Architectures and techniques are presented that can more efficiently route excess air flow by intelligently selecting the zones to which the excess air flow is to be routed. Excess air flow results from an HVAC device providing (e.g., at a minimum setting) a volume of air that is greater than what is demanded by a zone that triggers activation of the HVAC device. As one example, excess air flow can be routed to a zone or zones that are determined to be most likely to trigger a subsequent activation condition that would cause the HVAC device to be activated again at a future time.

A variable air flow air conditioning (HVAC) system is provided, along with methods of use thereof. In example embodiments, one or more variable speed fans or air-moving devices are in communication with ducts connecting one or more zones of a structure or other space to be air conditioned. Zone temperature sensors and air flow measurement are provided to obtain particular measurements relative to the zone it is serving while communicating with a central control. Optionally, a distributed control system can be provided such that zone sensors communicate with both the central control and a respective zone controller. The control system collects and processes multiple data sets to dynamically and proportionally adjust the volumetric air flows of each of the zones to satisfy any loads or heating/cooling demands while also maintaining a net volumetric air flow across a coil of the indoor heat transfer unit within a preset range.

A filter apparatus includes a filter, a pipe, a blower that sucks, through the pipe, air filtered by the filter, a wind speed sensor that measures a mass flow rate of gas flowing through the pipe, a temperature sensor that measures a temperature, a pressure sensor that measures an air pressure, and a processor that controls suction of the blower, based on the measured air pressure, the measured temperature, and the measured mass flow rate.

A method for indicating to a user the expected time for an air purifier to achieve a target level of pollution in a room by: (A) acquiring the current level of pollution (CP) in said room; (B) acquiring current air flow speed (CAFS) through said air purifier; (C) comparing the current level of pollution (CP) with a pre-determined target level of pollution (IP); (D) calculating the expected time (T) required to reduce current pollution (CP) to said target level of pollution (IP) at current air flow speed (CAFS); (E) indicating said expected time (T) required to reduce current pollution to said target level of pollution at current air flow speed to a user; and (F) repeating steps (A) to (E).

Devices, methods, and systems for detecting airflow and temperature conditions of a fire sensing device are described herein. One device includes an airflow sensor and a controller configured to receive a measurement from the airflow sensor, compare the measurement to a baseline range, and transmit a message responsive to the measurement being outside of the baseline range.

A method for providing filtered air to a zone of a building includes operating an air handler to pass unfiltered air through a filter and output filtered air to the zone of the building. The method includes determining an amount of filtered air provided to the zone of the building by the air handler. The method includes determining if additional air filtration is required to satisfy at least one of a desired amount of clean airflow or a desired reduction of a risk of infection. The method includes activating an in-zone filtration device and operating the in-zone filtration device to draw air from the zone into an inner volume, filter the air, and recirculate the filtered air to the zone of the building in response to determining additional air filtration is required.