Energy Efficient Air Conditioning System Using Geothermal Cooling-Solar Heating in Gujarat, India

It is well known that one unit of electrical energy saved is equal to more than two units produced. One way of economizing the power is utilization of energy efficient systems at all locations. In the present study, the air conditioning system is analysed and an innovative way is suggested. We use natural low temperature of shallow sub surface (1 - 3 m) of the earth—geothermal cooling system. It is known that majority of the households and the apartment complexes in India have two tanks for water storage. One is the underground water sump and the other is the overhead water tank. In our study, we use these two water storage systems for space cooling during summer and also for heating during winter. The main aim of our paper is air-conditioning of the space in an economic way to save electricity. It is based on a simple idea of transferring the low temperature from underground water sump to the room in the house using water as a mode of transport. Since India is a tropical country located at low latitude, most of the year, the air temperature is high and demands space cooling. However, for a couple of months during severe winter months (Dec.-Jan.) at Ahmedabad, heating of the space is required. For heating the space, we suggest to use the well-known solar water heater. Effective use of heat exchanger is shown through computation, modelling schemes and lab experiment. We recommend geothermal cooling for 10 months in a year and solar hot water system during 2 months of winter. It is observed that the ambient air temperature of 35°C - 40°C in the room can be brought down to 26°C without much consumption of electricity. In a similar manner, the room temperature at night (13°C) during winter in Ahmedabad can be increased to 27°C through circulation of water from solar water heater in the heat exchanger.

Analysis of the Thermal Performance on Cooling and Dehumidifying Process in Air Washer

On the bads of theory and experiment, this paper studies and analyses the factors such as water - air ratio, air velocity, spraying water pressure and initial water temperature, which affect the heat and mass transfer in air washer , thus can help us to reduce the power consumption and Improve the efficiency of heat and mass transfer.

A concept of capillary active,dynamic insulation integrated with heating,cooling and ventilation,air conditioning system

When a historic façade needs to be preserved or when the seismic considerations favor use of a concrete wall system and fire considerations limit exterior thermal insulation,one needs to use interior thermal insulation systems.Interior thermal insulation systems are less effective than the exterior systems and will not reduce the effect of thermal bridges.Yet they may be successfully used and,in many instances,are recommended as a complement to the exterior insulation.This paper presents one of these cases.It is focused on the most successful applications of capillary active,dynamic interior thermal insulation.This happens when such insulation is integrated with heating,cooling and ventilation,air conditioning(HVAC)system.Starting with a pioneering work of the Technical University in Dresden in development of capillary active interior insulations,we propose a next generation,namely,a bio-fiber thermal insulation.When completing the review,this paper proposes a concept of a joint research project to be undertaken by partners from the US(where improvement of indoor climate in exposed coastal areas is needed),China(indoor climate in non-air conditioned concrete buildings is an issue),and Germany(where the bio-fiber technology has been developed).

考虑变掺氧富氧燃烧与利用LNG冷能的LAES的综合能源系统低碳经济调度

为促进风电消纳,减少火电机组的碳排放,解决综合能源系统(Integrated Energy System,IES)低碳经济运行问题,文中引入变掺氧富氧燃烧技术对燃气机组进行改造,并结合利用液化天然气(Liquefied Natural Gas,LNG)冷能的液化空气储能(Liquid Air Energy Storage,LAES),提出了一种电热气冷IES低碳经济优化策略。首先,构建含变掺氧富氧燃烧燃气机组、利用LNG冷能的LAES、电转气(Power To Gas,P2G)设备、中央空调和溴化锂制冷机的IES架构,并建立各设备的数学模型;其次,引入阶梯式碳交易机制,建立了以系统运行成本最小为目标的电热气冷IES低碳经济调度模型;最后,采用MATLAB调用GUROBI求解器对多个场景进行求解,验证了文中提出的低碳经济优化调度策略可以提高系统的风电消纳、有效降低系统运行成本,实现碳减排。

