Dealing with Down-Draught

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Curing 
Down-Draught
Problems

One of a series of 4 Posts on the General Subject

Downdraught problems have a fairly simple solution. Simply stated, it is to use the “Venturi Effect” to your advantage.

 Giovanni Battista Venturi 1746 - 1822 Italian Physicist

Thank you -Giovanni Battista Venturi for outlining this important effect for us - so many years ago, the auto industry would have been rightly screwed only for you!

The venturi effect states that where there is a flow across the end of a tube it causes a suction or negative pressure within the tube.

So the answer to your downdraught problem is to use a chimney cowl that ustilises the effect defined by Giovanni Battista Venturi.

Above is a diagram of the airflow in a Cylinder type Anti-Downdraught cowl. The arrows show a downdraught pushing down through the top of the cowl. The inner cylinder is the actual flue and this opens in such a way as to present the flue outlet at a right angle to the air flow inside the larger cylinder. The downward airflow blowing across the end of the flue outlet thus creates a venturi effect and thereby a suction up the flue pipe. It does not matter in which direction the wind pattern strikes the cowl, because the venturi effect will work with an airflow in either direction and cause a suction up the flue.

This is an example of a Cylindrical Anti-Downdraught Cowl

 

Above is another common type of anti-downdraught cowl. It is called a H cowl for obvious reasons. It works on exactly the same principle as the cylindrical type. Either type of cowl will usually solve a downdraught problem. These types of cowl will however NOT solve a pressure zone problem, as already discussed in the previous post - go look!

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Dealing with Downdraughts and Pressure Zones

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Pressure Zones

&

Down-draughts

So how do you deal with these two quite seperate problem; (1) Pressure Zones and  (2) Down Draughts? A Pressure Zone is created when a wind blows against a house or other obstruction causing the wind to dam up and form an area of raised pressure.

A down draught is formed when the wind blows over the top of an obstruction such as a hill, a large building, or grove of trees. The wind tends to curl down on the far side of the obstruction in a vortex type movement.

Downdraughts.

Downdraught problems have a fairly simple solution; simply stated it is to use the “Venturi Effect” to your advantage.

I mentioned the “venturi effect” in my last post on smoking fires, where I pointed out that an air intake with only a single inlet point could suffer from a suction effect rather than a desired positive pressure of air to a fire. Simply stated the venturi effect says that if you blow across the end of a tube, you cause a suction or partial vacuum in the tube.

An Artists Fixative Sprayer Uses the Venturi Effect

If you would like to demonstrate this effect, simply place a clear plastic tube or a drinking straw in a glass of water.  The water level inside the tube will match that outside of the tube. Now, blow across the top of the tube, like you might blow across a panpipes, and you will see the water being sucked up inside the tube. Artists use a simple sprayer that utilises the venturi effect to spray fixative onto a watercolour. Carburettors use the venturi effect to suck the fuel into the air stream and thus atomise the fuel.

How is the venturi effect going to help?  Well tune in to my next post and I will fully explain and make a few suggestions.

Pressure Zones

Pressure zones are another ball game altogether. Small pressure zones against the roof of a house can easily be overcome. You simply have to put the chimney well above the pressure zone - a taller chimney will generally do the trick. Simply add an extension to the chimney pot. Some problems have been cleared by adding 600mm to the height.

But what is the pressure zone is a very large one cause by an embankment etc.? If the pressure zone engulfs the entire house, it will usually cause no problem because all of the affected areas will have the same pressure. Problems only arise when there is a pressure differential; more pressure at the top of the chimney than at the bottom!

Curing Down-Draught problems next:

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Off the Air for Three Days

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3 Days Off-Air

Apologies to Readers

Seems there was an Attack on the Blog

Google temporarily removed this Blog because there evidently was an attempted attack on it. Must be making some bit of an impact to warrant that sort of attention!!!

I was a bit surprised at just how much it affected me to find 4 years of work wiped off the air without notice. It took me some time to figure how to sort the thing. But thankfully, all now seems to be working well again.

