Abstract: Disclosed herein is an artificial intelligence device. An an artificial intelligence device according to an embodiment of the present invention includes a communication unit that obtains an external environmental factor and an internal environmental factor collected by a sensor and a processor that provides the internal environmental factors to an environmental factor prediction model to predict a subsequent internal environmental factor and allows a ventilation system and an air cleaning system to operate cooperatively with each other based on the predicted internal environmental factor.

Abstract: An air mixing device mitigates temperature stratification between two incoming air streams by creation of turbulent airflow through an arrangement of channels in the device. The device also provides selective passage of air for incoming airstreams to achieve functionality for damper control typically associated with separate inlet dampers. A method provides for selectively controlled airflow through the device so effective mixing occurs along with an economizer function to control separate airstreams such as outside air and return air. Existing dampers may be integrated with the air mixing device to control airflow in which flow of one airstream through the device increases as the flow of the other airstream is proportionately decreased. A minimum outside air duct can be incorporated in the mixing device to efficiently satisfy building code requirements regarding monitoring and recording of outside air input to air handling units.

Abstract: A method and apparatus for cooling a supply of air is provided. A unit controller receives a cooling demand signal. In response to the cooling demand signal, the unit controller adjusts an economizer according to an economizing function. The economizing function is configured to achieve an initial free cooling target temperature as a discharge air temperature. The unit controller receives an additional cooling demand signal. In response to the additional cooling demand signal, the unit controller reduces the free cooling target temperature. The unit controller adjusts the economizer according to the economizing function, with the economizing function configured to achieve the reduced free cooling target temperature as the discharge air temperature. Additionally in response to the additional cooling demand signal, the unit controller signals a unit to perform mechanical cooling on a supply of air received from the economizer.

Abstract: A method of controlling a discharge air reset in an heating, ventilation, air conditioning, and refrigeration (HVACR system includes determining, by a controller, a space temperature in a conditioned space, a setpoint temperature of the conditioned space, and an operating mode of a variable-air-volume (VAV) box for the conditioned space. The controller determines whether the operating mode of the VAV box matches an operating mode of an HVACR unit. A deviation from the setpoint temperature of the conditioned space for the VAV box for the conditioned is calculated in response to determining the VAV box is in a same mode as the HVACR unit. An average deviation from the setpoint temperature of the conditioned space is calculated. A discharge air setpoint temperature is determined based on the average deviation from the setpoint temperature of the conditioned space. The controller sets the discharge air setpoint temperature of the HVACR unit using the determined discharge air setpoint temperature.

Abstract: A method of controlling a discharge air reset in an heating, ventilation, air conditioning, and refrigeration (HVACR system includes determining, by a controller, a space temperature in a conditioned space, a setpoint temperature of the conditioned space, and an operating mode of a variable-air-volume (VAV) box for the conditioned space. The controller determines whether the operating mode of the VAV box matches an operating mode of an HVACR unit. A deviation from the setpoint temperature of the conditioned space for the VAV box for the conditioned is calculated in response to determining the VAV box is in a same mode as the HVACR unit. A statistical deviation from the setpoint temperature of the conditioned space is calculated. A discharge air setpoint temperature is determined based on the statistical deviation from the setpoint temperature of the conditioned space. The controller sets the discharge air setpoint temperature of the HVACR unit using the determined discharge air setpoint temperature.

Abstract: An apparatus for improving vehicle indoor air quality, may include a controller configured to correct and verify air dust concentration data; determine dust concentration outside a vehicle based on the verified data; and control an operation mode of an air conditioning device according to the determination; and the air conditioning device, wherein an operation of an intake door configured to control an introduction of outdoor air into the vehicle is controlled in response to signals of the controller.

Abstract: An apparatus for improving vehicle internal air may include an air conditioner including an intake door for controlling introduction of external air into a vehicle; an electric dust collection filter to collect fine dust contained in air; and a control device to control operation of the electric dust collection filter and the intake door, based on information about a concentration of fine dust inside the vehicle, a concentration of fine dust outside the vehicle, and a vehicle speed.

Abstract: A welding system including a welding electrode, a closed-loop cooling device, and a vent. The closed-loop cooling device is configured to cool the welding electrode. The closed-loop cooling device includes a pump and a water line. The vent is located along a path of the water line. The vent is configured to release air trapped within the water line.

