[TRNSYS-users] Drain water heat recovery

[Jeff Thornton]

Graham,

The first step is to pick the heat exchanger model that best fits your 
drain water heat recovery device.  Then you'll have to create the hot 
water draw profile AND the drain water profile.  These should be 
different profiles as things like baths and clothes washing do not have 
coincident supply and return water flows.  You may also have to account 
for the cold water draws/dumps depending on the location of your heat 
exchanger.  I would avoid Type 14 forcing functions and instead rely on 
the Type 9 data readers or even the new Event-Based Data Reader from 
TESS to drive the flows through the system.  I've done a few of these 
drain water heat recovery models and the key is getting the flow rates 
right.  The Building America program has a utility for creating 
event-based draw profiles - you may want to start there.

Jeff

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Jeff Thornton
President - TESS LLC
22 N. Carroll Street, Madison WI USA 53703
Office: (608) 274-2577  Fax: (608) 278-1475
www.tess-inc.com
E-Mail: thornton at tess-inc.com

On 09/11/2012 11:47 am, Graham S. Wright wrote:

> I would like to use TRNSYS to model drain water heat recovery, if
> there are suitable components.  How should I approach this ?  The
> focus is residential (single and multi-family).  The output I am
> looking for is basically the annual average increase in the
> temperature of the incoming cold water, post-recovery.
>
> On a related note, I think I remember seeing somewhere on the
> internet that some in the US had put together a detailed hot water
> draw profile with thousands of events that required six-second time
> resolution.  Does this ring a bell and if so how would one get that
> into a TRNSYS schedule ?