An integrated industrial plant includes various systems, all of which use a cryogenic liquid obtained from a common source. One system includes a fermentation unit, in which cold air, chilled by heat exchange with the cryogenic liquid, absorbs excess heat generated by the fermentation. Another system is a lyophilization unit, in which a refrigeration step is performed through the use of air that has been chilled by heat exchange with the cryogenic liquid. Another system is a device for freezing discrete samples of biological products, the samples being frozen by partial immersion in the cryogenic liquid. The invention substantially reduces the use of electric power, and provides systems which operate economically and reliably.