NatVent - BREprojects.bre.co.uk/natvent/presentation/207_dk1.pdf · Indoor (average of 4 offices) &...

Architect: KHR A/SArchitect: KHR A/S

E.Phil & Son AS headquarters

NatVent

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PresentationPresentationof the buildingof the building

VentilationVentilationstrategy &strategy &technologytechnology

ConclusionsConclusions

E. E. PihlPihl & Son AS & Son ASBuildingBuilding

MoreMoreinformation...information...

SummerSummermonitoringmonitoring

WinterWintermonitoringmonitoring

MonitoringMonitoringset-upset-up

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Building Presentation (1...)

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! E. Pihl & Son is a major contractor in Denmark.! The company Headquarters is located in Lyngby, about 10 kilometres

north of Copenhagen City in a suburban environment.! The office building was completed in 1993/94.

! The building is a three-storey office building.! The building is angled in a diagonal symmetry.! The corridors are sky-lit galleries.! The building is specifically designed for natural ventilation.! The facade of the building is brickwork and glass while the roof and the

internal walls are in situ concrete.

! The floor area is about 2.700 m2" 2.000 m2 (75%) is offices and meeting rooms" 400 m2 (15%) is circulation area" 200 m2 is canteen and 100 m2 is toilets and cloakrooms

Building presentation (2...)

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CanteenCanteen

2-storey foyer2-storey foyerOffice wing, north-Office wing, north-

west facadewest facade

Building presentation (3...)

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N

Building presentation (4...)typical floor plan

Corridors with skylightsCorridors with skylights

CanteenCanteen

Two-storey foyerTwo-storey foyerwith glazed facadewith glazed facade

Main entranceMain entrance

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Building presentation (5|)internal view

! Generally the internal concrete walls and ceilings are exposed. Thethermal mass of the building can be characterised as heavy.

! Internal steel frames support stairways, skylights, fittings and otherpermanent furnishings

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E. Pihl & Son required an office building of high quality and the technicalinstallations should be simple and hidden yet effective and advanced.

The building is specifically designed for natural ventilation. In the designstage for the ventilation the architects and engineers took into account:

" not only the thermally generated pressures," but also the wind induced pressures.

Knowledge and ideas from traditional buildings in the tropics were taken intoconsideration including the principles developed for the Danish pavilion atthe Sevilla fair.

Ventilation strategy & aims (1...)

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Ventilation strategy (2...)for summer comfort

! In summertime the risk of overheating is reduced by intensive ventilation:" The intensive ventilation is completely natural and is based on the

opening of windows in the façade. Mechanical ventilation is only used inthe meeting rooms, toilets, canteen and main foyer

" The windows are partly controlled mechanically and partlycontrolled automatically.

" The intensive ventilation of the offices is based on cross ventilationand single sided ventilation (when the internal doors are closed).

" Under certain conditions the vertical skylights open automatically. Inwhich case stack effects are one of the driving natural forces.

" During periods when stack effects are not strong enough to drive thenatural ventilation regime , two extraction fans on the roof are turnedon. Under extreme conditions, the system is fan-assisted.

! The solar gains are reduced to a certain degree by the use of internalblinds.

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Ventilation strategy (3...)for summer comfort

The ordinary windows inthe offices are manuallycontrolled. The windowsmust be closed duringnight-time due to securityreasons.

Vertical openings inthe skylights and ...

Roof fans are automatically activatedat an internal temperature of 26 °Cmeasured in the two-storey foyer

…ventilation openingslocated in narrow windowbands above the ordinarywindows in the officesare equipped withelectronic actuators. Theopenings can be leftopen during night-time.

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Ventilation strategy (4...)for indoor air quality

! The indoor air quality during theoffice hours in winter and summertime is controlled by the occupants:" Occupants can improve the air

quality by opening thewindows.

" There is no automatic controlrelated to the IAQ.

Manually controlledManually controlledopenable openable windowswindows

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Ventilation devices - OFFICES:specially designed multi-position ventilation openings:" located in narrow window bands above the ordinary windows" motorised for manual and automatic control

Ventilation devices - CORRIDORS:openable skylights:" motorised for both manual and automatic controltwo extract fans located on the roof" integrated with the skylights" intended for use in case the natural driving forces are insufficient

The control system (I-BUS, “intelligent house”) controls:" the ventilation openings" the heating system" the artificial lighting" the solar shading

Ventilation technology (5...)

