CASE STUDY: NISKU PCL TEMPERATURE RECOVERY
Temperature profile recording at PCL Construction Resources, 2202 8th Street Nisku AB on the 7th of February 2005
- FUJI Model PHA98001-EB1YB Multichannel Inkject Strip Chart Recorder, s/n N3F5901-17B.
- Temperature Sensors: 6 x Type “T” Thermocouple.
- AIR BARRIER – ENERSHIELD Ultrashield US-192
Location of temperature sensors:
Three temperature sensors were located approximately 6 inches in front of the warehouse radiation, gas fired, heaters with the sole purpose of detecting the status of each heater.
One temperature sensor was located outside, at about 20 feet in front of the overhead door, where the air barrier system was located.
One temperature sensor was located indoor at about 6 feet from the overhead door, and about 4 feet above ground.
One temperature sensor was located to the centre of the warehouse and about 4 feet above ground.
The six recording channels were identified as follows:
Please see attached recording chart for details.
Recording chart speed: 240 mm/ Hr, (4 mm/ minute)
The thermostats controlling all three heaters were set at 15ºC.
In attendance to the test were, Chad Andrews, from PCL Construction Resources, Michael C. Launer and Ben Higgins, from Airplus Products Inc., and myself, Roberto Palomino from Accutech Rentals Ltd.
Recording chart interpretation:
At 9:11, according to the recorder clock, the recording of the above mentioned parameters started.
The Overhead door was closed and all the heaters off. The outdoor temperature was about -15ºC.
The two indoor temperature sensors showed a value around 21ºC.
Overhead door open, Air Barrier on, 60 min. test:
At 9:30 the overhead door was opened and the air barrier turned on for approximately 60 minutes.
At 9:36 heaters SE and SW ignited, two minutes later heater N. turned on.
During this period: all three heaters were on.
Outside temperature increased few degrees due mainly to the air flow from the air barrier affecting the sensor. The thermocouple was moved to the side away from the airflow.
The inside temperature by the door (INBYDOOR) dropped from 21ºC to about 13ºC while the one in the centre of the warehouse (INCENTR) dropped to about 12ºC.
First recovering time. 31 minutes.
At about 10:30 the overhead door was closed and the air barrier turned off.
The heaters kept going, the observed difference in the three heaters temperature curves is due the
cooling of the temperature sensing areas due to the air flow which the heaters were subject to.
Again, the profile of the heaters temperature curves is used only to show the status of the heaters, it is not intended to read an absolute value.
After the door was closed it took Heater N. 10 minutes to turn off, 16 minutes for Heater SW and 31 minutes for Heater SE, which could be considered full recovery period. At this time, indoor temperatures were back to around 20ºC.
Overhead door open, no air barrier, 60 minutes test.
At 11:12 the overhead door was open; four minutes later all three heaters came on and stayed on for the rest of the period.
“INBYDOOR” temperature dropped to an estimated average of -5ºC, reading a minimum of -10ºC and peak of 0ºC.
“INCENTR” temperature dropped to an estimate average of 3ºC, reading a minimum value, at the end of this period, of 2ºC.
Second recovery time, 110 minutes.
At 12:12 the overhead door was closed. All three heaters were still on. Heater N. shut off 46 minutes later, heater SW 52 minutes later and heater SE one hour and 41 minutes or a total of 105 minutes for a full recovery period.
It took one hour and 50minutes (110 min.) for the “INCENTR” temperature to go back to 20ºC.
To see specific details of the above, please see the recording chart.
The chart is divided in 100 small divisions, 10 major divisions for every tenth of the scale and 10 accentuated divisions reflecting the fifth of the scale and the related multiples.
For the heaters, scale is 1.5ºC/ small division and /or 15ºC/ major division.
For the temperature sensing channels (4, 5 and 6) is 0.6ºC/ small division and/ or 6ºC/ major division.