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Smoking Stoves and Fires part 2

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Pressure Zones and Down-draughts

A major cause of smoking fires and stoves is “down-draught”.  What causes downdraught?  Downdraught has two main causes. The most common is what is known as a “pressure zone”. When the wind blows constantly against any structure, it causes an area of raised pressure on the side where the wind is hitting.  An area of raised pressure will tend to push air down a chimney!

In the case of a sloped roof, the area of raised pressure can extend above the height of the roof itself. That is why it is very important to have the height of a chimney extend well above the ridge tiles.

If a house is built near an embankment or hill, that obstruction also causes a large pressure zone when the wind blows against it, this can also cause a problem area of raised pressure for houses in the vicinity.

When the wind blows over the top of an embankment, mound, hill, or other obstruction, it tends to curve down over the opposite side.  It would then be blowing down onto the tops of houses, and therefore down a chimney.

In the next post I will deal with the methods of combating the problems outline above.

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Smoking Stoves and Fires

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Smoking Stoves and Fires 

part 1

A common problem with solid fuel fires and stoves is that smoke or smell gets into the room. There are two main causes of this problem.

1. Insufficient Ventilation.

If you have modern double glazed windows and tight fitting doors, there simply will not be enough fresh air coming into the room to feed the fire. You must have a free and constant air supply into the room.

  Layout for an Underfloor Air Supply

Sometimes all that is needed is to have a small vent fitted into the door of the room this allows air to circulate. However, an under-floor air feed unit is the ideal solution for this purpose. Problem is that it is usually not a practical option as a retrofit, tearing up the floor of your living room etc.. If, on the other hand, you are building a new house or renovating extensively, and you intend to have solid fuel heating, it is very well worthwhile considering fitting an under floor draught supply.

This consists of two air inlet pipes underneath the floor. The pipes are generally of 10cm to 13cm diameter and must lead to two separate outside walls at right angles to each other. The two pipes come in and meet under the floor near the appliance in an air mixing box approximately 30 x 30 x 15 cm high. A third smaller pipe 75mm approx. diameter, leads to the area of the appliances air intake.

This system insures that warm air is not sucked out of the room to supply the fire, it also insures that there is a good and controlled air supply to the stove or fire.

The reason for this type of construct is to avoid a suction being created by a venturi effect, (wind blowing across a pipe will cause a suction), and it also avoids excessive air pressure when a strong wind is blowing directly into one of the pipes.

I will look at down-draught problems in the next post on this subject.

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Roll Your Own Wind Turbine Course

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 Finished Rotor Blades and Class

How would you go about gaining an understanding of wind power and wind turbines? Maybe take a degree course and get to know the maths and physics involved? Or maybe you might start learning with practical hands-on training taking very basic materials, wood metal, magnets wire etc. and build a capable fully working wind turbine from scratch.

There is now an opportunity to do just that at a unique privately owned training facility on a farm called ImEcoFarm.

The owner of  ImEcoFarm is a very brave visionary called Eddie Connors. Eddie has sunk A LOT of money into his pet project. He is a renewable energy enthusiast and a competent DIY man. Eddy has set up his farm at Clarecastle, Co. Clare as both a training facility and a lecture and exhibition centre.

The centre offers a range of hands-on practical training courses and fun demonstrations etc, for both young and old in renewable energy and eco topics. It is set in 100 acres of beautiful landscape along the Fergus estuary.

The course that takes my imagination is the:

Roll You Own Wind Turbine Course, (my title)

(the following is adapted from Eddies on-line information)

The course will run every week on Tuesday nights 7pm - 10pm. (28th Sep to 16th November.) It costs €320
The course is completely practical and hands-on, building a highly robust Wind Turbine with auto furling and electric braking to suit the Irish Climate. The machine is highly efficient and the only successful home built turbine for such a large size of machine.

 Wiring the Coils for the Generator

The course will focus on a 2.4m rotor diameter turbine. Participants will learn how this machine can be connected into the home for free hot water. This turbine can be connected easily and gives constant hot water from the wind. The different-sized machines, up to 5.2m rotor, are all similar to make, and we have detailed drawings for all machines.

