Model Predictive Control of a Pumped Two-Phase Cooling System With Microchannel Heat Exchangers

Author(s):  
Oyuna Angatkina ◽  
Andrew Alleyne

Two-phase cooling systems provide a viable technology for high–heat flux rejection in electronic systems. They provide high cooling capacity and uniform surface temperature. However, a major restriction of their application is the critical heat flux condition (CHF). This work presents model predictive control (MPC) design for CHF avoidance in two-phase pump driven cooling systems. The system under study includes multiple microchannel heat exchangers in series. The MPC controller performance is compared to the performance of a baseline PI controller. Simulation results show that while both controllers are able to maintain the two-phase cooling system below CHF, MPC has significant reduction in power consumption compared to the baseline controller.

2019 ◽  
Vol 163 ◽  
pp. 114338 ◽  
Author(s):  
Fengze Hou ◽  
Wenbo Wang ◽  
Hengyun Zhang ◽  
Cheng Chen ◽  
Chuan Chen ◽  
...  

Author(s):  
Rongliang Zhou ◽  
Juan Catano ◽  
Tiejun Zhang ◽  
John T. Wen ◽  
Greg J. Michna ◽  
...  

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 witnessed 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 overthe single loop vapor compression cycle investigated earlier by authors for high heat flux removal.


2008 ◽  
Vol 31 (3) ◽  
pp. 691-701 ◽  
Author(s):  
B. Agostini ◽  
J.R. Thome ◽  
M. Fabbri ◽  
B. Michel

2015 ◽  
Vol 3 (4) ◽  
pp. 369-391 ◽  
Author(s):  
Nicolas Lamaison ◽  
Jackson Braz Marcinichen ◽  
S. Szczukiewicz ◽  
John R. Thome ◽  
P. Beucher

Author(s):  
Farhad Saffaraval ◽  
Amir Jokar

The objective of this study is to experimentally explore thermodynamic performance of R245fa, as a low-pressure and environmentally-friendly refrigerant, in a microchannel heat exchanger. This heat exchanger is used in an electronics cooling application with high-power density. Due to the large amount of latent heat that is released during evaporation process, the two-phase microchannel coolers are able to remove much more energy compared to single-phase cooling systems. In this study, R245fa is used as the working fluid in a refrigeration pump loop that mainly includes an evaporator, a condenser, a refrigerant pump, and a pressure regulator valve. The goal is to obtain optimal mass flow rates and system pressures while the temperatures in evaporator and condenser are kept constant for specific conditions. The results obtained from this study are then compared to the results previously obtained for water as the working fluid in a similar cooling system. It is expected the evaporative cooling through the microchannel heat exchanger be a viable and effective solution, especially for higher heat flux applications.


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