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Publikasjoner (10 av 27) Visa alla publikasjoner
Räftegård, O. & Dahl, J. (2023). Flexibility opportunities in a CHP and district heating system. RISE Research Institutes of Sweden
Åpne denne publikasjonen i ny fane eller vindu >>Flexibility opportunities in a CHP and district heating system
2023 (engelsk)Rapport (Annet vitenskapelig)
Abstract [en]

In this report, flexibility is discussed in terms of the ability of a unit or a system of units to change their electricity production or consumption to participate in these ancillary services. In district heating units, the electrical flexibility is strongly correlated with the thermal flexibility which in turn is very site specific. This report makes some proposals on what measures could be carried out to improve flexibility and grade them by implementation difficulty and cost estimates. Most of the measures refer to some upgrades in CHP plants to increase these plants’ flexibility potential towards the ancillary servics. These measures affect not only the electricity output of CHP plants but also the heat output. The report also discusses several means to access heat supply flexibility, to support the CHP plants’ power flexibility. This report also serves as an easy introduction to heat production in district heating systems and, in particular to CHP plants, targeted at experts in other fields to get a basic understanding of some technical aspects and limitations of district heating systems.

sted, utgiver, år, opplag, sider
RISE Research Institutes of Sweden, 2023. s. 21
Serie
RISE Rapport ; 2023:88
Emneord
CHP, flexibility, heat supply flexibility, ancillary services, district heating
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-73124 (URN)978-91-89821-61-3 (ISBN)
Tilgjengelig fra: 2024-05-13 Laget: 2024-05-13 Sist oppdatert: 2024-05-17
Räftegård, O. (2023). GRETA - Värdeskapande värmeåtervinning - delrapport sand.
Åpne denne publikasjonen i ny fane eller vindu >>GRETA - Värdeskapande värmeåtervinning - delrapport sand
2023 (svensk)Rapport (Annet vitenskapelig)
Abstract [en]

To recover heat from foundry sand to heat at such a high temperature that the heat is easy to use and distribute in the form of heating water or district heating requires sand coolers designed with that purpose. These exist but are not proven in the foundry industry. This report describes case studies that evaluated the issue at a Swedish sand foundry.

Publisher
s. 22
Serie
RISE Rapport ; 2023:97
Emneord
foundry, heat recovery, casting sand
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-67575 (URN)978-91-89821-75-0 (ISBN)
Merknad

Bakom projektet står ett stort antal gjuteriföretag och det statliga forskningsinstitutet RISE. Det pågår 2020-2023 och finansieras av Svenska Gjuteriföreningen och det strategiska innovationsprogrammet Metalliska material, en gemensam satsning av Vinnova, Energimyndigheten och Formas.

Tilgjengelig fra: 2023-10-30 Laget: 2023-10-30 Sist oppdatert: 2024-05-17bibliografisk kontrollert
Räftegård, O. (2023). GRETA - värdeskapande värmeåtervinning - delrapport svalnande gjutgods.
Åpne denne publikasjonen i ny fane eller vindu >>GRETA - värdeskapande värmeåtervinning - delrapport svalnande gjutgods
2023 (svensk)Rapport (Annet vitenskapelig)
Abstract [en]

GRETA - value adding heat recovery - report cooling of castings

In the case study at a Swedish iron foundry, the opportunity of recovering waste heat from cooling goods has been studied. Probably, the most reasonable practical solution is to place the goods in a cooling hut/cooling oven after the break away of sand and mould. The cooling hut’s air cools the goods under controlled conditions. The air, in turn, can be cooled with hot cooling water, which in turn would be cooled by district heating. Alternatively, the hot air can be used directly to heat up nearby facilities. The foundry already has heat recovery from induction furnace cooling water and from compressed air units to a district heating network. The need for about 70°C heat is already saturated, while there is a demand for about 100°C heat. There is also plenty of 100°C waste heat, both in goods and sand. An alternative outlet could therefore be heat-driven electricity production. However, the electricity efficiency for this will be low, perhaps 5-10%. The remaining heat needs to be cooled, e.g. with surface water.

