The Velux Building NatVent Presentation of the building Presentation of the building The design issue The design issue The building concept The building concept The winter monitoring The winter monitoring The summer monitoring The summer monitoring Major findings Major findings The VELUX building The VELUX building More information... More information... Back to “Select a building” Back to “Select a building”

NatVent Presentation of the building Presentation of the building The design issue The design issue The building concept The building concept The winter monitoring The winter monitoring The summer monitoring The summer monitoring Major findings Major findings The VELUX building The VELUX building More information... More information... Back to “Select a building” Back to “Select a building” Project presentation (1...) The Velux building is situated in central Switzerland in the tableland. This area is characterised by a moderate and sometimes windy climate. The building was renovated in 1992: the former flat roof was topped by two additional floors with tilted outside walls resulting in the new roof. The building is used as an administration building of a factory for window fittings. The building has many cellular offices, an open plan office and a big show room. The rooms have a lot of internal mass: exposed ceilings and tiled floors (the internal walls and external walls are light-weight constructions).

NatVent Presentation of the building Presentation of the building The design issue The design issue The building concept The building concept The winter monitoring The winter monitoring The summer monitoring The summer monitoring Major findings Major findings The VELUX building The VELUX building More information... More information... Back to “Select a building” Back to “Select a building” Project presentation (2...) A production facilities for windows fittings is attached to the back of the building. The building is located in a quiet industrial zone next to a low frequented road at the edge of a river. Noise and pollution are not a problem. Part under investigation

NatVent Presentation of the building Presentation of the building The design issue The design issue The building concept The building concept The winter monitoring The winter monitoring The summer monitoring The summer monitoring Major findings Major findings The VELUX building The VELUX building More information... More information... Back to “Select a building” Back to “Select a building” Project presentation (3...) Part under investigation Factory Cellular offices Open plan office

NatVent Presentation of the building Presentation of the building The design issue The design issue The building concept The building concept The winter monitoring The winter monitoring The summer monitoring The summer monitoring Major findings Major findings The VELUX building The VELUX building More information... More information... Back to “Select a building” Back to “Select a building” Project presentation (4...) 1 st floor The basement and the two lower floors consist of cellular offices.

NatVent Presentation of the building Presentation of the building The design issue The design issue The building concept The building concept The winter monitoring The winter monitoring The summer monitoring The summer monitoring Major findings Major findings The VELUX building The VELUX building More information... More information... Back to “Select a building” Back to “Select a building” Project presentation (5|) 3 rd floor The two top floors are designed as an open plan office (2 dn floor) and a show room (3 rd floor).

NatVent Presentation of the building Presentation of the building The design issue The design issue The building concept The building concept The winter monitoring The winter monitoring The summer monitoring The summer monitoring Major findings Major findings The VELUX building The VELUX building More information... More information... Back to “Select a building” Back to “Select a building” The design issue (1...) Windows furnished with electronic actuators As the building is used for the administration of a window fitting factory, window fixtures and fittings are seen as very important features by the occupants. Windows furnished with electronic actuators represent one of the new products of the company. The windows are automatically controlled with a manual override. This improves the user- acceptance.

NatVent Presentation of the building Presentation of the building The design issue The design issue The building concept The building concept The winter monitoring The winter monitoring The summer monitoring The summer monitoring Major findings Major findings The VELUX building The VELUX building More information... More information... Back to “Select a building” Back to “Select a building” The design issue (2|) To achieve the goals three control strategies were used: Automatically timer controlled system (e.g. for night ventilation and cross ventilation during the work breaks), Automatically opened windows depending on weather conditions (e.g. wind velocity, rain ). Manual operated system (The windows can also be manually controlled during working hours), The aim is for the occupants to get natural ventilation via the windows with electronic actuators. Thanks to the open architecture of the staircase of the building the stack effect is considered to provide a sufficiently strong force for ventilation. The aim is for the occupants to get natural ventilation via the windows with electronic actuators. Thanks to the open architecture of the staircase of the building the stack effect is considered to provide a sufficiently strong force for ventilation.

NatVent Presentation of the building Presentation of the building The design issue The design issue The building concept The building concept The winter monitoring The winter monitoring The summer monitoring The summer monitoring Major findings Major findings The VELUX building The VELUX building More information... More information... Back to “Select a building” Back to “Select a building” The building concept (1...) Indoor Air Quality during office hours Strategy for IAQ: During breaks (early in the morning and at noon) the windows are automatically (time controller) opened for 5 minutes to ventilate the building. During the heating season, the building is only ventilated during some periods to avoid too high ventilation losses Strategy for IAQ: During breaks (early in the morning and at noon) the windows are automatically (time controller) opened for 5 minutes to ventilate the building. During the heating season, the building is only ventilated during some periods to avoid too high ventilation losses

NatVent Presentation of the building Presentation of the building The design issue The design issue The building concept The building concept The winter monitoring The winter monitoring The summer monitoring The summer monitoring Major findings Major findings The VELUX building The VELUX building More information... More information... Back to “Select a building” Back to “Select a building” The building concept (2...) global strategy for summer comfort The risk of overheating is reduced by: Shading devices : external screens are installed on the all façades. The screens are controlled manually. The building and the thermal mass (exposed ceilings) of the building is cooled down by intensive ventilation based on the stack effect. The windows are automatically opened: during working hours in the afternoon if the outside temperature is higher than the inside temperature at night (time control) Moreover, the automatic control of the windows take weather conditions into account (see next slide...  ).

