Abstract: When there is no occupant in seats other than a driver seat during a foot mode, an air-conditioning controller executes a single seat concentration mode to prevent blowing of warm air to a passenger seat and a backseat by closing foot outlets on a passenger seat side and a backseat side. In this case, in order to maintain an air volume blown from the foot outlet on a driver seat side when the controller changes the mode from the normal foot mode to the single seat concentration mode, the controller sets a blower level to be lower than in the case of the normal foot mode with respect to the same target blown air temperature. Thus, an electric power consumed by an electric motor of a blower can be reduced, thereby realizing energy saving.

Abstract: An energy saving air quality control system modulates supply fan speed by use of controlled, variable-frequency drive controls for automatic dampers or suction pressure to maintain adequate air flow across the evaporator coil at partial cooling loads. Demand ventilation in the system balances air quality and energy consumption by controlling the outdoor air damper in response to indoor CO2 levels.

Abstract: An air conditioner managing apparatus includes a storage unit configured to accumulate operation data about numerous indoor units, a first screen generating unit, a second screen generating unit and a display switching unit. The first screen generating unit is configured to generate a first screen on which a plurality of the numerous indoor units with a problem can be visually verified based on the operation data. The second screen generating unit is configured to generate a second screen on which the operation data related to a specific one of the plurality of indoor units can be visually verified. The display switching unit is configured to switch to the second screen relating to the specific one of the plurality of indoor units when the specific one of the plurality of indoor units displayed on the first screen is selected and an input of a prescribed button is accepted.

Abstract: A microcontroller for controlling an actuator includes a single wire controller configured to receive data and power from a base station through a single wire bus, where the single wire bus is part of a power and signal cable configured to connect the microcontroller to the base station. The microcontroller also includes a peripheral interface controller (PIC) microcontroller configured to transmit data signals to and receive data signals from the single wire controller, where the PIC microcontroller is configured to receive reduced voltage level from a power wire of the power and signal cable, to measure the voltage level and to communicate the measured voltage level to the base station through the single wire bus.

Abstract: An air heater includes a bell housing semi-attached to an exhaust fume output manifold of an engine of a vehicle for collecting hot air, preferably during starting, linked by an air hose to a small turbine or an extractor which forces air into vehicle's compartment, to front and rear screens or to exterior rear view mirrors by way of a suitable pipe or several of these; a thermostat for shutting off the air heater and opening up or turning on the vehicle's conventional heater by means of a manual or electrically-operated butterfly valve, shutting off the turbine. It includes a bell housing semi-attached to the exhaust fume output manifold of an engine of a vehicle for collecting hot air, preferably during starting, linked by an air hose to a small turbine or an extractor which forces air into the vehicle's compartment.

Abstract: A temperature moderation system with temperature difference considerations between indoors and outdoors for facilitating an air conditioner in operation control, comprises an indoor unit and an outdoor unit connected with each other. The outdoor unit has an outdoor temperature detection element. The indoor unit has a processor for generating and sending a target temperature to the air conditioner for operation control. The target temperature is one selected from the indoor setting temperature and a pre-set temperature, which is more approximated to the outdoor temperature.

Abstract: HVAC systems, including various HVAC system components, and methods for manufacturing the same are disclosed for controlling airflow into a building. Embodiments of the HVAC systems include apparatuses for controlling the volumetric airflow moving through at least one HVAC system component using a measurement device, for example an airflow detector, a regulator, for example a damper or blower, and a controller, where the controller receives input from the measurement device, manipulates the input with a control algorithm, and sends output commands to the regulator. Further embodiments include apparatuses and methods for development of the control algorithm by testing a similar HVAC system component, measuring the actual volumetric airflow through the HVAC system component, and comparing the actual volumetric airflow with the airflow measured by the measurement device. Still further embodiment include forming a plurality of similar HVAC components that each control airflow without requiring further testing.

Abstract: Control systems for recovery wheels, ventilation systems with recovery devices, buildings having ventilation, and methods of controlling recovery wheels and controlling or modifying ventilation systems. A parameter of ventilation systems or recovery devices, such as the speed of a recovery wheel, may be controlled as a function of pressure, differential pressure, flow rate, or fan speed, for example, to provide appropriate purge flow to maintain purge effectiveness and limit the carry-over of contaminants from a return/exhaust airstream to an outside/supply airstream, for instance, in a variable air-volume system. A purge angle may be set at a minimum position commensurate with a maximum flow rate and recovery-wheel speed may be reduced at lower flows to maintain purge effectiveness. In some embodiments, temperature and humidity are measured, and wheel speed is also controlled as a function of these measurements.

