Tax Office of Enschede S.H. Liem, A.H.C. van Paassen Delft, April 1998 S.H. Liem, A.H.C. van Paassen Delft, April 1998 Presentation of the building Presentation

Tax Office of EnschedeS.H. Liem, A.H.C. van Paassen

Delft, April 1998

S.H. Liem, A.H.C. van Paassen

Delft, April 1998

Presentation Presentation of the buildingof the building

Monitoring Monitoring set-upset-up

ConclusionsConclusions

Tax Office of Tax Office of EnschedeEnschede

More More information...information...

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Winter Winter monitoringmonitoring

Summer Summer monitoringmonitoring

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Building presentationBuilding presentationbackground informationbackground information

The Tax Office of Enschede was completed in 1996. It is located near the central railway station. It has offices on 5 floors and a total floor area of 4300 m2. The building is wedge shaped (see ground plan on next slide ...).

It is owned by the Government Building Agency.

Design: Architect: ir. Ruurd Roorda, Government Building Agency, NL. Daylight concept: Esbensen, DK. Energy concept & natural ventilation: W/E consultants, NL. Building physics: Peutz & Associes, NL.

This building is an EC2000 project, and is very energy efficient (17 m3/m2 gas equivalent of primary energy use) as a result of integrated design. The aim was to eliminate the need for mechanical ventilation and give occupant the maximum possible control of the indoor climate. Key issues are: optimal use of daylight, passive ventilation, cooling by night ventilation, low energy use and use of sustainable building materials.

The Tax Office of Enschede was completed in 1996. It is located near the central railway station. It has offices on 5 floors and a total floor area of 4300 m2. The building is wedge shaped (see ground plan on next slide ...).

It is owned by the Government Building Agency.

Design: Architect: ir. Ruurd Roorda, Government Building Agency, NL. Daylight concept: Esbensen, DK. Energy concept & natural ventilation: W/E consultants, NL. Building physics: Peutz & Associes, NL.

This building is an EC2000 project, and is very energy efficient (17 m3/m2 gas equivalent of primary energy use) as a result of integrated design. The aim was to eliminate the need for mechanical ventilation and give occupant the maximum possible control of the indoor climate. Key issues are: optimal use of daylight, passive ventilation, cooling by night ventilation, low energy use and use of sustainable building materials.

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Building presentationBuilding presentationtypical floor plan (1typical floor plan (1stst floor) floor)

Typical floor planTypical floor planTypical floor planTypical floor plan

N

Cellular offices

Cellular officesMeeting room

Meeting room

Cellular offices

Cellular offices

Storage of files

Storage of files

corridor

corridor

ATRIUM

Street + Railway

Str

eet

SquareConnection to old building

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Building presentationBuilding presentationcross section & view of the atriumcross section & view of the atrium

Cross sectionCross sectionCross sectionCross section

N

ATRIUMCellular office

Storage of files

Upward view of atriumUpward view of atriumUpward view of atriumUpward view of atrium

Internal solar protection

Internal solar protection

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Building presentationBuilding presentationview of the atrium & rear façadeview of the atrium & rear façade

Downward view of atriumDownward view of atriumDownward view of atriumDownward view of atrium

Rear façadeRear façadeRear façadeRear façade

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Building presentationBuilding presentationventilation installationventilation installation

Concept: The ventilation system is based on the stack effect of the atrium (see schematic on next slide ...).

Installation: Fresh air enters the building via

the trickle vents in the office.

The air passes to the atrium via acoustic ducts in the false ceiling.

The air leaves the building via the roof of the atrium (by natural means).

Fan-assisted:

If the wind velocity is less than 2 m/s, fans are switched on to help the stack effect in the atrium.

Concept: The ventilation system is based on the stack effect of the atrium (see schematic on next slide ...).

Installation: Fresh air enters the building via

the trickle vents in the office.

The air passes to the atrium via acoustic ducts in the false ceiling.

The air leaves the building via the roof of the atrium (by natural means).

Fan-assisted:

If the wind velocity is less than 2 m/s, fans are switched on to help the stack effect in the atrium.

