Change search
ReferencesLink to record
Permanent link

Direct link
Carbon Dioxide in Supermarket Refrigeration
KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
2008 (English)Doctoral thesis, monograph (Other scientific)
Abstract [en]

This thesis theoretically and experimentally investigates different aspects of the application of CO2 in supermarket refrigeration. Theoretical analysis has been performed using computer simulation models developed to simulate CO2 indirect, NH3/CO2 cascade, CO2 trans-critical and direct expansion (DX) R404A systems. The models supported the selection of the CO2 system solutions to be tested experimentally and facilitated the design of NH3/CO2 cascade and trans-critical systems test rigs. Performance evaluation and systems’ optimizations have also been carried out.

In order to verify the findings of the theoretical analysis an experimental evaluation has been performed whereby a scaled-down medium size supermarket has been built in a laboratory environment. NH3/CO2 cascade and trans-critical systems have been tested and compared to a conventional R404A system installed in the same laboratory environment. Experimental findings have been compared to the computer simulation models.

In supermarket refrigeration applications, safety is a major concern because of the large number of people that might be affected in the event of leakage. Therefore, a computer simulation model has been developed to perform calculations of the resulting concentration levels arising from different scenarios for leakage accidents in the supermarket. The model has been used to validate some of the risks associated with using CO2 in the application of supermarket refrigeration.

Results of the experiments and the computer simulation models showed good agreement and suggest that the NH3/CO2 cascade system is a more efficient solution than the analyzed conventional ones for supermarket refrigeration. On the other hand, CO2 trans-critical solutions have efficiencies comparable to the conventional systems analyzed, with potential for improvements in the trans-critical systems. From a safety point of view, the analysis of the calculations’ results clearly shows that using CO2 in supermarket refrigeration does not create exceptional health risks for customers and workers in the shopping area.

Studies conducted in this thesis prove that the CO2 systems investigated are efficient solutions for supermarket refrigeration.

Place, publisher, year, edition, pages
Stockholm: KTH , 2008. , vii, 153 p.
Trita-REFR, ISSN 1102-0245 ; 08/60
Keyword [en]
CO2, carbon dioxide, refrigeration system, supermarket, cascade, indirect, trans-critical, modelling, simulation, experiment, safety analysis, comparison
National Category
Energy Engineering
URN: urn:nbn:se:kth:diva-4753ISBN: 978-91-7178-965-5OAI: diva2:13782
Public defence
2008-06-04, M3, KTH, Brinellvägen 64, Stockholm, 09:00
QC 20100909Available from: 2008-05-16 Created: 2008-05-16 Last updated: 2010-09-09Bibliographically approved

Open Access in DiVA

fulltext(2436 kB)5426 downloads
File information
File name FULLTEXT01.pdfFile size 2436 kBChecksum MD5
Type fulltextMimetype application/pdf

Search in DiVA

By author/editor
Sawalha, Samer
By organisation
Applied Thermodynamics and Refrigeration
Energy Engineering

Search outside of DiVA

GoogleGoogle Scholar
Total: 5426 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 1123 hits
ReferencesLink to record
Permanent link

Direct link