pipe heat exchanger
A heat pipe is a sealed self-contained, liquid evaporating
condensing system, usually shaped like a cylinder. Heat
is transferred from the hot incoming gas to the evaporator
section of the heat pipe. The local vapour pressure increases
and evaporated fluid flows along the pipe to the condenser
section. The vapour pressure is lower here, so the liquid
condenses and the heat is released to the cold gas. The
liquid then returns to the evaporator by a combination of
capillary action and gravity.
No energy input is required to operate the
Heat Pipes. When two air streams pass through the Heat Pipes,
(one air stream at one end, and another air stream at the
other end), the temperature difference between the two air
streams activates the Heat Pipes and causes them to exchange
heat by “Heat Pipe action”. Heat Pipe action
is a much more powerful heat transfer mechanism than convection
flow. Heat Pipe action utilizes the heat capacity available
when the working fluid changes phases, from a liquid to
a vapor and back again.
There is nothing in the Heat Pipes to wear
out! The Heat Pipes are passive. They have no moving parts
(unless they come equipped with a bypass damper.) To guard
against corrosion, the Heat Pipes can be ordered with a
baked epoxy coating or other protective coating. The Heat
Pipes are fabricated with a multitude of charged circuits.
Under normal operations, there is no reason for these ever
to leak. If some inadvertent mechanical damage were to occur
on one circuit to cause it to leak, there would be little
effect on performance even if the leak was not repaired.
Furthermore, because the tubes in Heat Pipe Technology Heat
Pipes are copper, leaks can be fixed. Most other Heat Recovery
Heat Pipes are fabricated with aluminum tubes which are
very difficult to repair.
Isolated Air Streams
Dividing plates to separate the two air streams
are an integral part of Heat Pipe Technology Heat Recovery
Heat Pipes. The copper tubes carrying the Heat Pipe working
fluid are expanded into the mating holes in the dividing
plates, assuring an excellent seal to prevent cross contamination.
Since the Heat Pipes have no moving parts
(apart from any dampers), the only maintenance recommended
is periodic cleaning. A coil cleaner may be applied for
this purpose just as for any cooling coil.
Heat Recovery Heat Pipes from Heat Pipe Technology
take up much less space than other heat recovery schemes.
They are also generally considerably thinner than other
heat pipes. A six-row Heat Recovery Heat Pipe can be fabricated
with a thickness of as little as 7 inches.
Summer and Winter
The same Heat Pipe can be used for both summer
cooling and winter heat recovery without any changeover
mechanism. The temperature difference between the air streams
activates the energy recovery.