| 1. |
- Castro Flores, José Fiacro, et al.
(författare)
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Energetic and exergetic analysis of a low- Temperature based district heating substation for low energy buildings
- 2015
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Ingår i: ECOS 2015 - 28th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems. - : International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems. - 9782955553909
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Konferensbidrag (refereegranskat)abstract
- District Heating (DH) technology contributes to the low GHG emissions energy system, facilitates a renewable energy usage, and increases the overall system efficiency, while providing the necessary heating services to the built environment. However, the existing DH technology may not be technically and economically effective to service buildings with low-energy demands. Here, low- Temperature based district heating (LTDH) provides a better match between supply and demand in terms of energy quality. This paper deals with the energy and exergy analyses of a LTDH substation supplying a secondary LTDH network as a subnet of the existing DH system. The substation is supplied with a mix of supply and return flows from the main DH network. An energy and exergy analysis was employed based on modelling and simulation to compare the performance of two proposed substation configurations to that of a conventional DH substation operating at low- Temperature. The study was performed for a year round outdoor temperatures scenario under steady-state conditions. The exergy destruction at the system components was identified and compared. The results of this analysis show that by using the low- Temperature flow from the DH return pipe, the final exergy efficiency of the overall system is increased. On the other hand, assuming an adiabatic system the energy performance stays the same. As compared with the conventional DH network, the integration of the proposed LTDH substation reduced the share of energy demand covered by the main DH supply by 20-25% and improved the overall exergy efficiency from 79% to 85-87% depending on the substation configuration. Based on the results, the solution presented is seen as an effective approach to reduce the system's losses, and to increase the quality match between the low-energy heating demands and the supply.
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| 2. |
- Chiu, Justin N. W., et al.
(författare)
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Industrial surplus heat transportation for use in district heating
- 2016
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Ingår i: Energy. - : Elsevier. - 0360-5442 .- 1873-6785. ; 110, s. 139-147
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Tidskriftsartikel (refereegranskat)abstract
- M-TES (Mobile Thermal Energy Storage) technology is explored in this paper for transportation of industrial surplus heat for use in LTDH (low temperature district heating network). LTDH has promising potential in utilizing low grade heat, on the other hand, 20%–50% of industry generated surplus heat is often released to the ambient environment. M-TES is used to match thermal energy supply and demand that occur at different locations and that are shifted in time. In this paper, design of M-TES is conducted, optimization in operating strategies is performed, sensitivity analysis on levelized cost is studied, and environmental impact of CO2 emissions due to transportation is evaluated. The results of the study show an array of transportation means and storage operating strategies under which M-TES is technically, economically and environmentally sound for transportation of industrial surplus heat for use in LTDH network.
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| 3. |
- Paudel, S., et al.
(författare)
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Wind resource assessment in Europe using emergy
- 2014
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Ingår i: Journal of Environmental Accounting and Management. - : L and H Scientific Publishing, LLC. - 2325-6192 .- 2325-6206. ; 2:4, s. 347-366
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Tidskriftsartikel (refereegranskat)abstract
- In a context of increasing use of renewable sources, it is of importance to correctly evaluate the actual sustainability of their implementation. Emergy analysis is one of the possible methods useful for such an assessment. This work aims to demonstrate how the emergy approach can be used to assess the sustainability of wind energy resource in Europe. The Emergy Index of Sustainability (EIS) and the Emergy Yield Ratio (EYR) are used to analyze 90 stations of European regions for three types of wind turbines. To do so, the simplified Chou wind turbine model is used for different set of parameters as: nominal power and size of the wind turbines, and cut-in and cut-out wind speeds. Based on the calculation of the emergy indices, a mapping is proposed to identify the most appropriate locations for an implementation of wind turbines in European regions.The influence of the wind turbine type on the sustainability is also analyzed, in link with the local wind resource. Thus, it is concluded that the emergy sustainability indices are sensitive to the wind turbine design parameters (size, cut-in and cut-outwind speed).
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