Field Mesurement Low Energy House Sisimiut

Contents 1.0 Field measurement ................................................................................................................................. 2 1.1

Report ........................................................................................................................................... 2

FIELD MEASUREMENT DTU JAN 2009 BRIAN HURUP‐FELBY, JONAS VENDEL JENSEN, THOMAS MONDRUP

1.0 Field measurement Throughout the study trip to Greenland a field measurement was made. The measurements included thermal measurements of the Energy House in Sisimiut. The task shall be seen as an additional task made together with Arctic Technology Centre DTU. Thus, the field measurements have no directly connection to the “actual project”.

Picture 1: Measuring the Energy House in Sisimius

1.1 Report In the following part the report handed in shortly after arriving from Greenland is presented. Thus, the layout of the report appears different.

2

FIELD MEASUREMENT OF THERMAL ENVIRONMENT AND VENTILATION RATE I N DO OR A IR Q UAL I TY A T THE ENE RG Y H O USE IN S IS I MIUT

By Brian Hurup‐Felby s958311, Jonas Vendel Jensen s020774 Thomas Mondrup s032483 DTU ‐ The 15th. Of January 2009

ABSTRACT To obtain the data in this experiment, we evaluate field measurements of thermal environment and ventilations rate in different rooms, measured on‐site at the Energy House in Sisimiut, enabling us to evaluate the air quality.

On the basis of the results a comparison of the thermal environment and indoor air quality of the different rooms are discussed and evaluated.

In general the measurements show coincident patterns in each case of the rooms. It can be seen that the ventilation and the air change rate appears to be essential regarding the indoor environment.

Further, the measurements emphasise the impact of mechanical ventilation on indoor environment.

INTRODUCTION Today many issues regarding the indoor air quality in various locations are being perceived as stuffy, smelly and unpleasant.

The indoor air quality is ordinarily determined by a concentration of bio effluents from human beings including person related CO2, tobacco smoke as well as degasification from

construction materials, furniture and other fixtures. Also the temperature and relative humidity play a role; where as a high relative humidity in rooms for instance can increase the chances of moulds etc.

Reducing the indoor sources of pollution by adapting the ventilation rate can be an important factor to controlling the indoor environment.

In this report the CO2 concentration, relative humidity and temperature are looked upon to evaluate the thermal environment and indoor air quality of different rooms at the Energy House.

OBJECTIVES The objectives of this experiment are: • •

To make a data collection of thermal parameters and ventilation rate To evaluate indoor environment on the basis of this data

METHODS The experiment and the additional measurements are being described and listed up in the following part.

INSTRUMENTS The experiment includes the use of following instruments: 1. HOBO data logger (1 unit)

2. VAISALA CO2 transmitter (1 unit) The HOBO data logger measures the air temperature and air humidity (every 1 minute). Furthermore, the logger is connected to the VAISALA CO2 transmitter which measures the CO2 concentration (every 1 minute).

different construction parts are described as the following: Floor (350 mm insulation) U = 0,14 W/m2K Walls (300 mm insulation) U = 0,15 W/m2K Ceiling (350 mm insulation) U = 0,13 W/m2K Windows (Energy) U = 1,00 W/m2K In the figure below the locations measured (three rooms) are pointed out.

Picture 1: HOBO Logger (U12‐012) [6]

The measuring range of the HOBO logger is given to be ‐20°C to +70°C (for temperature) and 5 to 95% RH (relative humidity) [6]. The CO2 transmitter measures from 0 to 2000 ppm CO2 [7].

Figure 1: Measuring points

The tables on the right display information and data for the three locations used in the experiment.

Table 1: Data for Room #1

Room #1

Picture 2: CO 2 Transmitter (GMW22) [7]

When measuring one must be aware of the placement of the HOBO data logger and CO2 transmitter, which must be kept in the occupant zone (middle of the room) in order to record useful and realistic data.

LOCATIONS FOR MEASUREMENTS The Energy House has a total size of 197 m2, divided into two separate apartments. The

Size / Occupants Site Dwelling Year build Heating Ventilation Windows

2700m³ / 1 Occupant Other dense populated area House 2005 Floor heating / Solar panels Natural ventilation Double glazing, U = 1,0 W/m2K

Table 2: Data for Room #2

Room #2 Size / Occupants Site Dwelling Year build Heating Ventilation Windows

2700m³ / 1 Occupant Other dense populated area House 2005 Floor heating / Solar panels Natural ventilation Double glazing, U = 1,0 W/m2K

Table 3: Data for Room #3

TIME DIFFERENCE

Room #3

Size / Occupants Site Dwelling Year build Heating Ventilation Windows

25600m³ / 3 Occupants Other dense populated area House 2005 Floor heating / Solar panels Natural ventilation Glazing (2+1), U = 1,0 W/m2K

The parameter dt is the difference in time, which is equivalent to t2‐t1. This value can be found by subtracting the end time and beginning time (see Figure 2) [3].

PROCEDURE One HOBO data logger and one CO2 transmitter is placed in each of the three rooms. Hence, the temperature, humidity and CO2 concentration is measured. When measuring CO2 you need a minimum measuring period of 24 hours. The measurements of the Energy House last for about one week – that is, five times the 24 hours.

Room #1 and Room #2 are used for sleeping.

The data collection of these rooms includes measurements of (in chronological sequence): 1. An empty room (daytime) 2. A room with one person sleeping (night) 3. An empty room (morning) [24 hours period from 12 am to 12 pm]

Room #3 is a traditional living room. The data of this room includes measurements of (in chronological sequence):

1. A room in use (daytime) 2. An empty room (night) 3. A room in use (morning) [24 hours period from 12 am to 12 pm] CALCULATIONS The CO2 measurements carried out in the experiment are further used to calculate the ventilation rate (the measurements do not directly produce the ventilation rate). The calculations are done on the basis of data from the decrease of the amount of CO2.

The calculation of the ventilation rate comprises the following steps:

dt = t 2 − t 1 t1, beginning time [h] t2, end time [h]

AIR EXCHANGE RATE To determine the ventilation rate the air exchange rate is needed. The air exchange rate can be determined by knowing the values of when the concentration starts to decrease until it is stopped. The following formula is being used [3]:

n=

ln( c (t 2 ) − ln( c (t1 ))

dt

n, air exchange rate [1/h] c(t1), tracer gas concentration, beginning [ppm] c(t2), tracer gas concentration, end [ppm] dt, time difference [h]

VENTILATION RATE

The ventilation rate can be calculated by knowing the air exchange rate, found previously, and the volume of the room.

Therefore, the ventilation rate is dependent on the air exchange rate [4].

q=

n⋅v

3,6

q = ventilation rate [l/s] v = volume [m3]

1 = converts from [m3/h] into [l/s] 3,6

RESULTS The following part shows the measured results; the temperature, relative humidity and CO2.

Below graphs of selected days are shown.

Again, the graphs illustrate measuring period of 24 hours to illustrate the progress of the entire day. Subsequently the maximum,

minimum and mean values are calculated and listed up (these values are based on data for the complete measuring period; approx 7 days).

Figure 2: Temp & RH Room #1

Figure 5: CO2 Room #1

Figure 3: Temp & RH Room #2 Figure 6: CO2 Room #2

Figure 4: Temp & RH Room #3

Figure 7: CO2 Room #3

Table 4: Temp (entire measuring period)

TEMP AND RH MEASUREMENTS

Room

Max Temp [°C]

Min Temp [°C]

Mean Temp [°C]

#1 #2 #3

24,10 27,58 25,74

15,56 18,91 20,82

21,66 23,14 23,73

Table 5: RH (entire measuring period) Room

Max RH [%]

Min RH [%]

Mean RH [%]

#1 #2 #3

60,25 47,09 44,88

32,02 26,55 29,26

43,55 36,38 36,52

Table 6: CO 2 (entire measuring period) Room

Max CO2 [PPM]

Min CO2 [PPM]

Mean CO2 [PPM]

#1 #2 #3

1758,00 1297,20 1015,20

622,00 515,10 534,80

877,18 629,28 651,44

On the basis of the formulas described earlier, the air change and ventilation rate is calculated. Results are listed in tables below.