Abstract: In a method for operating a fluid moving device, the fluid moving device is operated under one of a local mode where the fluid moving device operates autonomously and a global mode where the fluid moving device operates based upon instructions received from a global controller, and where the fluid moving device is operated under the local mode as a fail-safe operation to the global mode.

Abstract: Electrical load spreading arrangements reduce peak power demand. An enclosure houses an electronic circuit board, which receives at a first input terminal a first thermostat control signal from a thermostat intended to control a first air conditioning unit and at a second input terminal a second thermostat control signal from a thermostat intended to control a second AC unit. A controller on the circuit board is programmed with instructions stored in a memory coupled to the controller causing the controller to monitor the first and second input terminals to determine the timing and duration of the thermostat control signals passed to the output terminals for activating or deactivating the AC units such that overlapping operation of the AC units is reduced particularly during peak demand periods. A similar arrangement may be applied to a broader class of HVAC equipment, including water heaters, for example.

Abstract: A touch-sensitive interface (7) for a heating and/or air-conditioning device (9) of a motor vehicle (5) includes at least one heat-sensitive wall (11a, 11b) accessible to the fingers (13a, 13b) of a user and designed to be heated and/or cooled by a heating and/or cooling element (15) arranged behind this wall (11a, 11b) so that, upon contact with the wall, the user has a feeling of hot or cold.

Abstract: An HVAC system includes a grid of intersecting ducts having one or more inlets, outlets, and intersections. Air may be received into the inlets and directed through the outlets into one or more zones of a building. One or more HVAC units may be connected to the inlets and mechanical valves may be located at the intersections to control the air flow through the grid. A control system may be provided to control the temperature of each zone by adjusting the mechanical valves (and/or turning selected HVAC units “on” or “off”). In certain embodiments, the HVAC system includes at least one reading device to read temperature preference information associated with an occupant of a zone. The control system may then align the temperature of the zone with the temperature preference information when the occupant is inside the zone. A corresponding method and apparatus are also disclosed herein.

Abstract: A system and method to control environmental parameters of pre-defined zones within an environment using an electronic controller. An electronic controller monitors a loop temperature of a loop field of a geo-thermal heat pump as detected by a temperature sensor connected to the loop field. The electronic controller selects a staging combination of the geo-thermal heat pump and an auxiliary HVAC equipment based on at least the loop temperature. The electronic controller activates the selected staging combination, to modify at least a portion of the environmental parameters, using non-proprietary activating signals provided by the electronic controller.

Abstract: HVAC systems, zone control units, and control systems are provided. An HVAC system employs distributed zone control units that provides for localized air recirculation. A zone control unit can include a return air section that receives return air from serviced building zones and can mix the return air with a supply of outside air. The mixed air can be heated and/or cooled by the zone control unit and discharged to serviced building zones in a controlled manner. An exhaust air system can be used to extract air from serviced building zones. An HVAC zone control unit can include a local control unit with an Internet protocol address. The local control unit can include a memory and a processor for storing and executing a control program for the zone control unit. The control program can control of the zone control unit in response to commands received via the Internet.

Abstract: A refrigerator unit is configured for a container in which it is possible to know the quantity of air that is ventilated. The refrigerator unit is equipped with a ventilation mechanism, an opening degree detecting mechanism, and a recording unit. The ventilation mechanism ventilates the air inside the container. The opening degree detecting mechanism acquires ventilation data related to the quantity of air ventilated by the ventilation mechanism. The recording unit records the ventilation data acquired by the opening degree detecting mechanism.

Abstract: A hybrid solar attic vent comprising a housing configured to be mounted on the roof or in the gable of a building in communication with the attic of the building. A photovoltaic solar panel is positioned to be exposed to sunlight and to power the attic fan when sufficient sunlight is present. An alternative source of energy, which may be the building's AC power, is connected to the fan through an electronic control module. The control module monitors the output of the solar panel and switches the fan's power source from solar power to the alternative source of energy when the solar panel produces insufficient electrical energy to power the fan. A thermostat allows operation of the fan by the alternative power source only when the temperature in the attic is above a predetermined threshold.