Extraction chimneys Extraction chimneys on the roofon the roof

Extraction chimneys Extraction chimneys on the roofon the roof

Fans for suppl. Fans for suppl. ventilationventilation

Fans for suppl. Fans for suppl. ventilationventilation

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Building presentationBuilding presentationventilation concept - stack effectventilation concept - stack effect

Trickle vents

Acoustical ducts in false ceiling

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Building presentationventilation components

2 Trickle vents in 2 Trickle vents in each officeeach office

2 Trickle vents in 2 Trickle vents in each officeeach office

Extraction opening Extraction opening of the acoustic of the acoustic

duct in the officeduct in the office

Extraction opening Extraction opening of the acoustic of the acoustic

duct in the officeduct in the office

The settings of the The settings of the trickle vents are trickle vents are clearly marked: clearly marked:

0: all closed0: all closed

1: 1 open1: 1 open

2: 2 open2: 2 open

The settings of the The settings of the trickle vents are trickle vents are clearly marked: clearly marked:

0: all closed0: all closed

1: 1 open1: 1 open

2: 2 open2: 2 open

Remark: The trickle vents have very high acoustical performances (railway in

front of the building). They are also pressure

independent: within a certain range, they give the

same flow at different pressures (see next

slide...)

The two constant flow trickle vents are situated just below the exposed ceiling. The incoming cold air sticks to the ceiling by the Coanda effect and is mixed with the warm indoor air before it falls into the

office space, witch prevents draughts from causing comfort problems.

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Building presentationpressure independent vents

Pressure Pressure independent ventindependent vent

Pressure Pressure independent ventindependent vent

Pressure Pressure dependent ventdependent vent

Pressure Pressure dependent ventdependent vent

Pressure difference: p (Pa)

Flo

w Q

(m³/

h)

Q designQ designQ designQ design

Pressure difference rangePressure difference rangePressure difference rangePressure difference range

Pressure independent vents give a constant flow within a range of

pressure differences.

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Building presentationoffices

Besides the ventilation devices, the offices have other features which improve the indoor climate:

External blinds on the South façade to reduce the solar gains and avoid overheating.

A shelf beneath each window reflects the daylighting windows reflects the light deep in the room and so improves the light distribution. A high frequent light system keeps the light level at 500 lux.

The offices have a lot of exposed thermal mass in the ceilings and tiled floors. Therefore acoustic panels have been installed in the offices to reduce reverberation.

All these techniques are presented on the following schematic…

Besides the ventilation devices, the offices have other features which improve the indoor climate:

External blinds on the South façade to reduce the solar gains and avoid overheating.

A shelf beneath each window reflects the daylighting windows reflects the light deep in the room and so improves the light distribution. A high frequent light system keeps the light level at 500 lux.

The offices have a lot of exposed thermal mass in the ceilings and tiled floors. Therefore acoustic panels have been installed in the offices to reduce reverberation.

All these techniques are presented on the following schematic…

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Building presentationoffices

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Building presentationshading device on the South façade

External viewExternal viewExternal viewExternal view

Internal view - openInternal view - openInternal view - openInternal view - open Internal view - Internal view - closedclosed

Internal view - Internal view - closedclosed

Daylight shelf with integrated

lights

Daylight shelf with integrated

lights

Trickle vents

Trickle vents

Daylighting window

Daylighting window

Light shelves are automatically controlled by a solar radiation sensor, but it can be manually overruled

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Building presentationBuilding presentationthe building strategythe building strategy

A desk map gives very clear instructions to the occupants how to use the different devices in winter & summer (see next slide ...)

A desk map gives very clear instructions to the occupants how to use the different devices in winter & summer (see next slide ...)

