A method comprising detecting an indoor carbon dioxide level; detecting an outdoor fine dust level; driving an air supply fan and an exhaust fan such that an air supply amount of the air supply fan is greater than an exhaust amount of the exhaust fan based on detected indoor carbon dioxide level and outdoor fine dust level; and performing a first indoor pressure control of detecting an indoor pressure and controlling the air supply fan and the exhaust fan. In the indoor pressure control, based on the detected indoor pressure being less than a first set value, a number of revolutions per minute of the exhaust fan is controlled to be decreased, and based on the detected indoor pressure is greater than or equal to a second set value greater than the first set value, the number of revolutions per minute of the exhaust fan is controlled to be increased.

A heat exchanger for heat exchange between at least two fluids includes a plurality of heat exchange elements each having at least one fluid-guiding path for conducting at least one of the fluids through. The heat exchanger has a cylindrical shape or substantially cylindrical shape with a cylinder axis around which the heat exchange elements are adjacently arranged. At lease a region of each of the heat exchange elements forms an outline structure at least substantially like one of a triangular cylinder, a trapezoidal cylinder, a circle-sector cylinder, and an annulus-sector cylinder. As a result of adjacent arrangement of the heat exchange elements, the heat exchanger or at least a region of the heat exchanger has an outline structure at least substantially like one of a polygonal cylinder, a polygonal hollow cylinder, a circular cylinder, and annular cylinder. The cylindrical shape of the heat exchanger may alternatively be a cone frustum. The heat exchanger may be incorporated into an air device.

Disclosed is a system and method for control of in-door ventilation in a building having a series of rooms separated by walls. The system includes: at least one air treatment device arranged to treat the air; a plurality of fan units, including a fan and at least one sensor; and a central computing device adapted to collect data from the sensors and control the fans. Each wall is provided with an opening, the fan units are disposed in the openings to provide an air flow transporting air from the first room through the series of rooms to the last room and then back to the first room, and the air treatment device is disposed to treat the air.

Disclosed is a system and method for control of in-door ventilation in a building having a series of rooms separated by walls. The system includes: at least one air treatment device arranged to treat the air; a plurality of fan units, including a fan and at least one sensor; and a central computing device adapted to collect data from the sensors and control the fans. Each wall is provided with an opening, the fan units are disposed in the openings to provide an air flow transporting air from the first room through the series of rooms to the last room and then back to the first room, and the air treatment device is disposed to treat the air.

An exhaust fan includes a generally square housing, adjustable-height supports, and attachments for a variety of air ducts. The air ducts are each designed to provide a sufficient air seal to effectively enable the exhaust fan to evacuate dust and debris from a wide variety of standard doors or windows, either on the ground floor or an elevated floor.

An exhaust fan includes a generally square housing, adjustable-height supports, and attachments for a variety of air ducts. The air ducts are each designed to provide a sufficient air seal to effectively enable the exhaust fan to evacuate dust and debris from a wide variety of standard doors or windows, either on the ground floor or an elevated floor.

A discharge unit includes a discharge electrode, a counter electrode opposed to the discharge electrode, and an insulation member having a surface. The surface is continuous from the discharge electrode to the counter electrode. A wall portion is provided on one side with respect to a discharge region formed by the discharge electrode. The wall portion is configured to suppress a contaminant from adhering to the surface of the insulation member.

A discharge unit includes a discharge electrode, a counter electrode opposed to the discharge electrode, and an insulation member having a surface. The surface is continuous from the discharge electrode to the counter electrode. A wall portion is provided on one side with respect to a discharge region formed by the discharge electrode. The wall portion is configured to suppress a contaminant from adhering to the surface of the insulation member.

A Heat Exchanger Unit comprising a venting unit, a shutter, a counter flow heat exchanger and a plurality of plenums. The venting unit pulls the fresh air from outdoor air through the shutter while it pushes the contaminated inside air through the counter flow heat exchanger and the plurality of plenums toward outside air.

The invention concerns predominantly enclosed spaces, typically buildings, which are exposed to directionally and temporally varying levels of solar electromagnetic radiation, as well as temporally varying levels of ambient air temperature, flow velocity and direction. Such a building can include at least one primary compartment and at least one secondary compartment. The primary compartment predominantly serves to achieve the primary purpose of the building. An electronic controller can modulate air flow to and from the secondary compartment.