Abstract: A humidification system for use with a heating unit to modify and maintain a predetermined level of humidity in an enclosed space using a pulse circuit for energizing a solenoid valve to allow pulsed output of water from a misting nozzle, The system operating the pulse circuit in a plurality of modes to provide humidity to the enclosed space,

Abstract: An electric expansion valve is arranged between a first indoor heat exchanger and a second indoor heat exchanger. At a time of cooling operation, the electric expansion valve is fully opened to connect both the indoor heat exchangers to each other. At a time of dehumidifying operation the electric expansion valve is narrowed to apply a pressure reducing action across these indoor heat exchangers so that the first indoor heat exchanger acts as a reheater and the second indoor heat exchanger as an evaporator. The indoor air is cooled and dehumidified by the second heat exchanger and then reheated by the first indoor heat exchanger and blown into the room. At a time of dehumidifying operation, the temperature of the air blown into the room varies by controlling the speed of an outdoor fan.

Abstract: An interior atmosphere control system contains a group of sensors to detect/measure indoor and outdoor air temperature, humidity, air pressure, oxygen content, carbon-dioxide content, static electric charge, indoor wall temperature, sound and light. These measured results, through a signal transfer interface, are sent to a microcomputer which also accepts a user's command as input data through a user's interface.

Abstract: A temperature and humidity controlled fan for ventilating a building foundation including a housing mounted in the foundation wall. The housing includes the fan and a temperature responsive ganged louver arrangement for opening and closing the housing for ventilation usage.

Abstract: A ventilation apparatus for a container for transporting goods by truck or ship. The walls of the container are provided with an inlet opening and an outlet opening, and an inlet unit is connected to the inlet opening and an outlet unit is connected to the outlet opening. The outlet unit is provided with a battery-operated fan for a forced ventilation of the container, temperature sensors are provided for detecting the inner wall temperature and inner air temperature, and a degree of change in the wall temperature per unit of time is calculated for operating the fan when the degree of change in the wall temperature is larger than a predetermined value. Furthermore, the difference between the inner air temperature and the wall temperature is calculated, and the fan is operated when that difference is larger than a predetermined value.

Abstract: An electronic expansion valve is provided between first and second indoor heat exchangers. At the time of cooling operation, the electronic expansion valve is fully opened with the result that the first and second indoor heat exchangers are communicated with each other. At the time of dehumidifying operation, the opening of the electronic expansion valve is decreased to apply the effect of pressure reduction between the indoor heat exchangers, so that the first indoor heat exchanger functions as a reheater and the second indoor heat exchanger functions as an evaporator. The air in the room is cooled and dehumidified by the second indoor heat exchanger and then discharged into the room after being reheated by the first indoor heat exchanger. At the time of the dehumidifying operation, controlling the speed of the outdoor fan permits the temperature of the air discharged into the room to be varied.

Abstract: An affordable ventilation controller comprises a low cost and very stable carbon dioxide sensor and a remote-controlled louvered suction fan equipped with an air filter. The ventilation controller operates independently of any existing heating or cooling system that might be present in a closed room. The carbon dioxide sensor measures accurately the gas concentration level in parts-per-million (ppm's) as a ventilation index. When a predetermined ventilation index is exceeded indicative of bad ventilation, a remote-controlled suction fan equipped with a louver and an air filter is activated to draw in fresh air from the outside in order to regulate the CO.sub.2 concentration and provide good ventilation. However, if an exceedingly high concentration of CO.sub.2 is sensed, the controller inhibits the control signal to the suction fan, since such a high level might indicate the presence of a fire.

Abstract: Humidity control system for regulating the relative humidity of air which is forced through a spray painting booth. The humidity control system employs a water spray nozzle which atomizes water to quickly change the relative humidity and temperature of the ventilation air moving through the paint spray booth. A flow control valve which opens at a predetermined rate to control the water flow to the water spray nozzle in a manner which provides for an overdamped response to changes in the relative humidity level. The humidity control system further includes a motor for operating the flow valve, a controller for energizing the motor, and suitable sensors for providing feedback to the controller. The low predetermined rate at which the flow valve opens allows the water flow through the flow valve to be modulated by the length of time which the motor is energizes.

