An Energy-Saving Control Strategy on Central Air-Conditioning System

An energy-saving control strategy based on predictive control for central air-conditioning systems is proposed in this paper. The cold load model is developed to describe the dynamic characteristics of temperature control systems, and then parameters in the cold load model and in the central air-conditioning system model are estimated. Generalized predictive control (GPC) is used to establish an optimization model to minimize the consumption of energy and the control error of temperature. The simulated annealing (SA) algorithm, combined with quadratic programming, is adopted to solve the optimal problem. Contrasted with the simulation of traditional PID control, the results prove the effectiveness of this proposed strategy.

Optimum Energy Management of the Central Air-Conditioning System in Intelligent Buildings

An optimum energy saving scheduling strategy of the central air conditioning system in an intelligent building (IB) was proposed. Based on the system analysis a set of models of the central air conditioning system was established. The periodically autoregressive models (PARM) based on genetic algorithms (GA) were used to predict the next day’s cold load. The improved genetic algorithms (IGA) with stochastic real number coding were used to finish the optimum energy saving scheduling of the system. The simulation results for the building of the Liangmahe Plaza show that the proposed strategy can save energy up to about 24 5%.

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.

Experimental Study of Energy-Saving Air-Conditioner with Hot Water

Energy-saving air-conditioner with hot water is an air source heat pump air-conditioner,which can also supply hot water.The hot water is heated by a double pipe condenser connected with an air-cooled condenser in series in the system.This experiment of the energy-saving air-conditioner was carried out in the enthalpy-difference air-conditioner laboratory.The hot water temperature and the compressor's discharge and suction pressure were recorded in the working condition,where the ambient temperature was at 43 ℃,35 ℃,21 ℃,7 ℃,and 2 ℃ separately.The results showed that the system operated stably and reliably.This system can supply 240 L hot water at 50 ℃ in the whole year,and its coefficience of performance(COP)is much higher than the conventional air source heat pump system.Its energy conservation was proved by comparing the thermal efficiency with other sourece water heaters.

Analysis and Modeling of the Central Air-Conditioning System in Intelligent Buildings

The central air conditioning system in an intelligent building (IB) was analyzed and modeled in order to perform the optimization scheduling strategy of the central air conditioning system. A set of models proposed and a type of periodically autoregressive model (PAR) based on the improved genetic algorithms (IGA) were used to perform the optimum energy saving scheduling. The example of the Liangmahe Plaza was taken to show the effectiveness of the methods.

Application of Dual Throttling Air-Conditioning System to Explosion-Proof Frequency Converter

An explosion-proof dual throttling air-conditioning system was put forward to solve the heat dissipation and internal dewing problems of explosion-proof frequency converter in the underground coal mine. This study investigated the feasibility and benefits of explosion-proof dual throttling cooling and dehumidification air-conditioning system applied to the explosion-proof frequency converter. The physical model of dual throttling air-conditioning system was established and its performance parameter was described by mathematical method. The design calculation of the system has also been done. The experimental result showed that the system reached the steady state at the refrigeration mode after running 45 min, and the maximum internal temperature of the flame-proof cavity was 31.0 ℃. The system reached the steady state at the dehumidification mode after running 37 min. The maximum internal relative humidity and temperature of the flame-proof cavity were 33.4% and 36.3 ℃, respectively. Therefore, the proposed system had excellent ability of heat dissipation and avoided internal dewing. Compared with water cooling system, it was more energy-saving and economical. The airflow field of dual throttling air-conditioning system was also studied by CFD simulation. It was found that the result of CFD numerical simulation was highly consistent with the experimental data.

EnergyPlus能耗分析软件在空调系统节能改造中的应用

介绍了EnergyPlus能耗分析软件,以某公共建筑1 000m2演播室空调系统的节能改造为工程背景,应用该软件对室内温度进行模拟,介绍了如何建立模型模拟室内温度场,根据模拟结果分析验证节能改造方案,为施工管理提供了理论依据和技术参考。

Design of Fuzzy Controller for Central Air Conditioner

A structure of central air conditioning system in building and its running pattern are proposed in order to perform optimum energy saving strategy. The design of room temperature controller is taken as an example to discuss the design of fuzzy controller using common microprogrammed control unit (MCU) in detail. Based on fuzzy theory the query control tables fixed in read only memory (ROM) of MCU are established to realize the energy saving in the room temperature controller and the reasoning procedure is analyzed. The diagram of hardware design and the flow chart of software of room temperature controller are presented. The results show that the proposed method is practical and effective to achieve the energy saving goal.

