Thermal Heating

Contents

Overview | Asset Structure | Flow Equations | Input File (Standard Format) | Types - Asset Structure | Constructors | Examples | Best Practices | Input File (Advanced Format)

Overview

Thermal Heating assets in MacroEnergy.jl represent combustion-based heating technologies that convert fuel (such as natural gas, or other fuels) into heat for district or building heating systems. These assets can represent boilers or furnaces supplying district networks. They are defined using either JSON or CSV input files placed in the assets directory, typically named with descriptive identifiers like gas_heating.json, or fuel_heating.json.

Asset Structure

A thermal heating plant asset consists of four main components:

1. Transformation Component: Balances the fuel and heat flows
2. Fuel Edge: Represents the fuel supply to the heating unit
3. Heat Edge: Represents the heat production (can have unit commitment operations)
4. CO₂ Edge: Represents the CO₂ emissions

Here is a graphical representation of the thermal heating asset:

Flow Equations

The thermal heating asset follows these stoichiometric relationships:

\[\begin{aligned} \phi_{fuel} &= \phi_{heat} \cdot \epsilon_{fuel\_consumption} \\ \phi_{co2} &= \phi_{fuel} \cdot \epsilon_{emission\_rate} \\ \end{aligned}\]

Where:

• $\phi$ represents the flow of each commodity
• $\epsilon$ represents the stoichiometric coefficients defined in the Conversion Process Parameters section.

Input File (Standard Format)

The easiest way to include a thermal heating asset in a model is to create a new file (either JSON or CSV) and place it in the assets directory together with the other assets.

your_case/
├── assets/
│   ├── fuel_heating.json    # or fuel_heating.csv
│   ├── other_assets.json
│   └── ...
├── system/
├── settings/
└── ...

This file can either be created manually, or using the template_asset function, as shown in the Adding an Asset to a System section of the User Guide. The file will be automatically loaded when you run your Macro model.

The following is an example of a natural gas heating asset input file:

{
    "NaturalGasHeating": [
        {
            "type": "ThermalHeating",
            "instance_data": [
                {
                    "id": "SE_natgas_boiler_1",
                    "location": "SE",
                    "fuel_commodity": "NaturalGas",
                    "co2_sink": "co2_sink",
                    "capacity_size": 50,
                    "fuel_consumption": 1.15,
                    "emission_rate": 0.18,
                    "investment_cost": 20000,
                    "fixed_om_cost": 1200,
                    "variable_om_cost": 2.0,
                    "uc": false,
                    "ramp_up_fraction": 0.8,
                    "ramp_down_fraction": 0.8
                }
            ]
        }
    ]
}

The following tables outline the attributes that can be set for a thermal heating asset.

Essential Attributes

Conversion Process Parameters

The following set of parameters control the conversion process and stoichiometry of the thermal heating asset (see Flow Equations for more details).

Constraints Configuration

Thermal Heating assets can have different constraints applied to them, and the user can configure them using the following fields:

For example, if the user wants to apply the BalanceConstraint to the transformation component and the CapacityConstraint to the heat edge, the constraints fields should be set as follows:

{
    "transform_constraints": {
        "BalanceConstraint": true
    },
    "heat_constraints": {
        "CapacityConstraint": true
    }
}

Users can refer to the Adding Asset Constraints to a System section of the User Guide for a list of all the constraints that can be applied to the different components of a thermal heating asset.

Default constraints

To simplify the input file and the asset configuration, the following constraints are applied to the thermal heating asset by default:

• Balance constraint (applied to the transformation component)
• Capacity constraint (applied to the heat edge)
• Ramping limits constraint (applied to the heat edge)

Unit commitment constraints (when uc is set to true):

• Minimum up and down time constraint (applied to the heat edge)

Investment Parameters

Additional Investment Parameters

Maximum and minimum capacity constraints

If MaxCapacityConstraint or MinCapacityConstraint are added to the constraints dictionary for the heat edge, the following parameters are used by Macro:

Economic Parameters

Operational Parameters

Additional Operational Parameters

Unit commitment parameters (when uc is set to true)

Minimum flow constraint

If MinFlowConstraint is added to the constraints dictionary for the heat edge, the following parameter is used:

Ramping limit constraint

If RampingLimitConstraint is added to the constraints dictionary for the heat edge, the following parameters are used:

Minimum up and down time constraints

If MinUpTimeConstraint or MinDownTimeConstraint are added to the constraints dictionary for the heat edge, the following parameters are used:

Types - Asset Structure

The ThermalHeating asset is defined as follows:

struct ThermalHeating{T} <: AbstractAsset
    id::AssetId
    heating_transform::Transformation
    heat_edge::Union{Edge{<:Heat},EdgeWithUC{<:Heat}}
    fuel_edge::Edge{<:T}
    co2_edge::Edge{<:CO2}
end

Constructors

Default constructor

ThermalHeating(id::AssetId, heating_transform::Transformation, heat_edge::Union{Edge{<:Heat},EdgeWithUC{<:Heat}}, fuel_edge::Edge{<:Fuel}, co2_edge::Edge{<:CO2})

Factory constructor

make(asset_type::Type{ThermalHeating}, data::AbstractDict{Symbol,Any}, system::System)

Examples

This section contains examples of how to use the thermal heating asset in a Macro model.

Gas Heat Pump

This example shows a gas heat pump using natural gas as fuel. The asset has an existing capacity that is only allowed to be retired. A MinFlowConstraint constraint is applied to the heat edge with a minimum flow fraction of 0.5. The asset has an availability time series loaded from a CSV file.

JSON Format:

Note that the global_data field is used to set the fields and constraints that are common to all instances of the same asset type.

{
    "GasHeatPump": [
        {
            "type": "ThermalHeating",
            "instance_data": [
                {
                    "id": "SE_natural_gas_heating_1",
                    "location": "SE",
                    "timedata": "NaturalGas",
                    "fuel_commodity": "NaturalGas",
                    "fuel_start_vertex": "natgas_source",
                    "co2_sink": "co2_sink",
                    "uc": false,
                    "can_retire": true,
                    "can_expand": false,
                    "existing_capacity": 500.0,
                    "capacity_size": 50.0,
                    "fuel_consumption": 1.2,
                    "emission_rate": 0.18,
                    "fixed_om_cost": 6000,
                    "variable_om_cost": 5.0,
                }
            ]
        }
    ]
}

CSV Format:

Multiple Natural Gas Heating Units in Different Zones

This example shows three natural gas–fired heating units using natural gas as fuel. Each asset has an existing capacity that is only allowed to be retired. The assets are configured without unit commitment variables.

JSON Format:

{
    "NaturalGasHeating": [
        {
            "type": "ThermalHeating",
            "global_data": {
                "timedata": "NaturalGas",
                "fuel_commodity": "NaturalGas",
                "co2_sink": "co2_sink",
                "heat_constraints": {
                    "MinFlowConstraint": true
                }
            },
            "instance_data": [
                {
                    "id": "MIDAT_natural_gas_heating_1",
                    "location": "MIDAT",
                    "emission_rate": 0.181048235160161,
                    "fuel_consumption": 1.85,
                    "can_retire": true,
                    "can_expand": false,
                    "existing_capacity": 4000.0,
                    "investment_cost": 0.0,
                    "fixed_om_cost": 8000,
                    "variable_om_cost": 4.5,
                    "capacity_size": 100.0,
                },
                {
                    "id": "NE_natural_gas_heating_1",
                    "location": "NE",
                    "emission_rate": 0.181048235160161,
                    "fuel_consumption": 1.90,
                    "can_retire": true,
                    "can_expand": false,
                    "existing_capacity": 6000.0,
                    "investment_cost": 0.0,
                    "fixed_om_cost": 8200,
                    "variable_om_cost": 4.7,
                    "capacity_size": 120.0,
                },
                {
                    "id": "SE_natural_gas_heating_1",
                    "location": "SE",
                    "emission_rate": 0.181048235160161,
                    "fuel_consumption": 1.75,
                    "can_retire": true,
                    "can_expand": false,
                    "existing_capacity": 25000.0,
                    "investment_cost": 0.0,
                    "fixed_om_cost": 7000,
                    "variable_om_cost": 3.9,
                    "capacity_size": 500.0,
                }
            ]
        }
    ]
}

CSV Format:

Best Practices

1. Use global data for common parameters: Use the global_data field to set the fields and constraints that are common to all instances of the same asset type.
2. Set realistic efficiency parameters: Ensure fuel consumption, emission rates, and capture rates are accurate for the technology being modeled
3. Use meaningful IDs: Choose descriptive identifiers that indicate location and technology type
4. Consider unit commitment carefully: Enable unit commitment only when detailed operational modeling is needed
5. Use constraints selectively: Only enable constraints that are necessary for your modeling needs
6. Validate costs: Ensure investment and O&M costs are in appropriate units and time periods
7. Test configurations: Start with simple configurations and gradually add complexity
8. Set appropriate ramp rates: Consider the actual operational characteristics of the technology

Input File (Advanced Format)

Macro provides an advanced format for defining thermal heating assets, offering users and modelers detailed control over asset specifications. This format builds upon the standard format and is ideal for those who need more comprehensive customization.

