A Substitutive Coefficients Network for the Modelling of Thermal Systems: A Mono-Zone Building Case Study

Lahoucine Ouhsaine,Jean-Michel Nunzi,Abdelaziz Mimet,Mohammed El Ganaoui

doi:10.3390/en14092551

Abstract

A modelling approach based on the Substitutive Coefficients Network (SCN) is developed to predict the thermal behavior of a system in the dynamic state-space, without requiring knowledge of the thermal mass. The method can apply either to large- (building, combined solar systems, geothermal energy, and thermodynamic installations) or to small-scale systems (heat exchangers, electronic devices cooling systems, and Li-ion batteries). This current method is based on a dimensionless formulation of the simplified dynamic thermal balance model, using relaxation time as a key parameter to establish the model. The introduction of relaxation time reduces the parameters set as guidance coefficients. The parameters are finally expressed by a combination of global heat transfer coefficients related to each layer and/or sub-layer of the system. Advantages of the method are reliability, “non-destructibility”, i.e., it allows a reliable prediction of the thermal behavior which experimentally is inaccessible, and reducibility of the parameters size estimate. Additionally, the method is inexpensive in terms of computation memory. It is also easy to implement in practical numerical schemes. In this paper, the method leads to a simplified mathematical model that predicts the thermal behavior of a mono-zone eco-cottage building installed at Lorraine University (in Longwy, France) as a case study. Thermal performance of the building is estimated under the hourly weather conditions onsite, as obtained from the Meteonorm software. The thermal dynamics within hourly Typical Meteorological Year 2 (TMY2) Meteonorm data disturbances and the internal heating input state in the winter period were simulated with a simplified numerical discretization method. Results provide a general dynamic state of the different sub-components of the system, with limited design of the model parameters.

Highlights

Substitutive Coefficients Network (SCN) offers a practical approach to reduce the estimation of the parameter set in the thermal model, especially the heat capacity, and to surrogate it with a relaxation time which can be measured in real cases. We present this novel approach, highlighting the importance of the relaxation time to adjust the model
We clearly observe from the above figures that the behavior of the thermal simulationThis fits proportionally the an external disturbances andSCN
The obtained dynamic results plained by the heat transfer coefficient which is

Summary

Introduction

The evolution of thermal energy systems is a subject of major importance today. It is considered a very complex problem in terms of geometry and sub-system coupling methods. The aim is to enhance the efficiency and thermal performances of thermal processes. Several methods were used to model and to better simulate the thermal behavior. The technique of simplified or “reduced-order models” gets a special attention as it performs better for temperature estimation

Objectives

Results

Conclusion