Characteristic studies of heat sources and performance analysis of free-cooling assisted air conditioning and ventilation systems for working faces of mineral mines

High temperature heat hazard at mineral mine becomes more and more serious as the increase of mining depth.Heat sources at working faces of mineral mines are complex and are of different characteristics,presenting new challenges for air conditioning systems.In this paper,heat sources at four types of working faces are summarized and their characteristics are investigated.Based on this,simplified equations,which are linear with length of working faces,are proposed to calculate heat dissipation rates.So that the main heat sources of different working faces can be found,and cooling load of air conditioning systems can be calculated.Then,considering main heat sources of coal mines,a typical working face is designed to investigate performances of different ventilation systems and air conditioning systems.Simulation results show that segmented ventilation systems(SC)and heat shield assisted centralized ventilation systems(CCHS)can realize much better temperature distributions at working faces.However,cooling load can be greatly reduced for CCHS,when untreated air is supplied to the coal seam side.Based on this,free cooling assisted air conditioning systems are designed,and annual average energy efficiency ratio(EERann)of the systems are investigated and compared between direct evaporate cooling and indirect evaporate cooling(IEC).For SC,as compared with scenarios without free-cooling,IEC can increase EERann by 15%-23%and 22%-32%under Benxi and Datong ambient conditions,respectively.Besides,to ensure high EERann,CCHS is preferred and it is essential to increase thermal insulation of air ducts.

布雷顿循环冷端空冷换热器设计与变工况运行特性分析

作为布雷顿循环系统中的重要冷端部件,气体冷却器的性能对循环系统结构紧凑性和运行高效性有重要影响。分析了一种新型横流印刷电路板式换热器(printed circuit heat exchanger,PCHE)—板翅混合式气体冷却器的工作性能及影响因素,对该种换热器建立了一个数值计算模型,并编写MATLAB程序验证其可靠性;基于此,对该类冷却器进行了设计,其功率密度均在1 MW/m^(3)以上,属于紧凑型换热器;其次进行了变工况性能分析,给出了冷却器的压降和换热性能随循环工质和冷却空气进口状态的变化规律,并比较了布雷顿循环工质为超临界二氧化碳、氮气、空气时冷却器的换热特性和压降特性,结果表明,冷、热流体流量的改变对换热特性的影响最明显。研究结果对布雷顿循环空冷换热器的设计与运行具有参考意义。

合肥市某会展中心空调冷热源改造方案碳排放分析

空调系统碳排放是建筑能源消耗的重要一环,但空调冷热源系统选择通常从其初投资、运行费用等经济性角度分析,很少从碳排放角度分析其特点。利用实际改造项目,从碳排放角度分析不同冷热源方案的空调系统年碳排放量,为空调冷热源系统选择提供参考。结合合肥市某会展中心调研情况,提出四种空调冷热源方案,根据空调系统的年碳排放量分析不同冷热源系统方案的特点,为项目冷热源系统选择提供参考。

不同空调冷热源对建筑碳排放量的影响分析

随着我国各项建筑节能标准的更新,对于建筑碳排放量控制的要求越来越高,而空调冷热源系统是影响建筑碳排放的重要因素,且随着能源结构优化,区域电网的碳排放因子明显降低,冷热源系统电气化将是碳约束下主要的发展方向。运用eQuest软件对不同类型空调冷热源系统的运行能耗和碳排放强度进行了动态模拟和定量分析,发现冷热源系统的能源利用形式和区域电网的碳排放因子与供暖空调系统的碳排放量密切相关,对冷热源系统选择起决定作用。

上海市某超高层办公楼空调系统调适

通过详细检测上海市某超高层高档办公楼项目的空调供热系统和制冷系统的运行状况,确认了锅炉、冷水机组和相应水泵等设备运行使用中存在的问题。开展了空调系统调适,在不进行设备改造的情况下,通过整改设备运行问题和调整自控程序,解决了大楼冬季空调供热功能失灵的问题,并提高了制冷系统的节能性。根据新建和既有公共建筑机电系统调适项目的经验,提出几点建议,为其他项目空调系统的运行调适提供参考。

