Heat pipes have been used successfully in a variety of HVAC design applications over the past 35 years for passive dehumidification ranging from fan coils to very large commercial applications. HPT manufactures dehumidifier wrap- around heat pipes, dehumidifier controllable heat pipes, and heat recovery systems. Heat pipe products provide the following benefits:
- Free precool and reheat
- Allows entire system to work more efficiently
- Increases latent capacity without additional energy consumption
- Dehumidifies air entering the ductwork. Helps better meet ASHRAE 62.1 Standard.
- No moving parts to break down or wear out
- Often allows downsizing of entire HVAC systems
- Helps prevent IAQ problems associated with high humidity
- Helps meet ASHRAE Standard 90.1
The DHP Series (Dehumidifier Heat Pipes)
Passive humidity reduction with no moving parts, pumps or additional external energy input of any kind. Using the proven Dehumidifier Heat Pipe Principle, the DHP typically precools incoming air by 5 to 15° F instantly, allowing the cooling coil to meet the dew point faster and with greater efficiency. Also, condensate removal by the cooling coil is greatly enhanced. One of the most valuable aspects of heat pipe dehumidification is the fact the process of reheat uses the same heat extracted in the precool section of the heat pipe. So, for every BTU provided as reheat, another BTU is taken out of the air stream as precool.
- May replace active reheat totally or partially
- Uses no pumps or any other mechanical devices
- Operates without interference of existing circuiting
- Low pressure drop
- May allow downsizing of entire A/C system
Dehumidifier Heat Pipes in an HVAC System
HPT factory assembled and shipped to air handling equipment manufactures to install. Standard or controllable options
The HRM Series (Energy Recovery Heat Pipes)
No outside 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 or Phenolic 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 difficult to repair.
Isolated Air Streams
Dividing plates that 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. Moreover, the center dividers can be separated by up to 8” and foam filled to reduce or eliminate any chance of supply air contamination by the exhaust air through the heat pipes.
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 more compact than other heat pipes. A six-row heat recovery heat pipe can be fabricated with a thickness of as little as 9 inches.
Summer and Winter
The same Heat Pipe can be used for equal calls for cool and heat recovery or optimizing thermal recovery in the season that matters most, while still allowing for appreciable recovery in the other season. This is accomplished without any changeover mechanism. The temperature difference between the air streams activates the energy recovery.
Configurations of Energy Recovery Heat Pipes: