A control system and associated methods for an air treatment system. In one aspect, the present invention provides a control system and method for controlling blower speed as a function of separately determined smoke and dust concentrations. In one embodiment, the control system and method provides a variable delayed between changes in motor speed to address undesirable rapid changes between speeds. In another aspect, the present invention provides a system and method for calibrating a sensor to provide more uniform operation over time. In yet another aspect, the present invention provide a system and method for calibrating motor speed to provide more consistent and uniform motor speed over time. The present invention also provides a system and method for tracking filter life by as a function of time, motor speed and/or a sensed variable, such as particulate concentration in the environment.

A method for controlling the opening of a valve (10) in an HVAC system (100) to regulate the flow of a fluid through a thermal energy exchanger (2) of the HVAC system (100) and adjust the amount of energy E exchanged by the thermal energy exchanger (2). According to the method, an energy-per-flow gradient $\frac{E}{}$
is determined, and the opening of the valve (10) is controlled depending on the energy-per-flow gradient $\frac{E}{}.$
The energy-per-flow gradient $\frac{E}{}$
is determined by measuring at consecutive points in time the flow .sub.1, .sub.2, through the valve (10), by determining the amounts of energy E.sub.1, E.sub.2 exchanged by the thermal energy exchanger (2) at these points in time, and by calculating the energy-per-flow gradient $\frac{E}{}=\frac{E_2-E_1}{{}_2-{}_1}$
from the flow .sub.1, .sub.2, and exchanged energy E.sub.1, E.sub.2.

An HVAC actuator coupleable to an HVAC component is disposed in or at an insulated duct. The HVAC actuator may include a housing and a taping flange. The taping flange may be spaced from the outer surface of the duct and adjacent to an outer surface of an insulated layer of the duct when the HVAC actuator is coupled to the HVAC component, and may be configured to facilitate taping of the HVAC actuator to the outer surface of the insulating layer. It may be shaped to provide a front-facing surface that is suitable for receiving tape to provide a seal between the taping flange and the outer surface of the insulating layer. In some cases, the taping flange may extend outward from the housing around the entire perimeter of the housing. The taping flange may be formed integrally with the housing, or it formed separately and coupled to the housing.

An Electronically-Controlled Register vent (ECRV) that can be easily installed by a homeowner or general handyman is disclosed. The ECRV can be used to convert a non-zoned HVAC system into a zoned system. The ECRV can also be used in connection with a conventional zoned HVAC system to provide additional control and additional zones not provided by the conventional zoned HVAC system. In one embodiment, the ECRV is configured have a size and form-factor that conforms to a standard manually-controlled register vent. In one embodiment, a zone thermostat is configured to provide thermostat information to the ECRV. In one embodiment, the zone thermostat communicates with a central monitoring system that coordinates operation of the heating and cooling zones.

A heating, ventilation, or air conditioning (HVAC) system with automated flow direction detection is provided. The HVAC system includes one or more hoses configured to provide airflow from HVAC equipment, a bidirectional pressure sensor coupled to the hoses, and a controller coupled to the bidirectional pressure sensor. The controller is configured to receive a signal from the bidirectional pressure sensor, determine a direction of the airflow relative to the bidirectional pressure sensor based on the signal, correct the signal for a reversed hose polarity relative to the bidirectional sensor based on the direction of the airflow, and perform a control activity using the corrected signal

There is provided a safety system comprising at least one gas detector for detecting presence and concentration of at least one toxic gas inside the target space and for generating corresponding analog signals; (2) an analog-to-digital converter (ADC) connected to the at least one gas detector for converting the analog signals into digital signals; (3) a controller connected to the ADC for receiving the digital signals and generating commands as a function of pre-programmed instructions; (4) at least one exhaust fan connected to the controller for receiving the commands and operating as a function thereof for exhausting the at least one toxic gas outside the target space; and (5) at least one draught fan connected to the controller for receiving the commands and operating as a function thereof for generating a flow of air inside target space.

Embodiments of the invention provide a system capable of reducing negative pressure. The system includes a make-up air system that can be configured and arranged to be installed within a structure, such as a building. The system can also include a pressure switch that is configured and arranged to sense a pressure within an exhaust duct coupled to an exhaust device. The pressure switch can also be configured to communicate an activation signal and a deactivation signal to the make-up air system. In some embodiments, communication of the activation and deactivation signals can be at least partially dependent on the pressure within the exhaust duct. Moreover, the pressure switch can be configured and arranged to be retroactively coupled to at least one of the exhaust duct and the exhaust device.

A mass airflow measuring system includes an air conduit and a sensor assembly mounted to the air conduit, including a unitary one-piece first section which in cross section defines a first channel, a second channel and a wall separating the two channels. A second section has similar components. A unitary one-piece corner section, in cross section includes four legs, each defining a respective channel. A respective leg is mounted in a respective one of the channels of the first and second sections to communicate the sections with each other through the channels defined in the corner section legs. A sample housing is mounted to one of the sections and includes an inlet opening communicating with the first channel and an exit opening communicating with the second channel. A mass airflow sensor communicates with a sample channel defined in the housing.

A control system and associated methods for an air treatment system. In one aspect, the present invention provides a control system and method for controlling blower speed as a function of separately determined smoke and dust concentrations. In one embodiment, the control system and method provides a variable delayed between changes in motor speed to address undesirable rapid changes between speeds. In another aspect, the present invention provides a system and method for calibrating a sensor to provide more uniform operation over time. In yet another aspect, the present invention provide a system and method for calibrating motor speed to provide more consistent and uniform motor speed over time. The present invention also provides a system and method for tracking filter life by as a function of time, motor speed and/or a sensed variable, such as particulate concentration in the environment.

A ventilation system includes first and second blowers connected to a plenum in parallel, with a first motor drive to control a speed of an electric motor of the first blower and a second motor drive to control a speed of an electric motor of the second blower. A controller associated with the first blower is programmed to receive a set point for a controlled variable that is controllable by operation of the first and second blowers, estimate a total air flow required from the first and second blowers to reach the controlled variable set point, calculate a blower speed ratio between a first blower speed and a second blower speed that provides the required total air flow at a minimum power consumption level, and generate commands to cause the first blower and the second blower to operate at speeds resulting in the calculated blower speed ratio.