The evaporation rates of occupied and unoccupied Swimming Pools have been measured to derive empirical equations for calculating loss. Three references are:
1. Smith, Charles C., George O.C. Lof, Randy W. Jones, "Rates of Evaporation from Swimming Pools in Active Use", ASHRAE Transactions, Volume 104, 1998
2. Smith, Charles C., George O.C. Lof, Randy W. Jones, "Measurement and Analysis of Evaporation from an Inactive Outdoor Swimming Pool", Solar Energy, Vol. 53, No. 1, pp. 3-7, 1994
3. Shah, Mohammed, "Calculating Evaporation Rates from Indoor Water Pools", HPAC Engineering, March 2004
A spreadsheet tool for estimating the heat loss due to evaporation from an indoor pool is available at http://www.energyideas.org/documents/spreadsheets/IndoorPoolCalc.xls.
This tool is based on the reference above by Shah.
The Rate at which a pool evaporates depends on the relative humidity in the air surounding it.
Heating a pool will increase the rate of evaporation from that pool.
It depends a lot on the temperature and humidity. Here in Southern Arizona it is 110 degrees and 10% humidity (hot and dry) right now, and my pool loses about an inch every three days or so. Wind is also a major factor in evaporation. The quicker the moisture is pushed off the top of the pool the faster it is replaced with more. Windy equals increased evaporation rates.
Approx. 1.5" to 2" per wk.
Evaporation rates primarily depend on surface area, not volume. All that really matters is the square feet of surface area that are exposed. Evaporation rates in Florida can range from 1/10 of an inch per day in the winter to upwards of 3/4 of an inch in the summer.
The evaporation rate of an indoor swimming pool has many factors to consider. 1.) How large is the pool? 2.) What temperature are you keeping the pool water at? 3.) What temperature are you keeping your poolroom at? 4.) Are you using a pool cover? An example would be..... If you have a 300 sq. ft. pool and are keeping the pool at 82 degrees and the room at 84 degrees your evaporation rate would be 10.35 pounds per hour at a static level (no activity). If you do have an indoor pool or are considering having an indoor pool you will need to use mechanical dehumidification to handle the evaporation rate of your pool to protect the structure. Please email me direct if I can further assist you in that area. Regards, Michele Environmental Pool Systems www.dry-air.com
A dark pool liner might cause a very small increase in water evaporation, but nothing significant. The dark pool liner will raise the water temp a bit which, in turn, may increase the evaporation rate. But, the evaporation rate is much more dependent upon the air temperature and humidity than on the water temp, so the increase in water temp would only have a very small effect on the overall or net water evaporation rate. Hope this helps ... yes, it will, and it could be a significant increase.
The color of water does affect the evaporation rate because the red water is more dense then regular clear water.
Wind, humidity, and temperature
The National Weather Service uses a large water pan with a diameter of 4 feet. They measure the drop in water level in one day, fill it back to the level it was before and measure the level drop the next day. They and others do this all over the United States. Others do it throughout the world. The Weather Service reports the evaporation at each location, each day, and sum all these daily values up to obtain an annual evaporation rate in inches. All the data through the US is collected and compiled into an annual evaporation map. Looking at the annual evaporation map one can find the average annual evaporation rate for any location. It is roughly 100 inches for Tucson, Arizona. The evaporation rate varies with temperature, wind speed, sunshine, and relative humidity. The evaporation rate also varies throughout the year. A rough daily rate is given by dividing the annual rate by 365 days. Rough daily evaporation rate = Annual Evaporation rate / 365 For Tucson the rough evaporation rate is 100 inches/365 which is about 1/3 inch per day. Swimming pool If we use this rough evaporation rate, we can find how much a swimming pool water level might drop in 5 days Total surface drop = (5 days) (daily evaporation rate)
Eventually, all of it if not replenished. The rate of evaporation depends on local climatic conditions.