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- Högberg, Marine, 1962, et al.
(author)
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Calculation methods for comparing the performance of pure and mixed working fluids in heat pump applications
- 1993
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In: International Journal of Refrigeration. ; 16:6, s. 403-413
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Journal article (peer-reviewed)abstract
- Three methods for comparing cycle performance of working fluids, pure as well as non-azeotropic mixtures, are investigated for two applications and for two mixture pairs, HCFC22-CFC114 and HCFC22-HCFC142b, and their pure components. The methods differ in the way of calculating the heat exchange processes. They assume, respectively, equal minimum approach temperatures, equal mean temperature differences and equal heat transfer areas. Changes of coefficient of performance (COP) with composition are explained for all methods. It is shown that transport properties must be taken into account when making rigorous comparisons between working fluids. To predict the relations between fluids with high accuracy, one must use the method with equal heat transfer areas. By the method with equal mean temperature differences, the COP can be estimated with the same accuracy for mixtures as for pure fluids, and can be used for rough estimations of the COP level with different fluids. The method of equal minimum approach temperatures should be avoided for non-azeotropic mixtures.
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| 6. |
- Högberg, Marine, 1962, et al.
(author)
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Nonazeotropic mixtures as replacements for CFC12
- 1993
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In: presented at the 11th International Congresse of Chemical Engineering, Chemical Equipment Design and Automation, Prague, Czech Republik, August 29-September 3, 1993.
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Conference paper (peer-reviewed)
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| 7. |
- Strömberg, Jan, 1962, et al.
(author)
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Consequences of recent gas turbine developments for industrial CHP applications
- 1993
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In: Heat Recovery Systems & CHP. ; 13:3, s. 219-231
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Journal article (peer-reviewed)abstract
- Developments in gas turbine (GT) technology have been considerable during the last few years. In this paper, consequences regarding the technical performance for industrial combined heat and power applications are discussed and the most important design parameters are identified. Some GT types, which represent different stages of the developmental trend, are analysed in the simple and the combined cycle. Both the industrial and the aero-derivative GT classes are included. Conclusions are: (i) Generally, the developments have broadened the span of achievable power-to-heat ratios (α-values). Values between 0 and 1.5 are obtainable for different GT-based schemes with acceptable total efficiencies. (ii) The total efficiencies achievable depend strongly, and differently for different GT types, on the nature of the heat demands in the industrial process. (iii) When opportunities do not exist to cool the exhaust gases in an economizer, i.e. when the stack temperature is directly given by process heat demands, the total efficiency is independent of the GT class. For both classes, however, the development has led to higher total efficiencies when the process temperature demands are high. (iv) When opportunities exist to cool the exhaust gases in an economizer (which is often the case for the simple cycle and always for the combined cycle), the industrial GT developments have given improved ability to reach a high total efficiency. The new aero-derivative types, on the contrary, are worse than the conventional ones in this respect. This can also lead to worse performance in combined cycles for the new aero-derivative types. (v) When supplementary firing is applied, however, the total efficiency is high and similar for all various units and conditions. The ‘new aero-derivative’ units have, in that case, superior α-values—especially in the combined cycle.
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| 8. |
- Wallin, Erik, 1959, et al.
(author)
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Integration of heat pumps in industrial processes
- 1993
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In: Presented at 11th International Congress of Chemical Engineering, Chemical Equipment design and Automation. Praha, Czech Republic, August 29-September 3, 1993. - 1103-2952.
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Conference paper (peer-reviewed)
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| 9. |
- Wallin, Erik, 1959, et al.
(author)
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Process integration of industrial heat pumps
- 1993
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In: Presented at 4th International Energy Agency Heat Pumps Conference Maastrict, The Netherlands, April 26-29, 1993.
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Conference paper (peer-reviewed)
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