Forum Discussion
insp1505
Oct 19, 2013Explorer
Skipro3-
I'm a little confused at the point you are trying to make? Are you implying that the skylight warped at a lower temperature than the temperature the thermometer read? Sure that's possible I guess. Does it really matter? The point is damage was done from heat provided by the hot summer sun. If the thermometer got that hot from the direct sun then didn't the plexiglass get just as hot in the same direct sun regardless of air temp?
I do understand objects become hotter in direct sunlight. That's really not the issue here though. The issue is that the heated object (the inner plexi-glass layer) wasn't allowed to cool or transfer heat off itself fast enough to avoid being damaged because I kept the shade closed which trapped the heat inside. The outer layer had the cooler outside air to transfer it's heat to so it didn't warp. The shade had the cooler inside of the camper to transfer it's heat to so it didn't get damaged either. Only the inner layer of plexiglass warped because it had a superheated air mass between it and the outer plexiglass layer and also between it and the shade that didn't transfer the heat away efficiently enough to keep the inner layer of plexi-glass from becoming too hot and warping.
Saying the only thing that got hot was the thermometer and not the air around it is just not true. Check into how solar ovens work, Dometic designed one, disguised it as a skylight for RV's and called it Heki. True, the direct radiant energy of the sun provided the heat energy to do the damage but the heated air between the shade and the inner layer of plexi as well as the heated air between the inner and outer layer of plexi-glass contributed to the damage. That air got so hot that it could no longer transfer enough heat energy off the inner layer of plexi-glass to keep it cool enough to prevent warping.
The air between the two layers of plexiglass will always get hot from being in direct contact with the plastic with no where to go and no where to transfer heat to other than back to the hot layers of plastic that heated this air in the first place. By keeping the shade open the air below the inner plexi-glass won't become as hot as if the shade were closed.Therefore this cooler air is able to absorb more heat energy from the inner plexiglass hopefully keeping it from becoming hot enough to be damaged. Because I kept the shade closed the air below the inner plexi became hot as well. As hot as the thermometer reading? Who knows? Who cares? It doesn't matter. It just became hot enough that it could no longer cool the inner layer of plexi-glass fast enough to prevent damage.
Yes, I could have made a little umbrella and shaded my thermometer probe if it mattered what the air temperature was in comparison to direct sunlight temperature was but it really doesn't. What ever the temperature of the thermometer or temperature of the trapped air happened to be is pointless other than knowing it was it was hot enough to assist with the damage. The important thing to know is that a Heki, in direct sunlight, with the shade pulled, becomes like a solar oven and traps enough heat energy to cause damage to the skylight which wasn't designed with good enough quality plastic to withstand it.
I'm a little confused at the point you are trying to make? Are you implying that the skylight warped at a lower temperature than the temperature the thermometer read? Sure that's possible I guess. Does it really matter? The point is damage was done from heat provided by the hot summer sun. If the thermometer got that hot from the direct sun then didn't the plexiglass get just as hot in the same direct sun regardless of air temp?
I do understand objects become hotter in direct sunlight. That's really not the issue here though. The issue is that the heated object (the inner plexi-glass layer) wasn't allowed to cool or transfer heat off itself fast enough to avoid being damaged because I kept the shade closed which trapped the heat inside. The outer layer had the cooler outside air to transfer it's heat to so it didn't warp. The shade had the cooler inside of the camper to transfer it's heat to so it didn't get damaged either. Only the inner layer of plexiglass warped because it had a superheated air mass between it and the outer plexiglass layer and also between it and the shade that didn't transfer the heat away efficiently enough to keep the inner layer of plexi-glass from becoming too hot and warping.
Saying the only thing that got hot was the thermometer and not the air around it is just not true. Check into how solar ovens work, Dometic designed one, disguised it as a skylight for RV's and called it Heki. True, the direct radiant energy of the sun provided the heat energy to do the damage but the heated air between the shade and the inner layer of plexi as well as the heated air between the inner and outer layer of plexi-glass contributed to the damage. That air got so hot that it could no longer transfer enough heat energy off the inner layer of plexi-glass to keep it cool enough to prevent warping.
The air between the two layers of plexiglass will always get hot from being in direct contact with the plastic with no where to go and no where to transfer heat to other than back to the hot layers of plastic that heated this air in the first place. By keeping the shade open the air below the inner plexi-glass won't become as hot as if the shade were closed.Therefore this cooler air is able to absorb more heat energy from the inner plexiglass hopefully keeping it from becoming hot enough to be damaged. Because I kept the shade closed the air below the inner plexi became hot as well. As hot as the thermometer reading? Who knows? Who cares? It doesn't matter. It just became hot enough that it could no longer cool the inner layer of plexi-glass fast enough to prevent damage.
Yes, I could have made a little umbrella and shaded my thermometer probe if it mattered what the air temperature was in comparison to direct sunlight temperature was but it really doesn't. What ever the temperature of the thermometer or temperature of the trapped air happened to be is pointless other than knowing it was it was hot enough to assist with the damage. The important thing to know is that a Heki, in direct sunlight, with the shade pulled, becomes like a solar oven and traps enough heat energy to cause damage to the skylight which wasn't designed with good enough quality plastic to withstand it.
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