Thank you. I was sure considering this, since I live in Houston and my electric bill was ENORMOUS in June. But, I am glad that you did a realistic test. So, I will not do this now. I wrote this comment a 2nd time to make sure you saw it. Thanks again for running this test. That really helps me SCIENTIFICALLY evaluate this.
Enjoy your videos! Helps keep fresh with things now being a service manager for roughy 5 years now. Purposely try to make regular visits on basic technician field work to stay humble lol
Here in Texas, it's been over 100 for the last 3 weeks. Low humidity for the most part. I am looking to save wear and tear on equipment by using misters. I just started recently so I have no data. While I agree that engineers look at things when designing stuff, they don't make them as good as they should otherwise they would be very expensive. Anyway, I did enjoy the testing and the break down.
I agree. I see no savings,no advantage to this product. Actually just the opposite,as for cost. This video kind of reminds me of others you've published. Like High Efficiency vs Cost ?? Great work as always G-Man.. Always an inspiration of thought and knowledge...
Modern window units do splash water (from the evaporator) onto the condenser, rather than simply draining it. Based on the semi-circle of corrosion on the condenser of mine, I'd say it definitely reduces the lifespan of the unit, and the manufacturer is probably a-ok with selling more units as a result.
Years ago I did a similar experiment by building, in essence, a swamp cooler around the outside of the coil. That was before I had any instruments to test the results, and had family members that didn't appreciate my experiments. The only thing I know is that the air coming out of the condenser fan was about the same temperature as the ambient air. But one thing about that system is you don't have the problems of minerals getting into the coil.
Interesting video. I have to agree with you about the concern on the mineral content of the water messing up the coils. That could be taken care of by having a tank, bucket or large a jug of distilled water and an RV-style on demand water pump. A home air conditioner's function it to mechanically and, using the physical properties of the coolant, move heat from the interior of the home to the exterior. It functions as a one-way heat pump. While your 6.9% drop in energy usage is valid, it's not the whole story. It woud work better to also time the function of the air conditioning condensor unit with the spray off, then the spray on, for about three or more cycles, at different times of the day, to see how the sprays affect the overall energy usage, not just what the wattage consumption is. You want to look at kilowatt-hour differences (or, more easily, watt-minutes) rather than just the difference in the wattage used. A shorter cycle would indicate that the heat transfer from inside the home to outside the home is more efficent with the spray going. Just for the sake of example, let's say that the cycle is 15 percent shorter, averaged through different times of day (noon, 5 pm and 10 pm as examples). The efficiency gain for using the spray would then be (difference in wattage) x (difference in time). In this instance, you're using 93% of the energy (watts) and for 85% of the time; so the usage would be 79% of what it is without the spray, or a 21% gain in efficiency. By alternating the cycles, you get a realistic look at what's happening at a particular time of the day. Of course, as you mentioned, you did the test at 30% humidity. The gain in efficiency would likely be higher where the air is drier (desert) and lower where it's very humid (Gulf coast, for instance). The more efficient you can make the heat transfer, the better; that's why a geotheral setup (burying the coils underground) is so efficient, because the transfer happens at a relatively steady temperature with a medium that can absorb the heat well (not geothermal as in geysers, but geothermal as far as either a trench dug in a back yard, or a well dug down about 30 feet, with the coils there, rather than in the traditional condensor). A river would be another alternative, other than the environmental problems of heating a river and possible fish kills. The cooling towers of nuclear power plants are an example of how a pool of water can be used for cooling.
Taking your comments one at a time, distilled water is quite corrosive. Not good for the dis similar metals of the coil. I have done numerous trials with these misters. This is as good as it gets. Averaging is almost impossible to make work. Too many variables. GFM
@@grayfurnaceman fyi: I found four videos. If there's a fifth, it's not showing up in your search results. Regardless, video #1 showed the following data: - 90F ambient temperature. - 30-31% relative humidity - 87-88F air temperature after turning on the misters. The psychometric chart indicates that at 90F and 30%rh, the dew point is approximately 55F. Call it 60F to account for error. if we've properly implemented evaporative cooling, air entering the condenser should be about 60F. You measured 87-88F entering the condenser - a drop of at most 3F. That means you realized (90-87)/(90-60) = 3/30 = 1/10 = 10% of the available evaporative cooling. I.e. the problem is not with misting, per se. The problem is that this particular implementation of misting was inefficient. I can think of two ways to follow up on this experiment: 1) Buy an actual misting system and see if it works better. If it does, there's an opportunity to explore how their design is different. 2) Define a grid of points all across the condenser surface. Take temperature measurements of air entering the condenser at all points, and average them. This will estimate the average temperature of air entering the condenser, and it will also tell us if the mister is evenly cooling the air.
Another advantage of misters is when a system is borderline on size. Most home builders will go with the cheapest price from a contractor. I see it all the time, 2 ton a/c with 1400 square feet, high ceilings etc. On 90-95 degree days the a/c struggles to keep up. The misters would help. The problem with just misting plain water is the sediment it leaves behind and would affect condenser coil life. R.O. water would be much better. The food chain I work for already has R.O. water on site.
That's my problem now. 2 ton with high ceilings. Don't want to dump the system yet. 90-95 deg days and mine runs all day. I'm just trying to find something to help cool everything off a little better. I can set mine at 73 and yesterday getting to 95, my house lost ground to 80 by 7pm.
Another method besides the misters would be sub cooling the liquid line. Solder 3/8" tubing along side 3/8" liquid line and run a pressure control to energize a humidifier solenoid or similar Lol ;) no corrosion on coil.
I definitely see the problem with coil scaling up. I'm certainly not a service guy but spent my entire career (petrochemical plants) around really, really big units. I see where you're coming from and saw you with the instruments hooked up. My question is concerning the delta P across the expansion device. My understanding is the greater the pressure drop, the greater the delta T. If that's the case, keeping the head pressure as high as possible but cooling the high pressure refrigerant by external means such as misting (water being a better source of heat transfer than air) would that lower refrigerant temperature equat to reduced temperature across the expansion device and reduced temperatures in the evaporater? I'm seeing the unit on my house and my son's apartment going into thermal overload every evening around 3:00 every day. Shut both units down and start back up around dark. They come up and cool for around 20 hours. Reason I'm pondering this is the service guy is bowed up till next week. Really appreciate the work you put into this. It's fascinating!
Great video! What was the approximate ambient temperature and humidity outside at the time of the test? I imagine that temp/humidity would make a large impact on the amount of evaporative cooling that you get from the misters? If it is 110F and 10%RH, then the evaporative cooling might be much more beneficial?
Misters would Help ALOT Right now in Palm springs , California. It Was 119 Degree's in the shade today in Palm Springs , 129 Degree's in the Sun Hitting a condenser , this is When u use Water misters to cool down Condensers. install with a temperature control & solenoid to only activate over 100 degree ambients.
throttle bottle here in Vegas... Along with other places that draw water from the Colorado River, for sure would damage the coils, unless you ran a line from your RO filtering system.
@No Akomplice So what was the cause? It sounds like you gained efficiency to the point of extracting enough humidity from the inside air to create a heavy drip at the evaporator. I bet using fewer jets to find a mid point where the condenser can keep up would work for your case.
I see these kits only provide one jet per side. Making your own system with more jets will would mean more mist and more heat transfer if the coils come in contact with more mist. I do agree that the savings is small. Maybe even a net loss if you figure in the cost of municipal water use or electricity if a well is in place. I'm just curious to know your thoughts on a better design with more misters (more and better placement) and a solenoid/relay (like mentioned below) to run only after a certain temp is reached.
I am wondering - from an efficiency viewpoint - that using the condensate water flowing from AC evaporator coil could be used to pre-cool the refrigerant line returning form furnace to compressor... being as this condensate is very cool in temp. My thoughts are having condensate water flow thru a PVC pipe that has the return AC line inside. To do this a slit would have to be cut in PVC pipe to enable placement of AC return line inside-condensate water flowing thru PVC pipe cooling the refrigerant line. A bit of plumbing to accomplish entrance/exit of condensate thru PVC could be done with some fittings/etc. Don't know how the condensate water would react with the copper return line or if algae buildup might be an issue but this might be a reasonable method to increase efficiency of AC cooling?
It could be effective in very high humidity areas. The question is how much? It would increase subcooling. I have not seen any damage to the copper lines in the refer units that use this method. For most A/C units it would require a pump as the condensate is located below most liquid lines. GFM
Appears the crux of this mister device is to lower outdoor air temperature, some small window units are indeed designed to splash condensate water on the the condenser, I am not completely convinced this is a good thing and here is why; under certain circumstances putting water on the fins of a condenser is almost like putting dirt on condenser fins ( high Humid conditions as an example ) , it affects the air flow which is not good. What I do for free is pre-cool the home in the morning ( to about 72 degrees) when the outside air temperature is near 70 degrees, this keeps the home cool ( dependent on outside air temperature) just about all day. ( even as outside temps go to 90+) In essence , using the home as a thermal battery. With an outdoor temperature near 70 or below in the morning, I can get about a 25+ degree delta compared to 18 to 20 degree delta at a higher outdoor air temperature. There by saving overall cost. Keep in mind there may be other factors involved such as expansion valves verses cap tubes, ect. Thanks for the video, good thinking fun for those of us that have a passion for HVAC.
Has anyone asked about the run time on the AC? My AC has ben running all day. I went and threw water on it and then 9 minutes later it stopped running.
The only time I would suggest using these as if the coil is completely shot and the head pressure is too high to operate. And of course it’s only being used as a temporary fix until the new condensing unit can be installed
Misters Would be very useful when the ambients hit 100+ degrees, Head pressure issues at High ambients. etc. odd days at 110-115 degrees like we have right now in california.
Air conditioners are designed to operate normally at these temps. They will not drop out on high pressure or temp. If the machine is not sized properly or is not charged correctly it may fail to deal with these temps. Changing the head pressure may, and as I have demonstrated, often does reduce operational efficiency. Just leave it alone. GFM
I've seen refrigeration self contained units use the drain water from the evaporator to cool the discharge line. System was designed this way. Same concept except no damage to condensing coil. I believe it's a tool to use when your system is under sized and in 100+ degree weather. These hvac units will totally stop working and over heat in the desert. Misters help to get through thr extreme days, ive seen it and used it. But if you're system is properly sized and in ideal weather I see no use. So my thoughts are rather than mist the coil how about pre cool the discharge line in a water source.
