Heat exchanger and its manufacturing method

摘要

A heat exchanger is provided which has an easy-to-manufacture structure, is inexpensive, and has high quality and reliability while keeping high heat exchanging performance. The heat exchanger has first substrates (26) having first slits (30) and second slits (40) disposed substantially in parallel, and second substrates (28) having third slits (50) with substantially the same shape as that of first slits (30). The longitudinal length of second substrates (28) is set shorter than that of second slits (40). First substrates (26) and second substrates (28) are stacked so that first slits (30) communicate with third slits (50). First slits (30) and third slits (50) form tube external flow channels (60). Second slits (40) and second substrates (28) form tube internal flow channels (70). The heat exchanging section including only tubes can be formed of substrates having a slit, so that the heat exchanger can be manufactured easily and inexpensively.