🚀 go-pugleaf

Nick Pine <nick@vu-vlsi.ee.vill.edu> wrote:
 
 There was also a 12 year old doing bubble experiments. She discovered that
 if she doped her standard bubble mix (1/2 cup green Dawn, 3 Tbs glycerin,
 and 2 quarts of water) by adding 1/4 tsp of lemon juice, the bubbles lasted
 111 seconds at 80 F and 506 sec at 45 F, vs 309 sec and 185 sec for the
 standard solution. 1/4 tsp of maple syrup changed this to 431 and 345 sec.
 She also tried adding jello, perfume, and another dozen substances... Her
 parting thought was quite serious: "Dust is the enemy of bubbles."
 
 So, led by this little child, let's all buy some glycerin, and try to invent
 a bubble wall, eg two pieces of single-layer polycarbonate plastic with butyl
 tape over a plastic 1x3" frame that can be filled between with bubbles at
 night that emerge from a PVC pipe with a few holes immersed in a soapy
 solution at the bottom, connected to a small aquarium air pump with a timer?
 This could be very useful in a passive solar house, like Beadwall. Simple
 movable insulation. During the day, the sun shines in on some thermal mass,
 and at night the glazing fills up with bubbles, keeping the heat in...
 
 Ohm's law for heatflow is a good start: the amount of heat Q in Btu/hour
 that flows through a wall with area A ft^2 and R-value R and temps Ti (F) on
 one side and To on the other, is Q = (Ti-To)A/R. 
 
 Here's one bubble wall test setup, a 2' cube divided in half by a bubble wall
 that might have an R-value of 2 when empty and 12 when full. We might make
 the cube out of 2" Styrofoam with an R-value of 10. One side could be kept
 at 32 F with some melting ice at the top, with some foam on top and around
 the ice tray, and the other side could be kept at 132 F with a thermostat
 and a light bulb, with a piece of aluminum foil to shade the bubblewall from
 the bulb. How much ice water might we collect in an hour with the bubblewall
 empty and full of bubbles? What might we get for readings in each case if
 we hook up the light bulb to a kWh meter? It's nice to have two ways to
 check the heatflow through the bubble wall.
 
                        .........................      70 F room
                     .   ice     ..          .  .
                  .........................     .
                  .           ..          .     .
                  .    To     ..  Ti      . R10 .  2'
               2' .    32 F   ..  132 F   .     .
                  .           ..  light   .     .
                  .           ..  bulb    .  .
                  .........................    2'
                        1'         1' 
                              ^
                              |___ bubble wall
 
 It takes 144 Btu to melt a pound of ice, and there are 3410 Btu in a kWh.

Nobody seems to have figured this out yet. Here's a hint:

                       32 F        132 F
       70 F ----wwww----|----wwww----|----wwww----70F
                R10/A   (R2 or R12)/4     R10/A

                ---->       <----         ---->
                 Q1           Q2           Q3

Nick