Abstract: A controller includes a first input that receives a signal indicating an energy consumption value of a compressor, a second input that receives a signal indicating an energy consumption value of a variable speed condenser fan, a third input that receives a signal indicating an ambient temperature, a fourth input that receives a signal indicating a condenser temperature, an output that provides a control signal to the variable speed condenser fan, a memory that stores a temperature difference set-point, and a processor in communication with the inputs, the output and the memory. The processor calculates a difference between the ambient temperature and the condenser temperature, compares the difference with the temperature difference set-point, controls the variable speed condenser fan based on the comparison, monitors the energy consumption values, and modulates the temperature difference set-point to minimize energy consumption.

Abstract: A method for monitoring refrigerant in a refrigeration system includes sensing, a refrigerant pressure of a refrigeration system, averaging the refrigerant pressure over a time period, determining an expected pressure based on said time period, comparing the average to the expected pressure, and determining a system condition based on said comparison. The method may be executed by a controller or stored in a computer-readable medium.

Abstract: A controller comprises a first input that receives a signal indicating an energy consumption value of a compressor, a second input that receives a signal indicating an energy consumption value of a variable speed condenser fan, and an output that provides a control signal to the variable speed condenser fan. The controller also comprises a memory that stores a condenser set point, and a processor in communication with the input, output and memory and that modulates the condenser set-point to minimize energy consumption and controls the variable speed condenser fan based on the condenser set-point.

Abstract: A controller comprises a first input that receives a signal indicating an energy consumption value of a compressor, a second input that receives a signal indicating an energy consumption value of a condenser fan, and an output that provides a control signal to the condenser fan. The controller also comprises a memory that stores a condenser set point, and a processor in communication with the input, output and memory and that modulates the condenser set-point to minimize energy consumption and controls the condenser fan based on the condenser set-point.