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| 2. |
- Ossman, Lisa, et al.
(författare)
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Nulägesanalys för satsning på NNE byggnader : slutrapport etapp 1
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Det övergripande syftet med uppdraget är att få en detaljerad bild över byggnaders energiprestanda i Sverige. Den första etappen, förstudien, går ut på att beskriva metoden för hur denna analys ska göras. Som etapp 2 genomförs själva nulägesanalysen och slut¬ligen i etapp 3 analyseras resultat och slutsatser presenteras. I denna rapport redogörs för etapp 1, dvs metodbeskrivningen för nulägesanalysen. Nulägesanalysen ska senare kunna användas för att följa upp hur satsningar på Näranoll¬energibyggnader (NNE) påverkar energianvändningen i hela byggnadsbeståndet, inte bara i de faktiska demonstrationsprojekt som beviljas stöd och där uppföljning är betydligt enklare. Resultatet av nulägesanalysen, och den uppföljande analysen (planerad till 2015), ska i förlängningen kunna vara ett stöd när de nationella målnivåerna för näranollenergi-byggnader bestäms. I denna rapport redogörs för etapp 1, dvs metodbeskrivningen för nulägesanalysen. Rapporten beskriver vilka statistikkällor som finns idag samt en metod för hur dessa kan bidra till en mer detaljerad bild av byggnaders energiprestanda under ett valt referensår.
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| 3. |
- Boss, Annika, et al.
(författare)
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Uppvärmning och kylning av lokaler ur energi- och miljömässigt samt ekonomiskt perspektiv
- 2009
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Rapport (refereegranskat)abstract
- Demand for cooling of commercial buildings is increasing and there is a potential for expanding district cooling systems, especially in district heating areas. Using district heating and district cooling has been compared to heat pump techniques. Primary energy, environmental influence and economy have been evaluated. Four buildings in Gothenburg have been included in the study and certain differences have been found depending on demands of heating and cooling, which vary according to design and activity. The results are specific for Gothenburg due to the combination of production methods for district heating and cooling and the pricing, which differ compared to other places. Different perspectives on production of electricity, district heating and district cooling, e.g. average or marginal production, is of vital importance when comparing environmental influence. In most of the case studies the demand of primary energy is lower for district heating and cooling compared to heat pump systems. With a marginal perspective district heating and cooling will lead to lower emissions of greenhouse gases. Using the perspective of average production will on the other hand rate heat pump systems to have a lower influence on the greenhouse effect in most of the cases. Which technique is the most cost efficient depends mainly upon relation of heating and cooling demands. Where there is a greater demand for cooling than for heating, district heating and cooling is more advantageous. It is a need for improved data in commercial buildings from reliable field measurements. The quality of the evaluation is very much dependent on reliable measured data from real installations.
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| 4. |
- Gustafsson, Ola, et al.
(författare)
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Flat tube heat exchangers - Direct and indirect noise levels in heat pump applications
- 2014
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Ingår i: Applied Thermal Engineering. - : Elsevier BV. - 1359-4311. ; 66:1-2, s. 104-112
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Tidskriftsartikel (refereegranskat)abstract
- In the outdoor unit of an air-source heat pump the fan is a major noise source. The noise level from the fan is dependent on its state of operation: high air-flow and high pressure drop often result in higher noise levels. In addition, an evaporator that obstructs an air flow is a noise source in itself, something that may contribute to the total noise level. To be able to reduce the noise level, heat exchanger designs other than the common finned round tubes were investigated in this study. Three types of heat exchanger were evaluated to detect differences in noise level and air-side heat transfer performance at varying air flow. The measured sound power level from all the heat exchangers was low in comparison to the fan sound power level (direct effect). However, the heat exchanger design was shown to have an important influence on the sound power level from the fan (indirect effect). One of the heat exchangers with flat tubes was found to have the lowest sound power level, both direct and indirect, and also the highest heat transfer rate. This type of flat tube heat exchanger has the potential to reduce the overall noise level of a heat pump while maintaining heat transfer efficiency.
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| 5. |
- Gustafsson, Ola, et al.
(författare)
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Heat exchanger design aspects related to noise in heat pump applications
- 2016
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Ingår i: Applied Thermal Engineering. - : Elsevier. - 1359-4311 .- 1873-5606. ; 93, s. 742-749
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Tidskriftsartikel (refereegranskat)abstract
- An increased use of heat pumps is one of the measures that can be taken to reduce energy consumption on a large scale. For a wider acceptance, and major heat pump market expansion, it is crucial to develop heat pumps that cause minimal disturbance. Results from field measurements made by SP Technical Research Institute of Sweden indicate that the use of indirect heat pumps has potential to significantly reduce the outdoor noise level of ambient air heat pumps. The noise level caused by such heat pumps has been shown to be highly influenced by the design of the air-to-fluid heat exchanger. The overall purpose of this study is to propose a design of an air-to-fluid heat exchanger that allows for a well performing system as well as a low level of noise and cost. Two different types of heat exchangers, with flat tubes and round tubes, are compared theoretically. According to the modelling results, a heat exchanger with flat tubes and plain fins is the most suitable out of the studied designs due to its low heat transfer resistance on the tube side. The round tube heat exchangers showed to be significantly less suitable, displacing more than twice the volume.
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| 6. |
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| 7. |
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| 8. |
- Haglund Stignor, Caroline
(författare)
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Comparison of energy use and cost in different indirect cooling systems
- 2007
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Rapport (refereegranskat)abstract
- A case study has been performed comparing 11 different cases of indirect cooling systems in supermarkets. The influence of the selection of cooling-coil / heat exchanger design, display cabinets, type of secondary refrigerant, types of valves, types of pumps and type of system design has been investigated. The cases have been selected to be representative for a large number of supermarkets in Sweden. However, some of the cases are only hypothetical and do no not exist in reality so far. The results show that savings of both energy and money can be significant, by the selection of efficient components and system design. An iterative procedure, for finding the optimal operating point (liquid inlet temperature and liquid flow rate) is suggested. This procedure has been evaluated with good results.
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| 9. |
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| 10. |
- Haglund-Stignor, Caroline, et al.
(författare)
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Det energieffektiva kylbatteriet
- 2004
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Ingår i: 3:a eff-Sys-dagen. ; 1
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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