| 1. |
- Dalenbäck, Jan-Olof, 1954, et al.
(author)
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Ställ tekniska egenskapskrav och använd deklarationerna
- 2014
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In: Energi & Miljö. - 1101-0568. ; 2014:4, s. 40-41
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Journal article (other academic/artistic)abstract
- Ta bort energikraven i BBR och ersätt dem med ändamålsenliga egenskaps¬krav. Gör sedan energideklarationerna värda namnet genom att inkludera hushålls- och verk¬sam¬hets¬el så att de kan användas för att följa upp energi¬användningen. I anslutning till Boverkets regeringsuppdrag (N2014/75/E) att definiera nya energihus¬håll¬ningskrav, finns det all anledning att diskutera om vi är på rätt väg med de krav på bygg¬naders energi¬prestanda som ställs i Boverkets Byggregler (BBR). Speciellt om dess uppfyllelse ska vara juridiskt bindande.
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| 2. |
- Filipsson, Peter J, 1985, et al.
(author)
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A thermal model of an active chilled beam
- 2017
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In: Energy and Buildings. - : Elsevier BV. - 0378-7788. ; 149, s. 83-90
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Journal article (peer-reviewed)abstract
- Active chilled beams (ACBs) have gained increased recognition as a feasible technology for comfort cooling during the last decades. One of the advantages with such systems is utilization of high temperature cooling. This provides exergetic benefits and also reduces the need for individual room control. However, individual room control normally serves as compensation for the safety margin applied when dimensioning the cooling systems. Therefore, the absence of individual room controls calls for accurate dimensioning tools. This paper presents a model to be used to calculate cooling capacities of ACBs. The model is based on NTU analysis and is a hybrid of first principles and empirical data in order to ensure high accuracy without requiring extensive measurements for model calibration. The model explicitly captures the influence of buoyant forces acting on the air passing the chilled coil in the beam. Output from the model also includes temperature and flow of supply air. The model shows good compliance with measured data in a wide range of operating conditions (average error of 1.7% if six cases is used for model calibration). The model can be appropriately implemented in building performance simulation tools, thus improving the design of ACB systems.
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| 3. |
- Filipsson, Peter J, 1985, et al.
(author)
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Chilled water temperature control of self-regulating active chilled beams
- 2020
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In: SINTEF Proceedings. - 2387-4295. - 9788253616797 ; 5, s. 230-237
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Conference paper (peer-reviewed)abstract
- The flow rate of chilled water in a self-regulating active chilled beam is constant without respect to the actual cooling load. The cooling capacity is instead determined by the room temperature, which gives rise to the self-regulating effect, and also by the centrally controlled chilled water temperature, which is the focus of this paper . Previous studies have emphasized the benefit of avoiding room-level control equipment, but also highlighted the risk of overcooling with detrimental effects on thermal climate and energy demand. Overcooling may be avoided by supply temperature control, but strategies have not yet been studied in systems operating in cooling mode only. Simulations are carried out with IDA ICE. The results show that overcooling is effectively avoided by proper control of the chilled water temperature. Desired thermal climate is achieved and the energy demand is in the same order of magnitude as in a system with individually and ideally PI-controlled active chilled beams.
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| 4. |
- Filipsson, Peter J, 1985, et al.
(author)
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Induction ratio of active chilled beams - Measurement methods and influencing parameters
- 2016
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In: Energy and Buildings. - : Elsevier BV. - 0378-7788. ; 129, s. 445-451
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Journal article (peer-reviewed)abstract
- In active chilled beams, primary air from the air handling unit induces room air which passes a cooling coil before it mixes with the primary air and discharges into the room. The ratio of induced room air flow to the primary air flow is the induction ratio (IR). Knowledge about the IR is important when modelling cooling capacity as well as temperature and velocity of the air discharged from the beam. Most previous studies of the behavior of IR are focusing on the influence of primary air flow. The purpose of the work presented in this paper is to investigate whether other operating conditions also influence the IR. Three methods of determining the IR are compared in order to strengthen the conclusions. The results indicate that the IR is influenced by the chilled water temperature due to buoyant forces. Novel methods of determining the IR are presented and it is concluded that current methods may lead to overestimation.
