Study On Performance Of Mechanical Ventilation Reversibly Used Cooling Tower

The main research content of this article is to analyze the performance of the reversibly used cooling tower(abbreviated as: reversibly used tower)and decide the optimal operating conditions.First,the method of combining energy analysis and tritium analysis is used to analyze the heat exchange process between air and water in the reversibly used tower.In the radon analysis method,the radon reference point is determined as the outdoor air dry bulb temperature.It is clear that the working temperature range of the reversibly used tower is: water temperature<dew point temperature.The analysis shows that the heat transfer of the reverse tower is essentially the process of changing the saturated water vapor to condensate water through the transfer of cold energy.The method of combining energy analysis method with tritium analysis method is used to analyze the heat exchange process of air and water in the reversibly used tower.In the radon analysis method,the radon reference point is determined as the outdoor air dry bulb temperature.It is clear that the working temperature range of the reversibly used tower is: water temperature<dew point temperature.The analysis shows that the heat transfer of the reversibly used tower is essentially a process of changing the saturated water vapor to condensate water through the transfer of cold energy.In the experiment of the reversibly used tower,the water side capacity of the reverse tower was used as the index,and the orthogonal experiment was determined to be two factors and six levels.It is determined that the air flow rate is 86.6 g/s,95.2 g/s,97.7 g/s,111 g/s,and 116 g/s;water flow rate is 200 L/h,210 L/h,220 L/h,230 L/h,and 240 L/h for extensive experimental testing.There are 7 parameters for evaluating the performance of the reversibly used tower: temperature difference,high thermal amplitude,thermal efficiency,air condensation rate,radon efficiency,radon loss and capacity.Taking the controlled air flow rate constant at 97.7 g/s and the gradually increasing water flow rate as an example,taking the average water temperature as 16.7 ? and 15.4 ? as the starting points,the changes of various parameters under different water-air ratios are analyzed.When the inlet water temperature is low,the water temperature is more favorable;the water-air ratio has a greater impact on the performance of the reversibly used tower;excessive water flow is detrimental to the performance of the reverse tower;while the water flow is too small,the heat transfer efficiency is Increase,but it is not good for the capacity of the whole tower.Therefore,the performance of the reversibly used tower cannot be judged based on only a single index,and multiple standards need to be considered at the same time to evaluate the tower performance more accurately and objectively.Using Visual C ++ 2013 software for numerical analysis,it was determined that the calculated calculation domain was the packing height,the tower diameter,and the number of nodes was 10.The forward difference method in the explicit format is used to express the quantity to be calculated.The calculated value is compared with the experimental value,and the results show that the error between the calculated value and the experimental value obtained by the model is within 5%,verifying the reliability of the experimental data Taking OC 40 as an example.The TOPSIS method was used for multi-parameter decision-making.It was determined that there were 7 indexes for evaluating the performance of the reversibly used tower,and the number of operating conditions was 50.The entropy weight method is used to calculate the weight of each index,and the relative distance between the positive ideal solution and the negative ideal solution of each working condition and each evaluation index is calculated to obtain the best working condition and worst working condition.The entropy weight method was used to calculate the weight of each index and the decision score was obtained.Combined with the energy efficiency ratio of the reverse tower,the scheme of using the reversibly used tower for reheating was determined.Recommended operation date of reverse tower: july-august;Running time: 9:00-16:00;Environmental parameters are: air dry bulb temperature >26 ?,relative humidity >50%,dew point temperature >20 ?;The reverse tower heating program is suggested to follow the following steps: first,determine the heat needed in the region,the outlet temperature of the heating system is 20 °C,from the water intake temperature to determine the temperature difference between inlet and outlet,the saliva,and the water flow required for heating;The size of the tower is determined according to the heat transfer per unit volume under different temperature difference.According to the recommended average cross section wind speed and water-air ratio under different temperature difference to determine the air flow required to heat.This study provides a theoretical basis for the performance analysis of the reversibly used tower and the study of operating conditions.