Re: GBlist: boosting storage temp

["Carmine Vasile" <gfx-ch@email.msn.com>]

Hello John:

    How do Australians handle the dual problem you indicate:

            "However Australia also has anti-scalding requirements built
into legislation
             - such that water from domestic outlets (e.g. in the bathroom)
must be set at
             a maximum of 50*C [122*F]. Storage temperature must be 70*C
[158*F] or
            more for microbial control."

without degrading the Energy Factor ["EF"] of the water heating system?

    I suspect the real motive behind the 120*F set-point recommended in the
U.S. was anti-scalding law suits against electric utilities, coupled with
the now-defeated, proposed U.S. DOE standards requiring electric water
heaters to have high EF.

    If one simply makes a thermostatic tempering valve an integral part of a
storage water heater, its EF will drop due to higher standby loss with a
storage temperature above 70*C [158*F] for "microbial control"& convection
around the tempering-valve loop.

    This approach is fine with a tankless water heater, but the utilities
would lose stand-by-loss revenue, so they may have adopted a "Class Action"
[the movie] Mentality ---
        The Scaled May Sue ---- The Misdiagnosed May Not.

    At least that's what was implied by some after an EPRI presentation on
Legionella at a Water Heating Workshop sponsored by the California Energy
Commission and SMUD. See the July/August 1997 issue of "Home Energy" for
coverage of this Workshop.

Best Regards,
Carmine

----- Original Message -----
From: John Gelder <john.gelder@wanadoo.fr>
To: <greenbuilding@crest.org>
Sent: Sunday, January 23, 2000 5:43 PM
Subject: Re: GBlist: boosting storage temp


> Brian Hood
>
> Australia and New Zealand work to a joint standard [AS/NZS 3666.1
> Air-handling and water systems of buildings - Microbial control - Design,
> installation and commissioning] to deal with legionella. The standard is
> cited in the Building Code of Australia. There is another part for
> maintenance, and an associated handbook for guidance. The standards cover
> everything from cooling towers to showers. You can get the documents off
the
> Standards Australia website [http://www.standards.com.au/]. Hospitals, by
> the way, are a major risk in acquiring legionella - occupants have reduced
> resistance and the water systems often include a warm water supply line,
for
> example.
>
> However Australia also has anti-scalding requirements built into
> legislation - such that water from domestic outlets (e.g. in the bathroom)
> must be set at a maximum of 50*C. Storage temperature must be 70*C or more
> for microbial control. The difference requires the use of tempering
valves,
> mixer valves, or whatever.
>
> Cheers
>
> John Gelder
> 8, rue Benjamin Franklin
> 75016 Paris, France
> tel: 33 1 45 20 98 93
> john.gelder@wanadoo.fr
>
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