Abstract: A partition seal portion of a second rotary door is located between an outer door portion and a partition rib. The partition seal member is pressed against a rib tip portion in a door radial direction and moves slidably while being in contact with the rib tip portion in conjunction with a rotation of the second rotary door. Accordingly, an increase of a width in a door axial direction required for a sealing configuration can be suppressed. Therefore, a seal between a side face outlet and a center face outlet can be secured while being preventing a length of a face outlet in the door axial direction from being short.

Abstract: Methods and system for providing heat to a vehicle are presented. In one example, a positive temperature coefficient (PTC) heater provides heat to a passenger cabin and an engine via heating engine coolant. Additionally, a heat pump may supply heat to the passenger cabin via heating the engine coolant.

Abstract: A datacenter or other building includes an intake housing for receiving air from outside of the building. The air is routed through an evaporative cooling system in the housing, resulting in humidified air. The humidified air is mixed with a suitable amount of return air from within the building so as to yield a supply of air having a target relative humidity.

Abstract: A thermal management system for a vehicle includes an enclosure containing an air-handling unit, a first circuit, a second circuit, and a control interface module. The air-handling unit includes a housing and a variable speed blower configured to provide a flow of air through the housing. The first circuit includes a compressor, a condenser in thermal communication with the air-handling unit, a receiver-drier, an expansion valve, and a chiller, in series. The second circuit includes a first loop including the chiller of the first circuit, a second loop including a radiator in thermal communication with the air-handling unit, and a third loop including a heater. The control interface module is configured to control each of the air-handling unit, the first circuit, and the second circuit.

Abstract: A cooling system (20) includes a media exchanger (50), a cooling section (22), and a cooling circuit (120) for circulating a cooling fluid (130) between the media exchanger (50) and the cooling section (22). The media exchanger (50) receives outside air (38) and the cooling section (22) receives return air (32) from and interior space (34). When the cooling fluid (130) circulates into the cooling section (22) via the cooling circuit (120), the temperature of the return air (32) is reduced through indirect heat transfer between the cooling fluid (130) and the return air (32) to produce conditioned air (84). The conditioned air (84) is provided as supply air (46) into the interior space (34). When the cooling fluid circulates into the media exchanger via the cooling circuit, the temperature of the cooling fluid is reduced through direct heat transfer between the cooling fluid and the outside air.

Abstract: A hybrid air handler cooling unit has a bi-modal heat exchanger. In a direct expansion mode or a pumped refrigerant economization mode, the bi-modal heat exchanger is in a refrigerant path in parallel with first and second condenser coils and functions as a condenser coil. In a mixed direct expansion/pumped refrigerant economization mode, the bi-modal heat exchanger is in a refrigerant path in series between an outlet of a pump and an inlet of the first condenser coil and functions as a pre-cooler evaporator coil with return air first flowing across the bi-modal heat exchanger and then across an evaporator coil of an evaporator.

Abstract: Systems and methods for controlling a source of physiological affliction within a moving enclosed structure, such as a vehicle, which defines an interior. The system includes: at least one pressure fluctuation generator, at least one pressure sensor located to sense pressure indicative of the interior of the structure; and at least one controller configured to: determine, from the first pressure sensor information, at least one pressure disturbance within the interior of the structure; and control the at least one pressure fluctuation generator to cancel the at least one pressure disturbance within the interior of the structure. In an example, the at least one pressure disturbance includes infrasonic pressure fluctuations (infrasound). In an example, the physiological affliction includes motion sickness or nauseogenicity.

Abstract: A split air conditioner has a cabinet with a fan and evaporator for mounting within a structure. The cabinet includes a filter or a stacked filter system positioned in the flow path between an air inlet and an air outlet for filtering contaminants from the air. Movable dampers are provided for selectively changing the airflow path to selectively bypass the filter to provide a greater or lesser degree of filtration of the air. Preferably, the filter is a high performance HEPA-like filter having substantially less pressure drop.

Abstract: A computing system for a vehicle is provided. The computing system includes one or more processors for controlling operation of the computing device, and a memory for storing data and program instructions usable by the one or more processors, wherein the one or more processors are configured to execute instructions stored in the memory to estimate at least one characteristic of emissions from at least one forward vehicle expected to enter a ventilation system of an ego-vehicle within a predetermined travel distance ahead of the ego-vehicle and, responsive to one or more estimated characteristics, control the ego-vehicle ventilation system.

