Paraflow
After the boil, the wort (now bitter rather than sweet) is run off from the copper to a Fermenting Vessel via the heat exchanger shown in the photo, known in breweries as a Paraflow.

The Paraflow cools the wort from 100C to around 23 using cold liquor, which is thereby heated up and collected in the Hot Liquor Tank for use in the next brew.

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