GEOTHERMAL UNIT

To sufficiently exert a performance of a heat utilization apparatus.SOLUTION: A geothermal unit includes: a heat source-side piping system 10 forming a circulation flow channel of a heat medium liquid between an underground side and a ground side; a utilization-side piping system 30 forming a circulation flow channel of a liquid for utilizing heat at the ground side independently from the heat source-side piping system 10; a first heat exchanger 20 exchanging heat between the heat medium liquid flowing in the heat source-side piping system 10 and the liquid flowing in the utilization-side piping system 30; an auxiliary piping system 40 branched from the utilization-side piping system 30 at a downstream side with respect to the first heat exchanger 20, and joined to the utilization-side piping system 30 at a downstream side with respect to a branch point; a second heat exchanger 50 exchanging heat between the liquid flowing in the auxiliary piping system 40 and the air outside of the auxiliary piping system 40 in a passage of the auxiliary piping system 40; and a cylindrical duct 70 disposed in the second heat exchanger 50 for circulating the air.SELECTED DRAWING: Figure 1 【課題】 熱利用機器の性能を十分に発揮する。【解決手段】 地中側と地上側の間で熱媒体液の循環流路を形成する熱源側配管系統１０と、熱源側配管系統１０とは独立して地上側で熱利用するための液体の循環流路を形成する利用側配管系統３０と、熱源側配管系統１０を流れる熱媒体液と利用側配管系統３０を流れる液体との熱交換を行う第一の熱交換器２０と、第一の熱交換器２０よりも下流側で利用側配管系統３０から分岐され、その分岐点よりも下流側で利用側配管系統３０に合流する補助配管系統４０と、補助配管系統４０の経路中にて補助配管系統４０を流れる液体と補助配管系統４０の外側の空気との熱交換を行う第二の熱交換器５０と、第二の熱交換器５０を内在して空気を流通させる筒状のダクト７０とを具備して地中熱利用装置を構成した。【選択図】 図１