Monitoring of air temperature, humidity, and CO2 concentration

1. Monitoring of air temperature, humidity, and CO2 concentration

1.2.2017
Marianna Luoma
1

2. Monitoring excercise; instructions

Aim:
To learn to design, perform, and report a monitoring activity
Physical quantities to be measured:
Air temperature and relative humidity
Absolute humidity should be calculated
Optional: CO2 concentration
Alternative 1: Using data loggers for monitoring:
Data logger EBI 20, that should be programmed by means of a PC
Monitoring of air temperature and humidity
You should use at leat two data loggers
Alternative 2: Using a Grant squirrel multichanel data logger
Monitoring air and surface temperatures at 8 locations
The data logger is used together with a portable PC (available in the lab)
Sampling duration:
At least 24 hours
Groupwork:
One or two students in the group (monitoring of temperature and humidity)
Two students in the group (monitoring of temperature, humidity and CO2
concentration)

3. Optional

We will study air flow rates and CO2
concentarions later in this course
You could measure the air flow rates in the
room in which you do the monitoring,
however you need to learn how to measure
You could compare the measured air flow
rates to the design values in D2
If you monitor also CO2 concentrations, and
know the number of persons present, you
could do some further analysis of the
ventilation in the room
3

4. Example of monitoring in an office room * Think what kind of variation you could expect in temperature and humidity * Constant values are not very interesting results

°C
23
Lämpötila (°C)
Suhteellinen kosteus (%)
100
90
22,5
22
%
Mean air temperature 20,8 °C
Mean relative humidity 31 %RH
80
70
21,5
60
21
50
20,5
40
30
20
20
19,5
10
0
15:00
21:00
3:00
9:00
15:00
21:00
3:00
9:00
15:00
21:00
3:00
9:00
15:00
21:00
3:00
9:00
15:00
21:00
3:00
9:00
15:00
21:00
3:00
9:00
15:00
21:00
3:00
9:00
15:00
21:00
3:00
9:00
15:00
21:00
3:00
9:00
15:00
21:00
3:00
9:00
15:00
21:00
3:00
9:00
15:00
21:00
3:00
19
4

5. Memory capacity of the EBI 20 data loggers

8000 measured data (temperature and
humidity takes two)
The unit provides different recording modes
The desired recording mode is set by the PC
1.
2.
3.
4.
Endless measurement
Immediate measurement until memory is full
No measurement/start by pressing key
Start/stop measurement
5

6. Comparison of the two EBI 20 data loggers

The data loggers that you have, may show
different values for temperature and humidity
You should correct for that difference, when
you analyze your sampling data
This is how you should do:
When you are starting your sampling, put the
loggers first at the same location (at a table
side by side) and let them be there for an hour
Use this data to correct the results so that your
loggers show the same results at the same
location
6

7. Grant squirrel multichannel data logger

Each sensor has a long cabel
Suggestions for measuring activities:
Do a comparison of the sensors, since this
data logger is new and we do not yet have
information about its characteristics.
Study operative temperature, since one of the
sensors could be installed inside a globe
thermometer.
Study the efficiency of the heat recovery of
Building A by monitoring the temperatures in
various locations in the air handling unit.
7

8. Measuring CO2 concentarion

1050
0:07:00
0:37:00
1:07:00
1:37:00
2:07:00
2:37:00
3:07:00
3:37:00
4:07:00
4:37:00
5:07:00
5:37:00
6:07:00
6:37:00
7:07:00
7:37:00
8:07:00
8:37:00
9:07:00
9:37:00
10:07:00
10:37:00
11:07:00
11:37:00
12:07:00
12:37:00
13:07:00
13:37:00
14:07:00
14:37:00
15:07:00
15:37:00
16:07:00
16:37:00
17:07:00
17:37:00
18:07:00
18:37:00
19:07:00
19:37:00
20:07:00
20:37:00
21:07:00
21:37:00
22:07:00
22:37:00
23:07:00
23:37:00
0:07:00
Measuring CO2 concentarion
carbon dioxide level
1000
950
900
850
800
750
700
650
600
550
What are the resons for the variations?
8

9. Selecting the topics and reserving the instruments

Tuesday 7th of February:
Each group tells, what and where they are going to
monitor
Reserving the data loggers:
Send an e-mail to the laboratory engineer
[email protected] to reserve the loggers. Tell in
the e-mail about which instruments you need, when
you want to get the instruments and instructions to use
them, and when you will return them.
Save the monitoring results to your own memory stick
You need to do a PowerPoint file which has to be
returned on the 19th of March in Moodle (detailed
instructions for the report will be given later)

10.

Oral presentations
Presentations should be in a PowerPoint file
Oral presentations are held on Tuesday the
21st of February
The data should be shown in averages and in
graphs (done with Excel)
Absolute humidities should be calculated and
shown together with the air temperature and
relative humidity
CO2 concentrations should be shown
Photos of the monitoring are desirable
10

11. Suggestions for monitoring

Residence, indoor and outdoor conditions
Residence, conditions in different rooms
Residence, conditions at different heights
Conditions inside a refrigerator or freezer
Class room, conditions during the day, at different
heights or at different locations in the room
Something else that interests you? Swimming hall, gym,
department store…
Conditions inside a car
When you put the data logger outside, make sure
that it does not get wet (snow, rain…) or stolen.

12. Start with these questions:

With whom do you work?
The aim of the measurements?
When do you measure?
Where do you measure?
Which data loggers you are going to use?
How many loggers do you need?
For how long do you monitor? (at least 24
hours)
How often do you store the data (s, min, h)?
What kind of results do you expect to get?
How would you analyze the results?
Comparison of the reults to D2, standards
etc.?
12