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Dr Bob

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Dr Bob last won the day on November 14

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About Dr Bob

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    Muppets on the cut
  1. Eco Fan

    ..but it goes through my 'Vacuflush' system ok as there is not substance in it at all.
  2. Eco Fan

    The claim was not unsbustantiated. They provided data that they assumed to 'prove' the claim. As a scientist with lots of experience in writing and reviewing papers, I gave some criticism earlier in the thread that would have helped more in the proof - but it is possible that they did have the proof. As it was 10 years ago, it is now impossible to question the paper. No one (other than Mross) has tried to discuss the paper. Yes, I think there is doubt based on the comments I made (and Mross made) but it would be wrong to 'flush it down the loo' and say rubbish without more reasoned debate. The information on fuel usage actually seems quite robust. We need to see the follow up paper.
  3. Eco Fan

    I counted 56 temperature sensors out of the 60 plus 'tags'. Maybe I miss counted. Ive only got 20 fingers and toes. Some of the sensors were outside the room but suspect they would help in the heat modelling in calculating losses through the walls - but obviously not as relevant to the 'internal' probes (hence a proportion of the 10K readings would be less important ). I know you have been saying there is a second paper but I never saw that comment. What page was that on? I was confused that the overall paper - 40 odd pages - (havent got it open at the moment) seemed to be made up of 2 papers, the first saying what they were going to do and the second (after the set of appendicies) with the results. I wonder then, is the second part - the second paper you mention? I will do a bit of searching for more papers.
  4. Eco Fan

    Co'mon, keep up. I pointed you at this earlier in the thread. In Appendix 2, it lists the 56 thermocouple probes connected to their data logger. Each run was 3 hrs (=180 minutes) and they took a temperature recording every minute. They list the position of each probe. Runs were done in pairs, one with a fan and one without. During a run they would therefore have recorded 56 results per minute which by my calculation (multiply by 180) says 10,000 readings ish (actually 10,080 which sounds like an extraordinary high darts shot). The heat map would have used a set of the 56 readings to compute a 2d and 3d picture of the room from the simulation software – of which we are only seeing a 2d image. What has not been discussed from that paper is the claim of 15% fuel saving. Other than 'dissing' the whole paper, I've not heard any constructive comments on what they have done wrong to come to that conclusion. I, like you, cannot believe a fuel saving.
  5. Eco Fan

    Exactly. A peltier powerd bike I assume? Or was it a a Vulcan Vincent?
  6. Eco Fan

    Now that I totally agree with. Yes there must be a cross-over, which is exactly my point. If I am sat in the front cabin at 10ft from the stove, I dont want to feel an air flow - so a 12v fan would be bad. I dont know what the crossover is, but I do know that the fan produces an environment that is more comfortable than without it as my feet are not as cold and the temp feels more even. What I feel is pretty much in line with the heat maps produced earlier in the thread which will have been based on 10,000 temperature recordings per run. I think the crossover will vary person to person and that is why there is so much 'positioning' on this thread. It is not as easy to see on this thread but if you look at the first page of the other one, there are quite a few early respondents who acknowledge both low fan effectiveness but with improved thermal comfort.
  7. Eco Fan

    Yes totally correct. But what temperature are you? From your avatar I guess you are less than 20degC but I am 39deg C ish. Air flows of 20-25deg will cool. Ever tried sailing in the Med? Stiffling sat in the sea in no wind (in the shade) but when the wind starts, it is great - all at 30deg C. At around the 20-25deg our cabin is normally, it is more comfortable not to feel the draught. I would not want a 12 volt computer fan blowing at me. Try it, you will feel a draught.
  8. Eco Fan

    Machpoint, you have got it wrong again. Of course it feels colder the higher the air flow at constant temperature. Do you ever watch the TV weather forecasts? The higher airflow takes heat away from the body (when less than 38dec ish) so you feel colder. It's called 'wind chill'. At no flow there is stratification so the floor is much colder than at 3-6 ft off the ground. A slight air movement to disrupt the stratification will make the temperature more uniform hence my comment of warmer. More than 'slight'movement and they you have the cooling draught. Simple, isnt it? .......Ah, damn, that's how I was going to do my video later in the week!
  9. Eco Fan

    Nope, it was me who made that quote. Too big a fan causes a draught that will feel cold. No fan and your feet get cold. A gentle fan to disrupt the air is needed but how powerful is that? edit Mross is it your radiant stove?
  10. Eco Fan

    Just saw Bluestringpudding's essential oil post on the other thread. Slam dunk. 4-0.
  11. Stove Fan Effectiveness Question

    Wow, that is lateral thinking. Have a greenie!
  12. Eco Fan

    My fan is sold with a quote of 265 CFM flow and makes a big deal out of it. Surely they cant be lying?
  13. Eco Fan

    If they did that then they wouldnt be able to sustain two separate 400 post threads. Whilst Mark, it may be clear to you and me, and the few others - given the video and 2 papers (discussed here and on the other thread), it is very difficult to change the minds of those who refuse to accept facts. I think enough information has been presented that does support the benefit of the fans, but other than the (enjoyable) debate between myself and Mross, there have been very few 'serious' comments on the efficacy of the data. There certainly seems to be a lack of engineers or scientiests to discuss the data so instead it is just black or white comments of what seems like 'lay people' which dont really help the discussion. What would really help here is an engineer with fluid dynamics experience who can talk about heat dispersion. I think you are right Marc in that we dont understand the power of a fan that is actually needed to improve thermal comfort. We certainly dont need a fast 12v fan - as that will only make us feel like we are in a draught. You actually only need a small flow to disturb the stratification (or whatever we call it!!) and it should improve thermal comfort. Perhaps the ecofan is good enough. I keep saying it but some of us are more sensitive to heat so a small amount of air movement might be fine. It is intersting that the Waterloo paper claims the Eco fan 800 saves 15% fuel. I have not yet seen any argument that would say that was wrong - although was the paper published on April 1st?
  14. My BMV counts in the amphrs during charge in line with the 'instantaneous' Amps until it hits the setting that you have defined as the target tail current and then it goes to 100%. Sometimes however it gets totally confused and jumps to 100% when you dont expect it - and the amps in will not be right anyway (charging efficiency), so it is useless to pay any attention to the state of charge value when getting near full. As everyone esle has said, use the tail current. I reset my 100% every time I get it back to 100%. You obviously are getting welll charged in the summer/autumn but a once a week charge is just not good enough with no solar in the winter. I cant quite see how you can only be going down to 80%SOC and charging once per week? It hasnt been that sunny has it? Have you got something drawing power without going through the shunt that is taking you lower than 80%. Of course, If the SOC reading is confused and you are not reaching 100%, then reading it when it says 80% could be false. I use the voltage at rest first thing in the morning to give me my approx state of charge - but cross checked against Ahrs out from the last time it was full. Oh to have 1000W of solar!
  15. Eco Fan

    It must be good - I said it twice
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