双级耦合热泵在寒冷地区高层建筑中应用的模拟分析

分析了寒冷地区高层建筑供暖空调的特点,提出了四种可供高层建筑使用的、以空气为低位热源的双级耦合热泵系统。选择一幢写字楼,以空气源热泵+热泵型水冷VRF系统为例,通过建立数学模型,模拟分析了该系统在寒冷地区代表城市的运行特性,并与传统的低温空气源热泵系统进行了经济性比较。     

Low-temperature baseboard heaters with integrated air supply – An analytical and numerical investigation

The functioning of a hydronic baseboard heating system with integrated air supply was analyzed. The aim was to investigate thermal performance of the system when cold outdoor (ventilation) airflow was forced through the baseboard heater. The performance of the system was evaluated for different ventilation rates at typical outdoor temperatures during the Swedish winter season. Three different analytical models and Computational Fluid Dynamics (CFD) were used to predict the temperature rise of the airflow inside the baseboard heater. Good agreement between numerical (CFD) and analytical calculations was obtained. Calculations showed that it was fully possible to pre-heat the incoming airflow to the indoor temperature and to cover transmission losses, using 45 °C supply water flow. The analytical calculations also showed that the airflow per supply opening in the baseboard heater needed to be limited to 7.0 l/s due to pressure losses inside the channel. At this ventilation rate, the integrated system with one air supply gave about 2.1 more heat output than a conventional baseboard heating system. CFD simulations also showed that the integrated system was capable of countering downdraught created by 2.0 m high glazed areas and a cold outdoor environment. Draught discomfort in the case with the conventional system was slightly above the recommended upper limit, but heat distribution across whole analyzed office space was uniform for both heating systems. It was concluded that low-temperature baseboard heating systems with integrated air supply can meet both international comfort requirements, and lead to energy savings in cold climates.     

Influence of building parameters and HVAC systems coupling on building energy performance

The performance of different HVAC systems varies when coupled with different buildings. This paper examines the relationship between building heating and cooling load and subsequent energy consumption with different HVAC systems. Two common HVAC systems in use throughout the UK office building stock, variable air volume (VAV) system and fan coil (FC) with dedicated outside air system, have been coupled with a typical narrow plan office building with and without daylight control and for both cellular and open plan.The results presented in this paper clearly indicate that it is not possible to form a reliable judgment about building energy performance based only on building heating and cooling loads. For the two investigated systems, variable air volume system and fan coil with dedicated outside air system, the difference between system demand and building demand varied from over −40% to almost +30% for cooling and between −20% and +15% for heating. If a heat recovery unit is used, the difference in heating performance is even greater, rising to −70%.     

日照海韵广场超高层综合体空调系统设计

日照海韵广场智慧物贸综合体是集高端办公、五星级酒店为一体的综合建筑.介绍了该项目的 冷热源、风系统、水系统设计,以及需要特别注意的问题.酒店单独设置冷源,采用磁悬浮变频离心机组,热源采用市政热网;办公区冷源采用离心式冷水机组+螺杆式冷水机组,热源采用市政热源;顶层观光层采用多联机空调系统.酒店空调和办公空调水系统采用四...     

Full-scale test and CFD-simulation of radiant panel integrated with exposed chilled beam in heating mode

Thermal conditions in an office room with a chilled beam having integrated radiant panel (CBRP) were analysed in the full-scale laboratory test and using computational fluid dynamic (CFD) simulation. Thermal conditions in the office room were measured in six heating cases under steady state conditions that had different window surface temperatures and internal heat gain conditions. CFD simulations of two measured cases were done in order to investigate indoor climate conditions in more detail and comparing CFD results to measured results. An additional CFD simulation was done with office desk location to near to window to study thermal conditions below the desk. Ventilation efficiency was studied with CFD-simulation. Indoor climate conditions with all measured cases were at good level. Radiant asymmetry and vertical temperature stratification fulfil the requirements of category A in ISO-7730. The highest room air velocities and draught rate readings were 0.16 m/s and 17% respectively. The results indicate that radiant panel heating is applicable solution also in cold climate. Good thermal conditions could be ensured when the temperature of window surface is at least 14–15 °C. At the same time, vertical temperature stratification is acceptable and thus maintains high energy efficiency. Results indicate also that when room is occupied and ventilation is introduced, the temperature gradient is much smaller compared to unoccupied room space.     

