7
010.4150.0720 08.21
3. PRE-INSTALLATION INFORMATION
The VHX-DR Heat Recovery Center is used with a liquid in
the circuit with connections and a gas on the open side. The
heat exchanger must operate in line with approved design
parameters: temperatures, pressures and flow rates.
Liquid side
Typical medias are ethylene/propylene glycol, thermal oil,
and water. It is important that the liquid is of good quality
without contamination or corrosive substances. The medias
should not contain particles or any other undissolved matter,
we recommend that a strainer with a size of 16-20 mesh
(number of openings per inch) is installed before the fluid
inlet. The particles could otherwise block the channels,
causing bad performance, increased pressure drop and the
risk of boiling.
Systems with water or another evaporating liquid must
be equipped with the necessary bleed valve mounted in
a position higher than the heat exchanger. Air/gas inside
the liquid channels will reduce heat transfer and water
circulation, which also could cause boiling.
The liquid flow must be constant and with sufficient pressure
to keep its evaporating/boiling temperature above the plate
temperature. Local evaporation/boiling will adversely affect
heat transfer and water circulation, and may lead to a risk of
serious damage to the heat exchanger.
NOTE: The pressure at the coolant outlet must be high
enough to avoid boiling.
The VHX heat modules must always have the cooling fluid
circulating fully before the hot gas enters the heat exchanger.
The coolant must NEVER be allowed to freeze.
Never expose the VHX Heat Modules to excessive liquid
pulsations (i.e. cyclic pressure or temperature changes).
Gas side
The gas media should not be corrosive to the heat modules.
The gas flow must be started after, or simultaneously to, the
start of the liquid flow. If the liquid flow is interrupted, the
gas must be stopped or caused to bypass the VHX heat
modules to avoid boiling on the liquid side.
The VHX-DR Heat Recovery Center must not be operated
in such a manner that stagnant condensate is allowed to
accumulate. Never expose the Cross heat exchanger to
excessive gas pulsations (i.e. cyclic pressure or temperature
changes).
The VHX-DR Heat Recovery Center must NEVER be
operated without a coolant flow.
