| 1. |
- Ayele, Getnet Tadesse, 1987-, et al.
(författare)
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Electrified district heating networks : a thermo-economic optimisation based on exergy and energy analyses
- 2021
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Ingår i: International Journal of Exergy. - : Inderscience Publishers. - 1742-8297 .- 1742-8300. ; 35:1, s. 100-131
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a thermo-economic optimisation of an electrified district heating network consisting of wind power plant, gas-fired combined heat and power plant and heat pumps. The load flow problem of the resulting multi-energy system is formulated by considering all physical and operating parameters in both of the electricity and heat distribution networks. First, energy and exergy analyses are applied to identify and isolate lossy branches of a meshed heating network. This is followed by the optimal placement of heat pumps. Finally, supply and return temperatures are optimised. Particle swarm optimisation technique is implemented in order to find the best place of heat pumps, their economical dispatch and optimal temperature profile of the district heating network. Results show that up to 59.12% of the distribution heat loss and 9.37% of the operating cost can be saved by following a step-by-step methodology discussed in this paper.
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| 2. |
- Gong, Mei, 1967-, et al.
(författare)
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Coordination of exergy analysis and the MIND method - applied to a pulp and board mill
- 2004
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Ingår i: International Journal of Exergy. - 1742-8297 .- 1742-8300. ; 1:3, s. 289-302
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Tidskriftsartikel (refereegranskat)abstract
- The MIND (Method for analysis of INDustrial energy systems) method has been developed for cost optimisation of industrial energy systems, mainly with regard to quantities of energy. Exergy analysis reveals losses, efficiencies and possible improvements. These methods can be combined in order to improve industrial energy systems. In this paper, a Swedish pulp and board mill is used as a case study. The efficiencies of the processes in the mill are evaluated using exergy analysis. The most exergy inefficient processes are indicated and some improvements are suggested. This case study shows that it is the boilers and the evaporation plant that are the most inefficient processes, with efficiencies down to 29%. Different investment alternatives for these processes are studied and cost optimisation is achieved using the MIND method. The study shows that the energy costs can be reduced by up to 15 million Euros per year while the exergy efficiency can be improved by up to 14%. The combined approach shows that the energy cost-efficient alternatives are also usually exergy efficient.
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| 3. |
- Reifarth, Simon, et al.
(författare)
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Exergy and energy analysis of high-pressure and low-pressure exhaust gas recirculation system of a diesel engine
- 2015
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Ingår i: International Journal of Exergy. - 1742-8297 .- 1742-8300. ; 17:3, s. 313-334
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Tidskriftsartikel (refereegranskat)abstract
- The emission legislation for internal combustion engines is becoming increasingly stringent. Exhaust gas recirculation (EGR) is an important tool for emission control in modern diesel engines. This study compares the most common EGR-systems, high-pressure and low-pressure EGR, and focuses on single components. To analyse the gas exchange system, both energy and exergy analysis methods can be used. In this study, both methods are compared and specific advantages and disadvantages are shown. It is shown that the exergy analysis contains useful information for engine development regarding the efficiency of single components and their influence on the entire systems performance.
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