Journal articles: 'Heat output from the switchgear'

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Yu, Hong, Maoyong Cao, Tanbo Zhu, and Fanming Liu. "Study of Heating Device for Sulfur Hexafluoride Gasification." Sensor Letters 18, no. 2 (February 1, 2020): 157–63. http://dx.doi.org/10.1166/sl.2020.4201.

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Sulfur hexafluoride (SF6) gas has been used to gas-insulated switchgear (GIS) because of its insulation properties and extinguishing characteristics. The processing of liquid sulfur hexafluoride from cylinders into GIS is endothermic. The processing gas inflation always leads to decrease SF6 gas inflation speed due to the lack of heat supplement and the infiltrated moisture will stick on the GIS equipment, especially at the valve outlet. In the paper, a heater detection device for sulfur hexafluoride (SF6) steel cylinder is developed. The new heater device will monitor and display the specific temperature and humidity of the valve outlet instantaneously and then heat and dry the sulfur hexafluoride (SF6) steel cylinder with automatic and stability. Then it helps to speed up the sulfur hexafluoride gasification. Meanwhile, the whole device is portable in safety.

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Erickson, Donald C., Gopalakrishnan Anand, and Ellen Makar. "Absorption Refrigeration Cycle Turbine Inlet Conditioning." International Journal of Air-Conditioning and Refrigeration 23, no. 01 (March 2015): 1550003. http://dx.doi.org/10.1142/s2010132515500030.

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Ambient temperature markedly impacts combustion turbine performance. A typical aeroderivative turbine loses 25% of ISO capacity at 38°C ambient. There are two traditional options to mitigate that degradation: evaporative cooling and mechanical chilling. They boost turbine performance, but consume significant water and/or electric load. Also, the turbine requires separate anti-icing equipment for low ambient temperature operation (less than 4.4°C). This paper describes the Absorption Refrigeration Cycle Turbine Inlet Conditioning (ARCTIC) system that chills or heats the inlet air of a combustion turbine to maintain maximum turbine performance at all ambient temperatures. The ARCTIC unit is an ammonia–water absorption cycle that is powered by turbine exhaust heat. The design and performance of a 7034 kW (2000-ton) ARCTIC unit is presented. This ARCTIC achieved a new record for net power and heat rate from this model aeroderivative gas turbine in hot weather. It provides reliable and dispatchable hot day power at about half the cost of new plant. On a typical summer day (38°C dry bulb, 26°C wet bulb), ammonia refrigerant from the ARCTIC chills the inlet air to 8.9°C. The gas turbine power is increased from 40 to 51 MW. After allowing for the 230 kW electric parasitic load, the resulting net power is 2 MW more than the output of a comparable mechanically chilled gas turbine. As a result, the heat rate is also improved. On cold days the ARCTIC automatically switches to heating mode. The inlet air is heated by 11°C to eliminate inlet icing potential. Additional benefits include a lower exhaust temperature which is better for the Selective Catalytic Reduction (SCR) catalyst. The condensate recovered from the inlet-air chilling (up to 25 gallons per minute) can also be a valuable by-product. The ARCTIC system has a small cost premium relative to a mechanical chiller. However, when all the auxiliary functions are credited (anti-icing, tempering air, less switchgear, no 4160 volt service), the overall installed cost is comparable. The standout advantages are the increased hot weather power output, improved operating efficiency, and reduced maintenance, all obtained at minimal additional cost. Combined cycle and cogeneration configurations (both frame and aeroderivative) benefit even more from the ARCTIC due to the increased value of improved heat rate.

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Gao, Bao-Ming, Zheng-Yu Li, Jin-Wen Gao, Hao Liang, Zhi Yan, and Yi-Dan Hu. "The Simulation Study on Temperature Field Distribution of 220 kV Gas Insulated Switchgear." Journal of Nanoelectronics and Optoelectronics 16, no. 5 (May 1, 2021): 797–805. http://dx.doi.org/10.1166/jno.2021.2998.

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Under working conditions, the conductive rods in the GIS flow through the power frequency alternating current. Due to the coupling effect of the magnetic field and electric field between the metal aluminum shell and the conductive rod, induced eddy currents are generated in the metal shell of the GIS. The heat generated by the current heating effect of the GIS conductive rod and the eddy current loss of the metal casing will cause the temperature rise of GIS equipment. Due to the limited volume, the heat dissipation capacity of GIS is poor. Excessive temperature rise will accelerate the insulation aging of GIS equipment, and even damage its insulation, which will affect safe operation. In order to obtain the temperature change law of GIS, related influencing factors such as eddy current loss, skin effect, proximity effect, convective heat transfer of SF6 gas, and gravity of SF6 gas are comprehensively considered. The finite element analysis is used to research and discuss GIS magnetic field distribution, eddy current, temperature distribution and SF6 gas velocity. The initial value of the temperature of each part is set to 293.15 K (20 °C), and the temperature in the GIS is calculated to gradually decrease from the inside to the outside under the rated AC current of 3150 A. The temperature at the conductive rod position is the highest at 335.32 K, and the temperature at the housing position is the lowest at 294.65 K.

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Kapjor, Andrej, Peter Durcansky, and Martin Vantuch. "Effect of Heat Source Placement on Natural Convection from Cylindrical Surfaces." Energies 13, no. 17 (August 21, 2020): 4334. http://dx.doi.org/10.3390/en13174334.

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Placement of heat source can play a significant role in final heat output, or heat source effectivity. Because of this, there is a need to analyze thermal fields of the heat exchange system by natural convection, where the description by criterion equations is desired, as the net heat output from tubes can be quantified. Based on known theoretical models, numerical methods were adapted to calculate the heat output with natural air flow around tubes, where mathematical models were used to describe the heat transfer more precisely. After validation of heat transfer coefficients, the effect of wall and heat source placement was studied, and the Coanda effect was also observed. The heat source placement also has an effect at the boundary layer, which can change and therefore affect the overall heat transfer process. The optimal wall-to-cylinder distance for an array of horizontal cylinders near a wall was also expressed as a function of the Rayleigh number and number of cylinders in the array.

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Wu, Bisheng, Tianshou Ma, Guanhong Feng, Zuorong Chen, and Xi Zhang. "An Approximate Solution for Predicting the Heat Extraction and Preventing Heat Loss from a Closed-Loop Geothermal Reservoir." Geofluids 2017 (2017): 1–17. http://dx.doi.org/10.1155/2017/2041072.

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Approximate solutions are found for a mathematical model developed to predict the heat extraction from a closed-loop geothermal system which consists of two vertical wells (one for injection and the other for production) and one horizontal well which connects the two vertical wells. Based on the feature of slow heat conduction in rock formation, the fluid flow in the well is divided into three stages, that is, in the injection, horizontal, and production wells. The output temperature of each stage is regarded as the input of the next stage. The results from the present model are compared with those obtained from numerical simulator TOUGH2 and show first-order agreement with a temperature difference less than 4°C for the case where the fluid circulated for 2.74 years. In the end, a parametric study shows that (1) the injection rate plays dominant role in affecting the output performance, (2) higher injection temperature produces larger output temperature but decreases the total heat extracted given a specific time, (3) the output performance of geothermal reservoir is insensitive to fluid viscosity, and (4) there exists a critical point that indicates if the fluid releases heat into or absorbs heat from the surrounding formation.