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| 5. |
- Filipsson, Peter J, 1985, et al.
(author)
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Modelling of rooms with active chilled beams
- 2020
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In: Journal of Building Performance Simulation. - : Informa UK Limited. - 1940-1493 .- 1940-1507. ; 13:4, s. 409-418
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Journal article (peer-reviewed)abstract
- Active chilled beams (ACBs) are often modelled as generic cooling devices. Due to induction, the air flow discharged from an ACB is several times higher than supplied from the air handling unit, and due to its design, it affects the temperature of the ceiling to a greater extent than an arbitrary cooling device. This paper investigates the impact of taking these features into account when simulating air and operative temperature in a room equipped with an ACB. The building performance simulation software IDA ICE is used for analysis and the simulations are compared with full-scale experiments. The main findings are that simulations which take into account the features mentioned above correspond more closely with measurements. If designing for a certain operative temperature, this reduces the required design cooling capacity. Although negligible in many applications, the magnitude of this reduction is 9% with high-temperature cooling.
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| 6. |
- Filipsson, Peter J, 1985, et al.
(author)
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Performance evaluation of a direct ground-coupled self-regulating active chilled beam system
- 2020
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In: Energy and Buildings. - : Elsevier BV. - 0378-7788. ; 209
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Journal article (peer-reviewed)abstract
- Active chilled beams support high temperature cooling which enables the opportunities of direct ground-coupling and self-regulation. Direct ground-coupling implies cooling through a ground heat exchanger without use of a chiller and self-regulation refers to the elimination of individual room control systems. This paper presents the operation and indoor air temperatures in such an office building located in Stockholm, Sweden, and the analysis includes the unprecedented hot summer of 2018. The results show that the system is capable of supplying the building with enough cooling to not exceed desired indoor air temperature levels. It is also concluded that the self-regulation kept the indoor air temperature satisfactory uniform. The difference between the highest and lowest temperature is 1.9 K on average and below 2.4 K during 90% of the time. Regarding stability, the least stable temperature recorded has a standard deviation of 0.8 K while the average standard deviation is less than 0.5 K. The indoor air temperature during summer is about 2 K lower than suggested by standards. This calls for conducting a thermal comfort survey and may be remedied by increasing the chilled water temperature. To increase the performance of the system, the ground is cooled during winter by preheating the supply air. During 2018, slightly more cooling was extracted in the summer than recharged during winter.
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| 7. |
- Kellner, Johnny, et al.
(author)
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Inför primärenergifaktorer i byggreglerna
- 2014
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In: VVS Forum. ; :1/2014, s. 80-81
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Journal article (other academic/artistic)abstract
- På kort sikt har vi väldigt stora energiresurser. Energi är dessutom billig i förhållande till annat vilket gör att vi använder mycket mer energi än vad som är hållbart i längden. Dessutom påverkas vår miljö och vårt klimat på ett negativt sätt. Därför är det hög tid att se över vår energianvändning och begränsa densamma, oavsett om den är baserad på traditionella eller förnybara energiresurser, då alla kända energiresurser har sina begränsningar.Eftersom det funnits begränsat intresse och möjligheter bland svenska väljare och politiker att införa begränsningar sedan oljekriserna på 70-talet får vi istället rätta oss efter EU-direktiv. Där finns krav på såväl byggnaders ”energiprestanda”, som energieffektivisering och ökad användning av förnybar energi. I det sammanhanget bör Boverket få i uppdrag att ändra energikraven i byggreglerna (BBR) från ett snävt byggnadsperspektiv till ett mer ändamålsenligt energisystemperspektiv. Ett sätt är att införa primärenergifaktorer (PE-faktorer) som viktar de olika energislagen. Det leder dessutom till en ökad nordisk samordning av byggregler och energikrav, vilket t ex föreslagits av Nordiska minsisterrådet, och därmed bättre förutsättningar för rationellt byggande.
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| 8. |
- Andersen, Martin, 1985-, et al.
