104AT-2 Semitec, 104AT-2 Datasheet - Page 19

• Manufacturer Part Number: 104AT-2
• Description: AT thermistor, 100KOhm
• Manufacturer: Semitec

FD SENSOR
1. Application
The FD Sensor has been developed to detect the level of accumulated frost
on the evaporator in frost-free systems, such as those found in domestic
fridge-freezers. It helps to eliminate unnecessary defrost cycles and also
increases the energy efficiency of the system.
Any frost-free system found in domestic and commercial fridge-freezers,
vending machines, ice-makers, etc.
2. Features
Simple detecting principle
Highly sensitive
Ease of assembly
Replaces less-efficient conventional sensors
4. Findings from studies carried on the FD Sensor
5. Specifications
6. Reliability
7. Mechanical properties
FROST DETECTING SENSOR
3. Dimensions
Study (B)
Study (A)
Study (C)
FD Sensor
1) Environmental Temperature range :
2) Operating temperature range
3) Sensitivity
Climatic test properties
A 12% of energy saving in a 420 liter domestic frost-free fridge-freezer was found by one of the major Japanese refrigerator manufacturers by the following test
procedures.
Test Procedure
The power consumption measurement was carried out in accordance with JIS C9607 power consumption test, item B (
The test procedure was extended to one week to determine the full advantage of the defrost system using the FD Sensor.
Evaluation of the FD Sensor in a 130 liter domestic frost-free fridge-freezer was made by another Japanese refrigerator manufacturer.
They obtained an energy saving of over 10% using the same test method as in 5(A) above but including the opening and closing the fridge-freezers
doors.
Evaluation of the FD Sensor in a 400 liter domestic frost-free fridge-freezer made by a Japanese refrigerator manufacturer shows an energy saving of over 10%.
Measurement of this energy saving was made using the test method specified as in 5(A) above.
(Difference in temperature measured by both NTC Thermistors when no frost is recognized.)
Conventional Fixedtime defrost system
Defeost system with FD Sensor
Improved efficiency
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Test
Dry heat
Test
Free Fall
Cold
Robustness of
termination
Damp heat
Thermal shock
Vibration
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Test Conditions
In air at 100 C for 1,000hr.
In air at
95% RH at 40 C for 1,000hr.
Between
Test Conditions
3 natural drops from 75 cm high
40 N for 10 seconds
JIS C2571 Item A
Housing
:
: 4 C 12 C
55 C for 1,000hr.
40 C and
40 C
40 C
1
5
18
80 C
5 C
75 C for 10,000 cycles.
65.6KK Whr/month
74.16KK Whr/month
Power Consumption
R4.3
5
Lead wire
12%
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Criteria
Deviation of resistance at 25 C from the original value
after test within
from the original value after test is within
Criteria
Deviation of resistance at 25 C from the original value
after test within
from the original value after test is within
No. of defrost cycle completed
Window
NTC Thermistor characteristics(only for reference)
1) Nominal Zero power resistance
2) Rated B value
3) Absolute difference between the two NTCs :
9 times/week
Once/week
Thermistor
2% and deviation of B value(B25 85)
2% and deviation of B value(B25 85)
Thermistor
Thermistor
Window
1%.
1%.
ISO8561).
Thermistor
Housing
: R25 10k
: B25 85 3435K
0.2% or
Evaporator Pipe
Lead wire
(mm)
0.05 C at 25 C
3%
1%
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