GasModels Network Data Format
The Network Data Dictionary
Internally GasModels utilizes a dictionary to store network data. The dictionary uses strings as key values so it can be serialized to JSON for algorithmic data exchange. GasModels can utilize this serialization as a text file, however GasModels does not support backwards compatibility for such serializations. When used as serialization, the data is assumed to be in per_unit (non dimenisionalized) or SI units.
The network data dictionary structure is roughly as follows:
{
"name":<string>, # a name for the model
"temperature":<float>, # gas temperature. SI units are kelvin
"is_per_units":<int>, # Whether or not the file is in per unit (non dimensional units) or SI units.
"is_english_units":<int>, # Whether or not the file is in english units
"gas_molar_mass":<float>, # molecular mass of the gas. SI units are kg/mol
"gas_specific_gravity":<float>, # the specific gravity of the gas. Non-dimensional.
"multinetwork":<boolean>, # flag for whether or not this is multiple networks
"base_length":<float>, # Base for non-dimensionalizing space (length). Si units are m
"base_flow":<float>, # Base for non-dimensionalizing mass flow. SI units are kg/s
"base_pressure":<float>, # Base for non-dimensionalizing pressure. SI units are pascal
"base_time":<float>, # Base for non-dimensionalizing time. SI units are s
"compressibility_factor":<float>, # Gas compressability. Non-dimensional.
"specific_heat_capacity_ratio":<float>, # Gas compressability. Non-dimensional.
"sound_speed":<float>, # Speed of sound through the gas. SI units are m/s.
"R":<float>, # Universal Gas constant. SI units are J/mol/K.
"junction":{
"1":{
"p_max": <float>, # maximum pressure. SI units are pascals
"p_min": <float>, # minimum pressure. SI units are pascals
"p_nominal": <float>, # nominal pressure. SI units are pascals
"status": <int>, # status of the component (0 = off, 1 = on). Default is 1.
"lat":<float>, # latitude position of the junction (optional)
"lon":<float>, # latitude position of the junction (optional)
...
},
"2":{...},
...
},
"delivery":{
"1":{
"junction_id": <float>, # junction id
"withdrawal_max": <float>, # the maximum mass flow demand. SI units are kg/s.
"withdrawal_min": <float>, # the minimum mass flow demand. SI units are kg/s.
"withdrawal_nominal": <float>, # nominal mass flow demand. SI units are kg/s.
"priority": <float>, # priority for serving the variable load. High numbers reflect a higher desired to serve this load.
"bid_price": <float>, # price for buying gas at the delivery.
"is_dispatchable": <int>, # whether or not the unit is dispatchable (0 = delivery should consume withdrawl_nominal, 1 = delivery can consume between withdrawal_min and withdrawal_max).
"status": <int>, # status of the component (0 = off, 1 = on). Default is 1.
...
},
"2":{...},
...
},
"receipt":{
"1":{
"junction_id": <float>, # junction id
"injection_min": <float>, # the minimum mass flow gas production. SI units are kg/s.
"injection_max": <float>, # the maximum mass flow gas production. SI units are kg/s.
"injection_nominal": <float>, # nominal mass flow production at standard density. SI units are kg/s.
"dispatchable": <int>, # whether or not the unit is dispatchable (0 = receipt should produce injection_nominal, 1 = receipt can produce between injection_min and injection_max).
"offer_price": <float>, # price for selling gas at the receipt.
"status": <int>, # status of the component (0 = off, 1 = on). Default is 1.
...
},
"2":{...},
...
},
"transfer":{
"1":{
"junction_id": <float>, # junction id
"withdrawal_max": <float>, # the maximum mass flow demand. SI units are kg/s.
"withdrawal_min": <float>, # the minimum mass flow demand. SI units are kg/s. (can be negative, in which case it is gas injection)
"withdrawal_nominal": <float>, # nominal mass flow demand. SI units are kg/s.
"offer_price": <float>, # price for selling gas at the receipt.
"bid_price": <float>, # price for buying gas at the delivery.
"is_dispatchable": <int>, # whether or not the unit is dispatchable (0 = transfer should consume withdrawl_nominal, 1 = transfer can consume between withdrawal_min and withdrawal_max).
"status": <int>, # status of the component (0 = off, 1 = on). Default is 1.
...
},
"2":{...},
...
},
"pipe":{
"1":{
"length": <float>, # the length of the connection. SI units are m.
"fr_junction": <int>, # the "from" side junction id
"to_junction": <int>, # the "to" side junction id
"friction_factor": <float>, # the friction component of the resistance term of the pipe. Non dimensional.
"diameter": <float>, # the diameter of the connection. SI units are m.
