HEAT-EXCHANGE PIPE, HEAT-EXCHANGER UNIT USING SAME, AND CONDENSING BOILER USING SAME

A heat-exchanger unit according to the present invention comprises: a sensible-heat heat-exchange portion arranged in a sensible-heat heat-exchange area for receiving sensible heat generated by a combustion reaction and thereby heating water, the sensible-heat heat-exchange portion having a sensible-heat heat-exchange pipe for receiving the water and causing same to flow through the interior thereof, thereby forming a sensible-heat channel along which the water flows; and a latent-heat heat-exchange portion positioned downstream of the sensible-heat heat-exchange area with reference to a first reference direction along which combustion gas generated during the combustion reaction flows, the latent-heat heat-exchange portion being arranged in a latent-heat heat-exchange area for receiving latent heat generated during a phase change of the combustion gas and thereby heating the water, the latent-heat heat-exchange portion having a latent-heat heat-exchange pipe for receiving the water and causing same to flow through the interior thereof. The latent-heat heat-exchange pipe comprises multiple latent-heat straight portions extending in a second reference direction perpendicular to the first reference direction, the multiple latent-heat straight portions being arranged to be spaced apart from each other along a third reference direction perpendicular to the first reference direction and to the second reference direction so as to form a latent-heat channel along which the water flows, and which communicates with the sensible-heat channel. The latent-heat straight portions have inner spaces formed in flat shapes such that the width thereof along the third reference direction is smaller than the length