Publisher
s. 34
Serie
RISE Rapport ; 2023:96
Emneord
foundry, heat recovery, castings
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-67576 (URN)978-91-89821-74-3 (ISBN)
Merknad

Bakom projektet står ett stort antal gjuteriföretag och det statliga forskningsinstitutet RISE. Det pågår 2020-2023 och finansieras av Svenska Gjuteriföreningen och det strategiska innovationsprogrammet Metalliska material, en gemensam satsning av Vinnova, Energimyndigheten och Formas.

Tilgjengelig fra: 2023-10-30 Laget: 2023-10-30 Sist oppdatert: 2024-05-17bibliografisk kontrollert
Räftegård, O. (2023). GRETA - Värdeskapande värmeåtervinning - delrapport värmebehandlingsugn.
Åpne denne publikasjonen i ny fane eller vindu >>GRETA - Värdeskapande värmeåtervinning - delrapport värmebehandlingsugn
2023 (svensk)Rapport (Annet vitenskapelig)
Abstract [en]

GRETA - value adding heat recovery - report heat treatment furnace

Recovering heat from exhaust gas from heat treatment furnaces is technically simple and provides high temperature heat, e.g. 100°C heating water/district heating or steam. The process has been evaluated at Swedish steel foundry. A fairly rough estimate is that just under 50% of the used fuel (net calorific value a.k.a lower heating value) can be recovered from the flue gas assuming a standard burner is used. If the burner is regenerative/recuperative or oxy-fuel type, the amount of residual exhaust heat is significantly reduced, to perhaps 15-20% of the fuel input. Additional heat is available at lower temperatures, e.g. for preheating ventilation air. In the longer term, the transition to a sustainable society may change the amount of available exhaust gases, e.g. if electric furnaces without exhaust gases take over the market from combustion furnaces, or if e.g. fuel and oxygen prices in the future favour oxy-fuel burners. An accumulator tank that holds the heat equivalent to a batch is likely to be needed if the heat is to be used for comfort heating or similar purposes.

Publisher
s. 24
Serie
RISE Rapport ; 2023:98
Emneord
foundry, heat recovery, heat treatment furnace
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-67574 (URN)978-91-89821-76-7 (ISBN)
Merknad

Bakom projektet står ett stort antal gjuteriföretag och det statliga forskningsinstitutet RISE. Det pågår 2020-2023 och finansieras av Svenska Gjuteriföreningen och det strategiska innovationsprogrammet Metalliska material, en gemensam satsning av Vinnova, Energimyndigheten och Formas.

Tilgjengelig fra: 2023-10-30 Laget: 2023-10-30 Sist oppdatert: 2024-05-17bibliografisk kontrollert
Räftegård, O. (2023). GRETA - Värdeskapande värmeåtervinning - huvudrapport.
Åpne denne publikasjonen i ny fane eller vindu >>GRETA - Värdeskapande värmeåtervinning - huvudrapport
2023 (svensk)Rapport (Annet vitenskapelig)
Abstract [en]

GRETA - Value adding heat recovery - main report

The main report summarises the results of the case studies and for the waste heat sources for two heat demands. The waste heat sources are cooling systems for induction furnaces and compressed air, and heat recovery from goods, sand and heat treatment furnaces. The heat demands are district heating (incl. internal comfort heating) and heat-driven power generation. The case study at Baettr shows good availability and temperature in both sand and goods, but the sand is easier to access than the goods. The case study at Smålands stålgjuteri shows good availability, accessibility and temperature for recovery of exhaust gas heat from the heat treatment furnace. Both case studies show that the foundry's internal comfort heat demand is poorly matched to the supply in terms of availability. District heating is a good alternative if it is accessible (distance and interest from the utility). The supply of heat-driven power plants is limited, the electrical efficiency can be expected to be 5-10% of the supplied drive heat.

