# possible unexpected application of intense incan



## night.hoodie (Jun 19, 2018)

Anyone have an AC window unit with the face of the cooling coils more or less exposed on the inside of the window for air return?

I may be imagining this.

Especially if the ambient outdoor temperature is low, my window unit has a difficult time cooling inside (the idea in this case is not so much to cool, but to dry the air, when cool outside with high Relative Humidity). 

I have the strangest feeling I have rediscovered what military stationed domestically in subtropic regions and abroad in uncomfortably warm dry or wet environments, with Surefire incans, and window AC units installed in their temporary housing, had already discovered, out of boredom.

Little is as disappointing as when an AC unit is outmatched by the environment, and seems to barely make a dent in the indoor temperature or humidity. When I shine my Surefire incans at my cooling unit coils, it works better, immediately starts cooling and drying faster. More incan light, more and more better cooling. There is almost a runaway effect at some point, and with an incan flashlight, I seem to be able to coax my AC from barely making a dent into blessed cooling overdrive.

Am I delusional? Likely, but what do you think of that?


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## parametrek (Jun 19, 2018)

Seems too good to be true.

The classic 2xCR123A Surefire had 1 hour of runtime. 2xCR123A = 9.3Wh so there is an average power of 9.3 watts consumed by the flashlight. Let's assume that 100% of that energy is converted and radiated as photons. 2% visible and 98% IR but visible lumens don't matter here. In reality it would be somewhat less because some of that energy heats up the flashlight. Those photons (visible and IR) strike the coils of the AC. Assuming cheap galvanized coils, zinc has a reflectivity of about 70% across most of the visible and IR range. So 30% of the energy is absorbed by the coils.

The flashlight imparts about 3 watts of energy to the system. I'm still not sure which part of the system you are talking about though. Are you talking about a traditional compressor based unit or an evaporative swamp cooler for example? The compressor based AC units are actually kind of complicated because they need to both cool the air and dehumidify it and move both heat and water outside.

Overall though it seems to good to be true. The (compressor) AC units can consume 1000 watts easily. There are constantly tightening requirements to improve efficiency. If an extra 3 watts of energy could make a difference we'd probably already be doing it. Even if it didn't improve efficiency someone would do it so they could advertise that their AC is faster.

Assuming it is real I can imagine one way it could happen with compressor AC. If the AC unit was poorly designed then the cooling coils could ice up. As the air cools the water condenses onto the coils and if the coils are too cold then the water freezes. That layer of ice acts as an insulating blanket and the AC unit basically stops working.

But this requires a poorly designed AC that ices itself to death easily.

Anyway now the photons are striking ice instead of zinc. Water and ice are very good at absorbing long wave IR. For ice it is around 60% absorption for near IR and 95% for wavelengths longer than 1.5 microns. Almost all of the incan radiation will be absorbed if it hits ice. Maybe the incan is de-icing the coils. If it were then that would do it.

How much ice can 10 watts melt? The heat of fusion for ice is 334 joules per gram. 10 watts is conveniently equal to 10 joules per second. So 10W of energy can melt 0.03 grams of ice per second or 3.6 grams in 2 minutes.

While that doesn't sound like much it could make the difference. If the coil is a tube of 5mm diameter and 5 meters length it would have a surface area of about 0.08 square meters. 4 grams of ice would coat it to a depth of 0.05 mm and should provide an insulation R value of around 0.001. Though since the light is only illuminating 1 side of the tube it can melt through 2x the ice on that side.

Here's where I am stuck. Does adding R 0.001 really hurt things that much? I don't think it would. But on the other hand if you ever need to de-ice a very delicate piece of equipment then an incan is probably the best way to do it.

So some questions for you. What type of AC was it? How many watts of light were you using? Or just what models and we can figure it out from there. And how long did it take to have an effect?


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## markr6 (Jun 19, 2018)

As usual on CPF, I'm definitely not the smartest person in the room.


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## sgt253 (Jun 19, 2018)

markr6 said:


> As usual on CPF, I'm definitely not the smartest person in the room.



Holy Physics Batman! Neither am I...


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## id30209 (Jun 19, 2018)

markr6 said:


> As usual on CPF, I'm definitely not the smartest person in the room.



