[Stoves] FA vs ND in TLUD stoves -- not what you might expect about cost

Tue Apr 4 17:30:35 CDT 2017

Dear Nikhil

>”…why haven't FA stoves captured even 1% of the household cooking market in 30 years of this list's existence?”

The main reason is that the power needed to run the fan is more than a lot of people can manage. There have been fan-powered stoves for a ling time in the Boy Scout community. The patent was about 1978 or something – we discussed it here a long time ago. The inventor passed away. Boy scouts get their batteries from Dad. Not so easy long term in India.

Dry cell batteries are about $50 per KHW. Charging was out of the question. In India the Oorja was plugged into the wall from the start. That means there was mains.

So I guess the reason is electricity, meaning access to it.  The stoves have been great right from the beginning. So they cut a niche but in places where stored power was available.

The TEG’s were not available until quite recently at a price anyone could afford. Now they are $1 per watt.

I saw a presentation at DUE today on a concept for a double gated MOSFET that is suited to getting power out of low voltage AC sources and rectifying it (1.4v) quite efficiently. That would really help fan stoves because a booster can take that to 5 or 12 volts easily and energetically, cheaply.

Regards
Crispin

Crispin, Paul:
Are FA stoves more amenable to control and hence more convenient in cooks' views (subject to fuel, meals, pots diversity, etc.)?
If so, no further debate necessary as to other metrics.
It's not Crispin's job to convince Paul nor Paul's to convince Crispin. FA and ND will find their niches if stovers stop arguing about technologies in isolation from the geography and the demographics of cooking.
Still waiting.
Paul: all (controllable) power to you if FA TLUDs are more convenient.
Crispin: 3We is better than -1We power only if there is no grid (or a reliable one). The question I have is, why haven't FA stoves captured even 1% of the household cooking market in 30 years of this list's existence? If this is more difficult than rocket science, go to NASA; it's going to have much more money than EPA.
Please stop boiling water. Unnecessary increase in GHG emissions.

Nikhil

------------------------------------------------------------------------
Nikhil Desai
(India +91) 909 995 2080
Skype: nikhildesai888

On Tue, Apr 4, 2017 at 9:18 PM, Crispin Pemberton-Pigott <crispinpigott at outlook.com<mailto:crispinpigott at outlook.com>> wrote:
Dear Paul

"...are head and shoulders above any "ICS" ‎..."

What is the metric(s) for which you are making this claim?

How many 'equal stoves' without a fan do I have to demonstrate in order to convince you there are natural draft options?

FYI I have been looking at getting three watts out of a stove at a low cost. The output is five volts DC, regulated, with varying current depending on the temperature.  The components needed cost $7.50 retail. That includes a USB port for charging. I don't know what the selling price of the stove will be, but it is really likely that being able to produce three watts instead of consuming one watt is easily worth the additional cost.

What do you think? Are you amenable to making a self-powered unit?

Thanks
Crispin

Stovers,

FA (forced air or fan assisted) and ND (natural draft) versions of TLUD
stoves have existed since the original work by Tom Reed (both types) and
Paal Wendelbo (only ND) in the 1980s - 1990s. No need to describe them
here. Check the written documents.

What is not discussed much is the relative cost of these two major
types. Of course, the QUALITY of the stoves will impact the price, but
let's assume that quality is similar, such as using stainless steel in
key parts, and using modern manufacturing with possible high volume
production . Such stoves already exist or are nearly ready for the
market, but are often overlooked.

In my opinion, many TLUD stoves are "over-weight", being made of metal
far thicker than is necessary. But assume similar weight optimization
for both the ND and FA TLUDs.

Basically, a TLUD is a fuel chamber with additonal walls and legs in
various configurations. The differences because of ND or FA are
primarily because of needed draft for combustion quality:

1. ND needs natural draft, and therefore vertical rise is important for
negative pressure. An "internal chimney" (or riser before the gases get
to the pot), or a chinmey after the pot is essential.

2. In contrast, FA needs draft, but it is from a the push of a fan or
blower.

The costs of "chimney components" vs the costs of "fan components"
becomes the crucial issue. And there are expensive and inexpensive
variations of both.

But from what I am seeing, the chimney costs remain constant in each
cultural context. Many Latin American stoves utilize chimneys, as do
stoves in mountainous and cold-climate areas.

But for the fan components, costs have been reducing and reducing more
while the general availability of getting the few Watts of electrical
power is becoming easier and more widespread, essentially being costs
covered by other desires such as lighting and charging mobile phones.

Basically, the costs to make a real chimney-based stove vs the componets
in a functional FA TLUD stove are about equal now, and will be lower for
the FA TLUDs as volume production kicks in.

Today, 2017, if a society (or individual household) has economically
sustainable grid electricity, or a solar-powered lighting system, or
established battery-recharging services, (and the education and
experience to reasonably care of an electronic device), a FA TLUD will
be a reasonable addition to the household.

Certainly, in ASPIRATIONAL TERMS, households will move toward the
Fan-Assisted TLUD stoves, with cleaner combustion that can compete very
well with LPG on cleanliness, while being environmentally and
financially superior.

In terms of clean combustion of source-fuels that are dry biomass such
as wood, TLUD stoves --- especially with fans --- are head and shoulders
above any "ICS" (Insufficiently Improved Cooking Solution) stoves that
use solid fuels.

Paul

Doc / Dr TLUD / Prof. Paul S. Anderson, PhD
Email: psanders at ilstu.edu<mailto:psanders at ilstu.edu>
Skype: paultlud Phone: +1-309-452-7072<tel:%2B1-309-452-7072>
Website: www.drtlud.com<http://www.drtlud.com>

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