Evaporator fan motor control in a refrigerated merchandiser

Abstract

A refrigeration apparatus having an evaporator fan motor control includes an evaporator to remove heat energy from the air in a cooled storage space. The evaporator transfers the heat energy to a refrigerant. At least one evaporator fan moves air from the cooled storage space across the evaporator to improve the transfer of heat energy into the refrigerant. The one or more evaporator fans have an energy consumption and generate a waste heat energy. A refrigeration control unit at least controls the operation of the one or more evaporator fans. During an off mode, the one or more evaporator fans are operated in a reduced energy consumption mode to reduce the energy consumption of the one or more evaporator fans and to reduce the waste heat while still defrosting the evaporator in the off mode.

1 . A refrigeration apparatus having an evaporator fan motor control comprising:
 an evaporator to remove heat energy from the air in a cooled storage space, the evaporator to transfer the heat energy to a refrigerant;   at least one evaporator fan to move air from the cooled storage space across the evaporator to improve the transfer of heat energy into the refrigerant, the one or more evaporator fans having an energy consumption and generating a waste heat energy; and   a refrigeration control unit to at least control the operation of the one or more evaporator fans; wherein during an off mode, the one or more evaporator fans are operated in a reduced energy consumption mode to reduce the energy consumption of the one or more evaporator fans and to reduce the waste heat while still defrosting the evaporator in the off mode.   
     
     
         2 . The refrigeration apparatus of  claim 1  wherein the reduced energy consumption mode comprises operating the evaporator fan at a reduced speed in the off mode as compared to the on mode. 
     
     
         3 . The refrigeration apparatus of  claim 2  wherein the evaporator fan is run at an increased speed in a pull down mode as compared to the on mode. 
     
     
         4 . The refrigeration apparatus of  claim 1  wherein the reduced energy consumption mode in the off mode comprises turning off at least one of a plurality of two or more evaporator fans that operate in the on mode. 
     
     
         5 . The refrigeration apparatus of  claim 4  wherein a pull down mode comprises turning on at least one more evaporator fan than the number of evaporator fans that run during the on mode. 
     
     
         6 . The refrigeration apparatus of  claim 1  wherein the reduced energy consumption mode comprises operating the evaporator fan in the off mode until an evaporator defrost condition is detected, and then turning off the evaporator fan until the next on cycle. 
     
     
         7 . The refrigeration apparatus of  claim 6  wherein a defrost condition is detected by sensing the temperature of the evaporator using a sensor selected from the group of sensors consisting of a bimetal switch, a bimetallic sensor, a thermistor, a thermocouple, a RTD, and an IR sensor. 
     
     
         8 . The refrigeration apparatus of  claim 1  wherein the refrigeration apparatus is a refrigerated merchandiser. 
     
     
         9 . The refrigeration apparatus of  claim 1  further comprising:
 a condenser to remove at least some of the heat deposited in the refrigerant and to transfer the removed heat to ambient air in the vicinity of the refrigeration apparatus;   at least one condenser fan to move ambient air across the condenser to improve the transfer of heat energy from the refrigerant to the ambient air; and   a compressor to increase the pressure of the refrigerant causing it to flow through the evaporator and the condenser.   
     
     
         10 . A method to reduce energy consumption in a refrigerator comprising the steps of:
 a. blowing air to be cooled from the refrigerated space of the refrigerator across an evaporator to transfer heat from a space to be cooled to a refrigerant with one or more evaporator fans during a refrigeration compressor on mode;   b. reducing the energy consumption of the one or more evaporator fans during a compressor off mode while still defrosting the evaporator during the compressor off mode.   
     
     
         11 . The method of  claim 10  wherein reducing the energy consumption of the one or more evaporator fans during a compressor off mode comprises reducing the speed of the one or more evaporator fans while still defrosting the evaporator during the compressor off mode. 
     
     
         12 . The method of  claim 10  wherein reducing the energy consumption of the one or more evaporator fans during a compressor off mode comprises turning off one or more of the evaporator fans while still defrosting the evaporator during the compressor off mode. 
     
     
         13 . The method of  claim 10  wherein reducing the energy consumption of the one or more evaporator fans during a compressor off mode comprises turning off the evaporator fans after an evaporator defrost condition had been detected during the compressor off mode. 
     
     
         14 . The method of  claim 13  wherein reducing the energy consumption of the one or more evaporator fans during a compressor off mode by turning off the evaporator fans after an evaporator defrost condition had been detected comprises reducing the energy consumption of the one or more evaporator fans during a compressor off mode by turning off the evaporator fans after an evaporator defrost condition had been detected by a temperature sensor during the compressor off mode. 
     
     
         15 . A refrigeration apparatus having an evaporator fan motor control comprising:
 an evaporator means for removing heat energy from the air in a cooled storage space, the evaporator means to transfer the heat energy to a refrigerant;   an evaporator fan means for moving air from the cooled storage space across the evaporator to improve the transfer of heat energy into the refrigerant, the evaporator fan means having an energy consumption and generating a waste heat energy; and   a refrigeration control means for controlling at least the operation of the evaporator fan means; wherein during an off mode, the evaporator fan means is operated in a reduced energy consumption mode reducing the energy consumption of the evaporator fan means and reducing the waste heat while still defrosting the evaporator in the off mode.   
     
     
         16 . The refrigeration apparatus of  claim 15  wherein the reduced energy consumption mode comprises the refrigeration control means operating the evaporator fan means at a reduced speed in the off mode as compared to the on mode. 
     
     
         17 . The refrigeration apparatus of  claim 15  wherein the reduced energy consumption mode in the off mode comprises the refrigeration control means turning off at least one fan of the evaporator fan means that operate in the on mode. 
     
     
         18 . The refrigeration apparatus of  claim 15  wherein the reduced energy consumption mode comprises the refrigeration control means operating the evaporator fan means in the off mode until an evaporator defrost condition is detected by a defrost detection means, and then turning off the evaporator fan until the next on cycle. 
     
     
         19 . The refrigeration apparatus of  claim 15  further comprising:
 a condenser means for removing at least some of the heat deposited in the refrigerant and to transfer the removed heat to ambient air in the vicinity of the refrigeration apparatus;   a condenser fan means for moving move ambient air across the condenser to improve the transfer of heat energy from the refrigerant to the ambient air; and   a compressor means for increasing the pressure of the refrigerant causing it to flow through the evaporator and the condenser.