sewage heat pump issue

[US Iceman]

Hi LC,

I would say the shell & tube exchanger is more forgiving in this application as the tubes would be easily cleaned. The project in Sweden does have shell & tube heat exchangers used on it I believe.

If there is a chance of minor particles or sediment, the tube velocity should be maintained at least 6 to 8 feet per second (1.8 to 2.4 meters per second) to provide a cleaning action on the tube ID.

The fouling factor should also be increased above the limits used for HVAC applications to also provide some additional run-time between cleanings too.

If the shell & tube exchanger is fabricated with channel heads and covers, the cover plate can be removed quickly to allow the tubes to be cleaned quickly.

The application of any heat exchanger is based on the application. If the fluid has solids or will accumulate material, then the system is dependent on the filters used. There are some centrifugal separators that can be blown down on a regular basis to maintain effectiveness of the seperators.

If filters are used, perhaps they should be provided with mechanical scrapers to keep the filters clean for longer periods of time.

Do you have any written material in English that may describe the heat pump you are thinking of?

[US Iceman]

Here are some links for more information:

http://www.stowa-selectedtechnologie...eat.Pumps.html

http://www.gryaab.se/admin/actions/u...2-10%20EGü.pdf

[Andy P]

The fouling factor should also be increased above the limits used for HVAC applications to also provide some additional run-time between cleanings too.

It used to crack me up that the US tables of fouling factors started with distilled water (FF=0.0005 if I remember correctly) and went all the way up to "The Chicago Sanitary Canal" at 0.008 (imperial units). The second worst after the CSC according to the table was the East River, NYC - must be all the ex-mobsters swimming with the fishes in their concrete overshoes!

Another laugh is that the Americans call imperial units "English units" - we've been blaming the English for all sorts of things for years!

Thanks for the memories
Cheers
Andy P