Skip to main content

.TT pocketEngineer softDesign

... pocketEngineer software for mobile design

pocketEngineer software  animated gif (free)  email me  buy now  thoughts   
...Ductulator Plus+
...aDuctulator (And)
...aBattMV (And)
...aKitchenExhaust (And)
...tRod Sizer (free)
...pocketPipe Sizer
...aPipeSizer (And)
...multi Pipes PD (And)
...aPocketGas (And)
...rhoAIR (free)
...aRhoAIR (free) (And)
...aPsychroAC (And)
...AirTAB superEZ
...Qcool Check
...aCriticalVel (And)
...aPocketPool (And)
ePF Loop Pdrop
...hydrant pressure drop
...Pumping Mainline
Rethink, Reinvent apps
...CurveFit Tracer
...gas suppression
...CA ring main Pdrop
the home of .TT pocketEngineer softDesign - where pocketEngineer software lives...
Dear customers & visitors, as Microsoft is closing down its SharePoint soon, .TT pocketEngineer softDesign is relocating its home to Google site at
 swimming pool pump and filtration calculator on Android (aPocketPool r2.0)

swimming pool filtration system, pool heat-up and heat losses, pool chlorination, and more . . .




To take a glance at all pocketEngineer software and OS requirements, click Overview.


 a PocketPool : a design tool for swimming pool system designer 

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.



- 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:

a) Hypochlorite chlorination calculation.

b) Pool heat-up heat calculation.

c) Pool heat losses calculation.


- "save-to-file" function with built-in result file viewer.


- in SI-IP Units.




  Calculation Example 1: 

Pool filtration sizing . . .  

Size the pool filtration system for the following pool.



W=33', D1=4', D2=6', L1=16', L2=16', L3=50'



The following design calculations are done with aPocketPool program:  

Worked Example (in IP units)


Pool Filtration Calculations

*** inputs ***
Pool area = 2706 ft2 (using built-in area & vol. calculator)
Pool volume = 109605 USgal

Bathing load = 25 ft2/p
Bather weight = 140 lb
Wave action/displacement = 0.065 ft

Turnover rate = 6 hr.

Filter type = D.E. filter
Filter loading rate = 2.5 gpm/ft2
Filter area (each) = 72 ft2

Backwash rate = 2.5 gpm/ft2
Backwash duration = 3 min.


*** results ***
Pump flowrate (USgpm) = 304.5

Filter area required (ft2) = 121.8
Nos. of Filter = 2

Wave displacement vol. (USgal) = 1316
Bather displacement vol. (USgal) = 1816
Backwash tank vol. (USgal) = 913

Balancing tank vol. (USgal) = 4045







 Calculation Example 2: 

Chemical chlorination dosing. . .  

A pool water test has determined that a total chlorine dosage of 2 ppm (mg/L) is required to treat the pool water. The calcium hypochlorite has 65% available chlorine. Determine the weight of chemical (solid form) needed.


Also a 5% concentration solution needs to be prepared. Find the volume of the diluted chlorine solution.


The hypochlorite chlorination calculations presented below are based on the pool volume of 260 m3.


 *** Chlorine (Cl2) dose requirement ***
Cl2 dose = 2 ppm


*** Chlorine (100% strength) needed ***
Pool volume = 260 m3
Cl2 dosage = 519.66 g


*** Hypochlorite (chemical) required ***
% available Cl2 in chemical used = 65 %
Hypochlorite required:
- solid form = 799.48 g
- liquid form = 0.8000 litre


*** Dilution of chemical concentration ***
Final diluted solution concentration = 5 %
Volume of diluted solution = 10.4000 litre
Water added = 9.6000 litre




how to size swimming pool heater ?

how to calculate evaporation loss...

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:

a) wind speed = 7 mph.

b) conduction heat loss = 3% of total losses

c) 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



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



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)



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]:




Qrd = radiation heat loss, W

A = area of pool surface, m2

Es = surface emittance.

[Es = 0.96 for water is used in the aPocketPool program.]

Tp = pool temperature, K

Tsky = apparent sky temperature, K


Tsky is estimated using the following equation [ASHRAE 2011]:




Esky = Sky emittance

Tdp = Ambient air dew point temperature, K


Note: For indoor pool, radiation heat loss is ignored in the aPocketPool program.


Conduction Loss

The conduction loss is small and can be ignored in general.


Note: allowance as percentage of total heat losses can be allowed for in the aPocketPool program.



Using the aPocketPool program, the heat losses calculated are presented below:



Heat Loss


 Evaporation374454.7  75.0 
 Convection41943.0 8.4 
 Radiation 67637.413.6 
 Conduction 14970.2 3.0
 Total499005.3   100
Saturation vapour pressure at pool water temp. (in.Hg) = 1.033
Saturation vapour pressure at air dew point temp. (in.Hg) = 0.439
Ambient air dew point (oF) = 55.2
Apparent sky temp. (oF) = 53.9
Convective heat transfer coeff. (btu/h.ft2.oF) = 3.1

Note that the above calculated results are the peak or design heat losses based on the design conditions.





 Calculation Example 4: 

Pool heat-up heating . . .  

If the owner wants to heat-up the pool in Example 3 in 24 hr, what is the pool heat-up heat required?


Before you determine the heat-up heat for the specific pool, the following operating conditions are noted:

a) Pool cover will be used during the initial heat-up period.

b) It is determined in Example 3 that evaporation, convection and radiation losses contribute 97% of the total losses. With pool cover, these losses and other minor losses such as conduction, etc. will be ignored.


The calculated heat-up heat required are presented below:


Pool volume = 80969 USgal
Initial pool water temp. = 65 oF
Desired pool water temp. = 80 oF
Temperature difference = 15.00 oF
Heat-up time = 24 hr
Heat-up rate = 0.62 oF/hr


Heat-up heat (output) = 423657 BTU/h




Need to calculate pipe pressure drop (head loss)?, see


Android's  multiple Pipes Pressure Drop


or Windows' easy Pipe Friction Loop


aPocketPool (Android)

  at Android Market  


OS requirements: Android        



To Purchase & Download to your Android device:




at Android Market


For product enquiry, email me.




in SI and IP Units 

 Pool Filtration Calculation...1 




Pool Filtration Calculation...2



  aPocketPool Menu 



 Pool Area & Volume Calculation 



Pool Shape Selection




Filter Selection 



Hypo Chlorination Calculation...1



Hypo Chlorination Calculation...2





Pool Heat-Up Heat Calculation



Pool Heat Losses Calculation...1




Pool Heat Losses Calculation...2