(author)
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Economic Analysis of Heat Distribution Concepts for a Small Solar District Heating System
- 2022
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In: Energies. - : MDPI. - 1996-1073. ; 15:13
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Journal article (peer-reviewed)abstract
- One challenge in today’s district heating systems is the relatively high distribution heat loss. Lowering distribution temperatures is one way to reduce operational costs resulting from high heat losses, while changing the distribution system from steel pipes to plastic pipes and changing the heat distribution concept can reduce investment costs. The result is that the overall life cycle cost of the district heating system is reduced, leading to the improved cost competitiveness of district heating versus individual heating options. The main aim of this study was to determine the most cost-efficient distribution system for a theoretical solar district heating system, by comparing the marginal life cycle cost of two different distribution systems. A secondary aim was to determine the influence of the employed pipe type and insulation level on the marginal life cycle cost by comparing detailed economic calculations, including differences in pipe installation costs and construction costs, among others. A small solar-assisted district heating system has been modeled in TRNSYS based on a real system, and this “hybrid” model is used as a basis for a second model where a novel distribution system is employed and the heating network operating temperature is changed. Results indicate that a novel distribution concept with lower network temperatures and central domestic hot water preparation is most efficient both from an energy and cost perspective. The total life cycle costs vary less than 2% for a given distribution concept when using different pipe types and insulation classes, indicating that the investment costs are more significant than operational costs in reducing life cycle costs. The largest difference in life cycle cost is observed by changing the distribution concept, the novel concept having approximately 24% lower marginal life cycle cost than the “hybrid” system. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.
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| 9. |
- Andersen, Martin, 1985, et al.
(author)
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Heat distribution concepts for small solar district heating systems – Techno-economic study for low line heat densities
- 2022
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In: Energy Conversion and Management: X. - : Elsevier BV. - 2590-1745. ; 15
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Journal article (peer-reviewed)abstract
- The high operating temperatures in today's district heating networks combined with the low energy demand of new buildings lead to high relative network heat losses. New networks featuring lower operating temperatures have reduced relative heat losses while enabling an increase in the use of solar heat. The primary aim of this study was to determine if a particular district heating system can be made more effective with respect to heat losses and useful solar energy, by considering different distribution concepts and load densities. A small solar assisted district heating system with a novel hybrid distribution system has been modelled based on a real case study. This model serves as a basis for two other models where the distribution system and heating network operating temperature is changed. A secondary aim of the study was to determine the economic implications of making these changes, by using costs estimates to calculate the contribution of essential system components to total system cost. Results indicate that a novel distribution concept with lower network temperatures and central domestic hot water preparation is most energy efficient in a sparse network with a heat density of 0.2 MWh/m∙a and a performance ratio of 66%, while a conventional district heating system performs worst and has a performance ratio of less than 58% at the same heat density. In an extremely sparse network with heat density of 0.05 MWh/m∙a, the performance ratio is 41% and 30% for these systems, respectively. A simple economic analysis indicates that the novel distribution concept is also best from an economic point of view, reducing the initial investment cost by 1/3 compared to the conventional concept, which is the most costly. However, more detailed calculations are needed to conclude on this.
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| 10. |
- Andersen, Martin, 1985, et al.
(author)
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Techno-economic analysis of solar options for a block-heating system
- 2018
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In: Solar Energy. - 0038-092X.
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Journal article (peer-reviewed)abstract
- An innovative small solar district heating system with one central heating plant and four solar substations has been built in Vallda Heberg, Sweden, to supply a new housing area with passive houses. The target solar fraction was 40% and the total system design, including heat distribution in the buildings, was based on previous experience and aimed to be simple and cost-effective. The main aim of this study was to determine whether the system can be designed in a more effective manner by change of distribution system and load density. TRNSYS models were calibrated against measured data and then used to predict the energy performance. Results indicate that lower distribution heat losses can be obtained by change to a novel distribution concept with lower operating temperatures, while potentially reducing cost. Increases in heat density cause reduced distribution losses and boiler supplied heat demand, with only minor effects on solar system yield.
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