地热能地板辐射采暖系统研究
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摘要
单井循环式地源热泵是一种高效换热地源热泵系统,在国外应用的时间已经比较长了,但在中国的应用才刚刚起步,目前国内在单井循环水源热泵理论与试验研究方面的积累几乎空白。以热虹吸管替代塑料管的地板辐射供暖系统是一种高效、节能、环保的新型采暖系统,其研究和应用在国内外鲜有报道,有很多问题值得商榷研究。为此,本文对以单井循环地下水源热泵作热源的热管地板辐射供暖进行了系统而全面的基础研究,主要内容如下:
1.单井循环地下水源热泵一维非稳态传热模型的建立与特性分析
①根据地下传热过程的特点,建立了井水与周围土壤一维非稳态温度场数学传热模型,并采用有限差分法进行数值求解。②在热泵供回水温差恒为5℃情况下,计算发现,远边界的温度在传热过程中起到非常重要的作用,但远边界设置不是无限远,应在井水温度变化影响范围之内。初始温度对井壁处热流密度大小没有影响,只有井的尺寸和井水流速才影响其取值,而半径显然较深度对运行时间的影响大。③初始温度、井水流速、井直径和井深都对单井取热极限有影响。
2.热管地板辐射供暖实验研究
利用热管地板辐射供暖与地下水源热泵联合运行实验台,在不同工况下对热管地板的温度分布、散热量、室内空气温度、地下水源热泵机组的性能进行了测试,实验结果表明:①热管地板传热效率高,且具有良好的蓄热性能,蓄热时间是预热时间的三倍左右;②供暖房间室内空气竖向温度梯度小;③与热管地板辐射供暖联合运行时,单井循环地下水源热泵不但可以满足供暖系统的要求,而且机组的运行性能良好。
Standing column wells in groundwater source heat pump is one kind of geothermy source heat pump with high efficiency in exchanging heat, the application of which is just in a preliminary stage in China. This well system has been applied for a long time abroad, while at present in China, the study of its theories and tests is almost blank. Thermosyphon-embedded floor radiant heating is a novel heating system with high efficiency, low energy consumption, and beneficial to protect environment. There were few related reports on study and application of this new radiant heating system not only domestic but also foreign.Therefore, a serial systematic and comprehensive study on standing column wells in groundwater source heat pump and thermosyphon-embedded floor radiant heating were expanded in this dissertation. The main work and results are listed as follows.
1. The establishment of one-dimensional transient heat-transfer model for standing column wells in groundwater source heat pump and the analysis of its characteristics
i) Mathematical model was established to describe the one-dimensional transient heat-transfer process between the well water and the soil around. Limited discrete method was adopted for numerical calculation, ii) It was found that the temprature of far boundary played very critical roles in the heat-transfer process though the setting of its boundary should not be unlimited but within the influencing scope of the well-water temprature under the condition of 5℃temprature difference between the supplying and recycling water in heat pump. The initial temperature had no impact on heat flux,which was influenced by the size of the well and the water velocity in it. Compared with the depth of the well, the size of its radius obviously exposed more influence on the operation time, iii) the initial temperature, well water velocity, and its diameter and depth had influences on the heat-extracted high-point of the standing column wells.
2. Experimental investigation on thermosyphon-embedded floor radiant heating.
Experimental system for thermosyphon-embedded floor radiant heating operating with ground water heat pump was built in this dissertation. Temperature distribution and heat transfer rate of thermosyphon-embedded floor, indoor air temperature, and performance of ground water heat pump were tested at different working conditions. Experimental results indicated that: i) thermosyphon-embedded floor has high heat transfer efficiency and good thermal storage capacity, ii) temperature gradient at human altitude in thermosyphon-embedded floor heating room is fairly small, iii) standing column wells in groundwater source heat pump working with thermosyphon-embedded floor radiant heating can not only satisfy the demand of heating system, but also perform well.
