Kitchen Drain Heat Recovery

[carlosgw]

An architect wanst to use waste heat from a commercial kitchen drain to heat fluid for a small sidewalk snow melt system. It sounds like a bad idea but I feel like I have heard of it before.
Even taking the drainage directly from a dishwasher - I would think grease would be a problem.
Any one heard of the application?

 

[MintJulep]

I would start with a simple heat balance.

My guess is that will show it to be not viable.

 

[SAK9]

Bad idea as the grease would stick to the pipe once it has cooled down and will eventually choke the pipe.

 

[GMcD]

I think he's another Google sound-bite ADHD architect who saw that GFX copper coil wrapped around the drain line to recover drainwater heat (

http://gfxtechnology.com/).

As a post above pointed out - do the energy balance and the capital cost of all that copper in the GFX coil and then compare the times that heat "might" be recovered from the warm drain pipe versus when the sidewalk needs heating. Back to basics....