| 1. |
- Gustafsson, Mattias, 1972-
(författare)
-
Evaluation of energy conserving measures in buildings connected to a district heating system : case studies in Gävle, Sweden
- 2016
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- When different energy conserving measures are implemented for reducing energy use in buildings and the buildings are connected to district heating systems, it is important that an overall system analysis is made which takes into account the effects of total change of energy use due to the energy conserving measures.The method applied in this thesis uses hourly production data for the different production units in the district heating system in Gävle, Sweden. The merit order of the different production units is dependent on the electricity spot market price. To calculate the merit order, hourly data for the electricity price is used. The marginal production unit can then be determined for each hour of the investigated year.This thesis analyzes five different energy conserving measures in a multi-dwelling building regarding how they affect the marginal production units in the district heating system. For CO2 emission evaluations, two different combinations of heat and electricity conserving measures are compared to installation of an exhaust air heat pump. This thesis also analyzes how the configuration of the electric meter affects the measured amount of self-consumed and produced excess electricity for a single-family house and for two multi-dwelling buildings of different sizes.The results show that the use of electricity is the most important objective to consider. The increased use of electricity for operation of the heat pump contributes to an increase of global CO2 emissions and the electricity produced by the solar photovoltaic installation contributes to a decrease of global CO2 emissions.The results also show that the configuration of the electric meter is important for the single-family house but negligible for the multi-dwelling buildings. The amount of produced excess electricity is high for all buildings, which means that the economic value of produced excess electricity is important for a profitable installation.
|
|
| 2. |
- Karlsson, Magnus, et al.
(författare)
-
Regional energy system optimization - Potential for a regional heat market
- 2009
-
Ingår i: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 86:4, s. 441-451
-
Tidskriftsartikel (refereegranskat)abstract
- Energy supply companies and industrial plants are likely to face new situations due to, for example, the introduction of new energy legislation, increased fuel prices and increased environmental awareness. These new prerequisites provide companies with new challenges but also new possibilities from which to benefit. Increased energy efficiency within companies and increased cooperation between different operators are two alternatives to meet the new conditions. A region characterized by a high density of energy-intensive processes is used in this study to find the economic potential of connecting three industrial plants and four energy companies, within three local district heating systems, to a regional heat market, in which different operators provide heat to a joint district heating grid. Also, different investment alternatives are studied. The results show that the economical potential for a heat market amounts to between 5 and 26 million EUR/year with payback times ranging from two to eleven years. However, the investment costs and the net benefit for the total system need to be allotted to the different operators, as they benefit economically to different extents from the introduction of a heat market. It is also shown that the emissions of CO2 from the joint system would decrease compared to separate operation of the systems. However, the valuation of CO2 emissions from electricity production is important as the difference of emitted CO2 between the accounting methods exceeds 650 kton/year for some scenarios.
|
|
| 3. |
- Klugman, Sofia, et al.
(författare)
-
A Scandinavian chemical wood-pulp mill : Part 1. Energy audit aiming at efficiency measures
- 2007
-
Ingår i: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 84:3, s. 326-339
-
Tidskriftsartikel (refereegranskat)abstract
- A Swedish wood-pulp mill is surveyed in terms of energy supply and use in order to determine the energy-saving potential. Conservation measures are of increasing interest to Swedish industry, as energy prices have continued to rise in recent years. The electricity price particularly increased after the deregulation of the Scandinavian electricity market in 1996. The deregulation expanded to all of the EU in July 2004, which may increase the Swedish electricity price further until it reaches the generally higher European price level. Furthermore, oil prices have increased and the emissions trading scheme for CO2 adds to the incentive to reduce oil consumption. The energy system at the surveyed pulp mill is described in terms of electricity and process heat production and use. The total energy-saving potential is estimated and some saving points are identified. The heat that today is wasted at the mill has been surveyed in order to find potential for heat integration or heat export. The result shows that the mill probably could become self-sufficient in electricity. Particularly important in that endeavor is updating old pumps.
|
|
| 4. |
- Klugman, Sofia, et al.