I'll take your quote as mine[emoji3][emoji3][emoji3]


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## StarHalo (Jun 19, 2018)

This sounds higher than I am right now..

You're dumping more heat onto a system designed to rid heat, so that will not make any part of it work better. If it were that simple, they'd just put the cooling coils on the outside where direct sunlight could hit them..


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## night.hoodie (Jun 19, 2018)

parametrek said:


> Seems too good to be true.
> 
> The classic 2xCR123A Surefire had 1 hour of runtime. 2xCR123A = 9.3Wh so there is an average power ...
> 
> So some questions for you. What type of AC was it? How many watts of light were you using? Or just what models and we can figure it out from there. And how long did it take to have an effect?



I love your analysis. Let me try to answer your questions.

Its a bottom of the line GE unit (I'd provide the precise model, but it has no label) with a compressor, but I believe it is somewhat of a hybrid compressor/swamp cooler. idk, but seems that on low settings, the compressor never turns on, yet it can still slightly cool. idk if such a thing exists.

idk how many watts, but you'll know. IMR hybrid Li-ion cell with Tads 1.2A 3.7V lamp.

The effect is nearly instantaneous, and increases over time, and increases with more light (say, a second identical light, or a third, all trained on the coils).

All I can offer in rebuttal is that I'm not sure you are adding a straw man to my claim (which is not to say anything is more efficient or using less energy, no breaking energy conservation, the laws of physics will be obeyed in this house!), which btw is entirely anecdotal and not scientific. I'm not exactly sure how compressor AC works! But I have some idea that it must have something to do with pv = nrt, and slight variances, and may include the different heat properties of different metals. If I can increase those variances even slightly, it might give the coils and compressor some edge, or some reason to work harder and cool more. Maybe this is helping sink the heat, little heat, little sink, more heat, more sink, metaphorically like periodically giving a free-spinning wheel an extra push. I have a healthy imagination.

Question for you (because idk). Ignoring ambient temperature, or all things being equal, do AC coils cool better when in direct sunlight? Or better in shade? All I am doing is adding a little sunlight in the shade.


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## night.hoodie (Jun 19, 2018)

StarHalo said:


> This sounds higher than I am right now..
> 
> You're dumping more heat onto a system designed to rid heat, so that will not make any part of it work better. If it were that simple, they'd just put the cooling coils on the outside where direct sunlight could hit them..



From what I can see, there are a small amount of coils inside and most of them are outside (low profile inside, large profile outside). How well does your AC cool when you set your thermostat on 78° when the ambient temperature is 72°? What if you could synthetically make your thermostat "believe" the ambient temperature is 85°? I don't believe what is occurring is as simple as you describe, but my physics-fu is not strong. With evaporative cooling, without the right ambient temperature, or heat added to the system, the system will only add heat to the wrong side of the partition. I know that AC can only work if the heat is taken from one side of a closed environment, and moved to outside that environment. I believe I must be tilting the differential by adding heat. IR light is strange, almost magical, in that it doesn't heat a transparent medium, like air or clear glass (and travels through vacuum of space!), but must strike something opaque, which in turn, heats a surrounding transparent medium like air. (Water, btw, only appears transparent in small quantity; it is actually blue.)

Some of you must have AC window units and intense directed incan light. No experiment is foolish. Have at it.


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## idleprocess (Jun 19, 2018)

Perhaps the light is shining on a thermometer, making the unit think that incoming air is warmer than it actually is, forcing the compressor to engage.


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## badtziscool (Jun 19, 2018)

idleprocess said:


> Perhaps the light is shining on a thermometer, making the unit think that incoming air is warmer than it actually is, forcing the compressor to engage.



Now that’s an idea. And to take it one step further. Maybe there’s some sort of sensor that senses the ambient light in the room. More light will make it assume there’s more sunlight entering in the room and this engages the compressor even more.


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## idleprocess (Jun 19, 2018)

night.hoodie said:


> I know that AC can only work if the heat is taken from one side of a closed environment, and moved to outside that environment.


Ultimately, air conditioning compressors move heat around - there is by necessity a hot side of the compressor and a cold side. It's why you can't air condition the house by leaving the refrigerator door open.

