| 1. |
- Bellander, Rickard, et al.
(författare)
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Durability of outdoor exposed wood : a comparative study on a noise barrier
- 2003
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Annan publikation (populärvet., debatt m.m.)abstract
- In March 1996 nine test sections of a noise barrier were built along the Arlandaline in co-operation with Banverket, Royal Institute of Technology (KTH), Swedish National Testing Research Institute (SP), Beijer Bygg AB and different wood preservative manufactures. Each sections has an approximately length of 4 meters per section and a height of 3,1 meter. Three sections are made of non-treated pine, spruce and larch respectively. The rest of the sections are made of pine, treated with different wood preservations. The aim of this study is to find the most appropriate wood material for a specific construction, in this case a noise barrier, regard to durability and decomposition, and in the extension to find the most ecological and economic wood material. By comparing different wood species and preservations of wood regard to durability of outdoor exposed wood gives an indication of the most appropriate wood material to be chosen for this type of construction. The untreated spruce, pine and larch boards in contact with ground is in a bad condition, an assessed service life of about 5-15 years according to the results in this study, while the untreated wood above ground is hardly affected at all by biological attacks. No degradation is detected on the different preserved pine sections. More data is needed to assess the residual service life of the wood preserved sections.
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| 2. |
- Bellander, Rickard
(författare)
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Testing large samples of PCM in water calorimeter and PCM used in room applications by night-air cooling
- 2005
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The latent-heat-storage capacity in Phase-Change Materials can be used for storing or releasing energy within a small temperature interval. Upon the phase transition taking place in a narrow temperature span, the material takes up or releases more energy compared to sensible heat storage. For an ideal phase-change material, the transition temperature is a single value, but for the most common phase-change materials on the market, used in building applications, the transition temperature is distributed within a temperature range of several degrees. Integration of phase-change materials in building applications can be effected in several ways, for example by impregnating phase-change materials into porous building materials like concrete, wallboards, bricks or complements of the building structure. Integrating storages filled with phase-change materials makes other implementations, for instance accumulating tanks or envelopes as presented in this thesis, in an air heat exchanger. An appropriate phasetransition temperature of the supposed application is critical to the functionality of the material. For example, in cooling applications, the transition temperature of the material should be a few degrees lower than the requested comfort temperature in the building, and the opposite for heating applications. In order to assess the thermal properties and the durability of the material, a watercalorimetric equipment was developed and employed in an accelerated testing programme. The heat capacity of the material and in particular possible change in the heat capacity over time, after thermal cycling of the material, were measured. In the thermal cycling of the material from solid to liquid phase, the temperature rise and required energy supply were recorded. The testing programme was undertaken according to control procedures and documents. In order to be able to utilize the heat-storage capacity in the best way, it is necessary to gain knowledge about thermal properties of the material, especially the long-term behaviour of the material and the deterioration rates of the thermal properties. A semi-full-scale air heat exchanger based on phase-change material was developed and tested under real temperature conditions during the summer of 2004. The test results were used to compare and verify computer simulations made on a similar plant. The air heat exchanger utilises the ambient diurnal temperature swing to charge and discharge the phasechange material. The material tested in the calorimeter and in the air heat exchanger has an estimated phase-change temperature of about 24 °C.
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| 3. |
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| 4. |
- Hallberg, Daniel, et al.