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。     

下送上回通风方式供冷与供暖运行性能比较

下送上回通风方式目前得到了广泛的研究应用,其供冷运行时就是置换通风,但同样一套通风系统在一些地区的寒冷季节则有可能需要作供暖运行.为了获得下送上回通风系统在分别作供冷与供暖运行时的具体性能参数,本文应用实验测试与计算流体力学(CFD)模拟的方法研究了置于环境实验室内的某办公环境.研究中分析比较了该办公环境内的空气速度、温度以及追踪气体污染物的浓度分布.研究结果表明,下送上回通风方式作供冷运行时空气温度及污染物浓度分层现象明显,空气处于半混合状态,置换效果较好;作供暖运行时,温度及污染物浓度趋于均匀,通风系统性能接近于混合送风系统,不具备良好的抑制交叉污染的能力.     

北京金融街B7大厦暖通空调设计

介绍了冷热源、供暖、空调、通风及防排烟、控制等系统的设计。办公区采用四管制、变风量系统加散热器供暖系统,且内外区共用同一机组;四季花厅和大堂等大空间采用低温地板辐射供暖系统;大部分百叶风口设在室外绿地地面上,在进排风竖井里进行了消声、过滤、防水、排水处理;新风不作冷热湿处理,直接送入空调机组;空调系统变频节能运行。     

Analysis of annual heating and cooling energy requirements for office buildings in different climates in Turkey

A great amount of world energy demand is connected to the built environment. Electricity use in the commercial buildings, accounts for about one-third of the total energy consumption in Turkey and fully air-conditioned office buildings are important commercial electricity end-users since the mid-1990s. In the presented paper, the interactions between different conditions, control strategies and heating/cooling loads in office buildings in the four major climatic zones in Turkey – hot summer and cold winter, mild, hot summer and warm winter, hot and humid summer and warm winter – through building energy simulation program has been evaluated. The simulation results are compared with the values obtained from site measurements done in an office building located in Istanbul. The site-recorded data and simulation results are compared and analyzed. This verified model was used as a means to examine some energy conservation opportunities on annual cooling, heating and total building load at four major cities which were selected as a representative of the four climatic regions in Turkey. The effect of the parameters like the climatic conditions (location), insulation and thermal mass, aspect ratio, color of external surfaces, shading, window systems including window area and glazing system, ventilation rates and different outdoor air control strategies on annual building energy requirements is examined and the results are presented for each city.     

空调分区系统中几种空调方式的探讨

本文首先指出在办公建筑中,合理的进行内外分区是实现温度均匀分布的关键。说明了在空调分区系统中,采用适当的空调方式给内、外区供冷供热,是减小能耗、节约能源的重要措施。其次介绍了三种在空调分区系统中可以采用的节能的空调方式,分别为:利用冷却塔给内区供冷、以乙二醇为载冷剂给内区供冷及采用变风量调节。并根据工程实例详细讲述了这三种空调方式的使用的环境、工作原理及优缺点。指出这三种空调方式都可以充分利用天然能源,减小能耗。     

Alternative ventilation strategies in U.S.offices:Comprehensive assessment and sensitivity analysis of energy saving potential