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Dear, Keith. "Modelling Productivity Loss from Heat Stress." Atmosphere 9, no. 7 (July 22, 2018): 286. http://dx.doi.org/10.3390/atmos9070286.

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Workers exposed to high ambient temperatures, either indoors or out, work slower. The few studies that have measured this loss of productivity show a degree of consistency across widely varying settings. I develop a class of 5-parameter probability models that express productivity as a function of environmental heat and show how the method of fitting can be adapted according to the completeness of the data available. As well as modelling the mean output, it is important to also consider variation between workers, and the model presented here achieves this. The method is illustrated using three previously published datasets from different industries and work environments.

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Shibasaki, Manabu, Thad E. Wilson, Morten Bundgaard-Nielsen, Thomas Seifert, Niels H. Secher, and Craig G. Crandall. "Modelflow underestimates cardiac output in heat-stressed individuals." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 300, no. 2 (February 2011): R486—R491. http://dx.doi.org/10.1152/ajpregu.00505.2010.

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An estimation of cardiac output can be obtained from arterial pressure waveforms using the Modelflow method. However, whether the assumptions associated with Modelflow calculations are accurate during whole body heating is unknown. This project tested the hypothesis that cardiac output obtained via Modelflow accurately tracks thermodilution-derived cardiac outputs during whole body heat stress. Acute changes of cardiac output were accomplished via lower-body negative pressure (LBNP) during normothermic and heat-stressed conditions. In nine healthy normotensive subjects, arterial pressure was measured via brachial artery cannulation and the volume-clamp method of the Finometer. Cardiac output was estimated from both pressure waveforms using the Modeflow method. In normothermic conditions, cardiac outputs estimated via Modelflow (arterial cannulation: 6.1 ± 1.0 l/min; Finometer 6.3 ± 1.3 l/min) were similar with cardiac outputs measured by thermodilution (6.4 ± 0.8 l/min). The subsequent reduction in cardiac output during LBNP was also similar among these methods. Whole body heat stress elevated internal temperature from 36.6 ± 0.3 to 37.8 ± 0.4°C and increased cardiac output from 6.4 ± 0.8 to 10.9 ± 2.0 l/min when evaluated with thermodilution ( P < 0.001). However, the increase in cardiac output estimated from the Modelflow method for both arterial cannulation (2.3 ± 1.1 l/min) and Finometer (1.5 ± 1.2 l/min) was attenuated compared with thermodilution (4.5 ± 1.4 l/min, both P < 0.01). Finally, the reduction in cardiac output during LBNP while heat stressed was significantly attenuated for both Modelflow methods (cannulation: −1.8 ± 1.2 l/min, Finometer: −1.5 ± 0.9 l/min) compared with thermodilution (−3.8 ± 1.19 l/min). These results demonstrate that the Modelflow method, regardless of Finometer or direct arterial waveforms, underestimates cardiac output during heat stress and during subsequent reductions in cardiac output via LBNP.

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Orlov, Vladimir N., and R. Stephen Berry. "Power output from an irreversible heat engine with a nonuniform working fluid." Physical Review A 42, no. 12 (December 1, 1990): 7230–35. http://dx.doi.org/10.1103/physreva.42.7230.

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Elghool, Ali, Firdaus Basrawi, Hassan Ibrahim, Thamir K. Ibrahim, Shaharin A. Sulaiman, and M. Ishak. "Study on the Performance of a Thermo-Electric Generation Model with Two Different Materials of Heat Pipe-Heat Sink." MATEC Web of Conferences 225 (2018): 04009. http://dx.doi.org/10.1051/matecconf/201822504009.

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Heat sink lack of design is one reason that negatively affects the performance of thermoelectric modules. As compared to conventional cooling systems equipped with thermoelectric generators (TEG), heat pipe heat sink has various points of interest. Heat pipe heat sink is the most appropriate heat exchanger for medium temperature range under 300 °C. This paper demonstrates the effect of different materials of heat pipe-heat sink on the TEG performance. Two types of heat sinks were tested with TEG, one made from copper while the other from aluminium. The aim is to improve power output of TEG by an appropriate material of fins and metal block with heat pipes. The prototype was experimentally tested and the TEG cold side temperature, voltage and current were measured in both conditions, natural and forced convection. It was found that highest power output was achieved using copper heat sink in the case of forced convection, being 7.7 W whereas, lowest power output was obtained using aluminium heat sink in the case of natural convection, being 2.67 W. It is evident that copper heat sink is more effective than aluminium heat sink in terms of power output. However, both types of heat sink needs optimisation in terms of power output, cost and economic efficiency, while the results shown in this paper are just in terms of power output.

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Guyomar, Daniel, Gaël Sebald, Sébastien Pruvost, Mickaël Lallart, Akram Khodayari, and Claude Richard. "Energy Harvesting from Ambient Vibrations and Heat." Journal of Intelligent Material Systems and Structures 20, no. 5 (November 28, 2008): 609–24. http://dx.doi.org/10.1177/1045389x08096888.

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Increasing demand in mobile, autonomous devices has made the issue of energy harvesting a particular point of interest. Systems that can be powered up by a few hundreds of microwatts can feature their own energy extraction module, making them truly self-powered. This energy can be harvested from the close environment of the device. Particularly, piezoelectric conversion is one of the most investigated fields for ambient energy harvesting. Moreover, the extraction process can be optimized by proper treatment of the piezomaterial output voltage. This article proposes a detailed explanation of the real energy flow that lies behind several energy conversion techniques for piezoelectric energy scavenging. As well, the principles of energy harvesting using piezoelectric effect is extended to the pyroelectric effect, therefore allowing harvesting energy from temperature variation, which is one of the most common energy sources.

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Xinchun Li, Zhongwei Wang, and Zhongwei Wang. "Performance parameters analysis of an organic Rankine cycle for power generation from the heat of cooling scramjet." International Journal of Science and Research Archive 1, no. 2 (December 30, 2020): 009–21. http://dx.doi.org/10.30574/ijsra.2020.1.2.0032.

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An organic Rankine cycle (ORC) for power generation system is proposed for cooling scramjet. The heat which must be taken away by fuel coolant from cooling scramjet is converted to other forms of energy to decrease fuel coolant flow. A parametric study of an ORC power generation system has been performed. The multiplication ratio of fuel heat sink, the efficiency and output power of the system changing with the condenser outlet fuel coolant temperature are evaluated. The results show that the optimal condenser outlet fuel coolant temperature is 510K in a certain working condition, and the multiplication ratio of fuel heat sink is 0.0635, the efficiency of the system is 11.74% and the output power is 35.13kW. The effect of the cycle pressure ratio on the efficiency, output power and the multiplication ratio of fuel heat sink is also analyzed and it has a big significant influence. It is known through thermodynamic analyses that ORC power generation system for cooling scramjet would reduce the fuel coolant flow and give some output power for hypersonic vehicle.

