西安建筑科技大学学报(自然科学版)

土壤源热泵能否被进一步推广应用,很大程度取决于其准确、可靠的测试与设计方法. 现行规范中采用恒热流热响应法测试土壤的导热系数等热物性参数,设计人员据此进行埋管量设计. 然而,受测试条件和理论模型限制,整个测试过程及后续数据处理方法存在诸多不确定因素,客观上造成通过测试较难提供准确的热物性参数,设计时也难以准确计算所需埋管量. 为解决这一问题,首先基于线热源模型和理论分析,提出了反映土壤侧换热规律的动态传热模型. 其次,进行恒温热响应测试,研究土壤源热泵不同运行模式下的换热特性. 实验验证结果表明,建立的模型对恒温热响应测试出口温度的估计,运行5 h后绝对误差小于0.5 ℃,相对误差小于2%. 提出的土壤源热泵测试与设计方法,可为土壤源热泵系统优化设计和高效运行提供理论指导.

One of the keys to further popularize the application of ground source heat pumps(GCHP)lies in their accurate and reliable testing and design methods. In the current specification, the constant-heat flow thermal response method is used to test the thermal conductivity and other thermal parameters of the soil, and the designer designs the size of the ground heat exchanger(GHE)accordingly. Due to the limitation of test conditions and theoretical models, there are many uncertain factors in the whole test process and subsequent data processing method, which objectively make it difficult to provide accurate thermal property parameters through the test, and which also make it difficult to accurately calculate the required size of GHE during design. To solve these problems, based on the linear heat source model and theoretical analysis, this paper firstly proposes a dynamic heat transfer model reflecting the soil side heat transfer law. Secondly, the constant-temperature thermal response test is carried out to study the heat transfer performance and related influencing factors under different operating modes of GCHP. The experimental verification results show that the absolute error of the model established in this paper is less than 0.5 ℃ and the relative error is less than 2% for the estimation of the outlet temperature of the constant temperature thermal response test after 5 h of operation. The new method for testing and design of GCHP proposed in this paper can provide an important theoretical direction for the optimal design and efficient operation of GCHP.

引言
1 恒温热响应测试传热模型
2 GHE传热性能实验研究
3 实验结果与分析
4 结论

图1 恒温热响应动态传热模型应用计算程序框图<br/>Fig.1 Flow chart of the constant-temperature TRT dynamic heat transfer model calculation and application

图1 恒温热响应动态传热模型应用计算程序框图
Fig.1 Flow chart of the constant-temperature TRT dynamic heat transfer model calculation and application

图2 实验装置示意图<br/>Fig.2 Schematic diagram of the test rig

图2 实验装置示意图
Fig.2 Schematic diagram of the test rig

图3 恒温热响应测试平台<br/>Fig.3 Test rig of the constant-temperature TRT

图3 恒温热响应测试平台
Fig.3 Test rig of the constant-temperature TRT

表1 测试使用的设备参数<br/>Tab.1 Parameters of the equipment used in this test

表1 测试使用的设备参数
Tab.1 Parameters of the equipment used in this test

表2 测量仪器及其精度

图4 GHE出口温度计算值与实测值的对比<br/>Fig.4 Comparison of outlet temperature of GHE for calculated value and test value

图4 GHE出口温度计算值与实测值的对比
Fig.4 Comparison of outlet temperature of GHE for calculated value and test value

图5 GHE出口温度计算值与实测值误差分析<br/>Fig.5 Error analysis for calculated and test outlet fluid temperature of GHE

图5 GHE出口温度计算值与实测值误差分析
Fig.5 Error analysis for calculated and test outlet fluid temperature of GHE

图6 连续运行下GHE的传热特性<br/>Fig.6 Heat transfer performance of GHE under different operation modes

图6 连续运行下GHE的传热特性
Fig.6 Heat transfer performance of GHE under different operation modes

图7 间歇运行下GHE的传热特性(间歇比1:1)<br/>Fig.7 Heat transfer performance of GHE under different operation modes(intermittent ratio1:1)

图7 间歇运行下GHE的传热特性(间歇比1:1)
Fig.7 Heat transfer performance of GHE under different operation modes(intermittent ratio1:1)

图8 不同运行模式传热性能的对比<br/>Fig.8 Comparisons of heat transfer performance under different operation modes

图8 不同运行模式传热性能的对比
Fig.8 Comparisons of heat transfer performance under different operation modes

图9 不同运行模式下单位井深换热量的稳态值和积分平均值<br/>Fig.9 Steady-state value and integral average of the heat transfer rate per unit depth of borehole under different operation modes

图9 不同运行模式下单位井深换热量的稳态值和积分平均值
Fig.9 Steady-state value and integral average of the heat transfer rate per unit depth of borehole under different operation modes

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备注

引言

1 恒温热响应测试传热模型

2 GHE传热性能实验研究

3 实验结果与分析

4 结论

期刊信息