Monday, July 3, 2017

It's a mystery!

After a few hours experimenting with the new bilge fan, I'm presented with somewhat of a mystery. I am no further forward in having an answer as to whether the fan does anything or does nothing. Part of the answer is probably due to the weather which changed (somewhat unhelpfully) from sunny to cloudy.

The chronology went something like this...
  • 1:13 started the ventilation system with the end of the unit including the filter standing on the bottom step in the entrance, with the door open enough to accommodate it. It was 95 in the bedroom area. The tube was extended half way through the galley and I could feel a breeze.
  • 1:25 I took the filter off to see what difference that made. There was an appreciable increase in the amount of air flowing through. It was still 95 in the bedroom.
  • 1:32 still 95F in the bedroom. Taking the thermometer and leaving it in the air from the ventilation tube dropped the thermometer to 91. Then I took the thermometer outside and it rose to 93 and stayed at 93.
I concluded extra induction seemed to make little difference to overall temperatures. This was good and bad news. The good news was I didn't have to scrabble around under the bus installing ventilation. The bad news was I'd not achieved much. Having said that, the next thing was to see what the fan does when blowing air through my exhaust vents.
  • 2:05 With the interior temperature at 97, the fan was connected to an exhaust vent. By 2:12 by my calculation all the air should have been expelled from the bus. I gave it til 2:20 for good measure
  • 2:12 Well, I went outside and when I returned found the duct tape attaching my ventilation duct to the exhaust vent had fallen off so at 2:15 I started again. The internal temperature was still 97F.
  • 2:40 I stopped the experiment. The thermometers hadn't changed any but the bus felt cooler.
One thing I haven't mentioned is that the humidity dropped while my fans were going. Then afterwards the humidity climbed. I believe at one point it was 50% but at the point of writing, the thermometer read 93F and 58% humidity.
  • 3:27 I restarted my bilge extraction fan. The thermometer read 93F and 58% humidity.
  • 3:42 I stopped the fan. The thermometer read 93F and 59% humidity.
The biggest challenge thus far has been the useless nature of duct tape. I know I'm only holding things temporarily in place while I experiment but even so, it could be better!

A few years ago, I lived in a townhouse and never once used the air conditioning. Sure, it got warm in summer but I couldn't afford to blow money on air conditioning. My income was solely what I had from my job and it didn't pay much. Roll on a couple of years and I was stuck in a job that paid even less - so little that I could not afford to pay rent and had to move out of my disagreeable little hovel.

Back in my hovel, I found that a cheap little fan though not as icy cold as an air conditioner made a huge difference as did the fact that it naturally gets cooler at night. For a long time I've maintained that it's better to have moving air than icy cold air. Indeed, standing outside, it seemed cooler than inside the bus but wasn't really. It was due to lower outside humidity and the fact the air was moving.

As I wrote this blog entry, though initially I sweated profusely, when I remembered my $6 battery powered desk fan, I felt cooler having switched it on. My existing extraction fans are CPU fans. They remove a decent amount of air. I did have some 3V fans there before that probably didn't remove quite as much air but which worked. It seems to be a case of diminishing returns. It's something I shall have to think more on. Perhaps the answer lies not in more powerful fans but in more low powered fans just to keep the air moving toward the back of the bus.

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