Thermai simulation using thermal networks method for simple buildings

مقدم أطروحة جامعية

Muslim, Adil Khalaf

الجامعة

الجامعة التكنولوجية

الكلية

-

القسم الأكاديمي

قسم الهندسة الكهربائية

دولة الجامعة

العراق

الدرجة العلمية

ماجستير

تاريخ الدرجة العلمية

2006

الملخص الإنجليزي

This study focuses on a mathematical model applied to a room, which may be part of a building in Baghdad at a typical hot day on the 30th of August.

Lumped capacities and thermal resistances of the building elements had summarized by analogue of an electric circuit i.e., the room is represented by a thermal network.

The parameters in a room thermal simulation model have been tracked and the calculations were based upon the heat balance every hour.

Most of building simulation analysis use one-hour time step since weather files normally give hourly values.

A set of simultaneous equations attained and treated in a fully implicit scheme.

MATLAB has been used to simulate thermodynamic models and building thermal performance a nalysis.

In order to reduce the influence of initial conditions, MATLAB program has been submitted to three pre-simulations (warm-up) for the same day of 30lh of August with constant initial temperature.

The model has been studied with varying input (wall thickness, thermal capacity, window influence, etc.) and the output has been given as an indoor temperature, inside surfaces temperature and outside surfaces temperature, as well as heat flow flux in the walls.

The walls and roof of the room model were exposed to the outdoors.

In order to study the effect of room elements on indoor temperature only, the room is assumed to be without furniture, people or any supplementary heat.

When tracking the effect of wall type and its construction on indoor temperature, all other elements of the room, such as roof and floor constructions, window size etc.

are regarded to be fixed.

The room is assumed to be without ventilation unless mentioned.

As a result, important conclusions have been drawn indicating that thermal networks method allows dynamic modeling of a building and solution of complicated problems since any building can be modeled by analogy with an electric circuit.

Regarding to the influence of a building envelope, the study has indicated that the use of high thermal mass building materials delays the transmission of heat to the building until the outdoor temperature and solar radiation reach their lowest values.

In addition, thermal mass loses effectiveness as insulation position shifts from the exterior to the interior of a building envelope.

An air cavity within building envelope gives the same effect on thermal performance of a building as the insulation materials, but with less efficiency.

Moreover, the influence of windows and their sha ding devices, colors of outside surfaces and suspending ceilings have been studied.

It was drawn that, orientation, area and shading device of a window must be carefully selected.

Shading or treatment of outside surface of a building envelope by light colo rs is more effective in reducing the absorption of solar radiation than normal measures to increase thermal capacity or thermal resistance.

As a regard to suspending ceiling, it reduces the mean daily indoor temperature and improves the capability of roof to block off heat penetration.

التخصصات الرئيسية

الهندسة المدنية

الموضوعات

• النماذج الرياضية
• العراق

• APA
• MLA
• AMA

لغة النص

الإنجليزية

نوع البيانات

رسائل جامعية

رقم السجل

BIM-305602