台湾办公建筑冬季蓄能混合式地源热泵空调节能潜力分析

系统整理了台湾各地的平均地温,重点研究冬季蓄能混合式地源热泵(STES-HyGCHP)系统在台湾办公类建筑中的运行策略与节能潜力。在夏季和过渡季节的部分时间用地埋管取代冷却水塔,在冬季通过冷却水塔和地埋管联合运行带走土壤积蓄的热量并储存"冷"能,可解决土壤热容失衡问题也可提高空调主机效率。经过eQuest模拟和全年逐时迭代计算,在台南应用混合式地源热泵系统,模拟案例的全年空调系统耗能最高可降低5.85%,利用尖峰和离峰电价差,可实现电费降低7.44%,在台北这两项数值分别为3.21%和4.71%,并证实该系统为具备可持续运行的能力。地下水流动的影响和经济性在文中并未涉及。     

热电厂凝汽器循环冷却水余热利用供热技术

介绍热电厂凝汽器循环冷却水常规余热利用供热技术。对吸收式热泵机组与吸收式换热机组(吸收式换热机组将热水型吸收式热泵与板式换热器相结合,替代热力站的传统换热机组)联合供热方式的技术经济性进行了分析。     

Experimental analysis of energy recovery for humidity control in split A/C system

This study presents a proposed idea about making use of the thermal energy rejected by the condenser in a water-cooled split-air-conditioning systems to decrease the relative humidity of the cold air supplied by such air conditioners. Most of split air-conditioner systems cool air without controlling its humidity. An amount of heat is rejected from the air conditioner, through the condenser, into the surrounding in order to allow the refrigerant to cool down and condense, thus, part of the lost energy can be exploited to decrease the relative humidity of the sub-cooled air that leaves the evaporator as saturated humid air. Four variables, viz. the coil type (single or double), the amount of flowing water, water, temperature, and the cooled air velocity were studied to find out the optimum conditions required for this purpose. The requisite amount of heat that may adjust the relative humidity of the conditioned air was also determined. The experimental results suggest an optimum design of a heat exchanger for performing the use of the heat rejected from the condenser to achieve the aim. As a result, the proposed heat recovery concept can be worthily adopted to achieve economic results in large-scale systems.     

高效全自动管道清洗系统在某集中冷站中的应用分析

广州地铁某集中冷站冷水机组采用珠江水作为冷却水源。在使用过程中,出现了机组传热温差急剧上升、经常故障报警和电能消耗异常等情况。为解决此问题,通过分析比较,安装了3套适合冷水机组冷凝器的全自动清洗系统CQM,实现了冷水机组高效、节能、环保运行。     

空调用蒸发式冷凝器能耗实验研究

当室外气温较高时,风冷热泵系统冷凝器存在换热效果下降的问题,而蒸发式冷凝器可以改善此问题,蒸发式冷凝器因此逐步得到广泛重视。为研究采用蒸发式冷凝器制冷系统的能耗情况,通过正交实验的方法,对比研究了蒸发式冷凝器与风冷式冷凝器在相同工况下压缩机能耗情况,并对影响其性能的因素进行了分析。研究表明,各因素对压缩机耗功量的影响能力依次为:冷凝器进口空气温度、速度及冷凝器喷水量。压缩机耗功量随进口空气温度的升高、进风空气速度降低而增大,随喷水量增加存在先减小后保持不变的现象。     

LCNG加气站冷热电三联供系统的应用研究

简述了国内外对LCNG冷能利用的研究及应用现状,设计了一种LCNG加气站冷热电三联供系统,该系统包括LCNG气化站系统和冷热电三联供系统。LCNG气化站系统包括LNG储罐、抽风机、LNG-冷媒换热器以及CNG压缩机;冷热电三联供系统包括冷媒-制冷剂换热器、冷媒储罐、发电机、废热回收装置、充电桩。LNG通过管道依次连接抽风机、LNG-冷媒换热器、冷媒储罐、冷媒-制冷剂换热器,再通过制冷循环将冷量传递到室内。本系统的有益效果是:LCNG气化站系统耦合冷热电三联供系统,实现能量梯级利用;天然气用于发电,产生的电能供充电桩使用,利用废热回收装置收集发电产生的热量,用于预热燃烧室入口端的天然气,提高发电效率;利用废热回收装置收集的热量加热LNG,使之转变为天然气,替代水浴式加热器的使用,起到节能的效果;本系统可以与传统的石化加油站结合,实现"油气电非"的综合使用。     

A new method of determination of indoor temperature and relative humidity with consideration of human thermal comfort

A new method is described in this article for selecting indoor temperature and indoor relative humidity to achieve minimum energy consumption for a required indoor thermal comfort level which is evaluated with indoor effective temperature. This method is derived from a central air-conditioning system and is based on our investigation that under a same indoor effective temperature, the system cooling load and the system energy consumption increase with an increase of indoor temperature. As such, energy consumption cannot be reduced with increasing indoor temperature for a given human thermal comfort level. In order to reduce energy consumption while keeping a same indoor thermal comfort level, indoor temperature and relative humidity may be determined with the proposed method described in this article. With the proposed method, a parameter variation study has also been conducted, which suggests that for a given indoor effective temperature, a combination of high indoor relative humidity and low indoor temperature be generally taken. The proposed method is based on the central air-conditioning system; yet it can be easily extended to other systems.     

