Two-phase jet impingement heat sink integrated with a compact vapor compression system for electronics cooling

Author(s):  
Pablo A. de Oliveira ◽  
Jader R. Barbosa
2017 ◽  
Vol 139 (3) ◽  
Author(s):  
Pablo A. de Oliveira ◽  
Jader R. Barbosa

The performance of a novel impinging two-phase jet heat sink operating with single and multiple jets is presented and the influence of the following parameters is quantified: (i) thermal load applied on the heat sink and (ii) geometrical arrangement of the orifices (jets). The heat sink is part of a vapor compression cooling system equipped with an R-134a small-scale oil-free linear motor compressor. The evaporator and the expansion device are integrated into a single cooling unit. The expansion device can be a single orifice or an array of orifices responsible for the generation of two-phase jet(s) impinging on a surface where a concentrated heat load is applied. The analysis is based on the thermodynamic performance and steady-state heat transfer parameters associated with the impinging jet(s) for single and multiple orifice tests. The two-phase jet heat sink was capable of dissipating cooling loads of up to 160 W and 200 W from a 6.36 cm2 surface for single and multiple orifice configurations, respectively. For these cases, the temperature of the impingement surface was kept below 40 °C and the average heat transfer coefficient reached values between 14,000 and 16,000 W/(m2 K).


2001 ◽  
Author(s):  
G. Hetsroni ◽  
A. Mosyak ◽  
Z. Segal

Abstract Experimental investigation of a heat sink for electronics cooling is performed. The objective is to keep the operating temperature at a relatively low level of about 323–333K, while reducing the undesired temperature variation in both the streamwise and transverse directions. The experimental study is based on systematic temperature, flow and pressure measurements, infrared radiometry and high-speed digital video imaging. The heat sink has parallel triangular microchannels with a base of 250μm. According to the objectives of the present study, Vertrel XF is chosen as the working fluid. Experiments on flow boiling of Vertrel XF in the microchannel heat sink are performed to study the effect of mass velocity and vapor quality on the heat transfer, as well as to compare the two-phase results to a single-phase water flow.


Author(s):  
Vikas Kumar ◽  
Gulshan Sachdeva ◽  
Sandeep Tiwari ◽  
Parinam Anuradha ◽  
Vaibhav Jain

A conventional vapor compression refrigeration system (VCRS) cascaded with a heat-assisted ejector refrigeration system (ERS) has been experimentally analyzed. Cascading allows the VCRS to operate at lower condenser temperatures and thus achieve a higher coefficient of performance. In this cascaded system, the condenser of the vapor compression system does not dissipate its heat directly to the evaporator of the ERS; instead, water circulates between the condenser of VCRS and the evaporator of ERS to exchange the heat. Seven ejectors of different geometries have been used in the ERS; however, all the ejectors could not maintain thermal equilibrium at the desired operating conditions. The compressor of the cascaded VCRS consumed 1.3 times less power than the noncascaded VCRS. Furthermore, the cascaded system provided a maximum 87.74% improvement in COP over the noncascaded system for the same operating conditions. The performance of the system remained constant until the critical condenser pressure of the ERS.


2021 ◽  
Vol 122 ◽  
pp. 97-109
Author(s):  
Yudong Xia ◽  
Qiang Ding ◽  
Nijie Jing ◽  
Aipeng Jiang ◽  
Xuejun Zhang ◽  
...  

2019 ◽  
Vol 27 (03) ◽  
pp. 1950029
Author(s):  
Vikas Kumar ◽  
Gulshan Sachdeva

The performance of an ejector as an expansion device rather than the conventional expansion valve or capillary tube in a vapor compression system is experimentally analyzed. Experiments have been conducted using 28 ejectors of different dimensions at the same condenser and evaporator temperatures, and it has been observed that for utmost performance, an optimum area ratio of the ejector is required. One of the ejector geometry has been experimented further for a wide range of condenser and evaporator temperatures. The coefficient of performance is found to be enhanced by at least 10% in comparison to the conventional vapor compression system for the considered range of condenser and evaporator temperatures and the maximum improvement in COP obtained is 12.83% at 14.3∘C evaporator temperature and 32.4∘C condenser temperature with 17.9211 ejector area ratio. The refrigerant R134a has been used as the working substance.


2011 ◽  
Vol 110-116 ◽  
pp. 2163-2169
Author(s):  
S. Khosravi ◽  
Yat Huang Yau ◽  
T.M.I. Mahlia ◽  
M.H. Saidi

In the recent researches HVAC with a based desiccant dehumidifier with a low ambient impact is more efficient in comparison to the traditional systems. Hybrid desiccant cooling systems can be used to control indoor air quality in buildings. This paper presents an integrated energy, entropy and exergy analysis of a hybrid desiccant cooling system compare to a compression system based on first and second laws of thermodynamic. The main objective is the use of a method called exergy costing applied to a conventional compression system that has been chosen to provide the proper conditioned air for a building in hot and humid condition. By applying the same method for the equivalent hybrid cooling system and finding the same exergy costing parameters, two systems can be in comparison to find the more economical system. The result illustrated hybrid desiccant cooling system can be providing 19.78% energy saving and 14.5% cheaper than the compression system the same capacity and lifetime. Nomenclature:


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