.BuildSysPro.Systems.HVAC.Emission.Radiator.Radiator_EN442

Information

Simple hot water radiator model for central heating system

Hypothesis and equations

This model is based on the characteristic equation (Qflow=Km DT^N) described in the EN442 standard.

Depending on the model options, DT could be considered as followed:

• DT= T_HWR - Troom where Troom = Trad+Tconv/2 if radEqua=BuildSysPro.BaseClasses.HeatTransfer.Components.BasedCharacteristicEquation1
• or 2 characteristic equations could be considered for radiative and convective heat transfers respectively : DTrad= T_HWR - Trad and DTconv= T_HWR - Tconv if radEqua=BuildSysPro.BaseClasses.HeatTransfer.Components.BasedCharacteristicEquation2

Otherwise the model use common equations for energy balance and continuity equation (no mass accumulation).

Depending on the option useInertia, steady state or dynamic behaviour are computed. For dynamic computation, the energy balanced is calculated as :

This model does not considered a discretization along the fluid path.

This model relies also on an arithmetic mean temperature difference (AMTD), different from the theorical logarithmic mean temperature difference (LMTD) and should be used when the following condition is fulfilled :

Otherwise using AMTD leads to a deviation exceeding 10%.

Bibliography

This model was implemented following the EN442 standard and considering a single element.

Nilsson, P.E. and The Commtech Group, 2003. Achieving the Desired Indoor Climate: Energy Efficiency Aspects of System Design. Studentlitteratur AB.

Instructions for use

Connect the model to a distribution network through the WaterIn and WaterOut connectors.

Connect also the model to a thermal ambiance through the Conv and Rad heatports respectively for convective heat transfers and long wave radiation.

Known limits / Use precautions

The model is not discretized along the fluid path therefore in Dynamic mode, nominal operating conditions do not lead to the nominal heating power.

Validations

Simple validation based on operating point - Gilles Plessis 01/2016

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Licensed by EDF under a 3-clause BSD-license
Copyright © EDF 2009 - 2023
BuildSysPro version 3.6.0
Author : Gilles PLESSIS, EDF (2016)
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