °C to 80 °C for the compound system has improved the thermal efficiency by 7.6-7.9% for the examined fluid pairs and operating conditions. Keywords: compound cycle, regenerative, energy management, energy recovery, organic fluids

scholarly journals Thermal Energy Recovery from a Grid Connected Photovoltaic-Thermal (PVT) System Using Water as Working Fluid

2018 ◽  
Vol 7 (4.36) ◽  
pp. 389
Author(s):  
Alhassan Salami Tijani ◽  
Amer Farhan Bin Md Tahir ◽  
Jeeventh Kubenthiran ◽  
Baljit Singh Bhathal Singh
Keyword(s):  
System Design ◽  
Thermal Efficiency ◽  
Energy Recovery ◽  
Operating Conditions ◽  
Design Parameters ◽  
Working Fluid ◽  
Geometrical Configuration ◽  
Ansys Fluent ◽  
Design Concepts ◽  
Pressure Distributions

A Photovoltaic Thermal collector (PVT) is a combination of Photovoltaic (PV) and Thermal (T) collector. Many studies have tried to improve the electrical efficiency and thermal efficiency of this PVT system. The efficiency is influenced by many system design parameters and operating conditions such as the absorber temperature, velocity and pressure distributions. In this study, two new design concepts of absorber configuration of thermal collector have been investigated. This study also provides an important opportunity to advance the understanding of the effect of different geometrical configuration on the performance of the absorber.  Simulations were performed using ANSYS FLUENT 16.0 for both absorbers to determine the best absorber design that gives the highest thermal efficiency. Based on the simulations performed, perpendicular serpentine absorber proved to be the best design with the higher thermal efficiency of 56.45%.    

Study on the Mechanical Property of Nomex Fiber in Different Temperature

2014 ◽  
Vol 887-888 ◽  
pp. 895-898
Author(s):  
Gen Yang Cao ◽  
Xing Fang Xiao ◽  
Wei Lin Xu
Keyword(s):  
Mechanical Property ◽  
High Temperature ◽  
Low Temperature ◽  
Temperature Cycle ◽  
High Tech ◽  
New Materials ◽  
Breaking Elongation ◽  
Temperature Conditions ◽  
World Today ◽  
The World

Nomex (Aramid 1313) is the best high temperature resistant high-tech new materials in the world today. In this paper, Nomex was treated in the experiment of high temperature, low temperature, high and low temperature conditions. The results show that the high temperature affects the strength and breaking elongation for nomex fiber. Low temperature and high & low temperature cycle does not affect much on the strength and breaking elongation.

Stress Intensity Factor of Thermal Fatigue Crack in High Temperature

2012 ◽  
Vol 581-582 ◽  
pp. 677-680
Author(s):  
Ming Yan ◽  
Hao Chuan Li ◽  
Lin Li
Keyword(s):  
Stress Intensity Factor ◽  
Fatigue Crack ◽  
High Temperature ◽  
Stress Intensity ◽  
Low Temperature ◽  
Intensity Factor ◽  
Thermal Fatigue ◽  
Kinematic Hardening ◽  
Temperature Cycle ◽  
Thermal Fatigue Crack

Stress intensity factor of thermal fatigue crack was calculated within one cycle by using finite element method in consideration of the multi-linear kinematic hardening characteristic of a material. The affection of loading sequence to stress intensity factor was studied under circularly variational temperature by comparing to that in one cycle. The low temperature cycle can not affect the stress intensity factor of latter cycles with high temperature; but high temperature cycle can affect the stress intensity factor of latter cycles with low temperature, and make it be equal to that of the high temperature cycle.

scholarly journals Experimental investigation of the ecological hybrid refrigeration cycle

2014 ◽  
Vol 35 (3) ◽  
pp. 145-154
Author(s):  
Piotr Cyklis ◽  
Ryszard Kantor ◽  
Tomasz Ryncarz ◽  
Bogusław Górski ◽  
Roman Duda
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Heat Source ◽  
Waste Heat ◽  
Temperature Limit ◽  
Working Fluid ◽  
Temperature Cycle ◽  
Compression System ◽  
High Temperature Limit ◽  
University Of Technology

Abstract The requirements for environmentally friendly refrigerants promote application of CO2 and water as working fluids. However there are two problems related to that, namely high temperature limit for CO2 in condenser due to the low critical temperature, and low temperature limit for water being the result of high triple point temperature. This can be avoided by application of the hybrid adsorption-compression system, where water is the working fluid in the adsorption high temperature cycle used to cool down the CO2 compression cycle condenser. The adsorption process is powered with a low temperature renewable heat source as solar collectors or other waste heat source. The refrigeration system integrating adsorption and compression system has been designed and constructed in the Laboratory of Thermodynamics and Thermal Machine Measurements of Cracow University of Technology. The heat source for adsorption system consists of 16 tube tulbular collectors. The CO2 compression low temperature cycle is based on two parallel compressors with frequency inverter. Energy efficiency and TEWI of this hybrid system is quite promising in comparison with the compression only systems.

