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Post by icefisher on Aug 25, 2013 0:04:40 GMT
Firstly the temperature affect due to water misted into low humidity air is a red herring that's related to vapor pressures etc. A whole new discussion. Release of energy is what happens when there is a temperature delta. The falling temperature item sheds energy, (release) I entirely agree as we see latent energy released from water at freezing it only shows itself as a temperature buffer so flatlining the temperature at freezing point but no clouds of heat. A cooling environment supports a temperature inversion and it must be strong and active to avoid the loss of the formed temperature gradient as wind and diffusion is constantly eating into it. So even if the source of heat for directly warming the air is not from the ice the air warms anyway by the consist input of diffusion and winds from higher level air. In fact the arctic in the dark has a permanent inversion as it is always cooling from heat arriving at the surface by diffusion, radiation, and winds from upper level airs that blow in as part of the large convection cells. So anytime you slow down cooling you do damage to the inversion temperature gradient and that results in warming. So the issue of the direct fate of latent heat isn't relevant to whether the freezing of ice warms the air. But simply saying that the release of latent heat is controlled by radiative cooling doesn't make that true either. Work was required to loosen the molecules to make the water liquid. There is a natural force trying to push it back out that only the kinetic energy of the molecule prevents. Whether that force can accelerate the release of heat or not is a topic of careful scientific examination, not arm waving. The only point I made is that if water and earth is pretty much cooling in lockstep and the water stops cooling it becomes a better source of energy for a machine to apply work to warm your house than extracting energy from a colder source. If one has enough water as shown in the University of Florida growing experiments one can get heat out of this process either directly or indirectly. One thing is for sure is if I want to build the best igloo, I am not going to hire Numno but go find somebody like an eskimo who hopefully still knows how to build them better. But that might be a lost art as it seems they all now live in plywood buildings they don't have to rebuild every year and burn imported fuel to stay warm instead
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Post by magellan on Aug 25, 2013 0:10:22 GMT
Freezing of water is a release of heat. No dead body required. Before digging your hole deeper arguing with a farmer, you probably should have done a bit more reading on the subject. Well, I have lived surrounded by freezing and melting water all my life, and I can guarantee there is absolutely no change in temperature when everything freezes up around me! No puffs of warm air, no puffs of cold air, just the same 0C! Show me the free energy from freezing! Any video will do, but, there has to be a thermometer that rises when something freezes close to it! And I must add I'm not expecting any to show up! Sure Numo, farmers are so stupid. Do rain drops freeze from the inside out or outside in?
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Post by numerouno on Aug 25, 2013 0:53:23 GMT
Is there a thermometer that is going up with warm air emanating when there is freezing going on in any of the the videos? Please give me a heads up when you see one.
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Post by magellan on Aug 25, 2013 1:39:25 GMT
Is there a thermometer that is going up with warm air emanating when there is freezing going on in any of the the videos? Please give me a heads up when you see one. Do raindrops freeze from the inside out or outside in? The process of frost protection using water to form ice on the plants is well known and used widely according to what I've read. As I understand it they continue the process throughout the night and turn off the sprayers when the ambient temperature (wet bulb) is such that the ice melts on the plants. Let us revisit what you said (my bold): You have the search link, a published paper and the video from 3 farmers explaining it so even a 3rd grader can understand.
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Post by icefisher on Aug 25, 2013 1:41:25 GMT
Is there a thermometer that is going up with warm air emanating when there is freezing going on in any of the the videos? Please give me a heads up when you see one. Your wish is my command!
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Post by numerouno on Aug 25, 2013 1:57:35 GMT
Water was supercooled in the video.
We are not dealing with this kind of water, but ordinary water.
The search will continue.
