A heating and hot water supply system, including: a combustion unit combusting a fuel to generate a combustion gas; a heat exchange unit heating a heat medium and hot water according to heat exchange with the combustion gas; an exhaust unit that exhausting the combustion gas after heat exchange. The heat exchange unit includes a plate type heat exchanger by laminating vertically-upright rectangular plates with gaps, and is configured to heat the heat medium by causing the combustion gas and the heat medium to alternately flow through the gaps. An inlet for the heat medium is provided at lower corner of the plate type heat exchanger, a discharge opening for the heat medium is provided at upper corner farthest from the inlet, and a hot water passage through which hot water flows in the plate type heat exchanger is provided at upper corner above the inlet.

A heat exchanger for a boiler or similar heating device comprises a casing and a tube assembly inside the casing. The tube assembly includes a plurality of modules (6.sub.x, 6.sub.y) arranged in a juxtaposed configuration, each module (6.sub.x, 6.sub.y) having an at least approximately annular shape. The modules (6.sub.x,6.sub.y) each include a respective tube (7) that is at least partially embedded in a respective thermally conductive body (8) overmoulded to the tube (7). Each thermally conductive body (8) defines an upper face and a lower face of the respective module (6.sub.x, 6.sub.y), where at least at the upper face of a first module (6.sub.y) and the lower face of a second module (6.sub.x) the corresponding thermally conductive body (8) defines upper fins (24) and lower fins (23.sub.x), respectively, which extend in height substantially in an axial direction of the tube assembly and extend in length substantially in a radial direction of the tube assembly (5). The upper fins (24) of the thermally conductive body (8) of the first module (6.sub.y) are in an axially staggered position with respect to the lower fins (23.sub.x) of the thermally conductive body (8) of the second module (6.sub.x), with the upper fins (24), on the one hand, and with the lower fins (23.sub.x), on the other hand, which are at mutual distances such that the upper fins (24) of the thermally conductive body (8) of the first module (6.sub.y) are set between the lower fins (23.sub.x) of the thermally conductive body (8) of the second module (6.sub.x), or vice versa. In this way, between each upper fin (24) of the thermally conductive body (8) of the first module (6.sub.y) and each lower fin (23.sub.x) of the thermally conductive body (8) of the second module (6.sup.x), or vice versa, a respective radial passageway (P) is defined for the combustion fumes produced by a burner equipping the heat exchanger.

A burner box assembly according to aspects of the disclosure includes an outer cover, the outer cover having a sloped bottom face that directs condensation away from a heat-exchange tube, a heat-resistant liner having a plurality of panel members, the heat-resistant liner being disposed within the outer cover, a shield disposed between the heat-resistant liner and the sloped bottom face of the outer cover such that an air gap is formed between the shield and the sloped bottom face, and a tubular member abutting at least one of the plurality of panel members and disposed within the heat-exchange tube.

According to various aspects, exemplary embodiments are disclosed of blow through direct fired heaters including evaporator coils and/or energy recovery ventilation.

A gas furnace is provided. The gas furnace includes a combustion part in which a fuel gas is burnt to generate a combustion gas, a heat exchanger having a gas flow path through which the combustion gas flows, a blower configured to blow air around the heat exchanger, and an inducer configured to discharge the combustion gas from the heat exchanger. The heat exchanger includes at least one single path in which a single gas flow path is formed a single-multiple return bend configured to communicate with the single path and convert a flow direction of the combustion gas, and at least one multiple path having a plurality of paths that communicate with the single-multiple return bend and form multiple gas flow paths.

A furnace for a heating, ventilation, and air conditioning (HVAC) unit includes a heat exchange tube configured to flow combustion products therethrough and place the combustion products in a heat exchange relationship with an air flow directed across the heat exchange tube. The furnace also includes a burner assembly fluidly coupled to a first port of the heat exchange tube and configured to generate the combustion products directed into the heat exchange tube via the first port, and a draft inducer blower fluidly coupled to a second port of the heat exchange tube and configured to draw the combustion products through the heat exchange tube. The burner assembly is higher in position than the draft inducer blower relative to a base of the HVAC unit.

A radiant tube includes a conduit; and one or more heat transfer promoters disposed in the conduit, wherein the heat transfer promoter includes a body part on a center side of the conduit, and protruding parts protruding from the body part toward an inner wall surface of the conduit, the protruding parts are on an outer periphery of the body part to be arranged in a circumferential direction of the conduit, the protruding parts includes first protruding parts having a distal end portion facing the inner wall surface across a gap ΔL, and a second protruding part, the number of first protruding parts is greater than the number of second protruding parts, and a ratio (ΔL/Dt) of the gap ΔL to an equivalent diameter Dt of a conduit portion is x %, where the heat transfer promoter is disposed, and formula (1) is satisfied: 0.3%<x<7%.

Disclosed are a gas furnace and an air conditioner having the same. The gas furnace includes: a burner for burning fuel; a heat exchanger extending long and providing a passage for combustion gas generated by the burner; a blower for causing a flow of air passing around the heat exchanger; and a plurality of guides passing through the heat exchanger and spaced apart from each other in a longitudinal direction of the heat exchanger. The heat exchanger includes: a first tube forming an entry of the heat exchanger; a second tube forming an exit of the heat exchanger and spaced apart from the first tube in a direction crossing the longitudinal direction of the heat exchanger; and a bend connecting the first tube and the second tube. The plurality of guides is alternately disposed in a direction in which the first tube and the second tube are spaced apart from each other.

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.

A heat exchanger with a tube bundle wound in a helical manner about a longitudinal axis. The tube bundle includes at least two tube sections which are placed beside each other in the direction of the longitudinal axis. The tube sections each include a helically wound tube with has an internal cross-section which is constant over the helical winding thereof.