地热直供结合燃气吸收式热泵供暖系统的应用分析

介绍了地热直供结合燃气吸收式热泵系统的工作原理。结合工程实例,对燃油锅炉和地热直供结合燃气吸收式热泵两种供热热源的技术和经济性进行了比较和分析。各采暖期的实际运行数据表明,采用地热直供结合燃气吸收式热泵作为供热热源具有明显的节能效果和经济效益。     

地热资源的开发利用及可持续发展

地热资源作为一种新型能源矿产,具有分布广泛、易于开发等特点,其利用方式主要有地热发电和地热直接利用两种.我国具有良好的地热资源条件,主要为中低温地热资源.据计算,我国12个主要沉积盆地的地热可开采资源量为7500×1018J,相当于2560×108t标煤.当前,我国地热资源利用方式主要以供暖、洗浴、种植等直接利用为主;地热发电发展缓慢,主要分布在西藏;利用热泵技术开发地热资源得到了快速发展;油区地热资源的开发利用也取得了良好的经济和社会效益.但同时我国地热资源产业也面临着一些问题,包括大部分地区尚未开展地热资源勘查评价,影响了地热资源规划的制订及地热产业的发展;防腐、防垢技术还需要进一步加强研究;地热回灌率普遍过低;增强型地热系统研究有待加强等.为了促进地热资源的可持续发展,建议在加大地热资源勘查力度的同时,应以浅层地温能和热水型地热资源为主,发挥热泵技术的优势,开展地热资源的综合利用及梯级利用;重视和加快油气区地热资源的利用;在西藏等适宜地区加大高温地热能发电利用;集中全国优势技术力量,在一两个有利区域开展增强型地热系统技术探索;此外,走回灌开发道路是地热资源开发利用的必然选择.     

土壤源空调系统全年运行设计与计算分析

采用贝塞尔函数求解了U型埋地换热器在稳态和正弦波边界下的解析解,可计算给定全年动态负荷下埋地换热器内流体温度,并据此判断埋地换热器的设计能否满足建筑物的要求.给出了在不同因素影响下流体全年最高温度和最低温度与U型管单位长度设计取冷(热)量的关系曲线,可用于指导U型埋地换热器的设计.得到了建筑物全年累计耗热量和耗冷量、最大热负荷和冷负荷应满足的关系,可用于指导建筑物冷热源方案的搭配.     

Design and development of a 10-kWe ORC installation working with low-temperature sources

This paper presents results of the experimental study for a 10-kWe Organic Rankine Cycle (ORC) unit that has been designed and developed in order to study its performance when solar or geothermal sources are used. A boiler was used to simulate those conditions and adjustments were made to generate the final heat by a solar or geothermal source in the same pace, size and way, which accurately reflects the operation of each system. R134a was selected as the working fluid. Measurements for key parameters at various points of the cycle were conducted and performance assessment was attempted. Based on the system operation under the conditions that were applied, and considering the various seasons of the year, it was found that the ORC unit working with low-temperature sources is likely to act as a complementary recovery system of heat quantities as the efficiency is rather small, but able to support other systems.     

竖埋螺旋管地热换热器理论模型及实验研究

对竖埋螺旋埋管地热换热器建立了传热模型，分析了流量、土壤传热系数对热输出的影响，并计算了等效传热系数、竖埋螺旋埋管换热器对土壤温度场的影响情况。在理论计算的基础上，对一竖埋螺旋管地源热泵系统进行了实验研究，对比分析了理论计算值和实验测试值，并分析了热泵系统的性能。     

高效利用地热水的系统型式及其经济分析

讨论了解决当前地热水严重浪费问题的几种技术方案。分析了三种系统型式：用于普通热水锅炉给水的系统；有蒸气锅炉和溴化锂吸收式热泵的复合系统；有电动蒸汽压缩式热泵的系统。证明地热水供热系统中使用热泵具有节能与经济意义。     

地下水流动对地下埋管换热器影响的实验研究

为确定地下水渗流对竖直地下埋管换热器的影响,该文从实验角度出发,分别对无渗流土壤、饱和土壤中地下埋管换热器热负荷对其周边土壤温度场的影响,有渗流土壤中地下水流速、土壤初始温度以及埋管热负荷对土壤温度场的影响进行了实验,从而得出在夏热冬冷地区或亚热带地区应用土壤源热泵时,宜采用冷却塔-土壤源热泵混合系统形式或将地下埋管换热器埋设在地下水流速较大地区,以期土壤源热泵的长期良好运行。     

Development and assessment of geothermal-based underground pumped hydroenergy storage system integrated with organic Rankine cycle and district heating

This study develops a geothermal-based underground pumped hydroenergy storage system (UPHES) integrated with an organic Rankine cycle (ORC) and district heating. The ORC has been integrated into the system for contributing the power demand of the pump used during the charging period to pump the water from the underground to the upper reservoir. District heating has been performed by geothermal. Heat recovered from the ORC has been used for the preheating of water used in district heating before entering the upper reservoir. With this proposed integrated system, both the peak energy demand has been shifted to off-peak hours and district heating has been performed. An ORC has also been included in the system to contribute to the energy demand of the UPHES pump. In order to evaluate the system's performance, thermodynamic analysis has been performed base on energetic and exergetic efficiencies. In the base case study, 60 MWh of electricity has stored by the UPHES. Also, a 2.8 MW of heating demand of 100 houses has been met and a 1.7 MW of power has been generated by the ORC. The power of the UPHES pump has been calculated as 6.81 MW. The efficiency of the UPHES system is 73.34%. Overall energy and exergy efficiencies of the proposed integrated system have been calculated as 93.09% and 78.37%, respectively.     