Abstract: An air ventilating system for use to ventilate and dehydrate and dehumidify the insulation immediately under the roof structure. The system includes an air intake member, to draw in relatively dry air, generally located above the roof surface, and a central distribution member, in the form of a plenum, disposed above or below the roof structure, and a plurality of radiating pipes that lead from the distribution plenum member, and which are located above, below or at the same level as the insulation layer under the roof structure, with such distribution pipes having a plurality of small openings therein to disperse air to the surrounding insulation layers for purposes of aerating same to remove moisture from the insulation.

Abstract: A system for providing adaptable control of an HVAC system which regulates environmental conditions within an enclosed area. In a preferred embodiment, the apparatus and method of the present invention measures selected environmental variables in the enclosed area, calculates a value of a comfort index which is a function of the values of the selected environmental variables and a plurality of parameters that predicts a thermal sensation rating of an occupant. The system receives an actual thermal sensation rating from the occupant and compares the predicted thermal sensation rating with the actual thermal sensation rating to determine a difference between the predicted thermal sensation rating and the actual thermal sensation rating.

Abstract: A cooling system comprising an airtight box which accommodates a cooling module and an electronic device which is cooled by the cooling module and has a door which is opened when attending to maintenance of parts within the airtight box, a dew condensation preventing unit for absorbing humidity within the airtight box and/or replacing air or gas within said airtight box when operated, a coolant supply unit for recirculating a coolant between the coolant supply unit and the cooling module, and a controller for operating the coolant supply unit and the dew condensation preventing unit in response to a first instruction signal which instructs a cooling operation, and for heating the electronic device in response to a second instruction signal which instructs the maintenance of the parts within the airtight box, where only one of the first and second instruction signals exists at one time.

Abstract: A power actuated roof vent apparatus generally comprises an insulated air passageway housing through the roof which allows a linear and unrestricted air flow through the air passageway housing when the apparatus is in operation and an insulated passageway closure lid which positively closes the air flow through, and prohibits water ingress into, the air passageway housing when the apparatus is not in operation.

Abstract: There is described an analyzer for determining analytes of a body liquid, in which stacks of test elements are stored prior to use. To control the level of humidity in which the stacks are stored, first and second compartments are provided with access openings connecting them to the stack-storage area. A mechanism is provided for selectively closing off and opening up the access openings, and for actively forcing air to flow from either of the compartments into the storage area. One of the compartments has a supply of water, and the other has a desiccant.

Abstract: An environmental control system providing a healthful environment in an enclosed structure for people living, working, travelling, or spending leisure time in the structure. The environmental control system may include a heating, ventilating and air conditioning unit, for controlling the temperature and humidity of air within the structure and pressurizing the interior of the structure, and an air cleaning system. The air cleaning system preferably includes a pre-filter unit to remove larger particulates, a medium efficient extended surface type filter device for capturing smaller particulates, a chemical and/or activated carbon filter device to provide gas phase air purification and scrubbing, and a high efficient particulate air filter device. If desired, an electronic air filter device can be included. An air quality measuring unit monitors the cleanliness of the air passing from the system.

Abstract: A window fan with an electronic controller having an AUTO mode of operation that is responsive to the .DELTA.T between inside and outside temperature, a minimum inside temperature threshold, and the outside relative humidity. Accordingly, if it is relatively hot or humid outside, or if it is relatively cold inside, the window fan is inactive. Thus, the fan is automatically activated only during those time periods when it is most advantageous to ventilate with outside fresh air.

