[sarcher]

I used to work in AD/Composting and the issue I've read about with compost heat recovery was the cost of the recovery system (compost piles are very large) and short equipment life span due to damage by loaders/environmental degradation.

The most consistent use of compost heat has been to ensure proper pathogen reduction in certain waste materials such as wastewater byproducts. A popular example of this is called a 'dutch tunnel' (add 'composting' to that if you google it) where you have a pretty robust, loader accessible composting container which largely self-heats for pathogen reduction. I use the term 'largely self-heats' because there are aeration/mixture characteristics that are required for proper temperature development.

Searching EPA 40 CFR 503 is a good introduction to the process, because there is been a lot written about it and you can easily find guides/introductions.