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 Hello! Condensation (Android) 
- a module in aDuctulator 

quick design calculations for surface condensation occurrence, U-value, R-value, heat gain . . .



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



Go to a Ductulator (Android) - HVAC Duct Sizer:

 aDuctulator > > >




 Hello! Condensation 

. . . every now and then, everywhere!







Principle 1: Heat flows from hot to cold.


Principle 2: Surface condensation will occur on the outer surface (hot side) when the outer surface temperature (Ts) falls below or equals the dewpoint temperature (Tdp) of the ambient air.


Principle 3: Add insulation materials (R1+R2+ ... ) to prevent condensation occurrence.


The Hello! Condensation app provides you with the greatest flexibility in predicting surface condensation occurrence. You build (add or delete) the material layers as required, and there is no limitation for the number of layers that can be created.


Predicting surface condensation occurrence involves dewpoint temperature and surface temperature calculations. This is best handled by the computer with just a few clicks.



The following design calculations are done with Hello! Condensation.  





Worked Example 1 - Façade Glazing for viewing gallery (in SI units)


An air-conditioned viewing gallery has a single glazed glass façade to achieve an optimal panoramic view experience. Evaluate its risks of moisture condensation on the exterior surface of the glazed fenestration.


Design and analysis parameters as follows:

Humid / Rainy day outdoor conditions: 26 °C DB, 95 % RH

Sunny day outdoor conditions: 32 °C DB, 55 % RH

Room design conditions: 22 °C DB




 Humid/Rainy day Sunny day
Outside air drybulb temp., To (°C)  2632
Outside air RH (%) 9555
Outside air film resistance, Ro (m².K/W)0.044
Layer 1=  Glass, single glaze
... t= 6.0,  K= 1.05,  R= 0.006
Inside air film resistance, Ri (m².K/W) 0.12
Inside air drybulb temp., Ti (°C)22
Hello! CondensationYESNo
Outer surface temp., Ts (°C)24.9629.41
Outside air dewpoint temp., Tdp (°C) 25.1321.84
Temp. difference, Ts-Tdp (°C)-0.16947.5748
Overall R-value (m².K/W) 0.1700 
Overall U-value (W/m².K)5.8824 
Heat gain (W/m²)23.5358.82
[Units: t(mm),  K(W/m.K),  R(m2.K/W) ]
Concluding Remarks:
Humid / rainy day raises outdoor dewpoint temperature, resulting in a risk of condensation potentially. Anti-condensation system may be necessary for condensation control if occasional condensation occurrence is unacceptable.




Worked Example 2 - Air Conditioning Duct (in IP units)


Is 0.5 inch of insulation thickness adequate?


Design and analysis parameters as follows:

[1] Outside duct environment: 80 °F DB, 95 % RH

[3] Inside duct temperature: 55 °F DB

[4] Duct insulation material: Fibreglass (K=0.236

[4] Insulation thickness: 0.5 inch

[2] Outside surface airfilm (bright, reflective surface): 0.994 hr.ft².F/Btu

[2] Inside surface airfilm (moving air, 3.4 m/s): 0.250 hr.ft².F/Btu


The following presents the results print-out.


=== Condensation Calculations ===

Outside air drybulb temp., To (°F) = 80
Outside air RH (%) = 95
Outside air film resistance, Ro (hr.ft².F/Btu) = 0.994

[Units: t(in),  K(,  R(hr.ft2.F/Btu) ]
Layer 1=  Fibreglass, 32 kg/m3
... t= 0.5,  K= 0.236,  R= 2.119

Inside air film resistance, Ri (hr.ft².F/Btu) = 0.250
Inside air drybulb temp., Ti (°F) = 55


Hello! Condensation = YES
Outer surface temp., Ts (°F) = 72.61
Outside air dewpoint temp., Tdp (°F) = 78.43
Temp. difference, Ts-Tdp (°F) = -5.8191
Overall R-value (hr.ft².F/Btu) = 3.3630
Overall U-value (Btu/hr.ft².F) = 0.2974
Heat gain (Btu/hr.ft²) = 7.43


Concluding Remarks:
If the outside duct conditions is 80 °F DB, 55 % RH (say, normal conditions), 0.5 inch of insulation thickness would be sufficient for condensation control purpose. However, when the outside duct environment hits 80% RH (say, humid rainy conditions), condensation starts to occur. see results printed in pdf format at this condition.
It is important not to calculate the insulation thickness based on the normal condition, but the highest possible or anticipated relative humidity of the ambient air where the duct is installed.


For Duct and Pipe insulation thickness calculation, refer to pockeINSUL (Windows program).





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OS requirements: Android        



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Hello! Condensation inputs



Hello! Condensation results 



 Hello! Condensation material input/edit and R-value calculation





 Hello! Condensation material selection lists




Hello! Condensation surface airfilm selection list 




 Hello! Condensation build material layers (as many as you want)



Hello! Condensation detail material properties (when you click the material textbox)