In the winter: Ventilation:

during OH: position 1 (for Indoor Air Quality)

outside OH: position 0 (to reduce ventilation losses)

Heating: during OH: choose adequate

level outside OH: keep chosen level

Lighting during OH: on, if necessary outside OH: off

External shading: during OH: control freely outside OH: automatic control

In the winter: Ventilation:

during OH: position 1 (for Indoor Air Quality)

outside OH: position 0 (to reduce ventilation losses)





In the summer: Ventilation:

during OH: position 1 or 2 (for Indoor Air Quality & intens. vent.)

outside OH: position 2 (intensive night ventilation)





In the summer: Ventilation:

during OH: position 1 or 2 (for Indoor Air Quality & intens. vent.)

outside OH: position 2 (intensive night ventilation)





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WinterWinter

SummerSummer

During office hours

Outside office hours

During office hours

Outside office hours

ventilation

heating

lighting

External shading

Internal shading

Desk map with Desk map with user instructionsuser instructionsDesk map with Desk map with

user instructionsuser instructions

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Monitoringthe monitoring scheme - 1997

A winter (April) and summer (September) survey was organised.

In April the Coanda effect was determined in rooms 111, 121, 314, 320, 503 and 520; the CO2 levels were measured in rooms 105, 123, 505 and 518.

In June and July summer ventilation rates and CO2 levels were monitored in rooms 107, 122, 311, 322, 505 and 520.

The whole year the indoor temperature was monitored.

A winter (April) and summer (September) survey was organised.

In April the Coanda effect was determined in rooms 111, 121, 314, 320, 503 and 520; the CO2 levels were measured in rooms 105, 123, 505 and 518.

In June and July summer ventilation rates and CO2 levels were monitored in rooms 107, 122, 311, 322, 505 and 520.

The whole year the indoor temperature was monitored.

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Winter monitoringquestionnaires

170 questionnaires were distributed. 102 are returned. Of the respondents 20% are female and 80% male, the average age is 42 years.

Main results: They showed that temperatures in the offices were good, with enough

possibilities to control it. Air movement was reported to be either ‘adequate’ or ‘too high’.The

amount of control available to the occupants was either acceptable or good.

Air quality was ‘adequate’ and humidity either ‘good’ or to ‘low’. Unpleasant odours from cigarette , office equipment and diesel fumes

were considered to ‘acceptable’ by 75% of the respondents and ‘not’ acceptable by the remaining 25%.

96% are pleased with the daylighting, 58% complain about glare 99% have sufficient artificial light, 88% have control over the light

levels The noise level is ‘good’ to ‘satisfactory’ -10% of the interviewees

persons have problems with the noise.

170 questionnaires were distributed. 102 are returned. Of the respondents 20% are female and 80% male, the average age is 42 years.

Main results: They showed that temperatures in the offices were good, with enough

possibilities to control it. Air movement was reported to be either ‘adequate’ or ‘too high’.The

amount of control available to the occupants was either acceptable or good.

Air quality was ‘adequate’ and humidity either ‘good’ or to ‘low’. Unpleasant odours from cigarette , office equipment and diesel fumes

were considered to ‘acceptable’ by 75% of the respondents and ‘not’ acceptable by the remaining 25%.

96% are pleased with the daylighting, 58% complain about glare 99% have sufficient artificial light, 88% have control over the light

levels The noise level is ‘good’ to ‘satisfactory’ -10% of the interviewees

persons have problems with the noise.

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Room Façade Floor CoandaEffect

Distance[m]

111 South 1 yes 2.00121 North 1 Yes 2.00314 South 3 Yes 1.20320 North 3 Yes 1.50503 South 5 No -520 North 5 Yes 0.80

Courtesy W/E consultants

Winter monitoringthe Coanda effect

The Coanda effect causes the flow of cold air to stick to the ceiling for a long enough period for it to mix with the warm indoor air before it falls into the space below. This prevents discomfort from draughts.

The table below shows the number of times this phenomenon was detected and the distance travelled by the cold air before it fell into the space bellow.

The only room in which the Coanda effect was not noticeable was number 503 on the South façade of the 5th floor.

The Coanda effect causes the flow of cold air to stick to the ceiling for a long enough period for it to mix with the warm indoor air before it falls into the space below. This prevents discomfort from draughts.

The table below shows the number of times this phenomenon was detected and the distance travelled by the cold air before it fell into the space bellow.

The only room in which the Coanda effect was not noticeable was number 503 on the South façade of the 5th floor.