浅谈燃气发电厂如何实施清洁生产

文章通过对某燃气发电厂实施安装投入运行溴冷机、改造增压机控制系统、改造厂房冷却水回收系统、改造余热锅炉尾部加装换热器、实现余热再利用等清洁生产的技术措施,实施小指标考核等清洁生产的管理措施,取得较好的节能降耗效果。这些措施为同类企业实施清洁生产提供了经验,并为企业降低能耗指标提供了技术支持。     

太原市某集中供热换热站的节能运行

以太原市某集中供热换热站的运行调节为例,将水泵变频控制技术应用于两个换热站的二次网循环水泵上,分析了2007年～2011年四个采暖年度的运行工况特点,总结了变频调速控制技术的应用,指出了利用二次网循环水泵变频技术是降低换热站能耗的有效手段,从而达到节约能源、减少环境污染的目的。     

中央冷水主机变冷冻水温对系统节能的影响分析

受室外气象条件等因素影响,建筑中央空调系统冷水机组长时间处于非设定工况条件下运行,导致部分工况冷负荷和冷凝器入口水温均低于设计工况,从而对建筑设备运行能耗影响较大。冷冻水水温的重设,是解决这一问题的主要途径之一。然而,对于传统的中央空调系统调节方式,冷冻水出水温度重新设置所产生的节能是针对定冷冻水流量,且提高LCHWT在降低冷水机组运行能耗的同时,还会增加泵的运行能耗。为此,本文针对变冷冻水水量的冷水机组,对上述问题进行了理论分析和计算,并引入实际案例进行验证分析。本方法可为优化建筑设备运行调节方式,降低建筑设备运行能耗参考。     

中山大学附属肿瘤医院节能改造分析

分析了医院冷热源系统存在的问题,针对问题严重的燃油锅炉进行改造,并建立了能源管理系统,统一控制协调太阳能集热系统、双效热回收热泵系统以及各循环水泵、换热器,以最大程度地提升能源的利用率。并对改造前后系统能耗进行对比,改造后每年可节省260.5万元运行费用,可节省标煤926 t,对周围环境改善作出了巨大贡献。项目力争成为广州市既有建筑改造示范工程中的样板性示范工程。     

区域供冷系统最佳供冷面积探讨

对于容量已确定的热电厂，为实现热电冷联供，可以根据集中供冷区域空调负荷的特点，利用总能耗最小的原则，确定区域供冷系统最佳供冷面积，以便充分利用区域供冷系统优势，实现节能目的。     

Methodology for optimizing the operation of heating/cooling plants with multi-heat-source equipments

A methodology for optimizing the operation of heating/cooling plants with multi-heat-source equipments is proposed. The methodology decides the optimal combination of the running machines to minimize the energy consumption of a heating/cooling plant. The energy consumption, energy cost and carbon dioxide emission are simulated using a tool developed in the MATLAB^® Simulink^® environment, embedded with a module developed using MATLAB^® Stateflow^® that can automatically decide the on/off states of heat source machines corresponding to cooling and heating loads and an operational priority order of heat source machines. A case study is introduced to demonstrate the methodology, which is an actual heating/cooling plant located in Osaka, Japan. The plant consists of two absorption chiller/heaters, one centrifugal chiller, one ice chiller, and two air-source heat pumps. The proposed methodology is used to simulate the plant performance at six different operational priority orders of heat source machines. The best operational combination can reduce primary energy consumption by 19.7%, energy cost by 12.8%, and carbon dioxide emission by 29.6%, compared to present operation.     

Experimental investigation of dehumidification process in cooling coil by utilizing air-to-air heat exchanger in humid climate of Iran

Energy recovery systems can be used in HVAC to reduce energy consumption by recovering wasted energy from the exhausted air to pre-cool inlet fresh air. In this paper, experimental study of utilizing cooling coil (CC) and cooling coil combined with heat exchanger (CCHE) has been developed. Considering the different climate zones in Iran, the experimental study has been done for the areas with high humidity content. In each case, the effects of air-to-air heat exchanger (HE) on the sensible and latent cooling load are investigated. The analysis gives the applicability of HE in Iran for various operational conditions to obtain air with lower moisture content. In CCHE systems more latent load quota is allocated in cooling coils and lower air humidity ratio can be obtained. Also in the cities with higher dew point depression (difference between dry-bulb and dew point temperature) more humidity reduction is achieved and the difference between latent load quotas of CCHE system is higher than CC system.     

Economic benefits of optimal control for water-cooled chiller systems serving hotels in a subtropical climate

A water-cooled chiller system in an air-conditioned hotel can take up about one-quarter of the total electricity consumption and considerable amounts of water in the heat rejection process. This paper evaluates operating cost savings of a chiller system integrated with optimal control of cooling towers and condenser water pumps. A sophisticated chiller system model was used to ascertain how different control methods influence the annual electricity and water consumption of chillers operating for the cooling load profile of a reference hotel. It is estimated that applying load-based speed control to the cooling tower fans and condenser water pumps could reduce the annual system electricity use by 8.6% and operating cost by 9.9% relative to the equivalent system using constant speed fans and pumps with a fixed set point of 29.4 °C for cooling water temperature control. The ways to implement this advanced control for system optimization are discussed.     