工业园区中央空调蓄冷蓄热数字模型应用研究

工业园区中,中央空调系统负荷一般为最大负荷,其冷、热、气等多重负荷汇集,耦合程度高,园区综合能源系统不能忽视其系统性作用。本文针对工业园区中央空调系统的设备单元,构建蓄冷蓄热数字模型,并将数字模型应用于实际中央空调系统,从而实现园区空调系统的经济运行,提高园区综合能源利用效率。

带热回收的通用与医用集成空调系统的监理控制要点

集成了医用空调系统的通用中央空调系统,由于管网交叉、模式切换、控制逻辑复杂,容易导致施工质量出现问题、调试效果不理想、运营过程易出故障等情况。尤其是增加了冷凝热回收后系统更加复杂。文章从监理的角度,系统、全面地梳理构配件、安装、调试和运营维护等环节的主要问题,通过将医用空调系统冷冻水由控回水改为控出水,有效稳定了水温;通过增加缓冲储水罐,有效解决了水流波动的问题。除了对模式切换的逻辑进行剖析外,还对板式换热器等构配件的控制逻辑进行分析。文章的创新之处在于利用BA(空调群控系统)制造最不利工况,对压差旁通阀进行调试,有效保证了系统运行的稳定性。运营维护过程中模式的参数设置和调整,不仅可以稳定系统,还可以减少浪费,同时对BA的参数设置问题进行了分析。

武汉某国际商务区暖通空调冷热源工程设计

武汉某国际商务区江水源能源站项目被评为湖北省2019年建筑节能示范工程,本文对该项目的暖通空调冷热源工程设计进行了介绍,阐述了采用可再生能源——江水为冷、热源、利用热泵技术为商务区提供空调用冷、热水的方案,介绍了冬季供冷的四管制设计思路,同时对空调水系统进行了设计,阐述了采用二次泵+一次泵变流量设计的合理性等;设计内容可为大规模商务区集中供冷供热的暖通空调冷热源系统设计提供参考。

动物房空调系统节能设计探讨(一)

针对动物房能量回收问题,在简要介绍溶液吸收式全热回收节能的原理、机组运行工况的基础上,以一实际设计案例出发,分析了该机组应用于动物实验室的优势和劣势,尝试性地从常规的显热回收转换为全热回收。

洁净手术室新风湿度的优先控制设计

分析某医院洁净手术室空调系统的设计,包括空调热湿负荷计算、送风量和新风量计算、手术室空气处理过程焓湿图分析等。经实际计算,表明洁净手术室夏季采用新风湿度优先控制,相比采用新风处理到室内焓值节能效果更好。同时,对洁净手术室内温湿度设定和冷热源设计进行探讨,表明手术室温湿度合理设定以及手术室冷热源合理设计,对手术室能耗影响显著。

Investigation on the Influence of Refrigerant Charge Amount on the Cooling Performance of Air Conditioning Heat Pump System for Electric Vehicles

The application of air conditioning heat pump(ACHP) in electric vehicles could lead to significant electrical power saving effect. As for an air conditioning heat pump system for electric vehicles, the influence of refrigerant charge amount should be investigated during the design phase. In this study, experimental method was employed to investigate the influence of the refrigerant charge amount on the performance of the ACHP system. The results showed that the refrigerant charge amount had different influence on the refrigerant properties at various locations within the system. The coefficient of performance and pressure-enthalpy diagram were calculated, and showed a close relationship with refrigerant charge amount under different compressor speeds. The degree of subcooling and the degree of superheating were recorded and the critical charge amount was determined by a typical practical test method. In addition, the critical refrigerant charge amount determined by the experimental method was also compared with two typical void fraction correlation models, and the model with consideration of two phase stream reaction of the refrigerant showed a good estimation accuracy on the critical charge amount.

