Hello, i would like to manually verify DX coil sizing in zonal equipment. The zone coil load should include ventilation and infiltration latent load. But unfortunately E+ standard report doesn't have them in desired format (g/kg instead of W). Update from Mr. Rraustad suggestion and E+ documentation : input as follow : Bases on psychrometric coil sizing formula :

set  standard air density (1,2 kg/ m3)

mixed air flow = User Calc air flow =0.884 m3/s = 0.857(return air flow) +0.027 (outdoor air flow)

Enthalpy outdoor (36oC, 0.02207g/kg) = 92.87 kJ/kg ;Enthalpy return air/room air (26oC, 0.01138 g/kg) = 55.21 kJ/kg

 Enthalpy supply air (14oC, 0.009 g/kg) = 36.87 kJ/kg

 Enthalpy mix = ( Outdoor air enthalpy * Outdoor air flow + Return air flow * Return outdoor enthalpy)/mixed air flow = 56.37 kJ/kg -> air temperature = 26.3 oC air density = 1.157 kg/m3 

   Performance CAPFT : x = mixed air wetbulb = 19.68 oC , y = outdoor drybulb = 36 oC

CapFT= 1.5509 + (-0.07505) * 19.68 + 0.0031 * 19.68^2 + 0.0024 * 36 + (0.00005) * 36^2 + 36 * 19.68 *(-0.00043) = 1.121

Coil capacity =  (Enthalpy mix - Enthalpy sizing zone ) * (air density) *  (airflow) /  (CapFT) 
                    =     (55.21 - 36.87) * 1.157 * 0.884 /1.121 = 17782 W

The coil report for PTAC :

Great Thanks to Mr Rraustad for validation.

Hello, i would like to manually verify DX coil sizing in zonal equipment. The zone coil load should include ventilation and infiltration latent load. But unfortunately E+ standard report doesn't have them in desired format (g/kg instead of W). Update from Mr. Rraustad suggestion and E+ documentation : input as follow : Bases on psychrometric coil sizing formula :

set  standard air density (1,2 kg/ m3)

mixed air flow = User Calc air flow =0.884 m3/s = 0.857(return air flow) +0.027 (outdoor air flow)

Enthalpy outdoor (36oC, 0.02207g/kg) = 92.87 kJ/kg ;Enthalpy return air/room air (26oC, 0.01138 g/kg) = 55.21 kJ/kg

 Enthalpy supply air (14oC, 0.009 g/kg) = 36.87 kJ/kg

 Enthalpy mix = ( Outdoor air enthalpy * Outdoor air flow + Return air flow * Return outdoor enthalpy)/mixed air flow = 56.37 kJ/kg -> air temperature = 26.3 oC air density = 1.157 kg/m3 
56.36 kJ/kg

   Performance CAPFT : x = mixed air wetbulb = 19.68 oC , y = outdoor drybulb = 36 oC

CapFT= 1.5509 + (-0.07505) * 19.68 + 0.0031 * 19.68^2 + 0.0024 * 36 + (0.00005) (-0.00005) * 36^2 + 36 * 19.68 *(-0.00043) = 1.121
0.991579

Coil capacity =  (Enthalpy mix - Enthalpy sizing zone ) * (air density) *  (airflow) /  (CapFT) 
                    =     (55.21 - 36.87) * 1.157 1.2 * 0.884 /1.121 = 17782 W
/0.9916 = 20.85 kW

The coil report for PTAC :

Great Thanks Please help me to Mr Rraustad for validation.clarify this difference. Thanks

Hello, i would like to manually verify DX coil sizing in zonal equipment. The zone coil load should include ventilation and infiltration latent load. But unfortunately E+ standard report doesn't have them in desired format (g/kg instead of W). Update from Mr. Rraustad suggestion and E+ documentation : input as follow : Bases on psychrometric coil sizing formula :

set  standard air density (1,2 kg/ m3)

mixed air flow = User Calc air flow =0.884 m3/s = 0.857(return air flow) +0.027 (outdoor air flow)

Enthalpy outdoor (36oC, 0.02207g/kg) = 92.87 kJ/kg ;Enthalpy return air/room air (26oC, 0.01138 g/kg) = 55.21 kJ/kg

 Enthalpy supply air (14oC, 0.009 g/kg) = 36.87 kJ/kg

 Enthalpy mix = ( Outdoor air enthalpy * Outdoor air flow + Return air flow * Return outdoor enthalpy)/mixed air flow = 56.36 kJ/kg

   Performance CAPFT : x = mixed air wetbulb = 19.68 oC , y = outdoor drybulb = 36 oC

CapFT= 1.5509 + (-0.07505) * 19.68 + 0.0031 * 19.68^2 + 0.0024 * 36 + (-0.00005) * 36^2 + 36 * 19.68 *(-0.00043) = 0.991579

Coil capacity =  (Enthalpy mix - Enthalpy sizing zone ) * (air density) *  (airflow) /  (CapFT)  = 19.99 kW
                    =     (55.21 - 36.87) * 1.2 * 0.884 /0.9916 = 20.85 kW

The coil report for PTAC ::

Please help me to clarify this difference. Thanks

Hello, i would like to manually verify DX coil sizing in zonal equipment. The zone coil load should include ventilation and infiltration latent load. But unfortunately E+ standard report doesn't have them in desired format (g/kg instead of W). Update from Mr. Rraustad suggestion and E+ documentation : input as follow : Bases on psychrometric coil sizing formula :

set  standard air density (1,2 kg/ m3)

mixed air flow = User Calc air flow =0.884 m3/s = 0.857(return air flow) +0.027 (outdoor air flow)

Enthalpy outdoor (36oC, 0.02207g/kg) = 92.87 kJ/kg ;Enthalpy return air/room air (26oC, 0.01138 g/kg) = 55.21 kJ/kg

 Enthalpy supply air (14oC, 0.009 g/kg) = 36.87 kJ/kg

 Enthalpy mix = ( Outdoor air enthalpy * Outdoor air flow + Return air flow * Return outdoor enthalpy)/mixed air flow = 56.36 kJ/kg

   Performance CAPFT : x = mixed air wetbulb = 19.68 oC , y = outdoor drybulb = 36 oC

CapFT= 1.5509 + (-0.07505) * 19.68 + 0.0031 * 19.68^2 + 0.0024 * 36 + (-0.00005) * 36^2 + 36 * 19.68 *(-0.00043) = 0.991579

Coil capacity =  (Enthalpy mix - Enthalpy sizing zone ) * (air density) *  (airflow) /  (CapFT) = 19.99 kW
                    =     (55.21 - 36.87) * 1.2 * 0.884 /0.9916 = 20.85 kW

The coil report for PTAC :

Please help me How i need to clarify do in this difference. Thankscase ?

Hello, i would like to manually verify DX coil sizing in zonal equipment. The zone coil load should include ventilation and infiltration latent load. But unfortunately E+ standard report doesn't have them in desired format (g/kg instead of W). How i need to do in this case ?