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Li, Da, Qiang Sun, Ke Sun, Guodong Zhang, Shuzhan Bai, and Guoxiang Li. "Diesel engine waste heat recovery system comprehensive optimization based on system and heat exchanger simulation." Open Physics 19, no. 1 (January 1, 2021): 331–40. http://dx.doi.org/10.1515/phys-2021-0039.

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Abstract To further improve the thermal efficiency of diesel engines, a waste heat recovery system model utilizing organic Rankine cycle (ORC) is constructed and verified through system bench test and heat exchanger bench test. To recover waste heat from diesel engine exhaust, ethanol, cyclopentane, cyclohexane, R1233zd (E), and R245fa were selected for comparison. The quality of heat source, the quality of evaporator, the system output, and the system complicity were taken as variables for comparison. Analysis shows that for ORC systems without recuperator, ethanol system has the best system output of the five in a wide operation temper range, with the highest exergy efficiency of 24.1%, yet the exergy efficiency increase after the application of recuperator, 9.0%, is limited. For low temperature exhaust, cyclopentane system has the best performance with or without recuperator, and the cyclopentane system with recuperator has the best performance in terms of exergy efficiency, 27.6%, though complex heat exchangers are also required for high power output. The system output of the R1233zd system is better than the R245fa system, yet the advantage of low evaporate temperature can be better utilized for low quality waste heat recovery.

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Borsukiewicz-Gozdur, Aleksandra. "Influence of heat recuperation in ORC power plant on efficiency of waste heat utilization." Archives of Thermodynamics 31, no. 4 (October 1, 2010): 111–23. http://dx.doi.org/10.2478/v10173-010-0032-7.

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Influence of heat recuperation in ORC power plant on efficiency of waste heat utilization The present work is devoted to the problem of utilization of the waste heat contained in the exhaust gases having the temperature of 350 °C. Conversion of the waste heat into electricity using a power plant working with organic fluid cycles is considered. Three Organic Rankine Cycle (ORC) power plant solutions are analysed and compared: a solution with the basic, single thermodynamic conversion cycle, one with internal heat recuperation and one with external heat recuperation. It results from the analysis that it is the proper choice of the working fluid evaporation temperature that fundamentally affects the maximum of the ORC plant output power. Application of the internal heat recuperation in the plant basic cycle results in the output power increase of approx. 5%. Addition of the external heat recuperation to the plant basic cycle, in the form of a secondary supercritical ORC power cycle can rise the output power by approx. 2%.

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Li, Youyi, and Tianhao Tang. "Performance Analysis and Optimization of a Series Heat Exchangers Organic Rankine Cycle Utilizing Multi-Heat Sources from a Marine Diesel Engine." Entropy 23, no. 7 (July 16, 2021): 906. http://dx.doi.org/10.3390/e23070906.

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Organic Rankine Cycle (ORC) is an effective way to recycle waste heat sources of a marine diesel engine. The aim of the present paper is to analyze and optimize the thermoeconomic performance of a Series Heat Exchangers ORC (SHEORC) for recovering energy from jacket water, scavenge air, and exhaust gas. The three sources are combined into three groups of jacket water (JW)→exhaust gas (EG), scavenge air (SA)→exhaust gas, and jacket water→scavenge air→exhaust gas. The influence of fluid mass flow rate, evaporation pressure, and heat source recovery proportion on the thermal performance and economic performance of SHEORC was studied. A single-objective optimization with power output as the objective and multi-objective optimization with exergy efficiency and levelized cost of energy (LCOE) as the objectives are carried out. The analysis results show that in jacket water→exhaust gas and jacket water→scavenge air→exhaust gas source combination, there is an optimal heat recovery proportion through which the SHEORC could obtain the best performance. The optimization results showed that R245ca has the best performance in thermoeconomic performance in all three source combinations. With scavenge air→exhaust, the power output, exergy efficiency, and LCOE are 354.19 kW, 59.02%, and 0.1150 $/kWh, respectively. Integrating the jacket water into the SA→EG group would not increase the power output, but would decrease the LCOE.

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Ismail, Meor Mohd Rizal, Jazair Yahya Wira, Aminuddin Abu, and Mohd Azman Zainul Abidin. "Thermal Energy Harvesting From Automotive Waste Heat." Advanced Materials Research 516-517 (May 2012): 498–503. http://dx.doi.org/10.4028/www.scientific.net/amr.516-517.498.

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The objective of this study was to determine the best method for waste thermal energy recovery from internal combustion engine (ICE). There are several technologies that can be used to accomplish this objective such as turbocharger, combined turbines, Stirling engine, Seebeck effect and Rankine cycle. Two elements that need to be taken into consideration in order to choose the best technology for waste heat recovery system are the complexity of the system and the method to utilize waste heat energy from engine. After a reviewing some of past research work, it was determined that Rankine cycle appears to be one of the best technology to recover waste heat from ICE. Improved design in Rankine cycle configuration and selection of the highest evaporation enthalpy working fluid are said to be necessary. This study finally proposed that future related research should focus on recovering waste heat from the engine waste heat (engine block) only. This is predicted to give an additional power output of approximately 10%.

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Sharma, V. B., and S. C. Mullick. "Calculation of Hourly Output of a Solar Still." Journal of Solar Energy Engineering 115, no. 4 (November 1, 1993): 231–36. http://dx.doi.org/10.1115/1.2930055.

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An approximate method for calculation of the hourly output of a solar still over a 24-hour cycle has been studied. The hourly performance of a solar still is predicted given the values of the insolation, ambient temperature, wind heat-transfer coefficient, water depth, and the heat-transfer coefficient through base and sides. The proposed method does not require graphical constructions and does not assume constant heat-transfer coefficients as in the previous methods. The possibility of using the values of the heat-transfer coefficients for the preceding time interval in the heat balance equations is examined. In fact, two variants of the basic method of calculation are examined. The hourly rate of evaporation is obtained. The results are compared to those obtained by numerical solution of the complete set of heat balance equations. The errors from the approximate method in prediction of the 24-hour output are within ±1.5 percent of the values from the numerical solution using the heat balance equations. The range of variables covered is 5 to 15 cms in water depth, 0 to 3 W/m2K in a heat-transfer coefficient through base and sides, and 5 to 40 W/m2K in a wind heat-transfer coefficient.

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V, Venkatesh. "Extraction and Conversion of Exhaust Heat from Automobile Engine in to Electrical Energy." International Journal of Electrical and Electronics Research 6, no. 4 (October 10, 2018): 52–57. http://dx.doi.org/10.37391/ijeer.060401.

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Energy is vital for the progress of the nation and it has to be conserved in an efficient manner. Nowadays increasing worldwide problem is shortage of energy. In an Automobile out of the total heat supplied to the engine in the form of fuel, approximately 30 to 40 percent is converted into useful mechanical work and the remaining heat is expelled out as waste heat. This paper focus on the recovery and utilization of waste heat into useful electrical energy by using See back effect where in Thermoelectric Generators (TEG) are placed on the exhaust surface for converting heat directly into electrical energy. Thermoelectric generators are highly doped semiconductor solid state devices. The output voltage of the thermoelectric generator is given to a dc super lift converter circuit. The output of the super lift converter is used for battery charging.

