Using compost to heat buildings

The Japanese have created a model tea house that is heated with compost in the walls with pipes running through it. It is an elegant design that could be replicated  in cob houses and other natural building, greenhouses, or other types of buildings. It's good to see the concept is spreading.  We have seen several working compost showers.  How could you capture the heat in your compost pile? The link below has more information on the tea house. http://inhabitat.com/circular-pod-tea-house-is-heated-by-compost/