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High positioned, motorisedHigh positioned, motorisedventilation openings...ventilation openings...

Ventilation technology (6...)open plan office

…located in narrow window bands…located in narrow window bandsabove the ordinary windowsabove the ordinary windows

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In the offices, internal solarIn the offices, internal solarshading is motorised aluminiumshading is motorised aluminium

blindsblinds

Ventilation technology (7...)single office

Most offices facing north-westMost offices facing north-westhave large highly glazedhave large highly glazedfacades.facades.

Motorised ventilation openings ...Motorised ventilation openings ...

… and manually controlled… and manually controlledopenable openable windowswindows

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Vertical skylight in theVertical skylight in theopen position (~45open position (~45°°°°°°°°))

One of two extract fansOne of two extract fanslocated on the rooflocated on the roof

Ventilation technology (8|)corridors

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Monitoring set-upN

Office 1

Office 2

Office 5

Office 3Office 4

Office 1

Office 2

Office 3

Office 5

Investigated offices:Five offices on the second floor werechosen for the monitoring" Office 1: 20 m2 cellular office" Office 2:" Office 3: 14 m2 each" Office 4:" Office 5: 16 m2, 2 persons

Office 4

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0

5

1 0

1 5

2 0

2 5

3 0

3 5

Mon

07.

07.9

7

Mon

14.

07.9

7

Mon

21.

07.9

7

Mon

28.

07.9

7

Mon

04.

08.9

7

Mon

11.

08.9

7

Mon

18.

08.9

7

Mon

25.

08.9

7

Mon

01.

09.9

7

Mon

08.

09.9

7

Mon

15.

09.9

7

Mon

22.

09.9

7

Mon

29.

09.9

7

Tem

pera

ture

[°C

]

Summer monitoring (1...)Indoor (average of 4 offices) & outdoor

temperatures during a three months period

Text.

Tint.

The internal temperatures is often > 25°C and even > 28°C,while the external temperature is far much lower.

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0

5

10

15

20

25

30

Fri 1

8.07

.97

Sat 1

9.07

.97

Sun

20.0

7.97

Mon

21.

07.9

7

Tue

22.0

7.97

Wed

23.

07.9

7

Thu

24.0

7.97

Fri 2

5.07

.97

Sat 2

6.07

.97

Tem

pera

ture

[°C

], Ai

r sup

ply

[l·s-1

·m-2

]

Summer monitoring (2...)measurements in office 1

Tint.

Air Supply

= Intensive night ventilation ( up to 15 l/s.m²).

Text.

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0

1 0

2 0

3 0

4 0

5 0

18.0

7.97

19.0

7.97

20.0

7.97

21.0

7.97

22.0

7.97

23.0

7.97

24.0

7.97

25.0

7.97

26.0

7.97

Tem

pera

ture

[°C

], Ai

r sup

ply

[l·s-1

·m-2

]

0

1 0 0

2 0 0

3 0 0

4 0 0

5 0 0

CO

2 con

cent

ratio

n [p

pm]

Summer monitoring (3...)results of measurements in office 1

Tint.

CO2-conc.

Air Supply

The IAQ during the office hours is good: The CO2-concentrations arevery low: max.450 ppm (= far below the limit concentration of1200ppm) due to the quite high air supply (intensive ventilation).

During the weekend the internalCO2-concentration equals theoutdoor CO2-conc: no occupation.

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In addition to the measurements, the occupants filled in two questionnairesconcerning their views on various environmental conditions in theiroffice. One questionnaire concerned the summer season in generaland the other concerned one week in particular (in the summerseason), namely the one in which the questionnaires were handed out.

Each occupant indicated his/her rating of each of the conditions(temperature, air movement etc.) by placing vertical marks ondimensionless, horizontal lines of equal length ranging from mostpositive (comfortable, fresh etc.) to most negative (uncomfortable,stuffy etc.). The rating is quantified by measuring (in millimetres) thedistance along each line from most positive to the occupant’s mark.For practical purposes, the ratings have been converted into the range0-100.

