毛细管重力循环供冷末端设备性能研究

发布时间：2018-01-18 07:16

本文关键词：毛细管重力循环供冷末端设备性能研究　出处：《天津商业大学》2013年硕士论文　论文类型：学位论文

【摘要】：降低以供冷为主的建筑能耗，利用地表水和可再生能源等高温能源供冷，实现能源的阶梯利用是目前建筑能源领域的研究课题之一。风机盘管联合新风、全空气等空调系统形式在现代建筑中被广泛采用，通过空气对流的形式进行热量交换，室内温度分布容易出现不均匀性，而且会造成能源的巨大浪费。辐射空调供冷方式作为一种新型、节能的空调方式，以毛细管为换热元件，利用16~18℃冷水进行供冷，能够有效利用低品位能源。当房间维护结构的保温措施做得比较好时，对于人员活动量比较小的房间，辐射空调方式有可能能够满足负荷要求，不需要额外的补助制冷方式。但是，在大部分情况下，供冷过程中辐射板的供冷能力受结露风险以及室内吊顶空间的限制，辐射吊顶不能完全消除室内显热负荷。当房间由于某种需要人员突然增多时，室内的负荷会相应跟着突然增大，由于辐射空调系统的降温速度较慢，也需要补助制冷方式进行加速降温处理。在增加辐射空调末端制冷量的措施中，大都围绕改变辐射板本身的结构的研究，在板表面进行一些技术处理，通过防结露的措施达到增加制冷量的目的。然而，此举虽有效的提高了辐射板的供冷能力，但是仍不能达到单依靠辐射板消除全部室内负荷的效果。重力柜是将毛细管网置于特殊制作的柜壳中，柜壳外表面上下开风口，依靠循环柜内空气与室内空气的密度差，室内与循环柜之间形成仅依靠热压作用的空气自然对流循环，达到降低室温的目的。本文在设备结构参数的优化研究中，通过Fluent数值模拟的方法得到设备的温度场分布特性，分析了设备内置毛细管网的管间距、管排数以及安装位置等参数对温度场、冷量的影响，以及室内流场分布情况。在设备的运行特性研究中，实验方法研究重力柜的供冷能力以及重力柜壁面盘管的冷量贡献率，使用吊顶辐射供冷系统时，在某些地区，当吊顶辐射不能完全消除室内负荷，或者当房间负荷突然增加，室内温度不能快速有效得到控制时，重力柜作为补助制冷设备起到补充冷量的作用，实验方法研究重力柜的补助制冷性能以及对室内热舒适性的影响。研究结果表明：重力柜内置毛细管网管间距为20mm、管排数由1排增加到2、3排时，冷量由218.4W增加到430.1W、737.6W，能够显著提高重力柜的供冷性能；当内置1排毛细管网、管间距由30mm、减小到20mm、10mm时，冷量由197.4W增加到249.7W；重力柜厚度为150mm、内置1排毛细管网、管间距为20mm时，与后壁面、风口面距离分别为60、85.7mm时，冷量值达到最大218.4W。当重力柜内置3排毛细管、入口速度为0.15m/s时，出风口冷空气的影响范围达到重力柜风口前方1.9m处；由于出风口周围地面的温度比较低，出风口周围的地板结构具有蓄冷作用，使得地面以辐射、对流形式消除部分室内负荷，一定时间内也能维持供冷效果。由此可知，重力柜具有部分辐射供冷的效果。重力柜联合吊顶辐射板运行时，在室内达到稳定状态后，，距重力柜水平0.3m以内的区域，最大垂直温差达到3.5℃；0.3m以外的区域，人体活动区温度梯度在0.9-2.6℃内，符合ASHRAE手册中人体热舒适性标准的要求。因此建议采用重力循环系统形式时，将人员活动区设在距离重力柜水平0.8m以外的区域，由PMV和PPD值分析得知，重力柜对室内热舒适性没有影响。
[Abstract]:In order to reduce the cooling of the building energy consumption, the use of surface water and renewable energy such as high temperature and cooling energy, realize the energy ladder use is one of the research topics at present in the field of building energy. The fan coil combined with fresh air, the air conditioning system in the form of modern architecture is widely adopted by air convection in the form of heat exchange, indoor temperature distribution is not prone to uniformity, and will cause a huge waste of energy. The radiation cooling mode as a new type of air conditioning, energy saving, with capillary tube as heat transfer components, cooling by 16~18 C cold water, can effectively use the low grade energy.
When the room maintenance structure heat preservation measures are doing better, for a relatively small amount of personnel activity room, radiation air conditioning system has the potential to meet the load requirements, do not need to grant additional cooling. However, in most cases, the risk of condensation and cooling capacity by indoor ceiling space limit radiation panel cooling in the process of radiant ceiling can not completely eliminate indoor sensible heat load. When the room due to a sudden increase in the need for personnel, the indoor load will follow a sudden increase due to radiation air conditioning system cooling speed is slow, also need to grant cooling accelerated cooling treatment.
The increase in end radiation air conditioning refrigeration volume measures, mostly centered on the change of structure of the radiation plate itself, some technical process on the surface of the plate, through the condensation prevention measures to increase the cooling capacity. However, although this can effectively improve the cooling capacity of the radiation plate, but still can not achieve the single rely on radiation in eliminating all indoor load effect.
