数码涡旋多联式空调系统冬季运行特性实测

研究了数码涡旋多联式空调系统的冬季运行状况和节能性能,分析了影响系统小时平均供热性能系数HHPF的主要因素,得到了系统HHPF随室内机开机率、室外环境温度和室内设定温度的变化规律以及数码涡旋多联式空调系统部分负荷运行特性。通过计算每个工况点压缩机运行容量百分比,分析了室内机开机率和室外环境温度对压缩机运行容量百分比的影响。     

数码涡旋多联式空调系统冬季以空气源热泵制热运行的实验研究

实验研究了数码涡旋多联式空调系统冬季以空气源热泵制热运行时的运行特性,分析了室内设定温度一定时室外干球温度变化对室内机和系统的小时制热量、机组的小时耗功量及系统的小时供热性能系数HHPF的影响.     

Effects of double skin envelopes on natural ventilation and heating loads in office buildings

The influence of natural ventilation on heating load and energy savings in a building with a double skinned envelope (DSE) was examined in this study. Field measurements and computer simulations were performed under various weather conditions. The DSE was effective for saving energy and creating natural ventilation rates under clear and partly cloudy skies. Due to insufficient irradiance, the DSE was not effective for reducing the heating load under overcast sky conditions. When natural airflow rates from the cavity space between internal and external skin to the indoor space were controlled, the southwest-facing DSE effectively reduced heating loads due to the accumulation of solar irradiance.Regression models showed that outdoor air temperature was the most significant factor governing variations in cavity temperature under all sky conditions. Computer simulations indicated that natural ventilation was practical at an appropriate supply temperature only when the sky ratio was less than 0.7. The airspace in cavity of the DSE provided additional natural ventilation rates to the indoor space and effectively reduced heating loads. Natural ventilation was available for 135 h during three winter months without consuming additional energy to heat the outdoor air. The heating load was reduced by the DSE ranged from 17.98% to 18.7% depending on the airflow control options for the cavity space.     

天津地区某高层办公楼能耗模拟与节能潜力分析

建筑能耗中供暖空调能耗所占比例约为55%,是实现建筑节能的关键。采用DeST-c模拟了天津地区某新建高层(20层)办公楼能耗,将模拟结果与传统负荷计算结果进行了对比,同时分析了空调系统的风系统和水系统分别采用排风热回收和变流量技术后的节能潜力。对比分析表明与传统负荷计算方法相比,能耗模拟软件计算的全年累计冷热负荷值分别减少43.0%和31.0%,全年累计冷热负荷指标仅为传统负荷计算值的21.0%和26.0%。风系统采用排风热回收技术后,冷水机组总容量从1 800 kW降到为1 500 kW,全年制冷能耗节省5.3万kW·h;水系统采用变流量水系统技术后,理论上每年节省2.5万kW·h能耗。采用排风热回收和变流量两项节能措施后,空调系统总能耗降低约8%,节能效果明显。     

温湿度独立控制空调系统和常规空调系统的性能比较

选择北京和广州相同的办公楼作为比较对象,常规空调系统采用典型的风机盘管+独立新风的形式。应用DeST软件计算了建筑全年逐时冷负荷,计算了两个系统的能效比EER(energy efficiency ratio)和能耗。结果表明,对于北京的办公建筑,温湿度独立控制空调系统全年能耗为14.75k Wh/m2,EER为4.5;常规空调系统全年能耗为18.63k Wh/m2,EER为3.6。对于广州的办公建筑,温湿度独立控制空调系统全年能耗为32.66k Wh/m2,EER为4.5;常规空调系统全年能耗为43.39k Wh/m2,EER为3.4。相比常规空调系统,温湿度独立控制空调系统的节能率在20%～30%。     

蒸发冷却空调新风系统的全年应用研究

结合干热、严寒或寒冷地区全年气候特点及冬夏季建筑能耗特性,通过逐时新风能耗模拟计算,得到设置热回收装置的全年用蒸发冷却空调系统冬季新风节能量远大于夏季节能量,选用热回收装置时应重点关注冬季热回收效率,各类热回收装置中转轮热回收装置全年节能量最大,节能效果最好。基于此,深入分析了蒸发冷却空调系统冬夏季新风加湿需求、新风量变化范围和水系统管径选择,给出了全年用蒸发冷却空调机组冬季运行的防冻措施。     

某办公楼空调系统能耗模拟

利用DeST软件对各区域全年逐时冷热负荷与空调系统的能耗进行了模拟计算,分析了不同窗墙面积比、遮阳构件对能耗的影响,确定南向窗墙面积比为0.34,由外挂石材形成的遮阳构件可降低全年累计冷负荷指标约2.18％.     

