1. The EWZ building 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 EWZ building The EWZ building More information... More information... Back to “Select a building” Back to “Select a building” NatVent

2. 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 EWZ building The EWZ building More information... More information... Back to “Select a building” Back to “Select a building” The EWZ building was completed in 1994. The building is situated in the northern part of Zurich in an urban area. It is a five storey triangular shaped building, with two sides facing busy roads in a congested urban area. It is designed to protect the occupants from noise and air pollution. The façades provide a noise barrier and four atria are included (two on the north-side and two on the south-side) to provide maximum daylighting and natural ventilation. Thanks to its massive construction the building has a high thermal mass Project presentation (1...)

3. 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 EWZ building The EWZ building More information... More information... Back to “Select a building” Back to “Select a building” It is a five storey triangular shaped building, with two sides facing busy roads in a congested urban area. Project presentation (2...)

4. 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 EWZ building The EWZ building More information... More information... Back to “Select a building” Back to “Select a building” Mechanically ventilated offices Naturally ventilated offices Mechanically ventilated atria Project presentation (3|)

5. 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 EWZ building The EWZ building More information... More information... Back to “Select a building” Back to “Select a building” A two step hybrid ventilation concept was chosen to meet energy and comfort demands: The four atria are mechanically ventilated during the day, but provide manual window access to the surrounding offices which are naturally ventilated. At night time the atria and the offices are naturally ventilated. Decentralised ventilation units are used to reduce ductwork and energy use. The main target of this project was to design an energy efficient multi-use building, both in construction and in use. After completion of the building, the aim is to achieve further energy savings during operation together with good indoor environment. The design issue (1...)

6. 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 EWZ building The EWZ building More information... More information... Back to “Select a building” Back to “Select a building” The design issue (2|)

7. 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 EWZ building The EWZ building More information... More information... Back to “Select a building” Back to “Select a building” The building concept (1...) ventilation strategy during summer Offices Atria … for the Atria: During working hours: Mechanical ventilation with heat recovery and central cooling. At night: Natural ventilation by window opening in the atria. … for the Offices : Natural ventilation by manual opening the windows facing the atria. … for the Atria: During working hours: Mechanical ventilation with heat recovery and central cooling. At night: Natural ventilation by window opening in the atria. … for the Offices : Natural ventilation by manual opening the windows facing the atria.

8. 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 EWZ building The EWZ building More information... More information... Back to “Select a building” Back to “Select a building” The mechanical ventilation system is equipped with a central heat recovery unit to reduce the energy losses during the heating season. Moreover, the ventilation is turned off outside office hours Heat Recovery Unit Exhaust Air Supply Air Fresh Air The building concept (2...) low energy use in winter time

9. 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 EWZ building The EWZ building More information... More information... Back to “Select a building” Back to “Select a building” Ice stack is loaded during the night to cool during the day. The atria are then ventilated, with a projected air exchange rate of 5 h -1 (pre-cooled air at 16 to 17°C). To properly mix the air in the atria ventilators are installed. In addition night cooling is applied by automatically opening the top windows in the atria. To reduce solar impact there are motorised shading devices (external screens) on the side walls and atria roofs. There is no active cooling in the offices ! (Schematic - see next slide…  ) The building concept (3...) overall strategy for summer comfort

10. 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 EWZ building The EWZ building More information... More information... Back to “Select a building” Back to “Select a building” External screens NightDay Ice stack load Night Cooling Mixing Fans Cooled Air (Outside air is pre-cooled by the Ice stack load: 16 to 17°C) The building concept (4...) overall strategy for summer comfort

11. 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 EWZ building The EWZ building More information... More information... Back to “Select a building” Back to “Select a building” The ventilation concept was chosen to meet comfort demands. Concept: The atria is mechanically ventilated and provides manual window access to the surrounding offices which are naturally ventilated. Control: The air change rate in the office is chosen by the users as they wish. NatVent Offices Atria The building concept (5|) indoor air quality during office hours

