[permaculture] any biologists out there?

Lawrence F. London, Jr. venaurafarm at bellsouth.net
Sat Dec 19 23:10:51 EST 2009

paul wheaton wrote:
>> The solution of using a heat exchanger to keep the water used in the
>> house, in human contact, out of the plumbing system of the heater
>> element, i.e. the plumbing and apparatus that is in direct contact with
>> the source of heat, would probably work to prevent contamination of DHW
>> with the pathogen.
> And lots and lots of permie sites use something much simpler.  As part
> of a demonstration of living a simpler life.
> I really like the idea of something simpler, provided that the
> simplicity doesn't get people sick or dead.

Sometimes simple isn't the right solution. The various water borne 
diseases are a serious matter. Personally, I would not necessarily take 
a chance with the popular simple solutions unless I could come up with 
mods that ensured safety of use. Not to say that they wouldn't be safe
as designed and used. HS Tarm wood Danish fired boilers send very hot
water into a huge tank for long term storage. Into this is immersed a 
heat exchanger with cold i and hot out ports for clean DHW. I think
contamination from pathogen growth occurs when the system is stagnant
for long periods or successive short periods. during which the microbes 
can incubate and propagate.

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