1.单井循环地下水源热泵一维非稳态传热模型的建立与特性分析
①根据地下传热过程的特点,建立了井水与周围土壤一维非稳态温度场数学传热模型,并采用有限差分法进行数值求解。②在热泵供回水温差恒为5℃情况下,计算发现,远边界的温度在传热过程中起到非常重要的作用,但远边界设置不是无限远,应在井水温度变化影响范围之内。初始温度对井壁处热流密度大小没有影响,只有井的尺寸和井水流速才影响其取值,而半径显然较深度对运行时间的影响大。③初始温度、井水流速、井直径和井深都对单井取热极限有影响。
2.热管地板辐射供暖实验研究
利用热管地板辐射供暖与地下水源热泵联合运行实验台,在不同工况下对热管地板的温度分布、散热量、室内空气温度、地下水源热泵机组的性能进行了测试,实验结果表明:①热管地板传热效率高,且具有良好的蓄热性能,蓄热时间是预热时间的三倍左右;②供暖房间室内空气竖向温度梯度小;③与热管地板辐射供暖联合运行时,单井循环地下水源热泵不但可以满足供暖系统的要求,而且机组的运行性能良好。
Standing column wells in groundwater source heat pump is one kind of geothermy source heat pump with high efficiency in exchanging heat, the application of which is just in a preliminary stage in China. This well system has been applied for a long time abroad, while at present in China, the study of its theories and tests is almost blank. Thermosyphon-embedded floor radiant heating is a novel heating system with high efficiency, low energy consumption, and beneficial to protect environment. There were few related reports on study and application of this new radiant heating system not only domestic but also foreign.Therefore, a serial systematic and comprehensive study on standing column wells in groundwater source heat pump and thermosyphon-embedded floor radiant heating were expanded in this dissertation. The main work and results are listed as follows.
1. The establishment of one-dimensional transient heat-transfer model for standing column wells in groundwater source heat pump and the analysis of its characteristics
i) Mathematical model was established to describe the one-dimensional transient heat-transfer process between the well water and the soil around. Limited discrete method was adopted for numerical calculation, ii) It was found that the temprature of far boundary played very critical roles in the heat-transfer process though the setting of its boundary should not be unlimited but within the influencing scope of the well-water temprature under the condition of 5℃temprature difference between the supplying and recycling water in heat pump. The initial temperature had no impact on heat flux,which was influenced by the size of the well and the water velocity in it. Compared with the depth of the well, the size of its radius obviously exposed more influence on the operation time, iii) the initial temperature, well water velocity, and its diameter and depth had influences on the heat-extracted high-point of the standing column wells.
2. Experimental investigation on thermosyphon-embedded floor radiant heating.
Experimental system for thermosyphon-embedded floor radiant heating operating with ground water heat pump was built in this dissertation. Temperature distribution and heat transfer rate of thermosyphon-embedded floor, indoor air temperature, and performance of ground water heat pump were tested at different working conditions. Experimental results indicated that: i) thermosyphon-embedded floor has high heat transfer efficiency and good thermal storage capacity, ii) temperature gradient at human altitude in thermosyphon-embedded floor heating room is fairly small, iii) standing column wells in groundwater source heat pump working with thermosyphon-embedded floor radiant heating can not only satisfy the demand of heating system, but also perform well.
引文
[1] 朗四维,龙惟定,林海燕,等.公共建筑节能设计标准宣贯辅导教材.北京:中国建筑工业出版社,2005,11
[2] 中华人民共和国建设部.贯彻落实科学发展观大力发展节能与绿色建筑.http://www.cin.gov.cn/green/yj/,2005-02-24
[3] 中华人民共和国建设部.建筑节能是关乎可持续发展的战略性举措. http://www.cin.gov.cn/green/yj/,2005-06-24
[4] 新华网.今年区域性、季节性电力缺口依然存在. http://news.xinhuanet.com/fortune//2006-03/18/content_4315339.htm, 2006-03-14
[5] Cube H L, Steimle F 著,王子介译.热泵的理论与实践.北京:中国建筑工业出版社,1986,36-39
[6] 庄骏, 张红.热管技术及其工程应用[M].北京: 化学工业出版社, 2000
