A heating, ventilation, and/or air conditioning (HVAC) system may include a furnace having at least one heat exchanger tube with a temperature protection sleeve at least partially disposed in the heat exchanger tube. The temperature protection sleeve includes a flange, an elongated tubular portion extending from the flange, and a plurality of perforations disposed about the elongated tubular portion. The temperature protection sleeve protects the heat exchanger tube from high flame temperatures or elevated temperature flue products caused by rapidly combusting a pre-mixed air-fuel mixture within a burner of the furnace, thereby allowing the heat exchanger tube to comply with ANSI Z21.47. The furnace provides less than 14 Nanograms of oxides of nitrogen per Joule (Ng/J) of heat delivered to a temperature conditioned area and complies with SCAQMD Rule 1111.

A heat exchanger device is disclosed herein. The heat exchanger device includes a dryer-exhaust interface configured to releasably couple with the exhaust port of the clothes dryer and to receive the hot air from a clothes dryer, a heat exchanger configured to exchange heat from the dryer's exhaust to ambient air, and an exhaust outlet that discharges heated air from the exhaust. The device is may useful for recycling hot air from a clothes dryer into a home and help with heating the home.

Disclosed is a heat exchanger that has an internal air flow pattern such as a helical pattern. The heat exchanger includes a shell that encompasses an inner series of heat exchange tubes and an outer series of heat exchange tubes. A baffle sheet is juxtaposed next to the outer series of heat exchange tubes. And the baffle sheet is configured to direct air flow within the heat exchanger in a configuration, such as a helical configuration, from a center of the shell toward an outer region of the shell.

A heat exchanger tube includes a first pass for at least partially combusting a fuel and the first pass having a modified shape including a minor diameter and major diameter that reduces the external pressure drop of an external fluid flowing across the heat exchanger tube. A HVACR system includes a heat exchanger tube with a first heat exchange pass that at least partially combusts a fuel and has a modified shape. A method of making a heat exchanger including configuring a first heat exchange pass such that the major diameter of modified portion of the first heat exchange pass is oriented towards an incoming direction of the process fluid

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.

A heating device with hot water supply function includes: a combustion means; a first heat exchanger; a circulation passage that connects the first heat exchanger and an room heating unit; a circulation pump; a bypass passage that branches off from the circulation passage; a second heat exchanger for hot water supply provided in the bypass passage; a cold water supply passage; a hot water supply passage for supply of hot water from the second heat exchanger; and a distribution means that is provided at a branching section and whose distribution ratio can be adjusted, so that it becomes possible selectively to execute either only room heating operation, or only hot water supply operation, or simultaneous room heating operation and hot water supply operation; wherein the hot water supply outlet, the thermal medium inlet, and the room heating outlet of the distribution means are at the same height.

A heat exchanger includes a burner configured to burn a combustible gas to produce heat, a heat exchanger configured to receive the heat from the burner, a flow sensor configured to measure a flow rate of a coolant passing through the heat exchanger; and a controller comprising processing circuitry. The processing circuitry receives flow data from the flow sensor and controls a firing rate of the burner based on a predetermined relationship between a differential temperature of coolant flowing through the heat exchanger and the coolant's flow rate.

A plate fin for a heat exchanger is provided including a base plate having a plurality of holes formed therein. The plate fin also includes a plurality of generally annular collars. Each collar is positioned substantially coaxially within one of the plurality of holes. The plurality of first collars is substantially less than the plurality of holes such that a portion of the plurality of holes does not have a collar arranged therein.

A pump system for use with a solar collector system which is used to heat a heat transfer fluid, includes a storage tank and the pump system having a first and second pump arranged in parallel which can pump the heat transfer fluid from the storage tank to a solar collector, so that should one pump fail the other pump can function, wherein the outlet of the first pump and the outlet of the second pump are connected to a valve arrangement, whereby when the first pump operates the outlet of the second pump is substantially closed by the flow from the first pump and when the second pump operates the outlet of the first pump is substantially closed by the flow from the second pump.

A system of capturing waste heat includes a heat recovery unit (20) having a heat exchanger (35) arranged to transfer heat between a fluid circulating in a refrigerant loop (60) and a fluid circulating in a solar loop (70) and another heat exchanger (39) arranged to transfer heat between the fluid in the solar loop (70) and a fluid circulating in a water loop (50). Controllable first, second, and third three-way valves (V1-V3) provide or prevent, depending on fluid temperatures, an A-B, B-C, and A-C flow path through the valve. The first valve (V1) is arranged in the water loop (50) upstream of the second heat exchanger (39). The second (V2) is arranged in the solar loop (70) upstream of the second heat exchanger (39). The third valve (V3) is arranged in the solar loop (70) between the first and second heat exchangers (35, 39).