The trick is rapid expansion of gas, which produces a terrific negative temperature gradient. By allowing gas (refrigerant) to expand at a location convenient to your system - such as a coils over which you more air you wish to cool - the heat within that air is transferred to the refrigerant. Upon exiting the cold side coils, the now-warmer refrigerant moves to the hot side coils where air is forced over them to transfer the residual heat from inside air into an external environment. The refrigerant is then compressed again - adding _appreciable_ heat due to the physics of gas - and moves towards the expansion point right before the coils.

Because air conditioning as we know it just moves heat around, it takes markedly less energy to cool a given space by X degrees than it does to heat it by X degrees. I believe that even middling air conditioning systems have performance coefficients of 2-3 - moving 2-3 units of heat for every single unit of equivalent energy they consume. Solid-state refrigeration - i.e. Peltier devices - are the inverse with performance coefficients closer to 0.2, producing small negative gradients on the cold side and terrifically high temperatures on the hot side.

As you likely know, cooling air causes condensation. Air conditioning systems are designed to remove this condensation from the air stream before sending the cool air into the room. Central air conditioning systems have draining pans that go into the sewer. Window units have historically dumped it to the outside environment. Newer portable units - already at a disadvantage due to their packaging _(even dual-hose models)_ have opted to up their efficiency a tad - and greatly reduce the need for users to drain them - by running condensation over the hot side coils to remove some of the heat then exhausting the condensation to the outside with the air blowing over the hot side coils.

I mention this because you've indicated that you have a 'hybrid' AC/dehumidifier which could use the same concept.

I'm still of the opinion that shining a light on the coils is simply doing something to trigger compressor engagement. Producing a low gradient is an easier *ask* than producing a high one since it doesn't have to work as hard or run as long. If you set it to 72 and it's 75 inside the room, the thermometer may well legitimately read 72 thus the fan simply runs to circulate air.

A _much_ less likely explanation is that since you're shining light on inside coils - which are most likely to be the cold side - you're adding some heat to the overall system, again tricking the controls.

But heating the thermometer itself is far more likely. I have a window unit in the master bedroom and the thermometer is plainly visible right behind the filter on the cold side intake. I used to have an ... _eccentric and ill-advised_ ... means of transporting the cold air from that window unit to the office on the other side of the house via a too-small flex duct - _with a booster fan in the middle *and* at the end_! I knew the window unit had frozen up when the cold air stopped arriving - the thermostat mercifully cut off the compressor before too much ice had a chance to form.

EDIT: It's worth noting that most air conditioning systems that I'm aware of - be it window units, central air, automotive - effectively only run at one 'setting', which is 'on'. Window units and automotive systems kind of mask this by running the fan continuously while the compressor cycles on and off; the control scheme relies on a certain thermal inertia on the cold side to maintain the felt illusion of continuous temperature coming out of the vents. Central AC relies more on the thermal inertia of the larger volume of air inside an entire structure with the entirety of the system switching on and off based on a control scheme - oftentimes PID to minimize chasing set points with short on/off periods. As such, it's hard to imagine that the introduction of a few watts of radiant IR energy onto the cold side coils is going to do anything to the thermodynamic fundamentals of a system that operates at a minimum of hundreds of watts.


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## bykfixer (Jun 20, 2018)

Well if nothing else we've been schooled on the basics of an air conditioner.


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## vadimax (Jun 20, 2018)

I am not an expert in the area, but I work in the nearest vicinity of a server room. And every time a conditioner has its heat exchanger covered with ice means only one — its coolant pressure is below normal. The only treatment — calling a service to perform a qualified refill. No exceptions encountered so far.

If you have to do that procedure too often — your coolant system is not sealed properly and you again need a serviceman with special equipment to locate the leakage spot.


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## ampdude (Jun 22, 2018)

night.hoodie, is it possible you simply have an A/C unit with too many BTU's for your square footage? An A/C unit that has too many BTU's for the square footage will cool the air, but fail to dehumidify properly as the compressor will not engage as often, causing the conditions you describe.

If those coils are heated up by an artificial source, the compressor will engage again as the A/C unit thinks the inside temperature is more than it really is, causing proper dehumidifying to occur.

I just bought $18 can of coolant at the store the other day to recharge one of my vehicles. Worth every penny, gotta have my A/C.


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## vadimax (Jun 24, 2018)

I am sorry, but A/C cannot “feel” heat exchanger temperature change. Purely because it has no temperature sensor there.