The gravity cabinet is to place capillary net in the special cabinet, and the outer surface of the cabinet is opened up and down, and the air density of the air in the circulation cabinet is different from that of the indoor air. Indoor air circulation is formed between the indoor cabinet and the circulation cabinet, and the natural convection circulation is only achieved by hot pressing, so as to achieve the purpose of reducing the room temperature.
Study on Optimization of structural parameters of the equipment in this paper, the temperature field distribution equipment is obtained through Fluent simulation, analysis of the tube spacing device with built-in capillary network, the number of tube rows and the installation position and other parameters on the temperature field, the effects of cold quantity, and indoor air flow distribution.
The operation characteristics of the equipment, the cooling capacity with cooling capacity of experimental methods to study the gravity tank and gravity tank wall coil, use ceiling radiant cooling system, in some areas, when the ceiling radiation cannot completely eliminate indoor load, or when a sudden increase in room load, the indoor temperature can not be controlled effectively when the gravity tank as subsidies to refrigeration equipment cooling capacity, cooling performance allowance experiment method to study the gravity tank and the influence of indoor thermal comfort.
The results show that: gravity capillary network cabinet built-in distance is 20mm, the tube row number of rows increases from 1 to 2,3, the cooling capacity increased from 218.4W to 430.1W, 737.6W, can significantly improve the cooling performance of the gravity tank; when the built-in 1 rows of capillary network, tube spacing by 30mm, reduced to 20mm, 10mm. The cooling capacity increased from 197.4W to 249.7W; gravity tank thickness is 150mm, built in 1 rows of capillary network, tube spacing is 20mm, and after the wall outlet surface distance is 60,85.7mm, the cooling capacity reaches the maximum value of 218.4W.
When the gravity tank built in 3 rows of capillary entrance velocity is 0.15m/s, the influence of cold air to air outlet at the gravity tank in front of 1.9m; for the air outlet of the surrounding ground temperature is relatively low, the floor structure around the air inlet with cold storage function, which makes the ground to radiation, convection eliminate indoor load, a certain period of time also can maintain the cooling effect. Therefore, the gravity part cabinet has radiation cooling effect.
Gravity tank combined with radiation board operation, to reach a steady state in the room, from within the gravity tank level of 0.3m area, the maximum vertical temperature difference reaches 3.5 DEG 0.3m; the area outside the area of human activities, the temperature gradient at 0.9-2.6 DEG C, in line with the ASHRAE Manual of human thermal comfort standards. It is proposed to use the gravity circulation the form of system, the personnel activity area is located in the distance from the gravity tank level 0.8m area by PMV and PPD value analysis shows that the gravity tank on indoor thermal comfort has no effect.

【学位授予单位】：天津商业大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU831.4

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