The condensate in those refrigeration systems is evaporated off to avoid having to provide condensate drainage to a drain. There is little condensate to provide better energy efficiency. Misters can be used with units that are (as you say) undersized, or not charged correctly. This is not an energy saving operation. It is just a way to get a system that is not capable of cooling a structure to get by. These devices are sold as energy saving devices. If a system is sized correctly (including the ductwork) and operating at its best efficiency, it should operate normally at well over 100F. GFM
grayfurnaceman I agree. I assumed it was a dual purpose. I was in Coachella this past week and many units not wanting to operate in the 127° weather. Seen a few guys use a water source to cool compressor and head pressure. I'm new to thr field. Taken several classes and this is my first summer. Doing 80 hour weeks, it's kicking my butt. Appreciate your videos and the knowledge you share. Ive honestly benefited from watching your videos.
Thanks for the support. I don't think any unit is up to 127F. That is pretty much beyond the limits. Cheer up, it will end and the bank account will love you. GFM
Great video as always. I do have a question though- How could helping the unit cool its refrigerant cause a reduction in performance? Not saying that you are wrong, it just makes no sense to me. Thanks.
The compressor didn't have to work as hard, and didn't, as indicated in the first video. I'll give you my theory on the delta T. Since it(compressor) is a pump and was not working as hard maybe the pressures were slightly different at the metering device and it didn't make a perfect adjustment. If the engineers were to design systems around the misters they would more than likely get better results. The downside of the coil deposits and the water usage is too much to be worthwhile. If it used just 4 gallons a day, that may not seem like much, but you multiply that times every condenser in the world and you have wrecked havoc on the freshwater supply of our planet.
I think that you would be better off rigging those misters at about 7.5-8 feet off of the ground to a gazebo, awning or the patio perimeter and creating an outdoor a/c like you find at an outdoor patio restaurant in AZ. Frankly, that is the only way that I see enjoying any "real" additional comfort from that device.
Say your amp draw comes down 2 amps from 13 on a 3 ton unit or 480 watts, round numbers .5 Kwh, which is conceivable on a very hot day. Average price 12 cents a Kwh, you save 6 cents an hour when running and destroying your unit. How about insulating your attic instead. When you run the correct numbers, it always tells the story.
Just imagine here in South Florida, that water misting system, with the salt y weather, would corrode the outside coil in less than a year. Plus the calcium build up in the coils, that you mentioned would be very costly to clean up, with acid.
"if it worked they would already be doing it" Isn't of itself proof something doesn't work. You demonstrated that your setup wasn't worth the hassle fro you. I personally don't care if it works or not, I just think a better attitude to experimenting is to be less confrontational and more collaborative. My dad suggested using misters 15 years ago, i thought it was a stupid idea then I think its a stupid Idea now. The simple fact is there isn't much time that the air is in contact with the fins. i do think there are things that we can do that can make the average AC unit more effective. I do think some of them are worth the hassle, but I also think there are other things that are more important then trying to fix something that isn't broken. If I had more time sure, but right now my AC works fine. I would rather spend the time decreasing my AC need by 30 % then getting 10% more efficiency out of my system.
There is one situation that something like this works, I use it myself for this reason. In fairly dry, 100+ F days. I live in an area that gets pretty extreme weather like this for a couple months, and even 2 year old unit just can't keep up. Come 1-2pm the temp indoors will just rise until about 6-7pm when it's above 100. About a 7-10 degree rise on hot days. So your 74 degree house is now 80-84 degrees. Then it starts dropping until it gets back down to 74 again around 12pm. On those days, if I run a drip hose on top of the coils, I can keep that temp rise from 0-3 degrees. Run a slow drip for a couple hours. It seems that the water pulls just enough heat away to compensate for the units inability to pull enough heat out with the hot air. This has been a life saver the last couple of weeks here in TX where we've been seeing 106-111 days recently. Just for reference - the house has 20 inches of insulation in the attic and radiant barrier. It does have few fairly new windows on the west side. And those have helped, but still, since the AC unit runs for almost 8-9 months a year, over sizing the unit would probably be inefficient outside of July and August. I do clean the coils with CLR and/or vinegar every other week, and give it a good hose down to avoid any build up. And hit it with actual coil cleaner once a year.
Honestly, I haven't checked. I only started doing this during that big heat wave the last few weeks. And, it's too hot to really work out there on the unit for any length of time for me. Once it's below 101 it keeps up pretty well, the house is warmer on the west side in the afternoon, but as long as the doors are open it stays comfortable. The water is not completely wasted, we have to water our foundations here to prevent dry shrinking/wet swelling of the ground under and around the house to prevent the foundation cracking. So, the drip lines are doing double duty any way. I base the usefulness off the fact that I can get a drop in temp of the air exiting the vents. Basically the decrease is about 5-7 degrees below ambient in the house, vs 1-3 below ambient. The unit may be a tad undersized based on the impact of the afternoon sun on the house. I used to have two trees that blocked about 50% of the sun in the afternoon, but both were damaged in a ice storm about 4 (maybe 5) years back. Split off right down the trunk. The previous owners had planted Bradford Pears and not properly pruned them, and they were a mess. Those trees are known for being easily split.
The house is 1800 with a 3 1/2 ton basic unit, nothing fancy. The unit is in the shade except from about 11 to 1 each day. I basically rigged this drip system up and put it on a cheap temp sensor switch, like people use for brewing beer in deep freezers. It turns on when it hits 102, and opens a valve. There is a possibility that better insulation on the plenum might help, it's pretty crappy, but that's a task for the winter. Currently it has old 3/4" glass insulation fiber board around it, and it's not that great. We've had a couple "mild" summers the last two years (just a few days above 101), so I got lazy/forgetful about increasing the insulation to a more acceptable level. That complacency may be what's biting me in the butt this year. The last couple of weeks have been remarkable, so I in no way mean to imply this is good or general solution. Just a quick "fix" to solve a very immediate problem. Sort of like my sister with her two 23 year old r-22 units on her house. They keep over heating and need complete replacement, they've been running a slow sprinkler on the system to keep it from over heating until they can afford to have the units replaced. They bought the house in the winter, and trusted the sellers inspection, first spring, they regretted that.
yea, a 1800 sq. ft house with 3.5 tons on it is not enough unit when temps get above 100 degree's. especially if its got over 10 years of compressor run time on it. i have used a figure of 400 sq. ft / ton for many years now and it kicks ass and saves people alot of money in electricity costs. Put a 5 ton unit on your house , upsize the return air intake to accomodate and You will be Sitting comfortably ina 72 degree house at all times no matter the ambient.
Misters will work.... but only if you mix.... it with dry ice and air and water combined.... and modulate solenoid valve to produce enough flow based on super heat values. Also misters are a good solution for situation where homeowner made a mistake and bought a unit that is wrong size... and can’t back out of it... due to unit being too expensive to replace... In which case misters integrated with automated based regulated solenoids will work... and will reduce energy bill and overall amps usage... Plus in cases where homeowner wants ac to simply be able to cool better on hotter days... and get to 72 degrees.... then adding a mister will help... Especially if it has multiple misters.... to compensate for couple of hours... during bad hot weather day.... This is not about simply saving energy.... it’s about homeowners staying comfortable due to mistake they made.... Hence if it doesn’t save any money I’d still do it as long as I can bring down temp on a 95 degree day to 72 degrees... and totally ok with spending some money on calcium filter and small increase in water bill... all that so I can have cool air.... and not die from heat. Dry ice in a thermal container and some air combined spitting out of 2 parallel based nozzle one with water that is mixed with dry ice and the other with air.... will reduce ambient temperature significantly lower around ac... This mister solution also useful for folks who installed their ac under deck or stairs... but didn’t leave enough clearance on top. Dry ice is cheap and can stay cool for a long time in a thermal container sort of like refrigerator.... has ice in it. When water flows into container mixed with dry ice... it will get colder... With one block of dry ice this can help folks survive for a good portion of a day. Also adding solar panel with inverter to use some additional energy helps as well.. Also adding foam spray around the attic helps as well and insulation of windows... in combination having similar mister system spraying roof on a hot day... Will it save more energy? With dry ice and air and water mixed together ? Sure... Is it the main intent for a homeowner? To save energy? The answer is no... the main intent is to stay comfortable... Get a heat thermal monitor and add several layers of mist mixed with dry ice air and water and see how much temp drops... Set it up that the mist works only based on super heat values... meaning you’d need sensors to be setup for temp probes etc. Where solenoid valve automatically release more water flow depending on.. super heat values.... Simultaneously have the roof sprayed as well... you can use water from rain store the wafer from rain in a container and reuse it on days when it’s hot to spray the roof... do so automatically or interconnect to Alexa and by voice. In regards to coils being corroded.... if that’s the case... then anytime it rains ac would get corroded... acs are designed to handle rain... Sure city water can have calcium agreed.... but add a filter even if it’s double filter... it’s ok... as long as the temp levels can be brought down to stay comfortable....For the homeowner.... Alternatively homeowner can just get another unit... but sometimes attic space won’t allow for that or budget reasons won’t allow for that.... and hence that is when misters make sense.... But they only make sense when existing system is not powerful enough and has high head pressure.... and when energy is not the only goal.... My name is Rome and I am an engineer and not HVAC but cyber security one... with masters degree in mathematics and enthusiasm for HVAC field. You right engineers think differently... vs HVAC folks.. yet we all somehow want the same thing... comfort of a system... and perhaps a bit of saving on energy costs... Also I am ok with spending a bit of money on dry ice... totally worth it.... if it means the difference between me stay hot or not... Besides think about it... misters don’t need to operate all the time... only on the hot days... when system can’t handle the load... But I did love your tests with the meter and it was truly cool to see... Your videos are very educational and help us the regular homeowner folks do HVAC work ourselves as much as possible without spending too much money on contractors. I like contractors and homeowners alike... no difference to me... what matters to me the most are the results... and results are clear to me... that the more you cool the outside temp the easier it will be... What’s also clear to me that similar thing can be done on air handler side where some ice can be introduced into air handler.... Simply by adding dry ice....to the air handler.... supply... Now is anyone doing it? I haven’t seen many folks do it... is it a good idea... yes providing it makes folks comfortable... however it would need to be done right in such a way that meets all the super heat levels (for fixed orifice systems).... Other option is to get rid of ac period and just go for ductless ac mini split... less electricity quiet motor and less hassle... Also adding hard 5 2 1 start capacitor with a relay can help in reducing the start up load and lights from flickering. Some homeowners don’t know this and end up spending tons of money on electricity... and never bother cleaning coils outside or inside and frankly speaking don’t even know how to change filters or the filters at.... that’s just the reality about the homeowners. Your videos helps folks stay educated and not get their brains degraded with all the tik tok videos. Good content absolutely love it.
So glad I watched this. To save one hundred dollars per year, while risking corrosion and more from the water is simply not worth it.
I've always wondered about this topic and I'm very glad you did these tests. I'm glad to know the outcome. thanks for your videos
Welcome
GFM
I agree with your conclusion. Doesn’t seem worth the hassle and the savings don’t seem justifiable. Love the videos as well!
Thank you. I was sure considering this, since I live in Houston and my electric bill was ENORMOUS in June. But, I am glad that you did a realistic test. So, I will not do this now. I wrote this comment a 2nd time to make sure you saw it. Thanks again for running this test. That really helps me SCIENTIFICALLY evaluate this.
Enjoy your videos! Helps keep fresh with things now being a service manager for roughy 5 years now. Purposely try to make regular visits on basic technician field work to stay humble lol
Great video, and I totally agree. Thanks for the video's.
Installed mister. No filter but once in awhile spray condenser unit with Dawn foam soap. Good cleaning agent. Keeps coils from mineral buildup.
Here in Texas, it's been over 100 for the last 3 weeks. Low humidity for the most part. I am looking to save wear and tear on equipment by using misters. I just started recently so I have no data. While I agree that engineers look at things when designing stuff, they don't make them as good as they should otherwise they would be very expensive. Anyway, I did enjoy the testing and the break down.
I agree. I see no savings,no advantage to this product. Actually just the opposite,as for cost. This video kind of reminds me of others you've published. Like High Efficiency vs Cost ?? Great work as always G-Man.. Always an inspiration of thought and knowledge...
Modern window units do splash water (from the evaporator) onto the condenser, rather than simply draining it. Based on the semi-circle of corrosion on the condenser of mine, I'd say it definitely reduces the lifespan of the unit, and the manufacturer is probably a-ok with selling more units as a result.
Years ago I did a similar experiment by building, in essence, a swamp cooler around the outside of the coil. That was before I had any instruments to test the results, and had family members that didn't appreciate my experiments. The only thing I know is that the air coming out of the condenser fan was about the same temperature as the ambient air. But one thing about that system is you don't have the problems of minerals getting into the coil.
Great video .......
Interesting video. I have to agree with you about the concern on the mineral content of the water messing up the coils. That could be taken care of by having a tank, bucket or large a jug of distilled water and an RV-style on demand water pump.
A home air conditioner's function it to mechanically and, using the physical properties of the coolant, move heat from the interior of the home to the exterior. It functions as a one-way heat pump. While your 6.9% drop in energy usage is valid, it's not the whole story. It woud work better to also time the function of the air conditioning condensor unit with the spray off, then the spray on, for about three or more cycles, at different times of the day, to see how the sprays affect the overall energy usage, not just what the wattage consumption is. You want to look at kilowatt-hour differences (or, more easily, watt-minutes) rather than just the difference in the wattage used. A shorter cycle would indicate that the heat transfer from inside the home to outside the home is more efficent with the spray going. Just for the sake of example, let's say that the cycle is 15 percent shorter, averaged through different times of day (noon, 5 pm and 10 pm as examples). The efficiency gain for using the spray would then be (difference in wattage) x (difference in time). In this instance, you're using 93% of the energy (watts) and for 85% of the time; so the usage would be 79% of what it is without the spray, or a 21% gain in efficiency. By alternating the cycles, you get a realistic look at what's happening at a particular time of the day. Of course, as you mentioned, you did the test at 30% humidity. The gain in efficiency would likely be higher where the air is drier (desert) and lower where it's very humid (Gulf coast, for instance). The more efficient you can make the heat transfer, the better; that's why a geotheral setup (burying the coils underground) is so efficient, because the transfer happens at a relatively steady temperature with a medium that can absorb the heat well (not geothermal as in geysers, but geothermal as far as either a trench dug in a back yard, or a well dug down about 30 feet, with the coils there, rather than in the traditional condensor). A river would be another alternative, other than the environmental problems of heating a river and possible fish kills. The cooling towers of nuclear power plants are an example of how a pool of water can be used for cooling.
Taking your comments one at a time, distilled water is quite corrosive. Not good for the dis similar metals of the coil. I have done numerous trials with these misters. This is as good as it gets. Averaging is almost impossible to make work. Too many variables.
GFM
@@grayfurnaceman What's the outdoor temperature and relative humidity (Or dew point; whatever you can measure) when you're running these experiments?
@@mthebold Start with the first part in the series. There are 5 and are linked at the end of each video.
GFM
@@grayfurnaceman fyi: I found four videos. If there's a fifth, it's not showing up in your search results.
Regardless, video #1 showed the following data:
- 90F ambient temperature.
- 30-31% relative humidity
- 87-88F air temperature after turning on the misters.
The psychometric chart indicates that at 90F and 30%rh, the dew point is approximately 55F. Call it 60F to account for error. if we've properly implemented evaporative cooling, air entering the condenser should be about 60F.
You measured 87-88F entering the condenser - a drop of at most 3F. That means you realized
(90-87)/(90-60) = 3/30 = 1/10 = 10%
of the available evaporative cooling. I.e. the problem is not with misting, per se. The problem is that this particular implementation of misting was inefficient.
I can think of two ways to follow up on this experiment:
1) Buy an actual misting system and see if it works better. If it does, there's an opportunity to explore how their design is different.
2) Define a grid of points all across the condenser surface. Take temperature measurements of air entering the condenser at all points, and average them. This will estimate the average temperature of air entering the condenser, and it will also tell us if the mister is evenly cooling the air.
30 year tech here. You rock.
I love your scientific mindset. Good data cuts through the BS every time.
Another advantage of misters is when a system is borderline on size.
Most home builders will go with the cheapest price from a contractor.
I see it all the time, 2 ton a/c with 1400 square feet, high ceilings etc. On 90-95 degree days the a/c struggles to keep up.
The misters would help.
The problem with just misting plain water is the sediment it leaves behind and would affect condenser coil life.
R.O. water would be much better.
The food chain I work for already has R.O. water on site.
RO water is also a problem as it is quite corrosive.
GFM
That's my problem now. 2 ton with high ceilings. Don't want to dump the system yet. 90-95 deg days and mine runs all day. I'm just trying to find something to help cool everything off a little better. I can set mine at 73 and yesterday getting to 95, my house lost ground to 80 by 7pm.
Good Job Sir good job thank you.....
When an a/c doesn’t run as long it will not remove the humidity as much OT at all. A/C is meant to run for a specific amount of time.
Another method besides the misters would be sub cooling the liquid line.
Solder 3/8" tubing along side 3/8" liquid line and run a pressure control to energize a humidifier solenoid or similar
Lol ;) no corrosion on coil.
As far as water on the THE CONDENSER here in Florida IT tends to get soaked by rain water and wind anyway
I definitely see the problem with coil scaling up. I'm certainly not a service guy but spent my entire career (petrochemical plants) around really, really big units. I see where you're coming from and saw you with the instruments hooked up. My question is concerning the delta P across the expansion device. My understanding is the greater the pressure drop, the greater the delta T. If that's the case, keeping the head pressure as high as possible but cooling the high pressure refrigerant by external means such as misting (water being a better source of heat transfer than air) would that lower refrigerant temperature equat to reduced temperature across the expansion device and reduced temperatures in the evaporater? I'm seeing the unit on my house and my son's apartment going into thermal overload every evening around 3:00 every day. Shut both units down and start back up around dark. They come up and cool for around 20 hours. Reason I'm pondering this is the service guy is bowed up till next week. Really appreciate the work you put into this. It's fascinating!
Amen my friend
Great video! What was the approximate ambient temperature and humidity outside at the time of the test? I imagine that temp/humidity would make a large impact on the amount of evaporative cooling that you get from the misters? If it is 110F and 10%RH, then the evaporative cooling might be much more beneficial?
There is an earlier video with all the specs listed. Check here: ua-cam.com/video/GEHE69OC9Xk/v-deo.html
GFM
Misters would Help ALOT Right now in Palm springs , California. It Was 119 Degree's in the shade today in Palm Springs , 129 Degree's in the Sun Hitting a condenser , this is When u use Water misters to cool down Condensers. install with a temperature control & solenoid to only activate over 100 degree ambients.
Arizona would be a great place, as well as other low humidity desert areas. that is if they have enough water to run it..
throttle bottle here in Vegas... Along with other places that draw water from the Colorado River, for sure would damage the coils, unless you ran a line from your RO filtering system.
@ james koenig --- or u could use a good quality water filter with a scale inhibitor in it. such as a Everpure insurice 4000 water filter cartridge.
No Akomplice so what was the issue?
@No Akomplice So what was the cause? It sounds like you gained efficiency to the point of extracting enough humidity from the inside air to create a heavy drip at the evaporator. I bet using fewer jets to find a mid point where the condenser can keep up would work for your case.
What was the outdoor air temperature?
Seems to me, misters or pre- coolers.
I see these kits only provide one jet per side. Making your own system with more jets will would mean more mist and more heat transfer if the coils come in contact with more mist. I do agree that the savings is small. Maybe even a net loss if you figure in the cost of municipal water use or electricity if a well is in place. I'm just curious to know your thoughts on a better design with more misters (more and better placement) and a solenoid/relay (like mentioned below) to run only after a certain temp is reached.
Have you watched the entire series?
GFM
@@thomasshelbyUS In my opinion, misting of A/C units to reduce head pressure is not an effective method of reducing energy usage.
GFM
Water is destructive to these units. Yes it lowers amps but the cost of repair from water destruction will be very high.
Agreed
GFM
I am wondering - from an efficiency viewpoint - that using the condensate water flowing from AC evaporator coil could be used to pre-cool the refrigerant line returning form furnace to compressor... being as this condensate is very cool in temp. My thoughts are having condensate water flow thru a PVC pipe that has the return AC line inside. To do this a slit would have to be cut in PVC pipe to enable placement of AC return line inside-condensate water flowing thru PVC pipe cooling the refrigerant line. A bit of plumbing to accomplish entrance/exit of condensate thru PVC could be done with some fittings/etc. Don't know how the condensate water would react with the copper return line or if algae buildup might be an issue but this might be a reasonable method to increase efficiency of AC cooling?
