Generic Thermal Model of Electric Appliances
Integrated in Low Energy Building
Herie PARKa,c,*, Marie Ruellan", Nadia Martaj
b
, Rachid Bennacer
b
and Eric Monmassona
aSATIE CNRS UMR8026, University of Cergy-Pontoise, Cergy-Pontoise, France
b
LMT CNRS UMR 8535, Ecole Nomale Superieure de Cachan, Cachan, France
cDep. of electrical engineering, Yeungnam University, Gyeongsan, Gyeongbuk, Korea
(herie.park, marie.ruellan, eric.monmasson)@u-cergy.r, nadia _ martaj@yahoo.r, rachid.bennacer@dgc.ens-cachan.r
Abstract-This paper presents a generic thermal model of electric
appliances as an auxiliary heat source in low energy
consumption buildings. The electric appliances are irstly
classiied into four categories by their heat and mass transfers.
The mathematical model and its electric equivalent circuit are
proposed based on the irst law of thermodynamics and the
thermal-electric analogy. Then the correspondence between the
proposed model and the ARX model is presented for a
parametric identiication. To illustrate this study, two electric
appliances of the closed-heating category, a monitor and a
refrigerator, are selected. Each model has been experimentally
tested and identiied in a well-insulated building. They are
implemented in a simple RC-Iumped building model and
simulated using Matlab/Simulink. Both experimental data and
simulation results are compared.
I. INTRODUCTION
Nowadays, the concept of low energy buildings is focused
on achieving low environmental impacts of buildings. It is
especially related to the amounts of energy consumption and
of CO2 emission. In order to reduce the environmental
impacts and realize high energy eiciency of buildings, many
countries strengthen their building regulations and codes. In
addition, many researchers have also worked on analyzing the
energy performance of buildings and integrating the
renewable energy technologies into buildings [1].
In the ield of building, the energy is used for space
heating/cooling, lighting, equipment/appliances operating and
water heating. The energy demands for heating and cooling
system are more than a third of the energy used in both of
residential and non-residential (or commercial) buildings [2].
These demands depend on the exterior characteristics of
buildings, the physical properties as well as the types, and the
energy eficiencies of inner sub-systems of buildings.
Therefore, the themal analysis of buildings based on this
infomation is important to assess the building energy
performance. Furthermore, the analysis pemits to predict
thermal responses, design sub-systems, calculate
heating/cooling loads, and conrol these sub-systems of
buildings. It is helpul to achieve the energy eiciency and
the thermal comfort of buildings.
During the past few decades, building energy simulation
tools have developed for such a thermal analysis. The most
representative simulation tools of them are ESP-r, TRNSYS,
EnergyPlus, SPARK and SIMBAD. These are based on
undamental laws of energy, heat and mass transfer [3-4].
With the help of the validated building simulation tools,
energy performance of a building could be evaluated during
its life cycle. It is obvious that the results of the evaluation
differ rom building components.
Among the components, there are intenal heat gains
caused by solar irradiation, operations of electric appliances
and occupant's behavior in a building. These gains have been
taken into account for the heating/cooling loads calculation.
In low energy building, which thermal insulation is reinforced,
the intenal heat gains become decisive factors on the
building energy consumption and the thermal comfort of
occupants. However, because of their uncertainties it is not
easy to predict the gains. Thus, ahnost of the simulation tools
have been used the past weather information and the pre
detemined proiles of electric load usages and the occupancy.
These uncertainties of heat gains have been caused retroit
errors between the simulation and the validation of energy
analysis of buildings [5-6].
Moreover, as more reliable results and accuracies are
expected, the simulation time interval tends to be shorter than
an hour. In intra-hour simulations, the models of a building
and its sub-systems have to be more accurate in order to catch
the highest dynamics. Even though many researchers have
worked on solar irradiation models [7-8], both deterministic
and stochastic models of occupant's behavior and lighting
usages [9-10], metabolic heat gains by occupants [11] in
buildings, there are only a few works on the modeling of heat
gain of electric appliances [12-13].
Therefore, the objective of this paper is to propose a
generic thermal model of electric appliances. It is especially
applied in low energy consumption buildings. It permits to
calculate the temporal heat gain of electric appliances and
predict the indoor temperature of the building. For this, we
irstly classiy electric appliances regarding their power
characteristics. In section III the generic model are introduced
based on the irst law of thermodynamics and the thermal
electric analogy. A parametric identiication method of the
proposed model using ARX model is presented. In section IV
the proposed model is applied to two actual cases: a monitor
and a rerigerator. Then the parameterized models are
integrated in a simple building model implemented on
Matlab/Simulink. Simulated temperature evolutions and heat
lux of each model are compared to measured experimental
results. The last section concludes the work.
978-1-4673-2421-2/12/$31.00 ©2012 IEEE 3318