辐射供冷-贴附射流复合空调系统负荷分配比例研究

以济南某应用辐射供冷-贴附射流复合空调系统的会议室为模型,利用有限元数值模拟方法,对不同负荷分配比例下室内的热湿环境进行数值模拟。新风除湿过程中,伴随着空气湿度的降低,空气的温度必然也会受到影响,因此,存在一个新风除湿时所承担的最小显热负荷比例。对于本文研究的模型,经计算该比例为8.9%左右,以新风承担负荷比例10%为起点,将研究工况分为9种。研究结果表明,考虑室内热舒适性、空气品质和能耗等因素,辐射板承担的冷负荷比例控制在60%左右为宜。     

天棚辐射采暖制冷系统在当代万国城Pop Moma楼盘中的应用

一、国外辐射采暖制冷技术的发展1989年,欧洲第一座结合应用“置换式新风系统+外置式辐射采暖制冷系统”的办公建筑MesserliLtd.在Wetzikon落成并投入使用。该建筑采暖能耗每年60MJ/m2,制冷能耗每年40MJ/m2。后来由于外置式辐射采暖制冷系统不太美观,布鲁诺·凯乐教授于1989年开始设计“置换式新风系统+内置式混凝土楼板天棚辐射采暖制冷系统”的办公建筑Sarinaport,Fribourg。该建筑于1991年顺利落成并投入运行。于是,一个温湿度适宜、无风感、无噪声、健康舒适的节能建筑诞生了。二、天棚辐射采暖制冷系统近年来,我国的地板辐射采暖系…     

办公建筑中吊顶辐射空调系统夏季工况性能测试研究

以办公建筑中实际使用的一套金属吊顶辐射板+新风的空调系统为研究对象,对夏季运行工况进行了测试研究。分别对比分析了高温和高湿气象条件下办公建筑室内的温湿度分布,比较了不同高度和不同位置处的温湿度场,在测试条件下,室内有良好的热舒适性。     

置换通风辐射空调不同结合方式的模拟比较

置换通风和辐射空调这两种空调方式的结合是目前运用较少的空调末端方式,置换通风主要是解决空调房间新风供给和承担房间的湿负荷.模拟研究设计条件下置换通风天棚辐射供冷与置换通风地板辐射供冷时房间的温度、湿度和速度分布,从而优化设计、避免结露.模拟结果表明在同样的设计条件下,置换通风天棚辐射供冷具有较好的的温度分布、湿度分布和速度分布.     

温湿度独立控制空调系统在医院项目中的应用

医疗建筑室内空气质量要求较高且能源消耗量很大，是单位面积能耗最大的公共建筑之一。新冠肺炎疫情暴发以来，医疗建筑集中式空调系统的安全性、可靠性更加受到社会各界的关注。温湿度独立控制空调系统基于空调末端干工况运行、新风承担全部湿负荷，配合高效能冷热源可大幅提高室内空气质量、降低运行能耗。本文所介绍的医院项目采用了蓄能型楼板双面辐射供冷供暖+双冷源新风机组深度除湿置换通风+地埋管式地源热泵冷热源的温湿度独立控制空调系统。实测运行数据表明：2020年该空调系统单位空调面积(扣除车库、设备用房等)运行费用为39元/m²,折合单位建筑面积年运行费用为31元/m²;室内空气质量良好。     

某银行大楼双冷源(集中式)温湿度独立控制空调系统设计

介绍了某银行大楼的空调冷热源及末端机组设计。根据建筑使用功能和室内热舒适性要求，分析了室内热湿负荷分布与构成，结合双冷源(集中式)温湿度分控技术，实现了高温冷源承担新风预冷负荷及室内显热负荷，低温冷源承担新风除湿负荷及室内潜热负荷的冷热源方案。探索了双冷源(集中式)新风机组+干式风机盘管+主动式冷梁末端的应用。从空调系统的选择、温湿分控运行策略、技术经济比较等方面分析了该系统的适用性、节能性与经济性。     

直接蒸发式低温辐射板加独立新风空调系统设计应用

本文以某单位会议室为例,对采用直接蒸发式低温辐射板+独立新风空调系统的设计应用进行研究,直接蒸发式低温辐射板负担室内冷负荷和部分湿负荷,新风系统负担新风负荷,该系统采用了全热交换、辐射供冷(暖)及独立新风等节能技术,不但提高了舒适性,而且节约了运行能耗。     

