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Technical
STRATEGIES FOR IECC 2021 COMPLIANCE IN HOT CLIMATES WITH AIR-COOLED CHILLERS
Compiled by Eamonn Ryan based on an ASHRAE Hot Air podcast
In a recent episode of the ASHRAE Hot Air podcast , sponsored by Addison , Hamed Yassagh , an energy engineer at OB Associates and associate member of ASHRAE , provided insights into navigating compliance with the International Energy Conservation Code ( IECC ) 2021 in hot climates using air-cooled chillers .
With a background in mechanical engineering and a PhD in architectural engineering , Yassagh periodically writes columns for ASHRAE Journal . In this instance , Yassagh sheds light on key considerations for data centre designers .
Yassagh emphasises that IECC 2021 directly references ASHRAE Standard 90.4 , marking a significant departure from previous indirect references . This shift poses challenges as compliance becomes more stringent , particularly with the adoption of the Mechanical Load Component ( MLC ) table . Notably , IECC 2021 values for the MLC are approximately half of those in Standard 90.4 , complicating compliance efforts for data centre designers .
Many locals are imposing restrictions on water usage , impacting the feasibility of evaporative cooling solutions . Consequently , air-cooled refrigeration , such as air-cooled chillers , emerges as an alternative . However , typical air-cooled chillers are less efficient than their water-cooled counterparts , posing additional challenges for compliance with energy codes .
Yassagh and his team analyse five scenarios to assess compliance with IECC 2021 in hot , dry climates like Phoenix , Arizona . These scenarios range from baseline air-cooled chiller systems to configurations incorporating integrated economisers and airside pre-cooling . The findings reveal that while some
“ Yassagh notes the importance of adopting an expected approach in data centre design to strike a balance between energy efficiency and reliability .” configurations meet compliance requirements , challenges persist , particularly with the MLC table .
Through their analysis , Yassagh explores the efficacy of airside pre-cooling in enhancing compliance with IECC 2021 . By leveraging the X Factor reliability approach outlined in ASHRAE ' s thermal guidelines for data processing environments , he demonstrates how lower minimum supply temperatures can improve server efficiency without compromising energy consumption .
UNDERSTANDING THE X FACTOR : BALANCING RELIABILITY AND ENERGY EFFICIENCY The X Factor serves as a metric for gauging the relative expected server failure rate at varying server inlet temperatures . With server failure rates being paramount in data centre operations , the X Factor becomes a crucial indicator . A factor of one corresponds to a server inlet temperature of 20 ° C . Higher inlet temperatures result in higher X Factors , indicating greater reliability , while lower temperatures correspond to lower X Factors and higher reliability .
Yassagh notes the importance of adopting an expected approach in data centre design to strike a balance between energy efficiency and reliability . While improving server reliability may sometimes lead to a reduction in energy efficiency , the referenced article underscores instances where enhanced reliability can be achieved without compromising energy efficiency – a valuable opportunity for data centre operators .
CONSIDERATIONS IN AIR-COOLED DATA CENTRE DESIGN Moving beyond energy efficiency and reliability , Yassagh discusses additional considerations essential in air-cooled data centre design . These include :
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RACA Journal I July 2024 www . refrigerationandaircon . co . za