Refrigeration control device to reduce power consumption of a refrigeration appliance

Abstract

A refrigeration control device to reduce power consumption of a refrigeration appliance has an ambient temperature/humidity sensor and a main controller. The ambient temperature/humidity sensor is mounted outside the refrigeration appliance. The main controller is mounted in the refrigeration appliance, is electronically connected to the ambient temperature/humidity sensor and at least one defogging heater in the refrigeration appliance and stores a dew point formula, a defogging database and a defogging control process. The defogging database is a table of multiple standard dew point values and multiple defogging duration values. The defogging control process calculates a dew point from the dew point formula, enters the table with the closest standard dew point value and extracts the corresponding defogging duration value from the table in the defogging database and activates the defogging heater for a number of times equal to the extracted defogging duration value.

1 . A refrigeration control device to reduce power consumption of a refrigeration appliance having at least one cabinet with each cabinet having a chill box and an external compartment, at least one expansion valve being mounted respectively in the chill box of the at least one cabinet, at least one evaporator being mounted respectively in the chill box of the at least one cabinet and being connected to the corresponding expansion valve, at least one optional defrosting heater being mounted respectively in the chill box of the at least one cabinet adjacent to the corresponding evaporator, a compressor being mounted in an external compartment of one of the at least one cabinet and being connected to the at least one evaporator, a condenser being mounted in an external compartment of one of the at least one cabinet and being connected to the compressor, at least one cooling fan being mounted respectively in the chill box of the at least one cabinet adjacent to the corresponding evaporator and blowing air in the corresponding chill box across the corresponding evaporator and at least one defogging heater mounted respectively in the chill box of the at least one cabinet, and the controlling device comprising:
 an ambient temperature/humidity sensor being mounted outside the chill box of the cabinet and sensing ambient temperature and humidity outside the chill box; and   a main controller being mounted in an external compartment of one of the at least one cabinet, being connected to the ambient temperature/humidity sensor and the at least one defogging heater and storing
 a dew point formula to calculate a dew point from ambient temperature and humidity outside the chill box; 
 a defogging database holding multiple standard dew point values and multiple defogging duration values corresponding respectively to the standard dew point values; and 
 a defogging control process being executed by the main controller to calculate a dew point, find a matching standard dew point value and extracting the corresponding defogging duration value in the defogging database and turning on the defogging heater for a number of times equal to the extracted defogging duration value. 
   
   
   
       2 . The refrigeration control device as claimed in  claim 1 , wherein
 the main controller further stores a default dew point calculating time interval; and   the defogging controlling process comprises steps of
 counting dew point calculating time interval; 
 determining if the dew point calculating time interval is equal to the default dew point calculating time interval; 
 sampling ambient temperature and humidity outside the cabinet and recounting the dew point calculating time interval when the dew point calculating time interval is equal to the default dew point calculating time interval; 
 calculating a dew point; 
 finding a matching standard dew point value corresponding to the calculated dew point; 
 extracting a defogging duration value corresponding to the matching standard dew point value; 
 turning on the defogging heaters; 
 counting defogging duration; 
 determining if the counted defogging duration is equal to the extracted defogging duration value; and 
 turning off the defogging heaters when the counted defogging duration is equal to the extracted defogging duration value. 
   
   
   
       3 . The refrigeration control device as claimed in  claim 1 , wherein
 the main controller further connects to the compressor, the at least one expansion valve, the at least one cooling fan and the at least one defrosting heater and further stores
 an expected defrosting time; 
 a defrosting setting time; 
 a predetermined delay time; and 
 a defrosting controlling process executed by the main controller to
 turn off the compressor and the at least one cooling fan, close the at least one expansion valve and turn on the at least one defrosting heater when the refrigeration appliance has operated for an interval equal to the expected defrosting interval; 
 turn off the at least one defrosting heater when the at least one defrosting heater has been turned on for a defrosting time equal to the defrosting setting time; and 
 turn on the compressor and the at least one cooling fan and open the at least one expansion valve after the at least one defrosting heater is turned off in a while. 
 