(författare)
-
A Scandinavian chemical wood-pulp mill : Part 2. International and model mills comparison
- 2007
-
Ingår i: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 84:3, s. 340-350
-
Tidskriftsartikel (refereegranskat)abstract
- The energy use at a Swedish chemical wood-pulp mill is compared internationally and for two model mills that aim to use the most efficient available technology. The international comparison is performed between Canadian and Scandinavian pulp-mills on a general level, and on a closer level among eleven Swedish and Finnish non-integrated sulfate pulp-mills, the type of mill considered in the case study. The two model mills that are used for comparison are one Swedish and one Canadian. The Scandinavian pulp-mills are somewhat more energy efficient than the Canadian mills. Still, the variation in energy use is remarkably large among the Scandinavian mills, which indicates that the energy-saving potential is great. If all Swedish freestanding sulfate pulp-mills became as energy efficient as the most efficient Scandinavian mill, electricity savings corresponding to nearly 1% of the national electricity use would be obtained. In the model mills comparison it was found that large amounts of heat could be saved, particularly in the evaporation plant.
|
|
| 5. |
- Klugman, Sofia, et al.
(författare)
-
A Swedish integrated pulp and paper mill - Energy optimisation and local heat cooperation
- 2009
-
Ingår i: Energy Policy. - : Elsevier BV. - 0301-4215 .- 1873-6777. ; 37:7, s. 2514-2524
-
Tidskriftsartikel (refereegranskat)abstract
- Heat cooperation between industries and district heating companies is often economically and environmentally beneficial. In this paper, energy cooperation between an integrated Swedish pulp and paper mill and two nearby energy companies was analysed through economic optimisations. The synergies of cooperation were evaluated through optimisations with different system perspectives. Three changes of the energy system and combinations of them were analysed. The changes were process integration, extending biofuel boiler and turbine capacity and connection to a local heat market. The results show that the single most promising system change is extending biofuel and turbine capacity. Process integration within the pulp and paper mill would take place through installing evaporation units that yield less excess heat but must in this particular case be combined with extended biofuel combustion capacity in order to be beneficial. Connecting to the local heat market would be beneficial for the pulp and paper mill, while the studied energy company needs to extend its biofuel capacity in order to benefit from the local heat market. Furthermore, the potential of reducing CO2 emissions through the energy cooperation is shown to be extensive; particularly if biofuel and turbine capacity is increased.
|
|
| 6. |
- Klugman, Sofia, et al.
(författare)
-
An integrated chemical pulp and paper mill : energy audit and perspectives on regional cooperation
- 2006
-
Ingår i: ECOS 2006. - 9608758416 ; , s. 637-644
-
Konferensbidrag (populärvet., debatt m.m.)abstract
- As a case study, an energy audit was performed at an integrated pulp and paper mill. A top-down approach was applied to identify and categorize the use of electricity, steam and hot water and the results of the audit are presented in this paper. Also, the connections and cooperation with both the nearby district heating system and a local steam deliverer, partly owned by the mill, are described. Potential ways to save energy are pointed out and changes in the cooperation are discussed. Moreover, a discussion of how the system can benefit from the taxation structure is presented, as the design of the studied system, in combination with the introduction of tradable green certificates, creates possibilities to exploit such benefits. As a result from this design it is shown that the introduction of these certificates promotes the use of oil to produce electricity.
|
|
| 7. |
- Klugman, Sofia, et al.