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## Kiwi123 (Aug 13, 2018)

Assuming it is real i can imagine one way it could happen with compressor AC, if the AC unit was poorly designed then the cooling coils could ice up, that layer of ice acts as an insulating blanket and the AC unit basically stops working...


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## night.hoodie (Aug 13, 2018)

All I know, from daily experience during this Summer... this window unit works far better, blows far colder, drys air better, when the ambient outdoor temperature is warmer, especially when sunlight is directy hitting the outdoor coils. I cannot determine if there is icing. As the ambient outdoor temperature drops in the evenings towards sunrise, the window unit does not blow as cold. Thus, that room is far colder at 3PM than it is at 4AM, even though the ambient temperature outdoors at 3PM might be 95°F and at 4AM might be 73°F. 

These experiences are apparantly anomalous? If the reason why this would be can be revealed, beyond icing which I see no evidence of, then it would explain why shining intense incan light at the coils from inside might cause the unit to blow colder.


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## mickb (Aug 15, 2018)

night.hoodie said:


> I have the strangest feeling I have rediscovered what military stationed domestically in subtropic regions and abroad in uncomfortably warm dry or wet environments, with Surefire incans, and window AC units installed in their temporary housing, had already discovered, out of boredom.



I spent 25 years in the professions and regions your second paragraph refers to and have never heard anything like it, from any soldier nor any army I have worked alongside( which would be over 20) . Sitting here even now in the tropics with 3 window AC units to my house I see no effect from an incan light, nor would I expect to. 

Lets be honest. Do you realise if this worked people would have been on to it 100 years ago. It would revolutionise science and engineering if an infintessimal output of a small light shining on cooling fins caused a dramatic improvement in cooling efficiency.If you are really experiencing this phenomenon you need to market it and get your name alongside Tesla and Edison.


But is this a serious thread though? Possibly I am missing some joke here the OP is having.


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## night.hoodie (Aug 15, 2018)

I have a detailed imagination regarding what bored military do. 

The claim I make does not make sense to me either. I didn't claim it was more efficient or breaking energy conservation laws, only that the unit begins to blow colder when I am adding negligible heat (from intense incan light) to the coils. 

My suggestion is only that there may be atmospheric conditions which allow the unit to make air blow colder than during times with different atmospheric conditions. The hotter and dryer it is outside, especially when sunlight is beating on the outdoor coils, unit seems to blow much colder. 

The way ambient temperature feels is very subjective. We can become acclimated to 93°F in a way that 75° feels too cool to be comfortable, when it almost seems universal that most agree 62°F is the right amount of cool.

I honestly have no explanation that makes sense, which is why I posted. I could be imagining the effect, but I do not think so: it is more or less as I describe, adding heat to the coils makes the unit blow colder, the warmer it is outside, the colder it gets inside.


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## mickb (Aug 15, 2018)

night.hoodie said:


> I have a detailed imagination regarding what bored military do.



If you can imagine soldiers, fighter pilots, SF, SWAT, military trade and technical staff in the 'subtropics' clustered around an AC in the middle of the day shining their EDC and weapon lights at it to see if it works better, your imagination needs less details more reality. No offence but no military are going to burn up batteries in equipment which saves their and will often have to replace at own expense if they waste it running experiments which don't make sense.


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## night.hoodie (Aug 15, 2018)

mickb said:


> If you can imagine soldiers, fighter pilots, SF, SWAT, military trade and technical staff in the 'subtropics' clustered around an AC in the middle of the day shining their EDC and weapon lights at it to see if it works better, your imagination needs less details more reality. No offence but no military are going to burn up batteries in equipment which saves their and will often have to replace at own expense if they waste it running experiments which don't make sense.



Absolutely none taken, and likewise no disrespect meant, it was an absurd notion.


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## StarHalo (Aug 15, 2018)

Just get an IR thermometer gun and take a reading of the interior grill after the unit has been running ~five minutes 1) in the middle of the day, and 2) in the middle of the night.


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## LuxLuthor (Aug 29, 2018)

I recommend cutting back on the acid dose.


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## night.hoodie (Aug 29, 2018)

LuxLuthor said:


> I recommend cutting back on the acid dose.



Far out! That is one righteous burn, boss! :rock:


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