Rotary Energy Recovery Heat Exchanger
Product Description
Rotary heat exchanger (wheel) is mainly used in building ventilation or in the air supply/discharge system of air conditioning equipment. The wheel transfers the energy (cold or heat) contained in exhaust air to the fresh air supplied to indoor. It's one important equipment and key technology in the field of construction energy-saving.
Rotary heat exchanger is composed of heat wheel, case, drive system and sealing parts. The heat wheel rotates powered by the drive system. When outdoor air passes through half of the wheel, return air passes through reversely the rest half of the wheel. In this process, about 70% to 90% heat contained in the return air can be recovered to supply air to indoor.
Working Principle
Rotary heat exchanger is composed of alveolate heat wheel, case, drive system and sealing parts. The exhaust and outdoor air pass through half of the wheel separately, when the wheel rotates, the heat and moisture are exchanged between the exhaust and outdoor
air. The energy recovery efficiency is up to 70% to 90%.
Wheel Materials
The sensible heat wheel is made by aluminum foils of 0.05mm thickness.
And the total heat wheel is made by aluminum foils coated with 3A molecular sieve of 0.04mm thickness.
Case Construciton:
Wheel Construction
The wheel of the rotary heat exchanger is made of alternating layers of flat and corrugated aluminum foil to form the alveolate shape. Various height of corrugation is available. Flat surface ensures minimum leakage.
Interior spokes are used to mechanically bond the rotor's laminations. These are threaded at the hub and welded at the periphery.
Laminar Flow Channels
The wave type structure of the wheel forms narrow channels in the direction of air flow. The air flow forms a laminar flow inside the wheel when passing through it. When the wheel rotates, dust won't accumulate on the channel since outdoor air and exhaust air respectively flow through the channels from two directions. This is called self-cleaning.
Double Sealing System
Unique double-sealing system is installed around the rotor periphery and along the central beam. The sealing
materials are soft and dense of small friction and longer service life.
Purge Sector
Because of the structure of rotary heat exchanger, the outdoor air and exhaust air will mix. According to the air
velocity, wheel rotating speed and direction, purge sector is installed to prevent the exhaust air from entering the
outdoor air. The purge sector enables a small fraction of outdoor air to blow back the exhaust air in the alveolate
holes to its side. A minimum pressure difference of 200Pa between the outdoor air side and the exhaust air side is required to ensure the cleaning effectiveness. With all conditions provided, the sector can ensure a leakage below 0.3% from exhaust air to outdoor air.
Positioning of Fan and Wheel
The cleaning effect of the purge sector is bound up with the fan position and static pressure difference between outdoor air side and exhaust air side. When the pressure difference is less than 200pa, the cleaning effect is not guaranteed.
Selection Program
We have developed a calculation program for simple selection of a rotary heat exchanger model. It can not only be
used as a single design selection program, but can also be combined into your program by DLL. We can add it to
your program upon your request, too. Please contact us for the selection program.
Application:
Rotary heat exchanger can built in air handling unit(AHU) as a main part of the heat recovery section. Usually
side panel of the exchanger casing is unnecessary, except that bypass has been set in AHU.
It can also be installed in the ducts of ventilation system as a main part of the heat recovery section, connected by
flange. In this case, side panel of the exchanger is necessary to prevent leakage.
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