Daylight usage in buildings improves visual comfort and lowers the final energy demand for artificial lighting. The question that always occurs is how much conservation can be achieved? New or rare materials and constructions have a lack of information about their application. Therefore, the current investigation quantifies the daylight and energy performance of a rare multi-layer textile membrane roof. A translucent, thermal insulation with a glass fibre fleece between the two roof membranes combines daylight usage and heating demand reduction. A sports hall built in 2017 is used as a case study building with 2300 m 2 membrane roof surface. The optical properties of the roof construction were measured with a total visual light transmittance τ v of 0.72% for a clean surface. A climate-based annual daylight modelling delivers daylight indicators for different construction scenarios. The results show that, in comparison to only one glass façade, the additional translucent and thermally insulated membrane roof construction increases the annual daylight autonomy (DA 700 ) from 0% to 1.5% and the continuous DA 700 from 15% to 38%. In the roof-covered areas of the sport field, this results in a 30% reduction of the electricity demand for artificial lighting from 19.7 kWh el /m 2 /a to 13.8 kWh el /m 2 /a, when a dimming control is used. The study also found that the influence of the soiling of one layer decreases its light transmittance by a factor 0.81. Two soiled layers lower τ v by a factor of 0.66 to 0.47%. This increases the electricity demand for lighting by only 12%. The results should be very valuable as a comparison and benchmark for planners and future buildings of a similar type.

No abstract

Daylight usage in buildings improves visual comfort and lowers the final energy demand for artificial lighting. The question that always occurs is how much conservation can be achieved? New or rare materials and constructions have a lack of information about their application. Therefore, the current investigation quantifies the daylight and energy performance of a rare multilayer textile membrane roof. A translucent, thermal insulation with a glass fibre fleece between the two roof membranes combines daylight usage and heating demand reduction. A sports hall built in 2017 is used as a case study building with 2300 m 2 membrane roof surface. The optical properties of the roof construction are measured with a total visual light transmittance τv of 0.72 % for a clean surface. A climate-based annual daylight modelling delivers daylight indicators for different construction scenarios. The results show that in comparison to only one glass facade, the additional translucent and thermally insulated membrane roof construction increases the annual daylight autonomy (DA700) from 0 % to 1.5 % and the continuous DA700 from 15% to 38 %. In the roof-covered areas of the sport field, this results in a 30 % reduction of the electricity demand for artificial lighting from 19.7 to 13.8 kWhel/m²/a, when a dimming control is used. The study also found out, that the influence of the soiling of one layer decreases its light transmittance by a factor 0.81. Two soiled layers lower τv by a factor 0.66 to 0.47 %. This increases the electricity demand for lighting by only 12 %. The results should be very valuable as a comparison and benchmark for planners and future buildings of a similar type.

Der folgende Beitrag befasst sich mit der Tageslichtwirkung eines transluzenten, thermisch gedämmten Membrandaches über einer Sporthalle aus energetischer Sicht. Anhand von Messungen der optischen Eigenschaften der ausgeführten Dachkonstruktion wird eine dynamische Tageslichtsimulation der realisierten Situation über ein Jahr durchgeführt. Weitere Szenarien mit veränderten Materialeigenschaften und Konstruktionen liefern Vergleichswerte zur Quantifizierung der durch das Membrandach erreichten Reduktion des Kunstlichtbedarfs. Auf den Aspekt der Verschmutzung der Oberflächen und damit einhergehende Reduktion des Lichttransmissionsgrads wird explizit eingegangen. Bei einem Transmissionsgrad von 0,72 % wird im Vergleich zu einer alleinigen Glasfassade der Kunstlichtbedarf um 30 % von 19,7 kWhel/m2/a auf 13,8 kWh el/m2/a gesenkt. Die Seltenheit der Membranbauten verursacht eine Spärlichkeit an Betriebserfahrung und Informationen zu Kennwerten. Die Ergebnisse der vorliegenden Arbeit stellen daher als Vergleichs‐ und Kennwerte wertvolle, neue Erkenntnisse für viele Architekten, Planer und Bauherren dar.

Energy-efficient heating and cooling systems as well as intelligent systems for energy distribution are urgently required in order to be able to meet the ambitious goals of the European Union to reduce greenhouse gas emissions. The present article is intended to show that intelligent system extensions for the area of heating, cooling and electricity production for the industrial sector can lead to significant increase in efficiency. For this purpose, a simulation study for the expansion of a combined heat and power (CHP) plant with 2 MW thermal output using a 1.4 MW absorption chiller has been carried out. This shows that a heat-controlled CHP unit can significantly increase its running time. A system model was created for the initial situation and validated with existing measurement data. In the second step, this model was expanded to include the ACM module. The simulation was able to prove that in the event of a system expansion, the run time of the CHP unit can be increased by 35%. In addition to then increase of energy efficiency in the supply system, the analysis also focuses on the efficiency of the energy distribution via thermal networks in an industrial environment. The presented paper therefore also highlights the optimization potentials in the operation of thermal supply networks for industrial applications. For this purpose, a mathematical model has been developed which in addition to the components of the thermal network itself also comprises the producers and consumers. The specific construction of thermal networks for the supply of industrial properties requires adapted solutions for the simulation of such systems. Therefore, amongst other things, in the paper, solutions are shown for the modelling of direct flow local heating networks as well as for the operation of a cascade-controlled pump group.