Comments on: anarchy roundup: CHP and grid emissions http://carbonlimited.org/2007/09/04/anarchy-roundup-chp-and-grid-emissions/ low carbon energy and engineering Sat, 19 Feb 2011 23:14:49 +0000 hourly 1 http://wordpress.com/ By: CHCP saves carbon? the question is moot. « carbon limited http://carbonlimited.org/2007/09/04/anarchy-roundup-chp-and-grid-emissions/#comment-361 Tue, 30 Oct 2007 18:34:00 +0000 http://carbonlimited.wordpress.com/2007/09/04/anarchy-roundup-chp-and-grid-emissions/#comment-361 [...] saves carbon? the question is moot. Over the summer there was a debate between some big names in engineering over whether combined heat, cooling, and power (CHCP) using [...]

]]> By: Jason Hawkes http://carbonlimited.org/2007/09/04/anarchy-roundup-chp-and-grid-emissions/#comment-321 Thu, 06 Sep 2007 16:00:09 +0000 http://carbonlimited.wordpress.com/2007/09/04/anarchy-roundup-chp-and-grid-emissions/#comment-321 I’ll get my coat!

]]> By: Casey http://carbonlimited.org/2007/09/04/anarchy-roundup-chp-and-grid-emissions/#comment-320 Thu, 06 Sep 2007 10:06:11 +0000 http://carbonlimited.wordpress.com/2007/09/04/anarchy-roundup-chp-and-grid-emissions/#comment-320 No worries J. Except in CHP based on stirling engines, electricity generally comes first. Most chp is based on internal combustion engines or gas turbines. In both these cases, gas combustion drives a mechanical process, which is then used to generate electricity. Heat is then recovered from the jacket and flue gasses to be used for other things: space and water heating, absorption chillers, process heat for manufacturing, etc.

So in the case of internal combustion CHP, it’s just like hooking your car engine up to a generator and using the heat from the radiator to warm your house.

]]> By: Jason Hawkes http://carbonlimited.org/2007/09/04/anarchy-roundup-chp-and-grid-emissions/#comment-319 Thu, 06 Sep 2007 09:26:11 +0000 http://carbonlimited.wordpress.com/2007/09/04/anarchy-roundup-chp-and-grid-emissions/#comment-319 Hang on, doesnt the heat come first? If so, all heat not converted to electricity
is wasted and I have never seen a jenny that is better than about 40% efficient. Does the CHP jenny work differently to all other jenny’s?
If I am completely wrong and moronic, say so- or this will run and run.
Oh dear, sorry to do this- Im sure you are at least as busy as I am!

]]> By: Casey http://carbonlimited.org/2007/09/04/anarchy-roundup-chp-and-grid-emissions/#comment-318 Wed, 05 Sep 2007 11:17:40 +0000 http://carbonlimited.wordpress.com/2007/09/04/anarchy-roundup-chp-and-grid-emissions/#comment-318 Taking an example (just to be indicative, right? not precise): an engine might have an electrical output of 1MW and a heat output of 1.4MW. Assuming the electrical efficiency is 33%, that’s 3030kW of fuel coming in. 1MW is coming out as electricity, leaving us just over 2MW of waste energy. The system catches 1.4MW of the waste heat, i.e. just under 70% of the waste energy from the electrical conversion process. That’s not bad, and much more than the 1/3 you suggested.

]]> By: Jason Hawkes http://carbonlimited.org/2007/09/04/anarchy-roundup-chp-and-grid-emissions/#comment-317 Wed, 05 Sep 2007 09:26:58 +0000 http://carbonlimited.wordpress.com/2007/09/04/anarchy-roundup-chp-and-grid-emissions/#comment-317 So why cant the opposite be the potential norm?. I realise this has little to do with intensity factors but, unless stirling engines and the like are much more efficient than other turbines, we are still only effectively recovering 1/3 of the waste heat

]]> By: Casey http://carbonlimited.org/2007/09/04/anarchy-roundup-chp-and-grid-emissions/#comment-316 Tue, 04 Sep 2007 20:32:16 +0000 http://carbonlimited.wordpress.com/2007/09/04/anarchy-roundup-chp-and-grid-emissions/#comment-316 This may be an ironic question so I’ll post an answer cautiously. Your ideal solution is spot on: CHP uses the waste heat from electricity generation.

]]> By: Jason Hawkes http://carbonlimited.org/2007/09/04/anarchy-roundup-chp-and-grid-emissions/#comment-322 Tue, 04 Sep 2007 18:31:42 +0000 http://carbonlimited.wordpress.com/2007/09/04/anarchy-roundup-chp-and-grid-emissions/#comment-322 I’ve always wondered about CHP. Now I’m no techy and, inviting a guffaw, I ask the following question:

Seeing that our need for electricity is all year round, but our need for the kind of heat/ electrical energy output ratio delivered by CHP is only necessary for the heating season- wouldnt it be better to develop a machine that works with the reverse in mind.

Most turbines are only 35% efficient, or so. Why use the waste heat from the heating part of a CHP system to generate electricity, when we would be better served by using the waste heat from electricity generation to provide heating?

Unless, of course, my ideas on how CHP works are entirely wrong- in which case you are free to guffaw, look at me askew next time you see me and suggest that I may be in the wrong industry

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