TY - GEN
T1 - Low-Pressure Heat Transfer Fluids for Pumped Two-Phase Cooling
AU - Karwa, Nitin
AU - Motta, Samuel Yana
N1 - Publisher Copyright:
© 2021 IEEE
PY - 2021
Y1 - 2021
N2 - The increasing heat flux from chips, and high server- and rack-level heat densities in high performance computing infrastructure have resulted in the advent of advanced cooling technologies, such as cold plates and immersion cooling. Water-based heat transfer fluids are used in cold plate systems. It is widely debated if it will be effective and energy efficient for cooling of chips with heat flux exceeding 500 kW/m2. Two-phase cooling with dielectric fluorinated fluids, such as hydrofluorocarbons (HFC), hydrochlorofluoroolefins (HCFO), hydrofluoroolefins (HFO), hydrofluoroethers (HFE), in cold plates may be more suited to sustain the ever-increasing heat density. The need to cool devices with ever-increasing power density, the push towards lower global warming potential fluids, and the occupational and equipment safety requirements has motivated a search for suitable two-phase heat transfer fluids. This paper introduces the environmental and occupational safety aspects, and effect of global regulations on the selection of fluorinated heat transfer fluids for use in data centers. This study presents drop-in performance evaluation of low-pressure fluid options, namely, HCFO-1233zd (E), HFC-245fa and HFE-7000, in pumped two-phase cooling system for heat flux up to 640 kW/m2. Performance is also compared with single-phase water cooling. The performance is reported in terms of thermal resistances of the cold plate and the system. Compared to water cooling, two-phase cooling achieved lower junction temperatures and more uniform cooling at much lower flow rate. System level thermal resistance was lower for two-phase cooling, except with HFE-7000, which had considerably high thermal resistance in the condenser. Unlike HCFO-1233zd(E), HFC-245fa will be eventually phased-down globally, therefore it is not a sustainable long-term option for the industry. This study shows that HCFO-1233zd(E) is a feasible low-pressure heat transfer fluid option for thermal management of high performance computing infrastructure.
AB - The increasing heat flux from chips, and high server- and rack-level heat densities in high performance computing infrastructure have resulted in the advent of advanced cooling technologies, such as cold plates and immersion cooling. Water-based heat transfer fluids are used in cold plate systems. It is widely debated if it will be effective and energy efficient for cooling of chips with heat flux exceeding 500 kW/m2. Two-phase cooling with dielectric fluorinated fluids, such as hydrofluorocarbons (HFC), hydrochlorofluoroolefins (HCFO), hydrofluoroolefins (HFO), hydrofluoroethers (HFE), in cold plates may be more suited to sustain the ever-increasing heat density. The need to cool devices with ever-increasing power density, the push towards lower global warming potential fluids, and the occupational and equipment safety requirements has motivated a search for suitable two-phase heat transfer fluids. This paper introduces the environmental and occupational safety aspects, and effect of global regulations on the selection of fluorinated heat transfer fluids for use in data centers. This study presents drop-in performance evaluation of low-pressure fluid options, namely, HCFO-1233zd (E), HFC-245fa and HFE-7000, in pumped two-phase cooling system for heat flux up to 640 kW/m2. Performance is also compared with single-phase water cooling. The performance is reported in terms of thermal resistances of the cold plate and the system. Compared to water cooling, two-phase cooling achieved lower junction temperatures and more uniform cooling at much lower flow rate. System level thermal resistance was lower for two-phase cooling, except with HFE-7000, which had considerably high thermal resistance in the condenser. Unlike HCFO-1233zd(E), HFC-245fa will be eventually phased-down globally, therefore it is not a sustainable long-term option for the industry. This study shows that HCFO-1233zd(E) is a feasible low-pressure heat transfer fluid option for thermal management of high performance computing infrastructure.
KW - Environmental regulations
KW - HCFO-1233zd(E)
KW - HFC-245fa
KW - HFE-7000
KW - High performance computing
KW - Low-pressure fluid
KW - Microchannel cold plate
KW - Occupational safety
KW - Pumped two-phase cooling
KW - Refrigerant
KW - Thermal resistance
KW - Water
UR - http://www.scopus.com/inward/record.url?scp=85125357292&partnerID=8YFLogxK
U2 - 10.1109/ITherm51669.2021.9503137
DO - 10.1109/ITherm51669.2021.9503137
M3 - Conference contribution
AN - SCOPUS:85125357292
T3 - InterSociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, ITHERM
SP - 188
EP - 196
BT - Proceedings of the 20th InterSociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, ITherm 2021
PB - IEEE Computer Society
T2 - 20th InterSociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, ITherm 2021
Y2 - 1 June 2021 through 4 June 2021
ER -