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Khalil, Hesham, and Hamdy Hassan. "Enhancement thermoelectric generators output power from heat recovery of chimneys by using flaps." Journal of Power Sources 443 (December 2019): 227266. http://dx.doi.org/10.1016/j.jpowsour.2019.227266.

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Cekdin, Cekmas, Zainuddin Nawawi, and Muhammad Faizal. "An Effort to Reduce Voltage from DC to DC Converter with a Monolithic Circuit Based on IC LM 2596." Journal of Computational and Theoretical Nanoscience 16, no. 12 (December 1, 2019): 5162–65. http://dx.doi.org/10.1166/jctn.2019.8579.

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Step down regulator is a device that can reduce the more significant input voltage to a smaller output voltage. The output is stable and well regulated, although the voltage fluctuates in the recommended input voltage range. In the system using IC LM 2596, the input voltage is 40 Volt dc, and the output voltage is 30 Volt dc. The output current of 15 amperes is applied to charge a 100 Ampere hour (Ah) battery on an inverter system installed and integrated with other electronic devices. The step-down IC LM 2596 will be stable at the output current below 15 Ampere. It is especially stable at load currents from 13.2 Ampere to 14.57 Ampere. In order for the current not to shrink, a good cooling system must be designed to dispose of heat on the IC LM 2596. Because the high heat greatly affects the output current on the IC LM 2596.

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Budiyanto, Budiyanto, and Fadliondi Fadliondi. "The Improvement of Solar Cell Output Power Using Cooling and Reflection from Mirror." International Journal of Power Electronics and Drive Systems (IJPEDS) 8, no. 3 (September 1, 2017): 1320. http://dx.doi.org/10.11591/ijpeds.v8.i3.pp1320-1326.

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This paper explains the experimental investigation to improve the output power of solar cell using cooling and light reflection from mirrors. The results show that by adding mirror, the current and output power of solar cell increase but the open circuit voltage and maximum power voltage decrease due to heat. By adding cooling, the open circuit voltage and the maximum power voltage are improved, so the output power also increases.

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London˜o-Hurtado, Alejandro, and Alejandro Rivera-Alvarez. "Maximization of Exergy Output From Volumetric Absorption Solar Collectors." Journal of Solar Energy Engineering 125, no. 1 (January 27, 2003): 83–86. http://dx.doi.org/10.1115/1.1530197.

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A model has been developed to study the behavior of Volumetric Absorption Solar Collectors (VASC) and the influence of the design parameters on the performance of the collector. The model’s approach is based on the use of several dimensionless numbers, each of them having a clear physical significance, which play a key role in the analysis of the collector. The model is then used to conduct a thermodynamic optimization of VASC, which gives the optimal design parameters that maximize the exergy output of the heat extracted from the collector. The results agree with the findings made by other authors who have studied flat plate solar collectors.

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Hakim, Imansyah Ibnu, Nandy Putra, and Mohammad Usman. "Analysis of the use of thermoelectric generator and heat pipe for waste heat utilization." E3S Web of Conferences 67 (2018): 02057. http://dx.doi.org/10.1051/e3sconf/20186702057.

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Waste heat recovery is one way to reduce the use of fossil fuels, one of them is by using thermoelectric generator to convert waste heat into Thermoelectric Generator (TEGs) is a module that can convert heat into electrical power directly, using Seebeck effect and Peltier effect as its working principle, so it can increase efficiency of energy consumption by utilizing waste heat from an instrument that generate waste heat. The focus of this research is to find the output voltage of TEG by utilizing the temperature difference on the cold side and the heat side of the TEGs. The heat side of the module will be given heat from the heater as a simulation of the heat from hot water, and on the cold side heat pipes will be used to remove the heat on the cold side of TEGs. The result, output voltage that generated by using 4 module TEGs that arranged to Thermal Series - Series Circuit and using 2 heat pipes is 2.1-volt, and then it is possible to use for phone charger.

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Muniz, Pablo Rodrigues, Priscila Ribeiro Amorim de Almeida, and Raquel Perim Pereira. "EFFICIENT AND ERGONOMIC LOAD FOR DIDACTIC ELECTRICAL PANELS." Revista Ifes Ciência 4, no. 1 (June 15, 2018): 1–8. http://dx.doi.org/10.36524/ric.v4i1.321.

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Infrared thermography allows to detect defects even incipient, reducing maintenance costs and shutdown time. To accordingly perform the infrared inspection, the operator must be capacitated and well trained. There is difficulty nowadays in teaching thermographic inspection due to the lack of didactic equipment for this purpose. For that reason, a prototype set of switchgear was developed to be used as a didactic resource for teaching-learning infrared thermography applied to the predictive maintenance of electric installation in classrooms. Typically, an association of resistors as a load is used to generate a current large enough to cause a perceptible increase in temperature at the points of failure. But this load is large and overheating, making the class uncomfortable due to heat, and electric power cost is high. The purpose of this paper is to develop a new prototype that allows the circulation of electric current large enough to cause temperature rising dissipating low power. The present prototype connects the R, S and T switchgear phases in series from the original panel and feeds it through a direct current source, keeping it without internal modifications. This source can be adjusted to fit the need of current of the system, which was decided to be 20 A. The prototype has much lower cost than traditional resistive loads, is lightweight and easy to be transported. In addition, by reducing the dissipated power, it does not generate thermal discomfort in the classroom environment and reduces the costs with electric power about 90%.

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HONG, THONG DUC, QUAN PHAN THIEN NGHIEM, and TINH VAN MAI. "The experimental study on the performances of the thermoelectric generator unit affected by heat rate of exhaust system." Science & Technology Development Journal - Engineering and Technology 3, SI2 (January 22, 2021): SI24—SI36. http://dx.doi.org/10.32508/stdjet.v3isi2.558.

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This study examines the effect of heat rate transferring from the exhaust system of motorcycle to the environment on the performance of the Thermoelectric Generator Unit (TGU). This heat rate is changed by attaching thermal insulation material on the outside of the exhaust system and changing the heat absorbing area of the TGU. The TGU consists of 8 thermoelectric generator modules and collects heat energy from the exhaust to produce electricity. It is attached on the custom muffler of the Suzuki Sapphire 125 and tested in the speed range from 20km/h to 50km/h. The results show that this heat rate affects both the temperature and output power generated by the TGU. The reduction of this heat rate reduces the cool side temperature by limiting the warming effect of cooling air and raise the hot side temperature of the TGU by decreasing heat loss. These two effects lead to the increase of the temperature difference between both sides of the TGU and therefore the output power increases. The difference in output power between test cases can reach up to 54%. Moreover, the heat loss at exhaust tube affects both temperature and output power of TGU from low to mid vehicle speed. However, at high speed, this heat loss at the exhaust tube does not considerably affect the output power of the TGU. To summarize, by reducing the heat rate between exhaust system and environment, the TGU can reach its stable working condition faster and produces more output power. Nonetheless, reducing this heat rate too much may lead to the excess of the hot side temperature of TGU, therefore damaging the thermoelectric generator modules and reducing the conversion efficiency of the TGU.

