| 1. |
- Sandvall, Akram, 1976, et al.
(författare)
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Cost-efficiency of Urban Heating Strategies – Modelling Scale Effects of Low-energy Building Heat Supply
- 2017
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Ingår i: Energy Strategy Reviews. - : Elsevier BV. - 2211-467X. ; 18, s. 212-223
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Tidskriftsartikel (refereegranskat)abstract
- There is now a strong demand in Sweden for construction of new low energy buildings (LEB) areas. Thereare essentially three options for heat supply to these LEB areas: “individual”, “on-site” and “large heatnetwork” supply. The chosen option is of strategic societal interest. Thus, this study aims at comparingthe long-term system cost of the three heat supply options. A dynamic modelling approach is applied in asystematic analysis designed to investigate the threshold for the various options' cost-efficiency. Thestudy addresses scale impacts of hypothetical LEB areas and district heating systems. The results showthat, generally, the large heat network option has the lowest system cost whereas in most cases theindividual option has the highest system cost.
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| 2. |
- Sandvall, Akram, 1976, et al.
(författare)
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ECONOMICALLY OPTIMAL HEAT SUPPLY TO LOW ENERGY BUILDING AREAS
- 2016
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Ingår i: The 15th International Symposium on District Heating and Cooling.
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Konferensbidrag (refereegranskat)abstract
- European Directives and Swedish national goals aim at increasing buildings’ energy efficiency. The construction of low energy building (LEB) areas in Sweden has increasingly attracted attention due to national support. Compared to conventional buildings, LEBs require little space heating during the cold seasons. Still, there are various options for supply of the required heating. Thus, this study aims at comparing the long-term system cost of three heat supply options to a hypothetical LEB area assumed to be located close to an urban area: an “individual” (i.e. separate heat supply), an “on-site” (i.e. local district heating (DH) system) and a “large heat network” (i.e. heat production in a nearby DH system and transmission to the LEB area). A dynamic approach is applied allowing the heat supply system to develop with time, and an energy system model being able to account for the interactions between the building, heat and power sectors, is utilised for the calculations. Two climate policy scenarios are applied to address the uncertainty in future energy prices etc. A systematic sensitivity analysis is designed to investigate the threshold for cost-effectiveness of the large heat network option compared to the other two options. The sensitivity analysis takes into account different combinations of three key parameters: plot ratio of the LEB areas, specification of nearby DH, and distance between LEB area and nearby DH system. The results show, for most of the tested combinations and under both scenarios, that heat supply from the nearby DH system has the lowest system cost if the distance to this system is no more than 2 km, because of the low-cost sources of heat available in the large DH system. A local DH system is more cost-effective than individual heating of buildings even in a LEB area, if it is densely built.
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| 3. |
- Sandvall, Akram, 1976, et al.
(författare)
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Low-energy buildings heat supply–Modelling of energy systems and carbon
- 2017
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Ingår i: Energy Policy. - : Elsevier BV. - 0301-4215. ; 111, s. 371-382
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Tidskriftsartikel (refereegranskat)abstract
- Construction of new low-energy buildings (LEB) areas is attracting attention as a climate mitigation measure.Heat can be supplied to buildings in these areas through individual solutions, through a small, on-site heatnetwork, or through a heat connection to a close-by district-heating (DH) system. The choice between theseoptions affects the energy supply systems and their carbon emissions far beyond the LEB area. We compare thelong-term systems impacts of the three heat-supply options through dynamic modelling of the energy systems.The study draws on data collected from a real LEB area in Sweden and addresses scale-dependent impacts ondistrict heating systems. The results show that, generally, the individual and on-site options increase biomassand electricity use, respectively. This, in turn, increases carbon emissions in a broader systems perspective. Thesystems impacts of the large heat network option depend on the scale and supply-technologies of the DH systemclose to the LEB area.
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| 4. |
- Sandvall, Akram, 1976, et al.
(författare)
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Modelling environmental and energy system impacts of large-scale excess heat utilisation – A regional case study
- 2015
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Ingår i: Energy. - : Elsevier BV. - 0360-5442. ; 79:C, s. 68-79
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Tidskriftsartikel (refereegranskat)abstract
- EH (excess heat) is an important, but yet partially unused, source for DH (district heating). This study analyses energy system and CO2 emission impacts at a regional scale of integration of EH from a large chemical cluster and local DH systems. The assessment is carried out with the optimising energy systems model MARKAL_WS, in which the DH systems in the Västra Götaland region of Sweden are represented individually. In addition, options for transport biofuel production are included. The results show that the connection contributes to a reduction of biomass and fossil fuel use, and to a related reduction of CO2 emissions, in the DH systems. This opens opportunities for earlier production of transport biofuels but instead electricity generation from combined heat and power plants in the region decreases. In the short term, total CO2 emissions increase if an expanded systems view is applied in which effects on the DH systems, transport system and European electricity system are accounted for, while in the mid-term they decrease. The study is based on a case and due to the diversity of Swedish DH systems in terms of use of fuels and local available resources, a generalisation of the results is not straightforward.
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| 5. |
- Sandvall, Akram, 1976, et al.
(författare)
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System profitability of excess heat utilisation – A case-based modelling analysis
- 2016
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Ingår i: Energy. - : Elsevier BV. - 0360-5442. ; 97, s. 424-434
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Tidskriftsartikel (refereegranskat)abstract
- The use of EH (excess heat) in DH (district heating) may contribute to increased sustainability through reduced use of primary energy. In Sweden, while biomass has become the most important DH fuel during the last decades, there is a significant amount of industrial EH that could be utilised in the DH systems if it could be shown to be an economically viable alternative. This study addresses the long-term system profitability of a large heat network between a cluster of chemical industries and two DH systems that enables an increased use of EH. An assessment is carried out by scenario and sensitivity analyses and by applying the optimising energy systems model MARKAL_WS, in which the DH systems of the Västra Götaland region of Sweden are represented individually. The results show heat network profitability under most assumptions, and that the profitability increases with biomass competition, phase-out of natural gas use and higher CO2 charges, whereas it decreases with the availability of other EH sources in the base load of the DH systems.
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