The next slide summarises the ratings concerning the summer season ingeneral.

Summer monitoring (4…)Questionnaires

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42

41

42

26

29

25

54

39

0 20 40 60 80 100

Temperature

Air movement

Air quality

Odour intensity

Acceptability

Light

Noise

Overall comfort

Comfortable

Fresh

Comfortable

Uncomfortable

Uncomfortable

Stuffy

Satisfactory

Satisfactory

Satisfactory

Unsatisfactory

Unsatisfactory

Unsatisfactory

Odourless Smelly

Acceptable Not acceptable

Temperature

Air movement

Air quality

Odour intensity

Acceptability

Light

Noise

Overall comfort

Averages of about 50 occupants ratings of various environmental conditionsin their office during working hours.

Summer monitoring (5...)Questionnaires

Due tointernal noise

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! Thermal comfort in summer:Despite the intensive ventilation, internal temperatures are often toohigh (>28°C). This problem is due to:

" Large solar gains: the building has large glazed areas and limitedshading device (internal blinds)

" Problems with the control system were encountered. Mostproblematic was it, that the automatic opening of both theskylights and the vents in the offices was unreliable, leading to aninefficient night-time cooling effect and hence, elevatedtemperatures in the offices from early morning.

Summer monitoring (6...)Findings

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! Thermal comfort in summer:… However, the occupants expressed only limited dissatisfactionwith the thermal environment. Presumably, the occupantsthemselves, together with the manager in charge of the technicalinstallations, were able to manually control both the ventilationopenings and the internal blinds and thereby quickly obtainacceptable conditions. High internal air velocities can partlycompensate for the high indoor temperature. The high level of usersatisfaction is attributable to the availability of manuals controls.

! Indoor Air Quality:The IAQ can be considered as good:The measured CO2 - concentrations are low.

Summer monitoring (7|)Findings

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-5

0

5

1 0

1 5

2 0

2 5

3 0

Mon

10.

11.9

7

Mon

17.

11.9

7

Mon

24.

11.9

7

Mon

01.

12.9

7

Mon

08.

12.9

7

Mon

15.

12.9

7

Mon

22.

12.9

7

Mon

29.

12.9

7

Mon

05.

01.9

8

Tem

pera

ture

[°C

]

Winter monitoring (1...)Indoor (average of 4 offices) & outdoor

temperatures during a two months period

Text.

Tint.

The internal temperature is comfortable(21°C-23°C). During the weekends theheating power is reduced.

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0

2 0 0

4 0 0

6 0 0

8 0 0

1 0 0 0

1 2 0 0

Wed

26.

11.9

7

Thu

27.1

1.97

Fri 2

8.11

.97

Sat 2

9.11

.97

Sun

30.1

1.97

Mon

01.

12.9

7

Tue

02.1

2.97

Wed

03.

12.9

7

Thu

04.1

2.97

Fri 0

5.12

.97

Sat 0

6.12

.97

Sun

07.1

2.97

Mon

08.

12.9

7

Tue

09.1

2.97

CO

2 con

cent

ratio

n [p

pm]

CO2 concentration outdoor and indoor. Indoor CO2 is averaged fromrecordings taken simultaneously in office 3, 4 and 5.

Winter monitoring (2...)CO2 concentration

OutdoorCO2-conc.

IndoorCO2-conc.

The IAQ during the office hours is good:The CO2-concentrations are below thelimit concentration of 1200ppm.

During the weekend the internalCO2-concentration equals theoutdoor CO2-concentration

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0

1 0

2 0

3 0

4 0

5 0

Wed

26.

11.9

7

Thu

27.1

1.97

Fri 2

8.11

.97

Sat 2

9.11

.97

Sun

30.1

1.97

Mon

01.

12.9

7

Tue

02.1

2.97

Wed

03.

12.9

7

Thu

04.1

2.97

Fri 0

5.12

.97

Sat 0

6.12

.97

Sun

07.1

2.97

Mon

08.

