A HEPA/VOC air handling system having a HEPA air filtration unit, an air handling unit, a fresh air sensor system, a return air sensor system, an air handling air sensor, and a controller.

A method of controlling air quality in an indoor environment of a building is described. The method utilizes a system that comprises a carbon dioxide sensor configured to detect an instantaneous value of carbon dioxide concentration in the air of the indoor environment of the building, a control unit in signal communication with the carbon dioxide sensor, a communication unit for establishing signal communication between the carbon dioxide sensor and the control unit, and a storage unit in signal communication with the control unit. The method comprises the steps of: a) defining and storing in the storage unit, by the control unit, control values of carbon dioxide concentration; b) detecting, by the carbon dioxide sensor, an instantaneous value of carbon dioxide concentration and sending, by the communication unit, the instantaneous carbon dioxide concentration value to the control unit, c) processing, by the control unit, the control values and the instantaneous values of carbon dioxide concentration to generate an output signal representative of the processing performed by the control unit; and d) sending, by the control unit the output signal to a visual and/or acoustic warning unit.

In a system where a plurality of ventilation devices (10) are provided in one room, a control device (5) is provided to control, for the ventilation devices (10) operating, the number of the ventilation devices so that the detected values of the carbon dioxide sensors (13) are lower than the reference value.

An HVAC system within a building including an HVAC device having an air filter, a number of sensors, and a control device. The control device has a processor that is configured to determine a current air quality metric based on air quality measurements received by the sensor. The control device is further configured to calculate an average air quality metric based on the current air quality metric and a set of previous air quality metrics. The control device is further configured to store the average air quality metric. The control device is further configured to generate an air filter type recommendation based on the average air quality metric.

A ventilation fan includes a body unit, which has a fan disposed in a body case and a fan controller operable to control an air volume of the fan. The ventilation fan also includes a sensor module having an indoor environment detecting sensor and a module controller operable to control a detecting operation of the indoor environment detecting sensor. The body unit has a module mount on which the sensor module is mounted and another sensor module can be mounted in place of the sensor module. The module mount is connected to the fan controller. The module controller outputs detection information obtained based on a detection result of the indoor environment detecting sensor to the fan controller, which in turn controls the air volume of the fan based on the detection information inputted thereto.

A ventilation fan includes a body unit, which has a fan disposed in a body case and a fan controller operable to control an air volume of the fan. The ventilation fan also includes a sensor module having an indoor environment detecting sensor and a module controller operable to control a detecting operation of the indoor environment detecting sensor. The body unit has a module mount on which the sensor module is mounted and another sensor module can be mounted in place of the sensor module. The module mount is connected to the fan controller. The module controller outputs detection information obtained based on a detection result of the indoor environment detecting sensor to the fan controller, which in turn controls the air volume of the fan based on the detection information inputted thereto.

An indoor air quality (IAQ) control system for a heating, ventilation, air conditioning, and Refrigeration (HVACR) system including an IAQ monitor that collects air quality data from an air quality sensor of an air quality-controlled space; a controller that manages a remediation device of the air quality-controlled space; and an IAQ management server that generates a biological pollutant estimate based on the air quality data using an algorithm that correlates the air quality data to the biological pollutant estimate, and generates a remediation recommendation. Additionally, a control method includes collecting air quality data from an air quality sensor of an air quality-controlled space using an IAQ monitor; managing a remediation device of the air quality-controlled space using a controller; generating a biological pollutant estimate based on the air quality data using an algorithm that correlates the air quality data to the biological pollutant estimate; and generating a remediation recommendation.

Systems and methods are provided and include a variable frequency drive configured to drive a fan motor of an HVAC system to ventilate an indoor space, the HVAC system having a cooling assembly that includes at least one of an economizer and a compressor. A controller is configured to communicate with the variable frequency drive, receive at least one signal from an occupancy sensing device, determine whether the indoor space is less than fully occupied based on the at least one signal, and control the variable frequency drive to reduce a speed of the fan motor in response to determining that the indoor space is less than fully occupied.

A ventilator includes: a blower unit that exchanges indoor air; a corrected threshold calculation unit that calculates a corrected threshold by correcting a predetermined threshold of CO.sub.2 concentration in the indoor air for changing a ventilation air volume on the basis of a detected outdoor air CO.sub.2 concentration value that is CO.sub.2 concentration in outdoor air detected; and a ventilation air volume control unit that changes the ventilation air volume by controlling an air volume of the blower unit on the basis of the CO.sub.2 concentration in the indoor air and the corrected threshold.

An environmental building sensor, the environmental building sensor including a sensing device configured to measure an environmental condition of a building, an output connection between one or more circuits of the environmental building sensor and an external device, the output connection connected to an input impedance of the external device, and one or more circuits. The one or more circuits are configured to detect a feedback voltage, the feedback voltage based on the input impedance, determine, based on the feedback voltage, whether the external device is configured to receive an analog current input or an analog voltage input from the environmental building sensor, and generate the analog current input or the analog voltage input based on the environmental condition measured by the sensing device and provide the analog current input or the analog voltage input to the external device via the output connection.