The Experimental Research on Instantaneous Efficiency of PV/T Module Based on Micro Heat Pipe Array

2013 ◽  
Vol 732-733 ◽  
pp. 306-311
Author(s):  
Zhen Hua Quan ◽  
Lin Cheng Wang ◽  
Yao Hua Zhao ◽  
Yue Chao Deng ◽  
Gang Wang ◽  
...  
Keyword(s):  
Solar Cell ◽  
Heat Pipe ◽  
Thermal Efficiency ◽  
Power Efficiency ◽  
Waste Heat ◽  
Energy Utilization ◽  
Inlet Temperature ◽  
Total Efficiency ◽  
Micro Heat Pipe ◽  
Key Factor

A novel photovoltaic /thermal (PV/T) module is invented, which use micro heat pipe array (MHPA), a flat heat pipe, to cool the solar cell. The PV/T module can achieve the purpose of cogeneration by collecting and utilizing waste heat while cooling the solar cell and improving power efficiency. In order to test the performance of PV/T module based on MHPA, instantaneous thermal efficiency test was performed. The intercept of measured instantaneous thermal efficiency curve can reach 41.4%, the slope is 3.95. The temperature of PV module is the key factor of the influencing electric efficiency. The PV/T modules electric efficiency is kept between 10.5% and 12.3% during the test. Solar energy utilization total efficiency at 20°C inlet temperature can reach more than 50%, and comprehensive performance efficiency can reach above 70%.

Energy and exergy analysis of hydraulic free-piston engines

2018 ◽  
Vol 233 (12) ◽  
pp. 3074-3087 ◽  
Author(s):  
Lei Wang ◽  
Zhenfeng Zhao ◽  
Chuncun Yu ◽  
Fujun Zhang ◽  
Changlu Zhao
Keyword(s):  
Thermal Efficiency ◽  
Waste Heat ◽  
Energy Utilization ◽  
Injection Timing ◽  
Characteristic Parameters ◽  
Piston Engine ◽  
Free Piston ◽  
Free Piston Engine ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis

A hydraulic free-piston engine is an unconventional reciprocating piston internal combustion engine in which the piston assembly motion is determined by in-cylinder gas pressure and load force. Fuel combustion energy is directly converted into hydraulic energy. These affect the work process of cylinder and efficiency of energy conversion. In order to study the energy utilization efficiency and to explore the recovery potential of waste heat energy of hydraulic free-piston engine, in this paper, the energy distribution and waste heat energy characteristics of hydraulic free-piston engine have been studied by combining energy and exergy analysis. The thermal efficiency was analyzed by the first law of thermodynamics, and exergy balance was analyzed by the second law. The effect of the characteristic parameters on the thermal and exergy efficiency was studied through the simulation analysis comparing the energy utilization of hydraulic free-piston engine and conventional engines. The results show that control of the injection timing parameter is effective for optimizing efficiency because the cycle characteristic parameters can be controlled by changing the injection timing. The experimental results show that the thermal efficiency is 40.8% and the exergy efficiency is 46.3%. The simulation result show that the thermal efficiency of hydraulic free-piston engine is 38.0% and the conventional diesel engine is 33.0%.

The Experimental Study of New-Type Water-Cooling PV/T Collector

2011 ◽  
Vol 374-377 ◽  
pp. 242-247 ◽  
Author(s):  
Ning Jun Li ◽  
Zhen Hua Quan ◽  
Yao Hua Zhao ◽  
Na Na Guo
Keyword(s):  
Experimental Study ◽  
Waste Heat ◽  
Hot Water ◽  
Energy Utilization ◽  
Utilization Efficiency ◽  
Total Efficiency ◽  
Forced Circulation ◽  
Electrical Efficiency ◽  
Pv Modules ◽  
T System

A new photovoltaic/thermal (PV/T) system based on the micro plate heat pipe is established in this paper, and the experimental study is conducted for nature convection, forced circulation cooling and common PV module. the experiment carried out on May showed that the highest temperature were 50°C and 52°C respectively for nature convection and forced circulation cooling module, the daily average electrical efficiency were relatively increased by 13.1% and 6.1% than common PV modules, the total efficiency ηo reached 54.2% and 50.3%, and the primary-energy saving rate were 73.1% and 68%.the result indicates that in the new PV/T system the temperature of the PV modules is reduced, the electrical efficiency is keeping at a high level, and the waste heat can be made good use to get hot water, therefore the solar energy utilization efficiency was raised greatly.

