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Energy Efficient Window Systems. Effects on Energy Use and Daylight in Buildings.

Bülow-Hübe, Helena LU (2001) In Rapport TABK
Abstract (Swedish)
Popular Abstract in Swedish

Denna avhandling handlar om energieffektiva fönstersystem i svenska byggnader. Simuleringar av energianvändningen har gjorts för både småhus och kontor för att bedöma effekterna av olika fönsterval på energibehov och inneklimat. Två års mätningar av energianvändning och innetemperaturer för ett energisnålt radhus har utvärderats. Två beteendestudier har även genomförts för att studera 1) effekterna på utsikt och rumsupplevelse av reducerad dagsljustransmission i samband med superisolerade fönster samt 2) användningen av utvändiga solskydd och tillfredsställelsen med den resulterande dagsljusmiljön i kontor.



Resultaten visar att när energieffektiviteten för byggnaden ökar måste... (More)
Popular Abstract in Swedish

Denna avhandling handlar om energieffektiva fönstersystem i svenska byggnader. Simuleringar av energianvändningen har gjorts för både småhus och kontor för att bedöma effekterna av olika fönsterval på energibehov och inneklimat. Två års mätningar av energianvändning och innetemperaturer för ett energisnålt radhus har utvärderats. Två beteendestudier har även genomförts för att studera 1) effekterna på utsikt och rumsupplevelse av reducerad dagsljustransmission i samband med superisolerade fönster samt 2) användningen av utvändiga solskydd och tillfredsställelsen med den resulterande dagsljusmiljön i kontor.



Resultaten visar att när energieffektiviteten för byggnaden ökar måste U-värdet för fönstren minska om det årliga energibehovet inte skall öka eftersom uppvärmningssäsongen blir kortare och det nyttiga soltillskottet minskar. För enfamiljshus med en fönsterarea på 15 % av golvarean och isolerade enligt dagens byggnorm bör U-värdena för fönster därmed vara lägre än 1.0 W/m²K. För hus isolerade enligt 1960 års standard bör U-värdena vara lägre än 1.6 W/²K. I kallare klimat (norra Sverige) bör U-värdena vara något lägre, medan något högre U-värden kan tolereras i mildare klimat (södra Sverige). Den termiska komforten om vintern förbättras alltid med energieffektiva fönster. Problem med övertemperaturer under sommartid kan dock förekomma både i superisolerade småhus och i kontor, vilket indikerar ett behov av låga U-värden i kombination med låg solenergitransmission. Dagsljusstudier indikerar att användningen av två lågemissionsskikt färgar ljuset tillräckligt mycket för att märkas, och färgerna i rummet kan upplevas som mer dämpade och rummet som mer slutet. En kompromiss mellan energieffektivitet och dagsljustransmission kan därför vara nödvändig, och det föreslås att endast ett lågemissionsskikt används utom i situationer då extremt låg energianvändning önskas. (Less)
Abstract
This thesis deals with energy-efficient windows in Swedish buildings. Parametric studies were performed in the dynamic energy simulation tool Derob-LTH in order to study the effects of window choices on energy use and indoor climate for both residential and office buildings. A steady-state program was used to evaluate two years of measurements of energy use and indoor temperatures of an energy-efficient row-house. Two behavioural studies regarding (1) daylight transmittance, view and room perception using super-insulated windows and (2) the satisfaction with the daylight environment and the use of shading devices in response to daylight/sunlight were conducted in full-scale laboratory environments exposed to the natural climate.

... (More)
This thesis deals with energy-efficient windows in Swedish buildings. Parametric studies were performed in the dynamic energy simulation tool Derob-LTH in order to study the effects of window choices on energy use and indoor climate for both residential and office buildings. A steady-state program was used to evaluate two years of measurements of energy use and indoor temperatures of an energy-efficient row-house. Two behavioural studies regarding (1) daylight transmittance, view and room perception using super-insulated windows and (2) the satisfaction with the daylight environment and the use of shading devices in response to daylight/sunlight were conducted in full-scale laboratory environments exposed to the natural climate.



Results show that as the energy-efficiency of buildings increase, window U-values must decrease in order not to increase the annual heating demand, since the heating season is shortened, and useful solar gains become smaller. For single-family houses with a window-to-floor area ratio of 15 % and insulated according the current Swedish building code, the U-values should thus on average be lower than 1.0 W/m²K. For houses insulated according to 1960s standard, the U-value may on average be 1.6 W/m²K. For colder climates (northern Sweden), the U-values should be somewhat lower, while slightly higher U-values can be tolerated in milder climates of south Sweden. Thermal comfort during winter is improved for energy-efficient windows. However, overheating problems exist for both super-insulated houses and highly glazed office buildings showing a need for very low U-values in combination with low g-values. Daylight experiments indicate that the use of two low-emittance coatings tints the transmitted daylight enough to be appreciated, and colours may be perceived as more drab and rooms more enclosed. A compromise between energy-efficiency and daylighting may be needed, and it is suggested that only one coating be used except when very high energy-efficiency is required. (Less)
Please use this url to cite or link to this publication:
author
opponent
  • Professor Hastings, S Robert, Architecture, Energy & Environment GmbH, Switzerland
organization
publishing date
type
Thesis
publication status
published
subject
keywords
simulation, thermal transmittance, solar energy transmittance, shading device, solar protection, cooling, heating, energy demand, building, low-emittance coating, window, glazing, comfort, user aspects, operative temperature, Architecture, Building construction, Byggnadsteknik, daylight, perception, interior design, Arkitektur, inredningsarkitektur, Energy research, Energiforskning
in
Rapport TABK
pages
248 pages
publisher
Lund University, Lund Institute of Technology, Division of Energy and Building Design, P.O. Box 118, SE-221 00 LUND, Sweden,
defense location
Carolinasalen, Kungshuset, Lundagård
defense date
2001-12-10 09:15
external identifiers
  • other:ISRN: LUTADL/TABK--1022-SE
ISSN
1103-4467
language
English
LU publication?
yes
id
40898eab-5ebd-4e74-9358-db831c5a06aa (old id 42204)
date added to LUP
2007-06-21 09:38:10
date last changed
2016-09-19 08:44:55
@phdthesis{40898eab-5ebd-4e74-9358-db831c5a06aa,
  abstract     = {This thesis deals with energy-efficient windows in Swedish buildings. Parametric studies were performed in the dynamic energy simulation tool Derob-LTH in order to study the effects of window choices on energy use and indoor climate for both residential and office buildings. A steady-state program was used to evaluate two years of measurements of energy use and indoor temperatures of an energy-efficient row-house. Two behavioural studies regarding (1) daylight transmittance, view and room perception using super-insulated windows and (2) the satisfaction with the daylight environment and the use of shading devices in response to daylight/sunlight were conducted in full-scale laboratory environments exposed to the natural climate.<br/><br>
<br/><br>
Results show that as the energy-efficiency of buildings increase, window U-values must decrease in order not to increase the annual heating demand, since the heating season is shortened, and useful solar gains become smaller. For single-family houses with a window-to-floor area ratio of 15 % and insulated according the current Swedish building code, the U-values should thus on average be lower than 1.0 W/m²K. For houses insulated according to 1960s standard, the U-value may on average be 1.6 W/m²K. For colder climates (northern Sweden), the U-values should be somewhat lower, while slightly higher U-values can be tolerated in milder climates of south Sweden. Thermal comfort during winter is improved for energy-efficient windows. However, overheating problems exist for both super-insulated houses and highly glazed office buildings showing a need for very low U-values in combination with low g-values. Daylight experiments indicate that the use of two low-emittance coatings tints the transmitted daylight enough to be appreciated, and colours may be perceived as more drab and rooms more enclosed. A compromise between energy-efficiency and daylighting may be needed, and it is suggested that only one coating be used except when very high energy-efficiency is required.},
  author       = {Bülow-Hübe, Helena},
  issn         = {1103-4467},
  keyword      = {simulation,thermal transmittance,solar energy transmittance,shading device,solar protection,cooling,heating,energy demand,building,low-emittance coating,window,glazing,comfort,user aspects,operative temperature,Architecture,Building construction,Byggnadsteknik,daylight,perception,interior design,Arkitektur,inredningsarkitektur,Energy research,Energiforskning},
  language     = {eng},
  pages        = {248},
  publisher    = {Lund University, Lund Institute of Technology, Division of Energy and Building Design, P.O. Box 118, SE-221 00 LUND, Sweden,},
  school       = {Lund University},
  series       = {Rapport TABK},
  title        = {Energy Efficient Window Systems. Effects on Energy Use and Daylight in Buildings.},
  year         = {2001},
}