r.green.gshp.theoretical - GRASS GIS manual

NAME

r.green.gshp.theoretical - Calculate the Ground Source Heat Pump potential

KEYWORDS

SYNOPSIS

r.green.gshp.theoretical

r.green.gshp.theoretical --help

r.green.gshp.theoretical [-d] ground_conductivity=name [heating_season_raster=name] [heating_season_value=double] [power_value=double] [ground_capacity_raster=name] [ground_capacity_value=double] [ground_temp_raster=name] [ground_temp_value=double] [borehole_radius=double] [borehole_resistence=double] [borehole_length=double] [pipe_radius=double] [number_pipes=integer] [grout_conductivity=double] [fluid_limit_temperature=double] [lifetime=integer] power=name energy=name [length=name] [--overwrite] [--help] [--verbose] [--quiet] [--ui]

Flags:

-d: Debug with intermediate maps
--overwrite: Allow output files to overwrite existing files
--help: Print usage summary
--verbose: Verbose module output
--quiet: Quiet module output
--ui: Force launching GUI dialog

Parameters:

ground_conductivity=name [required]: Raster with depth-averaged ground thermal conductivity λ [W m-1 K-1]
heating_season_raster=name: Raster with the Heating Season [0-365] days
heating_season_value=double: Heating Season [0-365] days; Options: 0-365; Default: 180.
power_value=double: Power value in kW; Default: nan
ground_capacity_raster=name: Raster with depth-averaged ground thermal capacity ρc [MJ m-3 K-1]
ground_capacity_value=double: Value with depth-averaged ground thermal capacity ρc [MJ m-3 K-1]; Default: 2.5
ground_temp_raster=name: Raster with the initial ground temperature T0 [°C]
ground_temp_value=double: Value with the initial ground temperature T0 [°C]; Default: 10.
borehole_radius=double: Borehole radius [m]; Default: 0.075
borehole_resistence=double: Borehole thermal resistence [m K W-1]; Default: nan
borehole_length=double: Borehole length [m]; Default: 100
pipe_radius=double: Pipe radius [m]; Default: 0.016
number_pipes=integer: Number of pipes in the borehole; Default: 4
grout_conductivity=double: Thermal conductivity of the borehole filling (geothermal grout) [W m-1 K-1]; Default: 2
fluid_limit_temperature=double: Minimum or maximum fluid temperature [°C]; Default: -2
lifetime=integer: Simulated lifetime of the plant [years]; Default: 50
power=name [required]: Name of output raster map with the geothermal power potential [W]
energy=name [required]: Name of output raster map with the geothermal energy potential [MWh]
length=name: Name of output raster map with the geothermal length of the BHE [m]

DESCRIPTION
NOTES
EXPLANATION
EXAMPLES
SEE ALSO
AUTHORS
REFERENCES

DESCRIPTION

r.green.gshp.theoretical assess the shallow geothermal potential defined as the thermal power exchanged by a Borehole Heat Exchanger of a certain depth. This potential depends on the thermal properties of the ground and the plant features. This module returns two output raster maps with the the energy potential (MWh/year) and the power potential (W). In this module the output is the theoretical maximum energy that can be converted in the ideal case without considering the financial and spatial constraints.

NOTES

The required inputs are the the thermal conductivity. If not specific values are indicated, reference values have been assumed for the ground features and the plant.

EXPLANATION

r.green.gshp.theoretical calculates the potential of shallow geothermal energy by means of and empirical relationship proposed by Casasso et al. (2016) as:

P_gshp=8*(T₀ - T_lim) λ L t'_c/(-0.619 t'_c log(u'_s)-0.455 t'_c-1.619+4 π R_b)

where
T₀ is the undisturbed ground temperature (°C),
T_lim the threshold temperature of the heat carrier fluid setting to 2°C,
λ is the the thermal conductivity of the ground (W/(mK)),
L the borehole length (m),
t'_c is is the operating time ratio ,
u'_s is a parameter depending on the simulaion time and the borehole radius ,
R_b is the thermal resistance (K/W)

EXAMPLES

This example is based on the case-study of the EUSALP region, located in Europe and covering part of Italian, Slovenian, Austrian, German, Swiss and France territories. The data can be downloades at the following repositories EUSALP dataset .

r.green.gshp.theoretical \
    ground_conductivity=conductivity \
    heating_season_raster=season_heating \
    ground_temp_raster=ground_temperature \
    ground_capacity_value=2.3 \
    power=gpot_power \
    energy=gpot_energy \

AUTHORS

Pietro Zambelli (Eurac Research, Bolzano, Italy), Tested by and manual written by Giulia Garegnani

REFERENCES

Alessandro Casasso, Rajandrea Sethi, 2016,
"G.POT: A quantitative method for the assessment and mapping of the shallow geothermal potential"
Energy 106, p 765 --
http://dx.doi.org/10.1016/j.energy.2016.03.091

SOURCE CODE

Available at: r.green.gshp.theoretical source code (history)