.TransiEnt.Producer.Heat.Gas2Heat.SmallGasBoiler.Gasboiler_dynamic_L1

Information

1. Purpose of model

Simple dynamic gas boiler model with splitted heat generation and emission (CO2) calculation

2. Level of detail, physical effects considered, and physical insight

By default, a given heat duty Q_flow,set is set (limited) to the boilers characteristica (Q_flow,n, Q_flow,min) and then set to a static ideal heat exchanger. For the given heat carrier supply temperature the required heat carrier mass flow is calulated. For the operational mode the supply temperature can also be left variable.

In hold-temperature-mode the boiler needs no heat flow set-input and will heat the carrier to the given temperature within its limits of power. The Q_flow,set-value is therefore calculated within the model. In this mode, the boiler can also operate with staged power (on/off or full/part/off), where the power percentage at the part-stage can be given.

The boiler's dynamic is modelled signal based with a first order delay which is variable with the power change step size so that smaller duty changes can be served faster.

From the part load of the boiler and the return flow temperature, the boiler efficiency and fuel heat input is calculated with characteristical lines.

Depending on the users preference (set by the parameter referenceNCV), efficiencies and power calculations in this model are based on either the net or the gross calorific value (NCV or GCV, respectively). With a function for dynamic HV calculation the required fuel mass flow as an output-value is generated.

3. Limits of validity

A constant air ratio to be chosen is asumed.

4. Interfaces

Q_flow_set_internal - heat duty input (only in default mode)

T_supply_set_internal - temperature input in K

gasPortIn/Out - port for fuelgas at the inlet and exhaustgas at the outlet

waterPortIn/Out - ports for the heat carrier (water)

m_flow_fuel_req - output of required fuel mass flow rate

m_flow_HC - output of heat carrier mass flow rate

5. Nomenclature

6. Governing Equations

(no remarks)

7. Remarks for Usage

(no elements)

8. Validation

(no validation or testing necessary)

9. References

(no remarks)

10. Version History

Model created by Paul Kernstock (paul.kernstock@tu-harburg.de) July 2015

Revised by Lisa Andresen (andresen@tuhh.de), Aug 2015