Carrier Corporation

Lynn A Turner

Rajendra K Shah

Eugene L Mills, Jr

Eugene L Mills

Don Alan Schuster

A heat pump is provided having a first heat exchanger and a second heat exchanger. A compressor is fluidly coupled to the first heat exchanger and the second heat exchanger. A reversing valve is fluidly coupled between the first heat exchanger and the second heat exchanger. The reversing valve is adapted to flow of a refrigerant from the compressor to the first heat exchanger during heating mode and to the second heat exchanger during a cooling mode. A thermal expansion valve is positioned between the first heat exchanger and the second heat exchanger. An electronic expansion valve is positioned between the first heat exchanger and the second heat exchanger. A controller is electrically coupled to operate the electronic expansion valve between a fully open, a fully closed and a modulated position depending on the operation of the compressor.

Heat pump and method of operation

An air conditioning system that comprises a controller that is in electrical communication with a compressor, a condenser fan, a temperature sensor that measures the temperature of the ambient air, a temperature sensor that measures the temperature of a condenser coil of the air conditioning system, and a low pressure switch (LPS) that measure the pressure of a refrigerant disposed within the air conditioning system. An algorithm resident on the controller controls the controller to enter a low ambient cooling mode when the temperature of the ambient air is less than a set temperature. The algorithm further controls the controller so that a minimum and/or maximum cycling frequency is imposed on the condenser fan. The algorithm further controls the controller so that the controller does not respond to an LPS trip during the early part of a cooling cycle under low outdoor temperature conditions, which might not accurately indicate a system fault, but still shuts down the compressor in response to an LPS trip under conditions that truly indicate a system fault.

Air conditioning system for low ambient cooling

A motor starting apparatus () includes a motor starting relay () to switch a motor starting capacitor () into a motor circuit across a run capacitor (). The system control () includes an electronic voltage measurement circuit to measure a winding voltage () of the motor winding (). The system control () also includes a microprocessor to run an algorithm that causes the system control to switch the starting capacitor () out of the motor circuit when a measured winding voltage () exceeds a winding voltage threshold. A method to start a motor includes the steps of determining a motor winding voltage () threshold; closing the motor starting capacitor relay () when needed; closing a contactor () to supply power to the motor starting apparatus and the motor circuit; measuring a winding voltage (); comparing the measured winding voltage () to the voltage threshold; and opening the starting capacitor relay () when measured winding voltage () exceeds the voltage threshold indicating that the motor has been started.

Electronic method for starting a compressor

A heat pump having an indoor coil that operates as a condenser when the system is in a heating mode and an outdoor coil that operates as an evaporator when the system is in the heating mode. A variable speed indoor fan is used to move supply air over the indoor coil and a temperature sensor is arranged to provide ambient outdoor temperature data to a programmable computer. The computer contains a schedule for continuously adjusting the speed of the indoor fan in response to changes in the ambient temperature so as to maintain the temperature of the supply air at a constant level. In doing so, the compressor discharge pressure is also maintained within allowable limits and is held substantially constant.

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Avon, IN, United States of America

Lynn A Turner