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Zhong, Xiao Xing, Yun Chen, Guo Lan Dou, and De Ming Wang. "Effect of Experimental Conditions on Parameters Derived from Micro Calorimeter Measurements of Coal Low-Temperature Oxidation." Applied Mechanics and Materials 316-317 (April 2013): 850–53. http://dx.doi.org/10.4028/www.scientific.net/amm.316-317.850.

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C80 micro calorimeter was applied to investigate the initial heat release temperature and heat output at low-temperature oxidation process of Kabuliang anthracite coal under the experimental conditions of different coal sample mass, different temperature rising rates and different gas flow, and analyzed the effect of experimental conditions on test results. The results indicate that the coal sample mass and temperature rising rate affect measurement results, while there is no effect of gas flow. Under the same experimental condition, a higher temperature rising rate leads to a higher initial heat release temperature and less output of heat; The initial heat release temperature shows the trend of increase after decrease with the increase of coal sample mass. So, when micro calorimeter is used to investigate the coal low-temperature oxidation process, the experiments under the conditions of appropriate coal sample mass and the lower temperature rising rate can obtain more accurate test parameters.

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Weir, Graham J. "Heat output from spreading and rifting models of the Taupo Volcanic Zone, New Zealand." Journal of Applied Mathematics and Decision Sciences 5, no. 2 (January 1, 2001): 105–18. http://dx.doi.org/10.1155/s1173912601000098.

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A conceptual model of the Taupo Volcanic Zone (TVZ) is developed, to a depth of 25 km, formed from three constant density layers. The upper layer is formed from eruption products. A constant rate of eruption is assumed, which eventually implies a constant rate of extension, and a constant rate of volumetric creation in the middle and bottom layers. Tectonic extension creates volume which can accomodate magmatic intrusions. Spreading models assume this volume is distributed throughout the whole region, perhaps in vertical dykes, whereas rifting models assume the upper crust is thinned and the volume created lies under this upper crust. Bounds on the heat flow from such magmatic intrusions are calculated. Heat flow calculations are performed and some examples are provided which match the present total heat output from the TVZ of about 4200 MW, but these either have extension rates greater than the low values of about 8 ± 4 mm/a being reported from GPS measurements, or else consider extension rates in the TVZ to have varied over time.

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Weir, Graham. "Heat Output from Spreading and Rifting Models of the Taupo Volcanic Zone, New Zealand." Journal of Applied Mathematics and Decision Sciences 5, no. 2 (June 1, 2001): 105–18. http://dx.doi.org/10.1207/s15327612jamd0502_5.

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Roncarati, Davide, and Vincenzo Scarlato. "Regulation of heat-shock genes in bacteria: from signal sensing to gene expression output." FEMS Microbiology Reviews 41, no. 4 (April 11, 2017): 549–74. http://dx.doi.org/10.1093/femsre/fux015.

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Curtin, N. A., and R. C. Woledge. "EFFICIENCY OF ENERGY CONVERSION DURING SINUSOIDAL MOVEMENT OF WHITE MUSCLE FIBRES FROM THE DOGFISH SCYLIORHINUS CANICULA." Journal of Experimental Biology 183, no. 1 (October 1, 1993): 137–47. http://dx.doi.org/10.1242/jeb.183.1.137.

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Net work output and heat production of white myotomal muscle fibres from the dogfish were measured during complete cycles of sinusoidal movement at 12°C. The peak-to-peak movement was about 9 % of the muscle fibre length; three stimuli at 32 ms intervals were given in each mechanical cycle. The frequency of movement and the timing of the stimulation were varied for each preparation to find the optimal conditions for power output and those optimal for efficiency (the ratio of net work output to total energy output as heat+work). To achieve either maximum power or maximum efficiency, the tetanus must start while the muscle fibres are being stretched, before the beginning of the shortening part of the mechanical cycle. The highest power output, averaged over one cycle, was 0.23+/−0.014 W g-1 dry mass (+/−s.e.m., N=9, 46.9+/−2.8 mW g-1 wet mass) and was produced during movement at 3.5 Hz. The highest efficiency, 0.41+/−0.02 (+/−s.e.m., N=13), occurred during movements at 2.0-2.5 Hz. This value is higher than the efficiency previously measured during isovelocity shortening of these fibres. The implications of the high efficiency for crossbridge models of muscle contraction are discussed.

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Várfalvi, János, Jenő Kontra, Ján Takács, and Michal Krajčík. "Estimation and Measurement of Heat from Municipal Landfills." Applied Mechanics and Materials 832 (April 2016): 103–8. http://dx.doi.org/10.4028/www.scientific.net/amm.832.103.

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At present, deposition of garbage in landfills is one of the most popular methods to dispose of solid waste produced in municipal areas. In a landfill, large amounts of organic garbage is deposited, where certain types of bacteria flourish and decompose the garbage, whereby heat is produced as by-product. During the decades of operation, considerable quantities of heat are generated in these microbiologically active zones. In such zones, the temperature is typically about 40-60 °C. Knowing this quantities could obviously help planning an energy management system. In this respect, the objective is to extract as much heat from the landfill as possible, and utilize it for applications such as space heating, domestic hot water production, greenhouses, etc. The present paper aims to outline the methods of estimation of the amount of heat that is produced in a landfill during the decades of its operation. The methodology of measurement of thermal conditions and of the heat output capacity is presented, with an example of data, collected so far.

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Septiadi, Wayan Nata, Made Ricki Murti, Arliyandi, I. G. A. Pristha Arvikadewi, and I. Putu Yuda Pramana Putra. "Output voltage characteristic in system lighting road based on heat pipe and thermoelectric." E3S Web of Conferences 67 (2018): 02058. http://dx.doi.org/10.1051/e3sconf/20186702058.

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A novel design of a thermal management pavement system is introduced in this paper. The basic concept behind this design is a utilize of waste heat from asphalt pavement have as a base a heat pipe and thermoelectric for energy of street lighting. In this system, output voltage is influenced by difference in temperature between hot side and cold side of thermoelectric. The intensity of solar radiation at hourly is variant, so the resulting of output voltage fluctuated. The research method by field testing direct exposed solar radiation on the variation time at 09.00; 10.00; 11.00; 12.00; 13.00; 14.00; 15.00; 16.00 Indonesia Central Standard Time. The data of this research are surface temperature of asphalt pavement, difference in temperature between hot side and cold side of thermoelectric, and output voltage of system. The analysis process by quantitative experimental. In this research, the output voltage increased from 09.00 until 13.00, and after that time the output voltage decreased.

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Lombard, C. "Four-Port Representations of Heat Exchangers." International Journal of Mechanical Engineering Education 26, no. 1 (January 1998): 1–10. http://dx.doi.org/10.1177/030641909802600102.