Table 7: Calculations (selected day) Room #1 CO2 ‐ Increase CO2 ‐ Decrease Start [ppm]

659

End [ppm]

1634 (steady state)

695

Start time [s]

20:54:00

06:50:00

End time [s]

05:30:00

09:58:00

dt [s]

08:36:00

03:08:00

n [h ]

‐

0,46

q [l/s]

‐

3,43

‐1

1634 (steady state)

Table 8: Calculations (selected day) Room #2 CO2 ‐ Increase CO2 ‐ Decrease Start [ppm]

525

End [ppm]

1277 (steady state)

1277 (steady state)

592

Start time [s]

21:40:00

06:55:00

End time [s]

05:07:00

09:53:00

dt [s]

07:27:00

02:58:00

n [h ]

‐

0,51

q [l/s]

‐

3,84

‐1

Table 9: Calculations (selected day) Room #3 CO2 ‐ Increase CO2 ‐ Decrease Start [ppm]

555

778 (steady state)

End [ppm]

778 (steady state)

563

Start time [s]

21:40:00

06:13:00

End time [s]

03:13:00

07:48:00

dt [s]

05:33:00

01:35:00

n [h ]

‐

0,53

q [l/s]

‐

37,78

‐1

In the graphs it is shown that the fluctuations of the relative humidity follows the fluctuations of the CO2‐level. This most likely is because that the main contributor to the humidity is the respiration of the habitants.

In Room #3 (the living room) there is no remarkable deviation in the temperature nor the relative humidity.

In Table 4 it is shown that the highest temperature, a maximum value of 27,58°C, is measured in Room #2 (high temperatures may be due to the sun heating up the room). The lowest value, a minimum of 15,56°C, is measured in Room #1 (low temperatures may be caused by opening the window). The overall mean value is around 21°C to 23°C. Table 5 displays the relative humidity. Room #1 appears with the highest value, 60,25%, whereas Room #2 has the lowest, 26,55%. The overall mean value is around 36% to 43%.

Table 6 shows the levels of CO2. With a maximum of 1758,00 ppm Room #1 appears with the highest CO2‐level. Room #2 has the lowest, 515,10 ppm. The overall mean value is around 650 ppm to 870 ppm.

CO 2 MEASUREMENTS In Room #1 and Room #2 (the two bedrooms) the level of CO2 increase around 10 pm, when the user of the room goes to bed. The CO2 increases during the following hours until it becomes stable and reaches steady state. The CO2 then starts decreasing, depending on when the person is getting up, until it reaches a lower steady state. Before reaching lower steady state development of the graph for the CO2‐ level displays small fluctuations caused by morning activity.

Though there are no persons present, the CO2‐ level in Room #3 (the living room) also increases during the night. This might be due to that the transmitter measuring was placed close to Room #1 (bedroom).

AIR CHANGE AND VENTILATION All three rooms are calculated to have an air change rate around 0,5h‐1 (mechanical ventilation with heat recovery).

The ventilation rate in Room #1 and Room #2 is set to be around 3,5 l/s. Room #3 appears with a notable larger ventilation rate, 37 l/s (this is due to a larger volume).

DISCUSSION On the basis of the measurements and calculations carried out in the experiment, all the results are being further discussed. The results are being evaluated on the basis of European and Danish standards.

