Pool evaporation

millzer


Joined: 12/04/2007
Posts: 978

Message Posted:
14/08/2008 15:39

I fear that our communal pool is leaking, so I'm trying to determine roughly how much water our pool should lose due to evaporation in order to compare it to how much water is being put back in.



I did a separate 'bucket' test (not in comparison with the pool level though!), and over a 24 hour period the bucket lost almost 1.5 centimetres due to evaporation. The bucket test was done on my terrace and not at poolside, as I couldn't be sure that someone wouldn't come along and tip it out, so I accept maybe not wholly accurate due to it not simulating poolside conditions.



Anyway, this is my calculation so I am hoping one of the pool experts can verify whether this seems about right, or wrong as the case may be!



Pool is 30 metres X 13 metres, and taking a 24 hour loss of 1.5 CM as per the bucket test this works out at a volume 5,850 litres or 5.85 Cubic metres (1,286.82 gallons)



Does this sound right for evaporation alone, I know it's a big pool but it still seems an awful lot in one day!!



Also, can anyone confirm how much this converts to in 'tons'? If I've done it right one cubic metre of water = one metric ton, so this would work out at;



5.85 cubic metres per day = 5.85 tons x 7 days = 40.95 tons in one week lost due to evaporation!



So, does almost 41 tons per week sound right for evaporation of a pool this size in high summer, as this amount of water at 15 YTL a ton works out at over £1000.00 per month at 230 YTL to the pound.



Any help appreciated, and hoping someone comes on here and tells me I've got it wrong!!



Cheers

Chick-a-Dee


Joined: 16/06/2008
Posts: 342

Message Posted:
14/08/2008 15:47

Cripes .... this is really technical maths wizardry ..... I'll stick to my Sun shine sing a long if I may ......

Laptalocal


Joined: 28/02/2008
Posts: 99

Message Posted:
14/08/2008 15:47

Sorry, I have no idea re your calculations (!), but I have a 10m pool and it costs me 60 ytl every 2 weeks to top it up, so that cost seems really high to me.

orangekazzie



Joined: 31/07/2007
Posts: 1091

Message Posted:
14/08/2008 15:48

it would also depend on how much usage the pool is getting because when people get in/out of the pool they carry water on themselves and also splashing whilst in the pool.

Chick-a-Dee


Joined: 16/06/2008
Posts: 342

Message Posted:
14/08/2008 15:50

And how many people are 'top bombing!!!!!'

graham


Joined: 20/10/2007
Posts: 397

Message Posted:
14/08/2008 15:54

Good advise on this thread.



http://www.cyprus44.com/forums/3065.asp



Graham

MarkVpiazza


Joined: 14/08/2008
Posts: 530

Message Posted:
14/08/2008 16:11

Millzer



I would think your evaporation figure is at the top end, but possible if you are in a windy spot.



A pool is just like washing - a hot windy day is when evaporation happens the most.



You should also allow say 1 litre for everytime someone gets out of the pool, and a certain amount of leakage (I don't think many pools are 100% watertight)



You might like to read this guide I created last year (recently plagiarised on this board by Deecyprus4)



http://trncvillaowners.phpbb3now.com/viewtopic.php?f=18&t=5



Mark

fire starter


Joined: 19/06/2008
Posts: 3401

Message Posted:
14/08/2008 17:23

do you know how thick the pool walls concrete construction are? they should be 12inches or more. most i have seen in the trnc are not that thick. that is probably why its leaking. we are just looking at building one some have purchased some books on the subject. also most communial pools here are not built to the correct size for the amount of people using them when looking at the health and safety issues.

renelapin



Joined: 19/05/2007
Posts: 136

Message Posted:
15/08/2008 11:41

millzer,



the bucket test is not useful. What is evaporation ? Evaporation is water

getting that hot that it turns to steam. Put the bucket beside the pool and

check the temperature a few hours later. The water in the bucket will

have turned much hotter, the temparture of the pool didn't change.



You can't compare the evaporation quotas.



You should check how much water is needed exclusively by the pool, perhaps

by mounting a separate meter.



