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- Albert, Ludvig, et al.
(författare)
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Icke-azeotropa blandningar i värmepumpar - Förstudie för fullskaleprojekt
- 1990
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In cooperation between STAL Refrigeration AB and the Department of Heat and Power Technology, Chalmers University of Technology, an experimental heat pump with a nonazeotropic mixture as working fluid is being prepared. This will be the first full scale plant in Sweden.This report contains the results from a pre-study to thefull scale project. The influence of a non-azeotropic mixture, as compared with a pure fluid on the design of the components in the heat pump, has been analyzed. This study has partly been done with a previously developed computer program, which has been improved. Some supplementary routines have been added to it, and the specific design of the prepared experimental planthas been inserted.The experimental heat pump which is to be used, has a countercurrent evaporator and a crosscurrent condenser. Since the best design for a non-azeotropic mixture is countercurrent, heat exchanger calculations have been done for this type of condenser. Comparisons indicate that a shell and tube heat exchanger with the non-azeotropic mixture on the shell side is highly interesting to investigate practically. The study of the internal heat exchanger shows that the dependence of COP on the degree of superheat before the compressor is slightly larger for a non-azeotropic mixture than for a pure fluid.During this project and also afterwards a dynamic debate onthe environmental effect of "CFCs" has been going on. Theuse of the mixture HCFC22/CFCl14, suggested in this report,will be forbidden in the future. However, it is stillinteresting to study it, since there are more and betterthermodynamic and physical data available for this mixturethan for other non-azeotropic mixtures. The experience andknowledge acquired in this project are possible to apply onother mixtures. Accurate calculations can be done for thesewhen more reliable data are available.
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- Albert, Ludvig, et al.
(författare)
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Provning av icke azeotropiska arbetsmedieblandningar i större värmepumpar
- 1990
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Ett fullskaleprov har genomförts med en ickeazeotrop blandning av HCFC22 och CFC114 i en enstegs värmepump. Mätningar och utvärdering har gjorts i samarbete mellan Institutionen for Värmeteknik och maskinlära och STAL refrigeration AB. Den använda värmepumpen är en av STALs testriggar vid fabriken i Norrköping. STAL har ansvarat for utförande och utvärdering av mätningarna medan Institutionen for Värmeteknik och maskinlära genomfort en jämförelse mellan matresultat och datorsimuleringar.Fullskaleprovet har visat att användning av arbetsmedieblandningar som ersättning av CFC12 i befintliga aggregat, åtminstone av den typ som provats, ar tekniskt mojlig. Betydande insatser återstår dock for att uppnå den säkerhet, servicevanlighet och lönsamhet som stalls på värmepumpar arbetande med rena arbetsmedier. En del registrativa frågor, sa som faststallande av tillåtet drifttryck, dimensionering av säkerhetsventiler, hantering av arbetsmedier etc, for blandningar måste lösas.Utvärdering av referensprov med HCFC22 visade att förångarens kapacitet inte var sa hög som förväntat. Troliga orsaker kan vara kraftig snedfördelning av arbetsmediet mellan tuberna alternativt att kontakten mellan rörväggen och insaten i tuberna varit dalig. Vid fortsatta simuleringar beaktades förångarens laga kapacitet på samma sätt for rena ämnen som for blandningar. Jämförelser mellan simulering och matning for blandningarna antyder att det masstransportmotstånd som förekommer vid förångning av en blandning inte har sa stort inflytande som man tidigare hävdat. Nar masstransportmotståndet försummades fick vi lika god överensstämmelse mellan matning och simulering för blandningarna av HCFC22/CFC114 som för ren HCFC22.
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- Caldenby, Claes, 1946
(författare)
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Konstruktivism och dekonstruktion
- 1990
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Ingår i: Arkitektur. ; :3, s. 26-35
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Ett försök montera isär dekonstruktivismen och frilägga påverkan från den sovjetiska konstruktivismen och den filosofiska dekonstruktionen.
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- Danhäll, D, et al.
(författare)
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Naturligt grupperat arbete vid Volvo Lastvagnar – Slutrapport
- 1990
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Consumer report for the company in question (the Volvo Truck Company) which is financed by the company and partly also by a research foundation. It is a matter of a work that in this particular case were carried out during nine years in a number of experimental workshops located outside the Chalmers University of Technology. These workshops were financed by the Volvo Automobile and Truck companies. This achievement, as the final contribution to the Swedish automotive industry after having already treated this research field/problem area for more than two decades before this particular period if time (involving several junior and senior research competencies, as well as industrial and governmental foundings). A comment: As was the praxis during this (early) period of time at Chalmers University of Technology, as well as probably at some other universities. This means that frequent and vast academic publication by means of e.g. conference papers and refereed contributions to scientific journals was almost unheard of. At least so for some of the applied science disciplines. However, today are the situation indeed very different (i.e. earlier was the publication in many respects focused on trying to satisfy the executive administrator the research foundation in question etc.). To be more precise, this early praxis was definitively the case for the research and development work carried out at the Department of Transportation (a broadly applied science discipline), which was characterized by more practical strives to e.g. engineer research results. Rather than relying on truer scientific efforts in a narrower sense. Functional satisfaction (i.e. something engineered work as planned instead verification/falsification of a hypothesis) was judged as being a primary aim of this research and development work. Therefore are (in the context of the publications registered in Chalmers Public Library CPL) the author making distinctions between consumer reports, on one hand. And, one the other hand, reports and preprints (manuscripts), while instead the academically orientated publications are various sort of scientific contributions presented at conferences or published in scientific journals (actually it is somewhat more complex, but further explanations are omitted here). The consumer reports were aimed at a various external organization with who the authors cooperated, and these are in many cases not available in PDF format to be easily read by logging in at CPL. This particular approach has judged as being fair/relevant fair in order to mirror of work conducted by the author or authors during the passing decades. Besides, the competencies at Chalmers Library, who actually have been very helpful, have not managed to provide appropriate answers to the various questions implied being at hand just above (this despite trying to get hold of such answers, hence this very comment).
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