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Eugene, I've a friend who owns and runs one of the largest organic farms in Wa. state, near Tonasket, on the E. side of the cascades. He grows heirloom tomatoes, berries, fruit and vegetables. He has been running Pex through the tomatoe greenhouse with huge success, using several propane fired boilers.
He'd like to install ground source heat pumps with 3 million Btu capacity. He has many acres to utilize for the piping. He'd like to run a biodiesel co-generator to offset the costs...any advice for a sensible "green" system design?