Advantages of a Hybrid Falling Film Design

Originally published in HPAC Engineering, this article by Ian Casper of Johnson Controls outlines the benefits of falling film evaporators – namely efficiency and simplicity – over a traditional flooded evaporator design. A particularly useful way of thinking about the efficiency of falling film comes from a cooking analogy:

“As any cook who pours a little water into a hot pan knows, heat transfer is very effective when a thin film of liquid contacts a hot surface. For that reason, heat transfer in falling film evaporators is very efficient. The evaporation of a thin refrigerant film covering a tube happens more easily than with submerged tubes. The high heat transfer coefficient boosts chiller efficiency.”

As Casper shares, the straightforward design of falling film helps eliminate potential leak points and may become even more advantageous as new, more expensive HFO refrigerant blends become mainstream.