The Pioreactor has onboard heating and thermoregulation. This is great for most microbes who enjoy a slightly warmer than room temperature environment. However, sometimes you want a cooler environment. The Pioreactor can't create produce a cool environment, but you can place the Pioreactor in a cold environment and then let the onboard heating heat to a precise temperature.
That's what we did this week, but to the extreme. Here in Ontario, it's a cold -4℃ / 23F. We put the Pioreactor in an insulating cooler, and powered it from an outdoor electrical outlet. Even with the cold temperatures, the Pioreactor behaved great! Due to the heat given off by the Pioreactor / Raspberry Pi and being inside an insulating cooler, the vial temperature stabilized around 4℃.
We could even turn on heating and thermoregulation to target any temperature above 4℃. See figure below.
In practice, the Pioreactor will operate well in fridges and freezers, preferably in a dry location. From there, you can turn on heating to target a temperature above ambient.