Abstract: A split air conditioner has a cabinet with a fan and evaporator for mounting within a structure. The cabinet includes one or more movable dampers or movable filters positioned in the flow path between the air inlet and the outlet for selectively filtering contaminants from the air to provide a greater or lesser degree of filtration of the air. The movable filters include sliding and/or pivot mounting structure which may accommodate stacking multiple filters with different filtering characteristics. The system may operate in a filtering only mode with no cooling, a cooling only mode with no filtering, or a combination of cooling and selective filtering.

Abstract: An air conditioning system includes a cooling unit having a cooling coil and a fan, the cooling unit for cooling recirculated air from a return duct; a bypass duct providing an air pathway bypassing the cooling unit; a phase change material (PCM) module including a PCM and a PCM fan for drawing makeup air over the PCM; and a supply duct fluidly coupled to the cooling unit and the PCM module, the supply duct for supplying conditioned air to a space to be conditioned.

Abstract: A split air conditioner has a cabinet with a fan and evaporator for mounting within a structure. The cabinet includes a filter or a stacked filter system positioned in the flow path between an air inlet and an air outlet for filtering contaminants from the air. Movable filters are provided for selectively bypassing the filters to provide a greater or lesser degree of filtration of the air. Preferably, the filters are high performance HEPA-like filter having substantially less pressure drop.

Abstract: A mechanism is provided for controlling the internal air-quality of a vehicle. Responsive to determining that a speed of a vehicle fails to be above the predetermined low-speed threshold, a determination is made as to whether an internal air-quality from an internal air-quality sensor is better than the external air-quality from an external air-quality sensor. Responsive to the internal air-quality being better than the external air-quality, a ventilation control mechanism is signaled to utilize a recirculating-air mode, wherein the ventilation control mechanism either stays in an already initiated recirculation-air mode or switches to the recirculating-air mode. Responsive to the internal air-quality being worse than the external air-quality, the ventilation control mechanism is signaled to utilize a fresh-air mode, wherein the ventilation control mechanism either stays in an already initiated fresh-air mode or switches to the fresh-air mode.

Abstract: A system and methods providing real-time monitoring, management and control of a variable frequency drive retrofit to a constant volume air handling unit without making significant mechanical or control system changes. Customers and vendors are provided with a more informative and economically attractive air handling unit. The system also provides a finer granularity of control over conditioned air properties such as temperature, humidity and air quality.

Abstract: An air handler and a method of assembling a fan module are provided, in which a case panel may be assembled with a plurality of module frames via a considerably simplified sliding coupling providing excellent hermetic sealing. As such, manufacturing costs may be reduced due to reduction in a number of components, and assembly time may be remarkably reduced due to a reduced number of assembly operations. This advantageously results in reduced labor cost and enhanced air conditioning efficiency.

Abstract: A fresh air heating system includes air intake and discharge chambers, a direct-fired gas burner mounted in a burner chamber in fluid communication with intake and discharge chambers therebetween, and a bypass opening between the air intake and discharge chambers that is selectively closed by a hatch cover having a panel and a peripheral wall extending from the panel.

Abstract: Discussed generally herein are systems and methods for comfort level regulation in a building. A comfort level regulation system for a building can include a plurality of air intakes configured to draw air into the building, and a processor configured to open the one or more air intakes of the plurality of air intakes as a function of an orientation of the building, the location of the air intake relative to the orientation of the building, air temperatures inside and outside the building, and humidity inside and outside the building.

Abstract: In an air conditioning system and a communication method thereof a wireless network may be established between indoor units and a controller or between outdoor units so as to allow communications therebetween, thereby facilitating device addition or device deletion. Also, one or more outdoor units and a plurality of indoor units may be controlled without a dedicated communication line or with using a less mount of the dedicated communication line, and the outdoor units or indoor units may perform communications using one or more communication technologies, such as wireless communication and pipe communication technologies and wireless communication and dedicated line communication technologies, while performing communications with the controller using the wireless communication technology.

Abstract: A system for a server room management includes an air-conditioning control device including: an acquisition unit; a setting unit that sets content for generating supply air at temperature, absolute humidity, and relative humidity within target range, based on outside air temperature and humidity as well as return air temperature; and a controller controlling amount of outside air, amount of return air, control amount of humidifier, control amount of cooler, and amount of air blown by blower, based on the content. If the outside air is within range greater than absolute humidity upper limit, or within range greater than enthalpy upper limit and greater than the temperature upper limit, the setting unit compares outside air and return air, and then determines, in accordance with the comparison, whether to set the content so that the cooler performs cooling by minimizing or maximizing the amount of the outside air.

