Knowde Enhanced TDS
Identification & Functionality
- Product Type
- Technologies
Features & Benefits
- Ready-to-Use Product Features
- Product Highlights
The Micro Channel Heat Exchanger (MCHE) development originates from the automotive industry where it is used since more than twenty years now. They have however only recently been introduced to the HVAC&R industry. Some of the big advantages are that they are lighter, more efficient and they lower the required refrigerant volume. Another advantage of an MCHE coil is that it’s made out of aluminum only. This makes it less vulnerable to galvanic corrosion (caused by combining dissimilar metals) than the traditional RTPF coils . The MCHE coils not only bring the above mentioned advantages , they also bring with them extra challenges. In corrosive environments, not only the fins will corrode but also the aluminum tubes are at risk.
- Features
- Micro channel tube protection - Blygold PoluAl MC completely seals off the vulnerable tubes from the environment. With a very thin single layer treatment the coating prevents possible pitting corrosion and refrigerant leakages.
- Solar radiation reflective - The sunlight radiation reflecting pigmentation does not only prevent coating breakdown due to UV, it also reduces sunlight radiation heat absorption compared to black surfaces.
- Improved water drainage - The coating surface creates improved water drainage properties for the microchannel coils. When water drains from the coil the risk for corrosion and accumulation of pollution is significantly reduced!
- Spray applied technology - The proprietary Blygold spray technique results in 100% metal surface coverage without bridging of fin spacing between fins or fin enhancements.
Applications & Uses
- Markets
- Application Area
- Application Method
- Application
Pitting corrosion - Aluminum has a protective oxide layer by nature that prevents an overall corrosion process as can be seen on steel substrates. In environments with high salt exposure aluminum tends to corrode very locally with high salt exposure, aluminum tends to corrode. This results in local deep material loss also called pitting. On micro channel HX this may result into refrigerant leakages through the thin aluminum tube wall.
Salt accumulation - The high fin density combined with the extreme fin enhancement design results in highly efficient heat transfer. Down side of this design is the rapid salt and pollution accumulation due to the very narrow spacing. With salt accumulation occurs an increased corrosion risk.
Water drainage - Horizontal flat aluminum tubes combined with narrow fin spacing result in a perfect geometry for water retention after rain. This also means that accumulated pollution and salts between the fins are not washed out of the coil.
- Application Process
Coating flexibility - Blygold PoluAL MC is a flexible coating. Even after thermal cycle testing the coating is able to withstand fin bending without risk of cracking or delaminating. Another major advantage of this coating flexibility is that flat micro channel coils can be bent after the coating has been applied. Tests have shown that the coating is still in perfect condition on the bended areas.
Application flexibility - PoluAl MC is applied through Blygold’s special spray techniques. This makes the application very flexible. It can be applied to any size of micro channel heat exchanger without any restriction. When coils are already bent they can also be treated with PoluAl MC.
- Applications
- Qualified Blygold Applicator
Properties
- Typical Properties
| Value | Units | Test Method / Conditions | |
| Adhesion Cross Hatch (USA) | 5.0 | B | - |
| ASTM B-287 | min. 4000 | hours | Acid-Salt Spray Test |
| ASTM B117 | min. 4000 | hours | - |
| Electrochemical Impedance | 6,78E +07 | Ω.cm2 | - |
| Kesternich (2.0 ltr SO2) | 80.0 | cycles | - |
| Layer Thickness | 20 - 40 | μm | - |
| Pressure Drop | 0 - 20 | % | - |
| Dry Temperature Range | -30.0 | °C | - |
| Thermal Resistance | 0 - 3 | % | - |
| UV Resistance | Excellent | - | - |
Technical Details & Test Data
- Technical Information
- Coating type: Aluminum Impregnated Polyurethane
- Pretreatment: Blygold Aluprep HX
- Substrates: All aluminum heat exchangers like MCHE and radiators
- Color/pigment: Sunlight radiation reflective silver, sacrificial to substrate
- HX water drainage: Up to 30% improvement compared to uncoated MCHE coil
- SWAAT (Test Until Leakage): 3-5 times longer compared to uncoated coil
- Coating Performance Testing
