[Stoves] Concentrators in ND TLUDs

[Crispin Pemberton-Pigott]

Dear Paul and All

There are two methods not mentioned:

1. The use of a set of secondary air holes correctly positioned and sized to have the same effect as a disk with a central hole. This is applied in a Vesto (ND-UD)

2.  The use of an annular gap admitting air in an unbroken stream instead of jets creating, in the same way, the same effect as a disk+hole without a disk. This is applied in the POCA (ND-UD) charcoal stove. 

I have a quibble with the reference by Bob to the energy applied to the primary air as 'suction' by introducing a venturi. Because the introduction involves a change in the combustion performance, there can be an apparent loss of energy, but the system is a vertical ND one so the reduction of the space for a secondary flame means more (free) draft. The result is not predictable on the basis of gas flow alone, one has to consider the change in geometry AND the change in the temperature and velocity simultaneously. In short the draft on the primary supply may decrease, increase or remain the came. 

Thanks for the stimulation
Crispin
-----Original Message-----
From: Paul Anderson <psanders at ilstu.edu>
Sender: "Stoves" <stoves-bounces at lists.bioenergylists.org>
Date: Sat, 23 Feb 2013 14:26:29 
To: Robert Fairchild<solarbobky at yahoo.com>
Reply-To: Discussion of biomass cooking stoves
	<stoves at lists.bioenergylists.org>
Cc: Christa Roth<Christa-Roth at foodandfuel.info>; Hugh McLaughlin<wastemin1 at verizon.net>; Tom Reed<tombreed2010 at gmail.com>; <terra-matricula at hotmail.com>; Discussion of biomass cooking stoves<stoves at lists.bioenergylists.org>; Karsten Bechtel<karsten at tech.mak.ac.ug>
Subject: Re: [Stoves] Concentrators in ND TLUDs

_______________________________________________
Stoves mailing list

to Send a Message to the list, use the email address
stoves at lists.bioenergylists.org

to UNSUBSCRIBE or Change your List Settings use the web page
http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org

for more Biomass Cooking Stoves,  News and Information see our web site:
http://www.bioenergylists.org/