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Experimental investigations of low-temperature driven ejector for isobutane.

Number: pap. 2689

Author(s) : BERGANDER M. J., BUTRYMOWICZ D., SMIERCIEW K., et al.

Summary

The paper describes experimental and numerical investigation of ejection refrigeration system dedicated for short time storage of food products for local retail market, especially in rural areas. The work was sponsored by US Dept. of Agriculture under Phase I SBIR program. This novel method does not use electricity from the power grid and is cleaner for the environment than other refrigeration techniques. One of major problems in the retail market of perishable foodstuff is a lack of efficient refrigerated storage capacity. Existing technologies in most cases use conventional refrigeration systems that consume a large amount of electricity and use harmful working substances - usually harmful Freons, with high greenhouse effect and ozone depletion potential. In addition, ensuring the stability of the product temperature and humidity may be a challenge for most of the existing short time storage refrigerators. Responding to these challenges authors describe a new, ejector based refrigeration system that 1) utilizes solar or waste heat (below 100°C temperature) as a main source of energy, 2) eliminates the mechanical compressor, which is a main user of electricity and the main contributor to maintenance and reliability issues in cooling systems and 3) operates without any ozone depletion effects and any greenhouse gas emissions, when used with natural refrigerants. Until recently, ejector use in refrigeration systems was considered as controversial because most of the research conducted in the past has yielded only theoretical results without visible, commercial products. The main issue was a relatively low value of coefficient of performance (COP) in comparison with classical compression systems. Selection of the working fluid is the crucial problem because the system efficiency is strongly influenced by the thermodynamic properties of the refrigerant. It was found that the maximum efficiency was achieved with natural refrigerants, of which isobutane is the most favorable. However, primarily due to its flammable nature, it is not currently allowed in commercial systems in USA and Canada although it has been used for many years in all domestic refrigerators in Germany and other EU countries. For US market, two other environmentally friendly equivalents to isobutene were identified: R245fa and R1234ze both with zero ozone depletion potential. The research described here had overcome another limitation - a lack of appropriate methods for the design of ejector geometry. Such methodology was developed and tested in a variety of thermodynamic cycles for cooling, heating and heat pumps. The test stand and the experimental results of investigation for isobutane as a working fluid along with CFD modeling results are shown and discussed in the paper in details.

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Pages: 10

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Details

  • Original title: Experimental investigations of low-temperature driven ejector for isobutane.
  • Record ID : 30018833
  • Languages: English
  • Source: 2016 Purdue Conferences. 16th International Refrigeration and Air-Conditioning Conference at Purdue.
  • Publication date: 2016/07/11

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