Abstract: A cooling apparatus and method are provided for cooling an electronics rack. The cooling apparatus includes an air-cooled cooling station, which has a liquid-to-air heat exchanger and ducting for directing a cooling airflow across the heat exchanger. A cooling subsystem is associated with the electronics rack, and includes a liquid-cooled condenser facilitating immersion-cooling of electronic components of the electronics rack, a liquid-cooled structure providing conductive cooling to electronic components of the electronics rack, or an air-to-liquid heat exchanger associated with the rack and cooling airflow passing through the electronics rack. A coolant loop couples the cooling subsystem to the liquid-to-air heat exchanger. In operation, heat is transferred via circulating coolant from the electronics rack, and rejected in the liquid-to-air heat exchanger of the cooling station to the cooling airflow passing across the liquid-to-air heat exchanger. In one embodiment, the cooling airflow is outdoor air.

Abstract: A system and method for energy recovery and humidity control comprises an enclosure (12) with a plurality of ports (86,90,92,94,86) connected to a plurality of ducts (14,16,18,20,22) The system has an enthalpy exchange core (136) exchanging heat and humidity between first air stream (35) and a second air stream (37), and a heat exchange sub-core (134) exchanging heat between the first air stream (35) and a third air stream (39), and fans (34,38,36) for circulating the first air stream (35), the second air stream (37) and the third air stream (39) respectively, and a controller (40) for controlling the fans (34,36,38) and regulating the flows of the first air stream (35), the second air stream (37) and the third air stream (39).

Abstract: The present disclosure provides a method for controlling an economizer of an HVAC system. The economizer has an outside air stream of incoming outside air, a return air stream of return air, and a mixed air stream of mixed incoming outside air and return air that is provided to the cooling unit of the HVAC system. The economizer also includes one or more controllable dampers for controlling a mixing ratio of incoming outside air to return air in the mixed air stream. The control method includes positioning the one or more controllable dampers in first and second configurations such that the mixed air stream has first and second mixing ratios of incoming outside air to return air in the mixed air stream. The method also includes recording first and second measures related to the temperature of the mixed air stream when the dampers are in each of the first and second configurations. First and second measures related to other parameters of the mixed air stream may be recorded as well.

Abstract: The invention relates to a ventilation system for exchanging the air in a room with outside air, which system comprises: A fine wire heat exchanger having a first channel and a second channel, which channels are in heat-exchanging contact with each other, and wherein the first channel has an inlet connected to outside air and an outlet connected to the air in the room, and wherein the second channel has an inlet connected to the air in the room and an outlet connected to the outside air; balancing means for balancing the flow in both channels, such that the heat transfer is maximized. The invention also relates to a combination of a façade, a room on the inside of and adjacent to the façade and a ventilation system, wherein the inlet of the first channel of the system is connected to outside air on the outside of the façade and the outlet is connected to the air in the room, and wherein the inlet of the second channel is connected to the air in the room and the outlet is connected to the outside air.

Abstract: A method for controlling air intake into an air conditioned enclosure includes generating a plurality of sensor output voltages using a NOx sensor. A NOx voltage ratio is calculated from the sensor output voltages. A determination is made when the NOx voltage ratio one of equals and exceeds a NOx threshold. The NOx voltage ratio is reset to a unitary value for a predetermined length of time.

Abstract: An air conditioning control system allows a supply air switching controller to alternately switch outside air control and return air control at a preset switching interval. The supply air switching controller is connected to an air conditioner placed to correspond to each room inside as an air conditioning control subject. The outside air control takes outside air into a temperature/humidity adjustment coil of the air conditioner by opening a first damper provided in the air conditioner in order to adjust an intake volume of the outside air into the air conditioner and by closing a second damper provided in the air conditioner in order to adjust an intake volume of return air from the room inside. The return air control takes the return air from the room inside into the temperature/humidity adjustment coil of the air conditioner by closing the first damper and opening the second damper.

Abstract: A heat exchange type ventilator allows preventing its heat exchanger from being clogged with buildup of ice, and also alleviating cold-draft feeling. This ventilator has an exhaust-air coupling section and a supply-air coupling section, and a ventilating unit which includes an exhaust-air outlet and a supply-air inlet, a motor for driving an exhaust-air fan and a supply-air fan, the heat exchanger for carrying out heat recovery between interior air and outside air, and a cut-off damper for cutting off a supply-air flow in a supply-air channel. Supply-air temperature sensing means for sensing a temperature of the outside air issues a signal, which prompts the damper to cut off the supply-air flow and reduce a volume of the exhaust-air.

