A tube sheet for a thermal transfer device can include a body having a plurality of apertures that traverse therethrough, where the plurality of apertures are configured to receive a plurality of tubes of the thermal transfer device. The tube sheet can also include an outer perimeter defining the body, where the outer perimeter has at least one first recess feature disposed therein. The at least one first recess feature can have a first shape and a first size, where the first shape is any shape aside from a semi-circle.

A high efficiency downfired gas water heater is provided which has a tank for storing water to be heated, a combustion chamber extending downwardly through a top end of the tank, and a gas burner operative to create hot combustion products within the combustion chamber. At the bottom end of the tank is a transfer chamber coupled to an external discharge conduit and to a single pass heat exchanger, in the form of multiple flue tubes. extending vertically through the tank and connected to the combustion chamber. In one embodiment of the water heater the burner is a power burner which forces the combustion products sequentially through the combustion chamber, heat exchanger, transfer chamber and discharge conduit. In another embodiment of the water heater a draft inducer fan is used to draw the combustion products through this path from the combustion chamber.

The purpose of the present invention is to provide a tube assembly for a tubular heat exchanger and a tubular heat exchanger comprising the same, the tube assembly for a tubular heat exchanger being capable of enhancing efficiency in heat exchange between a heat medium and a combustion gas and also preventing high-temperature oxidation and the burn-out of a turbulator caused by the combustion heat of the combustion gas and preventing the deformation or damage of a tube which may occur in an environment with a high water pressure, thereby improving the durability thereof. The tube assembly for a tubular heat exchanger of the present invention, for achieving the purpose, comprises: a tube which is formed in a flat shape and enables a combustion gas generated in a combustion chamber to flow along the inside thereof and exchange heat with a heat medium which flows outside thereof; and a turbulator which is coupled to the inside of the tube and induces the generation of turbulence in the flow of the combustion gas.

A boiler system having a generally cylindrical housing or shell includes a main or fire tube with a furnace or combustion chamber extending longitudinally near the bottom of the housing and a burner to accomplish combustion within the combustion chamber. The combustion chamber opens at its rear end to furnace tube sheet, and to a first set of tubes extending longitudinally of the boiler. The first set of tubes extends to and through the rear tube sheet of the boiler to a turnaround space, which transitions to a second set of tubes located above the combustion chamber and first set of tubes to generally span a length extending from the rear tube sheet of the boiler to the front tube sheet. The boiler system as disclosed has a reduced size while maintaining efficiency in steam and hot water applications.

The objective of the present invention is to provide a tubular heat exchanger capable of improving heat exchange efficiency and preventing deformation and damage thereof even in a high water-pressure environment. To this end, the present invention includes an outer jacket through which a heat medium is introduced and discharged; a combustion chamber coupled to the inside of the outer jacket so that a heat medium passage is formed between the combustion chamber and the outer jacket, and configured to perform combustion of a burner; a plurality of tubes formed in a flat shape for allowing combustion gas, which is generated in the combustion chamber, to flow along the inside of the combustion chamber and exchange heat with the heat medium; and a turbulator coupled to the inside of the tubes so as to induce generation of turbulence in a flow of the combustion gas.

A modulating burner apparatus includes a variable speed blower feeding a multi-chamber burner having first and second burner chambers. A manifold system communicates the blower with the burner, and a flow control valve member is located between the blower and the second chamber of the burner. The flow control valve is configured to provide fuel and air mixture from the blower to only the first burner chamber at lower blower speeds of the blower and to both the first and second burner chambers at higher blower speeds of the blower.

A water heater system includes a primary heat exchanger including a tank and at least one flue, and a secondary heat exchanger including a core and a flue gas flow path. The water heater is operable in a heating mode in which a combustor produces hot flue gas and a water pump flows water through the core of the secondary heat exchanger and into the tank, and in a non-heating mode in which the combustor and the water pump are inoperative. The flue gas flows from the combustor through the at least one flue to heat the water in the tank and then through the flue gas flow path to heat water in the core before being exhausted.

A heating device has a combustion chamber and a gas flue configured to guide hot exhaust gas generated in the combustion chamber, the flue having an inlet region and an outlet region and is configured connected to the combustion chamber via the inlet region. Heat transfer ribs having a wall thickness are arranged spaced from each other in the gas flue for the heat transfer from hot exhaust gas to the gas flue. The wall thickness of the heat transfer ribs and/or the distances of the heat transfer ribs to one another are optionally configured to be larger on the sides of the inlet region than on the sides of the outlet region.

A tube for a thermal transfer device can include at least one wall having an inner surface and an outer surface, where the inner surface forms a cavity. The inner surface can be non-cylindrical. The cavity can be configured to receive a fluid that flows continuously along a length of the at least one wall.

An apparatus includes an evaporator-expansion module configured to (A) provide electric energy to a building structure, and (B) cooperate with an air-handler module configured to provide thermal energy to a building structure. The evaporator-expansion module includes an evaporator assembly including a heated fluid conduit, a refrigerant conduit, and a thermal buffer. The heated fluid conduit is configured to convey a heated fluid. The refrigerant conduit is configured to convey an evaporator refrigerant. The thermal buffer is configured to be positioned relative to the heated fluid conduit and the refrigerant conduit. This is done in such a way that the thermal buffer transfers thermal energy from the heated fluid that is positioned in the heated fluid conduit to the evaporator refrigerant that is positioned in the refrigerant conduit.