Design of a High Temperature EMI Input Filter for a 2 kW HVDC-Fed Inverter

2011 ◽  
Vol 8 (1) ◽  
pp. 23-30 ◽  
Author(s):  
Rémi Robutel ◽  
Christian Martin ◽  
Hervé Morel ◽  
Cyril Buttay ◽  
Nicolas Gazel ◽  
...  
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Temperature Dependence ◽  
Design Procedure ◽  
Operating Conditions ◽  
Input Filter

In this article, a high temperature EMI input filter for a SiC JFET inverter is designed and tested in operating conditions at 200°C. Inverter EMI issues, design procedure, and characterizations of selected components are presented in detail. The feasibility based on industrially available materials and components is demonstrated with a low temperature dependence of the EMI spectrum.

Design of High Temperature EMI Input Filter for a 2 kW HVDC-fed Inverter

2010 ◽  
Vol 2010 (HITEC) ◽  
pp. 000236-000243 ◽  
Author(s):  
Remi Robutel ◽  
Christian Martin ◽  
Herve Morel ◽  
Cyril Buttay ◽  
Dominique Bergogne ◽  
...  
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Temperature Dependence ◽  
Design Procedure ◽  
Operating Conditions ◽  
Input Filter

In this paper, a high temperature EMI input filter for a SiC JFET inverter is designed and tested in operating conditions at 200°C. Inverter EMI issues, design procedure and characterizations of selected components are presented in details. The feasability based on industrially available materials and components is demonstrated with a low temperature dependence of EMI Spectrum.

Determination of Cooling Parameters for a High-Speed, True-Scale, Metallic Turbine Vane

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Marc D. Polanka ◽  
James L. Rutledge ◽  
David G. Bogard ◽  
Richard J. Anthony
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Low Temperature ◽  
Surface Temperature ◽  
Thermal Barrier Coating ◽  
Biot Number ◽  
Operating Conditions ◽  
Thermal Barrier ◽  
Barrier Coating ◽  
Overall Effectiveness

Facilities such as the Turbine Research Facility (TRF) at the Air Force Research Laboratory have been acquiring uncooled heat transfer measurements on full-scale metallic airfoils for several years. The addition of cooling flow to this type of facility has provided new capabilities and new challenges. Two primary challenges for cooled rotating hardware are that the true local film temperature is unknown, and cooled thin-walled metallic airfoils prohibit semi-infinite heat conduction calculation. Extracting true local adiabatic effectiveness and the heat transfer coefficient from measurements of surface temperature and surface heat transfer is therefore difficult. In contrast, another cooling parameter, the overall effectiveness (ϕ), is readily obtained from the measurements of surface temperature, internal coolant temperature, and mainstream temperature. The overall effectiveness is a normalized measure of surface temperatures expected for actual operating conditions and is thus an important parameter that drives the life expectancy of a turbine component. Another issue is that scaling ϕ from experimental conditions to engine conditions is dependent on the heat transfer through the part. It has been well-established that the Biot number must be matched for the experimentally measured ϕ to match ϕ at engine conditions. However, the thermal conductivity of both the metal blade and the thermal barrier coating changes substantially from low-temperature to high-temperature engine conditions and usually not in the same proportion. This paper describes a novel method of replicating the correct thermal behavior of the thermal barrier coating (TBC) relative to the metal turbine while obtaining surface temperature measurements and heat fluxes. Furthermore, this paper describes how the ϕ value obtained at the low-temperature conditions can be adjusted to predict ϕ at high-temperature engine conditions when it is impossible to match the Biot number perfectly.

