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Thermal Model of a House

This demo illustrates how you can use Simulink to create the thermal model of a house. This system

models the outdoor environment, the thermal characteristics of the house, and the house heating

system.

The sldemo_househeat_data.m file initializes data in the model workspace. To make changes, you can

edit the model workspace directly or edit the m-file and re-load the model workspace. To view the model

workspace, select View > odel !"plorer from the Simulink editor.

Contents

#pening the odel

odel $nitialization

odel %omponents

&unning the Simulation and Visualizing the &esults

%losing the odel

&emarks

Opening the Model

$n the 'T(') window, load the model *y e"ecuting the following code +select the code and press to

evaluate selection.

mdl='sldemo_househeat';

open_system(mdl);

Figure 1:The /ouse /eating odel

Model Initialization

This model calculates heating costs for a generic house. 0hen the model is opened, it loads the

information a*out the house from the sldemo_househeat_data.m file. The -file does the following1

2efines the house geometry +size, num*er of windows

Specifies the thermal properties of house materials

%alculates the thermal resistance of the house

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3rovides the heater characteristics +temperature of the hot air, flow-rate

2efines the cost of electricity +4.456k0hr

Specifies the initial room temperature +74 deg. %elsius 8 9: deg. ahrenheit

Note:Time is given in units of hours. %ertain ;uantities, like air flow-rate, are e"pressed per

hour +not per second.

Model Components

Set Point

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open_system([mdl,'/Heater']);

Figure ": The Heater Su#s$stem

Cost Cal%ulator

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open_system([mdl,'/House']);

Figure &:The /ouse Su*system

Modeling the n'ironment

0e model the environment as a heat sink with infinite heat capacity and time varying temperature Tout.

The constant *lock

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'ccording to this model, it would cost around 5@4 to heat the house for two days. Try varying the

parameters and o*serve the system response.

Closing the Model

close_system(mdl);

(emar+s

This particular model is designed to calculate the heating costs only. $f the temperature of the outside air

is higher than the room temperature, the room temperature will e"ceed the desired