Hi every one, Marcus

I am doing data center energy modeling for LEED V4.

The data center is composed of 3 type spaces.

Usage : dedicated data center

Number of floors : 3

Total gross area : 31,291 ㎡ ( conditioned : 14,160 ㎡ + Unconditioned : 16,681 ㎡)

Conditioned Area(14,160 ㎡)

a) Server Rack room : 8,247 ㎡

b) Electrical/Mechanical for sever room : 5,464 ㎡

c) Other Manage & control room : 449 ㎡

I have some question about selecting the baseline HVAC system for data center.

1) area standard for Baseline system selection

I wonder if the criteria for determining the baseline system is gross floor area or Conditioned floor area. In Appendix G 3.1.1, baseline system shall be based on usage, number of floors, conditioned floor area and heating source. In this case,

2) predominant condition for baseline selection

The predominant condition of data center is Server room. It is different from typical office building. I am confused at this point. Please check out the alternatives I think of.

Alt A : System 8 + G3.1.1 exception b

Nonresidential and More than 5 Floors or > 14,000 ㎡

(conditioned Total gross area : 14,160 ㎡)

or

Alt B : System 6 + G3.1.1 exception b

5 Floors or Less and 2300 ㎡ to 14,000 ㎡

(Predominant condition – Server room : 8,247 ㎡)

3) Only cooling system

In data center, The most spaces of data center(i.g Server room, Electrical room) was conditioned as only cooling(no heating system). Appendix G Table G 3.1.10 indicate that “ ~ system characteristics shall be identical to the system modeled in the baseline building design”. I saw some answers on this forum to solve this problem. some answer say to set the temperature in the space so that the system never comes on. I am using the trace 700 for data center modeling. In Trace 700, Thermostat setting for heating is allowed –17℃. So in this case, can I input “0” at the heating coli capacity of both systems? I understand that the Table G 3.1.10 c not allow the savings for heating. I want to know differece between “the system never comes on” and “coil capacity zero”.