Abstract: The present invention provides methods, devices and systems for improving air quality. In one exemplary embodiment, the invention provides an air quality control system for maintaining or improving air quality within a room. The air quality control system includes a fan in fluid communication with a room. The fan is configured to vent air from within the room to control air quality therein. The air quality control system further includes a fluid flow sensor located proximate to a conduit. The fluid flow sensor is in communication with a wireless transmitter configured to generate a signal based upon fluid flow through the conduit. The air quality control system also includes a receiver configured to receive the wireless signal generated by the wireless transmitter, wherein the receiver is in communication with the fan to cause activation of the fan based upon the signal generated by the wireless transmitter.

Abstract: A wiring connector housing including a housing body having first and second ends and at least one interference tab extending outwardly from the second end is provided. The wiring connector housing further comprises spaced apart channels located through the housing body extending from the first end to the second end with the first end of the channels each configured to receive a quick connector therein. Each of the second ends of the spaced apart channels being located to register with and receive corresponding quick connect terminals therein. The at least one interference tab is configured to contact an isolation ridge of an electrical relay and thereby prevent the second ends of the spaced apart channels from being improperly registered with the corresponding quick connect terminals.

Abstract: A control method and associated component configuration provide cooling for components within a wind turbine structure, such as a tower or nacelle. A recirculating airstream of internal air is established in the structure. For a defined set of operational conditions of the wind turbine that affect a required cooling capacity within the structure, the recirculating airstream is controllably augmented with external air to increase cooling capacity of the recirculating airstream. The amount of external air introduced into the structure is balanced with the amount of relatively hotter internal air within the structure so as to achieve a desired balance of temperature and relative humidity within the structure.

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: Certain disclosed embodiments pertain to controlling temperature in a passenger compartment of a vehicle. For example, a temperature control system (TCS) can include an air channel configured to deliver airflow to the passenger compartment of the vehicle. The TCS can include a one thermal energy source and a heat transfer device connected to the air channel. A first fluid circuit can circulate coolant to the thermal energy source and a thermoelectric device (TED). A second fluid circuit can circulate coolant to the TED and the heat transfer device. A bypass circuit can connect the thermal energy source to the heat transfer device. An actuator can cause coolant to circulate selectively in either the bypass circuit or the first fluid circuit and the second fluid circuit. A control device can operate the actuator when it is determined that the thermal energy source is ready to provide heat to the airflow.

Abstract: A ventilation system and a controlling method of such a ventilation system are provided. The ventilation system may exhaust internal air from and draw fresh external air into a designated space. When an outdoor temperature is below a freezing point, some of the internal components of the ventilation system may be damaged due to the low external air temperature. This ventilation system controls operation of a supply fan and/or an exhaust fan based on the temperature of supplied and/or exhausted air to prevent such damage.

Abstract: The present invention is directed to a multiple zone climate control system which includes a HVAC unit that supplies conditioned air to more than one zone, a zone controller in each zone, a central controller, one or more air flow rate regulating devices in each zone, and a digital wireless network connecting the air flow rate regulating devices, zone controllers and the central controller. The multiple zone climate control system is capable of energy efficiently regulating temperature in each zone independently as well as providing other air conditioning functions such as humidifying, cleaning and filtering air in each zone independently. The multiple zone climate control system can be installed in a single zone climate control system to convert it into a multiple zone climate control system.

Abstract: Systems and methods are disclosed for reducing the usage of a ventilation system. For example, one or more of the exemplary systems comprise a thermostatic controller that has at least two settings for the delay occurring between turning the ventilation system off and then turning the system back on. One setting being for a first interval and at least a second setting for a second interval that is longer than the first interval. A processor is in communication with the thermostatic controller and is configured to evaluate one or more parameters including at least the temperature outside the structure conditioned by the ventilation system. The processor is further configured to determine whether to adopt the first interval or the second interval based upon the values of the parameters.

Abstract: Systems and methods to regulate the amount of outdoor air that is introduced into a building. These systems and methods determine the mechanical load requirements based on adaptive control functionality. These systems and methods utilize extremum seeking control logic to vary the flow of outdoor air into the building in response to these load determinations.

