USE OM - JANUARY 2017
59
5.2.6
Interpretation and Application of the Data
.
Specifically, this Thermal Energy Storage Effect Test is measuring
q
ts
and integrated thermal mass change in
temperature of the cyclic cooling or heating capacity per ASHRAE Standard 116 Section 9.2.2 to determine the
mc
pm
term.
5.2.6.1
Since Thermal Energy Storage Effect Test is being performed with electric heaters as
the source of capacity and electric heaters for all practical purposes are instantly
“on,” the “off” cycle
integrated capacity (Btu/h) is the measure of heat storage in the thermal mass. Therefore:
q
ts
= q
cyc,hoff
K11
5.2.6.2
The integrated change in temperature of the thermal mass, from the beginning of the
Thermal Energy Storage Effect test to the end of the six-minute
“on” cycle shall be considered thermal
storage potential.
5.2.6.3
Record the integrated cyclic single or multiple thermocouple average temperature,
representative of the bulk temperature of the largest thermal mass of the test equipment (usually the
mixer).
5.2.6.4
Determine mc
pm
from ASHRAE Standard 116 sections 7.4.3.4.5, and 9.2.2, for each
of the last 6 to 8 cycles.
mc
pm
= q
ts
/ [t
m
(0)
– t
m
(
Θ
I
)]
K12
5.2.6.5
Report mc
pm
as the mean of mc
pm
for last 6 to 8 cycles. Cycle equilibrium is defined in
ASHRAE 116 8.2.4.2 as three (3)
consecutive cycles in which the integrated ∆ T for the “on” portion of
the cycle does not vary by more than 0.3°F and the total watts for the complete
“on”/”off” cycle does
not very by more than 10 watts.
5.2.6.6
For
mc
pm
sufficiently low (4.0 Btu/°F or less), no adjustments to cyclic data is required.
For
mc
pm
greater than 4.0 Btu/°F, thermocouples shall remain on the device with the greatest thermal
energy storage effect and adjustment made to all cyclic Laboratory Certification Test as per ASHRAE
116 Section 9.2.2 and 9.2.3.
5.2.6.7
Example of data reporting.
Time
Stamp
(s)
Temp
Entering
Grid
(°F)
Temp
Leaving
Grid
(°F)
Air
Flow
(SCFM)
Specific
Heat
(BTU/lbm
da
-
°F)
Specific
Volume
(ft
3
/
lbm
da
)
Heater
Power
(W)
Air
Measured
Capacity
(Btu/h)
Mass Temp
(Btu/h-°R)
3590
70
90
1200
0.2405
0.075
8000
25974
90
3600
70
90
1200
0.2405
0.075
0
25974
89.9
3610
70
89.5
1200
0.2405
0.075
0
25325
89.8
3620
70
89
1200
0.2405
0.075
0
24675
89.7
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
7180
70
70.2
1200
0.2405
0.075
0
259
71.2
7190
70
70.1
1200
0.2405
0.075
0
129
71.0
Average
2435
