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Open Issues in Control of Automotive R744 Air-Conditioning Systems
Dalarna University, School of Technology and Business Studies, Electrical Engineering.
2007 (English)Independent thesis Advanced level (degree of Master (Two Years))Student thesis
Abstract [en]

In this thesis, one of the current control algorithms for the R744 cycle, which tries to optimize the performance of the system by two SISO control loops, is compared to a cost-effective system with just one actuator. The operation of a key component of this system, a two stage orifice expansion valve is examined in a range of typical climate conditions. One alternative control loop for this system, which has been proposed by Behr group, is also scrutinized. The simulation results affirm the preference of using two control-loops instead of one loop, but refute advantages of the Behr alternate control approach against one-loop control. As far as the economic considerations of the A/C unit are concerned, using a two-stage orifice expansion valve is desired by the automotive industry, thus based on the experiment results, an improved logic for control of this system is proposed. In the second part, it is investigated whether the one-actuator control approach is applicable to a system consisting of two parallel evaporators to allow passengers to control different climate zones. The simulation results show that in the case of using a two-stage orifice valve for the front evaporator and a fixed expansion valve for the rear one, a proper distribution of the cooling power between the front and rear compartment is possible for a broad range of climate conditions.

Place, publisher, year, edition, pages
Borlänge, 2007. , 64 p.
Keyword [en]
R744, Air-Conditioning, COP, Cooling power, optimization, two-stage orifice valve, Two-evaporator
Identifiers
URN: urn:nbn:se:du-2963OAI: oai:dalea.du.se:2963DiVA: diva2:518308
Uppsok
Technology
Supervisors
Available from: 2007-10-23 Created: 2007-10-23 Last updated: 2012-04-24Bibliographically approved

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CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf