McMooney Posted April 27, 2021 Report Share Posted April 27, 2021 I"m thinking this might just work in the Mooney, power draw doesn't seem to be outrageous. Plus would only need for takeoff and landing. all else fails use it when i go fishing Mark 2 Specs (zerobreeze.com) Quote Link to comment Share on other sites More sharing options...
Oscar Avalle Posted April 27, 2021 Report Share Posted April 27, 2021 I"m thinking this might just work in the Mooney, power draw doesn't seem to be outrageous. Plus would only need for takeoff and landing. all else fails use it when i go fishing Mark 2 Specs (zerobreeze.com)It works ok. The Limitation is that it needs a place where the compressor can push the air to the outside. Without that outlet it can’t really cool the air so well. But it is a cool unit...Also, it has its own battery so no issue there OscarSent from my iPhone using Tapatalk Pro Quote Link to comment Share on other sites More sharing options...
A64Pilot Posted April 27, 2021 Report Share Posted April 27, 2021 (edited) None of those really cool much. it’s simply a matter of physics. to get any real cooling requires lots of power, plus as has been said if you don’t have a way to get rid of the heat, then actually your heating the area. ‘Many of them work off of the Peltier principle and if they do, then they are horribly inefficient and don’t really provide much cooling at all. An example of a Peltier cooler is one of those Coleman coolers you plug into the cigarette lighter, and if you keep them out of the sun, they may get your drinks down to 60f or so. What really does work and works well for about 30 min is one of the coolers you fill with ice that pumps water through a transmission cooler and has a fan blow air over it. Big and heavy but until the ice melts they really do cool, because they work well, they will melt a whole cooler of ice in about 30 min. I’ve never seen any of these small coolers ever quote a BTU number, often they will tell you how many CFM the fan blows, but never seem to tell you how much cooling there is. Edited April 27, 2021 by A64Pilot Quote Link to comment Share on other sites More sharing options...
RLCarter Posted April 27, 2021 Report Share Posted April 27, 2021 Unless they have changed drastically over the 1st generation they won’t drop the temp at all. I tried one by placing it in my E and venting the exhaust outside (which you can’t do in flight). I opened both the cabin and baggage doors to air out the cabin while it was inside my hangar the closed it all up and let it run for over an hour and never got the temp to drop even one degree. They do blow cool air and considered plumbing it into the overhead vents but decided it wasn’t worth the trouble Quote Link to comment Share on other sites More sharing options...
hypertech Posted April 27, 2021 Report Share Posted April 27, 2021 bkool and a bag of ice will get you meaningful cooling for taxi and climb out. And by meaningful I bet like 10 degrees - its not a cold AC. If you want real AC, Kelly Aerospace will sell you one. 2 Quote Link to comment Share on other sites More sharing options...
jaylw314 Posted April 28, 2021 Report Share Posted April 28, 2021 Interesting. The suggestion from the bumpf is that it uses a compressor, so it's not just a peltier type cooler. I couldn't find numbers (always worrying), but suggested 400-600W power draw, which means you can forget using aircraft power. As noted above, you'd need a way to vent the hot air outside. Quote Link to comment Share on other sites More sharing options...
carusoam Posted April 28, 2021 Report Share Posted April 28, 2021 There is an annual thread around here of similar devices... Find the B-Kool thread and compare... the B-Kool is a real cooling device... portable and used often around here... If it is more compact than an automotive heater core.... something isn’t going to work as well as expected... If it doesn’t mention tens of thousands of BTUs... something is being hidden... If it looks like a battery powered hair dryer... with a cold button.... call it too good to be true... PP thoughts only... -a- 1 Quote Link to comment Share on other sites More sharing options...
carusoam Posted April 28, 2021 Report Share Posted April 28, 2021 This is the part of the site that gives a tech hint of what it can do... https://www.zerobreeze.com/pages/mark2-design-technical Looks like a mini window AC unit... Essentially it is too small to cool a whole cabin... Kind of complex to handle the warm air it generates... Put it in the too good to be true file... Using it while going fishing... sounds like the only way this will get used... unfortunately... Make sure you know where the warm air and moisture are going to get dumped... Best regards, -a- Quote Link to comment Share on other sites More sharing options...
Will.iam Posted April 28, 2021 Report Share Posted April 28, 2021 Site states 2300BTUs and uses a compressor so from the initial snap reaction crowd that didn’t even bother to look at the tech specs and assumed it was a peitier type cooler and no BTUs were stated, doesn’t help the OP one bit as you assumed it was a type of device that this product is not. Now is 2300 BTUs enough? I haven’t a clue and that’s if you could dump the hot exhaust overboard as well as the water it will produce so that rules out in flight. Unless you use jose’s pee tube to dump both? 3 Quote Link to comment Share on other sites More sharing options...
A64Pilot Posted April 28, 2021 Report Share Posted April 28, 2021 (edited) Well here is the site the OP linked to https://www.zerobreeze.com/pages/mark2-specs ‘I don’t see where it says BTU, and I never said it was a Peltier plate, I said many are, and those that are are essentially worthless. ‘However 2300 BTU isn’t bad at all, smallest window unit AC I’ve seen was 5,000 for example. ‘I’ve got quite a bit of experience through others with these “miracle” battery powered airconditioners with people with sailboats, everybody wants something that can get them through a hot night, or at least cool the cabin down enough to get to sleep, and unfortunately it just doesn’t exist, Airconditioning on a boat requires a generator at some time. Average smallest window unit AC (5,000 BTU) pulls after start up about 6 amps at 120 VAC, that’s about 720 Watts and that’s just under 1 HP, and that’s a LOT of power. Sure it can be decreased some by using expensive components, but not by much. ‘It’s also 60 amps at 12V, which is of course is everything a lot of our alternators are capable of producing, for a battery to supply 60 amps and not be real heavy and or real expensive for any amount of time would be real impressive. But this unit is 2300 BTU, so “only” half that, but 2300 BTU still takes serious power, 30 amps at 12V, which isn’t trivial at all, maybe 25 or so is realistic ‘Of all the small compressors available the Danfoss type has been the best for a very long time both from a service and from an efficiency standpoint, they get there by being brushless DC, which means among other things that they can be variable speed. All of the new house type AC’s, refrigerators etc that advertise they are ”inverter”units are actually brushless DC, because that’s how brushless DC motors work, and they can be more efficient, just not a whole lot. https://www.danfoss.com/en-us/products/dcs/compressors/compressors-for-refrigeration/direct-current-compressors/#tab-overview Recently Sawafugi developed a neat new tiny compressor, they call it a swing motor, it’s fascinating in its simplisticty, it’s just a piston and a spring that’s actuated by an electromagnet for the compression stroke, and the springs do the intake, then select springs who’s natural frequency corresponds to the RPM of the compressor and your compressing a gas without an electric motor and crankshaft etc. Real neat, but unfortunately it’s not more efficient than the Danfoss. But lots less moving parts and may last a very long time, bu sealed compressors like the Danfoss often run for 90,000 hours or more, so that’s tough to beat. https://www.sawafuji.co.jp/en/technology/swing_motor/ The bottom line is that unless or until there there is a large breakthrough in efficiency like LED’s were for instance in lighting, that effective airconditioning in small lightweight units, especially battery powered ones just isn’t possible. Still I’m impressed with 2300 BTU out of a 17 lb unit, but have to wonder about battery weight and expense as well as run time, because 2300 BTU takes quite a bit of power. Portable small airconditioners, especially battery powered ones are very similar to an electric airplane. It’s possible I guess, just not with current technology Edited April 28, 2021 by A64Pilot 1 Quote Link to comment Share on other sites More sharing options...
A64Pilot Posted April 28, 2021 Report Share Posted April 28, 2021 (edited) Oh, and you need two air ducts, one to suck air in and one to blow it out, both could be combined of course, but maintain separate hoses , the condensate drain could go with the air out. Some of the less expensive portable house units will only have one hose, that blows the heated condenser air out, they should be avoided because they pull air from the cooled area to blow outside and of course hot air from outside will find its way into the cooled area to replace it, the two hose units thst use outside air to cool the condenser are much better. ‘Many AC’s to increase efficiency actually will blow the condensate over the evaporator to help cool it, and that works well. Even some window units if you look at them the condenser fan will often have a ring around the end of the blades, this ring will pickup condensate water and sling it over the condenser, and help remove the heat. ‘The AH-64A’s air charge cooler would blow its condensate over the heat exchangers to cool them and it really increased cooling, not so much in the desert when there is no condensate though. The D model went to dual 7.25 ton AC’s to cool the aircraft. That’s 174,000 BTU, but it’s cooling a lot of avionics too. Cooling an aircraft is tough, even tougher than a car, due to solar heat gain and our large windows. For example the Zee airconditioning used in the Ag plane I used to build used If memory is correct is a 2 ton system, a 2 ton system is of course 24,000 BTU and will cool a small house, but it takes all of it to keep a single cockpit crop duster cool, but crop dusters operate down low in the heat and often during the hotter parts of the day. And again if memory is correct from the electrical load analysis, it pulls about 100 amps at 28VDC too, but that’s just from memory. Edited April 28, 2021 by A64Pilot Quote Link to comment Share on other sites More sharing options...
LANCECASPER Posted April 28, 2021 Report Share Posted April 28, 2021 Next month I'm finishing up the details with my mechanic for a 50 pound portable AC - it's brutal in Texas in the summer. Not cheap (+/- $5000), but will be easily detachable. The avionics shop ran the power and control wires back to the baggage compartment during my upgrade a few months ago. My IA is going to cut the holes in the baggage compartment, ducting the hot air to the tail section and the small hole will run the condensation to the back and out the belly where the older type vented batteries were previously vented. I bought a couple of extra tail inspection panels where we will have louvers to exhaust the air. (The original panels can easily be put back on to satisfy any future mechanics or owners.) It can run off an extra battery or ship's power (I have two 70 amp alternators) or both battery and ship's power. Here's a discussion of it: https://www.beechtalk.com/forums/viewtopic.php?f=52&t=180521 Quote Link to comment Share on other sites More sharing options...
A64Pilot Posted April 28, 2021 Report Share Posted April 28, 2021 Interesting. ‘My belief is that an electric system would be preferable, because if done right, the airplane could be cooled down while in the hanger and out of the sun, and the initial cool down is of course tough, real tough. Think of how little AC your car needs after it’s cooled down, compared to getting into a hot car. Tell us how well it works, I believe it has a good chance if the airplane can be pre-cooled 1 Quote Link to comment Share on other sites More sharing options...
Skates97 Posted April 28, 2021 Report Share Posted April 28, 2021 16 hours ago, A64Pilot said: None of those really cool much. it’s simply a matter of physics. to get any real cooling requires lots of power, plus as has been said if you don’t have a way to get rid of the heat, then actually your heating the area. ‘Many of them work off of the Peltier principle and if they do, then they are horribly inefficient and don’t really provide much cooling at all. An example of a Peltier cooler is one of those Coleman coolers you plug into the cigarette lighter, and if you keep them out of the sun, they may get your drinks down to 60f or so. What really does work and works well for about 30 min is one of the coolers you fill with ice that pumps water through a transmission cooler and has a fan blow air over it. Big and heavy but until the ice melts they really do cool, because they work well, they will melt a whole cooler of ice in about 30 min. I’ve never seen any of these small coolers ever quote a BTU number, often they will tell you how many CFM the fan blows, but never seem to tell you how much cooling there is. My home made one will cool air for a couple hours with a 20 lb bag of ice in it, I've used it on a two hour flight back to SoCal from Phoenix in the summer. The trick is having a lower flow sump pump so you aren't circulating the water as much. If you like do it yourself projects it is a fun one. https://intothesky.com/homemade-ac/ 2 Quote Link to comment Share on other sites More sharing options...
EricJ Posted April 28, 2021 Report Share Posted April 28, 2021 I still think a B-Kool or a home-brew like Skates' is far superior to the a/c units. Quote Link to comment Share on other sites More sharing options...
A64Pilot Posted April 28, 2021 Report Share Posted April 28, 2021 We built 24 of these for a customer, initially they went with the exhaust stacks off of a King air because they look cool and many believe that there is significant thrust form the exhaust. This one had our standard exhaust which threw the exh gasses straight out. ‘Anyway with that exhaust the doors had to stay shut or CO and just plain old sulphur would burn you eyes, customer was going to supply their own AC which was good because ours woudn’t cut it,not where they were going. ‘So I ordered one of those coolers from AC Spruce, it did amazingly well. but would go though a whole cooler full of ice in about 30 mins. We strapped it in the back seat and just kept refilling it. There is a tremendous amount of energy in heat Quote Link to comment Share on other sites More sharing options...
EricJ Posted April 28, 2021 Report Share Posted April 28, 2021 2 hours ago, A64Pilot said: ‘So I ordered one of those coolers from AC Spruce, it did amazingly well. but would go though a whole cooler full of ice in about 30 mins. We strapped it in the back seat and just kept refilling it. There is a tremendous amount of energy in heat Ice cools better, i.e., throws colder air, but freeze packs last a lot longer. I stuff a bunch of freeze packs in it and then put as much ice around them as will fit, and that lasts hours in the summer in Phoenix. You usually only need them for takeoff and landing, anyway, so for me they're more than I need. I've not run one completely out of capacity yet. Quote Link to comment Share on other sites More sharing options...
carusoam Posted April 29, 2021 Report Share Posted April 29, 2021 23 hours ago, Will.iam said: Site states 2300BTUs and uses a compressor so from the initial snap reaction crowd that didn’t even bother to look at the tech specs and assumed it was a peitier type cooler and no BTUs were stated, doesn’t help the OP one bit as you assumed it was a type of device that this product is not. Now is 2300 BTUs enough? I haven’t a clue and that’s if you could dump the hot exhaust overboard as well as the water it will produce so that rules out in flight. Unless you use jose’s pee tube to dump both? Are you trying to insult the MSers for trying to help with things they aren’t experts at? Or just poking at people because they didn’t do the homework for the OP? Prize winning post... You have made A64 look like a gentleman! Try to be nice to the other MSers... we’ll get further down the road this way... I did the best I could with what I have... Based on size and energy requirements... this tiny device isn’t going to do very much... Now, I have forgotten... what was the OP’s hope for statement? If blowing cold air at one person is what he is interested in... bingo! It will do that. Not very much, nor very cold... A Mooney cabin is about the scale of a car... look up the parts for an automotive AC unit... Or look at the back of a home refrigerator.... What is surprising... is how well a cooler full of ice can chill a Mooney for a couple of hours... ice machines have a pretty big compressor and heat exchanger attached to them... For additional comparisons... find the smallest AC unit for a dorm room... compare the tech specs of that... The challenge for planes is the amount of heat coming in... on a sunny day, a hot day, with four people on board, traveling at 150kias... or parked on the black-top loading up, or doing a run up... or having a long taxi... All things that are going to try to heat the cabin... Best regards, -a- Quote Link to comment Share on other sites More sharing options...
jaylw314 Posted April 29, 2021 Report Share Posted April 29, 2021 (edited) On 4/28/2021 at 7:29 AM, A64Pilot said: Well here is the site the OP linked to https://www.zerobreeze.com/pages/mark2-specs ‘I don’t see where it says BTU, and I never said it was a Peltier plate, I said many are, and those that are are essentially worthless. ‘However 2300 BTU isn’t bad at all, smallest window unit AC I’ve seen was 5,000 for example. ‘I’ve got quite a bit of experience through others with these “miracle” battery powered airconditioners with people with sailboats, everybody wants something that can get them through a hot night, or at least cool the cabin down enough to get to sleep, and unfortunately it just doesn’t exist, Airconditioning on a boat requires a generator at some time. Average smallest window unit AC (5,000 BTU) pulls after start up about 6 amps at 120 VAC, that’s about 720 Watts and that’s just under 1 HP, and that’s a LOT of power. Sure it can be decreased some by using expensive components, but not by much. ‘It’s also 60 amps at 12V, which is of course is everything a lot of our alternators are capable of producing, for a battery to supply 60 amps and not be real heavy and or real expensive for any amount of time would be real impressive. But this unit is 2300 BTU, so “only” half that, but 2300 BTU still takes serious power, 30 amps at 12V, which isn’t trivial at all, maybe 25 or so is realistic ‘Of all the small compressors available the Danfoss type has been the best for a very long time both from a service and from an efficiency standpoint, they get there by being brushless DC, which means among other things that they can be variable speed. All of the new house type AC’s, refrigerators etc that advertise they are ”inverter”units are actually brushless DC, because that’s how brushless DC motors work, and they can be more efficient, just not a whole lot. https://www.danfoss.com/en-us/products/dcs/compressors/compressors-for-refrigeration/direct-current-compressors/#tab-overview Recently Sawafugi developed a neat new tiny compressor, they call it a swing motor, it’s fascinating in its simplisticty, it’s just a piston and a spring that’s actuated by an electromagnet for the compression stroke, and the springs do the intake, then select springs who’s natural frequency corresponds to the RPM of the compressor and your compressing a gas without an electric motor and crankshaft etc. Real neat, but unfortunately it’s not more efficient than the Danfoss. But lots less moving parts and may last a very long time, bu sealed compressors like the Danfoss often run for 90,000 hours or more, so that’s tough to beat. https://www.sawafuji.co.jp/en/technology/swing_motor/ The bottom line is that unless or until there there is a large breakthrough in efficiency like LED’s were for instance in lighting, that effective airconditioning in small lightweight units, especially battery powered ones just isn’t possible. Still I’m impressed with 2300 BTU out of a 17 lb unit, but have to wonder about battery weight and expense as well as run time, because 2300 BTU takes quite a bit of power. Portable small airconditioners, especially battery powered ones are very similar to an electric airplane. It’s possible I guess, just not with current technology Can AC's even get much more efficient than they are now? I mean, with the compressive cycle I assume there's a crummy theoretical maximum like the Otto engine, right? I suspect that was part of the appeal of peltier coolers, that they wouldn't be theoretically bound by the thermodynamic limits of compressive cooling. Of course, in real life, they just end up even crummier. BTW, what does "1 ton" refer to for AC's? I assume the D model Apache does not lug around a 15,000 lbs unit? Edited April 29, 2021 by jaylw314 Quote Link to comment Share on other sites More sharing options...
EricJ Posted April 29, 2021 Report Share Posted April 29, 2021 48 minutes ago, jaylw314 said: Can AC's even get much more efficient than they are now? I mean, with the compressive cycle I assume there's a crummy theoretical maximum like the Otto engine, right? I suspect that was part of the appeal of peltier coolers, that they wouldn't be theoretically bound by the thermodynamic limits of compressive cooling. Of course, in real life, they just end up even crummier. BTW, what does "1 ton" refer to for AC's? I assume the D model Apache does not lug around a 15,000 lbs unit? Most things that can be characterized by thermodynamic cycles are known to not be very efficient. It's the nature of the beast. Without a heat sink that is at absolute zero, it is difficult to attain anything close to thermodynamic efficiency, so it's all just relative. That said, technology for air conditioners keeps changing with new tricks and things. There are some guys at my house right now putting in a fancy new "variable capacity" system to replace the "two stage" system that was the bee's knees a little over a decade ago. Apparently this thing also manages some optimizations of switching or even mixing between the heat pump or gas furnace use in the winter. We'll see. Peltier coolers are known to be less efficient than vapor phase systems, but they solve some problems that are important in some applications. e.g., they have no moving parts other than whatever fans might be needed and they can be made small to spot cool things (like the beverage coolers in high-end cars, etc.). For some applications the relative lack of efficiency is not as important as just being able to have the cooling function. AC "tons" are apparently a throwback to when block ice was used to cool in the summer. Apparently the tonnage is intended to reflect the equivalent amount of ice that would be needed to do the same job. There is a BTU equivalent, but in this country it is tradition to always use the most confusing measurement units possible, so we get "tons". 1 Quote Link to comment Share on other sites More sharing options...
aviatoreb Posted April 29, 2021 Report Share Posted April 29, 2021 Fun facts about the history of the ice industry: Old school AC. The North Country used to ship ice all around the world - as far as India in big ice ships. So that the well heeled could enjoy ice cream on a summers day in Bombay in 1872. Apparently the cutting of ice out of winter lakes for storage and use through the year lived on to some degree even until the 1950s. Quote Link to comment Share on other sites More sharing options...
A64Pilot Posted April 29, 2021 Report Share Posted April 29, 2021 1 Ton of airconditioning is 12,000 BTU, I have no idea where that number came from, could be a ton of ice I guess. So the D model with its 7.25 ton AC’s had 87,000 BTU per side, it could operate on one, but they were actually very reliable, I never had one break. ‘Average house has about 2 1/2 tons of airconditioning or said another way 2 1/2 tons is good for a little over 2,000 sq ft, depending on where you live and how well the house is insulated and it’s thermal mass. There are “tricks” to increase efficiency, for example a fixed orifice used to be the standard for causing the big pressure drop to get the liquid to evaporate into a gas and absorb heat, then a variable orifice called a thermal expansion valve was used and based on temp could control the size of the opening and more closely match the demand, now it’s a digital sensor that runs a stepper motor that controls that orifice, and on heat pumps there are now two of them. So same thing, just now digitally controlled and more precisely metered. ‘Also what helps a lot is to increase the size of the condenser, the bigger you make it, the more heat it can give up and that increases efficiency. Remember not too many years ago a house AC was just a small box with the condenser on one side, now they are tall towers with the condenser wrapped all the way around the tower. That greatly hurts small, especially portable AC’s because you have to keep them small and can’t have a big condenser. ‘The latest greatest thing is “inverter” compressors, they are actually just DC brushless motors, but they can be run at variable speeds. slow one down in effect makes it smaller and then you have effectively increased the condenser and evaporator size, so the efficiency increases by quite a bit, plus you can keep cycle time at optimum by varying compressor speed based on heat load, so it can idle all night long, but in the heat of the day it can actually go into overdrive if needed on an unusually hot day. The aren’t gimmicks, they work and its old proven technology, my next house heat pump will be a inverter system. So just like car engines for instance where you can increase efficiency by digital controls by quite a bit, your still limited by the inherent limits of what an otto cycle engine can deliver, same with airconditioning, until or unless something game changing like LED’s were for lighting , small portable battery powered effective airconditioning just isn’t possible 1 Quote Link to comment Share on other sites More sharing options...
A64Pilot Posted April 29, 2021 Report Share Posted April 29, 2021 (edited) Peltier coolers are great for small things that need some spot cooling, only moving part is a fan, and you don’t need cold, just cool Vapor Cycle is still the most efficient, that’s what our regular AC’s are, the major cooling comes from the change from a liquid to a vapor, then the compressor compresses it back into a high pressure but makes it hot doing so, so a condenser is used to cool the compressed gas down to a liquid again, then evaporate it into a gas and repeat. There are also airconditioners that work off of just compressed air, a charge air cooler, air gets cold as it expands, anybody who has drained a air compressor has seen that. ‘The A model Apaches air conditioner worked that way, and down in Southern Alabama it would spit ice at you as it used the water that condensed to help the cooling, but it was overwhelmed in the desert heat where there was no humidity, it was less efficient, but much lighter than a vapor cycle system. 400F air came in one end, and just below freezing air came out of the other end. ‘I think but am not certain that Commercial jets “air pacs” work off of bleed air and there is no compressor or refrigerant. Edited April 29, 2021 by A64Pilot 1 Quote Link to comment Share on other sites More sharing options...
EricJ Posted April 29, 2021 Report Share Posted April 29, 2021 1 hour ago, A64Pilot said: There are also airconditioners that work off of just compressed air, a charge air cooler, air gets cold as it expands, anybody who has drained a air compressor has seen that. ‘The A model Apaches air conditioner worked that way, and down in Southern Alabama it would spit ice at you as it used the water that condensed to help the cooling, but it was overwhelmed in the desert heat where there was no humidity, it was less efficient, but much lighter than a vapor cycle system. 400F air came in one end, and just below freezing air came out of the other end. ‘I think but am not certain that Commercial jets “air pacs” work off of bleed air and there is no compressor or refrigerant. AKA, Air Cycle Machine. That's the same thing as the "pac" in airliners. They run off the compressed air from the engine compressor bleed. Air Cycle Machines were invented in the 1800s right after steam engines provided a way to distribute power via compressed air. Steam ships crossing the oceans could refrigerate cargo, e.g., food, meat, etc., and passengers. The same basic design has been used in turbine/jet aircraft for many decades. In many/most turbine aircraft the bleed air simultaneously provides cabin pressurization and air conditioning. Both are needed simultaneously since the bleed air is quite hot coming out of the engine compressor. They're nifty machines, but the turbines inside the ACM can 'splode, and if there is a bearing anywhere (engine, ACM) bleeding oil it'll stink up the cabin. My understanding is that the most modern airliners, e.g., 787, no longer use bleed air for accessories and cabin pressurization and a/c are all electrically driven (i.e., vapor cycle air conditioners). Quote Link to comment Share on other sites More sharing options...
jaylw314 Posted April 30, 2021 Report Share Posted April 30, 2021 22 hours ago, EricJ said: Most things that can be characterized by thermodynamic cycles are known to not be very efficient. It's the nature of the beast. Without a heat sink that is at absolute zero, it is difficult to attain anything close to thermodynamic efficiency, so it's all just relative. That said, technology for air conditioners keeps changing with new tricks and things. There are some guys at my house right now putting in a fancy new "variable capacity" system to replace the "two stage" system that was the bee's knees a little over a decade ago. Apparently this thing also manages some optimizations of switching or even mixing between the heat pump or gas furnace use in the winter. We'll see. Peltier coolers are known to be less efficient than vapor phase systems, but they solve some problems that are important in some applications. e.g., they have no moving parts other than whatever fans might be needed and they can be made small to spot cool things (like the beverage coolers in high-end cars, etc.). For some applications the relative lack of efficiency is not as important as just being able to have the cooling function. AC "tons" are apparently a throwback to when block ice was used to cool in the summer. Apparently the tonnage is intended to reflect the equivalent amount of ice that would be needed to do the same job. There is a BTU equivalent, but in this country it is tradition to always use the most confusing measurement units possible, so we get "tons". Ah, thanks, I did a double-take when I first saw "tons" I've always wondered why we don't use the household water supply as a cooler for AC condensers--preheat the water going into your water heater, since you still need hot water during the summer Quote Link to comment Share on other sites More sharing options...
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