Data Centers Efficiency Improvements

Measure Overview

This proposal seeks to address data center/computer room code requirements in sections 100.1, 120.6(j)3 (mandatory), 140.9(a) (prescriptive), 141.1(b)1 of T24 Part 6 by including the following measures:  

Measure 1: Computer Room Economizers (Update Existing Sections 100.1, 140.9(a)1, 141.1(b)1)   

This measure would expand definitions related to computer rooms and data centers, such as adding Liquid-cooled Information Technology Equipment (ITE), facility water, and expanding guidance on ways to ensure computer room economizers are fully integrated. Additionally, this proposed change would expand the number of hours economizers must meet all or part of the computer room cooling load in newly constructed computer rooms and existing computer room additions and alterations by adjusting the 100 percent wet-bulb economizer threshold for air-cooled ITE, adding new economizer thresholds for >2MW liquid-cooled ITE loads, and imposing minimum water and air temperature differentials and variable flow requirements to ensure integrated economizer savings. 

To create additional flexibility in complying with the proposed requirements, new exceptions would be added for new computer rooms using a heat recovery system meeting specified minimum capacity thresholds, and existing computer rooms being able to comply with the Title 24, Part 6 economizer requirements that were in effect when the building was permitted, when undergoing an addition or alteration.  

Measure 2: Fan Control Requirements (Update Existing Section 120.6(j)3)  

This measure proposes to modify mandatory requirements in section 120.6(j)3 by reducing the unitary air conditioner capacity threshold for when variable supply airflow is required in new and existing computer rooms. This would result in a greater number of unitary air conditioners for computer rooms being installed with variable speed supply fans that modulate airflow based on cooling load. The threshold for when variable airflow fan control is required would be reduced from a 60,000 Btu/hr unit to a 30,000 Btu/hr unit.  

Measure 3: Computer Room Heat Recovery (New Section 140.9(a)5)  

This proposed measure would add prescriptive requirements to Section 140.9 to require new nonresidential buildings with both a computer room(s) and sizable heating loads to recover heat from the computer room(s) to serve other building heating loads. Computer room heat recovery is being defined as a mechanical system that transfers heat from a computer room(s) to provide heating to other zones or end-uses in the building that require heating. Heat recovery would be required in new buildings with computer rooms if the following conditions were met:  

• Buildings with a design computer room(s) ITE load greater than 100 kW; and 
• Buildings with non-computer room directly conditioned floor area greater than 35,000 ft2.

The required capacity of the heat recovery system would depend on the peak cooling capacity of the computer room and the combined total peak heating capacity of the space heating system and service water heating (i.e., domestic hot water) system. The heat recovery system’s heat recovery capacity must be the lesser of the two values: 

• 0.25 times the peak heat rejection capacity of the computer room system 
• 0.25 times (the total capacity of the space heating system plus the SWH system)

Table 1 summarizes the scope of the proposed code change across all measures.