 Coils detail

The Wind Turbine’s efficiency is due to:

1.    No Gear Box  - speed of propellers is the generator speed.

 The Resin Encased Coils being finished

2.    No Friction - Most wind turbines, including this design, use permanent magnets.  This means brushes are not needed as magnets travel close to the stator, without touching, so there is no power lost, due to friction.

 Working the Wood for the Blades

3.    Tried and Tested: This design is being built throughout the world for the past 30 years and even Military in Afghanistan have built this machine, due to its simplicity and robustness.

Attendance Certificate and Full course notes and Drawings for 2.4m, 4.2m, and 5.2m turbines are included.
The course will include all the practical phases of construction from very basic materials right up to a fully working machine. Even including the design and carving of the propeller blades.

 You can find out more here: http://www.imecofarm.com/

Good Luck Eddie. You are a brave man taking on this brilliant and interesting project in these difficult times.

UPDATE:

I was just talking to Carmen Cronin, on email a while ago, who works with Eddie, and she tells me that the September "Roll you own Wind Turbine Course" is fully booked out.

I am very happy that this is the case. Carmen said that there is a new calendar of courses and events just published on the website - so go have a look.

The link is above.

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SEAI on SEAI

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SEAI Sustainable Energy Authority Ireland

did a Review - Survey of it's Results

Not to be outdone,

SEAI Sustainable Energy Author Ireland aka ME

Has also done a "Bit of a Review"

On the 23rd of February 2007 I sent a letter to the then SEI now called SEAI (Sustainable Energy Authority Ireland). The purpose of that letter was to refuse the €4,200 grant that I previously had been awarded towards the cost of installing a wood-pellet central heating boiler.

Like SEAI, I am now doing a bit of reflection on how "effective" my actions were, and whether or not I am happy I took the action I did in cancelling my grant and intentions to install a woodpellet boiler. First here is my original letter:

My Letter to SEI 

Cancelling My Grant Application

23/2/2007

Dear SEI

I have done a great deal of research on wood pellet boilers, in terms of design, efficiency, and price. I have also looked into the supply situation for wood pellets in Ireland. My conclusion is that I am better staying with oil heating for now. I am therefore requesting that you cancel my application for now. When the marketplace is stabilised in Ireland, I would hope, maybe, to re-apply. I have given my reasons in detail below. Could I please ask you to have them advised to SEI policy makers, in the hope it might influence future planning.

1. Most wood pellet boilers do not have sufficient back-burn protection. Water quench is a fail-safe and simple method but is not fitted to most units. 
This could well be the cause of much trouble and litigation in the future.
2. Wood burning stoves and boilers produce creosote which can build up in the chimney and if ignited will burn fiercely causing much damage and great danger. The use of special dual walled high temperature stainless flues are required and these are very expensive, easily up to €1000. This is another possible time-bomb for the future.
3. Wood pellet supply in Ireland is far from stable. Disaster was barely averted this winter.
4. Wood pellet prices are far from stable. Prices not are close to oil prices, as oil has reduced and wood pellets have substantially increased in price.
5. Wood pellet quality varies a great deal. There is a great deal of sawdust in some pellets.
6. Storing wood pellets is a big problem, and costly, trying to keep them sufficiently dry.
7. Wood pellet stoves and boilers are overpriced in Ireland. There is a completely uncontrolled situation where major profiteering is taking place by some dealers. Most prices are well above those in Germany etc.
8. Some installers are way over priced. One quoted me €1000 for a boiler in an existing boiler house with flue and plumbing connection already there.
9. There is in-sufficient expertise among installers and service people in Ireland.
10. Spare part and warranty mechanisms are not fully established in Ireland.
11. There are some poor designs of boiler on the market, apart from the safety issues mentioned above. The good has not yet been separated from the bad in Ireland. Time only will tell.
12. Buying a wood pellet boiler now is simply subsidising the costs of future development. In a few years there will be standardised units from Danfoss and similar, and the whole thing will cost a half or less of the current crazy prices.

