Insulation Experiment

[Forrest747]

Kids Science Fair is in October and my daughter want a project and i suggested a issue we are having here.

Alot of thought has gone into the insulating of the trailers weither to insulate or not. So we came up with using a friends Dairy Queen cake frezzer and building two boxes one just out of 3/4 plywood and another same dimensions but a cookie cutter with rigid insulation. She will use a data logger recorder which has a external temp probe as well as an internal one.

The data logger will be placed in the center on a foam platform (simulates mattress) and teh temp probe will be placed in the other box on the same size foam platform. Will let sit in the garage for two days and at the end of the second day will take to Dairy Queen put in thier -30 degree freezer and leave over night. We have to buy a cake I am told, who am i to disagree with that service fee.

We will not be looking at the actual final temp but at the trend of the cooling. i am told that the longer the the temp stays higher than it will be an indication of more insulating property. I have no clue how to calculate the R value of what we are doing.

[bobhenry]

here is the R values for the most common insulation products rated per inch of thickness.

R-Value Table
Material R/Inch
Insulation Materials
Fiberglass Batt 3.14
Fiberglass Blown (attic) 2.20
Fiberglass Blown (wall) 3.20
Rock Wool Batt 3.14
Rock Wool Blown (attic) 3.10
Rock Wool Blown (wall) 3.03
Cellulose Blown (attic) 3.13
Cellulose Blown (wall) 3.70
Vermiculite 2.13
Air-entrained Concrete 3.90
Urea terpolymer foam 4.48
Rigid Fiberglass (> 4lb/ft3) 4.00
Expanded Polystyrene (beadboard) 4.00
Extruded Polystyrene 5.00
Polyurethane (foamed-in-place) 6.25
Polyisocyanurate (foil-faced) 7.20

[Techguy]

Many of the rigid insulation pieces have the R-Value stamped on the back of the material.

[Forrest747]

The purpose of this test is to see what difference not insulating make

[Fishingtomatoseed]

I like it. Can't wait to see the results.

[S. Heisley]

I look forward to seeing your results.

[Lgboro]

I look forward to your findings also -- I would insulate just for the sound deafening even if I had no heat/cooling benefits.

[grant whipp]

This is an interesting experiment and I'll look forward to the results! However, we need to realize that this will only give you static results ... in the real world of day-to-day teardrop (or tiny trailer) use, you need to factor in the human (and animal, if you travel with pets) elements. Our bodies produce a certain amount of heat, and will greatly affect how well any amount of insulation will work.

As an example, my girlfriend & I were perfectly comfortable in our paneled-but-uninsulated Modernistic on a cool night with just a blanket and the windows open ... but, when we added her 4-year-old grandson on the shelf over our feet, it got hotter than blazes and we had to open the door and kick off the blanket!

If perhaps the experiment could be modified so that a heat source, like possibly a light bulb, could be added to the inside of the box, then it might produce some extra data that could actually apply to the real world use of our trailers ... ...? Just a thought ...

Good Luck, and like I said, looking forward to the results!

CHEERS!

[Forrest747]

Good idea for a second test. take the wood box add the light and a thermal switch set to keep a constant temp in the box and see the amount of watts used to keep it at a constant temp, while in the freezer.

May keep this one from daughters data do not want to take over her project and have it look like it was dads project to the science fair judges.

[bobhenry]

Found this....


"The human body maintains a basic minimum rate of heat production at about 250 Btu/hr during sleep, the heat equivalent of about 75 watts, and about 400 Btu/hr (120 watts) when awake but sedentary. As bodily activity increases, the rate of oxidation of food, with its attendant release of energy, must increase. The level of heat production for light work will be about 650 Btu/hr (190 watts), the extreme value for heavy work, about 2400 Btu/hr (700 watts)."

So to scale down would you have to divide the cu feet of the model by the cu feet in a standard tear to get a factor to multiply the 75 watts by? Sounds like a real small light bulb. maybe a 2 or 3 watt night light ??

[Forrest747]

Using a C9 clear bulb, relay, thermal switch I can see the amount of watts used in teh box. Using my cumlative feature on my watt meter i can see how much power is being used to keep it at 60 degrees F.

[danlott]

Using a C9 clear bulb, relay, thermal switch I can see the amount of watts used in teh box. Using my cumlative feature on my watt meter i can see how much power is being used to keep it at 60 degrees F.

Or you could see what the temperature inside the different boxes were if you just left the light on with the wattage scaled to what a human body would be.

This experiment is very interesting and I believe we all are looking forward to the results.

Dan

[Techguy]

Glad to see I am not the only geek here!

[Cdash]

Can you talk her into a 3rd box with simulated studs and insulation?

[DezPrado]

A light bulb to produce heat eh? Guess we're talking incandescents here & not them new fangled led s or eco-bulbs that don't do squat what they say they s'posed to.
More positively, when are the results from the science project due? good luck with it too