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Room Façade Floor Vent [m3/h]111 South 1 (160)121 North 1 (126)314 South 3 90320 North 3` 96503 South 5 110520 North 5 97

Courtesy W/E consultants

Winter monitoringventilation

In the winter only one trickle vent is open. The aim is to get a ventilation flow of 100 m3/h (2 ach).

The table below shows the results of experiments carried out on April 16 th. During the period monitored, the wind was from the North with a velocity of 2 m/s. The outdoor temperature was 10°C. These values are close to the design conditions for the building.

Air flow rates measured on the 3th and 5th floors are within 10% of each other; air flow rates on the 1st floor are rather high due to some construction problems. These problems have since been resolved.

In the winter only one trickle vent is open. The aim is to get a ventilation flow of 100 m3/h (2 ach).

The table below shows the results of experiments carried out on April 16 th. During the period monitored, the wind was from the North with a velocity of 2 m/s. The outdoor temperature was 10°C. These values are close to the design conditions for the building.

Air flow rates measured on the 3th and 5th floors are within 10% of each other; air flow rates on the 1st floor are rather high due to some construction problems. These problems have since been resolved.

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CO2 concentration level in April - during office hours

0

20

40

60

80

100

120

140

160

180

200

0- 300 300-600 600-900 900-1200 1200-1500 1500 and up

CO2 concentration level [ppm]

[ho

urs

]

Room 107 - S

Room 123 - N

Room 505 - S

Room 518 - N

Winter monitoringCO2 concentration level

The outdoor CO2 concentration level is 350 ppm. Values less than 350 ppm are due to the accuracy of the measurement apparatus that is used. The CO2 concentration levels found in the rooms are well below the maximum level of 1500 ppm; even CO2 concentration levels of 1200 ppm are very rare.

The outdoor CO2 concentration level is 350 ppm. Values less than 350 ppm are due to the accuracy of the measurement apparatus that is used. The CO2 concentration levels found in the rooms are well below the maximum level of 1500 ppm; even CO2 concentration levels of 1200 ppm are very rare.

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Summer monitoringquestionnaires

Of the 170 questionnaires that were distributed, 105 were returned. 19% of the respondents were female and 81% male, the average age was 42 years.

The survey was held in September, just after the ‘heat wave’ in August which clearly influenced the results.

Main results: The temperature on the workplace were ‘very hot ‘, control ‘bad’, very

little ventilation with ’bad’ ventilation control, although control of draughts was adequate.

The air quality is ‘satisfactory’ and the humidity ‘good’. 50% experience ‘smelly’ air, 60% blames this on the nearby railway

station; for 55% this was acceptable and for 45% not acceptable. 99% were ‘satisfied’ with the illumination, 3% wanted more light, 94%

could sufficiently control the day lighting, 35% had some problems with glare on their computer screen.

98% had sufficient electric light and can control it. Although the noise level was acceptable, 12% had problems with it.

Of the 170 questionnaires that were distributed, 105 were returned. 19% of the respondents were female and 81% male, the average age was 42 years.

The survey was held in September, just after the ‘heat wave’ in August which clearly influenced the results.

Main results: The temperature on the workplace were ‘very hot ‘, control ‘bad’, very

little ventilation with ’bad’ ventilation control, although control of draughts was adequate.

The air quality is ‘satisfactory’ and the humidity ‘good’. 50% experience ‘smelly’ air, 60% blames this on the nearby railway

station; for 55% this was acceptable and for 45% not acceptable. 99% were ‘satisfied’ with the illumination, 3% wanted more light, 94%

could sufficiently control the day lighting, 35% had some problems with glare on their computer screen.

98% had sufficient electric light and can control it. Although the noise level was acceptable, 12% had problems with it.

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Summer monitoringhot period in the summer

Due to the external venetian blinds on the south façade and the use of night cooling the internal temperatures are never higher than 28°C during a hot period (Text. = 32°C)

Due to the external venetian blinds on the south façade and the use of night cooling the internal temperatures are never higher than 28°C during a hot period (Text. = 32°C)

15

17

19

21

23

25

27

29

31

33

0:00 12:00 0:00 12:00 0:00 12:00 0:00 12:00 0:00

Time in hours / 11 to 14 August

Tem

per

atu

re [

°C]

Text.