To understand the advanced format, consider the graph representation and the type definition of a thermal heating asset. The input file mirrors this hierarchical structure.

A thermal heating asset in Macro is composed of a transformation component, represented by a Transformation object, and multiple edges (fuel, heat, CO2), each represented by an Edge object. The input file for a thermal heating asset is therefore organized as follows:

{
    "transforms":{
        // ... transformation-specific attributes ...
    },
    "edges":{
        "fuel_edge": {
            // ... fuel_edge-specific attributes ...
        },
        "heat_edge": {
            // ... heat_edge-specific attributes ...
        },
        "co2_edge": {
            // ... co2_edge-specific attributes ...
        }
    }
}

Each top-level key (e.g., "transforms" or "edges") denotes a component type. The second-level keys either specify the attributes of the component (when there is a single instance) or identify the instances of the component when there are multiple instances.

Below is an example of an input file for a thermal heating asset that sets up multiple thermal heating plants across different regions:

{
    "NaturalGasHeating": [
        {
            "type": "ThermalHeating",
            "global_data": {
                "transforms": {
                    "timedata": "NaturalGas",
                    "constraints": {
                        "BalanceConstraint": true
                    }
                },
                "edges": {
                    "heat_edge": {
                        "commodity": "Heat",
                        "unidirectional": true,
                        "has_capacity": true,
                        "constraints": {
                            "CapacityConstraint": true,
                            "RampingLimitConstraint": true,
                            "MinFlowConstraint": true
                        }
                    },
                    "fuel_edge": {
                        "commodity": "NaturalGas",
                        "unidirectional": true,
                        "has_capacity": false
                    },
                    "co2_edge": {
                        "commodity": "CO2",
                        "unidirectional": true,
                        "has_capacity": false,
                        "end_vertex": "co2_sink"
                    }
                }
            },
            "instance_data": [
                {
                    "id": "MIDAT_natural_gas_heating_1",
                    "transforms": {
                        "emission_rate": 0.181048235160161,
                        "fuel_consumption": 1.85
                    },
                    "edges": {
                        "heat_edge": {
                            "end_vertex": "heat_MIDAT",
                            "can_retire": true,
                            "can_expand": false,
                            "existing_capacity": 4000.0,
                            "investment_cost": 0.0,
                            "fixed_om_cost": 8000,
                            "variable_om_cost": 4.5,
                            "capacity_size": 100.0,
                        },
                        "fuel_edge": {
                            "start_vertex": "natgas_MIDAT"
                        }
                    }
                },
                {
                    "id": "NE_natural_gas_heating_1",
                    "transforms": {
                        "emission_rate": 0.181048235160161,
                        "fuel_consumption": 1.90
                    },
                    "edges": {
                        "heat_edge": {
                            "end_vertex": "heat_NE",
                            "can_retire": true,
                            "can_expand": false,
                            "existing_capacity": 6000.0,
                            "investment_cost": 0.0,
                            "fixed_om_cost": 8200,
                            "variable_om_cost": 4.7,
                            "capacity_size": 120.0,
                        },
                        "fuel_edge": {
                            "start_vertex": "natgas_NE"
                        }
                    }
                },
                {
                    "id": "SE_natural_gas_heating_1",
                    "transforms": {
                        "emission_rate": 0.181048235160161,
                        "fuel_consumption": 1.75
                    },
                    "edges": {
                        "heat_edge": {
                            "end_vertex": "heat_SE",
                            "can_retire": true,
                            "can_expand": false,
                            "existing_capacity": 25000.0,
                            "investment_cost": 0.0,
                            "fixed_om_cost": 7000,
                            "variable_om_cost": 3.9,
                            "capacity_size": 500.0,
                        },
                        "fuel_edge": {
                            "start_vertex": "natgas_SE"
                        }
                    }
                }
            ]
        }
    ]
}

Key Points

• The global_data field is utilized to define attributes and constraints that apply universally to all instances of a particular asset type.
• The start_vertex and end_vertex fields indicate the nodes to which the edges are connected. These nodes must be defined in the nodes.json file.
• By default, only the heat edge is allowed to expand as a modeling decision (see note below)
• The heat edge can have unit commitment operations enabled by setting the uc attribute to true.
• For a comprehensive list of attributes that can be configured for the transformation and edge components, refer to the transformation and edges pages of the Macro manual.