Mature technologies exist to reduce the heating,ventilation,and air-conditioning(HVAC) energy associated with ventilation and use ventilation proactively to save energy.This study investigated the energy use impacts in U.S.office buildings of multiple alternative ventilation strategies that combined:economizing,demand controlled ventilation(DCV),supply air temperature reset(SR),and/or a doubled ventilation rate.We used energy simulations in a Monte Carlo analysis,sampling 17 building inputs and varying locations to match the climate zone distribution of the U.S.office stock.Results indicated the possibility for significant savings compared to a baseline that ventilated constantly at a minimum rate in both a small office type with a constant air volume(CAV) HVAC system and a medium office type with a variable air volume(VAV) system.In 95%of instances,HVAC source energy savings were 5-25%in the small-CAV office(median:11%) and 6-42%in the medium-VAV office(median:27%).In the small-CAV office,DCV typically saved the most energy,usually from heating,and heating degree days and occupant density were decisive influences.In the medium-VAV office,economizing and SR were most important,DCV usually only had minor impacts,and zone temperature setpoints,along with climate indicators,were the critical influences.Other than infiltration,envelope characteristics did not strongly influence energy impacts.The untapped primary energy savings of alternative ventilation strategies over the 74%of U.S.office floorspace reasonably represented by our modeling was estimated at 36 TWh per year,with an annual value of U.S.$ 1.25 billion.     

把握时机建造高质量低能耗建筑

作者分析了中国建筑节能的形势,就存在问题提出合理的建议和观点,介绍了节能技术理论和方法,包括节能建筑的概念,适合气候条件的手段及关键。     

北京天元港国际中心空调设计

介绍了北京天元港国际中心的工程概况和空调系统设计,其中包括冷热源系统、水系统、风系统及气流组织、防排烟系统和DDC自动控制系统。总结了目前写字楼设计中需要注意的一些常见问题,如出售型小办公单元的冷热源选择,新风标准较高房间的节能运行,通高大堂的冬季供热问题。     

间歇供暖负荷计算方法研究

以夏热冬冷地区、寒冷地区和严寒地区典型城市的居住建筑和办公建筑为研究对象,分别采用DeST和DesignBuilder软件模拟分析了围护结构、换气次数及散热器和地板辐射两种供暖方式对间歇供暖热负荷的影响,给出了间歇供暖相对于连续供暖的供暖热负荷附加率,确定了合理的间歇供暖模式。结果显示,窗墙面积比对间歇供暖热负荷的影响可以忽略;换气次数每增加0.5h-1,间歇供暖热负荷附加率约增加5%;采用地板辐射供暖的间歇热负荷附加率比散热器供暖小3%～10%。     

Field study of human thermal comfort and thermal adaptability during the summer and winter in Beijing

This study was conducted during the summer and winter in Beijing. Classrooms and offices in a university were used to conduct the survey. The respondents’ thermal sensation and thermal adaptability in both seasons were analyzed. During the study, indoor environmental parameters including air temperature, mean radiant temperature, relative humidity, and air velocity were measured. The respondents’ thermal sensation was determined by questionnaire.A relationship between indoor temperature and thermal sensation was found. In the summer study, the “scissors difference” between TSV and PMV was observed in the air-conditioned environments if the temperature was out of the neutral zone. People had higher tolerance in the hot environment than PMV predicted. During winter, the outdoor temperature had a prominent influence on thermal adaptability. The low outdoor temperature made people adapt to the cold environment. When the indoor temperature was heated to a high temperature by space heating facilities, respondents felt uncomfortable since their adaptability to the cold environment was nullified.Furthermore, the differences in thermal responses between respondents from North and South China showed that the different climates of people's native regions also affected their thermal comfort and adaptability.     

