Winegrowers Supplies  -  Surface area needed for external cooling jackets or internal plates

  Temperatures for fermentation and storage

The surface area necessary for cooling a liquid in stainless steel tanks of different volumes depends on:-
    the ambient (air) temperature in the room,
    the temperature of the liquid inside the tank,
    the temperature of the water or glycol/water mixture flowing through the external cooling jacket, or internal plate/snake.

For cooling a fermentation, at between 12 °C and 16 °C, it is more efficient to use water alone.
For cold stabilisation, at between - 2 °C and + 2 °C, it is necessary to use a glycol/water mixture.

Here are some recommendations for the minimum surface area, in square metres, for an external cooling jacket:-

 Volume    Ambient temp 22 °C     Ambient temp 26 °C       Ambient temp 26 °C           Standard
 (litres)      liquid temp 18 °C          liquid temp 18 °C         liquid temp 18 °C         Jacket surface area
                 glycol/water 7 °C         glycol/water 7 °C          glycol/water 10 °C           square metres
_______   ________________     ________________     _________________     _________________

  1000                0.3                              0.7                              1.1                        1.0 / 1.1 / 1.4
  2000                0.7                              1.1                              1.6                        1.5 / 1.9 / 2.0
  3000                0.9                              1.3                              1.8                        1.8 / 2.0 / 2.4
  4000                1.1                              1.6                              2.1                        2.3 / 2.6 / 2.8
  5000                1.6                              2.2                              3.0
  7000                2.1                              2.8                              4.0
10,000               2.8                              3.6                              5.3
20,000               5.3                              6.7                              9.0

In the English climate, the ambient temperature is more likely to be 18 °C to 20 °C, with cooling to 12 °C for white wines.

An internal cooling plate, snake or heat exchanger is much more efficient, so requires only 72% of the surface area of an external jacket.

Tank manufacturers recommendation is that the external cooling jacket covers about 30% of the surface area of a tank.

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