Thermal Energy, Somthing to think about.

[Matthew Jones]

So I have been growing a lot food hear lately in fact I am making it my business. Organic Farming. So this year I decided to grow right through the winter. In the past I have grown in late fall early spring, but never through the new year.
Of course this year in NC we are setting record low temperatures. So I was researching how to get through them.

One thing I decided to do was put blankets over everything. The blankets protect down to 15 degrees or so with no wind. But last night we had 11 deg temperatures with wind chill drop of -5 deg f.

So I did the igloo thing and sprayed all the small row hoops and blankets with water and built up about 1/2 inch of ice over everything. And in the process of doing that I asked myself a question, mostly cause it was cold and I was wet but....

If by building an igloo out of snow, insulates and warms the air inside it too a comfortable 32 degrees F, Where does the heat come from and for how long

One rule of Thermal energy is HOT always goes to COLD. So with that in mind How long can that snow expel HEAT into the air to keep the temperature up. Cause even if we let some air in then close it off the air will warm back up to 32.
And if the ice is warming the air back up where is that energy coming from and for how long will energy last?

I didn't say we we're in the igloo and the ground inside is covered with snow so the ground is not warming, you are not warming, so where does the heat come from?

It was rough night. LOL

Matt

[Bob Smith]

I wonder if this is the case because water and ice absorb EM radiation, moreso than the air, with its lesser moisture content, around it.
A couple of interesting references (Wikipedia's not my favorite source of info, but this seems worth sharing):
Electromagnetic absorption by water - Wikipedia, the free encyclopedia
and
Properties of water - Wikipedia, the free encyclopedia
Hope all goes well with the crops.

[ewizard]

One thing I remember from college chemistry is that water holds more kilocalories of heat per Mole than any other substance. That may be relevant to your inquiry.

[DavidE]

Hmmm.

Matt,

To answer your questions... you will have to consider all surface area of your thermal barrier (whatever materials and their standing temp). Your ice would simply slow heat transfer (depending on inside and outside temp), but I wouldn't count on any "heating" effect.

Now snow on a roof takes advantage of trapping air and thus is quite a good insulator (much better than ice) from temperatures below freezing. But it still conducts heat energy at some level.

Now the question is, can you add mechanical heat energy to the equation once you have control of the barrier? Greenhouse's normally have huge amounts of cubic volume, so this can be difficult.

Also what is the minimum temperature that your plantings can survive?

In one of my prior lives, I worked in the residential housing industry producing high performance thermal shells. Homes that performed in the top 1% of all homes built in US.

There are creative ways to add heat energy... or take advantage of structure mass values. Not sure what you can take advantage of... don't hesitate to write me at davideperrin@gmail.com

If you like, we can exchange more specifics of your situation.

[Matthew Jones]

Hey David

At one time I designed and built homes as well. My home in fact at one time was one of the most efficient in the state. I am not sure where it stands now. I know quite a bit about structure. But thats not the topic.

Just an example, If you build an igloo in a snowy area in which the air temp is 0 deg f, and completely close it off with thermostat inside the air will go up to 32 deg f, AND STAY THERE, . This is a fact known for long time. The temp will go above 32 if you are in it. But your not.

So the question stands, How long can the snow continue to expel heat into the air without becoming colder? And where does that energy come from?

@Bob & Ewizard

Both are great answers.

Its head scratcher for sure.... I just posed the question to see what people would say. I couldn't find an definitive answer.
The whole thing makes you wonder because when we talk about heat we think in terms of burning hot heat. We never associate heat or HEAT ENERGY in a cold situation.
If I had the chance I would build a pile of snow or ice with hollow area in the middle, thick enough to insulate from the light of day just see if the temperature stayed at 32. But thank GOD I we are not getting snow this year.

Matt

[RAMSET]

enormous thermal mass

Mathew
the ground under that ice blanket must be around 50 degrees F at 6 inch depth [or higher]?

we ran an open well head for water in one of our commercial yards up in NY with just a blanket covering ,,it never froze even on the coldest nights [with out the usual drip running either]

the ground releases huge amounts of heat to the colder air, it has to be coming up from the earth and working its way out into a thermal bubble.

thx
Chet

[Matthew Jones]

Ya I understand that but in the post above yours is the igloo question. Read that. Thats what I was getting at.

