下送风空调技术综述

随着越来越多现代化、智能化的办公大楼的建设,新型办公楼室内布局的不断变化,以及人们对舒适性尤其是室内空气品质要求的提高,下送风空调方式逐渐被采用。本文介绍了下送风空调技术目前的研究现状,并从这种空调方式的原理出发,综述了下送风技术在热环境、舒适性、空气品质、节能等方面的特点,比较了该系统与传统上送风空调系统之间的差异。最后指出了目前该空调技术在实际应用中的若干问题。     

地铁车厢送风参数对气流组织影响的研究现状

介绍了地铁车厢空调系统送风参数的选取原则和依据,综述了前人对地铁车厢空调系统送风参数的实测结果和气流组织的数值模拟结果,总结了送风参数对地铁车厢内气流组织的影响规律。结果表明,辐流风机有助于改善车厢内气流组织的均匀性;B型地铁载人情况下,当送风速度在1.5m/s左右时,车厢内速度场的均匀性较好;对于相同微风速环境下的A型地铁来说,满载车厢的空调送风速度高于空载车厢的送风速度,以上研究结果为提高地铁车厢的舒适性提供了理论基础。     

空调房间气流组织的数值模拟研究

利用Fluent软件,从室内的速度场、温度场及室内CO_2浓度场分布出发,模拟研究了某一空调房间内置换通风和侧送风两种空调方式的差异性。结果表明:置换通风方式在提高人体热舒适性、改善工作区空气品质及节能等方面要优于侧送风方式。     

大空间两种气流组织夏季热环境及其能耗实验研究

以某大空间实验基地为研究对象,针对喷口送风和柱状下送风两种分层空调的热环境及供冷量进行了实测研究.研究结果表明:因喷口送风空调区较大,在夏季室外气象参数基本相同的两种室外气象条件下,喷口送风空调系统供冷量比柱状下送风空调系统的供冷量分别高出20.8%、24.4%,且喷口送风空调系统抗干扰能力较柱状下送风强;喷口送风时工作区温度均匀性好于柱状下送风,头足温差较小,但其工作区风速超过标准,而柱状下送风时工作区风速则符合环境设计要求;两种不同送风量下喷口送风时吹风感指数分别为15.64%、11.23%,而柱状下送风时吹风感指数分别为4.17%、2.40%,柱状下送风要明显优于喷口送风.故从节能及热舒适性角度综合考虑,单侧回风的大空间建筑应尽可能采用柱状下送风分层空调,而对于干扰比较大,空调场地较小,无法布置柱状下送风口的场合,则选取喷口送风较好.     

不同送风方式对热舒适度的影响

为了研究不同送风方式对空调房间内舒适度的影响,用实验方法测得下送风、侧送风和上送风3种方式下空调房间不同位置的热舒适度。实验结果表明,空调房间侧送风方式下的舒适性最好,此结论可为空调房间的设计提供参考。     

高大铁路旅客候车室空调送风方式的选择

结合深圳北站空调系统的设计情况,从节能、舒适性出发,介绍高大空间的旅客候车室其空调送风方式的特点及适宜送风方案:旅客进出站通廊区域采用条形风口侧送风方式;大面积候车区域采用高位球形喷口送风方式;商业岛采用低位置换式孔板送风方式。     

地板下空调送风技术概述

地板下空调送风技术作为一项新的空调系统设计手段,利用架空地板下部空间输送空调气体,已广泛应用于高档办公楼。由于地板下送风空调系统相对于天花吊顶上送风空调系统具有节能、洁净、舒适等优点,所以该技术在北美地区迅速发展。地板下空调送风示意图见图1。自从1995年起,美国     

某地铁项目空调送风道结构优化

在某地铁项目空调送风道方案设计完成的前提下,利用Catia三维软件进行M车空调送风道建模,然后,利用计算流体模拟软件Fluent对空调送风道进行CFD仿真分析,从而可以得出气流在风道、格栅和客室内部的流动状况。通过统计送风格栅各段的送风量,分析风道送风均匀性,从而最终确定最合理的送风道结构形式,以此改善此项目空调送风均匀及温度均匀性,提高客室空调整体舒适性。     

数值模拟优化汽车尾气检测环境仓设计

对空调系统两种送风温度下汽车尾气检测环境仓内的速度场和温度场进行了数值模拟与分析,得出在两种情况下仓内环境均能满足尾气检测要求。并对两种送风参数下空调系统进行节能分析,得出一种节能的设计方案,从而优化环境仓的设计。     

隔断式工位空调系统气流组织与人体热舒适评价

采用K-ε湍流模型对采用隔断式工位空调的典型办公室工作微环境进行数值模拟,分析工位空调在人体周围所形成的非均一环境参数场,并进一步研究非均匀环境对人体热舒适的影响.在不同工位送风参数下对房间和人体周围环境参数的分布状况及吹风感和热舒适性进行研究.模拟结果发现:工位空调送风可以使室内温度呈现分区分布,工位送风效率高,可以...     

