Hi,
It is unclear to me how to model plug and process loads for Core and Shell
Projects in Canada. There seems to be a conflict between Appendix 2 and the
Table on Page 292 of the Reference Guide. Has anyone else run into this
before we send in a CIR?
The Appendix wants you to use Table 1 plug load densities (i.e. 1.5W/sq ft
for office buildings) for the tenant spaces while Page 292 says to use
values from the standards (i.e. 0.75W/sq ft for office buildings) or provide
documentation for modelled loads.
It's almost like they want you to use the higher value for tenant spaces to
account for unknown plug and process loads in CS projects (server rooms and
resultant A/C, etc.). If so, I'm not sure if we should still model
elevators, escalators in the common areas or if they are supposed to be
accounted for Table 1.
Any thoughts are appreciated!
Aaron Smith, P.Eng
Hi Aaron,
Is it LEED project? If so, in my opinion, if the process energy accounts for no less than 25% of the total energy consumption, it will be OK.
I used 13W/m2 and 15W/m2 before, both OK to acquire the certificate, and I even do not need to explain how the 13 or 15 W/m2 comes.
The elevator energy is included in the process load, so you do not need to separate it out.
Xing
Hi,
It is unclear to me how to model plug and process loads for Core and Shell Projects in Canada. There seems to be a conflict between Appendix 2 and the Table on Page 292 of the Reference Guide. Has anyone else run into this before we send in a CIR?
The Appendix wants you to use Table 1 plug load densities (i.e. 1.5W/sq ft for office buildings) for the tenant spaces while Page 292 says to use values from the standards (i.e. 0.75W/sq ft for office buildings) or provide documentation for modelled loads.
It?s almost like they want you to use the higher value for tenant spaces to account for unknown plug and process loads in CS projects (server rooms and resultant A/C, etc.). If so, I?m not sure if we should still model elevators, escalators in the common areas or if they are supposed to be accounted for Table 1.
Any thoughts are appreciated!
Aaron Smith,P.Eng
Aaron ?
I?ve seen both approaches used, since both are cited in the reference manual.
In my opinion, some developers may allocate 1.5 W/sf or more to tenants, but if fit out by typical office tenants, something like 0.75 W/sf is closer to the ASHRAE Fundamentals ?light / medium? loads (p18.13 of Fundamentals 2009). Further, the ASHRAE numbers were developed for peak cooling load calculations, not operating averages, so there is likely some additional diversity in operation which should tend to lower these numbers. Also, since I?m often modeling using schedules from ASHRAE?s User Manual, a case could be made that it is better to use ASHRAE?s tenant plug load numbers to be consistent.
Generally, even when I?m using the higher Core and Shell Appendix 2 numbers, I model elevators separately/explicitly, since Appendix 2 calls the numbers ?tenant receptacle loads.?
If you do send in a CIR and get a response, please let me know!
(caveat ? I?m US-based, not sure if there are variances due to Canada-specific research / codes.)
Aaron Dahlstrom , PE, LEED? AP
Aaron, thanks for bringing it to my attention that the USGBC has the same
table in Appendix 2. The difference in the Canadian version of CS is that
there is no requirement for Process energy to be 25% of the baseline energy
cost. In my case total process and plug loads are currently at 24% of the
design building but only 10% of the Baseline building.
I??ll let you know if we send in a CIR but I think the 25% requirement would
override everything for your and as you say it might not hold up with the
USGBC anyways.
Aaron Smith, P.Eng