辐射供冷供热与风机盘管加新风系统在工程中的联合应用北大核心

介绍了乌鲁木齐高铁新区综合医院建筑物概况、当地气候特点及空调系统形式,分别介绍了冬季和夏季工况空调冷水机组系统及末端风机盘管系统、新风系统、地板辐射供冷供暖系统的选择情况及各项设计冷负荷、热负荷的分配情况。     

辐射供冷供热与风机盘管加新风系统在工程中的联合应用

介绍了乌鲁木齐高铁新区综合医院建筑物概况、当地气候特点及空调系统形式,分别介绍了冬季和夏季工况空调冷水机组系统及末端风机盘管系统、新风系统、地板辐射供冷供暖系统的选择情况及各项设计冷负荷、热负荷的分配情况。     

夏热冬冷地区办公楼温湿度独立系统室内热环境研究

本文利用Airpark软件对夏热冬冷地区典型办公楼层进行建模,分别模拟干盘管加全热回收新风系统、冷辐射吊顶加置换新风系统,通过不同的室内流场、温度场、速度场、PMV模拟结果,得出:夏热冬冷地区采用温湿度独立控制系统,工作区域温度基本可维持在24℃-26℃,PMV值均可以满足I级热舒适等级;冷辐射吊顶加置换通风方式,室内风速较低,温度场更均匀,优先应用在热舒适度要求较高的区域.     

Thermal comfort and energy consumption of the radiant ceiling panel system.: Comparison with the conventional all-air system

The purpose of this study is to investigate the various characteristics of a radiant ceiling panel system and their practical application to office buildings. The radiant ceiling panel system and conventional air-conditioning system were compared in terms of thermal comfort, energy consumption, and cost. Thermal environment, along with human response, was tested by using a small meeting room equipped with radiant ceiling panels. The responses were collected by questionnaires given to the male subjects in the room. The experiment for the female subjects was conducted separately. Results show that the radiant ceiling panel system is capable of creating smaller vertical variation of air temperature and a more comfortable environment than conventional systems. When using a cooled ceiling, a small volume of supplied air creates a less draught environment, which reduced the discomfort of feeling cold in the lower part of the body. Numerical simulation of yearly energy consumption and cost estimation were conducted. Typical office rooms located on the 3rd, 4th, and 5th floor of a six-floor building in the Tokyo area were simulated. Since part of the sensible heat load is handled by radiant ceiling panels, the volume of supplied air can be reduced, leading to lower energy consumption for air transport. By using the radiant ceiling panel system in one of the three floors of the simulated building, energy consumption can be reduced by 10%. Estimated pay back time was from 1 to 17 years depending on the market price of the radiant ceiling panel.     

Solar radiation and cooling load calculation for radiant systems: Definition and evaluation of the Direct Solar Load

The study of the influence of solar radiation on the built environment is a basic issue in building physics and currently it is extremely important because glazed envelopes are widely used in contemporary architecture.In the present study, the removal of solar heat gains by radiant cooling systems is investigated. Particular attention is given to the portion of solar radiation converted to cooling load, without taking part in thermal absorption phenomena due to the thermal mass of the room. This specific component of the cooling load is defined as the Direct Solar Load.A simplified procedure to correctly calculate the magnitude of the Direct Solar Load in cooling load calculations is proposed and it is implemented with the Heat Balance method and the Radiant Time Series method.The F ratio of the solar heat gains directly converted to cooling load, in the case of a low thermal mass radiant ceiling, is calculated for different kinds of office rooms with a large glazed external surface. An example of cooling load calculation developed with the proposed procedure is given.     

Numerical analysis of diffuse ceiling ventilation and its integration with a radiant ceiling system

A novel system combining diffuse ceiling ventilation and radiant ceiling was proposed recently, with the aim of providing energy efficient and comfort environment to office buildings. Designing of such a system is challenging because of complex interactions between the two subsystems and a large number of design parameters encountered in practice. This study aimed to develop a numerical model that can reliably predict the airflow and thermal performance of the integrated system during the design stage. The model was validated by experiments under different operating conditions. The validated model was further applied to evaluate the effects of different design parameters, including the U-value of the diffuse ceiling panel, plenum height, plenum depth, and inlet configuration. In the integrated system, diffuse ceiling separated the radiant ceiling from the rest of the room and consequently changed the energy efficiency of the radiant system. The simulated results demonstrated that using ceiling panel with a higher U-value can minimize this impact and make the system to cool down space efficiently. Low plenum height was beneficial to the energy efficiency, but aggravated the non-uniformity air distribution and further led to the draught problem in the occupied zone. This system was recommended to apply in the small offices instead of large, open spaces.     

