The steady-state modeling and analysis of a two-loop cooling system for high heat flux removal

Rongliang Zhou, Juan Catano, Tiejun Zhang, John T. Wen, Greg J. Michna, Yoav Pelest, Michael K. Jensent

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

1 Scopus citations


Steady-state modeling and analysis of a two-loop cooling system for high heat flux removal applications are studied. The system structure proposed consists of a primary pumped loop and a vapor compression cycle (VCC) as the secondary loop to which the pumped loop rejects heat. The pumped loop consists of evaporator, condenser, pump, and bladder liquid accumulator. The pumped loop evaporator has direct contact with the heat generating device and CHF must be higher than the imposed heat fluxes to prevent device burnout. The bladder liquid accumulator adjusts the pumped loop pressure level and, hence, the subcooling of the refrigerant to avoid pump cavitation and to achieve high critical heat flux (CHF) in the pumped loop evaporator. The vapor compression cycle of the two-loop cooling system consists of evaporator, liquid accumulator, compressor, condenser and electronic expansion valve. It is coupled with the pumped loop through a fluid-to-fluid heat exchanger that serves as both the vapor compression cycle evaporator and the pumped loop condenser. The liquid accumulator of the vapor compression cycle regulates the cycle active refrigerant charge and provides saturated vapor to the compressor at steady state. The heat exchangers are modeled with the mass, momentum, and energy balance equations. Due to the projected incorporation of microchannels in the pumped loop to enhance the heat transfer in heat sinks, the momentum equation, rarely seen in previous refrigeration system modeling efforts, is included to capture the expected significant microchannel pressure drop wit nessed in previous experimental investigations. Electronic expansion valve, compressor, pump, and liquid accumulators are modeled as static components due to their much faster dynamics compared with heat exchangers. The steady-state model can be used for static system design that includes determining the total refrigerant charge in the vapor compression cycle and the pumped loop to accommodate the varying heat load, sizing of various components, and parametric studies to optimize the operating conditions for a given heat load. The effect of pumped loop pressure level, heat exchangers geometries, pumped loop refrigerant selection, and placement of the pump (upstream or downstream of the evaporator) are studied. The two-loop cooling system structure shows both improved coefficient of performance (COP) and CHF over the single loop vapor compression cycle investigated earlier by authors for high heat flux removal.

Original languageBritish English
Title of host publicationProceedings of the ASME International Mechanical Engineering Congress and Exposition 2009, IMECE 2009
Number of pages12
EditionPART B
StatePublished - 2010
EventASME 2009 International Mechanical Engineering Congress and Exposition, IMECE2009 - Lake Buena Vista, FL, United States
Duration: 13 Nov 200919 Nov 2009

Publication series

NameASME International Mechanical Engineering Congress and Exposition, Proceedings
NumberPART B


ConferenceASME 2009 International Mechanical Engineering Congress and Exposition, IMECE2009
Country/TerritoryUnited States
CityLake Buena Vista, FL


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