On Sat, May 6, 2017 at 2:12 PM, Javed Iqbal eee.javed@xxxxxxxxx [EnergyPlus_Support] <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:
Dear All,We are investigating zone cooling load peak component summary for analyzing load contribution from all the internal and external sources (refer following table). We are struggling to answer few questions which are as follows:
- We referred engineering manual and I/O guide to understand the sensible delayed column. We found delayed effect contribution is significant, sometime its higher than sensible instant. We are unable to clearly understand how this delayed effect could contribute so high compared to instant gain? what is the basis of this delayed calculations?
- The reported value of sensible delayed could be minimize to zero if Radiative heat fraction defined for people, lights and equipment are reduced to zero in IDF. Hence, Radiative heat fraction effects sensible delayed effect significantly. Are there any industry standard to use optimum Radiative heat fraction for the people, lights and equipment?Â
- If the building is highly insulated, the sensible delayed for people, lights and equipment are reported with (-ve sign convention). In the following table the external and interzone wall showing gains with -ve sign. What does -ve sign indicates in sensible delayed column? How to interpret this correctly?
Estimated Cooling Peak Load Components
Sensible - Instant [W] Sensible - Delayed [W] Sensible - Return Air [W] Latent [W] Total [W] %Grand Total People 4396.35 6572.28  4711.68 15680.31 37.55 Lights 869.22 3686.38 0.00  4555.59 10.91 Equipment 13153.03 11493.52  0.00 24646.55 59.01 Refrigeration 0.00  0.00 0.00 0.00 0.00 Water Use Equipment 0.00   0.00 0.00 0.00 HVAC Equipment Losses 0.00 0.00   0.00 0.00 Power Generation Equipment 0.00 0.00   0.00 0.00 Infiltration 863.78   974.58 1838.37 4.40 Zone Ventilation 0.00   0.00 0.00 0.00 Interzone Mixing 0.00   0.00 0.00 0.00 Roof  25.86   25.86 0.06 Interzone Ceiling  0.00   0.00 0.00 Other Roof  0.00   0.00 0.00 Exterior Wall  -4824.8   -4824.8 -11.6 Interzone Wall  -2594.2   -2594.2 -6.2 Ground Contact Wall  0.00   0.00 0.00 Other Wall  0.00   0.00 0.00 Exterior Floor  -580.3   -580.3 -1.4 Interzone Floor  0.00   0.00 0.00 Ground Contact Floor  0.00   0.00 0.00 Other Floor  0.00   0.00 0.00 Fenestration Conduction 1790.84    1790.84 4.29 Fenestration Solar  1225.17   1225.17 2.93 Opaque Door  0.00   0.00 0.00 Grand Total 21073.22 15003.94 0.00 5686.27 41763.43 â??We would appreciate any help on this.Thanks, â??--Javed Iqbal, LEED AP, CEASr. Energy AnalystÂ--James V Dirkes II, PE, BEMP, LEED AP
CEO/President
The Building Performance Team Inc.
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Posted by: Jim Dirkes <jim@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
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