Abstract: The present invention relates to a water heater system comprising: a hot water boiler having top, bottom and side walls; a flue connected to the top wall; a burner secured to a side wall of the first housing; a combustible feeder connected to the burner; an evaporator having a housing, the housing comprising an outlet, heat exchange elements located in the housing and a water discharge device spaced above the heat exchange elements, wherein the evaporator provides a source of humid air to the burner for increasing the combustion product dew point and to reduce NOx emission when burned; and a heat recovery system connected to the flue wherein the heat is used for heating water used by the water discharge device.

Abstract: A gas-fired direct-contact water heater system 10 is described. It consists of a first housing 11, 50, 80 having a packing 16, 51, 81 of heat exchange elements 17 and on which water is sprayed. A burner 18, 52, 83 is disposed on the side of the housing under the packing. A combustible gas feed pipe is connected to the burner 18, 52, 83 to provide a combustible gas to the burner. A water collection reservoir 20, 58, 86 is defined below the burner for collecting heated water. A further packing 31-59-91 having heat exchange elements is located in a further housing 30-60-90 and it is also sprayed water. Ambient air is admitted under this packing by a blower 32-63-101 whereby the air is humidified and heated and supplied to the burner for admixture with the gas whereby to obtain a higher combustion product dew point and a reduction in the NO.sub.x emission when burned.

Abstract: An air heating and humidifying system and method using direct contact heating principles. The system consists in providing a source of hot water by feeding hot flue gases in a direct contact water heater and wherein the water sprayed over a packing in the water heater is heated as it percolates through the packing and is in contact with the hot rising flue gases. This hot water from the direct contact water heater is used in a direct contact air treating chamber wherein it is sprayed over a further packing whereby to heat and humidify fresh air which is pushed through the packing by a fan and exits at an outlet flue of the treating chamber to supply hot moist fresh air in a building air conditioning system. The cooled water in the direct contact air treating chamber is collected and supplies the spray nozzle of the direct contact water heater to cool the hot flue gases which are rising therein and thereby enhances considerably the efficiency of the direct contact water heater.

Abstract: A dual direct contact water heater is described and consists of a heater housing having two sections, each section having a water reservoir. One section provides hot water at a high temperature and provides a source of heat exchange to heat an external source of water for commercial use. A burner is provided in the first section to provide the heat source to a packing through which water percolates. The source of water for the first section is the outlet of a heat exchanger whereby water from the reservoir is recirculated in a closed circuit in the first section. Hot gases rising from the first section is directed to a second section which also includes a second packing and a reservoir and it also has a closed loop whereby a second source of hot water, at a lower temperature, is utilized in a closed loop and in heat exchange with a second external source to produce domestic hot water or without heat exchanger to produce hot water for various processes.

Abstract: A gas-fired water heater is comprised of a vertical housing (11) having a circumferential side wall (12), a closed bottom end (13), and a flue (14) connected to a top end portion (15) thereof. A packing (17) of heat exchange elements (18) is supported inside the housing (11) in an uppermost region (19) thereof. A water discharge orifice or nozzle (21) is disposed above the packing (17) and connected to a water supply (22) for releasing water to be heated on the packing. An axial burner (23) is disposed substantially centrally with the housing under the packing (17). A feed pipe (24) is connected to the burner (23) and extends at least partly axially within the housing. A gas-air mixture is fed to the burner (23) through the feed pipe (24). An ignitor device (25) is provided to ignite the burner (23).

Abstract: A direct contact water heater having a hybrid heat source, and its method of operation is described. The water heater is comprised of an elongated vertical tubular housing having a water spray nozzle in an upper end thereof for spraying water substantially uniformly over a top packing of heat exchange bodies. An intermediate space is provided below the packing where external hot recovery gases are admitted into the housing. A burner chamber is provided at the bottom of the housing above a reservoir to provide a primary heat source. Heat from the primary heat source mixes with the hot recovery gases below the packing, and is in counter-current flow with the water percolating through the housing from the packing located at the top of the housing. Two packings of heat exchange bodies may be provided in the tubular housing spaced from one another with the hot recovery gases fed between the two packings and the primary hot gas from the heat source being generated below a lower one of the packings.