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Post by icefisher on Aug 25, 2013 2:17:53 GMT
Water was supercooled in the video. We are not dealing with this kind of water, but ordinary water. The search will continue. And of course it must be your contention that ice is always formed in the Arctic right at 0C right? LOL! It might be worthwhile to look again at the DMI graphic where the temperature had dropped a bit below -2C and the spike shows it warming to about -1C, just like in the demonstration in the video. this is video proof of the heat you claimed could never be observed, yet you are observing it.
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Post by sigurdur on Aug 25, 2013 3:49:15 GMT
The plants are the thermometer. No calibration needed. -2C dry bulb and no frost damage. Shut off the sprinkler. The plants die because they get too cold. Simple but effective thermometer.
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Post by Andrew on Aug 25, 2013 4:59:01 GMT
The plants are the thermometer. No calibration needed. -2C dry bulb and no frost damage. Shut off the sprinkler. The plants die because they get too cold. Simple but effective thermometer. come on you can do better than that. Warm water is being applied to the plants. The latent heat of fusion enables a delay in cooling below 0C, meanwhile a new layer of ice builds so that it becomes impossible for the plants to cool to very cold space or to the cold air due to a layer of relatively warm ice that surrounds the delicate plant. These guys are continually dumping water warmed by the warm deeper ground onto a surface that is cooling because of the presence of a cold surface somewhere. Obviously the warm surface they are creating is going to act against the cooling ability of the other colder surfaces. Additionally damaging frosts that this system can protect against happen on dry still nights. With warm water being sprayed the entire area is now warmer and more humid and there is a poor ability for that humidity to be removed because there is little wind
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Post by icefisher on Aug 25, 2013 5:17:13 GMT
The plants are the thermometer. No calibration needed. -2C dry bulb and no frost damage. Shut off the sprinkler. The plants die because they get too cold. Simple but effective thermometer. come on you can do better than that. Warm water is being applied to the plants. The latent heat of fusion enables a delay in cooling below 0C, meanwhile a new layer of ice builds so that it becomes impossible for the plants to cool to very cold space or to the cold air due to a layer of relatively warm ice that surrounds the delicate plant. Not quite Iceskater! Ice is more conductive than air. And nothing prevents the ice from getting colder. They have to continuously keep the ice warm by spraying water and getting continuous heat from the warmer water and the heat of fusion to maintain the temperature of the ice at zero. In fact several of the videos discuss this. And its discussed in the paper from the Univ of Florida I gave you. They also have to run the water until like 9AM. The reason is if the ice is allowed to melt normally that will damage the blossoms also. They must keep spraying until temperatures rise to about 40 degrees. I haven't heard the exact details on this but it must be to prevent sublimation from cooling the ice further.
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Post by Andrew on Aug 25, 2013 5:51:34 GMT
come on you can do better than that. Warm water is being applied to the plants. The latent heat of fusion enables a delay in cooling below 0C, meanwhile a new layer of ice builds so that it becomes impossible for the plants to cool to very cold space or to the cold air due to a layer of relatively warm ice that surrounds the delicate plant. Not quite Iceskater! Ice is more conductive than air. And nothing prevents the ice from getting colder. They have to continuously keep the ice warm by spraying water and getting continuous heat from the warmer water and the heat of fusion to maintain the temperature of the ice at zero. In fact several of the videos discuss this. And its discussed in the paper from the Univ of Florida I gave you. They also have to run the water until like 9AM. The reason is if the ice is allowed to melt normally that will damage the blossoms also. They must keep spraying until temperatures rise to about 40 degrees. I haven't heard the exact details on this but it must be to prevent sublimation from cooling the ice further. Evaporation from wet ice into a dry atmosphere will cool the ice. Nothing prevents the ice from getting colder??? they are spraying warm water on the ice. Where the latent heat of fusion provides hidden BTUs that must be consumed before the water can be cooled to be below 0C
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Post by magellan on Aug 25, 2013 6:06:41 GMT
come on you can do better than that. Warm water is being applied to the plants. The latent heat of fusion enables a delay in cooling below 0C, meanwhile a new layer of ice builds so that it becomes impossible for the plants to cool to very cold space or to the cold air due to a layer of relatively warm ice that surrounds the delicate plant. Not quite Iceskater! Ice is more conductive than air. And nothing prevents the ice from getting colder. They have to continuously keep the ice warm by spraying water and getting continuous heat from the warmer water and the heat of fusion to maintain the temperature of the ice at zero. In fact several of the videos discuss this. And its discussed in the paper from the Univ of Florida I gave you. They also have to run the water until like 9AM. The reason is if the ice is allowed to melt normally that will damage the blossoms also. They must keep spraying until temperatures rise to about 40 degrees. I haven't heard the exact details on this but it must be to prevent sublimation from cooling the ice further. The wet bulb temperature determines when the sprinkler is turned on and off. It is explained well in this paper, possibly the same one you mentioned. biomet.ucdavis.edu/frostprotection/Principles%20of%20Frost%20Protection/PFPshort/PFPshort.pdfThere is no reason for Numo and his partner to drag this on. These guys could make baking a potato a major scientific mystery.
