共查询到19条相似文献,搜索用时 125 毫秒
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热网管道热损失现场测试方法探讨程宗颐扬子石油化工公司节能办公室一、引言实验室内园管稳态热流,热损失测试方法比较成熟,但热网管道现场热损失测试时,遇到的往往是非稳态情况,增加了测试的难度。笔者谨以多年从事保温节能与现场热损失测试的实践,以现场实测与室内... 相似文献
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输热管道热损现场测试四种方法对比研究 总被引:1,自引:0,他引:1
一、引言在许多工业领域广泛应用的蒸汽或物料等输热管道的热损值,不仅是综合反映输热管道热设计、保温材料、施工工艺等总体水平的关键参数,而且是评估待改造管道或新建管道保温节能状况的主要依据。管道热损值还对由蒸汽加热的化工反应装置的工艺温度,从而对反应物的得率产生重大影响。因此,对输热管道热损进行现场测试方法的工程研究,具有十分明显的工程价值,本文是作者在北京燕山石化总公司和上海石化总公司开展输热管道热损现场测试方法研究结果的一篇总结。二、现场测试热损方法的基本原理至今,在国内外已应用并经我们试验验证… 相似文献
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利用地层热物性原位测试技术测得的地层热物性参数的精度要高于土壤类别辨识法或瞬态测量的探针法,更适于地源热泵系统埋管换热器的长度的设计。结合大广高速公路双辽服务区的地层热物性参数的测试情况对地层热物性原位测试的过程及施工注意事项进行简介。 相似文献
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An in situ thermal response test for borehole heat exchangers of the ground-coupled heat pump system
Thermal response tests (TRTs) are crucial for the estimation of the ground thermal properties and thermal performance of the borehole heat exchanger (BHE) of the ground-coupled heat pump (GCHP) system. In this article, a TRT apparatus was designed and built to measure the temperature response of inlet and outlet sections of BHE in the test borehole, the apparatus can effectively operate under both constant heating flux modes and heat injection and extraction modes with a constant inlet temperature. A TRT for a project of GCHP located in the Jiangsu province of China was carried out by the experimental apparatus. Based on the experimental data, the heat transfer performances of BHE under heating and cooling modes were evaluated, and the ground thermal properties, which include the ground thermal conductivity, ground volumetric specific heat, borehole thermal resistance and effective soil thermal resistance, were determined by the line source model. The results indicate that the experimental device and analysis model proposed in this article can be effectively applied to estimate the ground thermal properties and thermal performance of BHE. During the process of thermal response of ground, the fluid temperatures vary acutely at the start-stage of 8 h, and then tend to be a steady state after 40 h. The test data during the start-stage should be discarded for improving the estimation accuracy of ground thermal properties. At the same time, the effective soil thermal resistance increases continuously with time and a steady-state value would be reached after the start-time, and this steady-state thermal resistance can be used to evaluate the required length of BHE. In addition, the heat transfer rate of the BHE under different operating conditions can be used for the further evaluation on long-term operation performance of GCHPs. 相似文献
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动力电池能量密度的提升对于其安全性的测试评价技术提出了更高的要求。本文针对目前动力电池安全性的测试标准体系和评价方法等进行了总结和分析。具体的,在电池单体层面,分析了本征安全性(热稳定性)的表征方法以及触发安全性的测试标准体系现状及发展趋势等,在电池系统层面,重点探讨了电池系统安全性测试的标准体系以及热扩散的测试评价方法,希望能够为建立更加科学的定量测试与评价方法提供借鉴和参考。 相似文献
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The system performance of a ground source heat pump (HP) system is determined by the HP characteristics itself and by the thermal interaction between the ground and its borehole heat exchanger (BHE). BHE performance is strongly influenced by the thermal properties of the ground formation, grouting material, and BHE type. Experimental investigations on different BHE types and grouting materials were carried out in Belgium. Its performances were investigated with in situ thermal response tests to determine the thermal conductivity (λ) and borehole resistance (Rb). The line‐source method was used to analyze the results, and the tests showed the viability of the method. The main goal was to determine the thermal borehole resistance of BHEs, including the effect of the grouting material. The ground thermal conductivity was measured as 2.21 W m?1 K?1, a high value for the low fraction of water‐saturated sand and the high clay content at the test field. The borehole resistance for a standard coaxial tube with cement–bentonite grouting varied from 0.344 to 0.162 K W?1 m for the double U‐tube with cement–bentonite mixture (52% reduction). Grouting material based on purely a cement–bentonite mixture results in a high thermal borehole resistance. Addition of sand to the mixture leads to a better performance. The use of thermally enhanced grouts did not improve the performance significantly in comparison with only a low‐cost grouting material as sand. Potential future applications are possible in our country using a mobile testing device, such as characteristics, standardization, quality control, and certification for drilling companies and ground source HP applications, and in situ research for larger systems. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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M. H. Sharqawy E. M. Mokheimer M. A. Habib H. M. Badr S. A. Said N. A. Al‐Shayea 《国际能源研究杂志》2009,33(6):582-592
This paper presents energy, exergy and uncertainty analyses for the thermal response test of a ground heat exchanger. In this study, a vertical U‐shaped ground heat exchanger with 80 m depth and 20 cm borehole diameter is installed for the first time at the university premises in Saudi Arabia. A mobile thermal response apparatus is constructed and used to measure the performance of the ground heat exchanger. The thermal response test was carried out four times at different thermal loads from September 2007 to April 2008. The energy and exergy transports of these thermal response tests were analyzed using the experimental results obtained in this period. The analysis provides a better understanding of the overall performance of vertical ground heat exchangers, verifies the thermal response test results and improves the experimental setup. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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A new method for determining the equivalent parameters of a generalized thermal model of induction motors (IM) based on the no-load testing of IM is presented. The representation of the full thermal network of IM is reduced to a system of only three simultaneous equations. By solving these equations three equivalent thermal parameters of the generalized thermal model are obtained. The calculation is based on accurate measurements of the temperature rise in stator windings and the power absorbed by the tested motor. The thermal tests are done in the no-load running of IM (one test is like an open-circuit test and the other two are like short-circuit tests). Hence these methods of testing may be carried out without expensive equipment and their power consumption does not exceed the losses, which occur under full load conditions. With the help of this thermal model the final temperature rise at the full load run according to rated losses, can be easily estimated. Three totally enclosed IM were tested by these methods and the difference in the predicted and measured temperature rise of the stator winding was within 2-3°C 相似文献