1. THERMODYNAMIC

2. Contents
Introduction
Thermal Transfer Theory
Psychometric and Process

3. INTRODUCTION What is Thermodynamic?
Thermodynamic is a science dealing with the relationship between heat and other forms of energy. It includes the subjects of heat transfer and psychometrics (atmospheric condition)

5. INTRODUCTION Understanding the thermal space.
Important of thermodynamic knowledge:
Understanding the thermal space.
Understanding the mechanism of the thermal interaction of the building interior with surrounding.
Identification of the mechanical heating and cooling equipment.

6. INTRODUCTION
Important of thermodynamic knowledge:
Understanding the heat flow characteristics such as ability to control heat gain and lost (construction, orientation, particular building materials).
Understanding the cost of heating and cooling expenses and how to save energy bills.

7. THERMAL TRANSFER THEORY
The flow of heat/thermal is defined as energy transfer between two regions due to a difference in temperature.
Heat transfer is actually the transfer of energy on a microscopic scale.
Heat transfer is the transfer of motion from a more excited group of molecules to a less excited group.

8. THERMAL TRANSFER THEORY
Heat transfer on a molecular
level. When hot, excited
molecules are blended with
cool, unexcited molecules;
the result is a level of
molecular excitation
(temperature) between the
two extremes.

9. THERMAL TRANSFER THEORY
Cold region – containing less thermal energy.
Warm region – containing more thermal energy.
Temperature difference – tendency for heat to flow from the region with the higher temperature to the lower temperature.

10. THERMAL TRANSFER THEORY
The rate of heat transfer will be a function of:
(1) the magnitude of the temperature difference
(2) the area perpendicular to the heat flow part
(3) the resistance to heat transfer of whatever
medium separates the two areas
Heat transfer path through a medium

11. THERMAL TRANSFER THEORY
CONDUCTION
The three modes of heat transfer

12. THERMAL TRANSFER THEORY
Heat or thermal energy transfer from one region to another occurs by three modes;
CONDUCTION – heat transfer from one particle to another in direct contact with it.
CONVECTION – heat transfer by fluid motion
RADIATION – heat transfer by electromagnetic waves

13. THERMAL TRANSFER THEORY CONDUCTION
Conduction is the heat through solid materials.
Cause by molecules vibrating as a faster rate (higher temperature) bumping into and transferring energy to molecules vibrating at a slower rate (lower temperature).
Transfer occurs when there is a temperature difference across the material.

14. THERMAL TRANSFER THEORY CONDUCTION
Gypsum Drywall
Fiberglass Batt Insulation
Insulative Sheathing
Wood Siding

15. THERMAL TRANSFER THEORY CONVECTION
Convection is thermal energy being carried by the flow of a liquid or gas.
Transport of heat by fluid motion, and is normally associated with the transfer of heat between a surface and a fluid (such as water/air moving across).
Example – room air giving up heat to a window on a cold day and the glass conducts the heat outside.

16. THERMAL TRANSFER THEORY CONVECTION
COOL SIDE
WARM SIDE
Heat transfer through a double-
pane window. Heat convects from
the warm airflow to the first layer
of glass, conducts through the
glass, convects from the first
layer of glass to the second layer,
conducts through the glass, and
then convects into the air stream
on the cool side.
Air Flow Between Layers of Glass
Air Flow
Heat Flow
Air Flow
Doubled – Glazed
Fixed Window

17. THERMAL TRANSFER THEORY RADIATION
The internal energy or molecular vibrations set up electromagnetic waves that emanate from the warm object and carry the energy to all bodies within a direct line of site.
Radiant (from sun) energy can;
(1) reflected from the surface
(2) absorbed by the material
(3) transmitted through

18. RADIATION The electromagnetic spectrum Max. Energy X-Rays Gamma Rays
Ultraviolet Light
Visible Light
Blue, Green, Yellow, Red
Infrared
Surface of Sun
Room Temperature
Microwave
Radar
UHF TV Carrier
VHF TV Carrier
FM Radio Carrier
High Frequency Amateur Radio Bands
AM Radio Carrier

19. Wall Sections

20. Roof Sections Outside surface 3/8” Tar and Gravel Built-up Roofing
3/4” Styrofoam Insulation
3” Concrete Slab
2” Shredded Wood Fiberboard
Steel Joists
16” Air Space
Roof Sections
Furring Channels
2 Layers ½” Gypsum Board
2” Sound Absorbing Materials
Inside Surface

21. PSYCHOMETRICS
Psychometrics is a branch of physics concerned with the study of atmospheric conditions and, in particular, the relationship between air and moisture when mixed together.

22. PSYCHOMETRICS
Psychometric chart

23. PSYCHOMETRICS Air-Conditioning Process
There are basically four processes of thermal air conditioning;
Heating
Cooling
Humidification
Dehumidification

24. PSYCHOMETRICS Air-Conditioning Process
Humidification – normally accompanies heating.
Dehumidification – associated with cooling.