关键区温度重设定的自适应按需新风控制

针对多区域变风量空调系统,提出一种关键区温度重设定的自适应按需新风控制策略,以最少的能耗满足各区的室内空气质量要求。该策略实时检测各区人员负荷,识别关键区,充分考虑关键区的新风需求,在进行新风设定时充分考虑循环空气中没有使用完的新风。关键区的温度重设定可以加大输送到关键区的送风量从而加大关键区的新风量,新风比减小,从而达到节能目的。利用多区域变风量空调系统的动态仿真平台对该控制策略进行了测试,对其动态控制性能、能耗特性及空气质量特性进行了评估,同时将该控制策略与其他按需新风控制策略进行了比较。     

关于完善公共建筑集中空调系统节能评价体系的一些探讨

认为目前的节能评价体系用"年空调总用电量"、"单位空调面积耗电量"不能全面、正确地评价集中空调系统。提出了新的集中空调能效自动跟踪评价系统,该系统对集中空调系统的实时制冷量、各空调用电设备的实时功率、实时用电量、实时能效、历史平均综合能效、实时负荷率、历史平均负荷率等数据进行跟踪、监测、统计并显示。以工程实例说明新的评价系统的应用。     

Modeling solar-driven ejector refrigeration system offering air conditioning for office buildings

A lumped method combined with dynamic model is proposed for use in investigating the performance and solar fraction of a solar-driven ejector refrigeration system (SERS) using R134a, for office air conditioning application for buildings in Shanghai, China. Classical hourly outdoor temperature and solar radiation model were used to provide basic data for accurate analysis of the system performance. Results indicate that during the office working-time, i.e., from 9:00 to 17:00, the average COP and the average solar fraction of the system were 0.48 and 0.82 respectively when the operating conditions were: generator temperature (85 °C), evaporator temperature (8 °C) and condenser temperature varying with ambient temperature. Compared with traditional compressor based air conditioner, the system can save upto 80% electric energy when providing the same cooling capacity for office buildings. Hence, the system offers a good energy conservation method for office buildings.     

Optimal supply air temperature with respect to energy use in a variable air volume system

In a variable air volume (VAV) system with 100% outdoor air, the cooling need in the building is satisfied with a certain air flow at a certain supply air temperature. To minimize the system energy use, an optimal supply air temperature can be set dependent on the load, specific fan power (SFP), chiller coefficient of performance, outdoor temperature and the outdoor relative humidity. The theory for an optimal supply air temperature is presented and the heating, ventilation and air-conditioning (HVAC) energy use is calculated depending on supply air temperature control strategy, average U-value of the building envelope and two outdoor climates. The analyses show that controlling the supply air temperature optimally results in a significantly lower HVAC energy use than with a constant supply air temperature. The optimal average U-value of the building envelope is in practise mostly zero.     

石家庄采暖室外计算温度的变化分析

采暖室外计算温度的合理确定直接影响采暖设计热负荷的计算准确度,进而影响暖系统的热舒适性、能耗及投资情况.采用更接近实际情况的室外计算温度,会提高建筑节能分析研究、设计和运行的精确度,有利于促进建筑节能技术的发展.在分析石家庄冬季气温变化特点及发展趋势的基础上,比较现行国家规范GB50172-93<民用建筑热工设计规范>和河北省DB13(J)63-2007<居住建筑节能设计标准>分别给出的石家庄采暖室外计算温度参数.并与2007、2008年度采暖期室外温度实际情况进行一致性对比分析.结果表明,河北省DB13(J)63-2007<居住建筑节能设计标准>提供的石家庄采暖室外计算温度更为接近当前的实际情况,更有利于提高建筑节能设计质量.     

Double cooling coil model for non-linear HVAC system using RLF method

The purpose of heating, ventilating and air conditioning (HVAC) system is to provide and maintain a comfortable indoor temperature and humidity. The objective of this work is to model building structure, including equipments of HVAC system. The hybrid HVAC model is built with physical and empirical functions of thermal inertia quantity. Physical laws are used to build the sub-model for subsystems that have low thermal inertia while the empirical method is used to build the sub-model for subsystems with high thermal inertia. The residential load factor (RLF) is modeled by residential heat balance (RHB). RLF is required to calculate a cooling/heating load depending upon the indoor/outdoor temperature. The transparency, functionality of indoor/outdoor temperatures and simplicity of RLF makes it suitable for modeling. Furthermore, the parameters of the model can be calculated differently from room to room and are appropriate for variable air volume (VAV) factor. Nowadays, a VAV system is universally accepted as means of achieving both energy efficiency and comfortable building environment. In this research work, a pre-cooling coil is added to humidify the incoming air, which controls the humidity more efficiently inside conditioned space. The model presented here is verified with both theoretical and numerical methods.     

