RMH aquaponic greenhouse distillation.

The problem with the barrel for an RMH in a smaller green house is that you don't want an intense heat source because the plants to close to it will suffer. Another problems is Salt build up in aquaponics systems over time in some places depending on initial water quality. So what if you set out to partially solve both problems at once? Replace the barrel of the rocket stove with a water jacket. Then over it put distillation condenser columns. Most of the heat should be radiated from the larger surface area of the meaning a less intense heat. Any steam vented out of the top of the stacks simply pipe to another area of the green house and open vent. It would be a no pressure or negligible pressure system so the risk of explosion should be basically zero. Water vapor in a cold greenhouse is basically no risk. Worst case the shell condenses it instead. Add a large pipe off to the side tied to the bottom of the water to put a fill valve float in and you could have it autofill. If for some reason you lost all water the pipe would let some air in and chimney effect should provide some circulation of air to help keep the inner barrel from burning out. And being a batch system should do great things for distillation because the columns could cool off between batches giving really good condenser efficiency in a basically open air system.

So what am I missing? Why would this not work?