Heat Pump Technology Applies on Air-conditioners Impact on Electric Power

In recent years, power grid has been experienced in difficult times that there is a shortage of demand load among market, and more and more black out exited that bothered residents’ normal life. With the increment of energy consumption and power load, this problem will be more serious without any feasible solutions. Besides, the air conditioning system is the largest residential energy consumer. In this report, a GSHP air conditioning system has been illustrated and compared with the conventional air conditioning system currently used in Chengdu, Sichuan province, China. The benefits of using the GSHP system are not only on cost saving, but also energy saving and eco-friendly.

地铁站空调水系统节能控制研究

为了降低空调水系统的能耗,研究广州某地铁站的空调水系统节能控制策略。使用设备厂商提供的样本数据进行参数拟合,建立较为准确的设备模型,利用Trnsys软件搭建地铁站空调水系统模型。针对“大流量、小温差”现象,提出定温差控制策略,以降低水系统的能源消耗。结果显示:与定流量水系统相比,定温差控制策略下地铁站空调水系统节能率达到25.86%;在整个供冷季,相对于常规7℃的供水温度定温差控制策略,变冷冻水供水温度定温差控制策略的空调水系统节能约3.40%。

电动车废热辅助空调系统的研究

针对目前电动车空调存在的节能性和低温适应性等问题,提出了一种电动车废热辅助热泵空调系统。该系统将多变频器协调控制技术、双级压缩循环技术、废热辅助热泵技术有机融合,通过仿真分析研究系统在不同运行状态下的系统性能。仿真结果表明:协调调节低压级压缩机和风扇电机的频率,可实现系统制冷/制热量和能效比的优化控制;合理设置单双级压缩的温度切换点,能提升制热性能、保证系统在低温工况下的可靠运行;利用废热辅助空气源热泵技术,能实现系统的节能。研究结果为减小空调系统对电动车续航里程的影响、推动电动车的普及提供了参考。

纺织空调绿色生产技术途径

探讨纺织空调实现绿色生产的途径和方法。针对纺织空调运行能耗高、耗水量大的问题,以创建绿色工厂为目标,从提高设备能效、优化空调热湿处理方法、加强运行调试与能源管理等方面提出具体要求和措施,并提出了细纱车间热分流、热回收、送回风系统低能耗运行的方法。认为:做好纺织空调节能降耗工作有助于实现纺织车间绿色生产。

某调度通信楼空调系统节能减碳改造设计实践

重点介绍了某调度通信楼空调系统的节能减碳改造设计,通过综合运用余热回收、可再生能源、固体蓄热、高效制冷机房等多项技术,构建了安全可靠、绿色低碳、高效节能的空调系统。采用HDY-SMAD空调负荷计算及分析软件模拟了建筑物全年的空调能耗,并对优化前后空调系统的运行能耗和碳排放进行了测算。结果显示,优化方案空调系统全年节约电量100万kW·h,全年碳减排573 t,节能减碳效果显著。

通信机柜用空调热管一体化设备过渡季性能实测研究

为解决通信机柜传统空调能耗高、机柜内气流组织紊乱、基带处理单元(BBU)温控效果不佳等问题,研发了通信机柜用空调热管一体化设备,采用热管冷却为主、蒸气压缩式空调为辅的温控系统及下送上回、高风速、内循环的气流形式。机组应用于郑州某通信基站,经实地测试后,结果表明,在过渡季高温工况下,运行模式1调控BBU平均工作温度为38.2℃,最大出风温度为46.5℃,在过渡季常规工况下,运行模式2调控BBU平均工作温度为29.5℃,最大出风温度为41.3℃,均满足相关标准的温控要求,保证BBU安全运行。与通信机柜传统空调相比,空调热管一体化设备在运行模式1和2下,压缩机运行比例分别为24.9%和0,节能率分别为57.3%和71.9%,电能利用率(PUE)分别为1.43和1.19,过渡季综合节能率为71.3%、PUE为1.20。

