[Greenbuilding] Energy Star RE: Water heater comparison

[Dr. C.F. Vasile]

Clarke: To the contrary, the tankless diversity factor is about 10:1 because people do not not take 1000 simultaneous showers @ 7:15 each morning as you postulate. BUT, due to long recovery times of tank-type water heaters 1000 of them are guaranteed to be on at the same time after morning showers are taken. 
   Therefore, a power grid peak shower draw of 1000 tank-type water heaters is about 1000 x  20 Amps = 20, 000 Amps; compared to a tankless, cold-climate draw  of about  than 1000 x 80 Amps/10 = 8,000 Amps (or 4,000 with a quality DHR system). 
   Load profiles in hotels is quite different because guests seem frolic in showers for longer periods of time in the evenings as illustrated in the graphs @ http://www.gfxtechnology.com/hotel.html. 
Carmine
www.gfxtechnology.com  
--------------------------------------------------
From: "Clarke Olsen" <colsen at fairpoint.net>
Sent: Wednesday, February 04, 2009 7:08 PM
To: "Larry Brydon" <lbrydon at reliancecomfort.com>
Cc: "Carmine Vasile" <gfx-ch at msn.com>; <speireag at gmail.com>; "Greenbuilding Forum" <greenbuilding at listserv.repp.org>
Subject: Re: [Greenbuilding] Energy Star RE:  Water heater comparison

> 
> On Feb 4, 2009, at 4:47 PM, Larry Brydon wrote:
> 
>> Consider condensing gas storage type water heaters as an  
>> option....... essentially energy storage batteries that help shave  
>> peak loads.......Imagine what the demand would look like in a  
>> subdivision of 1000 homes if at 7:15 each morning 1000 tankless  
>> water heaters all fire up at once, with an average demand of 200 mbh.
> 
>> Along with the toasters and coffee makers.....
>> Hadn't thought about it that way.
>    Clarke Olsen