modelBoiler

Information

It is a dynamic model of modulating condensing boiler.

Hypothesis and equations

The gas consumption prediction model is estimated with a grey box model. Electric consumption is determined according to the consumption of the various operation phases of the boiler (purging, pump, power on/off, standby, etc).

This model requires a limited amount of input data accessible from the normative tests.

Following a sensitivity analysis,

• The durations of anti-short cycles (abnormally rapid start and stop cycles), and especially the duration of the pump operation after combustion have a very significant impact on consumption and the number of machine cycles;
• The parameter Δη (representing the decrease in performance depending on the load at a return of water temperature equal to 30°C) has nearly no effects on the results for the temperature levels of the water law in question (between 35 and 45°C). In the case of modelling a system requiring water temperatures higher than 35°C, the user can leave the default value, especially since this parameter is not provided in the ATITA basis;
• Consideration of pre-combustion purge, during which the air in combustion chamber must be renewed, has also a reduced impact: over-consumption does not exceed 0.5% and is more due to a 30 second delay before launching the boiler than to the thermal power lost in the smoke.

Bibliography

The model is configurable from certified data accessible in the ATITA basis (rt2012-chauffage.com).

Instructions for use

none

Known limits / Use precautions

This is a detailed dynamic model. Some phenomena are represented in a simple way:

• Heat losses through the wall are fully transmitted to the environment (RT2012 gives the lost part coefficients -for example through the wall for a wall boiler)
• The consumption of auxiliary is partially degraded in thermal form (e.g. via the conversion of the water kinetic energy in pipes into heat by friction for the power supplied to the pump), this energy conservation is not considered now

Validations

Validated model - Hubert Blervaque, Sila Filfli 07/2013

--------------------------------------------------------------
Licensed by EDF under a 3-clause BSD-license
Copyright © EDF 2009 - 2023
BuildSysPro version 3.6.0
Author : Hubert BLERVAQUE, Sila FILFLI, EDF (2013)
--------------------------------------------------------------

Parameters

Connectors

Components

Revisions

Benoît Charrier 05/2015 : Suppression des connecteurs T & m_flow.

Benoît Charrier 01/2016 : Passage du calcul du débit en equation pour compatibilité OpenModelica.