Rene

ROBnJO


Joined: 30/06/2008
Posts: 1289

Message Posted:
15/08/2008 12:16

I understand that pools used by a large number of children do not appear to lose as much water,...



although it may be slightly discoloured!

MarkVpiazza


Joined: 14/08/2008
Posts: 530

Message Posted:
15/08/2008 12:55

Renelapin



If you would care to read my article, I suggest the bucket be placed on a pool step, i.e. in the pool surrounded by water, so the water in the bucket does not get hotter than the pool water, and thus evaporation rates stay similar.



Mark

TRNCVaughan


Joined: 27/04/2008
Posts: 4578

Message Posted:
15/08/2008 16:33

Hi Millzer,

I calculate that your pool should be using about 5-6 tonnes per week, average. Double that in summer and halve it in winter. If its more than that, it's leaking.



Hi Laptalocal,

You sound like you are getting through about 13 tonnes a fortnight. Your pool is leaking as well.

millzer


Joined: 12/04/2007
Posts: 978

Message Posted:
15/08/2008 19:52

Thanks for all the replies.



Rene, good point about the bucket test. It did seem like an awful lot of water for a pool to lose in evaporation, and 5-6 tonnes average seems much more realistic.



Thanks once again.

millzer


Joined: 12/04/2007
Posts: 978

Message Posted:
16/08/2008 10:42

I meant to say, any other pool experts want to share their opinion? I think Murat from Esentepe pools comes on here sometimes, so what do you think Murat, do you agree with Vaughans estimate of water loss due to evaporation for the size of our pool 30 metre X 13 Metre with a depth from around 1.5 to 1.8 metre?



By the way, Not doubting you Vaughan, just seeking as much opinion as I can.



Cheers

renelapin



Joined: 19/05/2007
Posts: 136

Message Posted:
16/08/2008 14:05

Mark,



I read your article, no doubt -the way you suggest to do the bucket test,

it will work and give correct information on the evaporation quote.



Rene

TRNCVaughan


Joined: 27/04/2008
Posts: 4578

Message Posted:
16/08/2008 14:11

Hi Millzer ,



Not at all, old chap.

I think if you take a look at:

http://www.rlmartin.com/rspec/whatis/equations.htm

I'm sure you'll agree these figures concur with me.

renelapin



Joined: 19/05/2007
Posts: 136

Message Posted:
16/08/2008 17:15

Yes Mark,



that's the way the bucket test works.



Rene

millzer


Joined: 12/04/2007
Posts: 978

Message Posted:
16/08/2008 17:54

Hi Vaughan....Wow....I'll take your word for it on that one lol, but cheers anyway.



MarkVP yes great info on that post re leaky pools, and yes I agree with Rene that's how the bucket test should be done, but as it was a communal pool I'm sure some charlie would have tipped it all out b4 the end of the test, which was why I didn't do it by the pool however with hindsight and taking into account what you said I can see why it was a waste of time doing it the way I did. Thanks again guys for some great info.

MarkVpiazza


Joined: 14/08/2008
Posts: 530

Message Posted:
18/08/2008 16:16

Is anybody in the position to do a test on how much water loss can be attributed to a person getting out of a pool?



test would be

Place weighing scales by the side of the pool (digital probably required)

get on scales dry, with swimsuit on and holding dry towel

take reading of weight

get in pool, get hair wet etc

get out of pool standing on towel to capture all water removed from pool

weigh again



compare difference in reading, and establish water loss, 1kg = 1 litre of water.



Mark

ROBnJO


Joined: 30/06/2008
Posts: 1289

Message Posted:
18/08/2008 17:34

mark



That test is basically flawed!



Men are (usually) hairier than women, but women cover up more of their bits during swimming and often have longer hair.



Due to so many variables, the test would only be accurate if it involved, say, 10 naked women with men waiting around the pool to do accurate measurements on the women before and after immersion.







Any volunteers?

TRNCVaughan


Joined: 27/04/2008
Posts: 4578

Message Posted:
19/08/2008 10:54

Splash out (as it is known) does not contribute much to water loss in a private pool, when compared to evaporation or potential leakage. A large communal pool with lots of children will have more splash out, but evaporation and potential leakage will also be greater, so will tend to remain in similar proportion.