412 research outputs found
A radial model for fast analysis of thermal pile heat exchangers
No full textEnergy piles offer an effective way to decarbonise heating and cooling via exchange of heat through the deep foundations of a building or other structure. However, efficient analysis methods are required to allow energy performance to be determined in a way compatible with building energy design and energy system design approaches. We test a fast run time analytical model (the Claesson-Javed radial model) that retains a physical basis linked to the energy pile geometry, while making simplifications to permit a radial approximation to be used. We also present validation G-functions from the model development processes that have been derived from 2D and 3D numerical simulation.</span
Evaluating the applicability of the radial approximation for pile heat exchangers
No full textThis paper appraises the efficacy of using an analytical radial approximation for different thermal pile heat exchanger geometries. Unsteady radial heat-flow from fluid in a pipe set within a grouted borehole into the external ground is well-documented and can be solved analytically very rapidly using Laplace Transforms (Javed and Claesson 2011). By comparing the radial model with finite-element simulations including explicit pile geometries, this paper provides a provisional analysis of the accuracy of this approach. Initial findings suggest that the radial model may provide an appropriate approximation to pile behaviour for certain pipe configurations, albeit with small ‘mid-time’ error
Optimal distribution of thermal insulation and ground heat losses /Johan Claesson, Bengt Eftring
No full textHeat extraction from the ground by horizontal pipes :a mathematical analysis /Johan Claesson, Alain Dunand
No full textA fast approximate method for simulating thermal pile heat exchangers
No full textGround source heat pump systems, operating in conjunction with vertical ground heat exchangers, will play a key role in decarbonising heating and cooling of buildings. Design of traditional borehole heat exchangers relies on tools which implement routine analytical relationships between heat transferred and the temperature change in the ground and circulating thermal fluid. However, for novel piled foundations used as ground heat exchangers, there are few such analytical solutions available that are practical for routine implementation. This paper examines the use of a radial approximation to simulate the dynamic thermal behaviour of pile heat-exchangers. Originally developed for small diameter and high aspect ratio borehole heat exchangers, the approach is more challenging for piles since unsteady heat transfer within the pile material is more significant over typical timescales. Nonetheless, we demonstrate that for pile diameters between 300 mm and 1200 mm, generally the error is <1 °C with centrally placed heat transfer pipes or four or more pipes placed near the edge with circumferential spacing less than 550 mm. The radial model is therefore practical for most pile configurations. The strong performance of the model is demonstrated for a year of hypothetical heating and cooling cycles, and also against a field-scale thermal response test
Unio mystica III
No full textMusik av Carl-Axel Hall
Videoverk av Petra Johansson, Neta Norrmo och Sarah Schmidt.
Medverkande: Nina Åkerblom Nielsen - flöjt
Anders Jonhäll - flöjt
Urban Claesson - klarinett
Philip Foster - valthorn
Malvakvartetten: Brita Pettersson, Linnea Hällqvist , Maria Jonsson, Stina Larsdotter
Ahmad al-Khatib - oud
Carl-Axel Hall, Fredrik Duvling, Johan Renman - slagverk
Andreas Hall - saxofon
Dirigent: Johannes Landgren
Medverkande
Nina Åkerblom Nielsen - sång
Anders Jonhäll - flöjt
Urban Claesson - klarinett
Philip Foster - valthorn
Malvakvartetten: Brita Pettersson, Linnea Hällqvist - violin, Maria Jonsson - viola, Stina Larsdotter - cello
Ahmad al-Khatib - oud
Carl-Axel Hall, Magnus Ricklund - piano
Daniel Berg, Fredrik Duvling, Johan Renman - slagverk
Andreas Hall - saxofon
Dirgent: Johannes Landgre
How the Pressure Build-Up Affects the Penetration Length of Grout-New Formulation of Radial Flow of Grout Incorporating Variable Pressure
