Over the summer I finally managed to finish the fridge conversion for my new cold smoker and it has been operational now for a couple of months. Over the last couple of weeks I have now consolidated the automatic environment controls into a single control unit.
The smoker has been built from a commercial stainless steel catering freezer with the chiller unit removed. The cosmetic sides of the chiller unit housing were then cut back to allow it to fit in the smokery (my converted shed).
An electrical control box was then used to create the cold smoke generator housing, which holds an AMNPS type pellet smoke generator.
The stainless steel smoke feeder tube has holes drilled underneath and has a smoke baffle that sits on top. Below you can see the cold smoker in place next to the FEC-120 hot smoker.
In the flu I have also added a 4" variable speed brushless fan so that I can accurately control the air flow through the unit. This leads to an external exhaust vent. Below you can see the vents for both the FEC-120 and the new cold smoker.
In my old smoker I have been manually controlling both the temperature and the humidity however this has now been fully automated using a TH20 Temperature and Humidity controller.
This has still to be physically attached to the side of the smoker, but I will do this when I have finished "tweaking". I have already tidied up the internal cabling though since these photos were taken.
The Humidity is controlled through an ultrasonic humidifier that fits in the bottom of the smoker and the temperature is controlled using a combination of a pair of 100W ceramic heaters and a Peltier chip sandwiched between two fan assisted heat sinks for cooling.
Below are photos of the Peltier cooling unit as I was putting it together.
The metal plate fits to the top of the smoker (magnetically attached) with the cooling exchanger inside the smoker and the heating exchanger on the outside. Photos below show it in place while it was being tested.
This will comfortably keep the inside of the smoker up to 17-20 Deg C (30 Deg F) cooler than the outside temperature.