| 1. |
- Gustafsson, Stig-Inge, et al.
(författare)
-
ON YELLOW DISCOLORATIONS WHEN DRYING OAK, QUERCUS ROBUR
- 2008
-
Ingår i: DREWNO-WOOD. - Poznan, Poland : Instytut Technologii Drewna. - 1644-3985. ; 51:179, s. 29-44
-
Tidskriftsartikel (refereegranskat)abstract
- Growing trees many times contain more water than wood. When wood is to be utilized in the form of furniture it must therefore be dried in a kiln-dryer. In such a dryer the climate is very humid and warm which is ideal for many microorganisms such as bacteria and fungi. During their metabolism they change the chemical environment which sometimes lead to undisireable effects such as discolorations. In this paper we have examined specimen from oak, Quercus robur, collected from some parquet floor factories in Sweden. During drying some of these wood battens were affected with yellow streaks and spots which made the wood impossible to use for flooring. By examining small samples of the battens in light, as well as in scanning electron microscopes, we found that fungi grew inside the wooden tissue. By cultivation on agar plates we found several species where one has been identified as Penicillium roqueforti and another one as Paecilomyces variotii. We have also found that these fungi are extremely sensitive to high pH-values, so by spraying the wood with solutions of high pH already in the sawmill will probably make this problem much smaller.
|
|
| 2. |
- Alanne, K., et al.
(författare)
-
Multi-criteria evaluation of residential energy supply systems
- 2007
-
Ingår i: Energy and Buildings. - : Elsevier BV. - 0378-7788 .- 1872-6178. ; 39:12, s. 1218-1226
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, we consider the selection of a residential energy supply system as a multi-criteria decision-making problem, which involves both financial and environmental issues. Specifically, we compare micro-CHP (micro-cogeneration) heating with traditional heating systems through an evaluation that accounts for: (i) the decision-makers' subjective preferences, (ii) uncertainties in the performance of micro-CHP heating systems (which are partly caused by the lack of long-term operational experiences) and (iii) the context-dependency of life-cycle costs and environmental burdens of heating systems. Motivated by these considerations, we employ the PAIRS multi-criteria decision-making methodology that captures incomplete information by way of interval-valued parameters and provides support for sensitivity analyses, too. Our comparative analysis of alternative heating systems suggests that micro-CHP is a reasonable alternative to traditional systems, particularly from the environmental point of view. © 2007 Elsevier B.V. All rights reserved.
|
|
| 3. |
|
|
| 4. |
- Gebremedhin, Alemayehu, 1962-, et al.
(författare)
-
Energisystemanalys Solna
- 2004
-
Rapport (övrigt vetenskapligt/konstnärligt)
|
|
| 5. |
- Gustafsson, Stig-Inge
(författare)
-
Are Earth Tube Heat Exchangers of Interest when Heating Buildings?
- 1993
-
Ingår i: International Journal of Energy Research. - : Hindawi Limited. - 0363-907X .- 1099-114X. ; 17:7, s. 597-604
-
Tidskriftsartikel (refereegranskat)abstract
- It is a well-known fact that the temperature of the soil, some metres below the surface, is relatively stable. If this heat could be utilized by use of an earth tube heat exchanger, significant benefits could occur when space heating for buildings is considered. The inlet ventilation air is then led through a long earth tube in which it will, depending on their relative temperatures, take up heat from, or leave heat to, the surrounding soil. In this paper two case studies are presented. The buildings of concern are sited in the vicinity of Linköping, about 200 km south of Stockholm, Sweden. One of the cases utilizes heat from the earth tube in an air-to-water heat pump, while the other uses an air-to-air heat exchanger. The studies show that the earth tubes only to a very low degree contribute to the need of added heat in order to achieve a desirable indoor climate. Hence, the extra cost for the tube will not be balanced by the decreased cost for space heating. This discouraging result may have depended on heat pipes that were too short or the fact that the difference in temperature between the passing air stream and the surrounding soil was too small.
