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.

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%.

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.

A Case Study:Distribution of Bacterial and Fungal Aerosols in Air-Conditioning Systems in Shaanxi History Museum

In order to investigate the bacteria and fungi aerosol characteristic distribution in HVAC-system and its components at Shaanxi History Museum.Measurements were performed to probe the bacteria and fungi aerosol in HVAC systems,located at Xi'an city,China.The results showed that there was fungi growth inside the ventilation ducts,fungi contamination was worse than bacteria,and both of them were distributed into occupied space with the air supply ducts.The dominating genera of fungi was found to be Penicillium spp.and Aspergillus spp.,which was respectively 46.1% and 20.7% in settling fungi,and the dominating genera of fungi in dust were Cladosporium spp.and Penicillium spp.,which was 41.8% and 30.1% respectively.It suggests that available measures to improve and control the performance of HVAC-systems such as the maintenance,management and cleaning should be taken to prevent this pollution and to develop strategies to keep this pollution away.

Study on the Elman Neural Network Operation Control Strategy of the Central Air Conditioning Chilled Water System

The stable operation of the central air conditioning water system always is a major difficulty for the control profession. Paper focus on the water system with multi variable, strong coupling, nonlinear, large time delay characteristics, presented use feed forward coupling compensation method, to eliminate the coupling effect between temperature and pressure. In this paper, the Elman neural network controller is designed for the first time, and the simulation results show that the response time of Elman neural network controller is shorter, the system is more stable and the overshoot is small.

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.

2020-2021年苏州市公共场所集中空调通风系统卫生状况

目的了解苏州市公共场所集中空调通风系统卫生状况。方法采用随机抽样的方式于2020年7—8月至2021年8—9月对苏州市区正常使用的38家次集中空调通风系统进行卫生监测,检测送风中PM_(10)、细菌总数、真菌总数、β-溶血性链球菌,风管内表面细菌总数、真菌总数、积尘量,冷却水中嗜肺军团菌,依据《公共场所集中空调通风系统卫生规范》(WS 394-2012)和《公共场所卫生检验方法》(GB/T 18204.5-2013)进行采样和检测。结果2020—2021年检测的38家次集中空调通风系统中,检测指标总体合格率为93.8%,各场所中宾馆酒店合格率最高,医疗场所合格率较低,差异有统计学意义(χ^(2)=11.87,P<0.05)。集中空调送风指标PM_(10)、细菌总数、真菌总数、β-溶血性链球菌合格率分别为97.8%、92.4%、76.1%、100.0%,各指标间差异有统计学意义(χ^(2)=41.81,P<0.05);风管内表面细菌总数、真菌总数、积尘量合格率为98.4%、89.5%、100.0%,各指标间差异有统计学意义(χ^(2)=20.42,P<0.05);冷却水中嗜肺军团菌检出率为10.5%。结论苏州市公共场所集中空调通风系统卫生状况总体较好,但真菌和军团菌污染需要加以关注。

中央空调负荷精细化调控双层优化技术研究

针对当前中央空调系统粗放式调节不能准确释放调控潜力的问题,深入分析中央空调各子系统工作原理与调控方式,提出基于双层优化的中央空调负荷精细化调控技术方案。首先,面向实际工程实践需求建立建筑湿热标度模型;然后,建立以舒适度和经济性优化目标函数为主的上层调控模型,采用Shapley值法对温湿设定值的进行分配;接着,建立以各子系统优化组合能耗最低为优化目标函数的下层调控模型,采用蚁群算法对优化目标函数进行求解;之后,通过求解双层模型,制定包括末端风机、冷冻水泵以及冷水机组等组件的精细化调控策略;最后,通过多个算例验证所提中央空调负荷精细化调控技术方案的正确性与有效性。

Strategy of constructing virtual peaking unit by public buildings’central air conditioning loads for day-ahead power dispatching