Regards,
Tony McGinley


My bit of a review:

1. Most wood pellet boilers do not have sufficient back-burn protection. Water quench is a fail-safe and simple method but is not fitted to most units. This could well be the cause of much trouble and litigation in the future. 

 (Now wasn't that true - all but the top of the range boilers had seriously poor or NO burn-back protection SCORE 1 Point)
 
2. Wood burning stoves and boilers produce creosote which can build up in the chimney and if ignited will burn fiercely causing much damage and great danger. The use of special dual walled high temperature stainless flues are required and these are very expensive, easily up to €1000. This is another possible time-bomb for the future.

(As yet -this has not presented as a serious problem and therefore remains open. NO SCORE)

 
3. Wood pellet supply in Ireland is far from stable. Disaster was barely averted this winter.

(At the time 100% the case, things have improved but no thanks to SEI. SCORE 1 point)

 
4. Wood pellet prices are far from stable. Prices not are close to oil prices, as oil has reduced and wood pellets have substantially increased in price.

(One of the HUGE selling points at the time for woodpellet heating was the VERY LARGE savings to be made over the cost of oil heating - what a load of bollix that turned out to be. SCORE 1 point)
 
5. Wood pellet quality varies a great deal. There is a great deal of sawdust in some pellets.

(Here again SEI didn't appear to care a dog's snot about the quality of wood pellets on the Irish market - a lot of problems were caused by poor quality pellets being freely sold on the market with no quality control or even a warning by SEI. SCORE 1 Point)

6. Storing wood pellets is a big problem, and costly, trying to keep them sufficiently dry.

(Ireland, apart from being famous as the RipOff capital of the whole world, is also famous fro being very green. Not only are the plants and trees green, everything, and I mean everything, goes green in Ireland. Why so? because Ireland is soo darn wet and humid. Now how would you keep a couple of tons of cornflakes crisp in your back yard in that climate? With great difficulty, do I hear you say? I would say it was almost an impossibility. Now did SEI forewarn the innocent and clueless public of this fact? No, at least not properly. SCORE 1 point.)

7. Wood pellet stoves and boilers are overpriced in Ireland. There is a completely uncontrolled situation where major profiteering is taking place by some dealers. Most prices are well above those in Germany etc.

( I proved this one so many times - I have not further need to restate the OBVIOUS. SCORE 4 points)

8. Some installers are way over priced. One quoted me €1000 for a boiler in an existing boiler house with flue and plumbing connection already there.

(Same as number 7 above. SCORE another 4 points)

9. There is in-sufficient expertise among installers and service people in Ireland.

(After just a few months of reading and asking around and with my bit of background in central heating technology, I was referred to an EXPERT. Expert my arse - but I knew a heck of a lot more that many in the business. Most retailers were CLUELESS about the technology. Many installers the same. SCORE 1 point)
 
10. Spare part and warranty mechanisms are not fully established in Ireland.

(Boy was I so right in this one - there were a few notable exceptions. The parts scarce and the price inflated. SCORE 1 point)

11. There are some poor designs of boiler on the market, apart from the safety issues mentioned above. The good has not yet been separated from the bad in Ireland. Time only will tell.

(I have been proved right here also. SCORE 1 point)

12. Buying a wood pellet boiler now is simply subsidising the costs of future development. In a few years there will be standardised units from Danfoss and similar, and the whole thing will cost a half or less of the current crazy prices.

(It is taking a lot longer than I anticipated for standardised and good designs to emerge. Much of the technology is still a load of rubbish cobbled together and costing stupid money. My advice stay away from wood pellets for a while yet. SCORE 1 point)



Now 17 Points out of 12 isn't bad is it?

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To Ministers Ryan & Gormley

In the light of the deepening Unemployment Crisis, the Banking Crisis, the Mortgage Crisis, the National Balance Crisis etc. etc. etc. etc. etc. I felt it was timely and appropriate to re-publish part of a piece I wrote two years ago.

This Winter - Let the Rich 
Worry about the Environment
The rest of us will have to concentrate
on just surviving the winter

This type of open fire sends some 85% of the heat up the chimney

Fuel Poverty a Reality this Winter

It is easy for the better off folks to be thinking about the environment but many will suffer Fuel Poverty this winter and they will just be thinking about how can they get by.

