Freezer room has two main parts : indoor units and outdoor units. Indoor units are consisted of evaporator and its control like expansion valve, heater, ntc bulb sensor to monitor its cooling temperature insode room. And outdoor units are consisted of compressor machine, condenser ( oil separator, heat exchanger for big system), and its control like electric panel with digital controller, ntc bulb for temperature control of outside air, filter, sight glass, solenoid valve, danfoss pressure controller, oil pressure sensor.
Freezer room machine can be set its cooling temperature desired. Pressure controller can be used to detect differential pressure of high pressure and low pressure at the compressor. If non stop operation is desired, timer set on and pressure control such a kp danfoss to limit defrost time during half hour and starting again while evaporator fans still operate.
Problem : y=f(x)
Dy/dx= P per t
Di/dt = I^2.per t
y=I^2 e ^-t/L/r
Start : Pinductive = I^2 max.0.36
P=Limit t=0.36 integral I^2 t dx,
P varies if time constant changes
P >P out
P=P if time constant 1
P < P out x 1.25
Heater works to increase refrigerant pressure mixed to compressor. So, that refrigerant makes good start-up.
Continuous operation may cause lack of refrigerant. Kp pressure does not work when applying little liquid of refrigerant. At high ambient temperature with heater and fan continuously running: P <P out inductive. The Impact is heater burnt out because magnetic field is high when all units are operating without setting up the defrost time.
Comparing to the system with electric device protection used defrost time,
30 to 45 minutes defrost time with only evaporator fan and heater work. It always P > Pout. Sensor kp danfos will detect pressure, so the ntc bulb detects temperature while heater energizes heat during physical conversion of refrigerant.
Freezer room machine can be set its cooling temperature desired. Pressure controller can be used to detect differential pressure of high pressure and low pressure at the compressor. If non stop operation is desired, timer set on and pressure control such a kp danfoss to limit defrost time during half hour and starting again while evaporator fans still operate.
Problem : y=f(x)
Dy/dx= P per t
Di/dt = I^2.per t
y=I^2 e ^-t/L/r
Start : Pinductive = I^2 max.0.36
P=Limit t=0.36 integral I^2 t dx,
P varies if time constant changes
P >P out
P=P if time constant 1
P < P out x 1.25
Heater works to increase refrigerant pressure mixed to compressor. So, that refrigerant makes good start-up.
Continuous operation may cause lack of refrigerant. Kp pressure does not work when applying little liquid of refrigerant. At high ambient temperature with heater and fan continuously running: P <P out inductive. The Impact is heater burnt out because magnetic field is high when all units are operating without setting up the defrost time.
Comparing to the system with electric device protection used defrost time,
30 to 45 minutes defrost time with only evaporator fan and heater work. It always P > Pout. Sensor kp danfos will detect pressure, so the ntc bulb detects temperature while heater energizes heat during physical conversion of refrigerant.
No comments:
Post a Comment