Plate heat exchanger, heat pump device including plate heat exchanger, and heat pump type of cooling, heating, and hot water supply system including heat pump device

Abstract

A plate heat exchanger includes heat transfer plates having openings at four corners thereof, having outer wall portions at their edges, and stacked together. The heat transfer plates are partially brazed together such that a first flow passage for first fluid and a second flow passage for second fluid are alternately arranged, with a heat transfer plate interposed between these flow passages, the openings communicating with each other, forming a first header allowing the first fluid to flow into and out of the first flow passage and a second header allowing the second fluid to flow into and out of the second flow passage. One heat transfer plate located between the first or second flow passage is formed by stacking two metal plates. Space between the metal plates includes a fine flow passage located within a heat exchange region, and a peripheral leakage passage outward of the fine flow passage.