Transcript File - Gray Cooling Man Air Conditioning Repair Advice

Introduction to heat
• Is this heat?
• When I touch it, it
burns me.
• I can feel the heat at
a distance
• The hot gases rise
But is this heat?
• Yes
• The difference
between the two is
Temperature
Any substance whose
temperature is above
-276 degrees celsuis
or -460 degrees
Fahrenheit contains
heat
Whether something is hot or cold
is subject to your preconceived
experience
• When we see blue we
tend to think cold
• When we see red we
tend to think hot
HVAC and R
• H is for heating
• V is for ventilation
• AC is for air conditioning or
cooling
• R is for refrigeration
Heating
• Increasing temperature from an intensity
that is felt as too low to a comfortable
intensity
• This can be accomplished by combustion
of a chemical that releases heat
• Moving of heat from one place to another
• Convincing the person that they are
actually warm
Ventilation
• The movement of air to distribute heat
Air Conditioning
• This is a little more complicated
• Air conditioned air is generally considered
cooled air.
• Its humidity is also changed when it is
cooled so it is considered conditioned
Refrigeration
• Refrigeration is generally considered as
temperatures below human comfort
• First used to extend perishable food life
Heating Technology
• Technologically, heating is far easier than
cooling
• The first forms were wood fired campfires
around which everyone sat to be warmed
Advantages
• Easy to start if you had something hot and
it had not rained lately
• Fuel was easy to find
• Fire looks cool
Disadvantages
• Was not self sustaining
• Smoke always followed you wherever you
sat
• Rain had a dampening effect
• You were always cold on the side opposite
the fire
Ways to make campfire better
• Place fire in some sort of shelter to contain
heat
A better system with fire in center
and way for smoke to leave
An even better way
But how effective is a fireplace?
Can you effectively heat a structure
with a fireplace?
• No
• Any ideas why?
The fireplace draws air from the
structure in large amounts
If you draw large
amounts of air from a
structure, it must be
replaced by outside
air
Where do you think the
air comes from?
It must be drawn in
from cracks in windows
and doors
And what temperature
is this air?
The same temperature as the
outside air which is why the
other rooms in the structure are
very cold after the fire has been
burning for a while
So what can be done to
solve this problem?
The Franklin Stove
The Franklin Stove (invented by
Ben Franklin) covered the
majority of the open area that
removed so much air and only
allowed enough air to support
combustion
The cast iron body of the stove
was warmed by the fire which
warmed the air in the room
We have developed a stove that
is reasonably efficient that can
heat a structure. Is this the best
system for heating?
What if there are more than one
room in the house?
• The temperature in the room with the
stove will be warm
• All other rooms will be progressively cooler
the farther they are from the heat source
This is a typical modern
ductwork layout system
Heat travels from the furnace
Forced by a fan through the
Supply ducts to the
Conditioned space
Return air travels
Through the return
Ducts to the furnace