外文翻译--温湿度独立控制的空调设备在办公大楼的工作情况.docx

附录5 英文参考资料1 中文翻译温湿度独立控制的空调设备在办公大楼的工作情况传统的供热通风与空气调节系统通过冷凝的方式除湿，在给空气除湿的同时，也把空气冷却了。在大多数情况下，建筑物的显性负载占了制冷负载的大部分，而隐性负载（除湿负载）只占很小一部分。但是，由于除湿需要的冷源温度比降温所需的冷源温度要低得多，因此冷却水的温度必须降得足够低，以满足冷凝除湿的要求。此外，显性负载和隐性负载之比很大程度上随室外天气、室内人员的数量、室内设备和照明方式的变化而变化。所以，室内温度和室内湿度这两个参数，很难通过冷却旋管冷凝这一种方式进行有效的调节。实践中，在室内湿度升高时，为了除湿，就调低设定的温度值。当空气通过了冷凝旋管后，再将空气加热到合适的温度，这样就造成了很大的能源浪费。为了避免上述的问题，温度、湿度独立控制空调系统以其合适的工作方式独树一帜，它可以让温度和湿度分别通过温度控制子系统和湿度控制子系统独立地进行控制。另外，温度控制子系统中用来降温的旋管的温度可以大幅提高，也就是说，可以从当前的7提高到17，于是就可以提升制冷机的工作状况，甚至可以实现不受周围环境影响的自由调温。在混合式干燥剂除湿与空调系统上，已经有很多人进行过研究，他们通过把液态、固态干燥剂和传统的冷却系统进行整合，达到避免过度冷却的目的。液态干燥剂在最近几年有了长足的发展，因为它有一个很显著的优点，可以在高于露点温度的情况下除湿，避免了冷却后重新对空气加热的过程。有许多人，包括Yadav, DryKor Ltd. 和Liu et al. Chen et al.等，已经对如何提升它的效果进行了深入的研究。他们设计了一个独立的除湿空调系统，它用热水驱动液态干燥剂，并且把18-21的冷却水供给北京的一个办公大楼。与传统的空调系统相比，这个系统节省了30%的制冷费用。由Ma et al测试的混合系统的工作效果比传统水蒸气压缩系统好44.5%，隐形负载为30%，并且这两个优势分别可以提高到73.8%和42%。此外，关于混合系统在天气很热且潮湿的地区的可行性和工作情况的专门研究也得到了大力支持。本文将对深圳的一个办公大楼里面的THIC空调系统的真实工作情况进行调查研究。在这个THIC系统里，由热泵驱动的液态干燥剂新鲜空气处理单元被用来处理室外的空气，去除所有的隐性负载并给整个空间提供足够的新鲜空气。那个为室内终端设备提供17.5摄氏度的冷却水的高温冷却装置被用来控制室内温度。THIC系统的工作原则和工作情况测试结果都将在本文中得到展示，我们还将对改善系统的工作表现提出建议。深圳的这个空调系统的基本信息如下。这个五层的办公大楼坐落于中国深圳，总共建筑面积为21960平方米，从一楼到五楼分别为5940平方米、5045平方米、3876平方米和3908平方米。深圳户外的天气全年都很热且潮湿，年室外空气相对湿度大约为80%，夏天的适度比高达20g/公斤干空气。整栋建筑在相当长的时间内需要制冷和除湿，但是在冬季却不需要制热和加湿。所以，如何处理湿气就成了这个亚热带城市的关键问题。THIC系统的工作范围包括一至四楼，净面积13180平方米，而第五楼由若干个独立的空调来调节温度，因此它不在我们讨论的范围内。图4右边是湿度控制子系统，包括9个为整个空间提供足够干燥空气的的液态干燥剂新鲜空气处理单元。由于能提供的新鲜空气的容量与建筑内的人的数量是成比例的，所以污染物、二氧化碳和人释放的隐形热量都能通过这些新鲜空气排出。图5描述了由液态干燥剂构成的新鲜空气处理器的原理图，它包括一个两步总热量恢复装置和一个与冷藏周期耦合的两步空气处理装置。LiBr被用作这些空气处理器里的液态干燥剂。总热量恢复装置用来恢复由于室内废气造成的能量损失，以便减少新鲜空气处理过程中的能量消耗。在由热泵驱动的空气处理装置中，除湿模块里面的稀释溶液被冷凝器的废热加热，在重造模块中集中，然后这个浓缩的热溶液通过热交换器和蒸发器，于是温度降低，然后再进入除湿模块，最后，它被用来去除新鲜空气中的湿气。总体上看，液态干燥剂新鲜空气模块要除掉空气中的热量，需要在热泵和溶液泵上花费5倍的能量，这主要归结于以下原因：（1）通过总热量恢复装置，充分利用了室内废气的冷却功能，以去除新鲜空气中的热量。（2）蒸发器的冷却容量和冷凝器的废热气都被用来改善空气处理过程（3）由于在这个液态干燥剂装置中的蒸发温度比传统冷凝除湿系统的要高很多，所以热泵的效率得到了很大的提升。此外，正如图5中所展示的，供应的空气的温度比室内空气温度低，所以液态干燥剂系统不仅可以去除一些显性负载，还可以去除整个隐性负载。图4的左边是一个温度控制子系统，包括了一个高温冷却装置、冷却塔、冷却水泵和室内终端装置，它承担了剩下的显性负载，对室内温度进行控制。其中的高温冷却装置是一个离心冷却装置，它的COP为8.3（设计状况：冷却水的入口温度和出口温度分别为20.5/17.5和30.0/35.0），这比工作在12.7/7的传统冷却装置高很多。至于室内终端装置，如图6所示，工作在“干状态”的风扇线圈安装在餐馆、档案、办公区域，它们占据了温度控制子系统大约81%的制冷负载。在前面部分，我们已经简要介绍了整个THIC系统的布局。尤其是在大空间中作为一个极其重要的设计原则的分层的空调系统，被选作门厅的空调设计，正如图2所示。详细地说，在被占据的空间里（高度不超过2米），17.5的冷却水通过水泵输送到辐射采暖地板进行降温，被处理过的干新鲜空气和室内废气分别从整个空间的底部进入，从中间排出。这样就形成了一个“干空气层”来避免较冷的地板表面有水蒸气凝结。在远离被占据区域的较高空间，从玻璃屏进入的太阳辐射被装饰物吸收，然后热量就从百叶窗等自然通风设备排出了。温度控制子系统和湿度控制子系统可以根据周围环境状况和室内要求分别进行控制。这两个子系统在湿热的气候都要工作；在湿冷的气候下，只有湿度控制子系统要工作；当外界空气足够干的时候，比如11g/kg，外界的空气将过滤后直接进入大楼。据我们所知，冷却空气比通过冷凝给空气除湿要容易得多，因为后者需要的冷源的温度比前者低得多。但是，在目前的THIC系统中，被测的温度控制子系统的COP却低于或等于湿度控制子系统的COP。因此，本部分将着力解决如何改善温度控制子系统的工作效果。根据表4中所示的温度控制子系统中的每个元件的工作情况，我们推荐三个对温度控制子系统进行改进的主要方案：（1）对冷却水泵的频率进行修改；（2）收紧带子，提升冷却塔的工作状况。（3）在干燥的工作环境下，提升FCU的工作状况。前两个方案很容易在建筑内实现，而第三个的实现难度取决于新的FCU产品。总结一下，本文论述了深圳的一个办公大楼的THIC系统的工作情况。液态干燥剂新鲜空气装置用来提供干的新鲜空气，以对室内的湿度进行调节。17.5的冷却水通过水泵输送到辐射面板和干风扇线圈来控制室内温度。一下是根据测试结果得出的结论：（1） THIC系统能提供一个舒适的室内环境，使得室内温度、湿度比例和二氧化碳浓度都在令人舒适的范围内。（2） 整个THIC系统的COP可以达到4.0，其中温度控制子系统和适度控制子系统的COP分别为3.7-4.1和4.1。在测试的办公大楼中，THIC系统的能耗是32.2KWh/(m2 yr)，这也就是说，能源使用效率比传统的空调系统高得多。（3） 我们提出了温度控制子系统的一些改进方法，包括对冷却水泵、冷却塔和FCU的改进。因此，预期的系统COP可以进一步提高到4.4，这与当前使用的空调设备相比可以节省9%的能耗。