With the gradually widely usage of the air conditioning(AC) loads in developing countries, the urban power grid load has swiftly increased over the past decade.Especially in China, the AC load has accounted for over30% of the maximum load in many cities during summer.This paper proposes a scheme of constructing a virtual peaking unit(VPU) by public buildings’ cool storage central AC(CSCAC) systems and non-CSCAC(NCSCAC)systems for the day-ahead power network dispatching(DAPND). Considering the accumulation effect of different meteorological parameters, a short term load forecasting method of public building’s central AC(CAC) baseline load is firstly discussed. Then, a second-order equivalent thermal parameters model is established for the public building’s CAC load. Moreover, the novel load reduction control strategies for the public building’s CSCAC system and the public building’s NCSCAC system are respectively presented. Furthermore, based on the multiple-rank control strategy, the model of the DAPND with the participation of a VPU is set up. The VPU is composed of large-scale regulated public building’s CAC loads. To demonstrate the effectiveness of the proposed strategy, results of a sample study on a region in Nanjing which involves 22 public buildings’ CAC loads are described in this paper. Simulated results show that, by adopting the proposed DAPND scheme, the power network peak load in the region obviously decreases with a small enough deviation between the regulated load value and the dispatching instruction of the VPU. The total electricity-saving amount accounts for7.78% of total electricity consumption of the VPU before regulation.

基于决策树算法的冷冻水系统优化运行研究

以四川省成都市某办公建筑空气源热泵中央空调系统为研究对象,针对冷冻水系统制定夏季供冷工况下变冷冻水供水温度与变冷冻水流量相耦合的优化运行策略。首先依据运行数据确定出建筑负荷的主要影响因素;其次结合影响因素依据建筑负荷建立决策树算法,将系统运行工况分为7类;最后整理出每种分类工况下空调系统能效COPsys的分布情况,并以COPsys最高时对应的冷冻水供水温度和冷冻水泵设定频率作为该工况下最佳设定参数。结果表明:以上一年度的运行条件为基准,使用该运行策略在保证室内环境舒适度要求的前提下,夏季可以节约33%左右的电量,有效提升了中央空调系统的运行效率。

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。

模糊-PID控制器在空调温度控制中的应用

该文首先利用计算机仿真软件中的优化工具箱对常规PID控制器中的比例、积分和微分参数进行优化,并且针对中央空调温度控制系统非线性、大滞后的特点,设计了在规则上可调整的模糊控制器,该模糊控制器通过α因子自调整和Ku的自寻优,达到适应和跟踪系统参数变化的目的;而后采用模糊逻辑工具箱和MATLAB函数相结合,方便地实现空调温度控制系统的计算机仿真。仿真结果表明,这种控制方式控制效果优于常规PID控制,有效地改善了系统的动态性能、稳态精度和鲁棒性。

Experimental investigation of integrated air purifying technology for bioaerosol removal and inactivation in central air-conditioning system

In this research, high voltage static electricity and ultraviolet technologies were integrated to an air purifying device which can be used to trap and kill airborne bacteria and viruses in central air-conditioning systems. An experimental platform was built to mimic the central air system, in which the efficacy of the newly built device was examined. In addition to the standard physical and chemical tests, bacteriophages were used to simulate airborne viruses in the experimental system. The bacteriophage suspension was aerosolized into the air with ultrasonic wave atomization.The result showed that more than 86% removal efficiency of micro-particles (<10 micron in diameter) were removed after the device was in operation in a building and more than 95% of bacteriophages in the experimental system. It is concluded that the integrated air purifier is suitable for controlling air quality and preventing virus transmission through the central air system.

