A method/structure for calibrating a product fluid flow device having one or more apertures with aggregate area A.sub.o, where fluid flows along a fluid flow path therethrough in response to pressure differentials ΔP across the apertures. Calibration is effected relative to a calibration fluid flow device having a geometry and operational parameters corresponding to those of the product fluid flow device. A piecewise curved calibration controller establishes calibration conditions and generates a discrete point calibration flow rate (dpCFR) Function by measuring at a sparse set of points in a range of interest and determining a piecewise curved mathematical representation of fluid flow through the calibration fluid flow device. Data representative of the CFR function is transferred to a product blade controller, which processes the mathematical representation, and controls fluid flow through product fluid flow device based on values extracted from the received dpCFR Function.

A UV sterilization system is provided. In some embodiments, the UV sterilization system includes a first UV LED device having a LED circuit and LED emitters. The UV sterilization system can include a sensor electrically coupled to the first UV LED device, the sensor configured to interrupt the operation of the first UV LED device upon detecting movement within an air conditioning system. The UV sterilization system can include a power module electrically coupled to the sensor, where the power module is electrically coupled to a power supply of the air conditioning system. In some embodiments, the air conditioning system can include a packaged terminal air conditioner (PTAC) unit or a split-air air-conditioner system, and the UV sterilization system can be a part of the PTAC unit or split-air air-conditioning system. In some embodiments, the sensor includes a motion sensor and/or an occupancy sensor.

An air conditioning system includes a first unit and a second unit. The space above the ceiling of each of a plurality of clean rooms is included in the chamber as a single space common to a plurality of the clean rooms. The first clean room is higher than the second clean room in air cleanliness.

A control system can provide a linear behavior of airflow as a function of damper position of each zone damper in an HVAC system. The control system incrementally closes each zone damper from a fully open position to a fully closed position, and records static pressure measurements with each change in damper position. Then, using a mathematical model that is derived from the second fan law, a correction is calculated for each damper position of each zone damper based on the recorded static pressure measurements to provide corrected damper positions at which the airflow through the zone damper exhibits a linear behavior. The corrected damper positions are stored and used during an operational cycle of the HVAC system to obtain a precise airflow through the zone dampers.

An air filter for a heating, ventilation and air conditioning, HVAC, system, the air filter comprising: a housing having an inlet opening and an outlet opening, configured for air to flow along an air flow route between the inlet opening and the outlet opening; a supply spool and a take-up spool mounted to the housing on opposite sides of the air flow route; one or more filter guides mounted to the housing between the supply spool and the take-up spool; a strip of filter medium extending from the supply spool to the take-up spool via the one or more filter guides, with a portion of the filter medium extending across the air flow route; and a driver arranged to advance the filter medium to change the portion of the filter medium extending across the airflow route. Air filtration systems, HVAC devices and HVAC systems comprising the air filter.

An air conditioning system includes a plurality of first units each including a first fan configured to blow supply air into a target space. A second unit distributes the supply air to the plurality of first units through a duct. In the second unit, a heat exchanger subjects indoor air and outside air introduced by an outside air supply fan, to heat exchange. The second unit thus generates the supply air and sends the supply air to the duct. A controller controls at least the plurality of first fans so as to inhibit the supply air or the outside air from flowing out of an intake port, by setting a sum of airflow volumes from the plurality of first units to be equal to or more than an airflow volume from the outside air supply fan.

A ventilation unit is for ventilating an indoor space, and incorporates an air cleaning device and mechanical restrictor for controlling a restriction to a flow resulting from a pressure differential across the unit. There is determination of the inside and outside air pressures in the vicinity of the unit and of air quality parameters inside and outside. The air cleaning device and the mechanical restrictor are controlled in dependence on the determined air pressures and air quality parameters. This provides a fan-less, and hence low-power ventilation unit, which relies on throttling the natural air flow across the unit to provide flow control, and hence enable control of air quality. The air cleaning device may be operated only when the flow is into the inside space, saving power.

Logical boundaries enclosing a physical area are defined. A segment of the logical boundaries is defined as a directional gate, wherein traversing the gate into the physical area is defined as an ingress and traversing the gate out of the physical area is defined as an egress. The directional gate is monitored, and ingresses and egresses are detected. An occupancy count of the physical area is maintained, based on monitoring the gate and detecting ingresses and egresses. One or more conditions are tracked in addition to the occupancy count. Artificial intelligence (AI) processing is applied to the maintained occupancy count and the additional tracked condition(s), in real-time as the monitoring, maintaining and tracking are occurring. One or more responsive actions are automatically taken as a result of applying the AI processing to the maintained occupancy count and the additional tracked condition(s).

A building management system for monitoring and controlling HVAC parameters in a building includes one or more processing circuits configured to initialize a predictive model for predicting temperature, pressure, and humidity within a target area and an adjacent area of the building, receive target area data from a target area sensor array configured to measure temperature, pressure, and humidity of the target area, receive adjacent area data from an adjacent area sensor array configured to measure temperature, pressure, and humidity of the adjacent area, execute the predictive model based on the target area data and the adjacent area data to generate a prediction of future temperature, pressure, and humidity within the target area, and control operation of HVAC equipment to maintain the temperature, pressure, and humidity of the target area within a compliance standard.

A heating ventilation and air conditioning (HVAC) system includes an air handling unit having an outlet, at least one zone operably coupled to the outlet of the air handling unit, and at least one indoor air quality sensor operable to monitor an amount of one or more contaminants. The at least one indoor air quality sensor is arranged within the at least one zone. A controller operably coupled to the at least one indoor air quality sensor is configured to detect the occurrence of a fault or an unsatisfied indoor air quality condition and perform diagnostics to determine the cause of the fault or the unsatisfied indoor air quality condition.