Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
The inclusion of fan heat in coil sizing does not affect the coil output during the simulation (which has always included zone load, fan heat and outdoor air load). This change, the inclusion of fan heat in cooling coil sizing, only affects the calculation of coil size. You say the difference is only 2-20 W while the fan heat gain is 20-120 W. Can you check the zone loads reported in the eio and see if those still match. You could also use V9.0 and test how fan heat affects coil sizing by setting the Design Pressure Rise to near 0 and compare with what you have now.
| | 2 | No.2 Revision |
The inclusion of fan heat in coil sizing does not affect the coil output during the simulation (which has always included zone load, fan heat and outdoor air load). This change, the inclusion of fan heat in cooling coil sizing, only affects the calculation of coil size. You say the difference is only 2-20 W while the fan heat gain is 20-120 W. Can you check the zone loads reported in the eio and see if those still match. You could also use V9.0 and test how fan heat affects coil sizing by setting the Design Pressure Rise to near 0 and compare with what you have now.
PeakCoilLoad = rhoair * DesVolFlow * (CoilInEnth - CoilOutEnth) + DesignFanHeat
| | 3 | No.3 Revision |
The inclusion of fan heat in coil sizing does not affect the coil output during the simulation (which has always included zone load, fan heat and outdoor air load). This change, the inclusion of fan heat in cooling coil sizing, only affects the calculation of coil size. You say the difference is only 2-20 W while the fan heat gain is 20-120 W. Can you check the zone loads reported in the eio and see if those still match. You could also use V9.0 and test how fan heat affects coil sizing by setting the fan's Design Pressure Rise to near 0 and compare with what you have now.
PeakCoilLoad = rhoair * DesVolFlow * (CoilInEnth - CoilOutEnth) + DesignFanHeat
| | 4 | No.4 Revision |
The inclusion of fan heat in coil sizing does not affect the coil output during the simulation (which has always included zone load, fan heat and outdoor air load). This change, the inclusion of fan heat in cooling coil sizing, only affects the calculation of coil size. You say the difference is only 2-20 W while the fan heat gain is 20-120 W. Can you check the zone loads reported in the eio and see if those still match. You could also use V9.0 and test how fan heat affects coil sizing by setting the fan's Design Pressure Rise to near 0 and compare with what you have now.
DesFanHeat = MotEff * FanPowerTot + (FanPowerTot - MotEff * FanPowerTot) * MotInAirFrac
PeakCoilLoad = rhoair * DesVolFlow * (CoilInEnth - CoilOutEnth) + DesignFanHeat
DesFanHeat
| | 5 | No.5 Revision |
The inclusion of fan heat in coil sizing does not affect the coil output during the simulation (which has always included zone load, fan heat and outdoor air load). This change, the inclusion of fan heat in cooling coil sizing, only affects the calculation of coil size. You say the difference is only 2-20 W while the fan heat gain is 20-120 W. Can you check the zone loads reported in the eio and see if those still match. You could also use V9.0 and test how fan heat affects coil sizing by setting the fan's Design Pressure Rise to near 0 and compare with what you have now.
FanPowerTot = (FanVolFlow * DeltaP) / TotEff
DesFanHeat = MotEff * FanPowerTot + (FanPowerTot - MotEff * FanPowerTot) * MotInAirFrac
PeakCoilLoad = rhoair * DesVolFlow * (CoilInEnth - CoilOutEnth) + DesFanHeat