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Two-port models represent a subsystem as a black box with an input and an output port. They are very convenient mathematical representations of subsystems, allowing easy connection between subsystem models to form a larger model. From an educational point of view, two-ports emphasize the idea of a subsystem as part of a larger structure. In this paper the concept is applied to two-stream heat exchangers, which are represented by a four-port model: two input ports and two output ports. It provides a new method of heat exchanger analysis which is complementary to the usual LMTD and effectiveness methods. It is easy to comprehend and ideal for computer programming. Large networks of heat exchangers are easily solved. In addition, it allows approximate models for heat exchangers with nonconstant properties as a cascade of constant property elements.

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Zhang, Yi, and Huan Yang. "Temperature Field and Refrigeration Output of Thermoelectric Arm." Advanced Materials Research 374-377 (October 2011): 508–11. http://dx.doi.org/10.4028/www.scientific.net/amr.374-377.508.

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Temperature field in thermoelectric arm and refrigeration output equation of a thermoelectric cooler was investigated by theoretical and experimental methods. Temperature differences between hot side and cold side were measured. Experimental data were used to prove the peak of the temperature parabola is located at hot side. The terms in refrigeration output equation can’t be explained as heat conducted from hot side to cold side and half of Joule heat respectively.

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Bala Bhaskara Rao, J., V. Ramachandra Raju, and BBVL Deepak. "A smart prediction tool for estimating heat transfer and overall pressure drop from shell-and-tube heat exchanger." Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering 231, no. 5 (June 24, 2016): 1053–62. http://dx.doi.org/10.1177/0954408916656388.

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Almost all thermal/chemical industries are equipped with heat exchangers in order to enhance the thermal efficiency. The performance of a shell and tube heat exchanger depends significantly on the design parameters like the tube cross-sectional area, tube orientation, baffle cut, etc. However, there are no specific relationships among these parameters to obtain an optimal design, such that the heat transfer rate is maximized and the pressure drop is minimized. Therefore, experimental and numerical simulations are carried out for a heat exchanger at various process parameters. Heat exchanger considered in this investigation is a single shell-multiple pass type device. For the performed experimental datasets, a generalized regression neural network is applied to generate a relation among the input and output process parameters.

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Murray, John, and Douglas Heggie. "From urban to national heat island: The effect of anthropogenic heat output on climate change in high population industrial countries." Earth's Future 4, no. 6 (June 2016): 298–304. http://dx.doi.org/10.1002/2016ef000352.

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Qi, Congzheng, Zemin Ding, Lingen Chen, Yanlin Ge, and Huijun Feng. "Modeling and Performance Optimization of an Irreversible Two-Stage Combined Thermal Brownian Heat Engine." Entropy 23, no. 4 (March 31, 2021): 419. http://dx.doi.org/10.3390/e23040419.

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Based on finite time thermodynamics, an irreversible combined thermal Brownian heat engine model is established in this paper. The model consists of two thermal Brownian heat engines which are operating in tandem with thermal contact with three heat reservoirs. The rates of heat transfer are finite between the heat engine and the reservoir. Considering the heat leakage and the losses caused by kinetic energy change of particles, the formulas of steady current, power output and efficiency are derived. The power output and efficiency of combined heat engine are smaller than that of single heat engine operating between reservoirs with same temperatures. When the potential filed is free from external load, the effects of asymmetry of the potential, barrier height and heat leakage on the performance of the combined heat engine are analyzed. When the potential field is free from external load, the effects of basic design parameters on the performance of the combined heat engine are analyzed. The optimal power and efficiency are obtained by optimizing the barrier heights of two heat engines. The optimal working regions are obtained. There is optimal temperature ratio which maximize the overall power output or efficiency. When the potential filed is subjected to external load, effect of external load is analyzed. The steady current decreases versus external load; the power output and efficiency are monotonically increasing versus external load.

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Ibrahim, O. M., S. A. Klein, and J. W. Mitchell. "Optimum Heat Power Cycles for Specified Boundary Conditions." Journal of Engineering for Gas Turbines and Power 113, no. 4 (October 1, 1991): 514–21. http://dx.doi.org/10.1115/1.2906271.

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Optimization of the power output of Carnot and closed Brayton cycles is considered for both finite and infinite thermal capacitance rates of the external fluid streams. The method of Lagrange multipliers is used to solve for working fluid temperatures that yield maximum power. Analytical expressions for the maximum power and the cycle efficiency at maximum power are obtained. A comparison of the maximum power from the two cycles for the same boundary conditions, i.e., the same heat source/sink inlet temperatures, thermal capacitance rates, and heat exchanger conductances, shows that the Brayton cycle can produce more power than the Carnot cycle. This comparison illustrates that cycles exist that can produce more power than the Carnot cycle. The optimum heat power cycle, which will provide the upper limit of power obtained from any thermodynamic cycle for specified boundary conditions and heat exchanger conductances is considered. The optimum heat power cycle is identified by optimizing the sum of the power output from a sequence of Carnot cycles. The shape of the optimum heat power cycle, the power output, and corresponding efficiency are presented. The efficiency at maximum power of all cycles investigated in this study is found to be equal to (or well approximated by) η=1−TL,in/φTH,in where φ is a factor relating the entropy changes during heat rejection and heat addition.

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38

McCollum, Artie, Jessica Geubtner, and Ione Hunt von Herbing. "Metabolic cost of feeding in Atlantic Cod (Gadus morhua) larvae using microcalorimetry." ICES Journal of Marine Science 63, no. 2 (January 1, 2006): 335–39. http://dx.doi.org/10.1016/j.icesjms.2005.10.007.

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Abstract A microcalorimeter that measures total heat output (μW) was used to determine total metabolic rate (aerobic and anaerobic) and the cost of feeding (specific dynamic action, SDA) in larval Atlantic cod (Gadus morhua) from hatching to 4 weeks post-hatch at 10°C. Total heat output increased throughout development from 2.14 μW at first-feeding to 23.72 μW at 4 weeks post-hatch. SDA was determined by comparing the total heat output among unfed larvae and fed larvae simultaneously. Total heat output increased in the first 2 h after feeding with rotifers (Brachionus sp.) and Artemia, remained high for up to 10 h, was significantly higher in fed larvae than in unfed larvae, and ranged from 16.56 μW at first-feeding to 47.84 μW at 4 weeks post-hatch. The differences in total heat output between unfed and fed larvae were 14.42 μW and 24.12 μW, representing an increase in metabolic cost of feeding by a factor of 1.67 over the first 4 weeks of larval life. That the metabolic cost of feeding increased with development and remained elevated suggests that cod larvae allocate a large part of their energy budget to growth in order to meet the demands of their fast growth rates.

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Orłowska, Magdalena. "Numerical analysis of a heat exchanger with differentiated temperatures surface at varying distances from the wall." E3S Web of Conferences 30 (2018): 03006. http://dx.doi.org/10.1051/e3sconf/20183003006.

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This article is one of a series of articles by the author. For many years she conducts research on convective heat exchange. The work is mainly concerned on knowing the effect of positioning the heater on the heat output of the device. It turns out that the correct location is very important.

