The model is a Acausal component-based model containing :

• The discrete convection-diffusion component giving a temperature discretisation through time and space : u(t)[x]
• The layer instantiation, function of n size of u(t)[x]
• Ploting of the solution

Note : We are modelizing a U-Tube case-B Borehole

Note before reading : the description is made for the branch "master", the second branch is about recent öodification for heat flow control system.

1 - Today, the working code is called "BHE_3D_CODE", it contain the layer-discretisation model solving and plotting. And maybe some of the variables are "undefined" like timer (or others) but you can just add a definition before instantiation of the model "soil_..._layer". The compilation is quite long for the first run. "BHE_3D_CODE" contain the computation with the variables layers of MRCTM.

2 - You can have acces to the "include files" which contain data's computation and the components declaration. The "function_component_thermal.jl" contain the main features, the component declaration. So the focus have to be done on that. note : it uses the "wall_component" which is a serie of R-C-R-C-R (like a wall) and a component soil_temp which is a constant-voltage (temperature).

3 - The component called "soil_MTRCM_var_pin_var_ver_2" contain the most updated work. So the focus have to be done on that. note : it uses the "soil_MRCTM" which is layers of MRCTM model, a component soil_temp which is a constant-voltage (temperature) and of course 2 fluid discretisation computation (with two different velocity sign).

4 - The model also include now computation for the heat exchange with the ambient air/first layer of soil and for the Heat exchange between all layers.

• 10 meters of soil - 10 layers for MRCTM model
• Initial Temperature at 20 °C for the whole model
• 41 days of simulation
• velocity of the internal fluid of 0,0001 m/s
• Ambient Air at 15 °C
• boundaries condition on the fluid-discretization = [T_1(t, 0.0) ~ T_soil+2, T_1(0.0, x) ~ T_soil, T_2(0.0, x) ~ T_soil, T_1(t, xmax) ~ T_2(t, 0.0)]

The soil is being heat by the fluid inside the borehole which is for instance at 22°C. You can see that the heat propagate throught time inside the soil layers "Discrete radius". We can also see that the more we go deep inside the soil (discrete depth), the less heat is propagating.

• 10 meters of soil - 10 layers for MRCTM model
• Initial Temperature at 20 °C for the whole model
• 600 days of simulation
• velocity of the internal fluid of 0,000001 m/s
• Ambient Air at 20 °C
• boundaries condition on the fluid-discretization = [T_1(t, 0.0) ~ T_soil+2, T_1(0.0, x) ~ T_soil, T_2(0.0, x) ~ T_soil, T_1(t, xmax) ~ T_2(t, 0.0)]

• 10 meters of soil - 10 layers for MRCTM model
• Initial Temperature at 20 °C for the whole model
• 41 days of simulation
• velocity of the internal fluid of 0,000001 m/s
• Ambient Air at 15 °C
• boundaries condition on the fluid-discretization = [T_1(t, 0.0) ~ T_soil+2, T_1(0.0, x) ~ T_soil, T_2(0.0, x) ~ T_soil, T_1(t, xmax) ~ T_2(t, 0.0)]

The Y axis is the time axis. At time 0 everything is at 20 °C. Then the fluid at layer 0 (top of the borehole) is being heat at 22 °C every time. This heat propagate inside the fluid in depth.

Same as before.

The Y axis is the time axis. This fluid 2 is connected at layer 10 with the precedent fluid. The heat at the end of time and at the layer 0 is around 20.3 °C.

Same as before.

Result can be explain by this following picture. Heat enter in pipe 1 inlet and heat propagate inside through time.

Same as before but the ambiant air is at 20 °C and during 600 days.

[1] Short-term simulation of ground heat exchanger with an improved TRCM Philippe Pasquier*, Denis Marcotte Department of Civil, Geological and Mining Engineering, École Polytechnique de Montréal, C.P. 6079 Succ. Centre-Ville, Montréal, Québec, Canada H3C 3A7

[2] A review of methods to evaluate borehole thermal resistances in geothermal heat-pump systems Louis Lamarche ∗, Stanislaw Kajl, Benoit Beauchamp École de Technologie Supérieure, 1100 Notre-Dame Ouest, Montréal, Canada H3C 1K3

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