[7] 马最良,姚杨,杨自强.水环热泵空调系统设计.北京:化学工业出版社,2005,1-2
[8] Zheng Deng.Modeling of Standing Column Wells in Ground Source Heat Pump Systems[D].Doctors thesis. Oklahoma(USA): Oklahoma State University,School of Mechanical and Aerospace Engineering,2004
[9] Bose, J.E., C. W. Ledbetter, and J. R. Partin. Experimental results of a low-cost solar-assisted heat pump system using earth coil and geo-thermal well storage. The 4th Annual Heat Pump Technology Conference, 1979, Stillwater, OK
[10] Orio, C.D. Geothermal heat pumps and standing column wells[J]. Geothermal Resources Council Transactions, 1994, 18: 376-379
[11] Oliver, J., and H. Braud. Thermal exchange to earth with concentric well pipes[J].Transactions of ASAE, 1981, 24(4): 906-910
[12] 倪龙, 封家平, 马最良.地下水源热泵的研究现状与进展[J].建筑热能通风空调, 2004, 23(2): 26-31
[13] HYY. Central Liquid State Cooling & Heating Source Environmental System Catalogue. Beijing ever source science & technology development Co. LTD. Beijing, China, 2000
[14] Tan, C. and E. Kush. Semi-closed loop standing column well groundwatersource heat pump. GHPC website www.geoexchange.org, 1986, R&D Project Profile No.3
[15] Mikler, V. A Theoretical and Experimental Study of the “Energy Well” Performance[D]. Masters thesis. Pennsylvania State University, College Park, PA, 1993
[16] Yuill, G.K. and V. Mikler. Analysis of the effect of induced groundwater flow on heat transfer from a vertical open-hole concentric-tube thermal well[J]. ASHRAE Transactions, 1995, 101(1): 173-185
[17] Orio, C D. Vertical earth coupling Kelvin line theory. Technical Bulletin #43. Water &Energy System Crop, Atkinson, NH, 1988
[18] Orio, C D. Geothermal heat pumps and standing column wells[J]. Geothermal Resources Council Transactions, 1994, 18: 376-379
[19] Orio, C.D. 1995. Design, use & example of standing column wells. IGSPHA Technical Meeting
[20] 冉春雨.塑料管地板采暖研究[J]. 暖通空调, 1999 (2)
[21] 孙德兴.低温热水供暖技术推广中尚需研究解决的问题[J]. 暖通空调, 2001, 32(3): 99-102
[22] Gaygker R S. Heat Transfer Device[P]. US: 2350348, 1944-06-06
[23] Grover G M, Cotter T P, Erikson G F. Structure of very high thermal conductance[J].Jounual of Applied Physics, 1964, 35(6)
[24] (美)SW 纪.热管理论及应用[M]. 蒋章焰译. 北京: 科学出版社, 1981
[25] E Schmidt. Proc. Instn. Mech. Engrs., Conf. ASME, London, 1951: 361-363
[26] Shirashi M K Kiiuchi, Yamanishi T. Investigation of Heat Transfer Characteristics of a Two-phase Closed Thermosyphon[A]. Proc. 4th IHPC[C], 1981
[27] K Negishi, T Sawada. Heat-transfer performance of an inclined two-phase closed thermosyphon[J]. International Journal of Heat Mass Transfer, 1983, 26(8): 1207-1213
[28] 倪龙, 马最良.热负荷对同井回灌地下水源热泵的影响[J]. 暖通空调, 2005, 3(3): 12-14, 23
[29] 倪龙, 马最良.含水层参数对同井回灌地下水源热泵的影响[J]. 天津大学学报, 2006, 39(2): 229-234
[30] Bhatti, M S and R H Shah. Turbulent and transition flow convective heat transfer in ducts, Handbook of Single-Phase Convective Heat Transfer [R]. New York(USA): John Wiley & Sons, Inc, 1987
[31] Chen, N H. An explicit equation for friction factor on pipe[J].Industrial and Engineering Chemistry Fundamentals, 1979,18: 296-297
[32] 陶文铨.数值传热学(第二版)[M].西安:西安交通大学出版社,2001.5.
[33] 章熙民.传热学[M]. 北京: 中国建筑工业出版社,1985
[34] B I Kilkis, M Eltez, S S Sager. A Simplified Model for the Design of Radiant In-slab Heating Panels[J]. ASHRAE Transactions, 1995, 101(1): 210-216
[35] I B Kilkis, M Sapci. Computer-aided Design of Radiant Subfloor Heating Systems[J]. ASHRAE Transactions, 1995, 101(1):1214-1220
[36] 方修睦, 姜永成, 张建利.建筑环境测试技术[M]. 北京: 中国建筑工业出版社, 2002
[2] 中华人民共和国建设部.贯彻落实科学发展观大力发展节能与绿色建筑.http://www.cin.gov.cn/green/yj/,2005-02-24
[3] 中华人民共和国建设部.建筑节能是关乎可持续发展的战略性举措. http://www.cin.gov.cn/green/yj/,2005-06-24