No full textFor around two decades of research and development in the field of grouting in hard jointed rock, the design process has taken some leaps forward. Stille and Gustafson, 2005 and Funehag and Gustafson 2008, shows how a grouting design can be computed. A grouting design in hard rock can based on the penetration length of grout in rock fractures. The design comprises considerations of the fracture apertures in the rock mass, the type of grout and its rheological properties and how the grout is injected i.e pressure and grouting times. When knowing these parameters an optimized geometry fitting the design is made. Thörn, et al, 2014 describes a fundamental analysis with a comprehensive tool to retrieve the fracture distribution and aperture distribution of the fractures crossing a cored borehole. The data needed about the core is geological mapping and hydraulic section tests. In Gustafson, Claesson and Fransson, (2013) a full derivation of a radial Bingham flow in a slit is described for constant pressure. By optimizing with a specific pressure and an efficient grouting time (efficient time means the time when the pressure has reached the designed pressure) a prognosis a more realistic time consumption for grouting can be computed. However, the time it takes to reach a certain pressure is dependent on the capacity of the pump and the how large the fractures widths are. For poorly chosen pumps together with large fractures the time to reach the design pressure can be significant. The overall objective for this new formulation was to involve the grouting pressure as a variable rather than constant. A pressure build-up mimic more a realistic pumping scenario which enables better prognosis of grouting works. This paper brings up this new formulation of the radial Bingham flow with variable injection pressure in slit. The benefits of this new formulation is that it can easily be integrated in other computer programs. One program that uses this new formulation is a grouting simulator owned and developed by Edvirt AB. The simulator has been used to pedagogically demonstrate how a variable pressure and restrictions in grout flow (the pump capacity) affect the penetration length. Further, the results show that it can be used to predict suitable pump capacity to fit the coming grouting works
Dissertatio juridica, de mercatura, qvam ex censura amplissimae facult. juridicae in Regia Acad. Aboensi, sub praesidio ... dn. Mattiae Swederi, jur. patr. & Rom. profess. ordinarii, in auditorio majori, ad diem XXXI Maij anni M DC LXXXX. publico bonorum examini modeste subjicit Andreas Råberg Westro-Gothus.
No full textVariantti A.Invokaatio: Q.F.F.Q.S.Dedikaatio: Gustavus Adolphus de la Gardie, Samuel Åkerhielm, Nicolaus von Preutz, Jonas Rudberus, Johan Pederson.Esipuhe.Gratulaatio: Matthias Swederus, Dan. Achrelius, David Lund, Sveno Dimberg, Carl Iean Delamotte, Claudius Vggla, Jacob. Wännergreen.Painovuosi nimekkeestä.Arkit: )(4, A-C4 D2 E4
Tales of Foresight : En kvalitativ studie om berättelser kring futuristers arbetsmetoder
No full textTitel: Tales of Foresight – En kvalitativ studie om berättelser kring futuristers arbetsmetoder Nivå: Avancerad, Magister Författare: Christoffer Axell, Jonas Claesson (87/05/09) (95/01/12) Handledare: Klara Regnö Examinator: Johan Grindbergs Datum: 2020-06-03 Insitution: Akademin för Ekonomi, Samhälle och Teknik, Mälardalens Högskola Syfte: Syftet med studien är att skapa en djupare förståelse för hur futurister beskriver sina arbetsmetoder inom framtidsstudier. Frågeställning: Vilka berättelser använder futurister sig av när de förklarar sina arbetsbetsmetoder? Kan berättelser skapa meningsfullhet om framtidsstudier och framtidsfrågor? Metod: Kvalitativ studie med fokus på intervjuer, tematisk innehållsanalys, narrativ ansats, tolkningsverktyg: Casual Layered Analysis modellen Slutsats: Studien samlade in berättelser från futurister uti praktiken och identifierade 32 berättelser och metaforer som förklara deras beskrivningar av arbetsmetoder inom framtidsstudier och framtidsfrågor. Insamlingen av berättelser och metaforer skapar en djupare karaktäristisk bild av futuristers arbetsmetoder om framtidsstudier och minskar därmed klyftan mellan prognoser om framtid och att kunna handla utifrån dessa. Utöver detta bidrar studien med att minskat kunskapsluckorna inom framtidsstudier genom att kombinera framtidsstudier, storytelling och sensemaking för att undersöka hur deltagarna skapar meningsfullhet inom framtidsstudier. Nyckelord: Framtidsstudier, Storytelling, Sensemaking, Narrativa Framtidsstudier, Causual Layered Analysis modelle
Tilläggsisolering - lönsamt enligt en livscykelkostnadsmodell?
