Fire protection and the interface with the HVAC system

Automatic activation of smoke control systems is accomplished by the building fire alarm system. The fire alarm system along with the automation system, are integrated to monitor and control the smoke control system. The principal components and operation of the two systems are described. In addition HVAC operating modes, are described as they relate to smoke control.     

Case studies in building smoke control

Smoke control systems for three buildings are described. Each of the buildings is low-rise three or four stories high. In each case a smoke control system using the HVAC system to limit or direct smoke migration from large portions of occupied space was used. Each of the buildings contained an interconnected space through the height of the building. One of the buildings uses a mall concept; the second, a modular concept of multiatria; and the third, a lobby concept. The results of smoke control tests for each building are presented. It was found that a building pressurization system with roof vents failed to satisfy the smoke control criteria of limiting smoke spread from one floor to another. The design was changed to provide exhaust fans at the roof, which were subsequently tested and performed satisfactorily. Tests of the lobby concept and of the multi-atria were satisfactory.     

华凯花园住宅小区供热空调设计

该小区为大型住宅小区,自建集中燃气锅炉房,作为暖通空调和生活热水热源,塔楼供暖系统分高低区,室内采用散热器供暖,分户热计量。冷源为水冷螺杆式冷水机组,住宅楼空调一期采用分体机,二期采用户式多联机,会所采用风机盘管加新风的集中空调方式,街面商业出租单元采用变频多联机。介绍了小区的暖通空调、自控和防排烟设计。     

北京国典大厦空调设计

该大厦是一座以商务办公为主的写字楼,对大厦的空调水系统、风系统、供暖系统、气流组织、防排烟系统和DDC自动控制系统的设计作了介绍;详细介绍了空调冷热源的选择,阐述了办公类建筑的暖通空调设计;简单介绍了公共建筑中厨房排风、排烟系统的设计,并对设计中的一些经验和教训进行了总结。     

A tool for integrated hvac,building, energy and control analysis Part 1: overview of QUICKcontrol

This paper describes a tool called QUICKcontrol. The new, simplified, yet extensively verified building model made an efficient integrated tool possible. The system simulation is done using simplified though accurate component models. A unique simulation tool resulted.Any building, any HVAC system, and any control strategy can now quickly be built up using a graphical user interface. The integrated building, HVAC and control problem is then solved iteratively. Energy balances for each component, and for the system as a whole, are obtained. HVAC systems and controls can now be designed, optimised, and commissioned with ease and confidence.The software has already been successfully verified by eight case studies. The results proved to be sufficiently accurate for design, as well as control and energy analyses. For example, energy predictions calculated each minute are generally within 10% of measured values, while zone temperatures are within 1°C for 90% of the time.A new user typically takes a day to master the use of the software. Computing time for a very involved building, HVAC system, and complex energy management controls is approximately 10 min on a 133 MHz Pentium PC with 16 MByte RAM and 40 time steps per h. It is thus easy and practical to investigate a range of alternative control strategies and demonstrate their financial advantages to clients.     

某城市商业综合体暖通空调设计

随着人民生活水平的提高,多元化的商业综合体大量涌现,其本身的特点也对暖通设计提出了更高的要求,如何合理的设置通风、空调及防排烟措施显得尤为重要。以某商业综合体暖通空调设计为例,围绕工程概况、设计参数、冷热源、空调系统、通风排烟系统等各方面进行了详细说明,并且介绍了一些必要的节能环保措施。希望通过对此工程实例的设计分析,为以后同类建筑的暖通空调设计提供有效的参考。     

民用建筑防排烟及通风空调系统防火设计中的几点问题探讨

针对民用建筑工程设计中遇到的防排烟及通风空调系统防火问题,分析了现行国家标准关于内走道排烟、通风空调系统防火阀设置、地下室及半地下室竖向疏散通道正压送风系统设置等的相关规定,并提出了个人见解。     

世茂锦绣长江酒店暖通空调设计

介绍了该空调系统的设计,包括冷热源、水系统、空调方式、通风及防排烟系统、自动控制系统.     