Abstract: A thermostat is disclosed which includes a Proportional-Integral-Derivative (PID) controller and a means for disabling the PID controller for selected periods. The PID controller is disabled during a temperature recovery period, which can be triggered by the occurrence of one or more of many preselected events. The PID controller is re-enabled when the thermostat setpoint less a void offset temperature is reached. To reduce error in future temperature recovery periods, the void offset temperature is adjusted after a temperature recovery by adding the amount of error to the void offset temperature to create a new void offset temperature for use in a next temperature recovery period.

Abstract: A system for HVAC and humidification includes a control signal source which supplies two distinct control signals over two wires of a four wire link. The control signals are supplied to a temperature control signal source and for a fan/humidity control signal source. The temperature control signal source generates a temperature control signal and transmits the temperature control signal to a temperature signal decoder by means of a third wire of the four wire link. The temperature signal decoder decodes the temperature control signal and turns on either a furnace or an air-conditioner. The furnace and the air-conditioner each have a connection to a fan so that the furnace and the air-conditioner can each signal the fan to blow the heated or cooled air into the living area. The fan/humidity control source operates independently of the temperature control signal source and generates a fan/humidity control signal for transmission over a fourth wire of the four wire link.

Abstract: A non-circulating water system for use in evaporative coolers which incorporates a timing means in conjunction with a valve means, to control the flow of water to the pads. It applies measured amounts of water to the pad and allows measured amounts of time between applications so that most of the water is used in the evaporation process and minimal amounts of water are discharged though a drain. Domestic water line pressure is used to transfer water to the pads, eliminating the need for reservoir water, float valve, pump and overflow pipe. The cycle of the timing means may be varied dependent on moisture or temperature conditions sensed in the pad.

Abstract: Method and apparatus for treating fruits including use of an air plenum above palletized boxes of fruit to force air through the plenum and to the front of the trailer containing the palletized fruit. The air in very high volume per minute is forced downwardly and drawn through the fruit to provide controlled temperature and humidity. A portion of the exhaust air is recirculated while maintaining high humidity of at least 75% and temperature difference between inlet and exhaust air of no greater than 5.degree. F.

Abstract: Improved means for automatically controlling an evaporative cooler having a pump and blower, said control system comprising a solid state electronic temperature sensing circuit capable of sensing temperature differences of considerably less than 0.1 degree Fahrenheit, a timer for activating the cooler pump a predetermined period prior to and following activation of the blower, logic means for controlling activation and cycling of said blower, and humidity sensing means for developing an electrical signal indicative of excessive atmospheric humidity for turning off said cooler and controlling an associated air conditioner.

Abstract: This invention relates to an electric drying apparatus automatic controller which automatically controls an electric drying apparatus in order to dry the articles put therein within a shortest period of time and with minimized power consumption. The control includes a timer, a humidity controller, and an exhaust control valve, wherein the timer is connected between the switch and the heater of an electric drying apparatus with the humidity controller and the exhaust control valve connected thereto. This controller is characterized in that the timer is preset for a certain period of heating time, to turn on the heater for heating, and starts counting time when the drying apparatus is turned on. While the timer is counting, the humidity controller can stop the timer's counting or reset the timer according to the relative humidity detected within the drying apparatus.Also, the humidity controller opens or closes the exhaust control valve based upon the humidity within the frying apparatus.

Abstract: The present application relates to a means and method for simultaneously and independently controlling a pressure of a medium including refrigerant pressure of one and a plurality of output devices and for controlling a current input to one and a plurality of output devices in a relationship in accordance with a point temperature setting, a point humidity setting, and a point air velocity setting; enabling the circuit connecting one and a plurality of output devices to be broken upon a predetermined current deviation beyond the current controlled in a relationship to the point temperature, humidity, and air velocity of their respective settings; enabling the automatic resetting of the circuit to the power supply when the predetermined current deviation had been alleviated; enabling one or more output devices including a compressor of a refrigeration circuit to be maintained running after the temperature of a space becomes equal to the point temperature of a temperature setting and after the humidity of a spac

Abstract: An acutioneering control adapted to be connected to a thermostat control for temperature modifying apparatus wherein the thermostat control includes a temperature sensor which provides a sensed temperature signal. The auctioneering control includes apparatus for sensing absolute humidity and providing a first output signal corresponding to the sensed absolute humidity; first apparatus for comparing the sensed absolute humidity with a predetermined value wherein the first comparing apparatus receives the first output signal and provides a humidity error signal; apparatus for modifying a predetermined temperature setpoint signal responsive to the humidity error signal; apparatus for limiting the modified temperature and providing a limited temperature setpoint signal; and second apparatus for comparing the limited temperature setpoint signal with the sensed temperature signal.