(författare)
-
Modeling an industrial energy system : Perspectives on regional heat cooperation
- 2008
-
Ingår i: International Journal of Energy Research. - Chichester, West Sussex, United Kingdom : John Wiley & Sons. - 0363-907X .- 1099-114X. ; 32:9, s. 793-807
-
Tidskriftsartikel (refereegranskat)abstract
- Through energy efficiency measures, it is possible to reduce heat surplus in the pulp and paper industry. Yet pulp and paper mills situated in countries with a heat demand for residential and commercial buildings for the major part of the year are potential heat suppliers. However, striving to utilize the heat within the mills for efficient energy use could conflict with the delivery of excess heat to a district heating system. As part of a project to optimize a regional energy system, a sulfate pulp mill situated in central Sweden is analyzed, focusing on providing heat and electricity to the mill and its surrounding energy systems. An energy system optimization method based on mixed integer linear programming is used for studying energy system measures on an aggregated level. An extended system, where the mill is integrated in a regional heat market (HM), is evaluated in parallel with the present system. The use of either hot sewage or a heat pump for heat deliveries is analyzed along with process integration measures. The benefits of adding a condensing unit to the back-pressure steam turbine are also investigated. The results show that the use of hot sewage or a heat pump for heat deliveries is beneficial only in combination with extended heat deliveries to an HM. Process integration measures are beneficial and even increase the benefit of selling more heat for district heating. Adding a condensing turbine unit is most beneficial in combination with extended heat deliveries and process integration.
|
|
| 8. |
- Kylemark, Per, et al.
(författare)
-
Noise statistics in fiber optical parametric amplifiers
- 2007
-
Ingår i: Journal of Lightwave Technology. - 0733-8724 .- 1558-2213. ; 25:2, s. 612-620
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, we show both theoretically and experimentally that the probability density function of the intensity of an amplified signal by parametric amplifiers subject to a pump with excess noise is highly asymmetric. This is due to the nonlinear relationship between the optical pump power and the parametric gain. Because of this, the relationship between the noise figure (NF) and the bit error rate (BER) is modified, compared with that predicted by the chi(2) theory, which is an effect that is notable at large NFs and low BERs. The difference in predicted BER can be of several orders of magnitudes between the correct theory and the chi(2) approximation in single-stage parametric amplifiers. We also show that in the limit of many cascaded parametric amplifiers, the statistics of the noise of an amplified optical signal approaches chi(2). Furthermore, the BER of a parametric amplifier is generally lower compared with erbium-doped fiber amplifiers for the same NF values if we assume quantum-limited amplification.
|
|
| 9. |
- Mardan, Nawzad, 1965-
(författare)
-
Combining simulation and optimization for improved decision support on energy efficiency in industry
- 2012
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Industrial production systems in general are very complex and there is a need for decision support regarding management of the daily production as well as regarding investments to increase energy efficiency and to decrease environmental effects and overall costs. Simulation of industrial production as well as energy systems optimization may be used in such complex decision-making situations.The simulation tool is most powerful when used for design and analysis of complex production processes. This tool can give very detailed information about how the system operates, for example, information about the disturbances that occur in the system, such as lack of raw materials, blockages or stoppages on a production line. Furthermore, it can also be used to identify bottlenecks to indicate where work in process, material, and information are being delayed.The energy systems optimization tool can provide the company management additional information for the type of investment studied. The tool is able to obtain more basic data for decision-making and thus also additional information for the production-related investment being studied. The use of the energy systems optimization tool as investment decision support when considering strategic investments for an industry with complex interactions between different production units seems greatly needed. If not adopted and used, the industry may face a risk of costly reinvestments.Although these decision-making tools individually give good results, the possibility to use them in combination increases the reliability of the results, enhances the possibility to find optimal solutions, promises improved analyses, and a better basis for decisions in industry. The energy systems optimization tool can be used to find the optimal result and the simulation tool can be used to find out whether the solution from the optimization tool is possible to run at the site.In this thesis, the discrete event simulation and energy systems optimization tools have been combined. Three Swedish industrial case studies are included: The new foundry at Volvo Powertrain in Skövde, Arla Foods dairy in Linköping and the SKF foundry in Katrineholm. Results from these cases show possibilities to decrease energy use and idling, to increase production, to combine existing and new production equipment and to decrease loss of products.For an existing industrial system, it is always preferable to start with the optimization tool reMIND rather than the simulation tool – since it takes less time to build the optimization model and obtain results than it does to build the corresponding simulation modeling. While, for a non-existent system, it is in general a good idea to use both the simulation and the optimization tool reMIND simultaneously, because there are many uncertain data that are difficult to estimate, by using only one of them. An iterative working process may follow where both tools are used.There is a need for future work to further develop structured working processes and to improve the model to e.g. take production related support processes into account. To adapt the results in industries, improve the user friendliness of the tool and the understanding of the underlying modeling developments of the optimization tool reMIND will be necessary.
|
|
| 10. |
- Mattsson, Magnus, 1964-, et al.
