Investigation of using Internal Heat Exchangers in CO2 Trans-critical Booster System
2014 (English)In: 11th IIR Gustav Lorentzen Conference on Natural Refrigerants: Natural Refrigerants and Environmental Protection, GL 2014, 2014, 453-460 p.Conference paper (Refereed)
This paper theoretically investigates the performance of a CO2 trans-critical booster system using various configurations of internal heat exchangers (IHX). A reference case performance is compared with eight alternatives of using IHXs after the gas cooler and liquid receiver. Cooling COP, total COP and amount of heat recovery are the comparison criteria. Heat recovery or heat rejection from the discharge gas of low stage compressors is another modification examined in this study.
According to the results, no significant improvement is found by using internal heat exchanger (IHX) focusing only on the cooling COP. Considering simultaneous refrigeration and heat recovery for a sample 65 bar discharge pressure, up to 12% efficiency improvement with IHX A-AC-AD for a system “with by-pass” and up to 11% improvement with IHX AC-AD-BC-BD for a system “without by-pass” is calculated. It is shown that superheating has less influence on the available heat to be recovered in the trans-critical region in comparison with the sub-critical region. Furthermore, low stage level heat recovery and de-superheating improves the efficiency 3-4% for the cases with high amount of de-superheating at low stage suction line, using IHX C or D.
To conclude, using IHXs improves the performance of the CO2 booster system with heat recovery. This improvement is more significant in sub-critical region.
Place, publisher, year, edition, pages
2014. 453-460 p.
Supermarket, Carbon dioxide (CO2), Refrigeration, Heat recovery, Internal heat exchangers (IHX)
IdentifiersURN: urn:nbn:se:kth:diva-175686ScopusID: 2-s2.0-84932105055ISBN: 978-236215004-3OAI: oai:DiVA.org:kth-175686DiVA: diva2:861915
11th IIR Gustav Lorentzen Conference on Natural Refrigerants; Hangzhou, China, August 31-September 2, 2014
FunderSwedish Energy Agency, EP06
QC 201512162015-10-192015-10-192015-12-16Bibliographically approved