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Re: air mattress tent & camping Urban Legends
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songbird
Oct 9, 2016, 7:58:03 PM10/9/16
to
zoe_lithoi wrote:
...
they make these neeto things called thermal pads
for camping which work great.
much lighter and take up less space plus you
don't need to pump them up much at all to get
them ready.
songbird
...
they make these neeto things called thermal pads
for camping which work great.
much lighter and take up less space plus you
don't need to pump them up much at all to get
them ready.
songbird
zoe_lithoi
Oct 9, 2016, 9:32:46 PM10/9/16
to
Hello songbird,
I believe the thermo pad you refer to is called by other names such as 'reusable chemical heat pack' or similar. When you activate these things, they give off heat for a certain amount of time.... though the manufacturers seem to hide this information. When you are done, you re-energize them by boiling them in water.
assuming I understand the product you refer to, my estimate for a 'thermo pad', then I estimate that it will give off 40 to 55 Btu/hr for 4 to 6 hours. Since a tea-candle produces 250Btu/hr for 4 hours, we would need about 5 of these thermo pads for a similar heat output.
I made my estimate from the information below.
Amazon has this information about what I suppose is a similar product "HEAT WAVE Instant Reusable Heat Pack - LARGE (8 x 12 inches) .... Product Dimensions: 18.1 x 5.9 x 0.8 inches ; 1.8 pounds"
I am not sure which dimensions are correct, but I'm going with the 1.8 pounds as a guidline. Heat Wave also doesn't give the energy storage information, however, now that we know how much it weighs, we can make some estimates...
"sodium acetate trihydrate has a large latent heat of fusion-crystallization is 264–289 kJ/kg and its melting temperature = 58degC"
--- page 155 'Thermal Energy Storage: Systems and Applications' By Ibrahim Dincer, Marc Rosen
280kj/kg x 0.95Btu/kj x 1kg/2.2lb x 1.8lb = 218btu
If this were spread out evenly over 4 hours, it would be:
218/4 = 55 Btu/hr
a tea-candle produces 250Btu/hr for 4 hours
Toby
I believe the thermo pad you refer to is called by other names such as 'reusable chemical heat pack' or similar. When you activate these things, they give off heat for a certain amount of time.... though the manufacturers seem to hide this information. When you are done, you re-energize them by boiling them in water.
assuming I understand the product you refer to, my estimate for a 'thermo pad', then I estimate that it will give off 40 to 55 Btu/hr for 4 to 6 hours. Since a tea-candle produces 250Btu/hr for 4 hours, we would need about 5 of these thermo pads for a similar heat output.
I made my estimate from the information below.
Amazon has this information about what I suppose is a similar product "HEAT WAVE Instant Reusable Heat Pack - LARGE (8 x 12 inches) .... Product Dimensions: 18.1 x 5.9 x 0.8 inches ; 1.8 pounds"
I am not sure which dimensions are correct, but I'm going with the 1.8 pounds as a guidline. Heat Wave also doesn't give the energy storage information, however, now that we know how much it weighs, we can make some estimates...
"sodium acetate trihydrate has a large latent heat of fusion-crystallization is 264–289 kJ/kg and its melting temperature = 58degC"
--- page 155 'Thermal Energy Storage: Systems and Applications' By Ibrahim Dincer, Marc Rosen
280kj/kg x 0.95Btu/kj x 1kg/2.2lb x 1.8lb = 218btu
If this were spread out evenly over 4 hours, it would be:
218/4 = 55 Btu/hr
a tea-candle produces 250Btu/hr for 4 hours
Toby
songbird
Oct 9, 2016, 10:05:16 PM10/9/16
to
zoe_lithoi wrote:
> Hello songbird,
>
> I believe the thermo pad you refer to is called by other names such as 'reusable chemical heat pack' or similar. When you activate these things, they give off heat for a certain amount of time.... though the manufacturers seem to hide this information. When you are done, you re-energize them by boiling them in water.
>
> assuming I understand the product you refer to, my estimate for a 'thermo pad', then I estimate that it will give off 40 to 55 Btu/hr for 4 to 6 hours. Since a tea-candle produces 250Btu/hr for 4 hours, we would need about 5 of these thermo pads for a similar heat output.
no, they are just insulated pads you can sleep on.
> Hello songbird,
>
> I believe the thermo pad you refer to is called by other names such as 'reusable chemical heat pack' or similar. When you activate these things, they give off heat for a certain amount of time.... though the manufacturers seem to hide this information. When you are done, you re-energize them by boiling them in water.
>
> assuming I understand the product you refer to, my estimate for a 'thermo pad', then I estimate that it will give off 40 to 55 Btu/hr for 4 to 6 hours. Since a tea-candle produces 250Btu/hr for 4 hours, we would need about 5 of these thermo pads for a similar heat output.
a foam cushion wrapped in a cover. holds some air
but is also insulated so it does not transmit cold
from the ground.
i think the one i have is Thermarest or something
like that. very nice and takes up much less space
inside a small tent than a thicker air mattress.
i've camped both ways, like the insulated pad
much better. :)
cheers,
songbird
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