Abstract: An automatically controlled, responsively to minimum temperature and humidity levels, ventilation system for crawl spaces beneath a house or other structure includes at least one intake unit and one exhaust unit. The intake unit includes at least one solenoid-operated ventilator and a temperature sensing device positioned to sense the temperature of outside air. The exhaust unit includes at least one solenoid-operated ventilator, a fan, and a remote humidistat positioned to sense the humidity level at a prescribed area of the crawl space. When the humidity rises above a prescribed level, the humidistat closes an electrical circuit to the thermostat. If the outside air temperature is above a prescribed level (at least above freezing), the thermostat closes the second circuit, energizing the solenoids and the fan. The solenoids cause the ventilators to open and the fan forces air through the crawl space to reduce moisture levels and dissipate any build-up of Radon gases beneath the structure.

Abstract: A heat-pump type refrigeration cycle includes at least a compressor capable of switching between cooling and heating modes. A first memory stores first reference temperature data for the cooling mode, and second reference temperature data for the heating mode. A second memory stores first set data for setting a cooling temperature and second set data for setting a heating temperature. A mode selector compares room temperature detection data with the first and second reference temperature data, in accordance with an automatic operation instruction, and outputs a first signal for selecting the cooling mode or a second signal for selecting the heating mode. A controller sets the heat-pump type refrigeration cycle in the cooling or heating mode, in accordance with the first or second signal, and controls the compressor in a drive state or a stop state, so that a comparison difference between the first or second set data and the room temperature detection data becomes zero.

Abstract: A system for controlling environmental conditions including irrigation or misting in greenhouses having a plurality of crop beds within one greenhouse enclosure arranged into a plurality of sense zones and a plurality of control zones comprises a plurality of sensors stationed over crop beds within each sense zone comprising an aspirated enclosure and means therein for generating analog electrical signals indicative of web bulb and dry bulb temperatures and also means for generating an analog electrical signal indicative of incident light over the bed of a microcomputer.

Abstract: A system for controlling environmental conditions including irrigation or misting in greenhouses having a plurality of crop beds within one greenhouse enclosure. Aspirated enclosures have associated temperature sensors for measuring dry bulb temperature and humidity, the temperature of a surface over the bed and also a sensor of incident light over the bed. A computer is programmed with a task for inputting temperature data and for calculating the vapor pressure deficit over each bed and for inputting incident light data for measuring a parameter indicative of physiological crop age. A task establishes times for supply of water based upon the gathered data.

Abstract: A temperature and humidity control system for natatoriums. The system provides a constant volume of air circulation which is used to control temperature and humidity in the natatorium while inhibiting the accumulation of moisture on the surfaces defining the natatorium. Usually, ambient air is introduced into the system and moisture latent air discharged from the system under controlled conditions. When the humidity of the ambient air is too great the system operates in a self-contained cycle. Return air from the natatorium flowing through the system is treated to maximize its relative humidity. Subsequently, it flows across a cooling coil. This cooled air flows through a heat exchange module where it is placed in exchange relationship with the air being drawn from the natatorium. It cools the air drawn from the natatorium to maximize its relative humidity and this air in turn flows across the refrigeration coil removing substantial quantities of moisture.