scholarly journals Thermal Performance of a Low-Temperature Heat Exchanger Using a Micro Heat Pipe Array

Energies ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 675 ◽  
Author(s):  
Jingang Yang ◽  
Yaohua Zhao ◽  
Aoxue Chen ◽  
Zhenhua Quan
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Exchange ◽  
Low Temperature ◽  
Heat Pipe ◽  
Thermal Performance ◽  
Flue Gas ◽  
Thermal Efficiency ◽  
Heat Exchangers ◽  
Micro Heat Pipe

Domestic heat exchangers, even though widely used in industry, are not adequate for studies on low-temperature flue-gas use technologies. Despite spite their limitations, very few theoretical models have been investigated based on practical applications. Moreover, most of the existing studies on heat exchangers have focused particularly on one-dimensional and two-dimensional heat transfer models, while limited studies focus on three-dimensional ones. Therefore, this study aims at investigating the thermal performance of a low-temperature flue-gas heat recovery unit in the cold regions. Specifically, this study was conducted in the context of Changchun of Jilin Province, China, a city with the mean ambient temperature of −14 °C and mean diurnal temperature of −10 °C during winter. Experimental results showed that the thermal efficiency of the heat exchanger was higher than 60%. Through assessing the heat exchange coefficient and heat exchange efficiency of the heat exchanger, it is found that the thermal efficiency had been improved up to 0.77–0.83. Furthermore, the ICEPAK software and the standard k-ε RNG turbulence model were used to carry out simulations. The velocity and outlet temperature of fresh airflow and polluted airflow were simulated through setting different inlet temperatures of fresh air and polluted air inlet. Numerical results further indicated that the flow state was laminar flow. The micro heat pipe array side had small eddies and the heat transfer was significantly improved due to the flow of air along the surface of the micro heat pipe.

Thermo-Economic Analysis of a Recompression Supercritical CO2 Cycle Combined With a Transcritical CO2 Cycle

2015 ◽  
Author(s):  
Xurong Wang ◽  
Yi Wu ◽  
Jiangfeng Wang ◽  
Yiping Dai ◽  
Danmei Xie
Keyword(s):  
Thermal Efficiency ◽  
Waste Heat ◽  
Expansion Ratio ◽  
Capital Cost ◽  
Inlet Pressure ◽  
Inlet Temperature ◽  
Condensation Temperature ◽  
Turbine Expansion ◽  
Turbine Inlet ◽  
Net Power Output

The transcritical CO2 cycle (TCO2 cycle) exhibits good performance in low-grade waste heat recovery area. In this study, a TCO2 cycle was employed as a bottoming cycle to recover the waste heat in the topping recompression supercritical CO2 Brayton cycle (SCO2 cycle). A detailed system analysis was performed of a recompression SCO2 cycle combined with a TCO2 cycle to improve the efficiency of energy conversion. Thermodynamic analysis, calculation of heat exchangers’ area and economic analysis were considered. The SCO2 turbine expansion ratio, TCO2 turbine inlet pressure, high temperature recuperator (HTR) effectiveness and condensation temperature were studied to investigate their effect on the system performance. For the basic analysis, SCO2 turbine inlet temperature was conservatively selected to be 550 °C and the compressor outlet pressure set at 20 MPa. For these operating conditions the proposed combined SCO2-TCO2 cycle yielded about 46% thermal efficiency at a SCO2 turbine expansion ratio of 2.7 and TCO2 turbine inlet pressure of 10 MPa. Similarly, the capital cost per net power output of the combined cycle was found as 6.6 k$/kW, which was ∼ 6% more expensive than that of the recompression SCO2 cycle without the bottoming cycle under the same operating condition. An optimum TCO2 turbine inlet pressure and an optimum SCO2 turbine expansion ratio existed where the system thermal efficiency reached the maximum value. Furthermore, the system thermal efficiency was very sensitive to the changes in the condensation temperature and the HTR effectiveness. The HTR effectiveness also had a strong effect on the ratio of heat exchangers’ cost to the plant capital cost. Additionally, increasing SCO2 turbine inlet temperature would significantly improve the cycle overall thermal efficiency and decrease the plant capital cost per net power output.

scholarly journals Parametric Optimisation of an ORC in a Wood Chipboard Production Facility to Recover Waste Heat Produced from the Drying and Steam Production Process