国家体育场暖通空调设计

介绍了国家体育场的暖通空调设计原则及空调冷热源、风系统、水系统、防排烟系统的设计。     

Development and validation of online models with parameter estimation for a building zone with VAV system

The energy consumption by building heating, ventilating, and air conditioning (HVAC) systems has evoked increasing attention to promote energy efficient control and operation of HVAC systems. Application of advanced control and operation strategies requires robust online system models. In this study, online models with parameter estimation for a building zone with a variable air volume system, which is one of the most common HVAC systems, are developed and validated using experimental data. Building zone temperature and zone entering air flow are modeled based on physical rules and only the measurements that are commonly available in a commercial building are used. Various validation experiments were performed using a real-building test facility to examine the prediction accuracies for system outputs. Using the online system models with parameter estimation, the prediction errors for all validation experiments are less than 0.28 °C for temperature outputs, and less than 84.9 m³/h for air flow outputs. The online models can be further used for local and supervisory control, as well as fault detection applications.     

广东科学中心空调设计

以节能为核心,介绍了广东科学中心的空调、通风、防排烟系统设计.详细介绍了大温差空调水系统和低温送风空调系统在该工程中的运用,并阐述了空调自控系统的特点.     

Experimental investigation on energy saving potential of smart HVAC unit

It is well known that ‘the energy can’t be created but could be saved’ and the energy resources are depleting at an alarming rate over the decades. The HVAC unit consumes 1/5th of the World’s electrical power consumption. Over the years several modifications have been made on the HVAC unit to save energy. This study implements the machine-to-machine interaction through Internet of things which reduces the human effort. The proposed system utilises the smart power controlling and modifying feedback systems from mobile phones integrated with human motion detectors. Due to the accurate feedback system, the room temperature can be maintained within the range of ±0.3°C. The experiment shows an interesting result that the power consumption of compressor can be reduced by 45% using the smart control HVAC unit. The client can also control the system through a web server which controls the actuators.     

Overview of HVAC system simulation

The paper gives an overview of heating, ventilation and air-conditioning (HVAC) system modeling and simulation. The categorization of tools for HVAC system design and analysis with respect to which problems they are meant to deal with is introduced. Each categorization is explained and example tools are given. Further, the paper summarizes current approaches used for modeling (i) HVAC components, (ii) HVAC control and (iii) HVAC systems in general. After giving an overview of solution techniques for HVAC system simulation, the paper provides suggestions on how one should select an HVAC modeling approach relative to the simulation objective at hand.     

某化工企业的暖通空调系统设计

介绍了该工程的冷热源、冷热水系统和防排烟系统的设计,重点阐述了空调及通风系统在爆炸性危险区域的应用以及BAS系统在该工程中的应用及其重要性,并总结了几点经验教训。     

Smoke management in office buildings

Design considerations for smoke control systems have been addressed by numerous researchers and practicing engineers. However, papers discussing the actual observed performance of smoke control systems are less frequently encountered. The following three papers address the testing of smoke control systems from two perspectives. First, suggested procedures for testing smoke control systems are described relative to test methodology, system parameters requiring evaluation, and measurement systems. Second, the performance of actual systems is described as observed in tests.     

篁园市场暖通空调及防排烟设计

分析了该市场暖通空调及防排烟系统的设计难点。介绍了为解决暖通空调及防排烟系统设计对大型市场商位布置及经营环境影响较大的问题所采取的措施,包括将服务于首层的空调机房设于地下室、服务于2层及以上各层的空调机房设于建筑周边并用设备走廊与商铺分隔,合理设置疏散通道,适当采用竖向排烟系统及通透式吊顶等。取得了较好的应用效果。     

Performance analysis of supply and return fans for HVAC systems under different operating strategies of economizer dampers