Abstract: A warm air furnace system comprising a closed casing having an air inlet and an air outlet duct, a fan to draw air from the air inlet toward the air outlet duct, a water tank mounted into the warm air furnace casing, a radiator anchored to the warm air furnace casing in proximate register with its air inlet and connected to the water tank by a water intake line and by a water outlet line. A heating element is immersed in the water tank, to heat up to a first threshold temperature the water. A pump recirculates the water from the tank to the radiator and back. A water vapor by-pass tube interconnects the water tank to the air outlet duct, so as to humidify the air warmed by the radiator.

Abstract: The advanced zone damper incorporates an adjustable, spring loaded damper door control which allows any percentage up to 50% of the total air flow to pass through a locked damper door when only two dampers are used in a multizone heating and cooling system. The stated percentage is relative to when two dampers are used, and may vary greatly with system design and the number of dampers and zones in the system. A humidistat and manual control over system functions is also a great improvement over the thermostat control only. Often in a two or more zone system, where the air conditioner is large enough for the building, there may be humidity control problems in any zone which the present invention's controls compensate for by damper doors being unlocked simultaneously while the air conditioner and the heater may both be operating simultaneously so that humidity is removed by the air conditioner while cooling, and heat is added by the heater. This process removes humidity but may not change the air temperature.

Abstract: Bulk cargo which is sensitive to condensate is confined in the cargo area of a seagoing or other vessel in such a way that it comes into direct contact with the walls surrounding the cargo area and is also in contact with moisture-laden air filling the remainder of such area. In order to prevent condensation of moisture on the walls surrounding the cargo area, the temperature of the walls as well as the temperature of air in the cargo area is maintained at a value such that the moisture cannot condense on the walls. This can be achieved by heating the confined air and/or the walls and/or by reducing the moisture content of confined air and/or by a combination of such undertakings.

Abstract: An electronic system to keep the set air temperature inside a motor vehicle constant. It comprises an electronic thermostat, a radio transmitter to transmit the on/off signals of said thermostat, a radio receiver to capture said on/off signals which will drive a switching circuit 10 to turn on/off the vehicle air-conditioner, and a time delay network 9 to delay the on/off actions of said switching circuit. Said electronic thermostat comprises a temperature sensing circuit 1, a temperature setting circuit 2, a humidity sensing circuit 3 to compensate the set temperature, a comparator 4 to compare the two output voltages from said temperature sensing circuit and said temperature setting circuit, and a switching circuit 5 to turn on/off the transmitter. The thermostat and the transmitter are packed together and installed on the motor vehicle dashboard. The receiver and the time delayed switching circuit are packed together and installed under the hood of said motor vehicle.

Abstract: A self-regulating humidity, air temperature, and water temperature control system for indoor swimming pools and other high humidity water chambers comprises a circulating fan, a series of plenums and an air-to-air heat exchanger. Warm, humid air is drawn through one side of the heat exchanger by the fan to precool the exhaust air by thermal exchange with cooler air prior to passage through a dehumidification and cooling coil. The dehumidified and cooled air is then drawn back through the opposite side of the air-to-air heat exchanger to be preheated. A set of dampers operated by an actuator allows air to bypass the heat exchanger to regulate the amount of air that passes therethrough according to pool room air temperature.

Abstract: The heat transfer system is for drying agricultural products, especially tobacco, and comprises a plurality of evaporators associated with a condensor and a compressor in a closed circuit. Air is also circulated in a closed circuit, heat being provided by the condensor for drying the agricultural products, with the air subsequently being cooled and dehumidified by at least one of the evaporators. Humidity and temperature may be monitored and automatically controlled, and an external evaporator may also be provided to dissipate cold and absorb external heat.

Abstract: An integrated precision humidity and temperature control system of research laboratory quality is disclosed in which air flow, water spray and refrigeration apparatuses are sequenced automatically by solid state controls linked in a cooperative manner. Very stable and precise relative humidity and control air temperature constancies are maintainable.