It could be effective in very high humidity areas. The question is how much? It would increase subcooling. I have not seen any damage to the copper lines in the refer units that use this method. For most A/C units it would require a pump as the condensate is located below most liquid lines.
GFM
Agreed
Appears the crux of this mister device is to lower outdoor air temperature, some small window units are indeed designed to splash condensate water on the the condenser, I am not completely convinced this is a good thing and here is why; under certain circumstances putting water on the fins of a condenser is almost like putting dirt on condenser fins ( high Humid conditions as an example ) , it affects the air flow which is not good.
What I do for free is pre-cool the home in the morning ( to about 72 degrees) when the outside air temperature is near 70 degrees, this keeps the home cool ( dependent on outside air temperature) just about all day. ( even as outside temps go to 90+) In essence , using the home as a thermal battery. With an outdoor temperature near 70 or below in the morning, I can get about a 25+ degree delta compared to 18 to 20 degree delta at a higher outdoor air temperature. There by saving overall cost. Keep in mind there may be other factors involved such as expansion valves verses cap tubes, ect. Thanks for the video, good thinking fun for those of us that have a passion for HVAC.
Has anyone asked about the run time on the AC? My AC has ben running all day. I went and threw water on it and then 9 minutes later it stopped running.
The only time I would suggest using these as if the coil is completely shot and the head pressure is too high to operate. And of course it’s only being used as a temporary fix until the new condensing unit can be installed
Agreed
GFM
What about if you live in a very DRY area like Phoenix, Las Vegas or Mohave Desert?
I will be publishing a video in the near future that addresses low humidity.
GFM
Misters Would be very useful when the ambients hit 100+ degrees, Head pressure issues at High ambients. etc. odd days at 110-115 degrees like we have right now in california.
Air conditioners are designed to operate normally at these temps. They will not drop out on high pressure or temp. If the machine is not sized properly or is not charged correctly it may fail to deal with these temps. Changing the head pressure may, and as I have demonstrated, often does reduce operational efficiency. Just leave it alone.
GFM
A 6.9% difference would be huge in a place like the PHX area, but if it does something to the interior temperature, that might not be worth it.
I've seen refrigeration self contained units use the drain water from the evaporator to cool the discharge line. System was designed this way. Same concept except no damage to condensing coil. I believe it's a tool to use when your system is under sized and in 100+ degree weather. These hvac units will totally stop working and over heat in the desert. Misters help to get through thr extreme days, ive seen it and used it. But if you're system is properly sized and in ideal weather I see no use. So my thoughts are rather than mist the coil how about pre cool the discharge line in a water source.
The condensate in those refrigeration systems is evaporated off to avoid having to provide condensate drainage to a drain. There is little condensate to provide better energy efficiency. Misters can be used with units that are (as you say) undersized, or not charged correctly. This is not an energy saving operation. It is just a way to get a system that is not capable of cooling a structure to get by. These devices are sold as energy saving devices. If a system is sized correctly (including the ductwork) and operating at its best efficiency, it should operate normally at well over 100F.
GFM
grayfurnaceman I agree. I assumed it was a dual purpose. I was in Coachella this past week and many units not wanting to operate in the 127° weather. Seen a few guys use a water source to cool compressor and head pressure. I'm new to thr field. Taken several classes and this is my first summer. Doing 80 hour weeks, it's kicking my butt. Appreciate your videos and the knowledge you share. Ive honestly benefited from watching your videos.
Thanks for the support. I don't think any unit is up to 127F. That is pretty much beyond the limits. Cheer up, it will end and the bank account will love you.
GFM
Great video as always. I do have a question though- How could helping the unit cool its refrigerant cause a reduction in performance? Not saying that you are wrong, it just makes no sense to me. Thanks.
The compressor didn't have to work as hard, and didn't, as indicated in the first video. I'll give you my theory on the delta T. Since it(compressor) is a pump and was not working as hard maybe the pressures were slightly different at the metering device and it didn't make a perfect adjustment. If the engineers were to design systems around the misters they would more than likely get better results. The downside of the coil deposits and the water usage is too much to be worthwhile. If it used just 4 gallons a day, that may not seem like much, but you multiply that times every condenser in the world and you have wrecked havoc on the freshwater supply of our planet.
Thank you for explaining.
I think that you would be better off rigging those misters at about 7.5-8 feet off of the ground to a gazebo, awning or the patio perimeter and creating an outdoor a/c like you find at an outdoor patio restaurant in AZ. Frankly, that is the only way that I see enjoying any "real" additional comfort from that device.
Probably true.
GFM
Say your amp draw comes down 2 amps from 13 on a 3 ton unit or 480 watts, round numbers .5 Kwh, which is conceivable on a very hot day. Average price 12 cents a Kwh, you save 6 cents an hour when running and destroying your unit. How about insulating your attic instead. When you run the correct numbers, it always tells the story.
lol
hahahahaaaaa near zero Delta T change? Thats funny! Thanks so much for doing this! Well done! This is a useless hack and no-one should do this.
Just imagine here in South Florida, that water misting system, with the salt y weather, would corrode the outside coil in less than a year. Plus the calcium build up in the coils, that you mentioned would be very costly to clean up, with acid.
