scholarly journals Optimization and predictive control of a vapor compression cycle under transient pulse heat load

2017 ◽  
Vol 75 ◽  
pp. 14-25 ◽  
Author(s):  
Zehao Yang ◽  
Daniel T. Pollock ◽  
John T. Wen
Keyword(s):  
Predictive Control ◽  
Heat Load ◽  
Vapor Compression ◽  
Pulse Heat ◽  
Vapor Compression Cycle ◽  
Compression Cycle

Offset-free model predictive control of a vapor compression cycle

2012 ◽  
Vol 22 (7) ◽  
pp. 1374-1386 ◽  
Author(s):  
Matt Wallace ◽  
Buddhadeva Das ◽  
Prashant Mhaskar ◽  
John House ◽  
Tim Salsbury
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
Vapor Compression ◽  
Vapor Compression Cycle ◽  
Compression Cycle ◽  
Free Model

A Model Predictive Control Law for a Vapor Compression Cycle System

2016 ◽  
Author(s):  
Anhtuan D. Ngo ◽  
Joshua R. Cory
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
Thermal Load ◽  
Cooling System ◽  
Thermal System ◽  
Control Input ◽  
Vapor Compression ◽  
Error Performance ◽  
Vapor Compression Cycle ◽  
Compression Cycle

During the development of next generation tactical aircraft, thermal management is given significant consideration due to higher transient cooling demands, with stricter temperature limits along with the smaller size and weight in the cooling system hardware. Traditional control approaches, such as proportional-integral-derivative (PID), are sufficient to achieve the desired steady-state error performance for a thermal system with no constraints on the control inputs. The traditional control techniques may not be well-suited for thermal systems with constrained inputs. In this paper, we apply the Model Predictive Control (MPC) technique on an input-constrained thermal system and examine the system performance under a large transient thermal load and control input limits through the anticipation of the known thermal load. The results include design and implementation of an MPC controller for a high-fidelity, nonlinear vapor compression cycle model, as well as comparison of the MPC results to those of a finely tuned PID controller.

The Steady-State Modeling and Analysis of a Two-Loop Cooling System for High Heat Flux Removal

2009 ◽  
Author(s):  
Rongliang Zhou ◽  
Juan Catano ◽  
Tiejun Zhang ◽  
John T. Wen ◽  
Greg J. Michna ◽  
...  
Keyword(s):  
Heat Flux ◽  
Steady State ◽  
Heat Exchangers ◽  
Cooling System ◽  
High Heat ◽  
System Structure ◽  
High Heat Flux ◽  
Vapor Compression ◽  
Vapor Compression Cycle ◽  
Compression Cycle

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.

Rechargeable Personal Air Conditioning Device

2016 ◽  
Author(s):  
Yilin Du ◽  
Jan Muehlbauer ◽  
Jiazhen Ling ◽  
Vikrant Aute ◽  
Yunho Hwang ◽  
...  
Keyword(s):  
Air Conditioning ◽  
Cooling System ◽  
Cooling Capacity ◽  
Comfort Level ◽  
Vapor Compression ◽  
Air Conditioning System ◽  
System A ◽  
Single Person ◽  
Vapor Compression Cycle ◽  
Compression Cycle

A rechargeable personal air-conditioning (RPAC) device was developed to provide an improved thermal comfort level for individuals in inadequately cooled environments. This device is a battery powered air-conditioning system with the phase change material (PCM) for heat storage. The condenser heat is stored in the PCM during the cooling operation and is discharged while the battery is charged by using the vapor compression cycle as a thermosiphon loop. The conditioned air is discharged towards a single person through adjustable nozzle. The main focus of the current research was on the development of the cooling system. A 100 W cooling capacity prototype was designed, built, and tested. The cooling capacity of the vapor compression cycle measured was 165.6 W. The PCM was recharged in nearly 8 hours under thermosiphon mode. When this device is used in the controlled built environment, the thermostat setting can be increased so that building air conditioning energy can be saved by about 5–10%.

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