Abstract: A first air conditioner is generally applied to a vehicle including a windshield and a passenger compartment having a front segment and a rear segment. The windshield faces the front segment of the passenger compartment. Air is injected into the front segment of the passenger compartment via a first duct. Air is injected into the rear segment of the passenger compartment via a second duct. A humidifier acts on the air injected into the rear segment of the passenger compartment via the second duct. In a second air conditioner, a humidifier can be selectively activated and deactivated. A temperature control arrangement responsive to activation and deactivation of the humidifier compensates for fluctuations in the temperature of air resulting from changes between activated and deactivated states of the humidifier.

Abstract: A system for controlling the temperature and humidity of an enclosure such as a museum display case continuously extracts air from the enclosure, increases its humidity, cools it to a controlled temperature, at which point its humidity is 100%. The air is then heated and returned to the enclosure. By selection of the controlled temperature the relative humidity of the returned air may be determined.

Abstract: Method and apparatus for controlling environmental conditions in an animal house, and particularly in a poultry house, for producing maximum economic return. The static parameters of the house are determined, and thereafter continuous measurements are made of current inside and outside temperatures. The operator makes periodic assessments of litter condition in the house, and adjusts the target 24-hour average relative humidity to produce the desired litter condition. The system controls the heating and ventilation system to obtain the desired 24-hour average relative humidity while maintaining the optimum temperature conditions in the house for maximum economic return.

Abstract: A humidification system for a building utilizing a hot water heating tank within which is mounted a plenum chamber. Hot water from the tank is directed into the plenum chamber in controlled quantities and is agitated as controlled by a humidistat within the building to either vaporize the water within the plenum chamber or to force pressurized air through the plenum chamber to wet the air. The vaporized water or the wet air is directed from the plenum chamber into the air supply of the building. A water level control in the form of a float valve maintains the level of the water within the plenum chamber at a controlled level. The water may be vaporized by an electrical heater within the plenum chamber or the water may be aerated by air forced through the plenum chamber by a compressor, the humidistat activating the heater or the compressor.

Abstract: A disc drive isolation system including an environment control enclosure and a disc drive isolation module is disclosed. A thermo-electric heat pump is mounted to the enclosure for cooling the interior of the enclosure and a fan circulates air within the enclosure. A humidity sensor controls the heat pump and the fan in response to the sensed humidity of the interior air. First and second temperature sensors control the heat pump andthe disc drive, respectively. The isolation module is disposed in the enclosure and has an outer body and an inner body supported within the outer body with the disc drive mounted within the inner body. The mounting of the inner body within the outer body sequesters the disc drive against vibration and shock applied to the outer body. This arrangement enables almost any disc drive to be operated in an industrial environment independent of the temperature, humidity, cleanliness, shock and vibration characteristics of the environment.

Abstract: An environmental control system has a controller (10) which causes heating apparatus (12A) or ventilation apparatus (12B) to operate through thermostatic dead zone temperature ranges, in response to excessive relative humidity. In the event the heating apparatus (12A) is actuated in response to falling temperatures, ventilation, previously called for by excess humidity, is terminated to prevent inefficiency due to concurrent heating and ventilating. After fresh air of relative lower humidity is introduced by ventilation, the fresh air is heated to further reduce the relative humidity.

Abstract: In a method of operating an air conditioner for supplying an air from the air conditioner to the inside of a chamber, the temperature of the air supplied to the inside of the chamber upon starting the operation of the air conditioner is increased to an aimed temperature while maintaining the supplied air temperature higher than the temperature at the surfaces of the inner wall of the chamber and/or the equipments installed therein but lower than the temperature the dew point for which is lower than the surface temperature, whereby the moistures contained in the air supplied from the air conditioner is prevented from condensating to form water droplets on the inner wall of the chamber and/or the equipments installed therein. The inside of the chamber can be controlled to an aimed air-conditioned state rapidly without causing undesired dewing phenomenon even during winter or like other cold conditions.

Abstract: The present invention relates to humidifiers as used in research and in the calibration of humidity measuring instruments for producing a saturated gas stream. Specifically the invention relates to humidifiers comprising a bubble type and an extended surface type humidifier in gas flow communication one to the other and including temperature control means.