Publisher
s. 30
Serie
RISE Rapport ; 2023:95
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-67572 (URN)978-91-89821-73-6 (ISBN)
Merknad

Bakom projektet står ett stort antal gjuteriföretag och det statliga forskningsinstitutet RISE. Det pågår 2020-2023 och finansieras av Svenska Gjuteriföreningen och det strategiska innovationsprogrammet Metalliska material, en gemensam satsning av Vinnova, Energimyndigheten och Formas.

Tilgjengelig fra: 2023-10-30 Laget: 2023-10-30 Sist oppdatert: 2024-05-17bibliografisk kontrollert
Räftegård, O. (2023). GRETA Energieffektiv processventilation.
Åpne denne publikasjonen i ny fane eller vindu >>GRETA Energieffektiv processventilation
2023 (svensk)Rapport (Annet vitenskapelig)
Abstract [en]

GRETA energy efficient process ventilation

The report gives examples of measures and of the underlying theory to make process ventilation more electrically efficient in two Swedish foundries. The savings for the two studied process ventilation systems are about 90% for a steel foundry and about 20% for an iron foundry. This corresponds to about 600,000 kWh/year electricity and 200,000 kWh/year, respectively. With an assumed electricity price of 1 SEK/kWh, this amounts to SEK 600,000/year and SEK 200,000/year respectively. In both cases, the measures consist of adapting air flows to the operating case by regulating the fan using a frequency converter. The theory section shows that the distance between the source of the pollution and the exhaust has a very large impact on electricity for fan operation, but that other measures besides reducing the distance are also important. Suggestions for practical methods to tune process exhausts include the use of smoke flares that provide a clear visual response to capture capability before and after a change.

Publisher
s. 18
Serie
RISE Rapport ; 2023:99
Emneord
foundry, process ventilation
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-67573 (URN)978-91-89821-77-4 (ISBN)
Merknad

Bakom projektet står ett stort antal gjuteriföretag och det statliga forskningsinstitutet RISE. Det pågår 2020-2023 och finansieras av Svenska Gjuteriföreningen och det strategiska innovationsprogrammet Metalliska material, en gemensam satsning av Vinnova, Energimyndigheten och Formas.

Tilgjengelig fra: 2023-10-30 Laget: 2023-10-30 Sist oppdatert: 2024-05-17bibliografisk kontrollert
Hamon, C., Abdollahi, E., Dahl, J. & Räftegård, O. (2023). Sector coupling of district heating with the electricity system: profitability and operations (SeCoHeat). RISE Research Institutes of Sweden
Åpne denne publikasjonen i ny fane eller vindu >>Sector coupling of district heating with the electricity system: profitability and operations (SeCoHeat)
2023 (engelsk)Rapport (Annet vitenskapelig)
Abstract [en]

District heating systems can play key roles in the energy transition. The transition to a production mix based on renewable intermittent generation will create a larger need for ancillary services including frequency-regulation services. District heating systems typically participate in the wholesale electricity market (the so-called day-ahead market) today but do not, in general, participate in ancillary service markets. Previous studies have shown that it is technically possible to participate in these markets and that district heating systems have a role to play in these markets in the future. This requires investigating how further integration of district heating systems with the electrical grids and markets will impact operation and planning of these units. In addition, while it may be beneficial on a system level for district heating systems to participate in ancillary service markets, district heating system owners and operators will only do so if there are economic incentives to do so. The SeCoHeat project has therefore explored topics related to the profitability for individual district heating systems to participate in other electricity markets than just the day-ahead market, such as ancillary service markets. Studying sector coupling between the heat and electricity systems requires a thorough understanding of both sectors. This project has contributed to this by bringing together experts from both sides which has led to fruitful knowledge exchanges. Furthermore, some deliverables from the SeCoHeat project have been especially written to provide introduction about the heat sector to experts from the electricity sector, and vice versa. This includes an overview of the electricity markets in which district heating systems can participate, the technical requirements to participate in these markets and explanations about how profitability of participating in these markets can be computed. This also includes explanations about how the flexibility on the heat side can be sourced and provided to the electricity system and what limits this flexibility. Another important contribution of this project is the development of a Python-based open model for scheduling district system units on an hourly basis to minimize heat and electricity production costs while maximising revenues from several electricity markets. This model has been used in this project to evaluate the additional profits of participating in ancillary service markets. The results show that substantial additional profits can be made by doing so, both in historical years and in scenarios for future years. This report is a guide to the separate deliverables produced within this project. It offers an overview of the goals, methods and results from the project. The interested reader is referred to detailed descriptions in the corresponding deliverables. The SeCoHeat project was funded by Göteborg Energi AB:s stiftelse för forskning och utveckling. The work has been performed by RISE with the support of reference group members from Göteborg Energi, Vattenfall, Svenska kraftnät, IVL Svenska Miljöinstitutet, Chalmers and Profu.

