Understanding Temperature Control in Bioreactor Systems

Related Vendors

DÜPERTHAL Sicherheitstechnik GmbH & Co. KG

Glatt Ingenieurtechnik GmbH

Italvacuum, Srl

Meaningful Data

In order to calculate the specific internal energy of a 50 L stainless steel reactor, weighing 100 kg, with 5 L in the jacket, 7 L in the chiller and 3 L in the hoses at a ΔT of 10 °C: For the culture medium (aqueous so we will use the same values as water): 50 L = 50 kg 50kg x 1.0 cal/g °K x 10 °C ΔT = 500 Kcal For the water in the jacket, hoses and chiller: 15 L = 15 kg 15 kg x 1.0 cal/g °K x 10 °C ΔT = 150 Kcal For the bioreactor: 100 kg x 0.11 cal/g °K x 10 °C ΔT = 110 kcal The total internal energy to be removed is therefore 760 Kcal. Since the cooling capacity of chillers is traditionally given in watt hours: 760 Kcal x 1.16 watt/kcal = 881.6 watts/h

A chiller with a cooling capacity of 882 watts is therefore required to achieve a 10 °C temperature decrease in one hour. To calculate the specific internal energy for different time frames, the one hour watt value can simply be divided by the new time period (in hours).

Additional Factors

These calculations do not, however, compensate for poor heat transfer, or heat gained/lost to the surrounding environment. This is attributed to slow or non-existent stirring, the use of materials such as glass that possess poor heat transfer properties, and a lack of insulation.

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