Abstract: A method for providing energy-efficient temperature and humidity control with uniform ventilation air distribution in a constant-volume zoned heating and cooling systems. The method utilizes an air-to-air heat exchanger that regulates the temperature of the supply air to a space, using the temperature differential between supply air and return (room) air and regulating the flow of return air through the heat exchanger.

Abstract: A zone-control unit adapted for facile inclusion in a building's ductwork includes a mechanical terminal unit, inlet and outlet piping assemblies that are mechanically coupled together. The structure also includes at least one handle so the zone-control unit may be conveniently and safely handled both during shipping, and during installation into a HVAC system. Prior to installation into a HVAC system the fully-functional zone-control unit also includes a pair of caps respectively sealing the ends of the piping assemblies, and a pressure gauge for sensing pressurization of the piping assemblies and coil which the caps seal. Sealed in this way a pressure gauge permits testing to assure that the piping assemblies and coil are leak free, and readily assessing that zone-control units remain leak free until they are about to be installed into a building's HVAC system.

Abstract: A dust-cleaning device for a computer and a method using the same that utilizes a computer fan are disclosed. The computer is a laptop computer, a desktop computer, or a server. The method comprises: determining if a temperature of an electronic component is higher than a specific temperature; and if so, then reversing the computer fan for a specific amount of time as indicated by a timer.

Abstract: The present invention provides an airflow control loop that uses averaged airflow measurements without the problems that are normally encountered with averaging measurements, such as the delay introduced into the airflow control loop. This is accomplished, in the present invention, through a predictive control scheme. The predictive control scheme of the airflow control loop calculates the damper sensitivity, calculates the damper runtime needed to achieve setpoint, and then runs the damper for the determined period of time. In addition to the unique airflow control loop used to maintain the constant airflow into the room, the present invention also implements a digital form of proportional, integral, and derivative (PID) control to maintain the room temperature. The digital form of PID control uses non-linear gains which vary according to how far the measured temperature is from setpoint.

Abstract: A device for temperature regulation of sections of the interior of an aircraft includes a controlled mixer valve for the mixing of engine bleed air and air that is cooler than the engine bleed air in order to obtain pre-tempered mixed air flowing out of the mixer valve; a distribution line connected to the outlet of the mixer valve which is connected to the respective sections by at least two supply lines; individual heating units assigned to the respective sections; sensors assigned to the individual sections for the respective actual temperatures; transmitters for the respective nominal temperatures; and a regulator unit which controls the mixer valve dependent upon the respective nominal temperatures and the respective actual temperatures in the individual areas.

Abstract: The described method and apparatus pertains namely to the HVAC (Heating, Ventilating, and Air Conditioning) industry, though its many functions extend into any and all forms of air-fluid movement, metering, distribution, and containment. Essentially, the scope of operation of the method and apparatus encompasses all forms of scientific and engineering measurement dealing with fluid dynamics, fluid statics, fluid mechanics, thermal dynamics, and mechanical engineering as they pertain to precise, articulated control of air-fluid distribution and delivery. The described method and apparatus offers complete, comprehensive, and correct utilization of air-fluid movers and terminal devices under unique sensor logic control, from initial lab testing stages through to equipment cataloguing, selection, design and construction of any and all air-fluid distribution systems in entirety, whereas previously there was no such cohesive, total and terminal method of control for these systems or their components.

Abstract: A method and apparatus are provided for detecting a temperature of a cabin within an airplane. The method includes the steps of providing a temperature sensor, enclosing the temperature sensor within an enclosure, coupling an inlet of the enclosure to the cabin of the airplane and an outlet to an air conditioning air return of the airplane and disposing a filter over the inlet.

Abstract: A method, system, apparatus, and device to provide an effective, automatic means to effect exhaust, supply, or balanced ventilation, or a combination thereof, by automatically activating a ventilation fan for the selected operation time per cycle interval based on prior fan operation due to automatic cycle operation and user demand. In a second embodiment the ventilation fan controller automatically activates said ventilation fan in conjunction with operation of a blower of a central air conditioning system. In a third embodiment, the ventilation fan controller also automatically operates the blower for the selected operation time per blower cycle interval, including operation due to thermostat and/or humidistat demand and operates the ventilation fan in conjunction with operation of the blower and/or for the minimal time selected per interval, including operation due to user demand. Optionally, a position of an outside air intake damper is controlled in conjunction with activation of the blower.

