A water heater includes a burner of a premixed type, a heat exchanger, and a fan suctioning combustion gas and exhausting combustion gas to the outside. The burner includes a burner case partitioned into a combustion chamber and a gas introduction chamber by a partition plate and a plurality of combustion tubes arranged in the combustion chamber. An air supply opening for supplying air into the gas introduction chamber is provided in the burner case. The partition plate has a plurality of opening portions communicating with the inside of the combustion tubes and a plurality of through holes communicating with the outside of the combustion tubes within the combustion chamber. The air supply opening is constructed to have an opening area smaller than the total sum of the total of opening areas of the plurality of opening portions and the total of opening areas of the plurality of through holes.

A process air unit (20) for heating a process air (21) for a workpiece processing system comprises a process air duct (22) through which a process air (21) can flow, a combustion chamber (30) for burning a combustion air, which is overflowed by the process air (21) in the process air duct (22) and thereby transfers heat to the process air (21), and a tube bundle arrangement (35) connected to the combustion chamber, which comprises at least one tube bundle (36) having a plurality of tubes (38) through which the flue gas (34) from the combustion chamber (30) can flow. The plurality of tubes (38) of the at least one tube bundle (36) is oriented in the process air duct (22) transversely to the process air flow direction, so that they are overflowed by the process air (21) and thereby transfer heat from the flue gas (34) to the process air (21), and the tube bundle arrangement (35) is arranged, with respect to the process air flow direction, upstream of the combustion chamber (30) in the process air duct (22) in order to achieve increased energy efficiency.

A heating, ventilating, and air conditioning (HVAC) system includes a furnace having a primary heat exchanger and a secondary heat exchanger, where the primary heat exchanger and the secondary heat exchanger form a heat exchange relationship between an airflow and an exhaust gas, and where the primary heat exchanger is positioned upstream of the secondary heat exchanger, a burner configured to generate the exhaust gas, a sensor configured to monitor an ambient temperature, and a control system configured to receive feedback from the sensor, compare the feedback to a threshold, operate the furnace in a first mode when the ambient temperature exceeds the threshold, and operate the furnace in a second mode when the ambient temperature is at or below the threshold, where the furnace operates above a condensation temperature when in the second mode, such that the exhaust gas does not condense when operating in the second mode.

A heat exchanger includes a lamellar structure of a plurality of parallel heat exchange elements with an intermediate air gap between each pair of adjacent heat exchange elements. Along a longitudinal direction of the lamellar structure the heat exchange elements is interconnected in a top portion of the lamellar structure that forms an inlet channel through the heat exchange elements and in a bottom portion of the lamellar structure that forms an outlet channel through the heat exchange elements.

The heat exchange elements form parallel channels between the inlet and the outlet channels.

In the outlet channel, the heat exchanger includes a filler body, that is filling up a lower level of the outlet channel and forms a floor along the longitudinal direction of the lamellar structure.

Embodiments of the invention provide a heater including a housing, a first tankless heater, a second tankless heater, a first and second flow directing elements, the first flow directing element in communication with the first tankless heater and the second flow directing element and the second flow directing element in communication with the second tankless heater, and a controller in communication with the first and second tankless heaters and the first and second flow directing elements, the controller configured to control the first and second flow directing elements to control flow to one or both of the first and second tankless heaters.

Processes and apparatuses for heating a process fluid. The process fluid flow through a convection section and then a radiant section. The radiant section produces heat and flue gas from the combustion of the fuel. The flue gases flow to the convection section to provide the heat in the convection section. The conduits in the convection section are straight. All of the fluid that passes through the convection section also passes through the radiant section.

It is common in heating systems, such as in a hot water heater for there to be a combustor with the exhaust gases from the combustor provided to a heat exchanger to heat up the water. Disclosed herein is an integrated heat exchanger and burner assembly in which the combustion occurs proximate the surface of the heat exchanger. Such a system may include at least one tube that is coiled into a number of turns, that is a tube coil with the at least one tube having an inlet and an outlet and the distance between adjacent turns is less than a predetermined distance, i.e. a the quench distance.

The present invention concerns a boiler, in particular a condensing boiler, said boiler comprising at least one combustion zone, and a burner arranged in correspondence with said combustion zone along a longitudinal axis, and at least one first heat exchanger adapted to encircle said burner with its internal portion facing towards said burner and directly exposed to the flame of said burner, when in use, said heat exchanger providing a steel duct, preferably stainless steel, having a spiral profile and comprising a plurality of coils having a common axis of symmetry, the axis of symmetry of said first heat exchanger coinciding with said longitudinal axis of the boiler, said boiler being characterised in that the internal portion facing towards said axis of symmetry of each coil of said first heat exchanger has a continuous depression along at least one portion of said spiral profile.

A premixing device includes: a main pipe of a cylindrical shape, which is disposed so as to surround an air passage and has a fuel chamber of an annular shape, which is formed inside a pipe wall; a butterfly valve having an air inlet hole and rotatably disposed so as to be located within the air passage; at least one support part which internally has a fuel passage communicating with the fuel chamber and extends radially inward from an inner wall surface of the main pipe so as to be located within the air passage downstream of the butterfly valve; and a venturi ring supported by the at least one support part so as to be located within the air passage downstream of the butterfly valve. The fuel passage has an outlet opening into a space of the air passage on an inner circumferential side of the venturi ring.

Disclosed are a gas furnace and an air conditioner having the same. The gas furnace includes: a burner for burning fuel; a manifold providing the fuel to an entry of the burner; a heat exchanger spaced apart from an exit of the burner and providing a passage for combustion gas generated by the burner; an inducer for causing a fluid to flow through the burner and the heat exchanger; a blower for causing a flow of air passing around the heat exchanger; and an air shutter positioned between the manifold and the entry of the burner. The air shutter includes: a housing having an inner space that communicates with the manifold and the entry of the burner; and a primary hole formed to penetrate the housing and able to be opened and closed.