A vehicle heater includes a heater housing (12), through which heating air to be heated can flow, with a heating air inlet area and with a heating air outlet area. A burner unit is arranged in the heater housing. A combustion air blower is arranged in the heater housing for feeding combustion air to the burner unit. A heat exchanger unit is arranged in the heater housing (12). Heating air flowing through the heater housing (12) can flow around the heat exchanger unit. A combustion air intake muffler (76), which is essentially arranged in the heater housing (12), is associated with the combustion air blower (46).

A vehicle heater includes a housing (10) with a circumferential wall (12), defining a combustion air flow space (14), having a fuel line passage opening (30), a combustion chamber assembly unit, and a fuel line (28). The fuel line has a connection end area (54) adjoining the combustion chamber assembly unit (18), an external connection end area (58), outside the circumferential wall and a line area (56) between the end areas and passing through the fuel line passage opening. A sealing formation (32) has a first sealing area (34), meshing with the fuel line passage opening, and a passage opening (52) through which the line area of the fuel line passes. The fuel line has a larger cross-sectional dimension in a throughput length area (60), passing through the passage opening, than in a section of the line area located between the throughput length area and the external connection area.

A vehicle heater housing (46) has an inlet area (49), an outlet area (51) and an air flow space (47) for air to be heated with a burner chamber assembly unit (30), to be fed with combustion air and fuel. A heat exchanger area (11), including a heat exchanger housing (12), is elongated in the direction of a housing longitudinal axis (L) with an outer side (24) around which air flowing in the air flow space flows. Heat transfer ribs are on a side of the heat exchanger housing. The heater housing has a housing circumferential wall (56) and an outlet front wall area (58). The heat transfer ribs have a longitudinal edge (64) extending along the housing circumferential wall and a radial edge extending along the outlet front wall area. A distance of the radial edge from the outlet front wall area changes from radially outwards to radially inwards.

A process for manufacturing a cast metal heat exchanger housing (12) for a vehicle heater having a pot-shape housing wall (14) extending in a direction of a housing longitudinal axis (L) and having a plurality of heat transfer ribs (22) extending on an outer side of the housing wall (14) in the area of a circumferential wall (16) and in the area of a bottom wall (18) of the housing wall (14) in the direction of the housing longitudinal axis (L). The process includes metal casting wherein a sprue cross-sectional area including at least some of the heat transfer ribs (22). The cast metal heat exchanger housing has an axial end face formed upon cutting off metallic material that is essentially at right angles to the housing longitudinal axis and extends into an area of at least some of the heat transfer ribs.

The invention relates to a portable heating system that in a first instance provides heat and in a second instance provides a source of electrical current from thermo electric modules where the produced electrical energy is intended to be forwarded to a rechargeable battery. The rechargeable battery serves as a current source for the portable heating system e.g. for driving the fuel pump and air fans. When the rechargeable battery is replenished with electrical energy a control is configured to switch the by the thermo electrical modules generated electrical energy to selected power consumers arranged with the portable heating system in order to facilitate the thermo electrical modules to keep the intended quality serving as a heat pump for transferring the produced heat from a burner to a transportation media for releasing the heat in the designated intended area.

A thermally enhanced heating system and a method for thermally enhancing a HVAC system are provided. The thermally enhanced heating system preferably includes an outdoor HVAC unit and an indoor HVAC unit. The indoor HVAC unit includes a first heat exchanger for transferring heat from a refrigerant, a second heat exchanger for transferring heat from a fuel source, and a third heat exchanger for transferring heat to the refrigerant. The outdoor HVAC unit includes an outdoor heat exchanger for transferring heat from an outdoor air to the refrigerant, a pump configured to circulate the refrigerant, and an ejector configured to combine the refrigerant from the outdoor heat exchanger and the third heat exchanger. Preferably the outdoor HVAC unit is operated to circulate the refrigerant through a first refrigerant circuit and a second refrigerant circuit, and combine refrigerant in the first refrigerant circuit and the second refrigerant circuit.

A heat recovery system includes a compressor, a solar panel, and a first heat exchanger and a second heat exchanger in fluid connection to form a closed circuit. The compressor is configured to facilitate fluid movement in the fluid circuit between the solar panel, the first heat exchanger and the second heat exchanger. The solar panel includes a plurality of solar cells connected in parallel, and each solar cell includes a plurality of metal tubes for fluid to pass through. A temperature sensor is mounted within each of the solar cells and configured to measure temperature inside the respective solar cell. Each solar cell is connected to the circuit via a respective pressure valve, and the status of the pressure valve is configured to depend on the measurement of the temperature sensor in the respective solar cell.

Provided herein are embodiments of, a multistage gas furnace, a controller therefor and a computer-usable medium having non-transitory computer readable instructions stored thereon for execution by a processor to perform a method for operating a gas furnace. In one embodiment, the gas furnace includes: (1) a burner, (2) a circulation fan and (3) a furnace controller. The furnace controller having: (3A) an interface configured to receive heating calls and a blower control signal, the blower control signal corresponding to an operating speed of the circulation fan and (3B) a processor configured to respond to the heating calls and the blower control signal by setting and adjusting a gas input rate for the burner that is based on the blower control signal and that corresponds to a discharge air temperature determined by a dedicated discharge air sensor associated with the furnace.

Provided is an RPM control method for an inducer for a gas furnace that induces a flow of combustion gas produced in a burner from a heat exchanger to an exhaust pipe. The RPM control method for an inducer for a gas furnace includes: (a) initiating a heating operation for the gas furnace; (b) determining whether the operation time during which the heating operation is performed is equal to or longer than a first time period; (c) if it is determined that the operation time is equal to or longer than the first time period, detecting whether a pressure switch is turned OFF; and (d) if the pressure switch is detected as turned OFF, increasing the RPM of the inducer by a first value.

An indirect gas-fired condensing furnace assembly and method includes a primary heat exchanger, a secondary heat exchanger, and a tertiary heat exchanger. The secondary heat exchanger assembly may be an intermediate single-pass tubular heat exchange section made from a corrosion-resistant material. The tertiary heat exchanger assembly may be a single-pass tubular heat exchanger section with a corrosion resistant material. The tertiary heat exchanger assembly may include a plurality of fins. The primary heat exchanger assembly may include a plurality of aligned tubes wherein each tube includes a first straight portion, an intermediate portion, and a second straight portion such that the primary heat exchanger tubes surround the secondary and the tertiary heat exchanger assemblies such that the airflow is configured to traverse the primary heat exchanger assembly, the secondary heat exchanger assembly, and the tertiary heat exchanger assembly in various directions such that a risk of condensation freezing within the secondary and tertiary heat exchange assemblies is reduced.