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Post by sigurdur on Aug 25, 2013 6:45:16 GMT
come on you can do better than that. Warm water is being applied to the plants. The latent heat of fusion enables a delay in cooling below 0C, meanwhile a new layer of ice builds so that it becomes impossible for the plants to cool to very cold space or to the cold air due to a layer of relatively warm ice that surrounds the delicate plant. Not quite Iceskater! Ice is more conductive than air. And nothing prevents the ice from getting colder. They have to continuously keep the ice warm by spraying water and getting continuous heat from the warmer water and the heat of fusion to maintain the temperature of the ice at zero. In fact several of the videos discuss this. And its discussed in the paper from the Univ of Florida I gave you. They also have to run the water until like 9AM. The reason is if the ice is allowed to melt normally that will damage the blossoms also. They must keep spraying until temperatures rise to about 40 degrees. I haven't heard the exact details on this but it must be to prevent sublimation from cooling the ice further. Icefisher: When the ice melts it extracts heat from the plants and will freeze them. You are on the correct track in that application of water is continued until the ice melts off via higher air temp. I can't do the math to show why this happens. I know what happens if this is not done. The plants will freeze at 33f.
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Post by sigurdur on Aug 25, 2013 6:48:25 GMT
Iceskater: The small amount of heat in the liquid water wouldn't do squat as far as warming.
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Post by Andrew on Aug 25, 2013 6:56:00 GMT
Not quite Iceskater! Ice is more conductive than air. And nothing prevents the ice from getting colder. They have to continuously keep the ice warm by spraying water and getting continuous heat from the warmer water and the heat of fusion to maintain the temperature of the ice at zero. In fact several of the videos discuss this. And its discussed in the paper from the Univ of Florida I gave you. They also have to run the water until like 9AM. The reason is if the ice is allowed to melt normally that will damage the blossoms also. They must keep spraying until temperatures rise to about 40 degrees. I haven't heard the exact details on this but it must be to prevent sublimation from cooling the ice further. Icefisher: When the ice melts it extracts heat from the plants and will freeze them. You are on the correct track in that application of water is continued until the ice melts off via higher air temp. I can't do the math to show why this happens. I know what happens if this is not done. The plants will freeze at 33f. The air temperature above the surface layers where the thermometers are present will be tens of degrees colder. The ice can therefore radiate thru the warm dry air to the colder layers so that the ice becomes damagingly cold. Only when the local air temperature is sufficiently warmer than ice that it can conduct and radiate more energy to the colder ice than the ice can radiate to much colder surfaces elsewhere will the ice begin melting. In dry places like Florida and Arizona you can freeze water when the dry still atmosphere is about 7-12? degrees warmer than the surface the ice builds on. The same principle was used by the ancients to create ice and it is still used today in parts of India where an insulating mat is laid on the warm ground and a pond of water is continually skimmed as the ice builds in the relatively warm dry night time atmosphere
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