In a first and second corrugated portions of a first and second heat transfer plates, first front-side convex portions that are convex toward one side in a first direction and first back-side convex portions that are convex toward the opposite side in the first direction are alternately formed along a second direction. In at least one end of both ends of each of the first front-side convex portions in the second direction, a first front-side protruding portion protruding toward another first front-side convex portion is provided. The first front-side protruding portion is contactable with the second heat transfer plate. In at least one end of both ends of each of the second front-side convex portions in the second direction, a second front-side protruding portion protruding toward another second front-side convex portion is provided. The second front-side protruding portion is contactable with the first heat transfer plate.

The disclosed technology includes systems and methods for a heat pump water heater. The disclosed technology can include a heat pump water heater system having an evaporator, a condenser, a vapor injection line, a compressor, and a multi-fluid heat exchanger. The vapor injection line can include an expansion valve to transition refrigerant received from the condenser at a first pressure to a second pressure. The compressor can be configured to circulate refrigerant through the condenser, the multi-fluid heat exchanger, the vapor injection line, and the evaporator. The multi-fluid heat exchanger can be configured to receive refrigerant at a first pressure from the condenser, refrigerant at a second pressure from the vapor injection line, and water. The multi-fluid heat exchanger can further facilitate heat transfer between the refrigerants at the first and second pressures and the water to preheat the water before the water is passed through the condenser.

A heat exchanger is configured to adjust a flow restriction of flow passages through the heat exchanger in response to changes in temperature of elements that define at least a portion of the flow passages. The elements include a first material having a first coefficient of thermal expansion, and a second material having a second coefficient of thermal expansion that is different from the first coefficient of thermal expansion.

A heat exchanger is configured to adjust a flow restriction of flow passages through the heat exchanger in response to changes in temperature of elements that define at least a portion of the flow passages. The elements include a first material having a first coefficient of thermal expansion, and a second material having a second coefficient of thermal expansion that is different from the first coefficient of thermal expansion.

A heat exchanger with at least one plate includes main dimples between which secondary dimples are formed which are flatter and/or smaller with respect to their dimensions as seen in a plan view. A depth of the secondary dimples may be at most 0.5 times a channel height and/or at most 0.5 times the depth of the main dimples.

Methods and systems are provided for heat exchangers including a first outer plate, a second outer plate, and an intermediate plate. The intermediate plate is positioned between the outer plates. Fluid flow passages are formed between the intermediate plate and each of the outer plates.

The invention relates to a heat exchanger plate (10) of a heat exchanger, the heat exchanger plate (10) comprising two faces (12, 13) extending between two lateral edges and two longitudinal edges (15) of said heat exchanger plate (10). The heat exchanger plate (10) comprises at least an opening (16) extending from a first face (12) to a second face (13) of the heat exchanger plate (10). The opening (16) is delimited by a collar (17) that is arranged around the opening (16). The heat exchanger plate (10) comprises at least a dimple (18) protruding above at least one of the faces (12, 13). Said dimple (18) comprises at least a flat area (19) and a sloped area (20), said sloped area (20) being interposed between the collar (17) and the flat area (19).

A heat transfer plate includes a heat transfer area provided with a heat transfer pattern comprising elongate alternately arranged heat transfer ridges and valleys, a respective top portion of the ridges extending in a top plane and a respective bottom portion of the valleys extending in a bottom plane. The heat transfer ridges comprise ridge contact areas within which the ridges are arranged to abut an adjacent first heat transfer plate. Within at least half of the heat transfer area, the top portions of the ridges have a first width w1, and the bottom portions of the valleys have a second width w2, w1≠w2. The top portion of a number of first heat transfer ridges of the heat transfer ridges, within a respective first ridge contact area of the ridge contact areas, has a third width w3, wherein, if w1>w2 then w3<w1, and, if w1<w2 then w3>w1.

A heat sink includes a base plate; a cover overlapping the base plate; fins, each having a plate-like shape projecting from the base plate in a direction perpendicular to the base plate, located between the base plate and the cover; one or a plurality of first fin groups composed of a plurality of the fins arranged with a gap therebetween in a first direction; and one or a plurality of second fin groups composed of a plurality of the fins arranged with a gap therebetween in the first direction, and adjacent to the first fin group with a gap therebetween in a second direction. Positions in the first direction of the fins belonging to the second fin group are displaced with respect to positions in the first direction of the fins belonging to the first fin group. Each of the fines has an S-shape.

A heat sink includes a base plate; a cover overlapping the base plate; fins, each having a plate-like shape projecting from the base plate in a direction perpendicular to the base plate, located between the base plate and the cover; one or a plurality of first fin groups composed of a plurality of the fins arranged with a gap therebetween in a first direction; and one or a plurality of second fin groups composed of a plurality of the fins arranged with a gap therebetween in the first direction, and adjacent to the first fin group with a gap therebetween in a second direction. Positions in the first direction of the fins belonging to the second fin group are displaced with respect to positions in the first direction of the fins belonging to the first fin group. Each of the fines has an S-shape.