ASHRAE STD 90.4
Energy Standard for Data Centers
|Publication Date:||30 October 2020|
Addendum a encourages recovery of waste heat from data centers for use in space heating and industrial applications, resulting in net energy savings on a societal level. The addendum also encourage siting of data centers in proximity to heat-consuming commercial and industrial processes (e.g., food production facilities) in order to take advantage of heat transfer, minimize waste, and reduce overall energy use.
Addendum a also improves and clarifies ambiguous and obsolete language in Section 6.5. For example, 6.5 currently says "In the case of cooling provided by a source other than electricity, the energy consumption shall be converted to kilowatt-hours" but does not say how to perform this conversion. This addendum clarifies how to perform the conversion. Currently, Section 6.5 also says to include chiller and AHU fan energy serving a UPS room but does not say to include cooling tower or pump energy serving the UPS room, which was clearly the intent. This addendum clarifies that the energy of all mechanical equipment serving UPS rooms is also included.
The other substantive change to Section 6.5 is removal of language that states in part, "...if the data center utilizes mechanical cooling, the calculated rack inlet temperature and dew point must be within Thermal Guidelines for Data Processing Environments recommended thermal envelope for more than 8460 of the hours per year." Many data centers operate outside the ASHRAE Thermal Guidelines for more than 300 hours per year and do not have the capacity to stay within them for 8460 hours. This addendum allows designers to model their data centers as they are truly intended to operate.
Note: In this addendum, changes to the current standard are indicated in the text by underlining (for additions) and (for deletions) unless the instructions specifically mention some other means of indicating the changes.