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摘 要:传统空调由于基于减少能耗的考虑将室外新鲜空气的送入量减为零或限制在很小的比例,因此室内有害物质由于得不到新风的充分稀释而浓度不断提高,引起了室内空气品质(IAQ)的恶化。因此增加新风量以改善室内空气品质显得非常重要,全新风空调机组运行时可以稀释细菌的浓度,改善室内空气品质。然而随着能源日趋紧张,节约能源已成为各界人士的共识。在建筑物的空调负荷中,新风负荷占相当大的比例。同时从室内排出的空气中大量的热(冷)量排放到大气中,不仅给城市空气造成热污染,同时也浪费了大量的能源。利用室内排风做部分冷凝的节能型全新风空气处理机组,采用“小风量大焓差”以及“利用排风节约能源”的设计理念,与回风型空调机相比,制冷量相同的机组,其风量仅为回风空调机的30%-50%,处理的空气焓差为回风空调机的2-3倍,意味着满足相同的负荷要求时全新风机组的送风温差更大,且利用了室内排风,冷凝温度下降机组性能得以提高。全新风机组作为独立新风系统时可与多联机空调系统、辐射供冷(暖)空调系统等配合使用。本文以一台额定风量为4000m3/h的大焓差利用排风做部分冷凝型全新风机组为例,运用理论计算和设计与实验比较的方法,详细介绍设计一台利用排风做部分冷凝的全新风空调机组的方法和步骤。机组以制冷设计为主,论文首先进行了理想循环和实际循环的热力计算,不考虑风机散热等的影响,能效比可分别达到5.06和3.77。蒸发器和冷凝器都采用翅片管式,采用控制过热度和过冷度为定值的方法设计蒸发器和冷凝器的传热面积,蒸发器的名义传热面积为46.25m2,冷凝器的名义传热面积为149.88m2。为安全起见,为机组选择了两台谷轮公司产的相同型号的封闭式压缩机,名义制冷量满足要求。为机组的阀门和附件进行了设计或选型,并对机组提出了控制要求。最后对课题研究过程进行了总结,并提出了本课题还需深入的后续研究。 关键词:全新风,排风冷凝,空调机组,设计
Abstract:The traditional air conditioning devices are designed to reuse the gas cycling in the rooms and confined the fresh air to a small proportion So indoor harmful substances without fully diluted concentration of fresh air and improve continuously.It causes indoor air quality (IAQ) worsely. It is vital important to increase fresh air in the rooms to improve the indoor air quality, which can be achieved by operating an overall fresh air conditioning unit. However,with increasingly nervous energy, save energy has become the consensus of people from all walks of life. In building the new-wind load in air conditioning load, accounts for a considerable proportion. Meanwhile from indoor air exhaust (cold) a lot of heat quantity emissions into the atmosphere. Not only give urban air pollution caused by heat, also wasted a lot of energy. The use of indoor air exhaust energy-saving overall fresh air conditioning unit takes ‘little air volume, great enthalpy difference’ and “use exhaust to save energy “as it’s designing eidos. Compares to an air-return conditioning unit, when they have the same refrigerating capacity, air processed by the overall fresh air conditioning unit is about 30%~50% of the latter’s, of which the enthalpy difference is 2~3 times. It means that the overall fresh air conditioning unit is larger in sending-air temperature difference. And use indoor exhaust, Condensate temperature drop unit performance can be improved.The overall fresh air conditioning unit may cooperate with VRV system, radiate floor system and etc. the thesis took an overall fresh air conditioning unit with a rated air volume of 4000 cubic meter per hour for example, used theoretical calculation and designing to particularly introduce the methods and steps to design an use of indoor air exhaust energy-saving overall fresh air conditioning unit with great enthalpy difference.The conditioning unit was mainly designed under refrigerating conditions, thermal calculation of both ideal and practical cycle were progressed firstly. The energy efficiency ratio (abbr. EER) is 5.06 and 3.77 of the ideal cycle and the practical cycle, respectively, neglecting the effecting of the heat produced by fans. The evaporator and condenser were fin-tube, the heat transfer area of the evaporator and condenser were calculated by confining the super heat and sub cooling to a fixed value, the heat transfer area of the evaporator and condenser under named conditions are 28.9 square metrers and 118 square metrers, respectively. Take safe as consideration, the comprosser of the unit is equipped with two ones produced by coopland with the same type, the named refrigerating capacity of the two comprossers meet the requriments. The valves and accessories were designed or selected, and automatic control requirements and strategies were described, too. It is concluded at the final of the paper, and it points out what needs further studies. Key Words: overall fresh air; exhaust condensing; air conditioning unit; designing |