Report of the Automobile Research Committee on the Performance of a Converted Petrol Engine with Different Producer Fuels

1943 ◽  
Vol 37 (2) ◽  
pp. 155-194 ◽  
Author(s):  
J. Spiers ◽  
E. Giffen
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Hydrogen Content ◽  
Power Output ◽  
Average Power ◽  
Operating Conditions ◽  
Petrol Engine ◽  
Water Addition ◽  
Research Committee ◽  
The Government

A six-litre petrol engine has been tested, using six different fuels, in the Government Emergency Gas Producer. The fuels used comprised anthracite, activated anthracite, low-temperature coke, high-temperature (Birmingham) coke, activated high-temperature coke, and charcoal. Starting qualities, variations in power and gas quality during the run, and flexibility were investigated. In addition, some miscellaneous information relating to operating conditions with the various fuels was obtained. Easiest starting was obtained with charcoal, though low-temperature coke was very little inferior in this respect. Anthracite was somewhat variable, but usually good in starting qualities, and activated anthracite showed some improvement in consistency. High-temperature coke, whether activated or not, was poor in starting qualities, though some improvement was obtained with the use of preheated air and water fed to the tuyère, and it is of advantage to add the water as soon after lighting as possible. Anthracite, whether activated or not, showed serious deterioration in starting qualities when used fuel (“bottoms”) was mixed with new fuel, and this deterioration was also shown, though to a less extent, with low-temperature coke. High-temperature coke showed no change in starting quality after use. In general, the C.A.B. values gave a good indication of the relative starting qualities of the fuels. Under dry-blast conditions the average power given by 100 per cent new fuel was greatest with anthracite (whether activated or not) and lowest with high-temperature coke, low-temperature coke and charcoal occupying an intermediate position. The use of an air preheater and water addition to the producer tuyère brought the power output with high-temperature coke (both activated and unactivated) up to the level of that given by charcoal and low-temperature coke, whereas admixture of used fuel resulted in appreciable reduction in power with both anthracite and low-temperature coke, the high-temperature cokes were not affected. Thus, in the 100 per cent used condition, high-temperature coke (with wet blast) gave power equal to that given by anthracite, and superior to that given by low-temperature coke. The use of air preheating and water addition had little effect on power output with new anthracite, but gave appreciable improvement with 100 per cent used fuel. Charcoal and low-temperature coke displayed the best flexibility of any of the fuels tested, while anthracite was the worst fuel in this respect. High-temperature cokes with wet blast were superior to anthracite in this quality, and activation appears to be an advantage. Some improvement in the performance of anthracite as regards flexibility was obtained by the use of wet blast, though it remained inferior to any other fuel. Hydrogen content varied widely throughout the producer run with both anthracite and low-temperature coke, and, in practice, it would be difficult to obtain optimum ignition timing under all conditions with these fuels. The hydrogen content given by high-temperature cokes and charcoal, on the other hand, remained fairly constant through the run, and such fuels may show to advantage under road conditions, owing to the ease with which optimum timing may be obtained. The rate of fuel consumption in lb. per hour was very similar with all fuels, including petrol, at the same engine speed, the only exceptions to this being charcoal, which gave high rates, and the high-temperature cokes, if account is taken of the water necessarily used under wet blast conditions. No clinker trouble was experienced with any of the fuels used, but whereas low-temperature coke caused choking of the filters at frequent intervals, the high-temperature cokes used gave no trouble in this respect. Charcoal, on account of its high moisture content, gave wet filter conditions, rendering the sisal difficult to clean. Cylinder wear was not excessive with any of the fuels.

Experimental Study on Two-Stage Cascade Low Temperature Pre-Cooling Equipment

2010 ◽  
Vol 42 ◽  
pp. 322-325
Author(s):  
Xiu Fang Liu ◽  
Fa Hui Wang ◽  
Fan Mao Meng
Keyword(s):  
Experimental Study ◽  
High Temperature ◽  
Low Temperature ◽  
Cooling Capacity ◽  
Temperature Cycle ◽  
Test Bed ◽  
Two Stage ◽  
Overload Protection ◽  
Set Up ◽  
Two Stages

A two-stage cascade pre-cooling test bed was designed and set up to develop a -30°C /-60°C pre-cooling equipment. An internal heater exchanger and a condenser were set in low-temperature cycle. Theoretically the two stages can work stably at setting temperature and the low-temperature cycle can operate independently with aided starting of the high-temperature cycle. The experimental results indicate that the test bed can provide cooling capacity steadily at -46°C and -100°C respectively and the low-temperature cycle cannot operate alone for compressor overload protection. Based on the analysis, the possible reasons and detailed suggestions were put forward.

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