Tatrium

T room123,NorthT room127, South

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Summer monitoringNight ventilation

The average long term ventilation flow during the last two weeks of July w has been determined in rooms 107, 122, 505 and 520 with the PFT-method.

A different tracer gas was used in each room. The gas concentration was measured at different locations in the rooms. Based on these results the ventilation rate was determined.

For night time ventilation cooling a minimum ventilation rate of 4 ach or 200

m3/h per room is required. The occupants are instructed to open both trickle vents when they go home (= setting 2).

The results are: The average summer night ventilation rate is 3.75 ach, the aim is 4 ach. The rooms are flushed very well; there are no ‘dead angles’ with higher

concentrations. Leaks between adjacent rooms are small (average 2 -8 m3/h, max. 40

m3/h in the lower floors and the N-room of the fifth floor).

The average long term ventilation flow during the last two weeks of July w has been determined in rooms 107, 122, 505 and 520 with the PFT-method.

A different tracer gas was used in each room. The gas concentration was measured at different locations in the rooms. Based on these results the ventilation rate was determined.

For night time ventilation cooling a minimum ventilation rate of 4 ach or 200

m3/h per room is required. The occupants are instructed to open both trickle vents when they go home (= setting 2).

The results are: The average summer night ventilation rate is 3.75 ach, the aim is 4 ach. The rooms are flushed very well; there are no ‘dead angles’ with higher

concentrations. Leaks between adjacent rooms are small (average 2 -8 m3/h, max. 40

m3/h in the lower floors and the N-room of the fifth floor).

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Summer monitoringCO2 concentration level

The CO2 concentration level during working hours in the summer were measured in June. These results differ not much from the CO2 level in the winter. The outdoor CO2 concentration level is 350 ppm. Values less than 350 ppm are due to the accuracy of the measurement instrument. The CO2 concentration levels found in the rooms are well below the maximum level of 1500 ppm.

The CO2 concentration level during working hours in the summer were measured in June. These results differ not much from the CO2 level in the winter. The outdoor CO2 concentration level is 350 ppm. Values less than 350 ppm are due to the accuracy of the measurement instrument. The CO2 concentration levels found in the rooms are well below the maximum level of 1500 ppm.

CO2 concentration level in June - during office hours

0

20

40

60

80

100

120

140

160

180

200

0- 300 300-600 600-900 900-1200 1200-1500 1500 and up

CO2 concentration [ppm]

[ho

urs

]

Room 107 - S

Room 123 - N

Room 505 - S

Room 518 - N

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Summer monitoringWeighted temperature exceeding hours

ISO 7730 describes a method for the evaluation of the internal summer comfort: This is the method of weighted exceeding hours. All hours with a temperature above 25°C are taken into account. High temperatures have a higher weighting factor:

Temperature weighting factor 25°C: 1.0 26°C: 1.4 27°C: 2.0 28°C: 2.6 29°C: 3.4 30°C: 4.2

The allowable norm weighted temperature exceeding is 150 degree hours.

ISO 7730 describes a method for the evaluation of the internal summer comfort: This is the method of weighted exceeding hours. All hours with a temperature above 25°C are taken into account. High temperatures have a higher weighting factor:

Temperature weighting factor 25°C: 1.0 26°C: 1.4 27°C: 2.0 28°C: 2.6 29°C: 3.4 30°C: 4.2

The allowable norm weighted temperature exceeding is 150 degree hours.

Based on the monitored indoor temperatures in 1997, 166 degree hours were calculated.

These results are not corrected for unintended accidents (opening the windows when it is very hot, cleaning the sun shades during hot summer days, operating the boiler, etc).

When corrected, the exceeding is 86 degree hours: the internal summer comfort can be considered as acceptable

Based on the monitored indoor temperatures in 1997, 166 degree hours were calculated.

These results are not corrected for unintended accidents (opening the windows when it is very hot, cleaning the sun shades during hot summer days, operating the boiler, etc).

When corrected, the exceeding is 86 degree hours: the internal summer comfort can be considered as acceptable

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Conclusions - 1 Natural ventilation:

The average winter ventilation rate is 2 ach, which was the design intention.

