Please could you explain the attraction of the intermediate stage of acoustic energy transfer in the generation of electrical power? What is the "magic" about this compared to say - a simple thermocouple

With currently available materials, thermocouples are expensive and have low efficiency.
Semiconductor materials produce many volts per degree K, but only operate below about 125C. The best I have seen are les than 5-7% efficient. Compare this with 15 – 20% for a thermoacoustic engine.

The requirement for a thermocouple is high electrical conductivity with a low thermal conductivity. Unfortunately,...

One of the main research drivers is to reduce the inhalation of wood burning products. Currently many stoves are open fires within a dwelling.
 
Score reduces the overall wood products by 3 times, due to improved stove efficiency and by over 95% within the dwelling due to the chimney.

 

Do you have a timescale on which things are expected to happen?  What are the major landmarks?

The project is 5 years long.

The first 3 will research the various aspects (see other FAQ's for detail) and the last two will be organising dissemination, training and building up production.

At the end of the 5 years, we are aiming to produce significant quantities of Score stoves per year.

Part way through the research phase we will have a working and instrumented demonstrator, and later on a...

We expect to have a working unit at the end of 2008, units for testing in selected areas in 2009, manufacturer selection in 2010 and volume production (1 million per year) after 2012.

80% comes from the EPSRC. (Engineering and Physical Science Council, a UK government organisation) the other 20% comes from the universities themselves.

See this link for the EPSRC press release.

Are there other potential markets for this technology? And who are your industrial partners

Yes.

Due to confidentiality issues we cannot disclose names.

Can you tell me which governments and institutions in developing nations in Africa and Asia are involved? how important will it be to make this a technology that becomes rooted in the local technical infrastructure, rather than one that is supplied by developed nations.

We are in discussion with government representatives of developing countries. The discussions are at an early stage, so it is not appropriate to name them at this stage.

Hower, we do have letters of support that will give you an indication of the areas we intend to cover.

 

Another major research element is the social context for the stove. We want to ensure that it fits in with the local communities at a number of levels.

 

The size and shape of the stove has to fit local needs, for example, some areas use flat plates for cooking, others require hobs to carry large cooing pots. The stove may be used in a single dwelling or a community facility such as a School,...

We are aiming to have the majority of the stove made locally. This will stimulate businesses in the rural community.

 

There are other business opportunities for example selling the electricity to charge phones and laptops, selling ice etc. We are eliciting the support of universities within each developing country to train people in the manufacture of Score and promote other business opportunities....

Presumably the biggest factor is cost. So far this technology seems to be for top-end uses such as military - can it really be done cheaply enough?

Yes, cost is a major factor and our target is £15 to £20, although it is still attractive at twice this figure. As a comparison, current prices to supply electricity in a rural area is $500.  A major research topic is how to make the device at low cost. The linear alternator will probably be made at a low cost manufacturing centre. We are aiming to have the rest manufactured locally within the...

Why is this a better way of making heat or cooling in developing countries? Even if it is more efficient than, say, wood-burners, does that necessarily help if it is dependent on an energy-grid infrastructure?

Over 2 Billion people use open fires to cook and they have no access to electricity. The cost of supplying electricity to rural homes is very expensive; typically, $500 for a score size device. Additionally, existing stoves loose 93% of heat to the surroundings. Score will improve the efficiency of the stove, so less time is spent foraging for food, and generate electricity and cooling at the same...

Isn't it generally deemed a bad idea to put cookers and fridges together? Why is that not a problem here? Is it essential that the two things work together - do you lose efficiency, for example, if you want to refrigerate but not cook, or vice versa?

The cooling is inherent in the design, hence why they are close together.

 

The heat of the stove is kept away from the refrigeration unit with only the pipes necessary to carry the hum from engine to the fridge connecting the two.

 

The thermo-acoustic engine is essentially a Stirling engine with no moving parts. (other than the gas). Burning wood heats the pipe at one place and cools...

How are the acoustic waves generated, and how are they used to induce cooling/create heat?  Where ultimately does the power come from

The thermo-acoustic engine is essentially a Stirling engine with no moving parts. (other than the gas). Burning wood heats the pipe at one place and cools it at another.  The pipe then resonates, rather like an organ pipe. The gas moves from the hot part, and expands, to the cold part and contracts. Just like a stirling engine this transfers energy to the gas and makes the hum louder. In the score...

Thermoacoustics refers to the generation of sound waves through the non-uniform heating of gas — illustrated by the ‘singing’ of hot glass vessels which can be heard during the glass blowing process.

 

The concept of the proposed device is based on proven thermoacoustic engines and refrigerators developed for applications such as combustion-fired natural gas liquefaction and radioisotope-fuelled...

The wood is burned to produce heat. This then goes into a specially shaped pipe which produces areas of high and low gas pressure in such a way as to generate sound (in similar way to a singing kettle).

 

The sound energy is then converted into electricity by a linear alternator (a sort of giant microphone which absorbs the sound).

The electricity is then used to power the device.

Thermo acoustic engines work from 40 to 400Hz. The score design is aimed at 50Hz to match mains frequency. The sound is contained within the pipe and is quiet on the outside.

Common Score questions are answered here.