Day Two

After our success with the pump and the small closed loop we needed to see if it could pump water through all the equipment we were likely to use in the refrigerator and the suit. All in all, that amounts to about five or six metres of tubing. We filled the tubes with water and connected up to the type of device that we might use in the fridge and tried it out. Nothing happened. Tried it again, still no joy. Ellen even tried to blow the water through the system and found she couldn’t do it so our little pump would have no chance.

So we needed another plan to try and solve the problem. They filmed us chatting about other possible ways of pumping and we talked about perhaps using the foot pumps that were lying around.

Then it occurred to us that there might be an air lock in the system. We had tried to fill the tubes as best as possible but in all the bends and coils of tubing it is possible that there might be air trapped in one of the bends. So we carefully sucked water into the system and poor Ellen and I ended up having to drink quite a lot of it. After playing around for ten minutes or so we gave it another try and it worked! It was slower, of course, but we could see some small air bubbles passing really nicely through all the tubing. Ellen put some red dye into the water so that we could see it better.

There were still problems with the pump, though. For one thing, not all the rollers were identical and sometimes the drill would stall if the machine squashed the tube too much. We took it all apart to try and make the whole things more symmetrical and this helped. We then tracked down the cause of the problem to the tube itself. Yesterday, when the pump seemed to work so well it was really hot, and we had been filmed in the afternoon. All this time the equipment was in the Sun; consequently the tubing and the water were nice and hot and so this kept the tubing very flexible. Today it was cooler and the water is cooler and so the tube is stiffer - enough to jam the pump!

Once we had warmed the tube up it all worked well. It should be very hot in Death Valley so the tube should be nice and flexible - but of course we are aiming to pump cool water through the system so how will this affect the tube?

Kathy's first experiment didn’t get a good enough pressure / vacuum to cool the water. Found an air leak via the thermocouple wiring and after a few other mods we were getting 60 % atmospheric pressure / vacuum (roughly 400 Torr) which is pretty good for the simple equipment we were using. However still no joy getting the zeolite to do anything and the water just sits there; no cooling… A really good Rough Science test though.

There is still so much to do for this experiment that we bring equipment back to the rooms and have a takeaway and a drink and carry on. Mike B starts work on another method of cooling the fridge.