2 英文原文Performance of temperature and humidity independent control air-conditioning system in an office buildingIn the conventional HVAC system that removes moisture by condensation, air is cooled and dehumidified simultaneously. In most cases, sensible load of building covers the majority part of the whole cooling load while the latent load (moisture load) takes only a small part. However, as the required cooling source temperature of dehumidification is much lower than that of cooling, the chilled water temperature has to be reduced to meet the demand for condensation dehumidification. Moreover, the ratio of sensible load to latent load varies largely due to the changes of outdoor climate, number variance of indoor occupants, indoor equipments and lighting utilization mode and so on. Therefore, the indoor temperature and humidity, the two key parameters, can hardly be satisfied with condensation by the cooling coil only. In practice, the common reaction to the increased humidity is to reduce the set-point temperature and then re-condition the air after passing the cooling coil to the proper temperature, which results in a plenty of energy wastefulness. To avoid the aforementioned problems, temperature and humidity independent control (THIC) air-conditioning system stands out as an appropriate pattern that temperature and humidity can be regulated independently with temperature control subsystem and humidity control subsystem respectively. Besides, the coil temperature for cooling in the temperature control subsystem can be considerably increased, e.g. from current 7 C to 17C, so that improvement on the performance of chillers or even free cooling from ambient could be obtained. Many investigations have been carried out on the hybrid desiccant dehumidification and air-conditioning system, which integrates liquid/solid desiccant units with a conventional cooling system to avoid excess cooling. Liquid desiccant units developed quickly in recent years, for its advantages of dehumidifying at a temperature higher than the airs dew-point to avoid reheat procedure in the system, and regenerating desiccant at a low temperature which can be driven by low-grade heat sources 5,6.Many studies focusing on improving its performance with process optimization have been conducted in depth, such as Yadav 7, DryKor Ltd. 8, and Liu et al. 9. Chen et al. 10 designed an independent dehumidification air-conditioning system with a hot water-driven liquid desiccant and a chiller that provides 1821 C chilled water for an office building in Beijing, which saved about 30% cooling cost compared with conventional system. The performance of a hybrid system tested by Ma et al. 11 was 44.5% higher than conventional vapor compression system at a latent load of 30% and this improving could be achieved by 73.8% at a 42% latent load. Besides, the specific research on the feasibility and performance of the hybrid system in hot and humid regions is promoted.This paper will investigate the real operating performance of a THIC air-conditioning system operated in an office building located in Shenzhen, a modern metropolis in southern China of hot and humid climate. In this THIC system, the liquid desiccant fresh air handling units driven by heat pumps are employed to handlethe outdoor air to remove the entire latent load and supply enough fresh air to the occupied spaces, and the high-temperature chiller that produces chilled water of 17.5 C for the indoor terminal devices (radiant panels and dry fan coil units) is applied to control indoor temperature. The operating principle and performance test results of the THIC system will be shown in this paper, and suggestion for performance improvement will also be included. The THIC system has been put into practice as a pilot project in an office building in