Experimental evaluation of heat transfer coefficients between radiant ceiling and room

The heat transfer coefficients between radiant surfaces and room are influenced by several parameters: surfaces temperature distributions, internal gains, air movements.The aim of this paper is to evaluate the heat transfer coefficients between radiant ceiling and room in typical conditions of occupancy of an office or residential building. Internal gains were therefore simulated using heated cylinders and heat losses using cooled surfaces. Evaluations were developed by means of experimental tests in an environmental chamber.Heat transfer coefficient may be expressed separately for radiation and convection or as one total parameter, but this choice may lead to different considerations about thermal performance of the system. In order to perform correct evaluations, it is therefore extremely important to use the proper reference temperature.The obtained values confirm tendencies found in the literature, indicating limitations and possibilities of radiant ceiling systems improvement.     

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%。     

一种适用于长江流域冬季的新型空调方式--辐射板+自然通风

在我国长江流域,冬季具有室外气温高,空气相对湿度极大的特点。在这种空调负荷较小的情况下,笔者认为完全可以采用一种新型的空调方式-“辐射 自然通风”,辐射方式的采用,降低了室内的空气温度,这样,使用自然通风也不会增加很多负荷,而自然通风的采用,会大大改善室内的空气品质。笔者从热负荷,舒适度,通风量,气流组织四个方面简单地论证了其可行性,并举例说明一个具体的系统方式及系统计算,分析了这种方式的优缺点及具体的适用范围,指出它对于城市建筑物中占很大比例的两类建筑-普通住宅及办公建筑是适用的。     

Displacement ventilation environments with chilled ceilings: thermal comfort design within the context of the BS EN ISO7730 versus adaptive debate

The current design standard BS EN ISO7730 [Moderate thermal environments—determination of the PMV and PPD indices and specification of the conditions for thermal comfort, International Standards Organisation (1995)] is based upon the work of Fanger, and essentially comprises a steady-state human heat balance model that leads to a prediction of the sensation of human thermal comfort for a given set of thermal conditions. The model was derived from laboratory-based measurements conducted in the mid-1960s in relatively ‘conventional’ environments. However, a chilled ceiling operated in combination with displacement ventilation represents a more sophisticated environment as compared with the original conditions in which the Fanger model was derived. This raised a question about the applicability of the current standard when designing for thermal comfort in offices equipped with chilled ceiling/displacement ventilation systems. This paper presents findings from an EPSRC-funded study that sought to answer the above question. Human test subjects (184 in total) carried out sedentary office-type work in a well-controlled environmental test room that simulated an office fitted with the above system. Measurements of environmental variables were taken at a number of locations near the subjects, each of whom wore a typical office clothing ensemble. The reported thermal comfort sensations were compared with values predicted from BS EN ISO7730 over a range of system operating conditions. It was shown that the current standard BS EN ISO7730 may be used, without modification, when designing for the thermal comfort of sedentary workers in offices equipped with chilled ceiling/displacement ventilation systems. These findings are interpreted within the context of a proposed modification to thermal comfort design standards that includes adaptive effects, and the influence of BS EN ISO7730 on the development of other radiant surface/displacement ventilation configurations is discussed.     

冷却顶板空调系统中热环境分析

采用CFD软件,探讨了某通透大型玻璃幕墙建筑顶板冷辐射空调系统中的空调方案对室内热环境的影响,并进行了热舒适评价,研究表明：在不能安装辐射换热管系统的部分空间内,可以采用安装地板辐射管,并采取适当的通风方式带走室内余热以达到设计要求。     

Experimental and numerical analysis of air and radiant cooling systems in offices

This paper analyses office cooling systems based on all air mixing ventilation systems alone or coupled with radiant ceiling panels. This last solution may be effectively applied to retrofit all air systems that are no longer able to maintain a suitable thermal comfort in the indoor environment, for example in offices with high thermal loads.