Honeywell G.m.b.h.

Robert T Ruminsky

Stephen L Serber

Dale A Mueller

B Hubert Pinckaers

Rodger C Wolfgram

An outdoor coil defrost control system for a reverse cycle refrigeration system comprising outdoor air temperature sensing means, means for producing an output signal indicative of the operation of the refrigeration compression means, and a special controller means having operative connections to the temperature sensing means and compression sensing means and comprising in part (a) a special variable frequency oscillator having an input indicative of the outdoor air temperature and an output signal the frequency of which varies as a non-linear function of the magnitude of the outdoor air temperature, (b) a counter means having an input connected to receive the output signal of the variable frequency oscillator, and (c) means for placing said refrigeration system into an outdoor coil defrost mode of operation upon the counter means counting a preselected number of counts or pulses.

Heat pump system defrost control

A temperature control system for a building has a temperature responsive means or thermostat in the space for controlling a temperature conditioning apparatus furnishing temperature condition medium to the space. A time control apparatus provides for a reduction or deviation of the space temperature during certain time periods for the purpose of energy conservation and/or comfort. The space temperature is restored to the normal temperature by a pickup operation. The magnitude of temperature setback initially selected or to be maintained during the setback time period is automatically adjusted by responding to the actual building heat load, so as to keep the time and heating capacity needed to restore the space to the normal temperature within certain limits.

Temperature control system with night setback programming as a function

A control system for a refrigeration system for controlling the defrosting of one of the heat exchange coils thereof; the control system comprising a nozzle element positioned adjacent to one side of the evaporator coil at a point where frost may build up on the evaporator coil; compressed air means connected to the nozzle through valve means and controllable to selectively permit air to be discharged from a nozzle against the coil; air flow sensor means positioned on the other side of the evaporator coil in register with a nozzle, the sensor means including switch means adapted to be actuated upon said sensor being impacted by a stream of air; and controller means adapted to periodically actuate the valve means so as to cause periodic pulses of air to flow from the nozzle through the evaporator coil, said controller further functioning to place the system into a defrost mode of operation upon said sensor switch means being unactuated for a period of time exceeding the cycle period of the actuation of the valve means.

Defrost control system for refrigeration system

An evaporator coil defrost control system for a refrigeration system comprising refrigerant compression means, a condenser coil, an evaporator coil, and an electric motor operated fan positioned adjacent to said evaporator coil and adapted, when energized, to blow air through said evaporator coil, said defrost control system comprising: strain sensing means connected to said fan blades and adapted to measure force applied to said fan and to produce a signal indicative of said measured force; controller means connected to said strain sensing means to receive the signal therefrom and having operative connections to said system, said controller being adapted to place said system in a defrost mode of operation upon said signal of said strain sensing means having a characteristic indicative of a significant frost build-up on said evaporator coil.

A minimum off-time protection arrangement is disclosed for compressors, particularly refrigeration type compressors. A current transformer is placed in the circuit which controls the switching of the compressor and that current transformer provides a control signal to a minimum off-time circuit. The minimum off-time circuit prevents the compressor from being restarted for some minimum period of time after once being operated.

Compressor minimum off-time system

A condition responsive element, disclosed as a negative temperature coefficient thermistor, operates in conjunction with a bridge circuit to provide a differential input to a special direct current amplifier system. The amplifier system utilizes a combination of positive feedback and negative feedback with the negative feedback always exceeding the level of the positive feedback under steady state operating conditions. The output of the amplifier means further is connected to the lowest energizing potential for the amplifier means through a network that includes a relatively fixed voltage dropping means so that changes in the negative feedback can be made to change the gain of the amplifier system with a minimum of offset or change in calibration of the condition responsive device.

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Bloomington, MN, United States of America

Robert T Ruminsky