Abstract: An improved, energy-efficient method and apparatus for cooling and conditioning the air being supplied to an air-conditioned area in which the volumetric flow rate of the air being directed through a spray chamber is varied in response to changes in the heat load in the air-conditioned area while the volume of water sprayed by the spray chamber is also varied so as to maintain a predetermined ratio between the volumes of spray water and air flow.

Abstract: A cycle time/temperature controller for a combination corrosion tester includes a device for setting a loop number and a number of repetitions of that loop, a device for setting a sequence of test items within a loop including: a test temperature, a test humidity, and an operating time; the controller also includes a generator for generating an operative signal and a device for enabling the start of operation according to an external start signal and an output circuit for outputting a contact output corresponding to each test item for the set operating time; adjustment outputs for dry bulb and wet bulb temperatures are also provided, each output providing adjustments at the set test temperature and the set test humidity. The controller displays the current loop number and the number of repetitions and also displays: the test item number, the dry bulb temperature, the wet bulb temperature, the wet bulb temperature or humidity, and the time elapsed, during its operation.

Abstract: A central dehumidification system that will work in tandem with a furnace and a central air conditioner or as a single unit. The aforementioned central dehumidification tandem system is separate and independent of the air conditioner. The controls for operation of the central dehumidifier include a control unit which operates in conjunction with the air conditioner such that the central dehumidifier will not operate during operation of theair conditioner.

Abstract: An incubator for laboratory use which includes a housing defining a thermally insulated inner chamber having a controlled gas atmosphere. Devices for sensing characteristics of the incubator chamber atmosphere, and for conditioning the atmosphere, are positioned in a gas recirculation path outside the incubator chamber. The gas atmosphere of the incubator chamber circulates from a chamber outlet in an upper portion of the chamber, through the recirculation path, returning to the incubator chamber through a chamber inlet in a lower portion of the chamber. Included in the recirculation path are a blower for recirculating the chamber atmosphere, a filter, a CO.sub.2 sensor, and a humidifier. A microprocessor-based controller is responsive to the output of the CO.sub.2 sensor to effect the addition of CO.sub.2 to the recirculating gas to maintain a selected CO.sub.2 level in the chamber atmosphere. Upper and lower diffuser plates in the incubator chamber define upper and lower plenums, respectively.

Abstract: An enthalpy control circuit has a humidity responsive capacitive element in one leg of a bridge circuit and a temperature responsive resistance element in another leg. The circuit is powered by a pulsating DC voltage of 1 kilohertz frequency for providing DC output, from an integrator connected to the output of the bridge circuit, indicative of enthalpy. A feedback from an integrator output to the bridge circuit is provided by chopping the DC output into appropriate AC for rebalance. Another feedback circuit around an amplifier provides a reference point compensated for offset voltages brought about by conditions such as temperature affecting circuit components.

Abstract: Energy saving temperature and humidity sensing and control processes, system and apparatuses operate effectively in response to signals received from occupants and to dynamic responses of building and its heating, ventilating and air conditioning system. The disclosed processes, apparatuses and system utilize thermostats equipped with a drift ramping and hold time to save energy; the thermostats only need resetting to a neutral/comfort set point which is accomplished by means of a push button or touch plate.The disclosed systems are pre-programmed and set so that occupants will be confortable although the temperature within the building drifts because the rate of drift is controlled to a gradual and normally unnoticed change.

Abstract: Method and apparatus for controlling environmental conditions in an animal house, and particularly in a poultry house, for producing maximum economic return. The static parameters of the house are determined, and thereafter continuous measurements are made of current inside and outside temperatures. The operator makes periodic assessments of litter condition in the house, and adjusts the target 24-hour average relative humidity to produce the desired litter condition. The system controls the heating and ventilation system to obtain the desired 24-hour average relative humidity while maintaining the optimum temperature conditions in the house for maximum economic return.