modelHeatSource_CondensingGasBurner
Information
Description
This model is based on data from a Remeha boiler. It is used in the Boiler model.
The nominal power of the original boiler is 10.1 kW at 50/30 degC water temperatures. The efficiency in this point is 92.2% on higher heating value.
First, the efficiency is interpolated for the return water temperature and flowrate at 5 different modulation levels. These modulation levels are the FUEL input power to the boiler. The results are rescaled to the nominal power of the modelled heatpump (with QNom/QNom_data) and stored in a vector, eta_vector.
Finally, the initial modulation is calculated based on the asked power and the max power at operating conditions:
- if modulation_init < modulation_min, the boiler is OFF, modulation = 0.
- if modulation_init > 100%, the modulation is 100%
- if modulation_init between modulation_min and modulation_start: hysteresis for on/off cycling.
If the boiler is on another modulation, interpolation is made to get eta at the real modulation.
ATTENTION
This model takes into account environmental heat losses of the boiler. In order to keep the same nominal eta's during operation, these heat losses are added to the computed power. Therefore, the heat losses are only really 'losses' when the boiler is NOT operating.
The eta is calculated as the heat delivered to the heatedFluid divided by the fuel consumption PFuel.
Assumptions and limitations
- Based on interpolation in manufacturer data for Remeha condensing gas boiler
Model use
This model is used in the Boiler model. If a different gas boiler is to be simulated, copy this Burner model and adapt the interpolation tables.
Validation
See the Boiler model.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Real | modVector | {0, 20, 40, 60, 80, 100} | 6 modulation steps, % |
| Modelica.Units.SI.ThermalConductance | UALoss | UA of heat losses of HP to environment | |
| Modelica.Units.SI.Power | QNom | The power at nominal conditions | |
| Modelica.Units.SI.Power | QNom0 | 10100 | Nominal power of the boiler from which the power data are used in this model |
| Real | etaNom | 0.922 | Nominal efficiency (higher heating value)of the xxx boiler at 50/30degC. See datafile |
| Real | modulationMin | 10 | Minimal modulation percentage |
| Real | modulationStart | 20 | Min estimated modulation level required for start of HP |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a | heatPort | heatPort connection to water in condensor |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Real | eta | Instantaneous efficiency of the boiler (higher heating value) | |
| Real | etaVector | Thermal efficiency (higher heating value) for 6 modulation steps, base 1 | |
| Real | QVector | Thermal power for 6 modulation steps, in kW | |
| Modelica.Units.SI.Power | QMax | Maximum thermal power at specified evap and condr temperatures, in W | |
| Modelica.Units.SI.Power | QAsked | ||
| Real | modulationInit | Initial modulation, decides on start/stop of the boiler | |
| Real | modulation | Current modulation percentage | |
| Modelica.Units.SI.Power | PFuel | Resulting fuel consumption | |
| Modelica.Units.SI.Temperature | THxIn | Condensor temperature | |
| Modelica.Units.SI.Temperature | TBoilerSet | Condensor setpoint temperature. Not always possible to reach it | |
| Modelica.Units.SI.MassFlowRate | m_flowHx | Condensor mass flow rate | |
| Modelica.Units.SI.Temperature | TEnvironment | Temperature of environment for heat losses | |
| Modelica.Units.SI.SpecificEnthalpy | hIn | Specific enthalpy at the inlet | |
| Controls.Discrete.HysteresisRelease | onOff | ||
| Modelica.Blocks.Sources.RealExpression | realExpression |
Contents
| Name | Description |
|---|---|
 Medium | Medium in the component |
Revisions
- 2014 May, Damien Picard: change Modelica.Math.Interpolate to IDEAS.Utilities.Math.Functions.cubicHermiteLinearExtrapolation in order to remove non-differentiable equations
- 2014 May, Damien Picard: correct bug introduced during conversion to Annex on the QAsked
- 2013 May, Roel De Coninck: documentation
- 2011 August, Roel De Coninck: first version