مطالعه طراحی و رتبه بندی جامع از انواع کولر آبی و کندانسورها. قسمت دوم. تجزیه و تحلیل حساسیت

Sensitivity analysis can be used to identify important model parameters, in particular, normalized sensitivity coefficients; by allowing a one-on-one comparison. Regarding design of evaporative coolers, the sensitivity analysis shows that all sensitivities are unaffected by varying the mass flow ratio and that outlet process fluid temperature is the most important factor. In rating evaporative coolers, effectiveness is found to be most sensitive to the process fluid flow rate. Also, the process fluid outlet temperature is most sensitive to the process fluid inlet temperature. For evaporative condensers, the normalized sensitivity coefficient values indicate that the condensing temperature is the most sensitive parameter and that these are not affected by the value of the mass flow ratio. For evaporative condenser design, it was seen that, for a 53% increase in the inlet relative humidity, the normalized sensitivity of the surface area increased 1.8 times in value and, for a 15 °C increase in the condenser temperature, the sensitivity increased by 3.5 times. The performance study of evaporative condensers show that, for a 72% increase in the inlet relative humidity, the normalized sensitivity coefficient for effectiveness increased 2.4 times and, for a 15 °C increase in the condenser temperature, it doubled in value.

The validated mathematical models of evaporative coolers and condensers are used to perform a sensitivity analysis of important response variables. In terms of designing evaporative coolers, the sensitivities are not affected by the value of the mass flow ratio. Furthermore, the surface area (A ) is most sensitive to changes in the outlet process fluid temperature (t p,out) followed by the inlet process fluid temperature (t p,in). Also, a comparison of the influence of both parameters on the response variable, in this case, indicates that it becomes closer to being the same at lower inlet relative humidities and for values of the outlet process fluid temperature (t p,out) that are closer to the inlet process fluid temperature (t p,in). In rating evaporative coolers, effectiveness is most sensitive to the process fluid flow rate View the MathML source(m˙p) and inlet process fluid temperature (tp,in), respectively. Also, the process fluid outlet temperature (tp,out) is most sensitive to the process fluid inlet temperature (tp,in). Higher relative humidities at the inlet decrease sensitivity of the response variables investigated. The results are also indicative of the fact that the selection or changes regarding the ambient conditions do not reverse the order of importance with respect to input variables. Regarding evaporative condensers, the plots show that the sensitivities are not affected by the value of the mass flow ratio and that the condensing temperature seems to be the most important factor in design as well as rating. For evaporative condenser design, it was seen that for a 53% increase in the inlet relative humidity, the normalized sensitivity of the response variable increased 1.8 times and, for a 15 °C increase in the condenser temperature, the sensitivity increased by 3.5 times. In performance rating of evaporative condenser, it was noticed that for a 72% increase in the inlet relative humidity, the normalized sensitivity coefficient increased by 2.4 times and, for a 15 °C increase in the condenser temperature, the sensitivity doubled.