Honeywell G.m.b.h.

Lorne W Nelson

Thomas J Beckey

Ralph H Torborg

Eric W Grald

Michael R Levine

Dipak J Shah

Robert L Buchholz

Ulrich Bonne

James T Russo

J Ward MacArthur

David J Sutton

An environmental control system that utilizes the output of a thermostat to estimate the outdoor temperature can be used to eliminate the possibility of condensation on the inside of windows and on the inside of the walls. This is important in homes and buildings that are located in areas where the outdoor temperature gets very low. An acceptable humidity level can be calculated when the outdoor temperature has been determined. Once the acceptable humidity level is calculated, this value can be communicated to the humidistat so the humidity level within the house can then be adjusted accordingly. The humidistat can have the capability to manually override the automatic adjustments, thus giving the operator the flexibility of maintaining the humidity level within the building at a desired level.

Humidistat reset control

The present invention describes an apparatus and method for controlling the temperature in a plurality of comfort zones within a house or building. The invention contemplates a series of zone control devices which are selectively opened or closed to allow heating and/or cooling to individual zones. The temperature in each zone is sensed and compared to a preferred setpoint temperature to determine a temperature error for each zone. The respective temperature error signals for each zone are used to determine the zone of greatest thermal error. The zone of greatest thermal error is used to turn the heating/cooling plant on and off. The remaining zone or zones of lesser thermal error have their zone control devices closed or opened, depending upon the temperature error signal for their respective zones. In this manner, all zones are synchronized to the zone of greatest thermal error and to the cycle of the heating/cooling plant.

Error based zone controller

A zone control system uses signals from a plurality of separate zone thermostats to determine the zone of greatest thermal load or demand. Specifically, the on-time of each thermostat signal is integrated with respect to time so that the zone of greatest demand can be determined. The thermostat signal from the zone of greatest demand is used to control a duct damper between that zone and a heating/cooling plant. To synchronize the opening of the other zone duct dampers with the duct damper of the zone of greatest demand, the length of each of the on-periods of the thermostats in the other zones is first converted to the cycle rate of the zone of greatest demand thermostat since the other thermostats are operating at different duty cycles. A microprocessor-based master zone controller uses these converted on-signals to control respective zone duct dampers in the other zones coincident with the start of the thermostat on-period of the zone of greatest demand. Thus, the duty cycle of these duct control signals is equal to the duty cycles of the thermostats in the corresponding zones, but the control signals have time periods equal to that of the control signal for the zone of greatest demand.

Zone control system providing synchronization of system operation with

An electromechanical thermostat for controlling the on/off cycle of a heating/cooling unit. The thermostat has a temperature sensing element with a variable position according to the sensed temperature. Associated with the sensing element is a switch member that provides on/off signals in response to the position of the sensing element. The thermostat has mechanical heat anticipation to control the generation of the on/off signals. In the preferred embodiment the mechanical heat anticipation is accomplished by a stepper motor which varies the position of either the sensing element or switch member to simulate thermal heat anticipation. The thermostat also has a mechanical structure to reduce or eliminate thermostat droop. Preferably this structure includes a control circuit to detect the duty cycle of the heating/cooling unit and mechanically and automatically adjusts the thermostat set point.

Thermostat with mechanical heat anticipation and droop control

A method for improving cooling of a compressor element used in an air conditioning system and having a refrigerant compressor and associated drive motor hermetically sealed in a fluid-tight shell includes the steps of detecting an excessive increase in the temperature of the compressor element, intermittently operating the system during the excessive temperature detection with a superheat of a refrigerant in the system below zero superheat degrees to concurrently allow liquid refrigerant to enter the shell to enhance the cooling of the compressor apparatus by the latent heat of vaporization of the liquid refrigerant and terminating the intermittent operation and the admittance of the liquid refrigerant into the compressor element upon a detection of a desired temperature of operation of the compressor element. An air conditioning apparatus utilizing this method includes a device for introducing an intermittent perturbation into the control of an expansion valve located in a refrigerant flow line in the air conditioning apparatus. The control of this valve is based on a desired superheat of the refrigerant. The device may include either the introduction of a cyclic or sinusoidal variation in a superheat setpoint used for control of the expansion valve or the introduction of a cyclic variation in the gain of a superheat controller having an output signal controlling the expansion valve.