   
   
   
       4 . The refrigeration control device as claimed in  claim 3 , wherein the defrosting control process comprises steps of
 counting a working time when the refrigeration appliance is turned on;   determining if the working time is equal to the expected defrosting time;   turning off the compressor and the at least one cooling fan and closing the at least one expansion valve when the working time is equal to the expected defrosting time;   turning on the at least one defrosting heater;   counting defrosting time;   determining if the defrosting time is equal to the defrosting setting time;   turning off the at least one defrosting heater when the defrosting time is equal to the defrosting setting time;   counting a delay time;   determining if the delay time is equal to the predetermined delay time; and   turning on the compressor and the at least one cooling fan and opening the at least one expansion valve when the delay time is equal to the predetermined delay time.   
   
   
       5 . The refrigeration control device as claimed in  claim 3  further comprising at least one chill box temperature sensor being mounted respectively in the chill box of the at least one cabinet and sensing chill box temperature inside the chill box of the corresponding cabinet, wherein
 the main controller is further connected to the at least one chill box temperature sensor and stores at least one maximum temperature for the chill box of the at least one cabinet; and   the defrosting controlling process also turns off the at least one defrosting heater when the temperature inside the chill box of the at least one cabinet is equal to the corresponding maximum temperature.   
   
   
       6 . The refrigeration control device as claimed in  claim 5 , wherein the defrosting control process comprises steps of
 counting a working time when the refrigeration appliance is turned on;   determining if the working time is equal to the expected defrosting time;   turning off the compressor and the at least one cooling fan and closing the at least one expansion valve when the working time is equal to the expected defrosting time;   turning on the at least one defrosting heater;   counting defrosting time;   determining if either the temperature inside each chill box of the at least one cabinet is equal to the corresponding maximum temperature or the defrosting time is equal to the defrosting setting time;   turning off the at least one defrosting heater when either the temperature inside the chill box of the at least one cabinet is equal to the corresponding maximum temperature or the defrosting time is equal to the defrosting setting time;   counting a delay time;   determining if the delay time is equal to the predetermined delay time; and   turning on the compressor and the at least one cooling fan and opening the at least one expansion valve when the delay time is equal to the predetermined delay time.   
   
   
       7 . The controlling device as claimed in  claim 1  further comprising multiple chill box temperature sensors, wherein
 the refrigeration appliance has multiple cabinets, multiple expansion valves, multiple evaporators, multiple optional defrosting heaters, a compressor, a condenser, multiple cooling fans and multiple defogging heaters;   the chill box temperature sensors being mounted respectively in the chill boxes of the cabinets and sensing chill box temperatures inside the chill boxes of the cabinets; and   the main controller further connects to the expansion valves, the compressor and the cooling fans and further stores multiple maximum temperatures corresponding respectively to the cabinets, multiple minimum temperatures corresponding respectively to the cabinets and a compressor controlling process executed by the main controller to
 turn on the compressor and open all expansion valves when the temperature inside any chill box is higher than the corresponding maximum temperature; 
 close the corresponding expansion valve when the temperature inside any chill box is lower than the corresponding minimum temperature; and 
 turn off the compressor when all expansion valves are closed. 
   
   
   
       8 . The controlling device as claimed in  claim 7 , wherein the compressor control process comprises steps of
 monitoring temperatures inside the chill boxes;   determining if the temperature inside any chill box is higher than the corresponding maximum temperature;   determining if the compressor is on when the temperature inside any chill box is higher the corresponding maximum temperature;   turning on the compressor when the compressor is off;   opening all expansion valves when the compressor is on;   monitoring temperatures inside the chill boxes;   determining if the temperature in any chill box is lower than the corresponding minimum temperature;   closing the corresponding expansion valve when the temperature in any chill box is lower than the corresponding minimum temperature;   determining if all expansion valves are closed; and   turning off the compressor when all expansion valves are closed.