Thermal Management of Vehicle Cabins,External Surfaces,and Onboard Electronics:An Overview

Reducing heat accumulation within vehicles and ensuring appropriate vehicular temperature levels can lead to enhanced vehicle fuel economy,range,reliability,longevity,passenger comfort,and safety.Advancements in vehicle thermal management remain key as new technologies,consumer demand,societal concerns,and government regulations emerge and evolve.This study summarizes several recent advances in vehicle thermal management technology and modeling,with a focus on three key areas:the cabin,electronics,and exterior components of vehicles.Cabin-related topics covered include methods for reducing thermal loads and improving heating,ventilation,and air-conditioning(HVAC)systems;and advancements in window glazing/tinting and vehicle surface treatments.For the thermal management of electronics,including batteries and insulated-gate bipolar transistors(IGBTs),active and passive cooling methods that employ heat pipes,heat sinks,jet impingement,forced convection,and phase-change materials are discussed.Finally,efforts to model and enhance the heat transfer of exterior vehicular components are reviewed while considering drag/friction forces and environmental effects.Despite advances in the field of vehicle thermal management,challenges still exist;this article provides a broad summary of the major issues,with recommendations for further study.

Application of the ground cooling system for rural houses air conditioning in northeastern China

This study developed an appropriate ground cooling system that can be used for indoor cooling during summers in rural houses in northeastern China.To apply this system,a traditional rural house was selected and a heat exchanger was designed(PE pipe,32 m in length),manufactured,and installed according to the cooling load(2206 kJ/h)of one room of the experimental house.According to the experiment,the temperature of Room 1 equipped with the cooling system was 3℃ lower than that of Room 2 without the ground cooling system during the same time period.The temperature reduction effect of this system was confirmed through this study.When the ground cooling system was used in rural houses in Northeast China,it was found that a burial depth of 1.5-2.0 m for the ground heat exchanger is appropriate for considering workability and frost line.The use of the ground cooling system for indoor cooling during summers for rural houses in the northeastern region of China would reduce not only environmental pollution and the use of fossil fuels but also ease farmers off a certain amount of financial burden.

某省电力调度通信楼数据机房空调系统设计

基于某调度通信楼数据机房的空调系统设计,探讨保证机房空调系统可靠性的措施以及降低系统运行能耗采用的自然冷却技术和余热回收技术。根据项目的实际运行情况,给出数据机房运行初期机柜上柜率较低情况的设计建议。

环境风影响下高压直流输电换流阀空冷平台换热性能研究

针对北方某换流站换流阀空冷平台,建立了包含换热器、风机、周围建筑及环境风等多种因素在内的三维传热流动数值分析模型,模拟研究了夏季主导风向下环境风对换热器入口空气温度、风机风量和换热量的影响规律,阐明了影响换流阀空冷平台换热性能的主导因素。结果表明:当环境风速由0 m·s^(-1)增加至12 m·s^(-1),空冷平台入口空气平均温度先升高后降低,在风速3 m·s^(-1)时极1、极2空冷平台风机入口平均温度最高,较环境温度分别升高了5.4℃与4.0℃;空冷平台下部负压随着风速的增加不断降低,导致风机入口风量持续减少,在风速12 m·s^(-1)时极1、极2空冷平台风机入口平均风量较无风环境分别降低了12%与8%;空冷平台的换热量随环境风速的增加呈现先降低后升高的趋势,环境风速3 m·s^(-1)时极1、极2空冷平台的换热性能衰减最为严重,两者换热量较无风环境分别减少了39%与29%;通过对影响换热量的主导因素分析,发现热风回流带来空冷平台入口温度的上升是导致换热量减小的关键因素。研究结果可为换流阀空冷平台的设计优化提供理论依据。