(författare)
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Beständighet hos trä – utvärdering av långtidsförsök med bullerplank av trä
- 2004
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Rapport (populärvet., debatt m.m.)abstract
- Rapporten redovisar resultatet av en långtidsstudie rörande biologisk nedbrytning av ett bullerplank, uppfört 1996, längs Arlandabanan, snabbtågsförbindelsen mellan Stockholms C och Arlanda flygplats. Bullerplanket är till största del byggt av lärkträ men ett antal testsektioner är uppbyggda av andra träslag och behandlade med olika impregneringsmedel. Resultatet från projektet visar att endast de plankor som är i direktkontakt med marken har angripits av röta. De oimpregnerade sektionerna uppvisar högre grad av rötangrepp än de impregnerade furusektionerna. Någon skillnad mellan obehandlad furu och lärk med avseende på rötangrepp har inte gått att finna. En slutsats som kan dras med utgångspunkt från studiens resultat är att impregnerat virke är mycket mer beständigt än obehandlat virke med avseende på rötangrepp. Beständigheten mot biologiska angrepp kommer inte enbart att vara den kritiska faktorn för det studerade bullerplanket. En kombination av de vibrationer och skakningar som uppstår vid förbipasserande tåg kommer att leda till mekanisk nedbrytning av planket. Effekten av den mekaniska nedbrytningen har dock inte undersökts. Även de estetiska faktorerna bör beaktas såsom klotter och klottersanering och hur en eventuell klottersanering kommer att påverka trävirket. För att i framtiden följa nedbrytningen av bullerplanket bör en eventuell uppföljning av projektet göras om 5-10 år. Resultatet kan ses som ett bidrag till framtida forskning inom beständighetsområdet och livslängdbestämning av behandlat och obehandlat trä. Förhoppningen är att resultatet även skall ge en fingervisning om bästa val av material och konstruktionsutformning, för såväl privatpersoner som för projektörer och andra aktörer i byggsektorn.
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| 5. |
- Hed, Göran, et al.
(författare)
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Mathematical modelling of PCM air heat exchanger
- 2006
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Ingår i: Energy and Buildings. - : Elsevier BV. - 0378-7788 .- 1872-6178. ; 38:2, s. 82-89
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Tidskriftsartikel (refereegranskat)abstract
- In order to cool a room with a cold night air phase change material, PCM, is stored in an air heat exchanger. During night the PCM crystallises, energy is released. During daytime air is circulated in the unit, energy is absorbed and the indoor air is cooled. The characteristic of PCM is that there is an increase of the specific heat over a limited temperature span. This is the principle that is used in the design of the PCM air heat exchanger unit. The action of a PCM storage unit will act differently depending of the thermal properties of the material. In an ideal material the phase transition occurs at a given temperature. On the market, compounds containing PCM are available which, in order to create a suitable melting temperature, are mixtures of different products. In these materials, the transition from liquid to solid takes place over a temperature span, i.e. the specific heat varies with the temperature. This can be represented by a c(p)(T) curve, specific heat as a function of the temperature. In this paper, the development of a mathematical model of the PCM air heat exchanger is presented. Considerations are taken to different shapes of the cp(T) curve. The mathematical model is verified with measurement on a prototype heat exchanger. The development of the equipment is part of the CRAFT project Changeable Thermal Inertia Dry Enclosures (C-TIDE) the possibility of use of phase change materials integrated into a building is explored.
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| 6. |
- Hed, Göran, et al.
(författare)
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Service life testing of PCM based components in buildings
- 2005
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Ingår i: 10DBMC International Conference of Building Materials and Components. ; , s. 253-260
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In the CRAFT project C-TIDE (Changeable Thermal Inertia Dry Enclosures) the possibility of changing the thermal inertia of lightweight buildings with PCM, Phase Change Material, is explored. The project is performed in collaboration with Italian and Swedish partners representing both the industry and research. Lightweight buildings represent a well-established technology in Sweden. In Italy this technology is entering the market. A problem is the overheating of the building during the hot season, especially in warm climate but also in Nordic climate during summer. This project deals mainly with this problem. A crucial issue of the use of these materials is the performance over time data of the phase change material that are used in the building. An extensive program is set up to perform long time testing of the thermal properties of the materials that were used in the project. The long time testing programme of the materials was established to correspond with the governing procedure set up by ISO 15686-2 "Buildings and consructed assets– Service life planning – Part 2: Service life prediction procedures". This paper describes the framework of the testing procedure, the set-up of the testing equipment and preliminary results of the tests.
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