sted, utgiver, år, opplag, sider
RISE Research Institutes of Sweden, 2023
Serie
RISE Rapport ; 2023:89
Emneord
Sector-coupling, district heating, ancillary services
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-73123 (URN)978-91-89821-62-0 (ISBN)
Tilgjengelig fra: 2024-05-13 Laget: 2024-05-13 Sist oppdatert: 2024-05-17bibliografisk kontrollert
Wallin, E., Fornell, R., Räftegård, O., Walfridson, T. & Benson, J. (2020). Design and integration of heat recovery in combination with solar and biomass-based heating in a drying plant. Chemical Engineering Transactions, 81, 1387-1392
Åpne denne publikasjonen i ny fane eller vindu >>Design and integration of heat recovery in combination with solar and biomass-based heating in a drying plant
Vise andre…
2020 (engelsk)Inngår i: Chemical Engineering Transactions, ISSN 1974-9791, E-ISSN 2283-9216, Vol. 81, s. 1387-1392Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The EU27 annually generates 90 Mt of food waste, and approximately 40 % of this waste is generated during manufacturing. The food processing industry needs to develop improved and sustainable solutions for waste valorisation and re-use. The project DRALOD addresses this issue since it aims at design, integration and assessment of the performance of a heat recovery system in connection with an innovative low-temperature air drying unit where high moisture food waste is dewatered and sold as a by-product with preserved nutritional ingredients. The air used for drying is preheated using solar heat and a biomass boiler, and in this project the potential benefits of integration of a heat recovery system have been investigated. Due to the impurities available in the humid exhaust air from the dryer, the heat recovery is designed with two principal systems; a wet scrubber condensation system and a heat pump system. Simulations using hourly meteorological data from Madrid have been made for the total system with heat recovery, and the generated results have been used as inputs in a techno-economic analysis in order to assess the integration of the heat recovery and how sensitive different economic parameters and assumptions are for the results. It can be concluded from the assessment that the prices of electricity and biofuel will have a high impact on the economic performance and design. For the integration of the heat recovery system to be economically justifiable it is estimated, given assumptions made in this analysis, that the electricity cost needs to be less than 5 times higher than the biofuel cost. 

sted, utgiver, år, opplag, sider
Italian Association of Chemical Engineering - AIDIC, 2020
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-49480 (URN)10.3303/CET2081232 (DOI)2-s2.0-85092045401 (Scopus ID)
Merknad

Funding details: European Commission, EC; Funding details: Horizon 2020, 820554; Funding text 1: This research has been supported by the EU project “Fast Track to Innovation - FTI”, DRALOD is co-funded by the European Commission - Horizon 2020 Programme - under Grant Agreement 820554. The DRALOD project is a collaboration between PERNIA, DBFZ, ÖKOTHERM and RISE. For more information about DRALOD please visit dralod.com.