HVAC systems and associated equipment consume a relatively large fraction of total building energy consumption, a significant portion of which is attributed to fan operation. The operation of economizer dampers when installed can cause high energy consumption in fans if they are not functioning in proper and optimal manner. This will mainly be due to the potential high pressure drops through those dampers and associated high total pressures that should be developed by supply and/or return fans. It is then necessary to ensure that a proper strategy to operate optimally the economizer dampers is implemented with minimum fan energy use. The paper examines several operation strategies of the economizer dampers and investigates their effects on the performance of both the supply and return fans in HVAC system. It also discusses a new operating strategy for economizer dampers that can lead to lower fan energy use. The strategies are evaluated by simulations for a typically existing HVAC system. Several factors such as the building locations, system characteristics, resistance in the duct where the dampers are installed, supply air temperature and economizer control, and minimum ventilation requirements are also considered during the evaluations. The results show that the way of the economizer dampers been controlled has a significant effect on fan performance and its energy use. The proposed strategy if properly implemented can provide fan energy saving in the range of 5-30%, depending mainly on the number of hours when the system operates in the free cooling mode, damper characteristics, and minimum outdoor air.     

A methodology for integrated building— HVAC system thermal analysis

This paper presents an integrated methodology for thermal analysis of buildings and their HVAC systems. The methodology is based on the use of Laplace transfer functions for the buildings, its heating-cooling system and control components. These transfer functions can be used for building thermal control studies, frequency domain analysis and energy analysis. Laplace transfer functions for the building are obtained by means of thermal network models that include both distributed parameter elements such as thermal mass, lumped elements such as the room light-weight contents, and which represent radiant exchanges accurately. For detailed models for which an analytical solution is not feasible, the s-domain transfer functions are obtained through a modified least squares polynomial fit to the discrete frequency responses obtained by inversion of the system admittance matrix. Fourth order polynomials provide accuracies of approximately 1%. The methodology is applied to obtain both air temperature and operative temperature transfer functions. Laplace transfer functions are also used for HVAC system and control components. Transient thermal control studies are performed by means of an efficient numerical Laplace transform inversion technique. Building heating/cooling load calculations are performed by means of discrete Fourier series techniques.     

Optimization of air-conditioning system operating strategies for hot and humid climates

This paper describes research into the optimal operation of building heating, ventilation, and air-conditioning (HVAC) systems focusing on both temperature and humidity control. While most previous work on HVAC optimization has been limited to evaluation of conventional temperature-based control systems, this study emphasizes the humidity control issue in meeting both sensible and latent building loads. The analysis is based on a combination of a realistic simulation of a direct expansion (DX) air-conditioning system and a direct-search numerical optimization technique. The simulation models have been validated through comparisons with field data. Optimization was performed on five different system control variables to minimize system power consumption while meeting building loads and maintaining comfort. Indoor temperature and humidity are also optimized within standard comfort constraints. Building loads were modeled using an extended bin method that allows consideration of the interactions between loads and indoor conditions. Results indicate that minimum energy use typically occurs at low airflow rates, with indoor humidity levels below the upper comfort limit. Results also show that coil air bypass and evaporator circuiting control are typically not necessary unless operation would otherwise result in overcooling. The optimization results also translate to relatively simple strategies for system control. Significant savings are demonstrated over conventional control strategies used in packaged DX equipment.     

Application of optimization techniques on lumped HVAC models for energy conservation

Heating, ventilating, and air conditioning (HVAC) systems comprise nearly one third of annual household energy consumption in the United States. HVAC energy use can be reduced by applying controls. This study applies a novel control method on a system with arbitrary steady-state and transient load distributions. The new method uses multi-dimensional interpolation between optimized control configurations for various steady-state load distributions. Demonstration of the new method on a two-room HVAC system predicts power savings for an arbitrary steady load that is nearly equivalent to that using a Variable-Air-Volume (VAV) with chiller modulation. However, the new method provides better energy savings for arbitrary transient loads: 19% energy savings over an uncontrolled system compared to energy savings of 6% for a VAV with chiller modulation. The average transient temperature deviation from setpoint using the new method is slightly better than that using VAV with chiller modulation.