Pump-Assisted Split Loop Thermosyphon Heat Exchanger

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The Pump-Assisted Split Loop Thermosyphon (SLT) Heat Exchanger offers the highest levels of energy recovery and cost savings year-round for split airstreams, enabling installation into applications without side-by-side ducting. The pump-assisted, split loop design provides unprecedented installation flexibility. Estimations show possible annual operational savings in the $100’s of thousands while keeping incoming air clean!

This Pump Assisted AAHX recovers energy from either the exhaust or supply air stream during all seasons, allowing AHUs to consume less energy. Combining traditional air-to-air heat pipe technology and pumped two-phase systems takes advantage of both operational modes. In passive mode, the heat exchanger operates as a heat pipe with no electrical input required. This mode activates when the warmer air stream is physically below the cooler air stream. When the season changes and the relative temperature of the two air streams is reversed, a small pump is utilized to maintain the transfer of energy. Since the method of heat transfer inside of the heat exchanger utilizes the latent heat of the working fluid, the amount of flow rate required to transfer larger amounts of energy is a fraction of an equivalent glycol loop. It’s the combination of passive operation for at least half of the year and very minimal energy consumption during active operation for the other half of the year that enables such high overall energy recovery from this product.

  • Compatible with Large systems or distance
  • Energy Efficiency (especially compared to an equivalent glycol run-around loop)
  • Temperature control optional (without the need for bypass dampers)
  • Compact Packaging
  • Design flexibility
  • High Reliability, low maintenance needs

If a completely passive solution is not possible for all-season recovery, then this solution offers the next best thing. Passive, heat pipe-based solutions require horizontal and near level installation for adequate performance and this is just not possible in many applications. Plate heat exchangers require the air streams to be adjacent and intersecting at the heat exchanger and they are not volume efficient. Energy wheels also require the air streams to be in close proximity, they suffer from mechanical reliability issues, and they introduce cross-contamination between the two air streams. This solution does not have geometric limitations of other highly efficient energy recover heat exchangers and provides high performance / more cost savings compared to other products on the market. The ability to recover large amounts of energy over large distances all year-round with a minimal amount of energy consumption separates this technology from the rest of the field.


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