 | 1 | initial version |
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 ?
| | 2 | retagged |
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 ?
| | 3 | No.3 Revision |
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 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 do in clarify this case ?difference.
Thanks
| | 4 | No.4 Revision |
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
| | 5 | No.5 Revision |
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
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) (0.00005) * 36^2 + 36 * 19.68 *(-0.00043) = 0.991579
1.121
Coil capacity = (Enthalpy mix - Enthalpy sizing zone ) * (air density) * (airflow) / (CapFT)
= (55.21 - 36.87) * 1.2 1.157 * 0.884 /0.9916 = 20.85 kW
/1.121 = 17782 W
The coil report for PTAC :
Please help me Great Thanks to clarify this difference.
ThanksMr Rraustad for validation.
| | 6 | retagged |
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.