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Kiselev, O. V., and Yu Sh Matros. "Heat output from the hot region in a thermal front propagating in a catalyst layer." Combustion, Explosion, and Shock Waves 23, no. 5 (1988): 655–62. http://dx.doi.org/10.1007/bf00756545.

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Brady, Laurence, Mawada Abdellatif, Jeff Cullen, James Maddocks, and Ahmed Al-Shamma’a. "An investigation into the effect of decorative covers on the heat output from LPHW radiators." Energy and Buildings 133 (December 2016): 414–22. http://dx.doi.org/10.1016/j.enbuild.2016.09.065.

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Ganio, Matthew S., Morten Overgaard, Thomas Seifert, Niels H. Secher, Pär I. Johansson, Martin A. S. Meyer, and Craig G. Crandall. "Effect of heat stress on cardiac output and systemic vascular conductance during simulated hemorrhage to presyncope in young men." American Journal of Physiology-Heart and Circulatory Physiology 302, no. 8 (April 15, 2012): H1756—H1761. http://dx.doi.org/10.1152/ajpheart.00941.2011.

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During moderate actual or simulated hemorrhage, as cardiac output decreases, reductions in systemic vascular conductance (SVC) maintain mean arterial pressure (MAP). Heat stress, however, compromises the control of MAP during simulated hemorrhage, and it remains unknown whether this response is due to a persistently high SVC and/or a low cardiac output. This study tested the hypothesis that an inadequate decrease in SVC is the primary contributing mechanism by which heat stress compromises blood pressure control during simulated hemorrhage. Simulated hemorrhage was imposed via lower body negative pressure (LBNP) to presyncope in 11 passively heat-stressed subjects (increase core temperature: 1.2 ± 0.2°C; means ± SD). Cardiac output was measured via thermodilution, and SVC was calculated while subjects were normothermic, heat stressed, and throughout subsequent LBNP. MAP was not changed by heat stress but was reduced to 45 ± 12 mmHg at the termination of LBNP. Heat stress increased cardiac output from 7.1 ± 1.1 to 11.7 ± 2.2 l/min ( P < 0.001) and increased SVC from 0.094 ± 0.018 to 0.163 ± 0.032 l·min−1·mmHg−1 ( P < 0.001). Although cardiac output at the onset of syncopal symptoms was 37 ± 16% lower relative to pre-LBNP, presyncope cardiac output (7.3 ± 2.0 l/min) was not different than normothermic values ( P = 0.46). SVC did not change throughout LBNP ( P > 0.05) and at presyncope was 0.168 ± 0.044 l·min−1·mmHg−1. These data indicate that in humans a cardiac output adequate to maintain MAP while normothermic is no longer adequate during a heat-stressed-simulated hemorrhage. The absence of a decrease in SVC at a time of profound reductions in MAP suggests that inadequate control of vascular conductance is a primary mechanism compromising blood pressure control during these conditions.

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Hrabovský, Peter, Zuzana Kolková, Jozef Matušov, and Patrik Nemec. "Ways to heat hot water via the heat pipes." MATEC Web of Conferences 168 (2018): 09003. http://dx.doi.org/10.1051/matecconf/201816809003.

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The article deals various ways of heating hot water where heat is transferred by the basic phenomena of heat transfer theories, which take place on an innovative basis with the advantage of the absence of mechanical elements. The heat transfer in this case ensures a change in the phase-in phase of the working substance – the fluid – from which the thermal output and the efficiency of the device are derived. The devices described in this article work on the same principle of heat transfer. Each device is characterized by own construction and the principle of heat transfer. Heat pipes are classified according to the way of operation and the place of use. Subdivision of the heat pipe, in terms of its actual, use in the desired temperature range. At present, heating plants use cooling technologies (nuclear power, space stations, IT).

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Zhang, Zhe, Yafeng Wu, Wenbin Li, and Daochun Xu. "Performance of a Solar Thermoelectric Power-Harvesting Device Based on an All-Glass Solar Heat Transfer Pipe and Gravity-Assisted Heat Pipe with Recycling Air Cooling and Water Cooling Circuits." Energies 13, no. 4 (February 20, 2020): 947. http://dx.doi.org/10.3390/en13040947.

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For the purpose of collecting solar radiation for energy conversion and utilization and improving the output performance of thermoelectric power-generation components, a new solar thermoelectric conversion device based on an all-glass solar heat transfer pipe and gravity-assisted heat pipe with recycling air cooling and water cooling circuits is designed. The uniqueness of the device lies in the combination of gravity-assisted heat pipes with excellent thermal conductivity and a direct air-cooled mode, a fin-cooled mode, and two solar-driven water-cooling modes with different flow rates. Based on the structure, the device can realize four separate output modes and multiple composite output modes and has practical significance for meeting different load power requirements, such as wireless sensors and electronics. Under a state of regular illumination from 3.14 × 104 lx to 10.04 × 104 lx, with one thermoelectric power generator (TEG) in one mode, the peak output voltage and power values of the device in single-output mode range from 183.1 mV to 370.7 mV and 33.5 mW to 137.2 mW, respectively, proving the feasibility of the proposed device. The energy supply of the above structure is completely obtained from the natural environment, and this aspect provides a high reference value for the cross-research of natural environment energy utilization and thermoelectric energy-conversion technology.

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Obaidullah, Md, Svend Bram, and Jacques De Ruyck De Ruyck. "Investigation on Gaseous and Particle Mass Emissions from Automatically Fired Small Scale Heating System under Laboratory Conditions." International Journal of Renewable Energy Development 7, no. 2 (July 10, 2018): 111–21. http://dx.doi.org/10.14710/ijred.7.2.111-121.

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This study presents the experimental results on gaseous and particle mass emissions obtained from a bottom feed pellet stove of 2.5 kW output in part load heat and 5 kW output in nominal heat. The experiments were conducted in a stove manufacturing plant in the southern part of Belgium. Two combustion experiments (A and B) in part load heat output and four experiments (C, D, E and E) in nominal load were performed at three combustion phases: startup, combustion and burnout phase. The pellet stove was operated in different fan speeds varied from 900 rpm to 1250 rpm for the combustion experiments. Experiments A and B were operated with low speed fan, C and D with medium speed fan, E and F with high speed fan. The emissions results include CO2, CO, O2 and particle mass concentrations are presented in this study. A performance analysis in terms of combustion efficiency together with different losses of the pellet stove is also discussed. The experimental results show that CO emissions obtained from the main combustion phase of the part load heat output experiments varied from 1215 mg/Nm3 to 1450 mg/Nm3, while in the nominal load heat output varied from 50 mg/Nm3 to 145 mg/Nm3. Also, the results show that CO emissions in the burnout phase from all the experiments were significantly higher than that in the startup phase followed by the combustion phase. The finding shows that higher CO emissions in the startup and burnout phase have influence on the total CO emissions. Particle mass emissions obtained from the combustion experiments operated with high fan speed varied from 10-15 mg/Nm3 respectively and were much lower than the required limit value of standard EN14785 and other works. The combustion efficiency obtained from all the experiments for the low speed fan, medium speed fan and high speed fan was 92.8±1.2 %, 92.4±1.1 % and 92.7±1.2 % respectively and satisfied the required limit value of the standard.Article History: Received Sept 12th 2017; Received in revised form March 17th 2018; Accepted April 26th 2018; Available onlineHow to Cite This Article: Obaidullah, M., Bram, S. and De Ruyck, J. (2018) Investigation on Gaseous and Particle Mass Emissions from Automatically Fired Small Scale Heating System under Laboratory Conditions. Int. Journal of Renewable Energi Development, 7(2), 111-121.https://doi.org/10.14710/ijred.7.2.111-121

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Zhou, Canzong, Shuyi Chen, Wei Cui, and Zhengmao Yao. "System Design of Electricity Generation Using Waste Heat from LNG Automobile." E3S Web of Conferences 145 (2020): 02062. http://dx.doi.org/10.1051/e3sconf/202014502062.

