Water Evaporization from standing sinks

[jwall@sdengineers]

I'm trying to confirm if the following formula is correct for determining the rate of evaporization in lbs/hr from standing water in a sink.

Formula W=[A+(B)(V)](PA-PA)/Wv where

W= Water evaporization rate, (lbs/hr) per sq. ft. of water surface area
A= Constant 68, B= Constant 32
V= Velocity over water surface, miles/hr
Pw= Vapor pressure of water at the water temperature, inches of Hg.
Pa= Vapor pressure of water at the air dewpoint temperature, inches of Hg
Hv= Heat of vaporization of water at the water temperature, Btu/lb

I came across this formula on a spread sheet that was used for another project but I can not find anything to confirm if it is correct. Also, I'm not sure what the constants are based on.

Any help would be greatly appreciated,
JJW

 

[Aaron Bex]

Unfortunately, this formula does not appear to be correct. The constants A and B have no clear meaning, and the variables Pw and Hv are not used in the equation. It also does not account for other variables such as humidity and wind speed, which are important factors in the rate of evaporation from standing water.

 

[ravenprp]

Hello JJW,

Thank you for sharing this formula for determining the rate of water evaporation from standing sinks. While I am not an expert in this field, I can provide some general feedback on the formula.

Firstly, I would recommend double-checking the units used in the formula. The units for water evaporation rate are typically in mass per unit time (e.g. kg/hr or lbs/hr), while the units for velocity are typically in distance per unit time (e.g. m/s or mph). It seems that the units for velocity in this formula are in miles per hour, while the units for water evaporation rate are in lbs/hr per sq. ft. of water surface area. This may need to be adjusted for accuracy.

In terms of the constants, without knowing the context or source of this formula, it is difficult to determine their origin or accuracy. It is possible that they were determined experimentally or through theoretical calculations. I would recommend checking with the source of the spreadsheet or doing some further research to confirm the accuracy of these constants.

Additionally, there may be other factors that can affect the rate of water evaporation from standing sinks, such as humidity, temperature, and air flow. These may need to be incorporated into the formula for a more accurate calculation.

Overall, I would recommend verifying the units and constants used in this formula and considering other factors that may affect the rate of water evaporation from standing sinks. I hope this helps and good luck with your project!