NatVent Presentation of the building Presentation of the building The design issue The design issue The building concept The building concept The winter monitoring The winter monitoring The summer monitoring The summer monitoring Major findings Major findings The VELUX building The VELUX building More information... More information... Back to “Select a building” Back to “Select a building” The building concept (3...) automatic control & outside conditions Ventilation control is a function of external conditions (see schematic). The outside conditions are measured by rain and wind sensors. closed always closed (security) open

NatVent Presentation of the building Presentation of the building The design issue The design issue The building concept The building concept The winter monitoring The winter monitoring The summer monitoring The summer monitoring Major findings Major findings The VELUX building The VELUX building More information... More information... Back to “Select a building” Back to “Select a building” The building concept (4...) overview SummertimeWintertime during office hours outside office hours  time- controlled short time ventilation during breaks - to improve IAQ  if T ext < T int : intensive ventilation (weather controlled) - to improve summer comfort intensive ventilation (weather controlled) - to improve summer comfort during office hours outside office hours  time- controlled short time ventilation during breaks - to improve IAQ no ventilation

NatVent Presentation of the building Presentation of the building The design issue The design issue The building concept The building concept The winter monitoring The winter monitoring The summer monitoring The summer monitoring Major findings Major findings The VELUX building The VELUX building More information... More information... Back to “Select a building” Back to “Select a building” The building concept (5|) user acceptance through independence during working hours All the automatically controlled windows can also be controlled manually (see control device). This permits the building users to operate the desired windows during the working hours in accordance with their required comfort. This increases the user acceptance of the system.

NatVent Presentation of the building Presentation of the building The design issue The design issue The building concept The building concept The winter monitoring The winter monitoring The summer monitoring The summer monitoring Major findings Major findings The VELUX building The VELUX building More information... More information... Back to “Select a building” Back to “Select a building” Slide with monitoring set-up Continuous measurements of Carbon Dioxide (CO 2 ), Ventilation Rate, Temperature Humidity, Indoor air velocity were made over one week periods during February 1997, August 1997, in the meeting room in the basement one cellular office on the ground floor two cellular offices on the first floor (south-west and north-east façade) one open plan on the second floor the show room on the third floor The cellular office on the first floor on the south-west building side was selected as being representative. The monitoring results of this office is shown in the following chart. Continuous measurements of Carbon Dioxide (CO 2 ), Ventilation Rate, Temperature Humidity, Indoor air velocity were made over one week periods during February 1997, August 1997, in the meeting room in the basement one cellular office on the ground floor two cellular offices on the first floor (south-west and north-east façade) one open plan on the second floor the show room on the third floor The cellular office on the first floor on the south-west building side was selected as being representative. The monitoring results of this office is shown in the following chart.

NatVent Presentation of the building Presentation of the building The design issue The design issue The building concept The building concept The winter monitoring The winter monitoring The summer monitoring The summer monitoring Major findings Major findings The VELUX building The VELUX building More information... More information... Back to “Select a building” Back to “Select a building” Winter monitoring (1...) typical winter day - monitoring results Indoor temperature sometimes too high due to problem with control of heating system Occupants open the windows because of too high temperatures  relatively high ventilation losses No ventilation at night = No ventilation losses

NatVent Presentation of the building Presentation of the building The design issue The design issue The building concept The building concept The winter monitoring The winter monitoring The summer monitoring The summer monitoring Major findings Major findings The VELUX building The VELUX building More information... More information... Back to “Select a building” Back to “Select a building” Winter monitoring (2...) typical winter day - monitoring results

NatVent Presentation of the building Presentation of the building The design issue The design issue The building concept The building concept The winter monitoring The winter monitoring The summer monitoring The summer monitoring Major findings Major findings The VELUX building The VELUX building More information... More information... Back to “Select a building” Back to “Select a building” Winter monitoring (3|) typical winter day - monitoring results Due to a problem with the control of the heating system, indoor temperatures were too high. For this reason windows were manually opened to cool the building. This leads to high ventilation losses. It is clear that a better heating control will result in a considerable reduction of the heating consumption in wintertime. At night all windows are well closed to avoid ventilation losses. The IAQ in the offices is always acceptable (<1200ppm).

