Embodiments of the subject invention are directed to methods and apparatus for inducing mixing in a fluid using one or more plasma actuators. In an embodiment, a pair of electrodes is positioned near a fluid and a voltage potential is applied across the pair of electrodes such that a plasma discharge is produced in the fluid. In an embodiment, the plasma discharge creates turbulence in the fluid thereby mixing the fluid. In an embodiment, flow structures, such as vortices are generated in the fluid. In an embodiment, the fluid is mixed in three dimensions. In an embodiment, a plurality of fluids are mixed. In an embodiment, solids are dispersed in at least one fluid. In an embodiment, heat or other properties are dispersed within at least one fluid. In an embodiment, at least one of the pair of electrodes has a serpentine shape.

Embodiments of the subject invention are directed to methods and apparatus for inducing mixing in a fluid using one or more plasma actuators. In an embodiment, a pair of electrodes is positioned near a fluid and a voltage potential is applied across the pair of electrodes such that a plasma discharge is produced in the fluid. In an embodiment, the plasma discharge creates turbulence in the fluid thereby mixing the fluid. In an embodiment, flow structures, such as vortices are generated in the fluid. In an embodiment, the fluid is mixed in three dimensions. In an embodiment, a plurality of fluids are mixed. In an embodiment, solids are dispersed in at least one fluid. In an embodiment, heat or other properties are dispersed within at least one fluid. In an embodiment, at least one of the pair of electrodes has a serpentine shape.

A filter assembly structure and a water heater including the same are provided. The filter assembly structure includes a filter housing coupled to an inner surface of a base panel provided in a case of a water heater, and including a flow space formed together with the inner surface of the base panel and an entrance to communicate with the flow space, and a filter assembly detachably assembled with the filter housing and including an air filter to filter air introduced through an air inlet provided in the base panel. The filter assembly is provided in a slide structure and inserted into or separated from the filter housing through the entrance.

A combustion system includes a premix blower system and the premix blower system includes an additional air inlet with an adjustable opening which includes an additional reversibly pluggable air intake. The adjustable opening of the additional air inlet can be opened at higher elevations to compensate for thinner air.

The invention is directed to a method for reducing NOx emission from an industrial process furnace comprising a firebox containing a burner and a tube, which method comprises subjecting an oxidant gas and/or a fuel gas (1) to humidification, thereby obtaining a humidified gas; and pre-heating the humidified gas with an external waste heat stream (20) before feeding the gas to the burner.

The invention is directed to a method for reducing NOx emission from an industrial process furnace comprising a firebox containing a burner and a tube, which method comprises subjecting an oxidant gas and/or a fuel gas (1) to humidification, thereby obtaining a humidified gas; and pre-heating the humidified gas with an external waste heat stream (20) before feeding the gas to the burner.

A fresh-air intake according to aspects of the disclosure includes an outer cover having a pair of side panels disposed in a generally parallel spaced relationship, a top panel coupled to, and disposed generally perpendicular to, each panel of the pair of side panels, a bottom panel disposed generally parallel to the top panel, and a front panel coupled to, and disposed generally perpendicular to, each panel of the pair of side panels and the top panel, the front panel having a window formed therein, a supply line coupled to the bottom panel, a weir extending above the bottom panel and surrounding a junction with the supply line, a baffle disposed inside the outer cover, the baffle being disposed inwardly of the window so as to prevent infiltration of moisture into the supply line, and a weep hole formed in the bottom panel.

A fresh-air intake according to aspects of the disclosure includes an outer cover having a pair of side panels disposed in a generally parallel spaced relationship, a top panel coupled to, and disposed generally perpendicular to, each panel of the pair of side panels, a bottom panel disposed generally parallel to the top panel, and a front panel coupled to, and disposed generally perpendicular to, each panel of the pair of side panels and the top panel, the front panel having a window formed therein, a supply line coupled to the bottom panel, a weir extending above the bottom panel and surrounding a junction with the supply line, a baffle disposed inside the outer cover, the baffle being disposed inwardly of the window so as to prevent infiltration of moisture into the supply line, and a weep hole formed in the bottom panel.

A fresh-air intake according to aspects of the disclosure includes an outer cover having a pair of side panels disposed in a generally parallel spaced relationship, a top panel coupled to, and disposed generally perpendicular to, each panel of the pair of side panels, a bottom panel disposed generally parallel to the top panel, and a front panel coupled to, and disposed generally perpendicular to, each panel of the pair of side panels and the top panel, the front panel having a window formed therein, a supply line coupled to the bottom panel, a weir extending above the bottom panel and surrounding a junction with the supply line, a baffle disposed inside the outer cover, the baffle being disposed inwardly of the window so as to prevent infiltration of moisture into the supply line, and a weep hole formed in the bottom panel.

A fresh-air intake according to aspects of the disclosure includes an outer cover having a pair of side panels disposed in a generally parallel spaced relationship, a top panel coupled to, and disposed generally perpendicular to, each panel of the pair of side panels, a bottom panel disposed generally parallel to the top panel, and a front panel coupled to, and disposed generally perpendicular to, each panel of the pair of side panels and the top panel, the front panel having a window formed therein, a supply line coupled to the bottom panel, a weir extending above the bottom panel and surrounding a junction with the supply line, a baffle disposed inside the outer cover, the baffle being disposed inwardly of the window so as to prevent infiltration of moisture into the supply line, and a weep hole formed in the bottom panel.