Investigation of the component exergy efficiencies of a two stage vapour compression cycle

Introduction: The ability of laypersons to perform BLS/AED increases immediately after resuscitation training. Studies indicate that resuscitation skills rapidly decay after initial training, however it is unknown whether teaching technique influence retention of skill. Aim: To study the retention of BLS/AED skills three months after training when teaching laypersons using a four-stage and two-stage teaching technique. Methods: Laypersons (exclusion: health care professionals/students) were randomized to a standardized ERC BLS/AED courses using the four-stage teaching technique or to courses with the same content but modified to a two-stage teaching technique. Participants were tested in a simulated cardiac arrest scenario three months (±five days) after their course to assess retention of BLS/AED. Tests were video recorded and reviewed by two independent assessors blinded to training technique. Skills were assessed using the ERC BLS/AED assessment form. The primary endpoint was passing the test (17 out of 17 skills adequately performed). Results: A total of 160 participants were included in the study. No difference was found in pass rate immediately after training (diff. -1.6%; 95%CI -17.9%; 14.6%). There was no statistical difference in retention of BLS/AED skills (pass rate: both 11%, diff. -0.4%; 95%CI -28%-27%) three months after training . Total average skills adequately performed (of 17) were 13.7 versus 13.3 among laypersons trained with the four-stage (n=64) and the two-stage technique (n=64). No difference was found in number of chest compressions delivered per compression cycle (29±2.8 vs 30±3.1), chest compression rate (107±17 vs 108±19 minute-1), chest compression depth (46±11 vs 43±12 mm), number of effective rescue breaths between compression cycles (1.6±0.7 vs 1.6±0.5) and tidal volume (0.6±0.4 0.7±0.4 L). Conclusion: We found no difference in retention of BLS/AED skills among laypersons taught using a four-stage teaching technique compared to a two-stage teaching technique.

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Exergy analysis of vapour compression-absorption two-stage refrigeration cycle

International Journal of Exergy ◽

10.1504/ijex.2021.115648 ◽

2021 ◽

Vol 35 (2) ◽

pp. 210

Author(s):

Ilhan Tekin Ozturk ◽

Canan Cimsit

Keyword(s):

Exergy Analysis ◽

Refrigeration Cycle ◽

Two Stage ◽

Vapour Compression

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A Waste Heat-Driven Cooling System Based on Combined Organic Rankine and Vapour Compression Refrigeration Cycles

Applied Sciences ◽

10.3390/app9204242 ◽

2019 ◽

Vol 9 (20) ◽

pp. 4242 ◽

Cited By ~ 2

Author(s):

Youcai Liang ◽

Zhibin Yu ◽

Wenguang Li

Keyword(s):

Power Plant ◽

Internal Combustion Engines ◽

Waste Heat ◽

Cooling System ◽

Organic Rankine Cycle ◽

Rankine Cycle ◽

Internal Combustion ◽

Combustion Engines ◽

Compression Cycle ◽

Vapour Compression

In this paper, a heat driven cooling system that essentially integrated an organic Rankine cycle power plant with a vapour compression cycle refrigerator was investigated, aiming to provide an alternative to absorption refrigeration systems. The organic Rankine cycle (ORC) subsystem recovered energy from the exhaust gases of internal combustion engines to produce mechanical power. Through a transmission unit, the produced mechanical power was directly used to drive the compressor of the vapour compression cycle system to produce a refrigeration effect. Unlike the bulky vapour absorption cooling system, both the ORC power plant and vapour compression refrigerator could be scaled down to a few kilowatts, opening the possibility for developing a small-scale waste heat-driven cooling system that can be widely applied for waste heat recovery from large internal combustion engines of refrigerated ships, lorries, and trains. In this paper, a model was firstly established to simulate the proposed concept, on the basis of which it was optimized to identify the optimum operation condition. The results showed that the proposed concept is very promising for the development of heat-driven cooling systems for recovering waste heat from internal combustion engines’ exhaust gas.

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Thermodynamic Analysis of a Two Stage Vapour Compression Refrigeration System Utilizing the Waste Heat of the Intercooler for Water Heating

Journal of Fundamentals of Renewable Energy and Applications ◽

10.4172/2090-4541.1000232 ◽

2017 ◽

Vol 07 (04) ◽

Cited By ~ 1

Author(s):

Aftab Anjum ◽

Mohit Gupta ◽

Naushad A Ansari ◽

Mishra RS

Keyword(s):

Thermodynamic Analysis ◽

Waste Heat ◽

Refrigeration System ◽

Water Heating ◽

Two Stage ◽

Vapour Compression

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CFD-Simulation Assisted Design of Elastocaloric Regenerator Geometry

Sustainability ◽

10.3390/su12219013 ◽

2020 ◽

Vol 12 (21) ◽

pp. 9013

Author(s):

Kristina Navickaitė ◽

Michael Penzel ◽

Christian Bahl ◽

Kurt Engelbrecht ◽

Jaka Tušek ◽

...

Keyword(s):

Flat Plate ◽

World Wide ◽

Cfd Simulation ◽

Volume Ratio ◽

Cooling Power ◽

Promising Alternative ◽

Compression Cycle ◽

Elastocaloric Cooling ◽

Conventional Cooling ◽

Vapour Compression

Elastocaloric cooling is a promising alternative to conventional cooling using the vapour compression cycle, with potentially higher theoretical exergy efficiency. Nevertheless, there is a number of challenges to be tackled before the technology can be commercially available world-wide. In this study, the potential of double corrugated regenerators to enhance the cooling power of an elastocaloric device that would be operating under compression loading was investigated. The numerical performances of two types of double corrugated geometries are presented and compared to a flat plate regenerator as a reference. The double corrugated geometry significantly increases the surface area to volume ratio and convection of the regenerator, which allows an increase in the power density of the device.

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