General Electric Company

Donald L Sidebottom

Robert P Alley

Richard L Stottmann

Joseph R Noland

George E Stocking

Marvel A Elliott

John W Relyea

A microcomputer based monitor and display system for a refrigerator in which visual indicia are provided to indicate to the user the degree of door usage on a rolling average time basis. Threshold time limits are established to correspond to heavy, normal and light usage. The actual door-open time is sensed and accumulated in successive time segments. The rolling average door open time over a predetermined number of time segments is calculated at the end of each time segment and the appropriate lamp is lit depending on how the calculated average door-open time compares to the established threshold values.

Refrigerator door usage monitor and display system

Methods and circuits for providing auxiliary or remote temperature set or set-back capability in comparator-based thermostatic temperature control systems. In particular, the invention is applicable to thermostatic control systems of the general type including a temperature-responsive source for producing a temperature-dependent voltage as a function of sensed temperature, a reference voltage source for establishing a temperature set point, a voltage comparator having a comparison input and a reference input for producing a control output signal for energizing a thermal conditioning element when voltages applied respectively to the comparison and reference inputs have at least a predetermined relationship with respect to each other, an electrical connection between said temperature-responsive voltage source and the comparison input, and an electrical connection between the reference voltage source and the reference input. For remote temperature setting, the set point voltage applied to the comparator reference input is forced towards a particular value representative of a particular temperature by employing an auxiliary reference voltage source having an output impedance lower than that of the reference voltage source. Preferably, the auxiliary reference voltage source includes, as an output element, a unity-gain operational amplifier.

Air conditioning thermostatic control system having modular inclusion of

A user-operable power-up mode switch included within an electronic air conditioning mode control circuit of the type including momentarily-actuated user mode selection switches and a volatile mode selection memory. In the event of power interruption, the mode selection memory 'forgets' the last selected mode after a relatively short time when power supply filter capacitors have discharged. The power-up mode switch allows user selection of the particular mode in which operation resumes upon power restoration, but the user power up mode selections do not include all the operational modes selectable by the momentarily-actuated user mode selection switches. Thus operation continues in a mode at least appropriate for the season.

Air conditioning control system with user power up mode selection

A central desk air conditioning control system wherein each individual room unit is connected to a central desk location by a pair of control conductors. At the central desk location a SPST switch is connected across each pair of control conductors and effective, when closed, to place the connected individual room unit in a low energy mode. In the low energy mode, power relay drivers for major energy-consuming loads such as refrigerant compressors and electrical resistance heaters are disabled, while other loads, such as fans and control circuitry, remain energized. For the event that voltages are inadvertantly connected to the control conductors, a protective network is included in each individual room unit to prevent damage to its circuitry. The control circuitry for each individual room unit includes 'Freeze Sentinel' circuitry for energizing a heating load when required to ensure that room temperature does not fall below 40.degree. F. regardless of user control settings. In the low energy mode the Freeze Sentinel circuitry continues to operate manually.

Central desk air conditioning control system

In a self-contained air conditioner unit of the reversible refrigeration system type having cooling and heating cycles, a no-drain heat pump is provided wherein in the heating cycle, water collected on the outdoor heat exchanger operating as the system evaporator is transferred by a condensate disposal system to the indoor section. The condensate is atomized and directed into the indoor air flow and against the relatively warm indoor heat exchanger operating as the condenser to humidify the air. Control means are provided that prevent the condensate disposal system from directing condensate into the indoor air flow during the cooling cycle.

Air conditioning apparatus

A humidity sensor utilizing the electrical output of a piezoelectric crystal held in compressive stress at one end of a lever arm, the fulcrum at the other end of the lever arm consisting of a flexure hinge of moisture sensitive material with a thickness under 10 mils. The crystal is nested in a frame to which the flexure hinge is attached and the frame hinge and lever arm may be molded out of the same moisture sensitive material. A moisture sensitive form of Nylon may be used for the flexure hinge. The signal output of the crystal is a function of the compressive stress which in turn varies as the modulus of the flexure hinge varies as caused by changes in ambient humidity.

Humidity sensor

A demand defrost control system which bases the interval between future defrosting operations on the time (heater ON time) required for the defrost heater to raise the evaporator temperature to a predetermined temperature during a previous defrosting operation. There is an inverse relationship between heater ON time and defrost intervals. Additionally, an override is provided which measures the time the compressor and evaporator are energized during any single operation cycle. If this time exceeds a predetermined length of time, the interval before the next defrosting operation is shortened.

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Louisville, KY, United States of America

Donald L Sidebottom