12. 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 EWZ building The EWZ building More information... More information... Back to “Select a building” Back to “Select a building” Monitoring set-up Continuous measurements of carbon dioxide (CO 2 ) / ventilation rate / temperature / humidity / indoor air velocity (in the offices) were made over one week periods during February 1997, July 1997, in atrium 2 (right side of the south façade of the building) three cellular offices on the first, second fourth floor of the atrium 2 (fully monitored) atrium 1 (left side of the south façade of the building) three cellular offices on the first, second fourth floor of the atrium 2 (only temperature) The following offices were considered as representative: for winter: a cellular office on the second floor surrounding atrium 2 for summer: a cellular office on the first floor surrounding atrium 2. The monitoring results of these offices are shown in the following charts Continuous measurements of carbon dioxide (CO 2 ) / ventilation rate / temperature / humidity / indoor air velocity (in the offices) were made over one week periods during February 1997, July 1997, in atrium 2 (right side of the south façade of the building) three cellular offices on the first, second fourth floor of the atrium 2 (fully monitored) atrium 1 (left side of the south façade of the building) three cellular offices on the first, second fourth floor of the atrium 2 (only temperature) The following offices were considered as representative: for winter: a cellular office on the second floor surrounding atrium 2 for summer: a cellular office on the first floor surrounding atrium 2. The monitoring results of these offices are shown in the following charts

13. 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 EWZ building The EWZ building More information... More information... Back to “Select a building” Back to “Select a building” Winter monitoring (1...) typical winter day - monitoring results Slight overheating in offices due to problems with automatic control of the shading devices

14. 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 EWZ building The EWZ building More information... More information... Back to “Select a building” Back to “Select a building” Winter monitoring (2...) typical winter day - monitoring results Good IAQ: low CO 2 concentration during office hours (far below 1200 ppm)

15. 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 EWZ building The EWZ building More information... More information... Back to “Select a building” Back to “Select a building” Winter monitoring (3|) typical winter day - monitoring results Low air change rate is sufficient: good air quality

16. 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 EWZ building The EWZ building More information... More information... Back to “Select a building” Back to “Select a building” Summer monitoring (1...) typical summer day - monitoring results Good thermal comfort in office: T int = 23°C while T ext goes to 33°C: Remark: This results is partially the result of active cooling in the atrium

17. 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 EWZ building The EWZ building More information... More information... Back to “Select a building” Back to “Select a building” Summer monitoring (2...) typical summer day - monitoring results Good IAQ: low CO 2 concentration during office hours (far below 1200 ppm)

18. 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 EWZ building The EWZ building More information... More information... Back to “Select a building” Back to “Select a building” Summer monitoring (3|) typical summer day - monitoring results Air change rates are sufficient  good IAQ However no ventilation during the night to cool the office: window is closed

19. 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 EWZ building The EWZ building More information... More information... Back to “Select a building” Back to “Select a building” Night Cooling of the atria: Thanks to the architecture the stack effect in the atria can be considered to provide a sufficiently strong force for natural ventilation; On the other hand a re-evaluation of the dimensions of the openings could increase night ventilation resulting in a better natural night cooling. Night Cooling of the offices - Barriers Night cooling in the atria only takes place if atria windows are open. The atria windows are in this case automatically open if outside temperature is three degrees lower than the air temperature in the atria (this a typical strategy for mechanical night cooling). For natural night cooling the atria windows should automatically open if outside temperature is lower than the air temperature in the atria Night cooling in the offices only takes place if the office windows have been left open after the end of the working days. Closed office windows and doors form a large obstruction for the natural night cooling. The best night cooling efficiency is achieved by cross ventilation through window and door. Major findings (1...)

20. 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 EWZ building The EWZ building More information... More information... Back to “Select a building” Back to “Select a building” Shading devices: In the winter, the shading devices, which close automatically, did not close at the right time. Therefore offices are sometimes lightly overheated and illuminated with too much direct sun light. The automatically shading devices in summer achieved the expected aims. The thermal comfort in summertime is optimal (remark: in summer active cooling is used in the atria). The Indoor Air Quality is always acceptable Occupant Reactions: The occupants are very satisfied with the building.One of the main reasons is that they appreciate being able to open the windows. Major findings (2...)

21. 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 EWZ building The EWZ building More information... More information... Back to “Select a building” Back to “Select a building” In General: The EWZ building is a good example of a pragmatic approach. The hybrid concept combines active cooling and passive elements like night cooling and shading devices. The concept provides high quality indoor comfort at any external condition. Energy consumption: The EWZ building can be considered as a building with a rather low energy consumption. A further reduction of the energy consumption can be achieved by an optimisation of the heating level in winter and the electricity consumption for the cooling and for the mechanical ventilation. Major findings (3|)

22. 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 EWZ building The EWZ 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\ch2summ.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\ch2det.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\ch2summ.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\ch2det.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: www.adobe.com 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: www.adobe.com OR run the installation file ar32e301(1).exe in the directory \Installation