外文翻譯---關(guān)于綜合運(yùn)用局部和整體儲存方式的儲冰系統(tǒng)的應(yīng)用-文庫吧
2025-01-02 23:35 本頁面
【正文】 cases (1), (2) and (3) respectively. . Combined strategy system In a bined system where two sets of chillers operate in partial and full strategies atthe same time, it is important to find the minimum bination chiller size that will satisfy the cooling load at a set of conditions. These conditions are the evaporating and condensing pressure and temperature and the number of onpeak hours during which only the partial chiller is kept running. The procedure adopted in this study in finding the minimum chiller size may be summarized as follow: (a) An initial assumption of the partial chiller size is to be made. The chiller size thus assumed should be related, some how, to the cooling distinct values of the cooling load are the maximum and the average value and the later is chosen in this study. Hence the initial partial chiller size will be the average cooling load multiplied by a certain, arbitrarily selected, factor (Fp ). (b) Since aircooled chiller is used, its condensing temperature would vary according to inlet ambient air temperature. Therefore the initial partial chiller size would be based on the condensing temperature at which maximum cooling load occurs. (c) Chiller capacity is then determined hourly and for the daily cycle at the different existing condensing temperature. (d) The difference between the daily cycle cooling load and the daily total partial strategy chiller capacity would be met by the full strategy chiller. The size of this chiller is assumed to be equal to the average cooling load multiplied by a factor (F) and must equal to the difference indicated above. If this condition is not satisfied then another value of (Ff) is selected. (e) The bined strategy chiller size obtained by the initial run with the assumed (Fp) and calculated (Ff) may not be the an iteration procedure is adopted and the factor (Fp) is changed progressively until a minimum chiller size is obtained. (f) In order to find the relation between optimum chiller size and cooling load at different onpeak hours, the above procedure is repeated for each onpeak period (starting from six and endingwith zero onpeak). For each onpeak period an optimum chiller size is to be determined. . Calculation procedure To start the calculation procedure, the size of the partial strategy chiller should be defined first. It shall be assumed that the size (Q sp) equal to the average cooling load (q av) for any of the three cases multiplied by an arbitrarilyselected factor (Fp). Qsp=q av .Fp (KWh) (1)Ref. [1] reported that rating of air cooling condenser is based on the temperature difference between dry bulb temperature of the air entering to the coil and the condensing temperature corresponding to the pressure at inlet. The air temperature inlet to the coil is typical of Baghdad area at the 21st of July. Ref. [2] stated that the evaporating temperature of a refrigeration system used for ice storoage, ranges between –4 and –12 C. In this study–8176。C is used. Thus Qsp calculated by Eq. (1) shall be based on the maximum condensing temperature occurring during the daily cycle. Accordingly and with evaporating temperature indicated above, the partial chiller pressor displacement (V) is determined where ηmnis the minim
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