Abstract: A technique for climate control of, for example, base station circuitry within an enclosure involves placing base station circuitry within the enclosure and controlling the climate therein. A system according to this technique includes an enclosure suitable for use outside in a wide range of extreme weather conditions. A controller may, for example, control a fan tray with a heater to pull ambient air through a filtration unit, through the fan tray where the air is heated, and through cold start recirculation dampers.

Abstract: A heat recovery arrangement. The arrangement has a housing including a bathroom exhaust inlet, an exhaust outlet, a bathroom exhaust airflow path through the housing from the bathroom exhaust inlet to the exhaust outlet, a return air inlet, and a return air path through the housing from the return air inlet to the exhaust outlet. The housing also has an outside air inlet, a supply air outlet, an outside air path through the housing from the outside air inlet to the supply air outlet; and a heat recovery device extracting heat from the exhaust airflow path and the return airflow path and transferring heat to the outside airflow path.

Abstract: An HVAC system has two variable-air-volume (VAV) systems, a first VAV system for moving fresh air and a second VAV system for moving recycled air. Both the fresh air and recycled air are cooled and dehumidified by a single heat-exchanging coil. The fresh and recycled air streams travel independently in separate ducts until the air streams reach a remotely located mixing box where the air streams mix and ventilate into a room or zone of a building. The HVAC system uses carbon dioxide and temperature sensors in order to regulate the flow of fresh and recycled air to various mixing boxes throughout the building.

Abstract: An air handling apparatus for blending outside and return airflow including a housing having exterior side walls, a top and a bottom and containing first and second inlet regions and a mixing chamber. Outside air flows through a first inlet into the first inlet region while return air flows through another inlet into the second inlet region. There are also first and second damper mechanisms positioned between the first and second inlet regions and the mixing chamber, each capable of adjusting the amount of airflow from the respective inlet region to the mixing chamber. An exhaust fan is mounted on the housing above the second inlet region while an air supply fan is mounted in the housing on the downstream side of the mixing chamber. Heating and cooling coil units can be located downstream of the mixing chamber.

Abstract: A VAV air handler includes a cooling coil with a return air bypass damper for improved dehumidification. The bypass interjects into the supply air a portion of relatively warm, dry return air downstream of the cooling coil. This allows the cooling coil to absorb more latent heat from the incoming outside air and the remaining portion of the return air over a broad range of operating conditions, but especially at low load conditions.

Abstract: A system for monitoring and modifying the quality and temperature of air within a conditioned space includes a blower unit, an optional damper unit for selectively admitting outside air into the conditioned space, a temperature moderating unit and a control unit. The control unit includes a thermostat and conventional temperature control apparatus for selectively activating the temperature moderating unit to maintain the desired temperature in the conditioned space. The control unit also incorporates CO2 concentration measuring and control apparatus which employs a small CO2 sensor. The CO2 sensor includes upper and lower electrodes with an intermediate solid electrolyte. A voltage having a cyclic waveform is applied across the upper and lower electrodes, and the current through the CO2 sensor is read at at least one predetermined voltage representing a CO2 peak. The measured current is representative of the CO2 concentration.

Abstract: A method and system for controlling the temperature of air returned to a conditioning unit in a zoned system is disclosed. The system includes a heating, ventilating, and air conditioning (HVAC) unit that has an economizer. The HVAC unit is connected to a plurality of zones by a supply duct and a return duct. A temperature sensor is provided to sense the temperature of air returning to the HVAC unit. A main control increases the amount of outdoor air entering the system through the economizer when the temperature of the returned air is excessively warm or excessively cold.

Abstract: A strategy for controlling an air side economizer of an HVAC system uses a model of the airflow through the system to estimate the load in two modes when minimum and maximum amounts of outdoor air are being introduced into the building. Transitions between minimum outdoor air and maximum outdoor air usage occur based on those estimated loads, which in a preferred embodiment are cooling loads. The second embodiment of this economizer control strategy uses the model and a one-dimensional optimization routine to determine the fraction of outdoor air that minimizes the load on the HVAC system.