Energies ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3656 ◽  
Author(s):  
Yıldız Koç
Keyword(s):  
Thermal Efficiency ◽  
Waste Heat ◽  
Saturated Steam ◽  
Maximum Temperature ◽  
Inlet Temperature ◽  
Drying Process ◽  
Turbine Inlet Temperature ◽  
Turbine Inlet ◽  
Cogeneration System ◽  
Steam Production

The wastes in wood industries (waste chips) are commonly used as fuel for burners to produce steam and to use the remaining heat in the drying process. However, in spite of that, there is a considerable amount of heat evaluated from the burn of waste chips still released to the atmosphere without use. Therefore, in the present study, a cogeneration cycle design by used of ORC was designed and parametrically optimised for six organic working fluids (acetone, ethanol, R11, RE245fa2, R365mfc and R601a). During the ORC optimisation, the ORC turbine inlet temperature was changed from the saturated steam temperature of the fluid to the maximum temperature of the fluid. The ORC turbine inlet pressure was increased from 7.5 bar to the critical pressure of the fluid. As a result of the study, the maximum net power, net thermal efficiency and exergy efficiency of the ORC were found as 453.91 kW, 30.01% and 67.56% at 340 °C and 62.5 bar from the ORC with ethanol. This means that almost 30% of the waste heat could be recovered by use of the ORC with ethanol. By using the designed cogeneration system, it was calculated that the thermal efficiency of the system can be increased up to 74.01%.

scholarly journals Exergy Analysis of Biomass-Fired Cogeneration Plant in a Pulp and Paper Mill

1993 ◽  
Author(s):  
Ann-Sofi E. Näsholm ◽  
Gunnar Svedberg ◽  
Mats O. J. Westermark
Keyword(s):  
Gas Turbine ◽  
Exergy Analysis ◽  
Waste Heat ◽  
Combined Cycle ◽  
Pulp And Paper ◽  
Energy Utilization ◽  
Saturated Steam ◽  
Total Efficiency ◽  
Steam Boiler ◽  
Cogeneration Plant

Second Law analysis or exergy analysis is a useful instrument to find ways to improve the efficiency of energy utilization. The method presents the magnitude and locations of true energy losses in an energy system. The pulp and paper industries have a big potential for increasing the energy efficiencies. An integration of a gas turbine with an existing steam turbine plant is one possible way to increase the energy efficiency and the power production. The cogeneration plant analysed in this paper is a hybrid combined plant in which two types of fuels are used. The exhaust gas from a combined cycle gas turbine via a waste heat recovery steam generator (HRSG) is used as preheated combustion air in a supplementary fired steam boiler. Saturated steam from the HRSG is assumed to be superheated in a boiler in which sludge, bark and other types of biomass are being used as fuels. To reduce the waste of energy, a flue gas driven fuel dryer is connected to evaporate some of the moisture in these biomass fuels. The study shows the effect of using a combined cycle instead of a simple steam cycle and the effect of using a fuel dryer. Among the configurations investigated, a plant with both a gas turbine and a fuel dryer yields the highest exergy efficiency and total efficiency. However, the net power efficiency is higher for a plant without a fuel dryer than for one with a fuel dryer.

Design Performance Simulation of a Supercritical CO2 Cycle Coupling With a Steam Cycle for Gas Turbine Waste Heat Recovery

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Ziwei Bai ◽  
Guoqiang Zhang ◽  
Yongping Yang ◽  
Ziyu Wang
Keyword(s):  
Flue Gas ◽  
Heat Recovery ◽  
Waste Heat ◽  
Water Cycle ◽  
Rankine Cycle ◽  
Energy Utilization ◽  
Inlet Temperature ◽  
Specific Work ◽  
Reheating Process ◽  
Turbine Exhaust