Abstract: In an energy efficient building, a thermostatic controller receives temperature and humidity input signals indicative of an inside, outside and air mass buffer. According to one or more algorithms, the thermostatic controller controls the operations of various actuators, such as blower speed, a fresh air intake vent damper, an exhaust vent and a heat pump, so as to adjust the internal climate of the energy-efficient building towards a control point (e.g., an inside temperature and humidity comfort level).

Abstract: To provide a positioning system that clearly defines a disposition of a base station for identifying a position of a radio set. While a wireless base station 1 that transmits and receives a distance-measuring signal to and from a terminal 2 to be measured by wireless communication is disposed at each corner forming an equilateral triangular, the length of each side of the equilateral triangle is made to be a maximum communication distance of the wireless base station 1.

Abstract: A system and method to control environmental parameters of pre-defined zones within an environment using an electronic controller are disclosed. The system includes a non-proprietary electronic controller which enables a weighting value to be assigned to each zone within the environment. The electronic controller also detects any zone service calls from sensor devices associated with each of the zones and determines a cumulative weighting value in response to the detected zone service calls. The electronic controller selects an equipment staging combination from at least two possible equipment staging combinations in response to thermal capacity, and an air handler stage is selected in response to at least the cumulative zone weighting value.

Abstract: A refrigerator unit is configured for a container in which it is possible to know the quantity of air that is ventilated. The refrigerator unit is equipped with a ventilation mechanism, an opening degree detecting mechanism, and a recording unit. The ventilation mechanism ventilates the air inside the container. The opening degree detecting mechanism acquires ventilation data related to the quantity of air ventilated by the ventilation mechanism. The recording unit records the ventilation data acquired by the opening degree detecting mechanism.

Abstract: A zone control panel for use with an HVAC system having zone control and a variable speed blower, and a method for controlling a fluid temperature conditioning device. In one aspect, the zone control panel includes a plurality of thermostat terminals for receiving thermostat signals, a plurality of damper terminals for transmitting damper control signals, and one or more terminals for transmitting signals to control a fluid temperature conditioning device having a variable speed blower. The zone control panel also includes a blower terminal for transmitting a signal to a dehumidification terminal associated with the fluid temperature conditioning device, where the dehumidification terminal is labeled or indicated for use with a dehumidification operating mode or for initiating a dehumidification operating mode of the variable speed blower.

Abstract: A VAV solid state VAV fan series and parallel fan controller for controlling a fan and at least one stage of reheat in a ventilation system in response to signals from an external VAV controller is disclosed. The VAV solid state VAV fan series and parallel fan controller is in connection with at least one transformer, external VAV controller, fan, speed adjuster, reheat device, and circuit breaker for conditioning an air volume. A sensor associated with the external VAV controller constantly monitors room temperature and generates signals for the controlled operation of the device. The preferred invention has a plurality of terminal blocks with each terminal block having single point connections. The invention includes at least one fan relay that initiates power to start the fan and at least one reheat relay that initiates power to reheat device in stages in response to the signals from the external VAV controller.

Abstract: An air conditioner and a method for controlling the air conditioner are provided. The air conditioner may include an air-conditioning device having a variety of components that provide air-conditioning of an indoor space, an input device that receives signals to manipulate the air-conditioning device and signals to select a sleep mode, and a controller that, when the input device receives a signal to select the sleep mode, controls the air-conditioning device to perform a rapid eye movement sleep operation at least one time to air-condition the indoor space at a temperature higher than a temperature that is set in accordance with the sleep mode.

Abstract: A system for monitoring, managing, and/or operating a plurality of farm houses on a plurality of farms. The system includes a controller and/or a monitor box in the farm house and a computer in communication with the controller for controlling and adjusting various parameters of the farm house or with the monitor box for monitoring the farm house. The system also includes a computer at an integrator's office that is operable to monitor and/or control various parameters from the farm house remotely. These parameters enable the integrator to coordinate operations with processing plants, feed mills, field service and hatcheries. It also enables the integrator to prepare various data reports for use by the integrator or others.

Abstract: A heating and cooling system for a multi-level space is provided that comprises at least one lower level return air duct and at least one upper level return air duct, and a thermostat for controlling the operation of the heating or cooling system through either a low voltage cooling activation signal or a low voltage heating activation signal.