NatVent Presentation of the building Presentation of the building The design issue The design issue The building concept The building concept The winter monitoring The winter monitoring The summer monitoring The summer monitoring Major findings Major findings The VELUX building The VELUX building More information... More information... Back to “Select a building” Back to “Select a building” Summer monitoring (1...) typical summer day - monitoring results Very warm day (34°C) Acceptable peak indoor temperature (28°C) Intensive night ventilation ( >10 ACH ) Indoor temperature drops due to night ventilation

NatVent Presentation of the building Presentation of the building The design issue The design issue The building concept The building concept The winter monitoring The winter monitoring The summer monitoring The summer monitoring Major findings Major findings The VELUX building The VELUX building More information... More information... Back to “Select a building” Back to “Select a building” = Windows are automatically opened at 8,13 and 18h to improve the IAQ. The other ventilation peaks are due to manually opened windows. The influence on the IAQ is given on next slide... Summer monitoring (2...) typical summer day - monitoring results Intensive night ventilation (>10 ACH)

NatVent Presentation of the building Presentation of the building The design issue The design issue The building concept The building concept The winter monitoring The winter monitoring The summer monitoring The summer monitoring Major findings Major findings The VELUX building The VELUX building More information... More information... Back to “Select a building” Back to “Select a building” Summer monitoring (3|) typical summer day - monitoring results There is a clear relation between IAQ during the office hours and the air change rate: High ventilation rate  low CO 2 concentration The IAQ is always below the limit of 1200 ppm

NatVent Presentation of the building Presentation of the building The design issue The design issue The building concept The building concept The winter monitoring The winter monitoring The summer monitoring The summer monitoring Major findings Major findings The VELUX building The VELUX building More information... More information... Back to “Select a building” Back to “Select a building” Major findings (1...) summer comfort Summer comfort: Thanks to the night ventilation and the shading devices, big overheating problems were avoided. Shading devices: The efficacy of the external screens could be increased by an automatic control instead of manual control. Night Cooling: For security reasons, windows on the ground floor are not opened at night  no night cooling. Therefore the offices on the ground floor have an appreciable overheating problem in summer. User behaviour: Closed doors during the night obstruct often the night cooling in summertime. Clear user instructions could help. A comparison of inside and outside temperature suggest that the night cooling effect could be used even more intensively by opening the windows at least 3 hours earlier.

NatVent Presentation of the building Presentation of the building The design issue The design issue The building concept The building concept The winter monitoring The winter monitoring The summer monitoring The summer monitoring Major findings Major findings The VELUX building The VELUX building More information... More information... Back to “Select a building” Back to “Select a building” Major findings (2...) summer comfort Night Cooling (optimisation of ventilation & stack effect): The openable area on each floor produced an unequal air change rate which resulted in a reduced night cooling effect and an increased risk on overheating for the upper floors. A better analysis of the relation between the opening surfaces and their height above the ground (analysis of the neutral level pressure) can increase the night cooling efficiency. Pressure diff. line BETTER...

NatVent Presentation of the building Presentation of the building The design issue The design issue The building concept The building concept The winter monitoring The winter monitoring The summer monitoring The summer monitoring Major findings Major findings The VELUX building The VELUX building More information... More information... Back to “Select a building” Back to “Select a building” In Winter: Due to problems with the controls for the heating system indoor temperatures were too high. Windows are opened to cool the building. This lead to unnecessary ventilation losses. In order to avoid ventilation due to overheating in winter, the heating supplied to the offices on the south-west building side should be reduced significantly especially in the sunny winter afternoons. The IAQ is acceptable In Summer: The IAQ is acceptable Major findings (3|) indoor air quality

More information... NatVent Presentation of the building Presentation of the building The design issue The design issue The building concept The building concept The winter monitoring The winter monitoring The summer monitoring The summer monitoring Major findings Major findings The VELUX building The VELUX building More information... More information... Back to “Select a building” Back to “Select a building” Find more information on the PROBE building in the following documents: \Reports \Monitoring Reports \Summary Reports\ch1summ.pdf global presentation of the buildings (  4p./building) contents: building description - ventilation strategy and technology - winter and summer monitoring results - conclusions \Reports \Monitoring Reports \Detailed Reports\ch1det.pdf detailed reports of all 19 monitoring campaigns (  20p./campaign) contents: monitoring set up - analysis of results - conclusions Find more information on the PROBE building in the following documents: \Reports \Monitoring Reports \Summary Reports\ch1summ.pdf global presentation of the buildings (  4p./building) contents: building description - ventilation strategy and technology - winter and summer monitoring results - conclusions \Reports \Monitoring Reports \Detailed Reports\ch1det.pdf detailed reports of all 19 monitoring campaigns (  20p./campaign) contents: monitoring set up - analysis of results - conclusions You can read and print pdf-files with the Acrobat® Reader ®3.0. Program. This program is free. Download it from the Acrobat web site: OR run the installation file ar32e301(1).exe in the directory \Installation You can read and print pdf-files with the Acrobat® Reader ®3.0. Program. This program is free. Download it from the Acrobat web site: OR run the installation file ar32e301(1).exe in the directory \Installation