I have found this graph an excellent tool to illustrate the expected energy loss of a constant depth pool based on standard summer parameters. However these parameters are variable day by day; humidity, the wind chill effect and the extent of moving water around the pool all have an effect on the heat loss and the increase or decrease of the heating demand of the pool.
For an example:
With outdoor air temperatures of 15 degrees a 10m x 5m pool covered for 20hrs/day will lose 150watts/m2/hr - 7.5kw/hr. This means that the pool requires 7.5kw/hr to maintain its set water temperature of 27 degrees. If you wanted to increase the pool temperature then you would need to provide <7.5kw/hr to move the temperature up.
What this graph especially highlights is the extent of heat lost when the pool remains uncovered. The same pool uncovered would lose 36kw/hr, which in most domestic applications means the heating source running constantly to try and maintain the temperature.
What we can learn from this?
· Keeping the pool covered when not being used is very important
· With new builds it is important to consider ground conditions when completing the dig. Dewatering the site will have a long term saving on the running costs.
· Consider your pool use and length of season carefully before deciding on the correct heater to install. There is no point installing a heat pump with 15kw of output if you want to be swimming in a uncovered pool late in the season, where the heat loss is greater than the heat pumps output.
