| 1. |
- 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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| 2. |
- 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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| 3. |
- Berntsson, Thore, 1947
(författare)
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Värmepumpar
- 1990
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Ingår i: Föredrag vid konferens Elmia Energi & Miljö 90, Jönköping.23-27 april 1990.
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Konferensbidrag (refereegranskat)
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| 4. |
- Franck, Per-Åke, 1953, et al.
(författare)
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Process integration of various types of heat pumps
- 1990
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Ingår i: Föredrag vid BHRA International Conference on Applications and Efficiency of Heat Pump Systems in Environmentally Sensitive Times, Munchen, Västtyskland. 1-3 Oktober 1990.
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Konferensbidrag (refereegranskat)
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| 5. |
- Holmberg, Per, 1957, et al.
(författare)
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Technico-economic aspects on heat transformers
- 1990
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Ingår i: Paper to be presented at Workshop on Concepts for energysavings in Heat Pumps and Refigeration Systems August 31st 1990 at The Royal Inst. of techn.,Sthlm.
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Konferensbidrag (refereegranskat)
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| 6. |
- Högberg, Marine, 1962, et al.
(författare)
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Energy aspects in CFC-developments
- 1990
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Ingår i: Presented at Workshop on Concepts for Energy Savings in Heat Pumps and Refrigeration Systems, KTH, Stockholm August 29-31, 1990. ; , s. 13-
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In the search for substitutes for teday's CFC fluids in electrically driven heat pumps the aspect of any changes in the electricity consumption is, of course, crucial. Reliable data on this aspect can only be achieved from full-scale experimental plants. However, in order to identify new fluids of interest, theoretical system simulations must be carried out in parallel with experimental projects. In such simulations the optimal equipment design for each new fluid can also be identified. In this paper some results from heat pump cycle calculations with different CFC substitutes are presented. From these results conclusions are drawn on the possible impact on the electricity consumption in future heat pump systems. A sensitivity analysis on some of the most important uncertainty factors in system simulations with new fluids is also presented.
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| 7. |
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| 8. |
- Vamling, Lennart, 1954, et al.
(författare)
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CFC Alternatives for High-Temperature Heat Pump Application
- 1990
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Ingår i: BHRA International Conference on Applications and Efficiency of Heat Pump Systems in Environmentally Sensitive Times, Munich 1st to 3rd October 1990. ; , s. 17-
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 9. |
- Wallin, Erik, 1959, et al.
(författare)
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Heat pumps in industrial processes - an optimization methodology
- 1990
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Ingår i: Heat Recovery Systems & CHP. ; 10:4, s. 437-446
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Tidskriftsartikel (refereegranskat)abstract
- The optimal integration of heat pumps in industrial processes has not yet been fully understood. In this paper an optimization methodology and a method which uses the composite curves as a guideline to the correct choice of heat pump type are outlined. The selection is done by matching the shape of the composite curves against the specific characteristics of several heat pump types. Furthermore, a methodology for the optimization of the most important parameters in a heat pump system is presented. In the optimization methodology the annual cost is minimized by varying heat source and heat sink temperatures, the heat pump size and the stream or streams to be utilized as heat source and heat sink.To reveal the potential for electrically driven compression heat pumps two different examples were studied with the methodology. The first example had close composite curves and was thought to be a poor heat pump candidate. The second one had open composite curves and was thought to be a promising example. The results showed that for both examples, heat pump installations were advantageous under good economic conditions for the heat pump, i.e. low electricity price, high fuel price and low investment costs. Also reasonable payback periods were achieved. With more unfavourable conditions the payback period increased, and in extreme cases a heat pump was no longer a better alternative than pure heat exchange. This decline in potential for heat pumping was much less in the example with open composite curves than in the example with closed ones. However, the conclusion to be drawn is that there exists today a potential for heat pumps in industrial processes.
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| 10. |
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