Shenzhen, China. This system has been brought into operation in July 2008 and the basic information about the building and air-conditioning system goes as follows. The 5-story office building, as shown in Fig. 1, is located in Shenzhen, China, with total building area of 21,960m2 and the areas of 5940m2, 5045m2, 3876m2, 3908m2, 3191m2 for the 1st to 5th floor respectively. The main function of the 1st floor is restaurant, archive and carport, the 2nd to 4th floors are the office rooms, the 5th floor is the meeting room, and there is a vestibule vertically through up the 2nd to 4th floors in the north of the building. In the vestibule, curtain wall with ventilation shutters in the upper is applied on its north surface, as shown in Fig. 2. The outdoor condition in Shenzhen is rather hot and humid all through the year as shown in Fig. 3. The annual outdoor air relative humidity is about 80% and humidity ratio in summer is as high as 20 g/(kg dry air). The building requires cooling and dehumidificationin a long period of time, and no heating and humidification requirement in winter. Therefore, how to handle the moisture efficiently is a key issue in such a subtropical area. The THIC system serves from 1st to 4th floor with the net airconditioning area of 13,180m2 (total area of 18,769m2), and the5th floor is served by several stand-alone air conditioners so that is not within the scope of our discussion. The schematic of the THIC system is shown in Fig. 4 with the main devices parameters listed in Table 1. The right side of Fig. 4 is the humidity control subsystem, including9 liquid desiccant fresh air handling units that supply adequate dry fresh air into the occupied spaces. As the volume of the supplied fresh air is proportional to the number of people, the pollutants,CO2 and latent heat produced by human bodies can be removed by fresh air. The schematic of the fresh air processors using liquiddesiccant is illustrated in Fig. 5(a), which is composed of a twostage total heat recovery device and a two-stage air handling device coupled with refrigeration cycles. Lithium bromide (LiBr) aqueous solution is employed as liquid desiccant in these air processors. The total heat recovery device is used to recover the energy from indoor exhaust air (return air) to decrease the energy consumption in the fresh air handling process. And in the heat pump driven air handling device, the diluted solution from the dehumidification modules is heated by the exhaust heat from the condenser and concentrated in the regeneration modules, then the hot concentrated solution is cooled by passing through the heat exchanger and evaporator before it enters the dehumidification modules, and lastly used to remove moisture from the fresh air. To make it clear, the air-handling processes are displayed in the air psychrometric chart in Fig. 5(b) where the fresh air first passes the total heat recovery device to recovery the energy from the indoor exhaust air, and then flows into the dehumidification modules to be further dehumidified and cooled before it is supplied into the occupied spaces. In general, the COP of the liquid desiccant fresh air units (total heat removed from the fresh air divided by the power consumption of the heat pumps and solution pumps) can be as high as 5.0 with the following three main reasons: (1) the cooling capacity of the indoor exhaust air is fully exploited to remove heat from the fresh air by the total heat recovery device; (2) both the cooling