土壤源热泵取热的实验研究

通过广泛分析国内外对土壤源热泵实验研究的现状,建立了可以模拟多个地区、多种运行工况的土壤源热泵沙箱实验台,并进行了绝热边界工况短期内取热的实验研究。     

U型埋管换热器及其周围土壤非稳态传热的数值分析

针对地源热泵U型换热器埋管、周围回填材料及土壤传热过程,建立了将U型管壁的边界换热取为第三类对流换热条件的二维非稳态传热模型,并对其温度分布进行了数值模拟分析．分析结果表明：U型埋管换热器管壁内对流换热热阻和管壁导热热阻对U型埋管换热器及其周围土壤非稳态传热过程的影响较小,但相互热干扰造成进、出水管壁自身各角度的温度存在明显差异．各处土壤温度达到准稳定阶段所需要的时间随其与U型埋管的距离增加而增加．     

Developing multiple regression models from the manufacturer's ground-source heat pump catalogue data

The performance of ground-source heat pumps (GSHP), often expressed as Power drawn and/or the COP, depends on several operating parameters. Manufacturers usually publish such data in tables for certain discrete values of the operating fluid temperatures and flow rates conditions. In actual applications, such as in dynamic simulations of heat pump system integrated to buildings, there is a need to determine equipment performance under operating conditions other than those listed. This paper describes a simplified methodology for predicting the performance of GSHPs using multiple regression (MR) models as applicable to manufacturer data. We find that fitting second-order MR models with eight statistically significant x-variables from 36 observations appropriately selected in the manufacturer catalogue can predict the system global behavior with good accuracy. For the three studied GSHPs, the external prediction error of the MR models identified following the methodology are 0.2%, 0.9% and 1% for heating capacity (HC) predictions and 2.6%, 4.9% and 3.2% for COP predictions. No correlation is found between residuals and the response, thus validating the models. The operational approach appears to be a reliable tool to be integrated in dynamic simulation codes, as the method is applicable to any GSHP catalogue data.     

地源热泵道路融雪热水管可靠性设计研究

介绍了地源热泵(GSHP)技术在道路融雪中的应用,分析融雪热水管常规设计方法的局限性,通过对道路融雪影响因素随机分析,提出热水管可靠性设计方法,得到基于道路体热阻随机性和考虑管长变异性的热水管长设计公式。结合工程案例进行对比分析,研究表明,可靠性分析与设计方法在GSHP道路融雪应用中能够较好地协调经济性和功能性要求。     

内蒙地区垂直地埋管蓄热过程土壤温度的变化特性

给出了内蒙地区土壤温度计算式,通过计算获得该地区地表以下20m处土壤温度年波动范围为0.0483%。本文针对土壤蓄热过程建立了二维非稳态传热物理数学模型。基于有限元分析法对内蒙地区热泵长期(90天)连续蓄热过程进行了模拟研究。分析了钻孔口径、回填材料、地埋管管径及热流密度等因素对蓄热过程土壤温度特性的影响。研究表明:热泵长期连续运行会导致地埋管附近土壤出现热堆积不利于蓄热。热流密度、地埋管管径对土壤温度场和热作用半径影响较大;钻孔口径、回填材料对其影响较小;钻孔间距应保持在6.5m以上。研究结果对内蒙地区太阳能-地源热泵系统相关参数的设计具有重要指导意义。     

分析地源热泵岩土热物性参数影响因素与不确定性

地源热泵岩土热物性测试是一种三维的数学模型,这种数学模型的建立能够分析进行测试的时间,钻孔半径、岩体的温度、加热器的功率等都会影响到热物性参数。本文主要研究影响地源热泵岩土热物性参数的因素,供读者参考。     

超强吸水树脂与源土混合作为地源热泵供热系统回填材料的实验研究

在热泵制热工况下,超强吸水树脂与源土混合作为回填材料,分别对螺旋盘管、U型管以及整个系统进行了实验研究,得出系统性能变化曲线。实验结果表明,超强吸水树脂与源土混合作为回填材料,特别是螺旋盘管换热器,可明显增大地下换热器换热量,提高地源热泵系统的效率和稳定性,适用于干旱、土壤非饱和以及地下水位比较低的地区。     

SI住宅干式内装系统架空地面和地暖干式铺法施工技术

SI住宅干式内装系统架空地面施工技术是在地板下采用CP地脚螺栓支撑,架空空间内铺设机电管线。与一般的直铺地板相比,本方法地面温度相对较高,地面干燥,温度、湿度适中。在架空地板施工的基础上,实施地暖干式铺法施工。地暖干式铺法施工由基层聚苯乙烯泡沫板、中间层导热板及加热管、顶层水泥承压板组成,用尼龙胀塞与底层地面进行固定。将以前由工人在现场自由安装的管道敷设到预制好的衬板中,规整有序,同时减少施工过程中对材料的损坏。     

混合式土壤源热泵应用分析

土壤源热泵在冷热负荷有较大差异地区的应用会使土壤温度场恢复缓慢,导致热泵效率逐年降低,为此提出混合式土壤源热泵,对其组成结构、应用方式及控制策略进行分析与探讨。     

Performance assessment of a horizontal-coil geothermal heat pump

This paper evaluates the performance of a geothermal heat pump in Iran. An air-to-air 5.275 kW heat pump has been changed and redesigned to a geothermal heat pump system for the first time in Iran. Air-to-air condenser has been replaced by a tube-in-tube heat exchanger and assembled system has been tested under ARI-325 standard at the national energy lab of Iran and the results have been compared with the original system. Then, local weather conditions and soil properties of Tabriz (located at the north-west of Iran) have been applied and geothermal coil has been designed. Coil has been connected to the heat pump and the average coefficient of performance (COP) of rather more than three has been recorded in cooling mode. Results obtained from experimental measurements show that horizontal GSHP systems can be used for Tabriz-like climates in Iran. Copyright © 2006 John Wiley & Sons, Ltd.