Abstract: Distributed nodes, such as intelligent register controllers, of a heating, ventilating and/or air conditioning (HVAC) system wirelessly communicate with each other on a peer-to-peer basis, forming a network, and collectively control the HVAC system, without a central controller. The intelligent register controllers collectively control the amount of conditioned air introduced into each region. Each node may base its operation at least in part on information about one or more (ideally all) of the other nodes.

Abstract: The invention is related to a method and an apparatus for controlling a ventilating system or an air conditioning system of buildings. This controlling is used predominantly in industrial real estates and serves for the establishment and maintenance of the desired room conditions. The method for controlling a ventilating system or an air conditioning system according to the invention uses the air density as the essential parameter for the controlling. The air density depends on the temperature, the air humidity and the air pressure. The air density difference between the introduced air and the room air is kept small.

Abstract: [Problem] To propose a control apparatus for an electric train, in which the regenerative energy of a DC power feed circuit can be consumed without disposing the brake chopper or electric-double-layer capacitor of the DC power feed circuit. [Means] A control apparatus for an electric train according to this invention includes an AC electric motor which drives the electric train, and a variable-voltage variable-frequency inverter which controls the AC electric motor, and further includes an auxiliary power source device connected to a DC power feed circuit, and load control means for controlling a load connected to the auxiliary power source device, wherein the load control means receives an inverter state signal representative of an operation state of the variable-voltage variable-frequency inverter from the it, and the load control means controls the load in accordance with the inverter state signal.

Abstract: Sensors, apparatus and methods are disclosed for detecting airflow direction between two volumes. The preferred airflow sensor includes a tube for conducting an airflow stream between the volumes, a first temperature sensor sensing ambient temperature in the first volume and a second temperature sensor sensing temperature of the airflow stream in the tube. A heat source heats air in the tube adjacent the end thereof communicating with the second volume and a comparator receives and compares output signals from the temperature sensors, providing an output indicative thereof. Various means are provided responsive to the output advancing appropriate response thereto. The disclosed sensors, apparatus and methods are particularly well adapted for indicating positive and negative pressure differentials at flues associated with combustion appliances.

Abstract: A system and method for controlling temperature of an energy storage device of a vehicle via a movable device. The method includes determining a set of inputs, the set of inputs including a representative temperature of the energy storage device and a cabin temperature corresponding to an operator cabin. The method further includes generating a control signal based at least in part on the set of inputs, outputting the control signal to the movable device, and modifying a variable rate of movement of the movable device in response to the control signal such that a corresponding variable amount of operator cabin air is moved past the energy storage device.

Abstract: A thermostat is provided that receives one or more inputs from at least one heating system of a climate control system, and initiates an appropriate action in response to the input. The thermostat can turn off a heat pump providing substandard heat and responsively turn on a fuel-fired auxiliary furnace. The thermostat may discontinue further operation of the auxiliary furnace upon receiving an operating error signal associated with the auxiliary furnace, and responsively turn on the heat pump to provide for continued heating. The thermostat may also discontinue operation of the fuel-fired furnace and turn on a circulating fan in response to an input signal indicating a furnace high-temperature or a carbon monoxide presence.

Abstract: A control system for controlling delivery of either heated or cooled water over a common water line to a plurality of heat exchangers. The control system includes a hydronic system controller which polls the heating or cooling demands of zone controllers controlling the respective delivery of water to the individual heat exchangers. The hydronic system controller is operative to implement a changeover between delivery of heated water to delivery cooled water or vice versa. The implemented changeover preferably includes checking the temperature of the water being returned to the source or sources for heating or cooling the water as well as defining a changeover time period which must occur in the event that the temperature of the water in the return line is not within a predefined range.

Abstract: A control strategy for supply fans in constant-volume heating, ventilating, and air-conditioning (HVAC) systems that reduces the speed of the fan at part-load conditions is provided. The invention consists of a constant-volume HVAC system, wireless discharge air temperature sensors, wireless hot source and cold source temperature sensors, and a wireless controller coupled to a fan modulation device. The controller includes a finite state machine that switches between a high-temperature control mode and a low-temperature control mode. The controller also includes a calculator that calculates a high temperature setpoint and a low temperature setpoint as a function of the hot source and cold source temperatures. In high temperature control mode, the controller compares the maximum discharge air temperature with the high temperature setpoint, and it commands the fan modulating device so that the maximum discharge air temperature remains close to the high temperature setpoint.