北京某大型商场空调系统节能改造方案分析

大型商场人流量大、散热设备多、空调系统运行时间长,有较大节能潜力。调研了北京某大型商场空调系统的能耗情况,针对其运行过程存在的问题,提出了一套基于空调系统节能控制技术的综合节能改造方案。研究表明,该空调系统节能改造后,年节电量为140.56万k Wh,每年节省电费160.24万元;节热量为601.82GJ,每年节省供热费用5.95万元,节能效果与经济效益较好,可为北京地区类似公建节能改造提供借鉴和参考。

基于航班信息确定旅客数模型联动空调节能技术研究

针对机场航站楼内空调系统能耗高且节能潜力巨大的特点,提出一种基于航班信息动态预测分时段分区旅客数,进而联动优化空调节能控制的新方法。新方法研究重点在于航站楼空调调控分区的划分、航班信息有效数据的提取、分时段分区旅客数模型的构建、节能档位控制的实现策略与步骤。结合华南地区某支线机场航站楼冷源及空调末端控制的实际测试数据进行模拟分析,结果表明,在保障旅客舒适度的基础上,通过分区旅客数精准调控空调系统运行模式,实现了能耗较大幅度的降低,节能成效显著,为航站楼空调节能技术提供了新的思路,为同类型其他机场提供了参考。

中央空调系统制冷机组节能优化

空调系统是公共建筑中重要的基础配套设施,其能源消耗占据较大比重,在节能降耗方面存在巨大潜力。为实现在满足冷负荷需求的条件下达到中央空调系统总运行能耗最小的目标,建立了中央空调系统制冷机组能耗模型,并将室外湿球温度和实时的冷负荷值作为空调系统能耗模型的输入条件,分别利用粒子群算法和改进粒子群算法获得在不同负荷需求时空调系统对应的最佳工作点,实现中央空调系统运行优化节能的效果。

溶液调湿空调在医药厂房工程应用的碳减排潜力分析

众多医药生产车间要求低湿环境,需要送风含湿在7 g/kg甚至5 g/kg以下,常规7℃冷冻水驱动的冷冻除湿方式难以完成上述除湿任务,因而医药厂房通常采用转轮除湿系统对空气进行湿处理以满足环境热湿控制需求。然而,转轮系统所需再生温度较高,通常使用高温蒸汽或电加热器作为再生热源,限制了系统的低碳化运行。溶液空调系统具有利用低品位冷热源的优势,但现有研究对于溶液空调技术在医药建筑中应用可行性研究尚不充分,无法揭示其在医药建筑应用的节能减排潜力。因此,现场测试了溶液空调系统在某试点医药厂房的实际应用效果,对比了其与常规转轮系统的性能差异并阐明差异原因。示范工程应用结果表明,一次回风系统送风含湿量在6 g/kg左右时,溶液系统可以将再生热源温度从100℃以上降至50℃以下,相较于常规转轮系统的节能比率为15%~45%,典型工况下的碳减排率为20.7%。以期为医药建筑低碳化发展提供经验参考与数据支撑。

数据中心间接蒸发冷却复合空调系统的节能运行分析

结合上海地区的气候条件,采用TRNSYS软件,通过设定数据中心机房条件模拟出全年所需冷负荷随时间的变化规律,确定设备选型,并基于间接蒸发冷却复合空调系统主要设备的数学模型搭建了仿真平台。通过对空调系统运行模式的切换,模拟得到3种运行模式下的送风状态图及运行特性。结果表明,冬季应采用能耗更低的干模式,过渡季采用湿模式,夏季采用混合模式。对比常规机械制冷系统,复合空调系统的全年耗电量为352.6万kW·h,节能率高达34.8%。

太阳能吸收式制冷系统及其蓄能技术研究

在分析国内外现有太阳能吸收式制冷系统的基础上,从太阳能集热器、蓄能形式、辅助热源、吸收式冷水机组以及太阳能集热器与吸收式冷水机组的匹配等方面详细阐述太阳能吸收式制冷系统及其蓄能技术的发展现状,并对太阳能制冷空调系统的控制策略、优化分析及理论研究进行总结,最后指出太阳能吸收式制冷系统及其蓄能技术的发展方向。