某游泳馆空调三维紊流流场的CFD模拟与研究

为评价游泳馆空调方案的气流组织设计,用k-ε模型对某游泳馆空调室内空气三维紊流流场进行了模拟,预测了游泳馆内的速度场、温度场。对模拟结果进行了分析与研究,表明CFD模拟可以为游泳馆空调系统的节能设计提供依据。     

Enthalpy estimation for thermal comfort and energy saving in air conditioning system

The thermal comfort control of a room must consider not only the thermal comfort level but also energy saving. This paper proposes an enthalpy estimation that is conducive for thermal comfort control and energy saving. The least enthalpy estimator (LEE) combines the concept of human thermal comfort with the theory of enthalpy to predict the load for a suitable setting pair in order to maintain more precisely the thermal comfort level and save energy in the air conditioning system.     

Effect of neutral temperature on energy saving of centralized air-conditioning systems in subtropical Hong Kong

Higher room temperature can still let the occupants have a neutral thermal sensation if higher air speed is provided. With a suitable scheme of neutral temperature and comfort air speed, reduction of energy consumption of the central chiller plant may surpass the additional energy requirement of the air side equipment, then both energy saving and thermal comfort can be achieved for the entire air-conditioning system. To evaluate this, the energy consumptions of a centralized air-conditioning system using the common air side alternatives were studied for the subtropical Hong Kong. The alternatives are variable air volume (VAV) system, constant air volume (CAV) system and fan coil (FC) system. Each of them was associated to a central chiller plant to serve a high-rise office building. The studying range of the room air temperature was from 23 °C to 30 °C. It is found that the VAV and FC systems can provide both thermal comfort and energy saving for higher room temperature, but CAV system is not feasible when the room air temperature is above 27 °C. If the indoor air speed threshold is considered, the neutral temperature can be brought up to 26.5 °C, and the energy saving potentials of VAV and FC systems would be 12.9% and 9.3% respectively.     

Development of novel control strategy for multiple circuit, roof top bus air conditioning system in hot humid countries

A novel control strategy to improve energy efficiency and to enhance passengers’ thermal comfort of a new roof top bus multiple circuit air conditioning (AC) system operating on partial load conditions is presented. A novel strategy for automatic control of the AC system was developed based on numerous experimental test runs at various operating conditions, taking into account energy saving and thermal comfort without sacrificing the proper cycling rate of the system compressor. For this task, more than 50 test runs were conducted at different set point temperatures of 21, 22 and 23 °C. Fanger’s method was used to evaluate passenger thermal comfort, and the system energy consumption was also calculated. A performance comparison between that of the conventional AC system and that of the newly developed one has been conducted. The comparison revealed that the adopted control strategy introduces significant improvements in terms of thermal comfort and energy saving on various partial load conditions. Potential energy saving of up to 31.6% could be achieved. This results in a short payback period of 17 months. It was found from the economic analysis that the new system is able to save approximately 20.0% of the life cycle cost.     

浅谈地板辐射供暖技术

地板辐射采暖是一种舒适、环保、节能的现代供暖方式。在诸多供暖技术中,地板辐射供暖技术无疑是热舒适度最好的一种供暖方式。在设计中,不但要对地面构造、热媒、热管系统及分集水器进行合理的设计,还要分别对负荷、散热量和热管水力进行系统的计算,同时加以正确的选材与施工才能充分发挥出地板辐射供暖的技术的优势。     

夏季套室内人体热舒适的数值预测

用数值方法预测了夏季套室内气流的速度、温度、人体热舒适指数干球合成温度等参数的分布，计算中考虑太阳热辐射和外界气温等条件的影响。根据相关成果，对预测出的套室内人体热舒适进行评定，所预测套室内环境达到了人体的热舒适性基本要求，并得到舒适情况下的干球合成温度范围。     

城市住宅小区建筑室内外环境对局部气候的影响

以天津某高层住宅小区为对象,建立了小区建筑和室内户型的计算分析模型。基于CFD方法,开展了在冬、夏季典型气候下的室外风气候特性、室内自然通风情况的模拟分析研究。得到了住宅小区室外风速、风压的分布场、室内三维速度场、温度场分布场。探讨了风向、风速、窗户对局部气候的影响。研究表明对室外风环境,由于小区建筑的分布特征,存在着局部增强的强风区,最大速比达到1.8;就室内气候而言,具有自然对流效果的A型房间的自然通风效果要优于B型房间。通过对既有城市住宅小区的室内外气候环境的模拟分析,可以为建筑气候的设计提供重要的参考价值。     

Energy saving by integrated control of natural ventilation and HVAC systems using model guide for comparison

Integrated control by controlling both natural ventilation and HVAC systems based on human thermal comfort requirement can result in significant energy savings. The concept of this paper differs from conventional methods of energy saving in HVAC systems by integrating the control of both these HVAC systems and the available natural ventilation that is based on the temperature difference between the indoor and the outdoor air. This difference affects the rate of change of indoor air enthalpy or indoor air potential energy storage. However, this is not efficient enough as there are other factors affecting the rate of change of indoor air enthalpy that should be considered to achieve maximum energy saving. One way of improvement can be through the use of model guide for comparison (MGFC) that uses physical-empirical hybrid modelling to predict the rate of change of indoor air potential energy storage considering building fabric and its fixture. Three methods (normal, conventional and proposed) are tested on an identical residential building model using predicted mean vote (PMV) sensor as a criterion test for thermal comfort standard. The results indicate that the proposed method achieved significant energy savings compared with the other methods while still achieving thermal comfort.