用遗传规划方法辨识地热热泵系统模型

进行了地热热泵系统的变频调节试验,并采用遗传规划方法去解决该系统的辨识问题。由检验数据可知,最大平均误差在7％以内,基本符合工程要求。这说明用遗传规划的方法辨识地热热泵系统是可行的。     

变温热源地热热泵系统的可用能分析

地热能作为一种新能源已成为许多国家的研究重点，如何提高地热能的利用率是其重要的研究方向，而热泵又是其中一项关键技术。本文针对地热热泵系统的变温热源，从减小可用能损失的角度进行了详尽的理论分析。首先，对该地热热泵系统中的各个主要部件进行了可用能分析，发现和能损失情况均与循环工质的性能有关；其次，在实际工况下比较了纯工质和非共沸混合工质的可用能损失情况；最终提出了几种有可能应用于实际地热热泵工况下的循环工质。     

CO2跨临界低温地热源水-水热泵的实验研究

研究用CO2跨临界循环热泵系统开发低温地热资源，详细介绍了CO2跨临界循环热泵系统的运行机理、装置特点、热源选取。通过低温地热源的模拟实验，给出实验最优工况的调节方法，这对开发应用CO2热泵系统用能效率有着重要作用。     

GIS-supported mapping of shallow geothermal potential of representative areas in south-western Germany—Possibilities and limitations

The increasing interest in the utilization of shallow geothermal energy comes with the wish for better knowledge about the factors influencing its efficiency. For this purposes we focused on the subsurface condition's influence on the use of borehole heat exchangers (BHEs) coupled with a heat pump for heating purposes, since this is the most popular heat-extracting technique. We created maps showing the potential for this technique provided by the thermal underground properties. Therefore, we established an underground model for two study areas in south-western Germany with different geological settings using a geographic information system (GIS). The subsurface has been divided into layers with similar thermal properties based on geological, hydrogeological and lithological information. The layers have been attached with specific heat extraction values, according to the German VDI guideline 4640. For depths of 50 and 100 m, the weighted mean value of the specific heat extraction was calculated and presented within maps. These maps point out how the heat-extraction potential differs within and between the study areas and how it depends on depth.     

深层地埋管换热器换热性能模拟及稳定性研究

以深层地源热泵地埋管换热器为研究对象,对其换热特性进行数值模拟和实验研究。建立考虑轴向地温梯度的深层地埋管换热器传热模型并进行模拟计算,通过示范工程现场测试数据验证该模型的正确性。对深层地埋管换热器换热的性能稳定性进行研究,发现深层地埋管换热器连续长期运行及间歇长期运行下换热性能基本稳定。当按不同运停比运行时,岩土温度恢复效果良好。研究结果表明深层地源热泵有较好的换热性能及运行稳定性,为深层地热能的开发利用提供了新思路。     

A study on the optimized control strategies of geothermal heat pump system and absorption chiller‐heater

The world is becoming increasingly interested in renewable energy including geothermal energy. The utilization of geothermal systems is currently low because geothermal systems and existing source systems are used independently, but the supply rate of a geothermal system is increasing. Therefore, suggesting efficient operation plans and evaluations of the energy consumption and efficiency of a geothermal system is needed. This paper reports the results of a field study and survey of the present applications and operation conditions of a geothermal system. In addition, this paper proposes an efficient operation strategy for a geothermal system and compares this operation strategy with an existing operation strategy through simulation. The problems of existing operation condition were found out through a field study, and alternatives were proposed. The improvements were evaluated using the transient systems simulation program. And it would be possible for the reduction of the energy consumption through the comparative analysis of equipment efficiency and energy consumption. The result of analyzing the proposed combination header method through simulations compared with existing operation conditions can increase the use of geothermal systems, but the combined cooling and hot water of a geothermal heat pump and existing thermal source system reduced the efficiency of the heat pump. As a result of simulation on individual load‐sharing method, efficiency of geothermal system is increasing compared with the combination header method. This method was especially made to separate geothermal system's water loop and existing thermal source system's water loop. Copyright © 2013 John Wiley & Sons, Ltd.     