[4] 新华网.今年区域性、季节性电力缺口依然存在. http://news.xinhuanet.com/fortune//2006-03/18/content_4315339.htm, 2006-03-14
[5] Cube H L, Steimle F 著,王子介译.热泵的理论与实践.北京:中国建筑工业出版社,1986,36-39
[6] 庄骏, 张红.热管技术及其工程应用[M].北京: 化学工业出版社, 2000
[7] 马最良,姚杨,杨自强.水环热泵空调系统设计.北京:化学工业出版社,2005,1-2
[8] Zheng Deng.Modeling of Standing Column Wells in Ground Source Heat Pump Systems[D].Doctors thesis. Oklahoma(USA): Oklahoma State University,School of Mechanical and Aerospace Engineering,2004
[9] Bose, J.E., C. W. Ledbetter, and J. R. Partin. Experimental results of a low-cost solar-assisted heat pump system using earth coil and geo-thermal well storage. The 4th Annual Heat Pump Technology Conference, 1979, Stillwater, OK
[10] Orio, C.D. Geothermal heat pumps and standing column wells[J]. Geothermal Resources Council Transactions, 1994, 18: 376-379
[11] Oliver, J., and H. Braud. Thermal exchange to earth with concentric well pipes[J].Transactions of ASAE, 1981, 24(4): 906-910
[12] 倪龙, 封家平, 马最良.地下水源热泵的研究现状与进展[J].建筑热能通风空调, 2004, 23(2): 26-31
[13] HYY. Central Liquid State Cooling & Heating Source Environmental System Catalogue. Beijing ever source science & technology development Co. LTD. Beijing, China, 2000
[14] Tan, C. and E. Kush. Semi-closed loop standing column well groundwatersource heat pump. GHPC website www.geoexchange.org, 1986, R&D Project Profile No.3
[15] Mikler, V. A Theoretical and Experimental Study of the “Energy Well” Performance[D]. Masters thesis. Pennsylvania State University, College Park, PA, 1993
[16] Yuill, G.K. and V. Mikler. Analysis of the effect of induced groundwater flow on heat transfer from a vertical open-hole concentric-tube thermal well[J]. ASHRAE Transactions, 1995, 101(1): 173-185
[17] Orio, C D. Vertical earth coupling Kelvin line theory. Technical Bulletin #43. Water &Energy System Crop, Atkinson, NH, 1988
[18] Orio, C D. Geothermal heat pumps and standing column wells[J]. Geothermal Resources Council Transactions, 1994, 18: 376-379
[19] Orio, C.D. 1995. Design, use & example of standing column wells. IGSPHA Technical Meeting
[20] 冉春雨.塑料管地板采暖研究[J]. 暖通空调, 1999 (2)
[21] 孙德兴.低温热水供暖技术推广中尚需研究解决的问题[J]. 暖通空调, 2001, 32(3): 99-102
[22] Gaygker R S. Heat Transfer Device[P]. US: 2350348, 1944-06-06
[23] Grover G M, Cotter T P, Erikson G F. Structure of very high thermal conductance[J].Jounual of Applied Physics, 1964, 35(6)
[24] (美)SW 纪.热管理论及应用[M]. 蒋章焰译. 北京: 科学出版社, 1981
[25] E Schmidt. Proc. Instn. Mech. Engrs., Conf. ASME, London, 1951: 361-363
[26] Shirashi M K Kiiuchi, Yamanishi T. Investigation of Heat Transfer Characteristics of a Two-phase Closed Thermosyphon[A]. Proc. 4th IHPC[C], 1981
[27] K Negishi, T Sawada. Heat-transfer performance of an inclined two-phase closed thermosyphon[J]. International Journal of Heat Mass Transfer, 1983, 26(8): 1207-1213
[28] 倪龙, 马最良.热负荷对同井回灌地下水源热泵的影响[J]. 暖通空调, 2005, 3(3): 12-14, 23
[29] 倪龙, 马最良.含水层参数对同井回灌地下水源热泵的影响[J]. 天津大学学报, 2006, 39(2): 229-234
[30] Bhatti, M S and R H Shah. Turbulent and transition flow convective heat transfer in ducts, Handbook of Single-Phase Convective Heat Transfer [R]. New York(USA): John Wiley & Sons, Inc, 1987
[31] Chen, N H. An explicit equation for friction factor on pipe[J].Industrial and Engineering Chemistry Fundamentals, 1979,18: 296-297
[32] 陶文铨.数值传热学(第二版)[M].西安:西安交通大学出版社,2001.5.
[33] 章熙民.传热学[M]. 北京: 中国建筑工业出版社,1985
[34] B I Kilkis, M Eltez, S S Sager. A Simplified Model for the Design of Radiant In-slab Heating Panels[J]. ASHRAE Transactions, 1995, 101(1): 210-216
[35] I B Kilkis, M Sapci. Computer-aided Design of Radiant Subfloor Heating Systems[J]. ASHRAE Transactions, 1995, 101(1):1214-1220
[36] 方修睦, 姜永成, 张建利.建筑环境测试技术[M]. 北京: 中国建筑工业出版社, 2002
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