This study presents a train of thought and method for flue gas energy utilization management by connecting an optimized supercritical carbon dioxide (S-CO2) Brayton cycle with a selected steam/water Rankine cycle to recover the turbine exhaust gas heat with promising flue gas coupling capacity. Better performance over the currently used steam/water bottoming cycle is expected to be obtained by the combined bottoming cycle after the S-CO2 cycle is coupled with the high-temperature flue gas. The performances of several S-CO2 cycles are compared, and the selected steam/water cycle is maintained with constant flue gas inlet temperature to properly utilize the low-temperature flue gas. Aspen Plus is used for simulating the cycle performances and the flue gas heat duty. Results show that the recompression S-CO2 cycle with the reheating process is most recommended to be used in the combined bottoming cycle within the research scope. The suggested combined bottoming cycle may outperform most of the triple reheat steam/water cycles for the turbine exhaust temperature in the range of 602–640 °C. Subsequently, it is found that the intercooling process is not suggested if another heat recovery cycle is connected. Moreover, the specific work of the suggested S-CO2 cycles is calculated, and the bottoming cycle with the preheating cycle with the reheating process is found to be more compact than any other combined bottoming cycles.

scholarly journals A Structural Review of Thermoelectricity for Fuel Cell CCHP Applications

2020 ◽  
Vol 2020 ◽  
pp. 1-23 ◽  
Author(s):  
Nganyang Paul Bayendang ◽  
Mohamed Tariq Kahn ◽  
Vipin Balyan
Keyword(s):  
Fuel Cell ◽  
Output Power ◽  
Temperature Difference ◽  
Power Efficiency ◽  
Waste Heat ◽  
Thermal Environment ◽  
Tracking Error ◽  
Power Converter ◽  
Total Efficiency ◽  
Practical Applications

This article starts by introducing the ongoing South Africa electricity crisis followed by thermoelectricity, in which eighteen miscellaneous applicable case studies are structurally analysed in detail. The aim is to establish best practices for the R&D of an efficient thermoelectric (TE) and fuel cell (FC) CCHP system. The examined literature reviews covered studies that focused on the thermoelectricity principle, highlighting TE devices’ basic constructions, TEGs and TECs as well as investigations on the applications of thermoelectricity with FCs, whereby thermoelectricity was applied to recover waste heat from FCs to boost the power generation capability by ~7–10%. Furthermore, nonstationary TEGs whose generated power can be increased by pulsing the DC-DC power converter showed that an output power efficiency of 8.4% is achievable and that thicker TEGs with good area coverage can efficiently harvest waste heat energy in dynamic applications. TEG and TEC exhibit duality and the higher the TEG temperature difference, the more the generated power—which can be stabilised using the MPPT technique with a 1.1% tracking error. A comparison study of TEG and solar energy demonstrated that TEG generates more power compared to solar cells of the same size, though more expensively. TEG output power and efficiency in a thermal environment can be maximised simultaneously if its heat flux is stable but not the case if its temperature difference is stable. The review concluded with a TEC LT-PEM-FC hybrid CCHP system capable of generating 2.79 kW of electricity, 3.04 kW of heat, and 26.8 W of cooling with a total efficiency of ~77% and fuel saving of 43.25%. The presented research is the contribution brought forward, as it heuristically highlights miscellaneous thermoelectricity studies/parameters of interests in a single manuscript, which further established that practical applications of thermoelectricity are possible and can be innovatively applied together with FC for efficient CCHP applications.

scholarly journals Study on application technology of pulsating heat pipe

2021 ◽  
Vol 248 ◽  
pp. 01051
Author(s):  
Jianhong Liu ◽  
Fumin Shang ◽  
Kangzhe Yang ◽  
Chaoyue Liu ◽  
Yong Wu
Keyword(s):  
Heat Pipe ◽  
Large Scale ◽  
Small Volume ◽  
Waste Heat ◽  
Low Cost ◽  
Energy Utilization ◽  
Low Grade ◽  
Pulsating Heat Pipe ◽  
Application Technology ◽  
Good Heat

Pulsating heat pipe(PHP) has many advantages, such as small volume, simple structure, low cost, good heat transfer performance, it have great potential in the application of refrigeration, aerospace, waste heat recovery and low - grade energy utilization. Based on the analysis of a large number of research results at home and abroad, the application status of pulsating heat pipe technology is summarized in this paper, which can provide scientific guidance for the design, operation and large-scale application of pulsating heat pipe.

NUMERICAL AND EXPERIMENTAL INVESTIGATION ON A NEW TYPE ELECTRICAL HEAT STORAGE BASED ON FLAT MICRO HEAT PIPE

2018 ◽  
Author(s):  
Zeyu Wang ◽  
Yanhua Diao ◽  
Yaohua Zhao ◽  
Chuanqi Chen ◽  
Lin Liang ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Heat Pipe ◽  
Heat Storage ◽  
Micro Heat Pipe ◽  
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