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9 This paper emphasizes on improvement in energetic performance of a vapour compression refrigeration cycle (VCR). In last two decades, the upheaval in refrigeration sector has led to replacement of conventional refrigerants with non-ozone depleting and low global warming potential refrigerants. Most of alternate refrigerants which have low global warming potential, have usually low energy efficiency (coefficient of performance i.e. COP). To overcome the problem of low energy efficiency, a Vortex Tube integrated subcritical Vapour Compression cycle (VTVCR) has been considered based on Keller model. Vortex Tube integrated cycles are trans-critical in nature based on different models such as Maurer and Keller models. The Keller model has been mostly used in past for transcritical VTVCR with CO2 as refrigerant which have a low critical temperature of 87.8°F (31℃). In this work, Keller model is used in subcritical mode for refrigerants which have critical temperatures higher than ambient temperature in hot climatic conditions. This cycle operates at three pressure levels i.e. lowest pressure (in evaporator), intermediate pressure (in vortex tube) and highest pressure (in condenser). A computer program has been developed in EES software for the analysis of this cycle. The results have been computed for simple saturated VCR and are compared with VTVCR with R134a as refrigerant. The results show that the COP of the VTVCR is higher than simple saturated VCR and depends on intermediate temperature and pressure. Both specific cooling effect and specific compressor power for this cycle are higher than corresponding values for simple saturated VCR. The increase in both specific cooling effect and compressor work bring an increase in the COP by 18.8% at evaporator temperature of -67°F (-55°C) to 4.27% at 32°F (0°C) evaporator temperature. The optimum intermediate temperature and pressure are also computed for maximum COP. It is observed that optimum intermediate pressure is 0.47 to 0.5 times the geometric mean of evaporator and condenser pressures. It is also observed that for cold mass fraction value of 0.4 in the vortex tube, the increase in the value of COPke of the VTVCR is minimum when compared to simple saturated VCR.
Citation: 2019 Annual Conference, Kansas City, MO, Conference Papers
Product Details
- Published:
- 2019
- Number of Pages:
- 9
- Units of Measure:
- Dual
- File Size:
- 1 file , 650 KB
- Product Code(s):
- D-KC-19-C005
