Dear Friend
As addidional information:
Timo Jodat from www.y-energia.com is also at present cooperating on a research project for the University of Jyvaskyla in Central Finland - together with Arjo Heinsola - another good friend and colleague.
This project is to evaluate the effectivness of high-effective Chinese evacuated tube solar collector elements in cold climates.
Electro-engineer Arjo Heinsola is also one of the best experts on low-cost small-farm biogas systems in cold climates. Of course the ability /possibility to heat the material in the digester is of the greatest importance in their sucessful operation.
Greetings - JF