Models
This page gives an overview of the available models in SIMONA.
Model 
Description 

Combined heat and power plant 

Wind energy converter 

Electric Vehicle Charging Station 
ChpModel
This page documents the functionality of the CHP Model (combined heat and power plant model) available in SIMONA. This model is part of the SIMONA simulation framework and represented by an agent. The current model is feasible to simulate nano and microCHP units. As it is a crosssector agent (heat/electricity) the usage of a househeatmodel is mandatory.
Attributes, Units and Remarks
Attribute 
Unit 
Remarks 

uuid 
– 
universally unique identifier 
id 
– 
human readable identifier 
operationInterval 
– 
time interval, in which the system is operating 
scalingFactor 
– 
scaling the output of the system 
qControl 
– 
type of reactive power control 
sRated 
kVA 
rated apparent power 
cosPhiRated 
– 
rated power factor 
pThermal 
kW 
rated thermal power (generated by CHP unit) 
storage 
– 
thermal storage 
Implemented Behaviour
 Assumptions
The CHP unit is able to operate either at full load or not at all. Uncovered heat demand of former time steps is not considered in the following steps, as the CHP unit does not posses a memory.
 Agent Objectives
The objective of the CHP agent is to cover the given heat demand in each timestep.
 Storage medium
This model can be implemented with any mutable storage (meaning that the storage requires the trait MutableStorage). The CHP unit is able to store/take energy, while the underlying storage medium performs the calculations for these operation.
The implemented behaviour is shown in the program sequence plan below. In general, the unit will turn on, if the energy in the storage is too low to satisfy the given heat demand and will turn off if the storage is completely filled. During operation, the CHP unit operates at full utilization.
Implementation:
 Mathematical concept
The implementation of the CHP unit’s behavior is based on the following mathematical model.
Variable
Remarks
c(t)
indicates if the CHP unit is running or not
I
interval of two time steps (t1, t]
td(t)
time of a single time step
WD(t)
heat demand
Wchp,n(t)
rated heat production
Wst(t)
storage level of the storage medium given by energy
Wst,min
minimum storage level of the storage medium given by energy
Wst,max
maximum storage level of the storage medium given by energy
Wges(t)
Wchp,n(t) + Wst(t)
deltaWD(t)
WD(t)  Wchp,n(t)
Qth,chp,n(t)
rated heat flow produced by the CHP
Pchp,n(t)
rated active power production
Pgen(t)
generated active power
Qgen(t)
generated reactive power
Given a time interval I, the heat demand WD(t1), the running status c(t1) and the storage energy level Wst(t1) the CHP model calculates if the heat demand can be covered and if the CHP unit has to be turned off/on.
WecModel
This page describes the wind energy converter model (WecModel). Given the current wind velocity, temperature and air pressure the model can calculate the wind turbines active power output.
Attributes, Units and Remarks
Attribute 
Unit 
Remarks 

uuid 
– 
universally unique identifier 
id 
– 
human readable identifier 
operationInterval 
– 
time interval, in which the system is operating 
scalingFactor 
– 
scaling the output of the system 
qControl 
– 
type of reactive power control 
sRated 
kVA 
rated apparent power 
cosPhiRated 
– 
rated power factor 
rotorArea 
m² 
the swept area of the turbines rotor 
betzCurve 
– 
see example below (Enercon E82) 
Calculation
The figure below depicts the calculation steps as implemented.
 Air density
The air density is calculated using the temperature and the air pressure, as stated in the diagram above. For this calculation the formula ρ = (P * M) / (R * T) is used. The arguments for this formula are listed in the table below. In case no air pressure is given, the default value 1.2401 kg/m³ is returned, which corresponds to the air density at sea level at 20° Celsius.
Argument 
Unit 
Remarks 

P 
Pa 
air pressure 
M 
kg/mol 
molar mass of air (0.0289647) 
R 
J/(mol*K) 
universal gas constant (8.3144626181532) 
T 
K 
temperature 
Note, that the arguments M and R are constants. Their values are contained in the column “Remarks”. After inserting the constant values the formula looks as follows: ρ = P / (287.058 * T)
Enercon E82
It is useful to look at a real wind turbine for the visualization of some parameters.
 Rotor area
The Enercon E82 has a threebladed rotor with a diameter of 82m. A rotors swept area is a circle, therefore it is calculated as follows: A = π * r². The swept area (rotorArea) of the Enercon E82 is 5281.02 m² = π * (82m / 2)².
 Betz curve
The betz curve (or betz characteristic) is a mapping of wind velocities to cP values. It is used to determine the power that can be extracted from the wind. It follows Betz’s law. Each wind turbine has a unique betz curve. The figure below shows the betz curve for the Enercon E82 wind turbine.
The cutin wind velocity is 2 m/s, meaning that the turbine requires wind speed of at least 2 m/s to produce energy. The cutoff wind velocity is 34m/s, meaning that the Enercon E82 won’t produce energy for velocities that are higher.
EvcsModel
The currently connected EvModels are saved within the state data of EvCsAgent and passed to EvCsModel with each trigger. The model then calculates the active load of the charging station.
Attributes, Units and Remarks
Attribute 
Unit 
Remarks 

uuid 
– 
universally unique identifier 
id 
– 
human readable identifier 
operationInterval 
– 
time interval, in which the system is operating 
scalingFactor 
– 
scaling the output of the system 
qControl 
– 
type of reactive power control 
sRated 
kVA 
rated apparent power 
cosPhiRated 
– 
rated power factor 
chargingPoints 
– 
number of charging points available 
locationType 
– 
the charging station location type 
Calculation
The following arguments need to be provided for power calculation:
Argument 
Unit 
Remarks 

dataFrameLength 
– 
duration in ticks until next EV movement data 
currentEVs 
– 
set of EVs connected to the CS at this moment 