2015-2018年北京市怀柔区公共场所集中空调通风系统卫生状况

目的了解2015-2018年北京市怀柔区公共场所集中空调通风系统卫生状况,为制定今后监督和监测重点提供依据。方法依据《公共场所卫生检验方法第5部分:集中空调通风系统》(GB/T18204.5-2013)要求,对2015-2018年怀柔区42家公共场所集中空调通风系统的送风中细菌总数、真菌总数和β-溶血性链球菌、风管内表面细菌总数、真菌总数和积尘量、冷却水/冷凝水中嗜肺军团菌进行检测。结果2015-2018年共监测使用集中空调通风系统的公共场所42家,所有检测项目均合格的有27家。4年间集中空调通风系统合格率差异有统计学意义(Fisher’sχ2=235.21,P<0.001)。集中空调通风系统送风指标中,送风中细菌总数、真菌总数、β-溶血性链球菌总数的合格率间差异无统计学意义(χ2=6.84,P=0.145)。集中空调通风系统风管内表面微生物指标中,表面细菌总数、表面真菌总数和尘积量合格率差异无统计学意义(χ2=0.05,P=0.978)。所有公共场所的集中空调嗜肺军团菌监测结果均合格。结论2015-2018年怀柔区集中空调通风系统污染状况逐年改善,但无明显污染指标,须所有项目整体强化公共场所集中空调通风系统的定期清洗消毒工作,加强监管力度。

基于Double-DQN的中央空调系统节能优化运行

针对中央空调系统机理建模困难和参数辨识工作较为复杂的问题,提出了一种基于自适应建模和自学习机制的中央空调系统节能优化运行方法;设计了空调系统马尔可夫决策过程模型,采用具有双神经网络结构的强化学习算法解决学习过程中容易产生的维数灾难和值函数过估计问题.然后以广州市某办公建筑中央空调系统为研究对象,建立该系统的TRNSYS仿真平台,对算法的有效性进行了验证.仿真结果表明:该方法在满足室内热舒适性要求的前提下,以系统能耗最小为目标,实现了系统的节能优化运行;与PID控制和单神经网络强化学习控制方法相比,系统总能耗分别降低5.36%和1.64%,非舒适性时间总占比分别减少2.32%和1.37%.文中提出的强化学习控制器能够有效解决值函数过估计问题,具有良好的鲁棒性,自适应优化能力和较好的节能效果,可为建筑节能提供新思路.

基于S7-1200PLC的中央空调控制系统设计

针对传统中央空调的冷冻泵、冷却泵不能自我调节负载而造成的能源浪费问题,采用可靠的PID控制算法和变频技术,设计了由变频器、PLC、数模转换模块、温度传感器等器件构成的温差闭环自动控制系统,来自动调节水泵的输出流量,从而达到节能目的.设备改造试验结果表明,由S7-1200PLC控制器构成的温差闭环自动控制系统,能耗下降较为明显,实现了恒温控制,节约了企业设备改造成本.

大型集中空调水系统平衡调试技术探讨--以华晨宝马铁西工厂总装物流车间为例

以该工厂总装物流车间平衡调试工程为例,探讨了集中空调水系统不同形式管网的调试方法及调试过程中末端设备间的相互影响。结果表明:当系统各子回路安装自力式压差控制阀时,可对系统进行分区调试,以提高工作效率;对于调试工程而言,调试过程中自力式压差控制阀的压差设定在压差控制范围内时对整个管网的阻力无显著影响,但为保证系统的稳定性,应取控制范围的中间值;当自力式压差控制阀所控回路设备较少时,实测各设备间相互影响所引起的误差超过10%,不能忽略不计。

基于电能计量的中央空调冷量分摊方法

在国家“双碳”重大战略驱动下,中央空调系统逐渐成为助力国家节能减排的重要担当。为充分调动中央空调用户的节能积极性,提高中央空调分户计费精确性,该文在分析风机盘管供冷量与耗电量关系的基础上,提出了一种基于电能计量的中央空调分户冷量分摊方法。通过仿真比较得出,该方法在低投资情况下有效地提高了中央空调分户计量冷量分摊的精度,保证了空调分户计费的公平性,更好地促进国家中央空调分户计量任务的推广。

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。

全球环境问题与替代冷媒的选择——再评HCFC-123和HFC-134a在中央空调系统中的使用前景

根据新近研究成果介绍了臭氧层耗损与气候变暖的相互关联 ,列出了替代制冷剂修正后的环境特性参数与评价标准 ,介绍了蒙特利尔和京都两议定书之间的关系 ,评述了HCFC - 1 2 3的应用前景并陈述了作者的看法。