空气源-水环复合热泵空调系统能耗研究

介绍了水环热泵空调系统辅助热源的形式,提出了采用空气源和电加热作为辅助热源的空气源-水环复合热泵空调系统,研究了不同室外温度时建筑不同内外区冷热负荷比下该系统的能耗,分析了循环水温对系统能耗的影响,比较了该系统与采用电热锅炉和燃煤锅炉的传统水环热泵空调系统的一次能耗。     

Experimental study on a residential temperature-humidity separate control air-conditioner

According to the temperature and moisture characteristics and current problems experienced in the Yangtze River Area, a temperature-humidity separate control air conditioner was developed. This unit can remove indoor sensible heat and latent heat load separately, and adjust indoor temperature and humidity respectively, thus improve indoor comfort and reduce energy consumption. The air-conditioner consists of an air cooling evaporator and a water cooling evaporator. Orthogonal experiments were designed to study the influence of outdoor temperature, indoor temperature, indoor humidity, compressor frequency, and refrigerant distribution ratio in air cooling evaporator (RDRAE) on the unit performance. The results showed that the dehumidification capacity ranged from 0 to 4.02 kg/h; the EER ranged from 2.71 to 4.57; the cooling capacity ranged from 6822 to 13,080 W. The results can help to make the control logic of the unit, and be used as the basis of energy consumption calculation. Units with temperature and humidity separate control could save about 15.6% of the cooling energy consumption against traditional residential air-conditioner, and 47.8% against the traditional residential air-conditioner that could control both indoor temperature and humidity.     

上海地区独立住宅分布式光伏发电系统的后评估研究

基于上海一独立住宅光伏发电系统运行一年的数据,从发电量、光伏系统效率、光伏能源替代率、光伏系统效率影响因素等方面进行后评估。结果表明:过去一年度理论预测年发电量为5 738 k W·h,实际发电量为4 109 k W·h,全年度光伏系统效率为73%。为研究光伏系统效率的影响因子,在系统运行期间未对光伏组件表面实施人工清洁维护,对此条件下的运行数据进行分析发现,光伏系统效率总体呈现逐渐降低的趋势。其中在近水平安装角度的情况下,组件光电转换效率最大降低达2.08%。在该住宅按照现行理想的设计条件运行(冬季连续采暖确保室内20℃、夏季连续空调确保室内26℃)的前提下,过去一年度的总用电量为12 054 k W·h,其中空调用电量为9 332 k W·h,占到总用电量的77.4%。全年光伏能源替代率为34%,过渡季节可实现光伏能源替代率最高达180%。独立住宅上存在较大的节能空间和光伏能源替代率提升空间。     

Application of a closed-loop oscillating heat pipe with check valves (CLOHP/CV) on performance enhancement in air conditioning system

The objective of this paper was to study the application and working fluid type of a closed-loop oscillating heat pipe with check valves on energy consumption in split type air conditioning system. In the experiment, the CLOHP/CV was fabricated from the copper tube with the diameter of 2.03 mm. In the usual range of 20-27 °C indoor design temperature and 50% relative humidity. R134a, R22 and R502 refrigerant was used as working fluid in the CLOHP/CV set for this study. In comparison of the type with a conventional air conditioning system and that with the CLOHP/CV air conditioning system, the results have shown that; the new cooling load had increased 3.6%, the latter gave the highest value of 14.9%, 17.6% for COP and EER, respectively. The highest value of heat flux was 5.19 kW/m² with R134a was used as the working fluid, at overall operating temperature. The results of this study are expected to guideline as they improve the performance of the air conditioning system in buildings, which reduce its energy consumption.     

如何确定发电机房通风降温时的室外计算温度

按一般设计理念,关于室外计算温度的确定原则,如进行空调设计时,采用空气调节室外计算干球温度;如进行通风设计时,采用通风室外计算温度;如进行采暖设计时,采用采暖室外计算温度.不同目的设计形式,采用不同的室外计算参数.但是,对于常年全负荷运行的发电设备而言,如果机房内是采用通风换气降温时,不能错误的采用夏季室外通风计算温度...     

深圳市6栋写字楼集中空调系统逐时冷负荷与能耗分析

以深圳市6栋高层写字楼集中空调系统全年运行数据为依据，分析了写字楼集中空调系统制冷主机逐时输出的冷负荷及年运行能耗，得到了各楼主机全年输出的逐时冷负荷的最大值，分析比较了各大楼的建筑面积、入住率、单位空调面积负荷、单位空调面积空调能耗，并比较了各楼的主机选型方案。     

提高空调采暖系统能效比对实现重庆市居建节能65%目标的影响分析

本文通过实例工程的模拟计算,讨论了提高空调采暖系统能效比对能耗的影响及节能潜力分析,初步分析了从新空调准入能效比的规定下达到节能65%目标时对围护结构热工性能的要求。