HYDRUS 2.x Tutorial 5.12: Ground Source Heat Pump
Ground Source Heat Pump
This tutorial shows modeling of a closed loop ground source heat pump (GSHP). The GSHP is one of the most efficient residential heating and cooling systems available today, with heating efficiencies 50 to 70% higher than other heating systems and cooling efficiencies 20 to 40% higher than available air conditioners. For closed loop systems, water or antifreeze solution is circulated through plastic pipes buried beneath the earth's surface. During the winter, the fluid collects heat from the earth and carries it through the system and into the building. During the summer, the system reverses itself to cool the building by pulling heat from the building, carrying it through the system and placing it in the ground. The heat exchanger pipes are one of the units of GSHPs that are buried in the ground at a certain depth and water circulates through them to extract/dissipate heat from/to the ground.
The goal of this study with HYDRUS is to model the system and to evaluate "water temperature" that comes out of the loops after it has been in contact with the surrounding soil medium.
Download the project (31 MB)
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Domain Geometry
The computational domain consists of three elements - heat exchanger tube (dark blue), flowing medium - water (pale blue), and the surrounding soil (brown). Note that HYDRUS models "flowing medium" as a soil layer with a unit porosity and a high hydraulic conductivity. The bottom part of the image shows the detail of the pipe.
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FE-Mesh
The finite element mesh has about 88 thousand nodes and 470 thousand 3D elements. The bottom part of the image shows the detail of the tube exchanger.
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Results - Temperature
This figure shows the temperature distribution in and around the heat exchanger and how heat dissipates in the soil profile.
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