Frozen evaporator coil detection and defrost initiation
AssigneeCarrier Corporation
InventorLucy Yi Liu
Life of this patent
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Abstract
A method is disclosed or detecting a frozen evaporator coil of a refrigerant vapor compression system for supplying conditioned air to a temperature controlled space before ice build-up on the evaporator coil becomes so excessive as to result in an undesirable on-off cycling of the refrigerant vapor compression system compressor when operating to a frozen temperature maintenance mode. The method may also include initiating a defrost of a frozen evaporator coil of the refrigerant vapor compression system before ice build-up on the evaporator coil becomes so excessive as to result in an on-off cycling of the refrigerant vapor compression system compressor when operating to a frozen temperature maintenance mode.
Claims9
A method for preventing a frosted evaporator heat exchanger coil of a refrigerant vapor compression system for supplying conditioned air to a temperature controlled space, the method comprising:
- determining whether a change in an air flow temperature differential across the evaporator heat exchanger coil over a preselected period of time at least equals a set point threshold change in air flow temperature differential;
- determining whether a change in a refrigerant pressure condition on a low pressure side of the refrigerant vapor compression system over said preselected period of time at least equals a set point threshold change in refrigerant pressure condition;
- if both the change in an air flow temperature differential across the evaporator heat exchanger coil over a preselected period of time at least equals a set point threshold change in air flow temperature differential and the change in a refrigerant pressure condition on a low pressure side of the refrigerant vapor compression system over said preselected period of time at least equals a set point threshold change in refrigerant pressure condition,
- determining whether a current magnitude of the air flow temperature differential across the evaporator heat exchanger coil at least equals a set point threshold magnitude for the air flow temperature differential, and determining whether a current magnitude of the evaporator heat exchanger coil refrigerant pressure condition at least equals a set point threshold magnitude for the refrigerant pressure condition;
- and
- initiating a defrost of the evaporator heat exchanger coil if both the current magnitude of the air flow temperature differential across the evaporator heat exchanger coil at least equals a set point threshold magnitude for the air flow temperature differential, and the current magnitude of the evaporator heat exchanger coil refrigerant pressure condition at least equals a set point threshold magnitude for the refrigerant pressure condition.
Dependencies are inferred from the claim text.