MultipleInputSink nodes are [Sink](@extref EnergyModelsBase.Sink) nodes that allow the use of multiple energy carriers (resources) to satisfy a single demand.
Each input resource has a conversion factor, and their combined contribution must meet the demand.
The MultipleInputSink node extends the [Sink](@extref EnergyModelsBase.Sink) functionality to support multiple simultaneous energy inputs with equivalent service delivery. This is useful for modeling technologies such as hybrid heating systems or multi-fuel industrial boilers.
The fields of a MultipleInputSink node are given as:
id:
The fieldidis only used for providing a name to the node.cap::TimeProfile:
The installed capacity corresponds to the nominal demand of the node.
If the node should contain investments through the application ofEnergyModelsInvestments, it is important to note that you can only useFixedProfileorStrategicProfilefor the capacity, but notRepresentativeProfileorOperationalProfile. In addition, all values have to be non-negative.penalty::Dict{Symbol,<:TimeProfile}:
The penalty dictionary is used for providing penalties for soft constraints to allow for both over and under delivering the demand.
It must include the fields:surplusand:deficit. In addition, it is crucial that the sum of both values is larger than 0 to avoid an unconstrained model.input::Dict{<:Resource,<:Real}:
The fieldinputincludes [Resource](@extref EnergyModelsBase.Resource)s with their corresponding conversion factors as dictionaries.
All values have to be non-negative.data::Vector{Data}:
An entry for providing additional data to the model. In the current version, it is used for both providingEmissionsDataand additional investment data whenEnergyModelsInvestmentsis used. !!! note "Included constructor" The fielddatais not required as we include a constructor when the value is excluded. !!! danger "UsingCaptureData" As aSinknode does not have any output, it is not possible to utilize [CaptureData](@extref EnergyModelsBase.CaptureData). If you still plan to specify it, you will receive an error in the model building.
In the following mathematical equations, we use the name for variables and functions used in the model. Variables are in general represented as
\texttt{var\_example}[index_1, index_2]
with square brackets, while functions are represented as
func\_example(index_1, index_2)
with parantheses.
The MultipleInputSink nodes utilize all standard variables from a Sink node, as described on the page [Optimization variables](@extref EnergyModelsBase man-opt_var).
The variables include:
- [
\texttt{opex\_var}](@extref EnergyModelsBase man-opt_var-opex) - [
\texttt{opex\_fixed}](@extref EnergyModelsBase man-opt_var-opex) - [
\texttt{cap\_use}](@extref EnergyModelsBase man-opt_var-cap) - [
\texttt{cap\_inst}](@extref EnergyModelsBase man-opt_var-cap) - [
\texttt{flow\_out}](@extref EnergyModelsBase man-opt_var-flow) - [
\texttt{sink\_surplus}](@extref EnergyModelsBase man-opt_var-sink) - [
\texttt{sink\_deficit}](@extref EnergyModelsBase man-opt_var-sink) - [
\texttt{emissions\_node}](@extref EnergyModelsBase man-opt_var-emissions) ifEmissionsDatais added to the fielddata
It does not add any additional variables.
The following sections omit the direct inclusion of the vector of MultipleInputSink nodes.
Instead, it is implicitly assumed that the constraints are valid \forall n ∈ N for all MultipleInputSink types if not stated differently.
In addition, all constraints are valid \forall t \in T (that is in all operational periods) or \forall t_{inv} \in T^{Inv} (that is in all investment periods).
MultipleInputSink utilize in general the standard constraints that are implemented for a [Sink](@extref EnergyModelsBase nodes-sink) node as described in the [documentation of EnergyModelsBase](@extref EnergyModelsBase nodes-sink-math-con).
These standard constraints are:
-
constraints_capacity:$$\texttt{cap\_use}[n, t] + \texttt{sink\_deficit}[n, t] = \texttt{cap\_inst}[n, t] + \texttt{sink\_surplus}[n, t]$$ -
constraints_capacity_installed:$$\texttt{cap\_inst}[n, t] = capacity(n, t)$$ !!! tip "Using investments" The function
constraints_capacity_installedis also used inEnergyModelsInvestmentsto incorporate the potential for investment. Nodes with investments are then no longer constrained by the parameter capacity. -
constraints_opex_fixed:
The current implementation fixes the fixed operating expenses of a sink to 0.$$\texttt{opex\_fixed}[n, t_{inv}] = 0$$ -
constraints_opex_var:$$\begin{aligned} \texttt{opex\_var}[n, t_{inv}] = & \\\ \sum_{t \in t_{inv}} & surplus\_penalty(n, t) \times \texttt{sink\_surplus}[n, t] + \\ & deficit\_penalty(n, t) \times \texttt{sink\_deficit}[n, t] \times \\ & scale\_op\_sp(t_{inv}, t) \end{aligned}$$ !!! tip "The function
scale_op_sp" The function [scale\_op\_sp(t_{inv}, t)](@extref EnergyModelsBase.scale_op_sp) calculates the scaling factor between operational and investment periods. It also takes into account potential operational scenarios and their probability as well as representative periods. -
constraints_data:
This function is only called for specified additional data, see above.
The function constraints_flow_in receives a new method to account for that the individual resources can be used interchangeably adjusted by their specific conversion factor:
The total effective input from all resources (accounting for their conversion factors) must equal the capacity used to meet demand.
!!! tip "Conversion factors"
The input resource values in \texttt{flow\_in} are divided by their conversion factors to normalize their contribution toward demand fulfillment.