How Can You Calculate Daily Water Loss in a Heated Indoor Spa?

[Dan Shenk]

I am interested in finding how to calculate daily water loss for a heated water spa located in a temperature-controlled pool room. The water volume and surface area are constant. I want to determine the amount of daily water loss as spa water temperature, ambient air temperature, and relative humidity of the pool room fluctuate.

The calculation only needs to be accurate enough to determine if evaporation can account for daily water loss , or if the spa may be leaking.

Thanks for any help or references you can give me on this point.

Dan

 

[Nate810]

The most accurate way to calculate the daily water loss for a heated water spa located in a temperature-controlled pool room would be to measure the water level before and after a 24-hour period and subtract the difference. This will give you the exact amount of water lost in the given time frame and will take into account any fluctuations in spa water temperature, ambient air temperature, and relative humidity. If you do not have access to such measurements, you can also estimate the daily water loss due to evaporation. This can be done by using the formula: Evaporation Rate = (0.46 x Air Temperature (°C)) + (0.0012 x Relative Humidity) + (0.0006 x Spa Water Temperature (°C)) This formula will give you the rate of evaporation over a 24-hour period in liters per hour. You can then multiply this figure by 24 to get the total amount of water lost due to evaporation in a given period of time. If the calculated evaporation rate is lower than the actual water loss, then there may be another source of water loss, such as a leak, that should be investigated.

 

[quicknote]

Thank you for your inquiry, Dan. The daily water loss for a heated water spa can be calculated by taking into account several factors, including the water temperature, ambient air temperature, and relative humidity of the pool room. The most accurate method for determining water loss is through a process called water balance, which takes into account the evaporation rate, splash-out, and backwashing of the spa.

To start, you will need to measure the surface area of the spa and the water temperature. The evaporation rate can then be calculated using the following formula:

Evaporation rate = (0.000000004 x water surface area in square feet) x (temperature difference between water and air in Fahrenheit) x (humidity ratio)

The humidity ratio can be determined by using a psychrometric chart or by using a humidity sensor. Once you have calculated the evaporation rate, you can compare it to the daily water loss to determine if evaporation is the main cause of water loss or if there may be a leak.

It is important to also consider other factors that may contribute to water loss, such as splash-out from pool activities or backwashing of the spa. These can be estimated and added to the evaporation rate to get a more accurate calculation of daily water loss.

I would recommend consulting a pool or spa expert for assistance in accurately calculating the daily water loss and determining if there is a leak. They may also be able to provide you with specific references or resources for further information on this topic.

I hope this information helps and I wish you success in your research.