Cheers
Matt

[DavidE]

Matt,

Sorry I screwed up your point. I actually thought you were trying to solve a problem with some new ideas.

But as you illustrated, you believe you already have the answer. I won't make the mistake with you again.

Good luck with your crop.

[Matthew Jones]

No I really don't have an answer. I was real curious if an answer would emerge. I believe that in a certain situation any number of things are possible an ice cube water in freezer set on 30 deg f will stay 32 degrees. So since its warmer than the air around it the heat from it must be discharged because heat must travel to cold, no exceptions. But no matter how much heat it expels it stays 32 degrees. Where's the energy coming from?

We wanna talk about Negative resistance, free energy, and dark matter, ect, ect. What the hell there is an unlimited amount of energy blocked up in our freezer. Maybe its no good till you drop in your glass but what the heck?

LOL See what I mean? Maybe not but its mystery to me. Either the rules are flawed or every ice cube in your fridge is a perpetual motion machine, creating energy to allow the environment to consume. LOL

Matt

[RAMSET]

not sure I understand

Mattew
are you saying you have checked ice cubes in the freezer and they are warmer then the freezer [cubes staying at 32F in a 0 F freezer?]?

I think a good freezer gets to 0 F

?
thx
Chet
ps
if thats the claim I will test this tonight out side it will be 0 F tonight here,I have a good test probe for this.

[Matthew Jones]

Good test it. I was going to barrow a meter of friend of mine. He's an AC man.

Let me know what you find.

Matt

##Just checked my freezer is set on 28. Whether that accurate or not...

[RAMSET]

Good thing I checked back

Ok I'm setting a cup of water out side tonight with the probe
I'll report back in the AM
have a good night
Chet

[RAMSET]

quite odd actually

Mathew
well the probe batteries were dead so I had to look around a bit for those 9v ones that love to hide ...and then they have the nerve to be dead when you find one...
the fire alarm gave up its usual always good 9V Bat inventory.

seems we;ll be playing here a bit tho

took a 10 inch tall by 2,5 inch wide tupperware cup filled it with well water centered the probe in the cup by placing a paper cup with a hole in the bottom center into the water [probe centering device]

That was last night

after I lit the fire this AM and remembered the Probe outside ambient had risen to 5 F probe was 17.9 F...
it was taking a very long time to go down [once I plugged it into the device]and my electronics on the device were getting less happy with the cold so I thought oh well no reason to freeze altogether during this test I'll just bring it into the house and see where ir levels off [ambient 65F]

made a cup a jo checked it [about 2minutes] 16 F
went down to the shop checked the fire came back up [3 min]
its at 25 F

I think I will play here some more
very odd very odd indeed ...the water seems to have learned some tricks to keep warm over the years....
perhaps it will teach us too .

thank you Mathew

Chet
PS
Just checked after posting [12 min]its at 31 F sitting inside the solid block of ice...

10.17 AM
after placing the container outside again at 31 F start temp 9.37 AM
temp holding at 29F in 8 F ambient

So it grabs the available heat quite rapidly thru atleast 1 inch radius solid ice annulus
when place inside [5 minutes to raise 9 F]
and when placed back outside into cold only looses 2 F in 20 min.

[Obvious big ambient desparity tho]

I will have to make a little chart for the data and test apparatus .
now I am a bit curious what that seeming Tunneling of the energy can have on a coil ?

[Matthew Jones]

Thats why I posted the question, cause there was no answer. Somewhere I am sure, text book or something but not easily accessed. Maybe even hidden.

I watched my plants last night under the frozen blanket. at 5:00 this morning it was 12 deg f outside and under the frozen blanket it was 24 deg f according the little thermostat I set under them, and the plants were placid. They usually get real rigid like frozen rigid at about 26 or below even under the blanket. The ground though was hard and frozen. But not the plants. So they obviously have some heat to a point.

I don't know its a funny thing for sure. I think the electromagnetic absorption of water (Linked to by BOB) plays into it for sure. Can't prove it though. Maybe more or something different when frozen.

Matt

[RAMSET]

worthless data

Mattew
Popped the ice annulus from the cup
somehow the probe worked its way from the center of the annulus to the bottom edge while freezing.

will make a better job of it tonight .

I am using a simple TES 1310 type - K
thermometer

will chart ambient as well as probe.


thx
Chet