capacity from evaporator and exhaust heat from condenser are utilized to enhance the air handling processes; and (3) the efficiency of the heat pump is significantly raised since the required evaporating temperature in this liquid desiccant device is much higher than that in the conventional condensing dehumidification system. Besides, as indicated in Fig. 5(b), the supplied air temperature is lower than the indoor air temperature, so the liquid desiccant system can remove some sensible load of the building as well as the entire latent load. The left side of Fig. 4 is the temperature control subsystem that takes up the rest sensible load to control indoor temperature, including a high-temperature chiller, cooling tower, cooling water pump, chilled water pump, and indoor terminal devices (radiant panels and dry fan coil units). The high-temperature chiller is a centrifugal chiller with the rated COP of 8.3 (designed condition: the inlet and outlet temperature of the chilled water and cooling water are 20.5 C/17.5 C and 30.0 C/35.0 C respectively), which is much higher than the conventional chiller operating at the chilled water temperature of 12 C/7 C. As for indoor terminal devices, as shown in Fig. 6, fan coil units (FCUs) operating in dry condition are set up in the restaurant, archive and office regions which serve about 81% of the entire cooling load of the temperature control sub-system, while radiant floor and radiant ceiling panels are applied in vestibule and some office rooms which serve the rest 19%.In the previous sections, the whole THIC system layout has been introduced briefly. Particularly, stratified air conditioning, a key design principle of large space, is selected in the air-conditioning design of the vestibule as shown in Fig. 2(b). Specifically, in the occupied zone (the height within 2m), chilled water with temperature of 17.5 C is pumped and distributed into radiant floor for cooling, and the handled dry fresh air and indoor exhaust air are supplied and expelled in the bottom and in the middle of the space respectively, which forms a “dry air layer” to protect the cold floor surface from condensation; in the higher space that far from occupied zone, solar radiation that enters through glass curtain wall is absorbed by the ornamental decorations in the higher space, and the heat is then carried away by natural ventilation through the shutters directly. The temperature control subsystem and humidity control subsystem can be operated separately according to ambient condition and indoor requirement. The two subsystems operate together at hot and humid outdoor climate; Only the humidity control subsystem operates at cold but humid ambient condition; Outdoor air is directly introduced into occupied spaces after filtering when outdoor air is dry enough, such as 11 g/kg. According to our knowledge, cooling air can be realized more easily than dehumidification by condensation, since the latter one requires lower temperature of cooling source than the former. However, the COP of the tested temperature control subsystem is lower than or equal to that of the humidity control subsystem in present THIC system. Thus, this section will focus on how to improve the performance of the temperature control subsystem. According to the performance of each component in the temperature control subsystem shown in Table 4, three main improvements of the temperature control subsystem are recommended: (1) modifying the frequency of the chilled wa