TEMP AND RH According to [1] for a residential building of Category II with a sedentary activity and a metabolic rate of 1,2 met, the temperature level must be between 20°C in the winter (minimum for heating) and 26°C in the summer (maximum for cooling). The mean temperature measured in the three rooms, spans from 21‐ 23°C, with only few deviations, which is being considered as a very steady and satisfying level.

In accordance with [1] a satisfying level of relative humidity in bedrooms is between 25‐ 60% (Category II).

In Room #1 and #2 (the two bedrooms) the humidity rises during the night. Only in Room #1 the humidity at some points exceeds the recommended limit of 60%, a maximum of 60,25%. Though, these values only appears momentary they are too high. However, the mean values vary from 36,38% to 43,55% which is considered as acceptable.

Because of a larger ventilation rate the relative humidity appears more stable in Room #3.

In the evening the lowest value of the relative humidity is present of 26,55% and is on the borderline of being to low, when comparing to [1]. However it does not constitute any risk of

dryness of mucous membranes according to P.O. Fanger [2].

When the relative humidity rises above 45% on a constant level (and a relatively low temperature) there is a risk of problems with dust mites and mould [1] [5]. On the basis of this Room #1 appears with a quite high relative humidity (mean value of 43,55%).

CO 2 The maximum values of CO2 in the three rooms are at 1758 ppm, 1297 ppm and 1015 ppm, respectively. According to [1] Category II allows a CO2‐level of 500 ppm above the outdoor level (measured to be 380 ppm). On the basis of [1] these values are too high.

However, the overall mean values in Room #1 and Room #2 ranges from 629,28 ppm to 877,18 ppm which is acceptable.

AIR CHANGE AND VENTILATION The mechanical controlled ventilation induces, compared to normal natural ventilation, an equal air change rate in all three rooms. The air change rate is calculated to be about 0.5h‐1 for all three rooms.

An air change rate of 0,5h‐1 produce a ventilation rate of 3,43 3,84 l/s per 1 person in Room #1 and #2. In Room #3 the values is calculated to be 37,78 l/s per 3 persons.

On the basis of relatively high levels of relative humidity and CO2 it can be discussed weather an air change rate of 0,5h‐1 is high enough.

Because of the Energy House being very tight, build with tight fittings etc., an increase of the air change rate could be an solution.

CONCLUSION In all three rooms the temperature was relatively constant during both day and night.

The relative humidity and the CO2 concentration though, both rose during night.

The highest humidity was measured to be 60,25%. The CO2 concentration rose from an outdoor level of 380 ppm up to 1758 ppm in the room with the highest level. According to

the standards this is too high. Meanwhile, the mean values appear acceptable.

With a value of 0,5h‐1 the air change rate is equal in all three rooms. However, the ventilation rate appears larger in Room #3 (compared to Room #1 and #2). Comparing the air change rate and ventilation rate, it is shown that the ventilation rate clearly depends on the size and use of the room.

In the light of the result of the measurements, a slightly higher air change rate is recommended.

A higher air change rate may lead to a better indoor environment with lower maximum values of both relative humidity and CO2.

REFERENCES [1] prEN15251: “Indoor environment input parameters for design and assessment of energy performance of buildings addressing indoor air quality, thermal environment, lightning and acoustics”, 31th July 2006

[2] Fanger, P.O.: “Air humidity, comfort and health”, DTU

[3] Persily K., Andrew: “Evaluating Building IAQ and Ventilation with Indoor Carbon Dioxide”, ASHRAE 1997

[4] D6245‐98: “Standard Guide for Using Indoor Carbon Dioxide Concentrations to Evaluate Indoor Air Quality and Ventilation”, 2002

[5] http://www.iprocessmart.com/techsmart/hu midity_why.htm

[6] http://www.onsetcomp.com/search/compare? nid[]=2233&nid[]=2248&nid[]=2252&nid[]=2 249&nid[]=2250&nid[]=2251&submit_button= Compare+Checked+Results

[7] http://www.esis.com.au/Vaisala/Vaisala.htm