wrote:

I've seen a number of 3kw pool heaters on ebay for about £90. They're
for use in large paddling pools up to 15ft in diameter. e.g.:
http://cgi.ebay.co.uk/ws/eBayISAPI.d...2981 615&rd=1

My pool is a Bestway Fast Set 10ft circular pool with external pump and
filter, and the water height is approx 2ft.

So I'm wondering if anyone here has had experience of these heaters in
this type of pool, and whether its really going to heat a 10ft x 2ft
circular pool.

I've got a pool cover too, for what it's worth.


No experience necessary, just basic physics.

Your pool contains ~ 5m^3 of water, or 5000 litres. This has a mass of
5000kg.

A 3kW heater provides 3000J/s.

The specific heat capacity of water is about 4200 J/(kg.K)

So to raise the temperature of your 5000kg by 1 Celcius we need 21MJ.
Your 3kW heater would take just under 2 hours to deliver this. So if
you're aiming for a 5 Celcius rise, it'd take just under 10 hours.

And this is before you factor in conductive and evaporative losses.


--
Grunff