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According to the research, thermoelectricity generation can recycle the heat contained in the cooling system of internal combustion engine. This paper is about taking advantage of the feature in the huge temperature difference at about 560 °C which is formed between high-temperature engine and LNG (Liquefied Natural Gas) in low temperature and the ability that LNG provides semiconductor with thermoelectric conversion material so as to produce the maximum output voltage in low temperature. We take advantage of lead telluride materials that adapt to the high temperature environment and bismuth telluride materials that adapt to the low temperature environment, both of which forms a circuit and are designed as a thermoelectric power generation device. Also, we confirm the possibility of applying the device to cars.

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47

BARTON, N. G. "AN EVAPORATION HEAT ENGINE AND CONDENSATION HEAT PUMP." ANZIAM Journal 49, no. 4 (April 2008): 503–24. http://dx.doi.org/10.1017/s1446181108000035.

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AbstractThis paper presents a thermodynamic model for a heat engine based on evaporative cooling of unsaturated air at reduced pressure. Also analysed is a related heat pump based on condensation of water vapour in moist air at reduced pressure. These devices operate as two-stroke reciprocating engines, which are their simplest possible embodiments. The mathematical models for the two devices are based on conservation of mass for both air and water vapour, ideal gas laws, constant specific heats, and, as appropriate, either constant entropy processes or cooling/heating by evaporation/condensation. Both models take the form of coupled algebraic systems in six variables, which require numerical solution for certain stages of the cycle. The specific work output of the heat engine increases as the inlet air becomes hotter and as the expansion ratio of the engine increases. The engine provides evaporative cooling of air from inlet to outlet. The heat pump has a good coefficient of performance, which decreases as the expansion ratio increases. The heat pump also has the effect of drying the air from inlet to outlet, producing distilled water as a by-product.

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48

Curtin, N. A., and R. C. Woledge. "EFFICIENCY OF ENERGY CONVERSION DURING SINUSOIDAL MOVEMENT OF RED MUSCLE FIBRES FROM THE DOGFISH SCYLIORHINUS CANICULA." Journal of Experimental Biology 185, no. 1 (December 1, 1993): 195–206. http://dx.doi.org/10.1242/jeb.185.1.195.

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Bundles of red myotomal muscle fibres isolated from dogfish were electrically stimulated at 12 sC. Peak twitch force was 54 % of that produced by a brief isometric tetanus. Relaxation was slower than in white fibres, but much faster than would be expected for the tonic fibres found in amphibian muscle. These two results indicate that the red fibres in dogfish are slow, but not tonic, in their behaviour. Net work output and heat production were measured during complete cycles of sinusoidal movement. The following variables were kept constant: peak-to-peak movement, about 7 % of the muscle fibre length; tetanus duration, 33 % of the mechanical cycle time; stimulus frequency, 40 Hz. The frequency of movement and the timing of the stimulation were varied for each preparation to find the conditions optimal for power output and those optimal for efficiency (the ratio of net work output to total energy output as heat+work). To achieve either maximum power or maximum efficiency, the tetanus must start while the muscle fibres are being stretched, before the beginning of the shortening part of the mechanical cycle. The highest power output was produced during movement at 1.02 Hz. The highest efficiency, 0.507+/−0.045 (+/−s.e.m., N=9), was at 0.61-0.95 Hz. The efficiency is higher than that previously measured during sinusoidal movement of white fibres; the difference, 0.095+/− 0.045 (+/−s.e.m. of the difference, d.f. 20), is statistically significant at the 5 % level.

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Angeline A, Anitha, Jayakumar J, and Lazarus Godson Asirvatham. "Performance Analysis of (Bi2Te3-PbTe) Hybrid Thermoelectric Generator." International Journal of Power Electronics and Drive Systems (IJPEDS) 8, no. 2 (June 1, 2017): 917. http://dx.doi.org/10.11591/ijpeds.v8.i2.pp917-925.

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A theoretical analysis on the performance of (Bi2Te3-PbTe) hybrid thermoelectric generator (TEG) is presented in this paper. The effect of different performance parameters such as output voltage, output current, output power, maximum power output, open circuit voltage, Seebeck co-efficient, electrical resistance, thermal conductance, figure of merit, efficiency, heat absorbed and heat removed based on maximum conversion and power efficiency have been analyzed by varying the hot side temperature up to 350oC and by varying the cold side temperature from 30oC to 150oC. The results showed that a maximum power output of 21.7 W has been obtained with the use of one hybrid thermoelectric module for a temperature difference of 320oC between the hot and cold side of the thermoelectric generator at matched load resistance. The figure of merit was found to be around 1.28 which makes its usage possible in the intermediate temperature (250oC to 350oC) applications such as heating of Biomass waste, heat from Biomass cook stoves or waste heat recovery etc. It is also observed that the hybrid thermoelectric generator offers superior performance over 250oC of the hot side temperature, compared to standard Bi2Te3 modules

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Ninikas, Konstantinos, Nicholas Hytiris, Rohinton Emmanuel, and Bjorn Aaen. "Recovery and Valorisation of Energy from Wastewater Using a Water Source Heat Pump at the Glasgow Subway: Potential for Similar Underground Environments." Resources 8, no. 4 (October 30, 2019): 169. http://dx.doi.org/10.3390/resources8040169.

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An installation of a Water Source Heat Hump (WSHP) at Glasgow’s Underground Station, has been using the subsurface wastewater ingress to heat the office at St. George’s Cross station. The performance of the Glasgow Subway’s new heating system was observed for a few months. The energy output readings are being presented. An average coefficient of performance (CoP) of 2.5 and a 60% energy input reduction for the heating system based on the old heating system’s energy demand indicates the actual system’s performance. The purpose of this research is to detect the likelihood of implementing the same setup in similar underground environments where the excess wastewater may support a viable and eco-friendly heating system. Fifteen cities across Europe have been identified and presented, with the adequate water quantities, where similar heating systems may be applied. The output of this study indicates not only the financial benefit but also the energy and carbon reduction of this trial. It highlights main subjects which were encountered in such a challenging subway system. Future steps to commercialize the excess heat energy output are explored together with opportunities to promote the same setup in similar cases.

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Journal articles on the topic 'Heat output from the switchgear'

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