No full textIt is found that the properties of the record years of 1965-1975 is leaking a lot of energy and these properties are facing a major energy efficiency. From the energy aspect, the facade is afflicted with poor thermal insulation which is a big problem. To address this problem adding insulation is a good alternative to reduce overall energy consumption of a building. The windows on these buildings are also a problem from the energy point of view. Therefore, there are many reasons considered for energy upgrading. These types of investments are often associated with a very high initial investment, however, investment decision is also based in the savings that could be the result of the operation. With this as background the authors of this paper is questioning whether it is viable to energy upgrade by additional insulation compared to not make any energy upgrade at all of the properties built during the record years. The purpose of this paper is to describe the energy problems that exist with two types of wallconstructions that were common during the record years and the financial impact these problems resulting. By examining the costs, adding insulation the essay will through a life cycle cost show which action that is most profitable. The authors of this paper have conducted a case study of two wallconstructions of the types curtain walls and concrete. The thesis began by contacting Sto Scandinavia AB, which is a company that produces facade constructions and insulationsystems. Through interview with Claes Göran Claesson (Product Object Manager) on Sto Scandinavia, all pricing information by adding insulation could be identified. Contact was also made with energy expert Per Karnehed who assisted with the energy analysis of two properties which form the basis for the calculations in this paper. Using this information a life-cycle cost was calculated with the result that the insulation of the wallconstructions were viable over a 50 year period. The crucial factor in this calculation was the price of energy and futue cost of this. The calculations presented in this paper clearly shows in the long run that the energy cost is the largest post, not the initial investment.Det är konstaterat att fastigheter från rekordåren 1965-1975 läcker mycket energi och dessa fastigheter står inför en omfattande energieffektivisering. Ur energisynpunkt är det ytterväggarnas bristfälliga värmeisoleringsförmåga som är det stora problemet. För att åtgärda detta problem är tilläggsisolering ett bra alternativ för att få ner den totala energiförbrukningen för en fastighet. Fastigheternas fönster är också ett problem rent energimässigt. Därför finns det många anledningar till att även dessa behöver en energiuppgradering. Dessa typer av investeringar förknippas ofta med en väldigt hög grundinvestering, dock måste investeringsbeslut även grunda sig i vilka framtida besparingar som kan göras till följd av åtgärden. Med detta som bakgrund ställer sig författarna till denna uppsats frågan om det är lönsamt att energiuppgradera fastigheter genom att tilläggsisolera jämfört med att inte utföra någon energiuppgradering alls hos de fastigheter som är uppförda under miljonprogrammet. Syftet med denna uppsats är att beskriva vilka energiproblem det finns med två typiska ytterväggskonstruktioner som var vanliga under miljonprogramsåren och vilka ekonomiska konsekvenser dessa problem medför. Genom att undersöka de kostnader som en tilläggsisolering för med sig kommer uppsatsen med hjälp av en livscykelkostnad förklara vilken åtgärd som är mest lönsam. Författarna har utfört en fallstudie på två ytterväggskonstruktioner av typ utfackningsvägg och lättbetong. Uppsatsarbetet började med att kontakt togs med Sto Scandinavia AB som bland annat levererar produkter inom tilläggsisolering. Genom intervjuer med Claes Göran Claesson (Product Object Manager) på Sto Scandinavia kunde all prisinformation angående tilläggsisolering kartläggas. Kontakt togs även med energiexperten Per Karnehed som bistod med energianalyser på två fastigheter som ligger till grund för beräkningarna i denna uppsats. Med hjälp av denna information kunde en livscykelkostnad beräknas med resultatet att tilläggsisolering av dessa ytterväggskonstruktioner var lönsamt under en 50 års period. Den avgörande faktorn i denna kalkyl blev energipriset och framförallt prisutvecklingen av denna. Kalkylerna som presenteras i denna uppsats visar tydligt på att det inte är grundinvesteringen som är den största kostnaden på lång sikt utan energikostnaderna
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