Summer night time ventilation rate is 3.75 ach. Indoor Air Quality: The CO2 levels in summer and winter are always

below the maximum value of 1500 ppm. IAQ is of an acceptable standard.

The Coanda effect was investigated and it was only in the most unfavourable room, situated on the fifth floor on the lee of the building that this phenomenon was not detected. In all the other rooms it functions well and there are no draught problems.

Overall conclusion:

the concept of natural ventilation with constant flow trickle vents, acoustic ducts to the atrium and auxiliary fans in the exhaust openings operates well.

Natural ventilation: The average winter ventilation rate is 2 ach, which was the design

intention. Summer night time ventilation rate is 3.75 ach. Indoor Air Quality: The CO2 levels in summer and winter are always

below the maximum value of 1500 ppm. IAQ is of an acceptable standard.

The Coanda effect was investigated and it was only in the most unfavourable room, situated on the fifth floor on the lee of the building that this phenomenon was not detected. In all the other rooms it functions well and there are no draught problems.

Overall conclusion:

the concept of natural ventilation with constant flow trickle vents, acoustic ducts to the atrium and auxiliary fans in the exhaust openings operates well.

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Cooling by natural ventilation (Night cooling) The ventilation rate for cooling (3,75 ach) is close to the desired value

of 4 ach. Higher cooling effects can be obtained if the auxiliary fans are switched on earlier.

Indoor temperatures are sometimes higher than would normally be the case because of operator error: (the boiler was switched on in the summer, several sunny days the sun shades were moved so that windows could be cleaned and windows were left open on days when outside temperature was higher than indoor temperature, etc.).

There were complains about summertime temperatures, but a heat wave in august had a significant influence on the findings.

The uncorrected weighted temperature exceeding is 166 hours for 1997 (an extreme hot year). This value is slightly higher than the limit value of 150 (for a normal year). However when one takes into account operating errors , the value can be lowered to 86 hours. Hence the summer comfort levels can be within acceptable limit if mistakes are avoided.

Cooling by natural ventilation (Night cooling) The ventilation rate for cooling (3,75 ach) is close to the desired value

of 4 ach. Higher cooling effects can be obtained if the auxiliary fans are switched on earlier.

Indoor temperatures are sometimes higher than would normally be the case because of operator error: (the boiler was switched on in the summer, several sunny days the sun shades were moved so that windows could be cleaned and windows were left open on days when outside temperature was higher than indoor temperature, etc.).

There were complains about summertime temperatures, but a heat wave in august had a significant influence on the findings.

The uncorrected weighted temperature exceeding is 166 hours for 1997 (an extreme hot year). This value is slightly higher than the limit value of 150 (for a normal year). However when one takes into account operating errors , the value can be lowered to 86 hours. Hence the summer comfort levels can be within acceptable limit if mistakes are avoided.

Conclusions - 2

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Concluding remarks

This concept shows that the integral approach of natural ventilation, effective solar shading, daylight control and the use of thermal mass for heat accumulation leads to a successful application of natural ventilation.

Concluding remarks

This concept shows that the integral approach of natural ventilation, effective solar shading, daylight control and the use of thermal mass for heat accumulation leads to a successful application of natural ventilation.

Concluding remarks and acknowledgement

Acknowledgement

We thank the Government Building Agency, East Directorate, Arnhem, NL, and W/E consultants sustainable building, Gouda, NL, who has performed the monitoring, to allow us to make use of the data (W/E report 5089.2, March 1998) and pictures.

Acknowledgement

We thank the Government Building Agency, East Directorate, Arnhem, NL, and W/E consultants sustainable building, Gouda, NL, who has performed the monitoring, to allow us to make use of the data (W/E report 5089.2, March 1998) and pictures.

More information...

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

\Reports \Monitoring Reports \Summary Reports\nl3summ.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\nl3det.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\nl3summ.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\nl3det.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

Documents

Tax Office of Enschede S.H. Liem, A.H.C. van Paassen Delft, April 1998 S.H. Liem, A.H.C. van Paassen Delft, April 1998 Presentation of the building Presentation