A double pipe for a heat exchanger includes an inner pipe disposed in an outer pipe. In a straight-pipe portion of the double pipe, the inner pipe has a plurality of protruding parts extending in a helically offset manner along a longitudinal direction, an inner-circumferential surface of the outer pipe directly contacts the protruding parts, and outer-side channels are partitioned at a plurality of locations in a circumferential direction of the double pipe. The protruding parts are curved to protrude radially outward. In a cross section of the straight-pipe portion orthogonal to the longitudinal direction, the inner-circumferential surface of the outer pipe is circular, and an average value of D/L values of all the outer-side channels is 0.09-0.20, wherein D is defined as a maximum depth of each of the outer-side channels and L is defined as an arc length of each of the outer-side channels in the circumferential direction.

The present disclosure provides a heat exchanger flat tube and a heat exchanger with the heat exchanger flat tube, the heat exchanger flat tube includes two plates opposite to each other, a fluid passage is formed between the two plates, a turbulence structure is provided in the fluid passage and has a gradually expanding portion and a gradually narrowing portion, both an extension direction of the gradually expanding portion and an extension direction of the gradually narrowing portion are consistent with a flow direction of a fluid, and the gradually narrowing portion is located downstream of the gradually expanding portion along the flow direction of the fluid.

A heat exchange apparatus, and more particularly a condenser device, is provided. The condenser includes a housing with tubes that have grooves on the outer surface thereof, baffles, and inlet and outlet manifolds for tube-side and shell-side heat transfer fluids. An outside of each of the tubes is coated with a material having a low wetting coefficient. The baffles of the condenser are formed so, and the that the distance between the baffles decreases from the shell-side heat transfer fluid inlet manifold to the shell-side heat transfer fluid outlet manifold. The inner surfaces of the tubes have protuberances thereon and are coated with a material having a high adhesion resistance coefficient.

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 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.

An integrated exhaust system apparatus to be mounted on an engine is provided. The apparatus includes an apparatus housing; an engine interface; an exhaust system interface with a first exhaust apparatus outlet configured to direct a first portion of exhaust through the housing wall; an EGR interface with a second exhaust apparatus outlet configured to direct a second portion of exhaust through the apparatus housing wall; and an exhaust manifold arranged within the apparatus interior. The exhaust manifold includes a first manifold outlet configured to direct the first portion of exhaust out of the manifold interior and a second manifold outlet configured to direct the second portion of exhaust out of the manifold interior. An EGR cooler is arranged within the apparatus interior with passages fluidly coupled such that the second portion of exhaust is directed out of the apparatus housing via the second exhaust apparatus outlet.

A heat transfer system includes a steam chamber that communicates in an open-loop arrangement with a first steam source for supplying steam to the steam chamber, the steam chamber including a steam exit for supplying steam to air at atmospheric pressure. A heat transfer tube communicates in a closed-loop arrangement with a second steam source for supplying steam to an interior surface of the heat transfer tube, the heat transfer tube vaporizing condensate forming within the heat transfer system back to steam that is supplied to the air via the steam exit. The outer surface of the heat transfer tube is configured to contact the condensate and vaporize the condensate back into steam, wherein the heat transfer tube includes a plurality of pockets formed on the outer surface of the tube, each pocket including a pocket exit/entry portion having a smaller cross-sectional area than the cross-sectional area of the pocket at a root portion thereof adjacent the outer surface of the tube.

A heat exchange device and a freeze dryer. The freeze dryer comprises a bearing device, and an evaporation device and a condensation device which are provided on the bearing device, at least one of the evaporation device and the condensation device comprising a structure of the heat exchange device. The heat exchange device is integrally molded by extrusion, and the heat exchange device is provided with at least one medium flow passage, a plurality of fins are formed on the outer periphery of the medium flow passage, and the fins being provided at intervals to form gaps allowing airflows to pass therethrough. The heat exchange device and the freeze dryer of the present disclosure can be designed to be smaller, reducing the volume, and facilitating miniaturization of products.

A heat exchanger and an antenna assembly having the same are described herein that enable a compact antenna design with good thermal management. In one example, a heat exchanger is provided that includes tube-shaped body. A main cooling volume is formed between the top and bottom surfaces proximate to the outside wall. The main cooling volume has an inlet formed through the top surface and an outlet formed through the bottom surface. A return volume is formed adjacent the inside diameter wall and is circumscribed by the main cooling volume. The return volume has an outlet formed through the top surface and an inlet formed through the bottom surface. One or more exterior fins are coupled to an exterior side of the outside wall. A plurality of fins extend into the main cooling volume. A plurality of inner fins extend into a passage from the inside diameter wall.

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.