|
|
| 6. |
- Gustafsson, Stig-Inge
(författare)
-
Carpentry factory and municipal electricity loads
- 1998
-
Ingår i: Energy Conversion and Management. - : Elsevier. - 0196-8904 .- 1879-2227. ; 39:3-4, s. 343-347
-
Tidskriftsartikel (refereegranskat)abstract
- Load management of electricity loads has received more interest in recent years. At least in Sweden, this is natural because of a rather cheap energy price, while at the same time, the demand charge is high. If a company could save the precise kWh that build the peak demand, then these would have a value of more than 200 times the off-peak kWh. This paper deals with monitored electricity data for two carpentry industries and one municipality, both situated in the south of Sweden. The ideal ! situation would be if the industry could reduce their peak demand and, at the same time, reduce the peak for the utility. Both participants would, in that case, save money, and the payback time for load management equipment would decrease substantially. If, however, a load management system at the carpentry transfers kWh to peak hours for the utility, the industry will save money, while the utility gets higher costs. The result of the study is that the Swedish electricity rates in use today are a very poor means of encouraging worthwhile load management, and often, they even aggravate the situation.
|
|
| 7. |
- Gustafsson, Stig-Inge
(författare)
-
Climate Influence on District Heat and Electricity Demands
- 1992
-
Ingår i: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 42:4, s. 313-320
-
Tidskriftsartikel (refereegranskat)abstract
- This paper describes the district heating and electricity load of Kalmar, Sweden. Unfortunately, it has not been possible to examine one full year because the monitoring of the energy use for district heating and electricity, and the outdoor temperature, did not exactly overlap. However, more than 7200 h, of the 8760 in a full year, have been examined. It is shown that the district heat load has a far higher correlation with the outdoor temperature (a coefficient of 0·89), than has the electricity load (0·33). Thus, it is much easier to predict the influence of, e.g. an insulation retrofit for the building stock where district heating is used compared with electricity space heating. It is also shown how an estimate can be made of the thermal transmission factor for the total building stock.
|
|
| 8. |
- Gustafsson, Stig-Inge, et al.
(författare)
-
Differential Rates for District Heating and the Influence on the Optimal Retrofit Strategy for Multi-Family Buildings
- 1987
-
Ingår i: Applied Thermal Engineering. - : Elsevier BV. - 1359-4311 .- 1873-5606. ; 7:4, s. 337-341
-
Tidskriftsartikel (refereegranskat)abstract
- When renovating existing multi-family buildings it is very important to implement the best retrofit strategy possible in order to minimize the remaining life-cycle cost for the building. If the building is heated with district heating this strategy of course changes due to the energy rate used by the utility. It is also very important for the utility that the consumer is encouraged to save energy when there is a need for it, i.e. during peak load conditions. Our paper shows that an accurate cost differential rate provides all these facilities.
|
|
| 9. |
- Gustafsson, Stig-Inge
(författare)
-
Does postponed retrofitting save money?
- 1995
-
Ingår i: Heat Recovery Systems and CHP. - : Elsevier. - 0890-4332. ; 15:5, s. 469-472
-
Tidskriftsartikel (refereegranskat)abstract
- When a building is to be retrofitted, or refurbished, it is always of importance to study the building as a complete energy system. At least in Sweden, the building process is divided between different professional categories, such as HVAC and ordinary building contractors. It is therefore not surprising that the HVAC contractor wants to maximise his profit by installing large and sophisticated equipment at the same time as the builder or architect wants to design a house with very thick walls and high performing windows. These competing interests will often result in a building where the heating system is not adjusted to the rest of the house, but is instead far too powerful. The recommendation from life-cycle cost analyses has therefore always been to study the building as a whole system and to apply an optimal solution at one specific base year; this is probably always the best solution in order to minimise the life cycle cost, but experience shows that the proprietor of the building often hesitates in doing so. The reason for this is his lack of money. Changing the building into an optimal energy system frequently requires a heavy investment in any one specific year, albeit the best solution in the long run. This paper will discuss what happens to the life-cycle cost when retrofits are postponed so as to fit into the proprietor's “10 yr budget”.
|
|
| 10. |
|
|