兰州地区办公建筑采暖空调能耗模拟分析

针对兰州地区气候特点,采用建筑热环境模拟软件DeST—c建模分析了兰州地区某办公建筑在两种围护结构情况下的全年采暖空调运行能耗状况,得出两种情况下采暖空调系统全年负荷分布曲线及具体影响,并指出了冷热源装机容量的选择问题。为该地区建筑能耗指标的验证提供了新思路。     

Energy simulation in the variable refrigerant flow air-conditioning system under cooling conditions

As a high-efficiency air-conditioning scheme, the variable refrigerant flow (VRF) air-conditioning system is finding its way in office buildings. However, there is no well-known energy simulation software available so far which can be used for the energy analysis of VRF. Based on the generic dynamic building energy simulation environment, EnergyPlus, a new VRF module is developed and the energy usage of the VRF system is investigated. This paper compares the energy consumption of the VRF system with that of two conventional air-conditioning systems, namely, variable air volume (VAV) system as well as fan-coil plus fresh air (FPFA) system. A generic office building is used to accommodate the different types of heating, ventilating, and air-conditioning (HVAC) systems. The work focuses on the energy consumption of the VRF system in the office buildings and helps the designer's evaluation and decision-making on the HVAC systems in the early stages of building design. Simulation results show that the energy-saving potentials of the VRF system are expected to achieve 22.2% and 11.7%, compared with the VAV system and the FPFA system, respectively. Energy-usage breakdown for the end-users in various systems is also presented.     

A simulation appraisal of performance of different HVAC systems in an office building

The article reports on a simulation appraisal of energy consumption, energy costs and environment impact of three systems used for space heating, and space cooling of an office building in Kragujevac, Serbia. Three investigated systems are (1) a system with a natural gas boiler and convective baseboard heaters for water space heating and window air conditioners for air space cooling; (2) a system with a natural gas boiler and individual air reheaters for air space heating and a chiller plant for air space cooling; and (3) an air-to-air heat pump for air space heating, and cooling. The systems are modeled and simulated by using EnergyPlus software. After simulations, it is found that the first investigated system has the highest energy efficiency, the best economy, and the lowest environmental impact. That is because of the fact that the first system has water as a heating medium and uses predominantly natural gas as fuel. However, in future, when for generation the grid electrical energy requires less primary energy, and becomes decarbonized, the third system would be best to conserve energy resources and environment.     

Determination of particle concentration in the breathing zone for four different types of office ventilation systems

Many factors affect the airflow patterns, thermal comfort, contaminant removal efficiency and indoor air quality at individual workstations in office buildings. In this study, four ventilation systems were used in a test chamber designed to represent an area of a typical office building floor and reproduce the real characteristics of a modern office space. Measurements of particle concentration and thermal parameters (temperature and velocity) were carried out for each of the following types of ventilation systems: (a) conventional air distribution system with ceiling supply and return; (b) conventional air distribution system with ceiling supply and return near the floor; (c) underfloor air distribution system; and (d) split system. The measurements aimed to analyse the particle removal efficiency in the breathing zone and the impact of particle concentration on an individual at the workstation. The efficiency of the ventilation system was analysed by measuring particle size and concentration, ventilation effectiveness and the indoor/outdoor ratio. Each ventilation system showed different airflow patterns and the efficiency of each ventilation system in the removal of the particles in the breathing zone showed no correlation with particle size and the various methods of analyses used.     

Improved HVAC operation to preserve a church organ

The common operation of heating systems installed in churches in the Netherlands has led to typical building physics problems directly related with heating. One of the main problems is the drying related shrinkage and damage to (monumental) wooden organs under cold winter conditions. The paper presents an integrated heat, air and moisture model including modelling components for: the indoor climate of the church, the heating systems and operation, and the moisture distribution in wood. The modelling components are validated with measurements. Two types of control strategies are discussed. The first type is a limited indoor air temperature changing rate. The second type is a limited indoor air relative humidity changing rate. This preliminary study shows that a limitation of indoor air temperature changing rate of 2 K/h can reduce the peak drying rates by a factor of 20 and a limitation of the relative humidity changing rate of 2% per hour can reduce the peak drying rates by a factor of 50. The second strategy has the disadvantage that the heating time is not constant and therefore more difficult to implement in relation with early start-up.