Effect of mass recovery evaporator temperature and condenser temperature on the performance of a solar adsorption-based desalination plant

Water scarcity increases alarmingly as the population increases. Over the years, a number of salt water desalination techniques have been proposed and reached limitations. The requirement of minimum energy is very well satisfied by an adsorption system, since it can operate with low-grade energy and waste heat exhaust from most industries. The first part of this work discusses the effect of condenser and evaporator temperatures on the performance of silica-gel adsorption cycle mathematically. The second part discusses the performance variations due to mass recovery in the two-bed adsorption system mathematically. It was found that the reduction in condenser temperature and increase in the evaporator temperature both increase the fresh water productivity and cooling capacity of a plant. A desalination plant with mass recovery assistance is superior in performance than the conventional plant. Portable water productivity of 8?m³/day/ton is achieved with the condenser temperature of 15°C and the evaporator temperature of 30°C.     

Energy saving through evaporatively cooled condenser air in conventional air-conditioning units

A theoretical study of the feasibility of evaporative cooling of the condenser air of a conventional vapour compression air-conditioning system to upgrade the rating of an air-cooled air-conditioning unit and consequent energy saving in the Delhi climate is presented. A brief review of the heat rejection option in an air-conditioning unit has been given and a theoretical background analysis for evaporative cooling of condenser air has also been presented. For illustration, one specific air-cooled package unit, whose performance characteristics as given by the manufacturers are available, has been used for calculations. Temperature variation data for New Delhi in the months of May and June 1991, obtained from the Meteorological Department, has been used. With the basic data, the upgradation of cooling capacity, power requirement and average energy consumption with and without evaporative cooling of condenser air has been calculated and the reduction in peak load and saving in the average energy consumption was predicted. Typical calculations of the water requirements for pre-cooling of condenser air were also predicted and compared with the corresponding requirements for water-cooled and evaporative condensers. It is concluded that there is an excellent and exciting possibility of reducing energy consumption (and consequent enhanced energy saving) in air-conditioning at national level.     

新型排风能量回收装置的分析与研究

作者从全铝制板翅式换热器与凝结水间接蒸发冷却联合应用的试验获得的结果出发，对该换热器应用于集中空调系统的能量回收做出了计算，并且进行较为详尽的分析，计算结果表明全新风空调系统使用该能量回收装置后，可以节省机组装机容量50％，节省运行费用一半；这对需要大量新风的厂房，医院的特殊病区等有很好的节能效果；而普通的舒适性空调系统，应用该能量回收装置后也可以节省装机容量20％；这表明在集中空调系统中应用全铝制板翅式换热器既能改善室内空气品质又能回收排风能量，是集中空调系统节能和人性化行之有效的措施：     

Energy savings potential of a desiccant assisted hybrid air source heat pump system for residential building in hot summer and cold winter zone in China

In hot summer and cold winter zone in China, air conditioning system has four running modes yearly including cooling with dehumidification, cooling, dehumidification and heating in residential buildings. The conventional air source heat pump (ASHP) system is not designed to independently control temperature and humidity, and is not very suitable for the dehumidification mode in the view of building energy consumption. A novel ASHP system combining radiant cooling/heating for residential buildings was presented. The main feature of this hybrid ASHP system is that desiccant wheel and cooling coil accomplish dehumidification process together, and the regenerative heat needed by the desiccant wheel is supplied by the condenser dissipated heat. Based on simulation studies and performance analysis, this paper predicts the primary energy consumption of the hybrid ASHP system in comparison with the conventional ASHP system during the cooling and heating seasons. It was found that primary energy requirement can be reduced by more than 8% in cooling with dehumidification mode, by 50% in dehumidification mode, and by more than 14% in heating mode. The study results prove that the hybrid ASHP system can keep great energy saving and running cost saving yearly, especially in the dehumidification process.     

Simulation and analysis on thermodynamic performance of surface water source heat pump system

This work established a thermodynamic performance model of a heat pump system containing a heat pump unit model, an air conditioning cooling and heating load calculation model, a heat exchanger model and a water pump performance model based on mass and energy balances. The thermodynamic performance of a surface water source heat pump air conditioning system was simulated and verified by comparing the simulation results to an actual engineering project. In addition, the effects of the surface water temperature, heat exchanger structure and surface water pipeline transportation system on the thermodynamic performance of the heat pump air conditioning system were analyzed. Under the simulated conditions in this paper with a cooling load of 3400 kW, the results showed that a 1 °C decrease in the surface water temperature leads to a 2.3 percent increase in the coefficient of performance; furthermore, an additional 100 m of length for the closed-loop surface water heat exchanger tube leads to a 0.08 percent increase in the coefficient of performance. To decrease the system energy consumption, the optimal working point should be specified according to the surface water transportation length.