Method and apparatus for improving cooling of a compressor element in an

A refrigeration system comprises a compressor, a condenser, an evaporator, an accumulator, and an adjustable controllable expansion valve. An electronic control system monitors the value of superheat and accordingly provides an electrical control signal to adjust the controllable expansion valve in order to maintain a set point superheat value. An unfiltered path is provided to ensure expedient response when the system starts operation and when dynamic changes occur. A filtered path is provided to reduce hunting, or oscillations about the set point, of the superheat value during steady state operation.

Adaptive refrigerant control algorithm

The present invention is a technique for thermostatic control of a temperature modifying apparatus such as a heating unit or an air conditioning unit. This technique involves measuring the ambient temperature, generating an error signal based upon the difference between a set point temperature and the measured ambient temperature, operating the temperature modifying apparatus according to the error signal, and adjusting the set point temperature based upon the time history of the error signal. In accordance with the preferred embodiment of the present invention, the temperature modifying apparatus is operated during the next cycle interval with a duty cycle proportional to the error signal at the start of the cycle interval. In the preferred embodiment the set point is adjusted via an adjustment quantity which is increased if the new duty cycle factor is greater than the previous duty cycle factor, decreased if the new duty cycle factor is less than the previous duty cycle factor and maintained unchanged if the new duty cycle factor equals the previous duty cycle factor, with the adjustment quantity maintained within a predetermined band.

Thermostatic control without temperature droop using duty cycle control

The present invention is a technique for thermostatic control of a temperature modifying apparatus such as a heating unit or an air conditioning unit. This technique involves measuring the ambient temperature, generating an error signal based upon the difference between a set point temperature and the measured ambient temperature, operating the temperature modifying apparatus according to the error signal, and adjusting the set point temperature based upon the time history of the error signal. In accordance with the preferred embodiment of the present invention, the temperature modifying apparatus is operated during the next cycle interval with a duty cycle proportional to the error signal at the start of the cycle interval. In the preferred embodiment the set point is adjusted via an adjustment quantity which is increased if the difference between a desired temperature is of one sense decreased if the difference is of the opposite sense and maintained unchanged if the desired temperature equals the measured temperature, with the adjustment quantity maintained within a predetermined band.

A refrigeration system control method for minimizing off cycle losses in a heating mode of operation includes the steps of closing a valve in a refrigerant line between an indoor coil and an outdoor coil for a first predetermined period of time starting with a deenergization of a compressor and ending before a reenergization of the compressor to retain the refrigerant in the indoor coil and maintaining an energization of an indoor coil fan for a second predetermined time period after the deenergization of the compressor which second time ends before the first time period. An apparatus using this method includes an indoor condensor coil, an indoor coil fan, an outdoor evaporator coil, an outdoor coil fan, a refrigerant line connecting one end of the outdoor coil to one end of the indoor coil, a valve in the refrigerant line, a compressor means connecting the other end of the indoor coil to the other end of the outdoor coil and a timer for operating the valve, the indoor fan, the outdoor fan and the compressor in a predetermined sequence to produce a closed state of the valve for a first time period starting after a compressor operation and ending before a restoration of a compressor operation while maintaining an energization of the indoor fan for a second time period after a compressor operation and ending before the first time period to utilize the latent energy stored in the refrigerant and in the metal coil of the indoor coil.

Minimizing off cycle losses of a refrigeration system in a heating mode

A multizone control system utilizes a series of timers to ensure that all of the heat supplied to the system is utilized. Timers are used to control transfer of heat from the temperature modifying plant to the zones. The timers are further arranged to bring 'on' additional heat to the heat anticipator of the zone of lower demand thereby tending to synchronize the operation of zones and allow for more efficient supply of the heat exchange medium throughout the areas being controlled.

