A condensing portion is formed such that a first refrigerant flow path through which a gas-phase refrigerant flowing into a refrigerant inlet flows and a first heat-medium flow path through which a heat medium flows overlap each other in a stacking direction of plates. A gas-liquid separator separates the refrigerant into gas-phase refrigerant and liquid-phase refrigerant and discharges the liquid-phase refrigerant. A subcooling portion is disposed on one side in the stacking direction with respect to the condensing portion, is formed such that a second refrigerant flow path through which the liquid-phase refrigerant discharged from the gas-liquid separator flows toward a refrigerant outlet and a second heat-medium flow path through which the heat medium flows overlap each other in the stacking direction.

A condensing portion is formed such that a first refrigerant flow path through which a gas-phase refrigerant flowing into a refrigerant inlet flows and a first heat-medium flow path through which a heat medium flows overlap each other in a stacking direction of plates. A gas-liquid separator separates the refrigerant into gas-phase refrigerant and liquid-phase refrigerant and discharges the liquid-phase refrigerant. A subcooling portion is disposed on one side in the stacking direction with respect to the condensing portion, is formed such that a second refrigerant flow path through which the liquid-phase refrigerant discharged from the gas-liquid separator flows toward a refrigerant outlet and a second heat-medium flow path through which the heat medium flows overlap each other in the stacking direction.

A heat exchanger includes a body that includes an at least two opposing surfaces and the at least two opposing surfaces are a trapezoidal. The body of the heat exchanger also includes, an area of cross sectional flow channels through the body. The area of cross-sectional flow channels in a direction perpendicular to the bases of the trapezoid increase or decrease between the two bases.

A heat exchanger includes a body that includes an at least two opposing surfaces and the at least two opposing surfaces are a trapezoidal. The body of the heat exchanger also includes, an area of cross sectional flow channels through the body. The area of cross-sectional flow channels in a direction perpendicular to the bases of the trapezoid increase or decrease between the two bases.

A stack type heat exchanger includes a plurality of first plates and a plurality of second plates. At least one of the respective first plates and the respective second plates has a protrusion protruding from a main body of the first plate or the second plate toward a first flow path, the protrusion being located at a peripheral portion of a tank space in the first flow path. The first plate and the second plate are joined to each other through the protrusion. The protrusion has a top portion and a side wall portion. A part of the side wall portion adjacent to the tank space has a thick structure portion, an entire thickness of the thick structure portion being thick in a direction perpendicular to the stacking direction.

A stack type heat exchanger includes a plurality of first plates and a plurality of second plates. At least one of the respective first plates and the respective second plates has a protrusion protruding from a main body of the first plate or the second plate toward a first flow path, the protrusion being located at a peripheral portion of a tank space in the first flow path. The first plate and the second plate are joined to each other through the protrusion. The protrusion has a top portion and a side wall portion. A part of the side wall portion adjacent to the tank space has a thick structure portion, an entire thickness of the thick structure portion being thick in a direction perpendicular to the stacking direction.

An object of the present invention is to provide a diffusion bonding heat exchanger with which it is possible to reduce a thermal stress that is generated due to heat exchange between fluids significantly different from each other in temperature even in a case where the number of stacked heat transfer plates is made large. A diffusion bonding heat exchanger (100) includes a core (1) in which a plurality of heat transfer plates (HP) are stacked and diffusion-bonded to each other. The core includes a plurality of flow path blocks (40) each of which is configured to include a plurality of flow path layers (30) and a partition wall layer (50) that divides the plurality of flow path blocks. A thickness (t3) of the partition wall layer in a stacking direction is larger than an interval (t2) between flow paths arranged in the stacking direction.

A compact heat exchanger is provided, in which multiple streams can flow within the same layer or layers, and different fluids may flow in alternating channels within the same layer as well as flowing in alternating layers. Having fluids in alternating channels—as compared to only alternating layers within the same layer—increases the direct surface area between the fluids (the primary surface area) for heat transfer, thereby increasing the rate and efficiency of heat transfer. Methods of making and using the heat exchanger are also provided.

A water heater according to the present invention includes: a heating unit that includes a burner provided to cause a combustion reaction from air and fuel, and that is provided to generate heated water by using heat generated by the combustion reaction; and a humidifier unit that generates water steam by evaporating water using a combustion gas generated by the combustion reaction and discharged from the heating unit, and provides the water steam together with the air to the burner.

A plate-stacked heat exchanger is proposed which exchanges heat with high heat exchange efficiency in flow paths each including an internal space bulging outward between two heat transfer plates. A flow path forming portion includes a plurality of flow path bulging portions that bulges outward of a heat exchanger plate and forms heat exchange flow paths of a first heating medium therein, and a header portion includes a communication hole communicating with the header portion of an adjacent heat exchanger plate, and a flow path forming portion-side expanded portion expanding from the communication hole toward the flow path forming portion, and the flow path forming portion-side expanded portion communicates with the plurality of heat exchange flow paths. Consequently, heat can be exchanged in a greater width. Therefore, a high heat exchange rate can be obtained.