Abstract: A method of controlling the mixing of outside air and return air, entering an air handling unit, through inlets having dampers, the air handling unit having a coil for conditioning the incoming air and a fan for blowing the conditioned air into a conditioned space, the method including measuring the outside air temperature, and return air temperature, and a minimum coil temperature corresponding to a damper position calculating a correlation values from the outside air, return air, and a minimum temperatures determining a correlation function from the correlation value and damper positions, and using the correlation function to calculate the maximum damper position for an acceptable coil temperature.

Abstract: A method and system for controlling the temperature of air returned to a conditioning unit in a zoned system is disclosed. The system includes a heating, ventilating, and air conditioning (HVAC) unit that has an economizer. The HVAC unit is connected to a plurality of zones by a supply duct and a return duct. A temperature sensor is provided to sense the temperature of air returning to the HVAC unit. A main control increases the amount of outdoor air entering the system through the economizer when the temperature of the returned air is excessively warm or excessively cold.

Abstract: An apparatus for controlling temperature and humidity of a conditioned space uses an outside air cooling coil circuit in fluid communication with coolant from a cooling supply. Outside air is introduced over the outside air cooling coil circuit through a damper having open and closed positions. A valve in fluid communication with the coolant supply and the outside air cooling coil circuit has an open setting for permitting and a closed setting for preventing the circulation of coolant through the outside air cooling coil circuit. An HVAC unit control is operatively associated with the valve and the damper for controlling their operation. An occupancy control generates a signal indicating the presence of a human within the conditioned space and is operatively associated with the HVAC unit control.

Abstract: An air-flow management system for controlling the supply air to a motor vehicle passenger compartment is disclosed. The air-flow management system includes a reversible heat pump system for transferring heat energy between an outside environment and a refrigerant. Air from the outside environment, fresh air, and from the passenger compartment, recirculated air, is forced through the air-flow structure by a blower resulting in the transfer of heat energy between the refrigerant and the passenger compartment. A recirculation door provides a means for controlling the mixture of fresh air to recirculated air that flows through the air-flow structure. The position of the recirculation door is selectable by a controller to prevent fogging during the transition from cooling mode to heating mode, minimize the energy expended conditioning the passenger compartment air, and prevent the backflow of unconditioned outside air from the fresh air duct into the recirculation duct.

Abstract: A vehicle air conditioning control system includes an actuator for controlling the position of an outside air intake door and an ambient exhaust gas sensor. A controller of the control system monitors a time rate of change of the degree of uncleanness periodically measured on the basis of the output of the sensor, and commands the actuator to bring the intake door to the fully closed position for the inside air recirculation mode if a first requirement about a previous exhaust gas concentration change and a second requirement about a current exhaust gas concentration change are both met.

Abstract: An enhanced controller for an air conditioning system incorporating mechanical cooling equipment and an economizer, the enhanced controller including circuits for producing signals indicative of commanded changes in temperature of air admitted into the air conditioned space and of a non-temperature parameter, such as carbon dioxide concentration, of air within the space. The signals are supplied to a logic circuit which produces a ventilation damper control signal based on which of the temperature and non-temperature parameters requires greater change. Freeze protection, and maximum and minimum damper position circuits override the basic damper control signal to avoid excessively low space temperatures and to provide air exchange limits.

Abstract: A method of air conditioning system temperature control for a motor vehicle is disclosed. The method includes the steps of measuring an air conditioning compressor discharge pressure and determining if the discharge pressure is greater than a predetermined maximum pressure. The method also includes the step of beginning a forced recirculated air mode if the discharge pressure is greater than the predetermined maximum pressure. The method further includes the steps of determining if the air conditioning system is already in a forced recirculated air mode if the discharge pressure is less than the predetermined maximum pressure, and determining if the discharge pressure is less than a predetermined acceptable pressure if the air conditioning system is already in a forced recirculated air mode. The method still further includes the step of beginning an outside air mode if the discharge pressure is less than the predetermined acceptable pressure.

Abstract: In an air conditioning apparatus for a vehicle, a double layer flow mode is set when the maximum heating state is set during an air outlet mode where both a foot opening portion and a defroster opening portion are opened. During the double layer flow mode, an air passage of an air conditioning case is partitioned into a first air passage through which inside air flows and a second air passage through which outside air flows, in such a manner that the first air passage communicates with the foot opening portion and the second air passage communicates with the defroster opening portion. When the double layer flow mode is set, the maximum rotation speed of a blower for blowing air is reduced by a predetermined level as compared with an entire outside air mode or an entire inside air mode. Thus, heating capacity for a passenger compartment of the vehicle can be improved.