A filter section of a heating, ventilation, and air conditioning (HVAC) system includes a plurality of filters arranged in series relative to a flow path of air through the filter section. The plurality of filters includes at least one movable filter transformable between an extended position arranged within the flow path of air and a retracted position removed from the flow path of air. At least one movement mechanism is operably coupled to the at least one movable filter to transform the at least one movable filter between the extended position and the retracted position.

A system includes a concentration sensor, a flow sensor, and a controller. The concentration sensor is configured to measure a concentration of a contaminant in a cabin of an aircraft. The flow sensor is configured to measure a flow rate of air into the cabin. The controller is configured to determine whether a concentration measurement of the contaminant in the cabin exceeds a first concentration threshold. The controller is configured to, in response to determining that the concentration measurement does not exceed the first concentration threshold, control the flow rate of air into the cabin based on a flow rate setpoint. The controller is configured to, in response to determining that the concentration measurement exceeds the first concentration threshold, control the flow rate of air into the cabin based on a flow rate setpoint and a correction factor that is based on a flow sensor tolerance.

Antimicrobial compositions and methods for inhibiting microbial growth are disclosed. The antimicrobial compositions can include an acyl lactylate, a glycol, and a carrier. The carrier can include water. Water can form at least about 90% by weight of the composition.

An air monitoring system includes a housing having a housing inlet and a housing outlet. An airflow is configured to pass through the housing inlet into the housing. A sensor is located within the housing. The sensor is configured to monitor at least one of a frequency of dispensation of an air cleaner from an air freshener and a level of a contaminant in the airflow. The air cleaning system is configured to transmit a sensor signal to at least one of the air freshener and a user device to at least one of: recommend a frequency for air freshening, and adjust a frequency of release of the air cleaner from the air freshener.

The present disclosure relates to a control system for a heating, ventilation, and/or air conditioning (HVAC) system. The control system includes a user interface configured to receive a first input indicative of a first expected operating range of a first parameter in a first zone and to receive a second input indicative of a second expected operating range of a second parameter in a second zone. A first set point for the first parameter is within the first expected operating range and a second set point for the second parameter is within the second expected operating range. The control system includes a controller configured to manage operation of the HVAC system and to provide a first alert in response to the first parameter being outside of the first expected operating range and a second alert in response to the second parameter being outside of the second expected operating range.

When a controller determines that a leakage of refrigerant occurs, the controller executes a control of rotating an air-sending fan at high rotation speed. After the control, the controller executes a control of stopping rotation of the air-sending fan or reducing a rotation speed of the air-sending fan in accordance with a result of detection by a first refrigerant sensor provided in a lower portion of a heat exchanger chamber. Thus, the air-sending fan is prevented from continuing the rotation at high rotation speed. Therefore, an indoor unit for an air-conditioning apparatus is excellent in safety and is capable of avoiding feeling of discomfort of a user due to the high-speed rotation of the air-sending fan.

There is an air purification system comprising, at least one housing, at least one pump configured to pump a biological purification solution through the housing. at least one fan configured to draw air into the housing. Air is cleaned and flows in a direction transverse to the direction of flow of the enhanced fluid. There can be at least one sensor which determines a level of biological impurities or contaminants in the air. There can also be at least one controller configured to control a rate of movement of said at least one fan based upon a level of impurities detected by the sensor. In at least one embodiment there can be at least one clean room which is configured to clean the air through at least one air purification system comprising one having an enhanced fluid or one that uses UV light and at least on HEPA filter.

A heating, ventilation and air conditioning (HVAC) unit can flow conditioned air into an indoor space through a first flow pathway, and receive returned air from the indoor space through a second flow pathway. A sensor module is positioned in the second flow pathway to receive the return air from the indoor space and determine that a quantity of volatile organic compounds (VOCs) in the return air exceeds a threshold VOC quantity. In response, the HVAC unit can flow a quantity of the return air out of the second flow pathway and into the atmosphere, and draw, into the second flow pathway, an equal quantity of air from the atmosphere. The HVAC unit can flow a remainder of the return air and the drawn quantity of air from the atmosphere into the first flow pathway to be conditioned and flowed into the indoor space.

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.

Computer-implemented systems and methods for estimating a replacement status of an HVAC air filter. Outdoor weather data (e.g., outdoor temperature information), is obtained. A Total Runtime Value of the HVAC system is determined based upon the obtained outdoor weather data. Finally, a replacement status of the air filter is estimated as a function of a comparison of the Total Runtime Value with a Baseline Value. By correlating air filter replacement status with an estimated runtime of the HVAC system, a credible predictor of air filter usage is provided. By estimating fan runtime based on easily-obtained outdoor weather data, the methods are readily implemented with any existing HVAC system and do not require installation of sensors or other mechanical or electrical components to the HVAC system.