If you depend on an open fire it would be a really good idea to aim to buy a closed stove. There are some very reasonably priced plain cast iron stoves now coming onto the market. I will take a look at some of these in a future post.

Let the Rich Look After the Environment.

If looking after the environment means; GeoThermal at €9000+ , or Wood Pellet systems at €5000+, or Solar this or that at many many thousands. It starts to sound like a bad joke and an insult to a growing number of people.

If the Irish Government are even half serious about sustainability they should start a simple attic insulation drive straight away. They could also directly import and distribute closed stoves to every home that depends on open fires. They could save money by scrapping SEI and getting rid of the growing number of "experts" who increasingly are tending to soak up the money.

We all know what a grand job the HSE have done for the health service and the sickening cost of feeding this huge ugly paper shuffling monster.

And oh  - of course they, the government and their agents,  should get the finger out and actually do something on CFL and LED lighting.





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SEAI Grants how Effective?

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Ineffective

SEAI Grants

Earlier this year SEAI (Sustainable Energy Authority of Ireland) published a survey of the gains from various grant-aided schemes. The sad thing is, that despite HUGE investment of my money and your money, the gains, in many cases, were nil or close to nil.

I am not surprised

Does this surprise me??  No way - not in the least am I even mildly surprised. Why am I not surprised?  Read my blog!!

SEAI started out with very good intentions. They had an excellent website and they offered VERY GENEROUS grants for various sustainable energy projects.

However, they got it terribly wrong in some areas. Just looking at the case of wood pellet heating, they did not bother to:

(1) Check the availability of pellets. No pellets manufactured in the Republic at the time!!
(2) Neither did they make ANY PROVISION WHATSOEVER to protect the consumer from the hoards of Rip-Off cowboys waiting to pounce on a lush market.
(3) The entire €4700 value of the grant was absorbed by RipOff Irelands inflated prices for boilers etc., on the one hand, some 30% to 50% dearer than say Germany, and by installers charging €1000 to do a simple installation.
(4) Nor did they fully examine the quality and available of the technology, thus allowing “Heath Robinson” cobbled together systems and really clunky design gain a hold riding on the back of €4700 grants.
(5) Finally, or perhaps not actually finally as there could be many other instances outlined, they have not to the present time made any attempt to right the glaring problems that they have primarily created.

No then, it does not surprise me -at all at all - that SEAI grant schemes have been shown to be generally a waste of public money.


Self-Serving Institutions


A known problem generally with “Authorities” and “Government Agencies” is that these “Institutions” tend to develop a “self-serving” attitude, looking after their own and their employee’s needs and well being BEFORE the people or projects they are supposed to be serving.

Every dog on the road knows that the very best jobs in the country are with government agencies.

(1) They pay on average 25% - 50% better than the private sector.
(2) They carry guaranteed pensions, something the rest of us can never hope for.
(3) Short of committing murder, you cannot be fired,
(4) You are expected to work some 50% less than a similar job in the private sector.
(5) Sick leave, maternity leave, breaks, time to cash you wage cheque, and a dozen other little perks are included.
(6) They would appear to be recession proof, and
(7) They live in a twilight zone where normal science and business laws do not apply.

All and any of these would not and could not be supported in the real world. Only in the parallel world of the Government Agency, Civil Service, or County Council, could this alternative reality survive. The country cannot afford this kind of bullshit anymore.


Scrap SEAI

My advice to Ireland, to the sustainable energy community, and to the Government?  Cut the losses and please scrap SEAI now. A partially funded partially voluntary organisation would do much better. The grants could also be simplified and made much more attractive and less costly. Current grant schemes tend to favour the better off. Lower income groups cannot affort to go for fancy geo-thermal or €10,000 wood-pellet systems.

Simple everyday energy saving methods like fully promoting the change-over to CFL or LED lighting, and the promotion of fitting stoves and fireplace doors in place of open fires. All would effect greater savings than the disastrous wood-pellet cock-up or the less than well planned geo-thermal grants.

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