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.TT pocketEngineer softDesign

... pocketEngineer software for mobile design

pocketEngineer software  animated gif (free)  email me  buy now  Rethink, Reinvent apps   
...Ductulator Plus+
...aDuctulator (And)
...aBattMV (And)
...aKitchenExhaust (And)
...tRod Sizer (free)
...pocketPipe Sizer
...aPipeSizer (And)
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...rhoAIR (free)
...aRhoAIR (free) (And)
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...AirTAB superEZ
...Qcool Check
...aCriticalVel (And)
...aPocketPool (And)
ePF Loop Pdrop
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...Pumping Mainline
the home of .TT pocketEngineer softDesign - where pocketEngineer software lives...
 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