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Freezer Alarm &Backup Systems Preventing Sample Losses * * * * * * * * * * * * * * * * * * * * * * * *. Joe DeFrancesco, Gina Koskela, Peter Sturman Oregon State University North Willamette Research and Extension Center Aurora, Oregon. Freezer Alarm &Backup Systems.
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Freezer Alarm &Backup SystemsPreventing Sample Losses* * * * * * * * * * * * * * * * * * * * * * * * Joe DeFrancesco, Gina Koskela, Peter Sturman Oregon State University North Willamette Research and Extension Center Aurora, Oregon
Freezer Alarm &Backup Systems • Different modes of freezer and alarm failure • Freezer malfunction experiences at NWREC • Description of backup natural gas generator • Description of alarm system and phone dialer • Helpful hints to prevent loss of frozen samples
Modes of Freezer and Alarm Failure • Interruption of electrical power to facility • Area-wide power outage; local power outage (power pole on road) • Freezers, Alarm and Dialer system, need to have separate power source • Failure of individual freezers • Compressor failure (fan cover impediment; old age) • Freezer plug accidently pulled • Alarm failure due to circuit breaker failure • High ambient temperature → overload of circuit breaker to freezers • Have battery back-up on alarms and dialer just incase back-up generator fails after a main power outage • Alarm batteries = 6 hr usage; 24 hr stand-by • UPS (dialer) battery = 2 hr usage; 24-30 hr stand-by
Prior to Alarm and Backup System 100 amp Normal service panel Alarm Alarm TRT Freezer UTC Freezer
Freezer Alarm and Backup System 7 kw Natural Gas Generator 100 amp Normal service panel UPS (battery backup for dialer) 100 amp Automatic transfer switch Dialer Alarm (w/ battery backup) Alarm w/ battery backup TRT Freezer UTC Freezer
Interruption of Electrical Power to Facility • Interruption of electrical power is sensed by a Guardian 100 amp Automatic Transfer Switch (ATS) • ATS simultaneously disconnects normal power supply to freezers and alarms • Once ATS disconnects electrical power, it activates a 7 kw natural gas generator and connects power to the freezers and alarms • Generator is programmed to turn on once a week to test system
Freezer Alarm and Backup System 7 kw Natural Gas Generator 100 amp Normal service panel Dialer UPS (battery backup for dialer) 100 amp Automatic transfer switch Alarm (w/ battery backup) Alarm w/ battery backup TRT Freezer UTC Freezer
Power from Generator Power to Alarms and Horn Power to Freezers (2 separate circuits) Phone Dialer ATS UPS Battery Power to Phone Dialer Main Power Source Phone Line
Important: Separate circuits 1. UTC Freezer 2. TRT Freezer 3. Alarms, Horn, Dialer UTC Freezer Main Power TRT Freezer Alarms, Horn, and Dialer
Individual Freezer Failure • Each freezer is equipped with temperature sensing alarm • When alarm set point (25°F) is exceeded for one hour, alarm system is activated • Audible alarm (horn at freezer site) • Contact information posted on freezer doors • Automatic phone dialer calls each of the pre-programmed numbers on the emergency contact list with a recorded message • Programmed to delay for answering, then to repeat message 3x each number, then 3 reps • System tested at beginning of season when freezers are empty (about every other month) • Install individual circuit breakers to alarms; include battery backup
Freezer Alarm Schematic Automatic transfer switch UPS Auto phone dialer Freezer alarm Freezer alarm Alarm horn
Dial on each freezer indicates status of operation (connected to temp gauge in freezer); high temp may be due to defrost ~ Working (refrigeration) ~ Defrost
Helpful Hints to Prevent Sample Loss • Secure the freezer area • Locks on freezer doors • Indoors, with cool ambient air, is best to prevent failure • Frozen jugs of water to keep freezers cool • Backup temp recorders in freezers to verify sample integrity • Install alarm and backup systems; test regularly