Calculating a closed-type cooling tower using the box heat exchanger software BoxHeater – an example

This result of yours still needs to be verified. Judging from the allocated area and air volume, the equipment configuration is imbalanced – the area is too large while the air volume is too small. A closed-type cooling tower requires not only the calculation of area and air volume, but also consideration of the power consumption of the fan and the amount of water used for spraying. The interface you have is only a semi-finished version and needs further improvement. It’s just my personal opinion; please don’t criticize if you don’t agree.

This post was last edited by wiseboy on 2022-3-7 at 16:33. What you said is correct in principle; it’s just that the amount of liquid evaporation has already been calculated, and you might not have noticed that. The spray volume is just a multiple of this evaporation volume. This is also equipment that has been verified by professional manufacturers and is used in manufacturing. There are 4 in total, and this is just one of them. And won the bid. As for the large area you mentioned, it has been adjusted by the manufacturer; the wind speed is 2.23 m/S, and that is the speed required by the manufacturer, with the area corresponding to this speed. Secondly, the air volume corresponds to the total pressure of the fan they choose. Thirdly, the amount of air flow is calculated based on the thermodynamic gas-liquid equilibrium related to the evaporation rate, rather than being estimated based on experience. Furthermore, this is not either a semi-finished product: the software is only used for calculating cooling towers; it is a specialized heat exchanger calculation software with many functions, such as air coolers, economizers, and GGH heat exchangers. . . . That’s all; I don’t have time to say more.

OP, the amount of liquid evaporation is calculated based on heat, and it can be determined as an independent parameter; it has no direct relation to the amount of water sprayed. As for verification by professional manufacturers, I’m not familiar with the logical relationships involved, so I won’t comment much on it. Winning the bid does not mean that your proposal is reasonable, nor does it mean that it will meet the design requirements. Once the air volume is determined, the most important thing is to determine the static pressure loss of the closed-type tower, rather than the total pressure. Once the air volume and total pressure are fixed, different fan diameters and powers can meet the requirements. Given this wind speed, the static pressure drag is low. The process of determining airflow volume and area is itself a trial calculation process. Your selection interface for closed-loop cooling towers is indeed a semi-finished product. For designers, parameters such as the equipment’s air volume, static pressure, fan power, flow rate and power of the spray water pump, the length and width of the equipment, its internal dimensions, the number of coils, the process flow, flow velocity within the pipes, and resistance are all interconnected. Two key parameters have been determined; other parameters will not be considered in detail, as this does not align with the designers’ approach

This post was last edited by wiseboy on 2022-3-8 at 14:18. It has no direct relation to the spray volume. The calculation of the spray volume takes several factors into account; several methods can also be used: 1. Generally speaking, evaporation accounts for about 2.0% of the total spray volume, and this value can be used to calculate the spray volume – it’s not an independent parameter as you mentioned； 2. Some people calculate it as a multiple of the heat quantity Q: total spraying volume = kQ. 3. Some people use the spray density to estimate the total amount of spray applied; this spray density ranges from 8 to 20 m3/(m2·h), which is a wide range. It isn’t an independent parameter as you mentioned. Most manufacturers choose a value of 15 m3/(m2·h). 4. When fillers are used, the spray density requirements specific to those fillers must also be met. More precisely, there are formulas for determining the minimum spray density required for different fillers (refer to the relevant standards for packed towers) ； Therefore, each manufacturer has its own persistences. Therefore, I did not calculate the spray volume. It can be said that many “experiences” are only superficially understood, and what is successful is not necessarily the best approach. The winner of the bid is not necessarily the best, but I checked its spraying volume: it uses the lower limit. To repeat once again: this software is a heat exchanger software, not a specialized software for closed-loop cooling towers; there is no such thing as a semi-finished product.

Well, your explanation regarding the amount of water used for spraying is very thorough, and I agree with it for the most part. I give up on the rest; no further discussion.

It’s all about dealing with things as they are, striving for excellence. Discussion is welcome.