苏尔士增强型地热系统的开发经验及对我国地热开发的启示

增强型地热系统是采用人工形成地热储层的方法,从低渗透性岩体中经济地采出相当数量深层热能的人工地热系统。法国苏尔士（Soultz）地热项目已有20多年开发研究历史,但前人尚未对开发过程中的关键问题进行深入探讨,对其成功经验也未进行系统总结归纳。本文通过回顾其发展历程,总结该项目在钻井、储层激发、水力循环测试和储层监测方面的成功经验,同时提炼出地热开发中遇到的储层建设和井下泵设备等方面的问题,并指出数值模拟在地热开发过程应用方面的启示。苏尔士地热项目开发吸取了其他早期地热田的经验和教训,成功地建造了商业规模的人工激发储层,产生了大量的科研成果和先进技术,对后续开发的地热项目有重要指导意义。     

Thermodynamic analysis of a hybrid geothermal heat pump system

A thermodynamic analysis of a hybrid geothermal heat pump system is carried out. Mass, energy, and exergy balances are applied to the system, which has a cooling tower as a heat rejection unit, and system performance is evaluated in terms of coefficient of performance and exergy efficiency. The heating coefficient of performance for the overall system is found to be 5.34, while the corresponding exergy efficiency is 63.4%. The effect of ambient temperature on the exergy destruction and exergy efficiency is investigated for the system components. The results indicate that the performance of hybrid geothermal heat pump systems is superior to air-source heat pumps.     

水热型地热资源地球化学勘探技术研究进展

地球化学勘探技术在水热型地热资源勘探中的应用研究具有较长的历史,迄今已形成了一套基于气体与元素指标的勘探技术体系,涵盖了众多技术指标,且已在世界各地诸多地热田勘探研究中获得了广泛应用。结果揭示,在预测地热田发育有利部位、估算深部热储温度以及推断地热水来源等方面,地球化学勘探技术都可发挥其特有的作用,是一种经济有效的地热勘探技术,具有良好的应用前景。但地热地球化学勘探技术也面临其自身的局限性,其应用研究不仅受地热田类型的限制,而且目前主要集中于已知地热田上方的验证性研究,技术本身的多解性也较强。因此,在地热地球化学勘探技术完善与应用研究方面,还有待进一步深化。     

Geothermal‐based hydrogen production using thermochemical and hybrid cycles: A review and analysis

Geothermal‐based hydrogen production, which basically uses geothermal energy for hydrogen production, appears to be an environmentally conscious and sustainable option for the countries with abundant geothermal energy resources. In this study, four potential methods are identified and proposed for geothermal‐based hydrogen production, namely: (i) direct production of hydrogen from the geothermal steam, (ii) through conventional water electrolysis using the electricity generated through geothermal power plant, (iii) by using both geothermal heat and electricity for high temperature steam electrolysis and/or hybrid processes, and (iv) by using the heat available from geothermal resource in thermochemical processes. Nowadays, most researches are focused on high‐temperature electrolysis and thermochemical processes. Here we essentially discuss some potential low‐temperature thermochemical and hybrid cycles for geothermal‐based hydrogen production, due to their wider practicality, and examine them as a sustainable option for hydrogen production using geothermal heat. We also assess their thermodynamic performance through energy and exergy efficiencies. The results show that these cycles have good potential and attractive overall system efficiencies over 50% based on a complete reaction approach. The copper‐chlorine cycle is identified as a highly promising cycle for geothermal‐hydrogen production. Copyright © 2009 John Wiley & Sons, Ltd.     

Correlations for cost of ground‐source heat pumps and for the effect of temperature on their performance

Ground source heat pump systems are becoming more and more popular, even though their high initial cost is an obstacle to their wider penetration of the heating and cooling market. The purchase of the heat pump itself is one of the dominant costs, and the heat pump selection also influences the operation costs through its coefficient of performance (COP) value. However, few studies are available on this topic. Based on 23 water–water heat pump models available on the market, a correlation was developed to estimate their purchase cost as a function of the nominal cooling load of the heat pump. These heat pumps can be used in geothermal applications as well as in other heating, ventilating, air conditioning and refrigeration (HVAC&R) systems. The correlation is valid for a nominal cooling load between 20 and 841 kW. The nominal COP of the heat pumps was found to have virtually no effect on their purchase costs. Also, two correlations were developed to relate variations of cooling power and COP to the temperature levels on both sides of the heat pump. The heating mode is also considered. The correlations are useful to estimate the required nominal size of a heat pump given design operating conditions and to optimize ground source heat pump systems from a techno‐economical standpoint. Copyright © 2014 John Wiley & Sons, Ltd.     

Coupling of geothermal heat pumps with thermal solar collectors

The study discussed relates to the design and development of a process consisting of combining a reversible geothermal heat pump with thermal solar collectors for building heating and cooling and the production of domestic hot water. The proposed process, called GEOSOL, has been installed in a 180 m² private residence in 2004. This installation is the subject of long-term experimental follow-up to analyse the energy-related behavior of the installation at all times of the year. In addition, different configurations of this combined system (geothermal heat pump and thermal solar collectors) have been defined and will be simulated numerically using TRNSYS software. A comparative analysis of these different alternative versions will be conducted to determine the best configuration(s) of the GEOSOL process in terms of energy, economical and environmental performances.