(författare)
-
Fältstudie av två metoder för energieffektivisering av äldre fönster – fönsterfilmer testade med hotbox-teknik
- 2020
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Föreliggande studie har undersökt två typer av fönsterfilmer som avser förbättra fönster avseende energi- och komfortaspekter. Filmerna utgörs av tunn självhäftande plast med högteknologisk strålningsreflekterande beläggning. Framför allt har en ny typ av värmeisolerande film (här kallad ”Energifilm”) testats, vilken främst syftar till att minska värmeförlusten genom fönstret mot ett kallare uteklimat. Energifilmen har i detta projekt provats i fält med den s.k. hotbox-metoden, varvid ett 2-glasfönsters värmeförlust kunnat mätas på plats i en verklig, kulturhistorisk byggnad – Rådhuset i Gävle. Hotbox-metoden används normalt i laboratoriemiljö och ett viktigt syfte med projektet har varit att utvärdera metoden i fält. Förutom energifilmen provades även solreflekterande film (”Solfilm”), vilken främst avser minska transmission av strålningsvärme från direkt solljus. Studien innefattar även antikvariska och estetiska aspekter på applicering av fönsterfilmer, där byggnadsantikvarier anlitats för subjektiv bedömning. Resultaten pekar på att hotbox-metoden är användbar i fält, om än ganska mödosam att få på plats rent praktiskt. Mätresultaten indikerar att montage av Energifilm minskar värmetransporten (U-värdet) genom fönstrets glasade del med ca 31 % om filmen placeras på någon av glasytorna i spalten mellan glasen, medan minskningen blir ca 19 % vid placering på insidan av innerglaset. Placering i spalten tycks därmed effektivast när så är möjligt; det minskar också risken för kondens och kallras längs fönstrets insida. Rent ekonomiskt tycks det emellertid svårt att räkna hem någon vinst genom investering i vare sig Energifilm eller Solfilm. Montage av Solfilm tenderar tvärtom att öka energikostnaderna. Termisk buffring i den tunga rådhusbyggnaden bidrar till att hålla nere den värmeökning som kan ske vid mycket solinstrålning och internvärme; Solfilm torde komma bättre till pass i lättare byggnader. Rådhusbyggnaden var även försedd med mekanisk behovsstyrd ventilation, med möjlighet till ganska höga ventilationsflöden för kylning; i byggnader utan sådant system kommer Solfilm till bättre nytta. Både energi- och Solfilm förbättrar dock den termiska komforten, både avseende kyla och värme, särskilt för personer som befinner sig i närheten av fönstren. Så, snarare än minskade kostnader torde det vara komfort- och/eller miljöskäl som kan motivera investering i fönsterfilmerna. Fönsterfilmerna medförde minskad ljustransmittans (-16 % för Energifilm; -22 % för Solfilm) och viss (måttlig) färgförändring vid vissa ljusförhållanden och betraktelsevinklar. Överlag fick de studerade fönsterfilmerna emellertid tämligen hög acceptans av byggnadsantikvarierna, men man noterade att noggrannhet vid montaget är mycket viktigt. Montage av filmerna demonstrerades också gå förhållandevis snabbt och medföra liten störning på verksamheten i lokalerna under installation. Filmerna kan också klippas till att passa t.ex. krökta bågar, och de medför inte någon ökad belastning (tyngd) för fönstret, i jämförelse med andra metoder som innebär komplettering med ett extra glas på bågen. Test av borttagning av 3 år gammal Energifilm visade att detta kunde göras utan att skada fönster-glasen, men det synes tveksamt att montera filmerna på riktigt tunna, ömtåliga glas, då sådana riskerar gå sönder vid borttagning av filmen, som ändå noterades sitta tämligen hårt fast.
|
|