Zone control system for energy conservation

A control system for a refrigeration heat pump having an outdoor coil through which air is blown by a fan for extracting heat from outdoor air with means to defrost the coil periodically has a differential pressure responsive means responding to the differential air pressure across the outdoor coil. A time control means periodically operates the heat pump for a time controlled operation for predetermined time period (such as 90 minutes of elapsed operating time) and measures and stores the value of the differential pressure across the coil at the end of the time period in memory. A control means controls the heat pump between the periodically time controlled operations for normal operations for a total elapsed time operation in a pressure controlled operation until the pressure differential as previously stored occurs at which time a defrost cycle is initiated. Periodically a time controlled operation is initiated to update the pressure stored in the memory.

Defrost control system for a refrigeration heat pump apparatus

A two-stage thermostat means for an add-on heat pump installation provides separated control of a furnace and a heat pump. The two-stage thermostat means utilizes a single pole, single throw switch means, and a single pole, double throw switch means to properly stage and control a heat pump and a fossil fueled furnace so that they do not overlap. The control of the temperature of the heated area is independent of any need to connect a circuit between the thermostat in the heated area and any type of thermostat at the heat pump itself.

Thermostat for control of an add-on heat pump system

A furnace stack damper control apparatus has a motor for connection to a stack damper to open the damper upon a call for heat by a space thermostat. The motor is driven in a closed direction by electrical energization and in an open direction by a spring return. A relay having two normally open switches and a normally closed switch is energized when a space thermostat calls for heat. The normally closed switch then opens to allow the damper motor to open the damper by the spring return. The motor has an end switch having a normally open and a normally closed circuit. The normally open circuit is used with one of the normally open switches of the relay to energize a gas valve when the damper is open. The normally closed end switch is used to provide the energization circuit for the relay by the space thermostat and the relay is maintained energized when the damper is open by the other normally open switch of the relay connected in parallel to the normally closed end switch. The circuit provides for additional safety in that normal operation of the gas valve control apparatus does not take place if the normally open or normally closed end switches stick in either position.

Furnace stack damper control apparatus

An air conditioning system for providing an air cooling operation during a load phase management shutdown of the air conditioning compressor utilizes a thermally insulated cold water tank for storing chilled water. The water is cooled by a free cooling effect using wet bulb temperature drop of a refrigerant circulating between a secondary coil in a condenser section of the air conditioning system and a heat exchanger in the chilled water tank located below the condenser. The secondary coil in the condenser is cooled by a waterspray which can advantageously be derived from the condensate obtained from the evaporator section during a compressor operation phase of the air conditioning system. The chilled water is supplied to a chilled water coil in an evaporator section to cool the air flow in a chilled water cooling operation when the air conditioning compressor is inoperative during the load management phase of the peak hour of the air conditioning system.

Load management control air conditioning system

An induced draft combustion apparatus and its associated control system has a blower located in the exhaust stack or vent which is used to induce the movement of air and combustion products into, through and out of the combustion chamber. A flow-restricting orifice in the exhaust stack near the blower causes a region of higher pressure to exist upstream from the orifice with a region of lower pressure downstream from the orifice. An exhaust gas pressure signal representative of the exhaust gas volume flow rate is sensed on one side of the orifice and is fed back to a modulating gas valve which controls the outlet gas flow from the valve to be proportional to the magnitude of the exhaust gas volume flow rate. By controlling blower speeds and exhaust gas volume flow capacities as related to a selected orifice size, various firing rates for the furnace can be selected, from the design maximum down to various derated levels. Temperature-sensitive devices cooperating with the stack orifice or with the modulating gas valve are employed to compensate for changes in the density of the exhaust gas which accompany startup and changes in firing rate.

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Bloomington, MN, United States of America

Lorne W Nelson