Adaptive HVAC zone modeling for sustainable buildings

Control of energy flows within a building is critical to achieving optimal performance of heating, ventilation and air-conditioning (HVAC) systems. To design optimal HVAC control strategies, a dynamic model of the HVAC system - particularly the building zones that it services - is essential. As analysis of building energy consumption is facilitated by the accurate prediction of indoor environmental conditions, techniques that dynamically model HVAC zones are crucial, and as such, is an active area of research. This paper focuses on real-time HVAC zone model fitting and prediction techniques based on physical principles, as well as the use of genetic algorithms for optimization. The proposed approach is validated by comparing real-time HVAC zone model fitting and prediction against the corresponding experimental measurements. In addition, comparison with prediction results using an algorithm based on feedback-delayed Kalman filters has demonstrated the superiority of the proposed approach in terms of prediction accuracy.     

Use of nanoparticles to make mineral oil lubricants feasible for use in a residential air conditioner employing hydro-fluorocarbons refrigerants

The application of nano-fluids in refrigerating systems is considered to be a potential way to improve the energy efficiency and reliability of HVAC&R facilities and to make economic the use of environment-friendly refrigerants. In this paper, we report a method that uses nanoparticles to enhance the energy efficiency of retrofitted residential air conditioners (RAC) employing HFCs as alternative refrigerants. The reliability and performance of RAC with nanoparticles in the working fluid have been investigated experimentally. A new mineral-based nano-refrigeration oil (MNRO), formed by blending some nanoparticles (NiFe₂O₄) into naphthene based oil B32, was employed in the RAC using R410a as refrigerant. A method showing how to disperse the NiFe₂O₄ nanoparticles in the mineral oil refrigeration lubricants is presented together with an investigation of their stability. The solubilities of the new MNRO in R134a, R407C, R410a and R425a were measured. The performances of the RAC, such as the cooling/heating capacity, the power input and the energy efficiency ratio, were determined. The results indicate that the mixture of R410a/MNRO works normally in the RAC. The cooling/heating EER of the RAC increased about 6% by replacing the Polyol-Easter oil VG 32 lubricant with MNRO.     

交通银行上海分行营业大楼空调安装调试的若干问题

以一空调工程为例,着重介绍了空调系统调试过程中经常出现的一些问题,如送风不足、堵塞、噪音大、风口结露以及保温等,并分析其原因,提出解决办法。     

外冷型多级蒸发制冷空气处理机组性能分析

介绍了该机组的空气处理过程。机组夏季出风参数主要与进风参数、进水温度、风水比、直接蒸发制冷段效率有关。在分析影响因素的基础上,绘制了机组在不同地区应用时的夏季出风参数图,并给出了机组出风参数确定的一个实例。计算了机组的夏季性能参数。     

表冷器水路设计方法

表冷器系用于组合空调的换热设备,其性能的好坏可决定空调系统的设计能否实现.现国内大多数厂家的表冷器设计都不尽合理,表冷器长度变化有4倍之多,但其水路只有一种,新风回风工况水路也无分别.时常有如下情况出现进出水温差很小或很大,实际换热量达不到标称值,排水不畅冬季冻坏等各种问题.本文提供的设计方法使上述问题均迎刃而解.     

模糊控制器在中央空调控制系统中的应用

分析了中央空调系统的特性，并对其各个部件建立数学模型，基于MATLAB环境下，利用simulink和fuzzy工具箱，对空调系统采用PID控制与模糊控制器的仿真比较，通过仿真结果显示，空调系统采用模糊控制具有较强的鲁棒性，波动小等优点。     

基于Fisher判别分析法的空调系统传感器故障诊断

为了对空调箱的温度和流量等传感器的故障进行诊断，提出了一种基于统计学的方法：Fisher判别分析法。该方法利用多元统计的方法对选取的故障样本进行训练和投影，使各个故障的样本在相应的空间分离，最后利用马氏距离法计算检测点投影与各故障样本投影的马氏距离，从而判断其故障类型。检验结果表明，该诊断方法效果很好。     

变风量空调系统机组部分的建模与仿真

本文针对变风量空调系统存在耦合,难以稳定运行的情况,把空调系统分解为机组部分和末端部分来考虑。对机组部分采用最小二乘法建模,并提出了基于单神经元自适应PID控制方案。应用Matlab软件对其进行仿真,仿真结果令人比较满意,证明了这种控制策略的可行性。     

卷烟厂变风量空调系统风阀控制方案探讨

空气处理机组风阀控制的传统方法是将新风阀、回风阀、排风阀三者的开度进行开度匹配联动控制。但是在空调系统的实际运行中发现,采用这种控制方法在某些情况下会引起室外新风通过排风阀倒灌进入空调机组中,从而影响室内的空气品质和空调的节能运行。本文研究了这种现象的原因,并提出了一种能避免这种现象的新的风阀控制方法。这种新的风阀控制方法只将回风阀和排风阀进行开度联动控制,在空调运行过程中,新风阀一直处于全开状态。本文最后通过现场实测结果证明了新的风阀控制方法的改进效果。     

香港海港城空气处理设备(AHU)的能耗测试及节能分析

通过对香港海港城空调系统中具有代表性的AHU运行特性的测试，对其运行能耗进行评价分析，并提出节能改进建议。