[permaculture] any biologists out there?

paul wheaton paul at richsoil.com
Sat Dec 19 19:28:17 EST 2009


Most of your questions have already been addressed in the thread link.

In a nutshell:

    - this is the sort of thing that comes up regularly at permies.com

    - legionellae hurt you only if you breathe in the mist.

    - I don't know what DHW is

    - some of your questions are the same questions we are currently stuck on

    - both solar and jean pain methods appear to be susceptible to
this problem at certain times.

On Sat, Dec 19, 2009 at 1:49 PM, Lawrence F. London, Jr.
<venaurafarm at bellsouth.net> wrote:
> paul wheaton wrote:
>> When heating water with solar or the jean pain method or .... whatever
>> ... it seems wise to consider legionnaires disease.  But in order to
>> consider it, it seems we need to know the enemy.  And we're coming up
>> short on a few things.
>> http://www.permies.com/permaculture-forums/2607_0/alternative-energy/alternative-hot-water-and-legionnaires-disease
>> The question is:  what is the reproduction rate of legionella?  Would
>> they reproduce faster in pond water than in, say, well water?
>> Distilled water?
> Kevin Topek, in this list, might have an answer as he seems
> knowledgeable about health and safety issues. Misha Gale-Sinex, once in
> this forum (see the archives) and occasionally in sanet-mg list will
> probably have a quick answer for you. Of course, Google it.
> I never thought about the possibly of legionella on the farm or
> homestead. How did this subject come up in the first place? If you're
> heating DHW for dish wash, heat, bathe etc. then it would seem the only
> issue would be getting water on you rather than in you or on washed
> dishes used wet or breeding in clothes as well as airborne pathogens
> from dried particles (does it need a moist environment to survive?) or
> from water vapor, humidity, condensation on objects and steam.
> Do I assume correctly that it presents a risk from external contact
> or only from internal contact, including breathing the contaminants as
> airborne dry particles or moist, in steam, mist, spray?
> What environment does it need to survive and propagate? What nutrients
> does it need? Where is is usually found?
> There is also the known risk of pathogens breeding in hot tub water.
> The Japanese obviously figured out how to avoid this problem over the
> centuries of bath house use.
> One way to avoid the problem, just as with common hot water heaters,
> used, of course, for storage, long term, might be to use solar or Jean
> Pain apparatus to transfer heat to your DHW
> by way of a heat exchanger located in the actual DHW storage tank,
> heating a continual source of clean water. Instead of running your clean
> cold water infeed through the actual heating apparatus you run it into
> your storage tank and heat it with a heat exchanger carrying hot water
> from the collector, recycling that fluid continuously while your
> pressurized DHW cycles from its source (city, cistern or well) through
> your storage tank to where you use it, never in contact with the heating
>  equipment. Remember the sludge buildup inside conventional hot water
> heaters (minerals and microorganisms, if I am correct)? Most of this
> could probably be avoided using a heat exchanger as a DHW heat source.
> Or just use hot water direct from the source for house or greenhouse heat.
> Another option is using a solar closet, heating water in barrels located
> in a super insulated room with hot air from a collector inside a glazed
> case. Cycle hot water from your Jean Pain equipment or solar collector
> through the barrels also. Extract the heat by way of a heat exchanger to
> generate DHW, stored in its own insulated tank or figure out a way to do
> demand batch DHW generation in a hot box of some sort. The heat
> exchanger itself, if it can contain an adequate volume of water, might
> serve that purpose by default. Google "solar closet" and "Nick Pine"
> for more info on solar losets or read the Usenet newsgroup
> alt.solar.thermal or alt.energy.renewable. I have archives of saved
> Usenet posts on Nick and his solar closet technology here:
> Top level directory:
> http://www.ibiblio.org/ecolandtech/alternative-energy/
> http://www.ibiblio.org/ecolandtech/alternative-energy/solar/
> This is solar closet central:
> http://www.ibiblio.org/ecolandtech/alternative-energy/solar/Nick.Pine/
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