12.9

7

Tue

09.1

2.97

Tem

pera

ture

[°C

], Ai

r sup

ply

[l·s-

1 ·m-2

]

0

2 0 0

4 0 0

6 0 0

8 0 0

1 0 0 0

CO

2 con

cent

ratio

n [p

pm]

Winter monitoring (3...)results of measurements in office 5

Limited air supply,to control the IAQ

The IAQ during the office hours is acceptable:The indoor CO2 -concentrations are below thelimit concentration of 1200ppm.

OutdoorCO2-conc.

IndoorCO2-conc.

Air supply

During the weekend the airsupply could be more limited,to reduce the energy losses

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Winter monitoring (4...)Questionnaires

In addition to the measurements, the occupants filled in two questionnairesconcerning their views on various environmental conditions in theiroffice. One questionnaire concerned the winter season in generaland the other concerned one week in particular (in the winterseason), namely the one in which the questionnaires were handed out.

Each occupant indicated his/her rating of each of the conditions(temperature, air movement etc.) by placing vertical marks ondimensionless, horizontal lines of equal length ranging from mostpositive (comfortable, fresh etc.) to most negative (uncomfortable,stuffy etc.). The rating is quantified by measuring (in millimetres) thedistance along each line from most positive to the occupant’s mark.For practical purposes, the ratings have been converted into the range0-100.

The next slide summarises the ratings concerning the winter season ingeneral.

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Averages of about 75 occupants ratings of various environmental conditionsin their office during working hours:

26

33

35

28

26

22

43

32

0 20 40 60 80 100

Tem perature

Air m ovem ent

Air quality

Odour intensity

Acceptability

Light

Noise

Overall com fort

Com fortable

Fresh

Com fortable

Uncom fortable

Uncom fortable

Stuffy

Satisfactory

Satisfactory

Satisfactory

Unsatisfactory

Unsatisfactory

Unsatisfactory

Odourless Sm elly

Acceptable Not acceptable

Temperature

Air movement

Air quality

Odour intensity

Acceptability

Light

Noise

Overall comfort

Winter monitoring (5...)Questionnaires

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! Winter indoor conditions are comfortable" During occupancy period the indoor temperature in the offices is

between 21 and 23 ºC, the CO2 concentration is about 800-1000ppm and outdoor supply equals air change rates of about 2-5times per hour.

" During weekends and out of office hours the indoortemperature drops to about 20 ºC, the CO2 concentration to nearbackground level (400 ppm) and the air supply to close to zero.However the energy consumption can be optimised by reducingthe ventilation losses during the weekends.

! The indications are that the occupants found the indoor environment tobe more comfortable during the winter-time than in the summer-time. Inthe summer-time, the thermal comfort is more critical than during thewinter.

Winter monitoring (6|)Findings

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Conclusions (1...)Findings from summer monitoringThermal summer comfort:

Despite the high ventilation levels, internal temperatures arefrequently too high (>28°C). This problem is due to:

" Large solar gains: the building has large glazed areas and limitedshading device (internal blinds)

" Problems with the control system were encountered. Mostproblematic was it, that the automatic opening of both theskylights and the vents in the offices was unreliable, leading to aninefficient night-time cooling effect and hence, elevatedtemperatures in the offices from early morning.

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Conclusions (2|)Findings from winter monitoring

! Winter indoor conditions are comfortable" During occupancy period the indoor temperature in the offices is

between 21 and 23 ºC, the CO2 concentration is about 800-1000 ppmand fresh air supplies between 2 and 5 air changes per hour.

" During weekends and out of office hours the indoor temperaturedrops to about 20 ºC, the CO2 concentration to near background level(400 ppm) and the air supply to close to zero. However the energyconsumption can be optimised by reducing the ventilation lossesduring the weekends.

! The indications are that the occupants found the indoor environment to bemore comfortable during the winter-time than in the summer-time.In thesummer-time, thermal comfort is more critical than during the winter.

More information...

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Find more information on the PROBE building in the following documents:

\Reports \Monitoring Reports \Summary Reports\dk1summ.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\dk1det.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 ORrun the installation file ar32e301(1).exe in the directory\Installation

NatVent - BREprojects.bre.co.uk/natvent/presentation/207_dk1.pdf · Indoor (average of 4 offices) &...

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