Engineered design tools for swimming pool system designers, you can complete design in just a few clicks... find filtration pump flow rate, number of filter, balance tank volume, backwash tank volume, number of skimmer, amount of chemical required, chlorine solution dilution, heat-up heat, heat losses, etc.

Aim: creating a mobile design environment for the practising engineers & designers in today's mobile world.

Results: Instant solutions at your fingertips.

Highlights:

• calculates filtration pump flow rate, filter sizing, balance tank, backwash tank, skimmer, etc.

• built-in selections like turnover rate, filter type, filter area, filter loading rate, pool shape, pool area and volume calculation.

• design tool modules include:

1. Hypochlorite chlorination calculation.

2. Pool heat-up heat calculation.

3. Pool heat losses calculation.

• in SI-IP Units. 

(see downloadable screen shot in SI units)

Swimming pool water requires heating in two circumstances: 

(1)  during the operation, the pool is losing heat as a result of evaporation, convection, radiation and conduction (See Example 3). The magnitude of the evaporation + convection losses usually exceeds 80% of the total heat losses.

(2) during the initial heat-up (See Example 4).

In designing a pool heater, the designers usually have to evaluate the heating requirements for these 2 circumstances to make a fairly accurate estimate of the heater capacity. An understanding of the various losses is important.

Calculation Example 3: Pool heat losses . . .  

You are tasked to estimate the pool heat losses for a condominium lap pool (82 ft length x 33 ft width x 4 ft deep).

Given design conditions:

- Outdoor air conditions: 75 oF / 50% RH.

- Pool initial water temperature: 65 oF.

- Pool heated water temperature = 80 oF.

In doing the calculations, you have made the following assumptions:

• wind speed = 7 mph.

• conduction heat loss = 3% of total losses

• ignore fresh water make-up heat loss.

Heat losses from a swimming pool are mainly attributed to the following four mechanisms:

• Evaporation from the pool surface.

• Convection from the pool surface.

• Radiation from the pool surface.

• Conduction through the pool walls.

Evaporation Loss  

The rate of evaporation is estimated from the following equation [ASHRAE 2011]:

Wp = [A(Pw-Pa)(0.089+0.0782V)]/Y

where

Wp = evaporation of water, kg/s

A = area of pool surface, m2

Pw = saturation vapour pressure at pool water temperature, kPa

Pa = saturation vapour pressure at ambient air dew point temperature, kPa

V = air velocity over water surface, m/s

Y = latent heat required to change water to vapour at surface water temperature, kJ/kg

The evaporation heat loss is then calculated as follows:

Qev = (Wp x Y) x F

where

Qev = evaporation heat loss, kW

F = activity factor

Convection Loss  

The convection loss is calculated using the following equation [ASHRAE 2011]:

Qcv = A x hcv x (Tp - Ta)

where

Qcv = convection heat loss, W

A = area of pool surface, m2

hcv = convective heat transfer coefficient, W/(m2.K).

[If option for Fixed convective transfer coeff. is unchecked, hcv is computed as 1 + 0.3V btu/(h.ft2.oF) in the aPocketPool program; V in mph.]

Tp = pool temperature, oC

Ta = ambient temperature, oC

Radiation Loss  

The radiation loss is calculated using the following equation [ASHRAE 2011]: