Thermodynamics swimming pool question

1. May 1, 2010

stevex23

1. The problem statement, all variables and given/known data

You are asked to design a heating system for a swimming
pool that is 2 m deep, 25 m long, and 25 m wide. Your
client desires that the heating system be large enough to raise
the water temperature from 20°C to 30°C in 3 h. The rate of
heat loss from the water to the air at the outdoor design conditions
is determined to be 960 W/m2, and the heater must also
be able to maintain the pool at 30°C at those conditions. Heat
losses to the ground are expected to be small and can be disregarded.
The heater considered is a natural gas furnace whose
efficiency is 80 percent. What heater size (in Btu/h input)
would you recommend to your client?

2. Relevant equations

3. The attempt at a solution

2. May 1, 2010

jack action

Ewater = m * cp * T

P = E / t

Pneeded = Pheated + Plosses

3. May 2, 2010

stevex23

Do i calculate the Energy at each temperature then take the difference?

4. May 2, 2010

Yes.