The invention relates to a spiral-tube
heat exchanger which comprises a
refrigerant channel and a
water channel, and is characterized in that a spiral tube is arranged inside an outer tube, and the two ends of the spiral tube are exposed outside; the tube wall inside the outer tube where the spiral tube is arranged takes on
screw thread shape; and the inner wall of the outer tube is matched with crest of
screw thread of the outer wall of the spiral tube, and the inner wall of the outer tube is connected with the crest of
screw thread of the outer wall of the spiral tube into a whole by
soldering, so that a sealing surface is formed. The inner wall of the spiral tube also takes on screw thread shape. The two ends of the outer tube are provided with flareouts. The
water channel is arranged at the inner side of the spiral tube, and the
refrigerant channel is positioned at a thread channel between the outer side of the spiral tube and the inner side of the outer tube. The spiral-tube
heat exchanger has the advantages that
refrigerant is contacted with water by a
clapboard, so that the
heat transfer efficiency is high, the
thermal resistance is low, the flow path of the refrigerant can be greatly increased within a limited space, full heat exchange can be realized, and the heat exchange capability of the
heat exchanger can be improved within a limited space. The spiral-tube heat exchanger can be widely applied to the products such as a wall hanging instant heating type
heat pump water heater and the like which need smaller installation space and high
unit volume heat exchange quantity.