The main goal of this study is to investigate the influenceof the outdoor design conditions selected during sizing ofon air conditioning system. The analysis consists of threemain steps. In the first step, the total cooling loads of asample building are calculated utilizing different outdoordesign conditions such as the data given by ASHRAE [7]and the current design data used by project engineers inTurkey [8]. In the second step, design capacities of the allair central air conditioning equipments selected for thesample building are determined for the various outdoordesign conditions considered in the study. Finally, costanalysis of the air conditioning system is performed forthe cooling season.
2. Description of the sample buildingA high school building was selected in order to conductthe analysis. The sample building is located in Adana, Tur-key (36 590latitude, 35 180longitude and 20 m altitude).Adana, an agricultural and industrial centre and thenation’s fifth largest city, is near the Mediterranean Sea.It is hot and humid in the cooling season. The samplebuilding has three almost identical floors. Fig. 1 showsthe architectural plan of the first floor. The gross area ofthe building is 1628 m2, and the outside surfaces of thewalls are light colored. The long sides of the building facenorth and south. The sample building is used as a highschool and is occupied between 08:00 and 17:00 h. The highschool has 224 students, 15 teachers, 4 officers and 3 labor-ers. The building has 14 classrooms, 3 laboratories, 5 offi-ces, 1 library, 1 computer room and 3 corridors. Thebuilding complies with the insulation requirement imposedby Turkish Standard-TS 825, ‘‘Thermal Insulation in Buildings’’ [9]. Table 1 shows the overall heat transfer coef-ficients of the high school envelope. In the analysis, the various outdoor design condition datasets of Adana were used. Details of the data sets are given inTable 2. As shown in the table; there are five data sets. Thefirst data set is the current outdoor design conditions (CUR-RENT) [8] used by project engineers in Turkey. The secondand third data sets are outdoor design conditions for cooling(ASHRAE_04, ASHRAE_1, ASHRAE_2) and evapora-tion systems recommended by ASHRAE [7] at the 0.4%,1% and 2% frequency levels (ASHRAE_EVAP_04, ASH-RAE_EVAP_1, ASHRAE_EVAP_2), respectively. Thefourth data set is the maximum dry bulb and wet bulb tem- peratures, which are given by ASHRAE [7] at the 0.4%, 1%and 2% frequency levels (ASHRAE_MAX_04, ASH-RAE_MAX_1, ASHRAE_MAX_2), respectively. The lastdata set is the daily maximum dry and wet bulb tempera-tures of July 21st (DAILYMAX) as design day data, whichare calculated from the meteorological data obtained fromthe Turkish State Meteorological Service (Turkish initials‘DM_ I’).
The sample building is conditioned by an all air condi-tioning system with constant air volume (CAV). The systemcommonly consists of an air handling unit (AHU), air cooledchiller system, supply and return fans, duct and controlunits. Fig. 2 is a schematic of an all air central air condition-ing system showing typical operating conditions. Thereturned room air (state R) is mixed with the required out-door air (state O) at the air handling unit. The mixed air(state M) passes through the cooling coil. The outdoor airis usually warmer and more humid than the return air undertypical operation conditions. Therefore, the cooling process generally involves both cooling and dehumidification, withthe conditioned air leaving the cooling coil at state (S). Thecooled and dehumidified air leaving the coil at state (S) isthen supplied to the conditioned space at constant air vol-ume, which is at state (R), to complete the cycle. Fig. 3 showsthe state points of air during the process for summer opera-tion of the air conditioning system on a psychometric chart.
摘要：室外设计的条件是建筑节能的重要参数。不正确的选择户外设计条件，结果会影响舒适性和能耗。为了证明这个假设，冷负荷和空调设备的负载和容量位于阿达纳的一个示范楼内，土耳其使用不同的室外设计条件推荐ASHRAE计算，目前在土耳其使用设计数据和七月二十一日的日最大的干、湿球温度，这是公认的标准日。从这项研究考虑了不同的户外设计条件下得到的冷却盘管的能力对比。同时也进行空调系统的成本分析。可以看出，室外设计参数的选择是建筑物的负荷和空调设备的冷却计算设计至关重要。 供热通风与空气调节系统英文文献和中文翻译(2):http://www.751com.cn/fanyi/lunwen_22550.html