Tilgjengelig fra: 2020-10-16 Laget: 2020-10-16 Sist oppdatert: 2024-05-17bibliografisk kontrollert
Lindahl, M., Walfridson, T., Benson, J., Räftegård, O., Gustafsson, O. & Haglund Stignor, C. (2020). Possibilities and constraints of grid flexible control of todays and tomorrows heat pumps. In: 13th IEA Heat Pump Conference.: . Paper presented at 13th IEA Heat Pump Conference. May 11-14, 2020 Jeju, Korea.
Åpne denne publikasjonen i ny fane eller vindu >>Possibilities and constraints of grid flexible control of todays and tomorrows heat pumps
Vise andre…
2020 (engelsk)Inngår i: 13th IEA Heat Pump Conference., 2020Konferansepaper, Publicerat paper (Fagfellevurdert)
Abstract [en]

In this article possibilities and constraints of grid flexible control of heat pumps for domestic heating are investigated. By creating dynamic coalitions of heat pumps and control their power consumption, demand response can be offered to the power grid. For a functional power grid, the heat pumps electrical power consumption needs to follow the electrical grids needs accurately. Possibilities to externally control the power consumption of a ground source heat pump has been investigated. Both direct control, where the compressor speed is set directly, and indirect control, achieved with outdoor temperature sensor override, has been evaluated. For the evaluation a test cycle for laboratory testing of a heat pumps grid flexibility has been developed. Based on the test cycle, the heat pumps possibilities to follow the load profile using both direct and indirect control was tested in laboratory. Both control methods were possible to use, with the direct control being significantly more accurate. Using direct control, the power consumption of the compressor managed to be within ±10% of the stated power consumption for 97% of the time.

Emneord
Grid flexible heat pump; Heat Pump control; Smart grid; Demand response; Heat Pump
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-56326 (URN)
Konferanse
13th IEA Heat Pump Conference. May 11-14, 2020 Jeju, Korea
Tilgjengelig fra: 2021-09-06 Laget: 2021-09-06 Sist oppdatert: 2024-05-17bibliografisk kontrollert
Hennessy, J., Li, H., Wallin, F., Thorin, E. & Räftegård, O. (2017). Economic feasibility of commercial heat-to-power technologies suitable for use in district heating networks. Paper presented at 9th International Conference on Applied Energy, ICAE 2017, 21 August 2017 through 24 August 2017. Energy Procedia, 1721-1727
Åpne denne publikasjonen i ny fane eller vindu >>Economic feasibility of commercial heat-to-power technologies suitable for use in district heating networks
Vise andre…
2017 (engelsk)Inngår i: Energy Procedia, ISSN 1876-6102, s. 1721-1727Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Recent improvements in heat-to-power (HtP) technologies have led to an increase in efficiency at lower temperatures and lower cost. HtP is used extensively in power generation via the steam Rankine cycle, but so far has not been used in district heating (DH). The aim of the study is to analyze the economic feasibility of using HtP technologies in a DH network. This is achieved by establishing suitable technologies and calculating the levelized cost of electricity (LCOE) under conditions that may be found in DH. The result, for the vendors, temperatures and assumptions considered, is a range of 25-292 €/MWh, excluding the cost of heat. The breadth of this range in part reflects the importance of selecting appropriate products to match the heat source temperature.

Emneord
ancillary services, balancing power, district energy, district heat to power, district heating, heat to power, LCOE, LCOH, levelized cost of electricity, levelized cost of heat, ORC, organic Rankine cycle, smart grids, smart thermal grids, thermal grids
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-33325 (URN)10.1016/j.egypro.2017.12.555 (DOI)2-s2.0-85041516921 (Scopus ID)
Konferanse
9th International Conference on Applied Energy, ICAE 2017, 21 August 2017 through 24 August 2017
Merknad

Funding details: KK, Stiftelsen för Kunskaps- och Kompetensutveckling; Funding details: Knowledge Foundation; Funding details: AIR, American Institutes for Research; Funding text: Special thanks to the participating vendors for their detailed data provided in confidence. The work has been carried out under the auspices of the Reesbe industrial post-graduate school, which is financed by the Knowledge Foundation (KK-stiftelsen), Sweden . The work was also part-financed by RISE Research Institutes of Sweden.

Tilgjengelig fra: 2018-02-27 Laget: 2018-02-27 Sist oppdatert: 2024-05-17bibliografisk kontrollert
Organisasjoner
Identifikatorer
ORCID-id: ORCID iD iconorcid.org/0009-0001-5256-3708
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