Pool Evaporation formula ??????? Any one have advice please

skeeds2000


Joined: 18/10/2008
Posts: 112

Message Posted:
18/06/2010 09:26

Hi Looking for some help trying to work out how much water should be lost due to evaporation. A friend of mine said this could he could work this out using the Molliers Equation here we go :-



The "Mollier Equation"



SURFACE AREA (m2) x HUMIDITY RATIO IN SATURATED AIR (kg2) x HUMIDITY RATIO ın AIR (kg2) x VELOCITY of AIR ABOVE SURFACE (m2).



When broken down this equation works as follows:-



3 cubic centimetres per m2/hour/day at 28 degrees C.



Therefore on a 10x5m pool that you have wıth a surface area of 50m2, on an average day here in Cyprus wıth 9 hours of sunshine, a pool wıll lose approximately 380 cubic centimetres which equates to 2660 cc (2.6 tonnes) per week.



Could anyone please give their advice on this equation or is there a preferable way to measure evaporation.



Many Thanks in advance.



Skeeds2000

zerochlor


Joined: 03/04/2009
Posts: 4024

Message Posted:
18/06/2010 09:38

I think vaughan from octopus pools will give you a formula,but i feel you already have it with what you wrote.

TRNCVaughan


Joined: 27/04/2008
Posts: 4578

Message Posted:
18/06/2010 11:31

Industry norm suggests, from observation and experience, that a pool will loose between 30% and a 50% of its water in a year. Daily rates vary according to air temperature and wind speed.



If we look at at worse case scenario (50%), a 10x5m pool containing about 100 tonnes of water, including the balance tank, will lose about 50 tonnes in a year or about 1 tonne a week, average. Evaporation rates tend to be twice as high in summer as they are in winter, so 2 tonnes per week in summer isn't exceptional. Please bear in mind that this is worse case scenario so it should be less rather than more.



e.g. A pool with an 8 tonne balance tank (2x2x2m) that needs filling more often than monthly suggests that your pool leaks.



But that's another story.....

StGeorgeI


Joined: 27/08/2009
Posts: 973

Message Posted:
18/06/2010 12:22

We have to top up our 8 ton balance tank about every 3 weeks... that is with using the pool, backwashing and evaporation!



Cheers,

G

TRNCVaughan


Joined: 27/04/2008
Posts: 4578

Message Posted:
18/06/2010 14:49

G,



I think you may find you have a leak.



Take the pool off of overflow and put it on main drain. Watch the water level in the pool and if it falls back below the coping stones and then down the tiles in just a few days, you have a leak. Check the water level in the balance tank at the same time and see if that falls.

ataturk


Joined: 09/09/2008
Posts: 712

Message Posted:
18/06/2010 18:57

I have to disagree here. We have to top up our pool on a regular basis during the summer due to backwashing, evaparation and the loss of water due to people using the pool (especially our kids). I know we def dont have a leak as I have tested the pool n the winter (best time as there is little or no evaporation ) and the pool doesnt lose a drop. I think yuo have to take into consideration the size of the pool, how much sun its see all day, backwashing and loss due to people using the pool.



Our pool was extensively waterproofed during construction and didnt lose a drop, I think these figures depend on a lot of factors as some countries are hotter than others and I dont think you can generalise

Groucho



Joined: 26/04/2008
Posts: 7993

Message Posted:
18/06/2010 21:29

If the loss is greater in the summer then that's definitely evaporation. You can reduce this by up to 95% by having a well-fitting pool cover....



We have used one for three years and it works.

RoxyBob


Joined: 13/07/2009
Posts: 205

Message Posted:
19/06/2010 06:24

Could anyone recommend someone who could supply and fit a well-fitting pool cover for a 10 x 5 metre pool.



What would the cost be?

Groucho



Joined: 26/04/2008
Posts: 7993

Message Posted:
19/06/2010 08:10

RoxyBob



You buy one slightly larger and trim to fit with a pair of scissors. The solar ones (that heat the pool to extend your season) are made of a very strong industrial 'bubble-wrap' and I think the pool shops can supply them. I don't know the cost but I would guess at somewhere around £150 for the cover. Many folk have bough in the UK and shipped over...



A roller mechanism to wind in the cover and store it is very convenient and tidy.



Note: You also need a cover for the rolled up cover, this prevents the sun from damaging it - when rolled up the solar magnifiers are piled on top of each other and the core temperature of the cover will be greatly increased causing damage. You can get one made at any of the shops that make lounger cushions from plastic coated canvas type material. I can recommend Hay-Hay in Karakum... in the parade of shops next to the K-Pet garage. Ours cost 70TL made.

downunder


Joined: 24/06/2010
Posts: 32

Message Posted:
27/06/2010 03:48

check your gutters, after the capping stone there is a 10cm travertine than guttering and than another 10cm travertine, if there is cracks in the filling than you should be checking your gutters for any minor cracks. if the tile that contains the light caps is wet than the lights have a small leak that pushes it up under the travertine.

Check these in case..