US 12,460,849 B2
Defrost systems and methods for heat pump water heaters
Alex Williams, Montgomery, AL (US); and Piyush Porwal, Montgomery, AL (US)
Assigned to Rheem Manufacturing Company, Atlanta, GA (US)
Filed by Rheem Manufacturing Company, Atlanta, GA (US)
Filed on Oct. 24, 2023, as Appl. No. 18/493,225.
Application 18/493,225 is a continuation of application No. 17/218,390, filed on Mar. 31, 2021, granted, now 11,835,277.
Prior Publication US 2024/0053072 A1, Feb. 15, 2024
Int. Cl. F25B 47/02 (2006.01); F24D 17/02 (2006.01); F25B 49/02 (2006.01)
CPC F25B 47/02 (2013.01) [F24D 17/02 (2013.01); F25B 49/022 (2013.01); F25B 2347/02 (2013.01); F25B 2600/02 (2013.01); F25B 2700/02 (2013.01); F25B 2700/11 (2013.01); F25B 2700/2104 (2013.01); F25B 2700/21174 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A heat pump water heater system, comprising:
a refrigerant circuit;
an evaporator coil in fluid communication with the refrigerant circuit;
a fan configured to move air in a first direction through an inlet then across the evaporator coil and then trough an outlet when the heat pump water heater system is heating water and move air in a second direction through the outlet then across the evaporator coil and then through the inlet when operating in a defrost mode;
one or more temperature sensors;
a heating element located proximate an air flow path between the fan and the evaporator coil; and
a controller configured to:
receive temperature data from the one or more temperature sensors; and
in response to the temperature data, output defrost instructions for:
the heating element to activate;
the heat pump water heater system to stop heating the water; and
the fan to change from a configuration to move air in the first direction to a configuration to move air in the second direction across the heating element then the evaporator coil to defrost the evaporator coil using the air blown by the fan and then through the inlet, wherein the heating element is configured to heat the air blown by the fan.