"status": <int>, # status of the component (0 = off, 1 = on). Default is 1.
"p_max": <float>, # maximum pressure. SI units are pascals
"p_min": <float>, # minimum pressure. SI units are pascals
"is_bidirectional": <int>, # flag for whether or not flow can go in both directions
...
},
"2":{...},
...
},
"compressor":{
"1":{
"fr_junction": <int>, # the "from" side junction id
"to_junction": <int>, # the "to" side junction id
"c_ratio_min": <float>, # minimum multiplicative pressure change (compression or decompressions). Compression only goes from f_junction to t_junction (1 if flow reverses).
"c_ratio_max": <float>, # maximum multiplicative pressure change (compression or decompressions). Compression only goes from f_junction to t_junction (1 if flow reverses).
"status": <int>, # status of the component (0 = off, 1 = on). Default is 1.
"operating_cost": <float>, # The cost per W of running the compressor
"power_max": <float>, # Maximum power consumed by the compressor. SI units is W
"type": <int>, # type of the compressor (two way compression or not, one way flow or not, etc.)
...
},
"2":{...},
...
}
"short_pipe":{
"1":{
"fr_junction": <int>, # the "from" side junction id
"to_junction": <int>, # the "to" side junction id
"status": <int>, # status of the component (0 = off, 1 = on). Default is 1.
"is_bidirectional": <int>, # flag for whether or not flow can go in both directions
...
},
"2":{...},
...
}
"valve":{
"1":{
"fr_junction": <int>, # the "from" side junction id
"to_junction": <int>, # the "to" side junction id
"status": <int>, # status of the component (0 = off, 1 = on). Default is 1.
"is_bidirectional": <int>, # flag for whether or not flow can go in both directions
...
},
"2":{...},
...
}
"regulator":{
"1":{
"fr_junction": <int>, # the "from" side junction id
"to_junction": <int>, # the "to" side junction id
"reduction_factor_min": <float>, # minimum multiplicative pressure change (compression or decompressions). Compression only goes from f_junction to t_junction (1 if flow reverses).
"reduction_factor_max": <float>, # maximum multiplicative pressure change (compression or decompressions). Compression only goes from f_junction to t_junction (1 if flow reverses).
"status": <int>, # status of the component (0 = off, 1 = on). Default is 1.
"is_bidirectional": <int>, # flag for whether or not flow can go in both directions
...
},
"2":{...},
...
}
"resistor":{
"1":{
"fr_junction": <int>, # the "from" side junction id
"to_junction": <int>, # the "to" side junction id
"drag": <float>, # the drag factor of resistors. Non dimensional.
"status": <int>, # status of the component (0 = off, 1 = on). Default is 1.
"is_bidirectional": <int>, # flag for whether or not flow can go in both directions
...
},
"2":{...},
...
}
"loss_resistor":{
"1":{
"fr_junction": <int>, # the "from" side junction id
"to_junction": <int>, # the "to" side junction id
"p_loss": <float>, # constant pressure loss along the edge
"status": <int>, # status of the component (0 = off, 1 = on). Default is 1.
"is_bidirectional": <int>, # flag for whether or not flow can go in both directions
...
},
"2":{...},
...
}
"storage":{
"1":{
"id": <int>, # id of the junction in which storage is located
"well_diameter": <float>, # diameter of the wells
"well_depth": <float>, # depth of the wells
"well_friction_factor": <float>, # friction factor of the wells
"reservoir_p_max": <float>, # maximum pressure of the reservoir
"base_gas_capacity": <float>, # base gas capacity in reservoir (SI units: kg)
"total_field_capacity": <float>, # total gas capacity in reservoir (SI units: kg)
"initial_field_capacity_percent": <float>, # initial gas in reservoir as a percentage of total capacity
"reduction_factor_max": <float> # maximum reduction factor of the regulator
"c_ratio_max": <float>, # maximum compression ratio of the compressor
"status": <int>, # status of the component (0=off, 1=on). Default is 1.
"flow_injection_rate_min": <float>, # minimum flow rate at which gas can be injected into storage. SI units is kg/s
"flow_injection_rate_max": <float>, # maximum flow rate at which gas can be injected into storage. SI units is kg/s
"flow_withdrawal_rate_min": <float>, # minimum flow rate at which gas can be withdrawn from storage. SI units is kg/s
"flow_withdrawal_rate_max": <float>, # maxium flow rate at which gas can be withdrawn storage. SI units is kg/s
...
},
"2":{...},
...
}
}All data is assumed to have consistent units (i.e. SI units or non-dimensionalized units)
The following commands can be used to explore the network data dictionary,
network_data = GasModels.parse_file("gaslib-40.m")
display(network_data)