"if it worked they would already be doing it" Isn't of itself proof something doesn't work. You demonstrated that your setup wasn't worth the hassle fro you. I personally don't care if it works or not, I just think a better attitude to experimenting is to be less confrontational and more collaborative. My dad suggested using misters 15 years ago, i thought it was a stupid idea then I think its a stupid Idea now. The simple fact is there isn't much time that the air is in contact with the fins. i do think there are things that we can do that can make the average AC unit more effective. I do think some of them are worth the hassle, but I also think there are other things that are more important then trying to fix something that isn't broken. If I had more time sure, but right now my AC works fine. I would rather spend the time decreasing my AC need by 30 % then getting 10% more efficiency out of my system.
There is one situation that something like this works, I use it myself for this reason. In fairly dry, 100+ F days. I live in an area that gets pretty extreme weather like this for a couple months, and even 2 year old unit just can't keep up. Come 1-2pm the temp indoors will just rise until about 6-7pm when it's above 100. About a 7-10 degree rise on hot days. So your 74 degree house is now 80-84 degrees. Then it starts dropping until it gets back down to 74 again around 12pm. On those days, if I run a drip hose on top of the coils, I can keep that temp rise from 0-3 degrees. Run a slow drip for a couple hours. It seems that the water pulls just enough heat away to compensate for the units inability to pull enough heat out with the hot air. This has been a life saver the last couple of weeks here in TX where we've been seeing 106-111 days recently. Just for reference - the house has 20 inches of insulation in the attic and radiant barrier. It does have few fairly new windows on the west side. And those have helped, but still, since the AC unit runs for almost 8-9 months a year, over sizing the unit would probably be inefficient outside of July and August. I do clean the coils with CLR and/or vinegar every other week, and give it a good hose down to avoid any build up. And hit it with actual coil cleaner once a year.
What temp difference does your condensing unit run?
How many Sq. ft. is Your House ?
Honestly, I haven't checked. I only started doing this during that big heat wave the last few weeks. And, it's too hot to really work out there on the unit for any length of time for me.
Once it's below 101 it keeps up pretty well, the house is warmer on the west side in the afternoon, but as long as the doors are open it stays comfortable. The water is not completely wasted, we have to water our foundations here to prevent dry shrinking/wet swelling of the ground under and around the house to prevent the foundation cracking. So, the drip lines are doing double duty any way. I base the usefulness off the fact that I can get a drop in temp of the air exiting the vents. Basically the decrease is about 5-7 degrees below ambient in the house, vs 1-3 below ambient.
The unit may be a tad undersized based on the impact of the afternoon sun on the house. I used to have two trees that blocked about 50% of the sun in the afternoon, but both were damaged in a ice storm about 4 (maybe 5) years back. Split off right down the trunk. The previous owners had planted Bradford Pears and not properly pruned them, and they were a mess. Those trees are known for being easily split.
The house is 1800 with a 3 1/2 ton basic unit, nothing fancy. The unit is in the shade except from about 11 to 1 each day. I basically rigged this drip system up and put it on a cheap temp sensor switch, like people use for brewing beer in deep freezers. It turns on when it hits 102, and opens a valve. There is a possibility that better insulation on the plenum might help, it's pretty crappy, but that's a task for the winter. Currently it has old 3/4" glass insulation fiber board around it, and it's not that great. We've had a couple "mild" summers the last two years (just a few days above 101), so I got lazy/forgetful about increasing the insulation to a more acceptable level. That complacency may be what's biting me in the butt this year. The last couple of weeks have been remarkable, so I in no way mean to imply this is good or general solution. Just a quick "fix" to solve a very immediate problem.
Sort of like my sister with her two 23 year old r-22 units on her house. They keep over heating and need complete replacement, they've been running a slow sprinkler on the system to keep it from over heating until they can afford to have the units replaced. They bought the house in the winter, and trusted the sellers inspection, first spring, they regretted that.
yea, a 1800 sq. ft house with 3.5 tons on it is not enough unit when temps get above 100 degree's. especially if its got over 10 years of compressor run time on it. i have used a figure of 400 sq. ft / ton for many years now and it kicks ass and saves people alot of money in electricity costs. Put a 5 ton unit on your house , upsize the return air intake to accomodate and You will be Sitting comfortably ina 72 degree house at all times no matter the ambient.
THE MISTER SEEMS TO WORK ON THE HOT DAYS IN FLORIDA, BUT I WONDER IF SHADING THE CONDENSER FROM THE SUN WOULD HAVE THE SAME RESULTS
Try this video: ua-cam.com/video/014DggY8Mfk/v-deo.html
GFM
Misters will work.... but only if you mix.... it with dry ice and air and water combined.... and modulate solenoid valve to produce enough flow based on super heat values. Also misters are a good solution for situation where homeowner made a mistake and bought a unit that is wrong size... and can’t back out of it... due to unit being too expensive to replace...
In which case misters integrated with automated based regulated solenoids will work... and will reduce energy bill and overall amps usage...
Plus in cases where homeowner wants ac to simply be able to cool better on hotter days... and get to 72 degrees.... then adding a mister will help...
Especially if it has multiple misters.... to compensate for couple of hours... during bad hot weather day....
This is not about simply saving energy.... it’s about homeowners staying comfortable due to mistake they made....
Hence if it doesn’t save any money I’d still do it as long as I can bring down temp on a 95 degree day to 72 degrees... and totally ok with spending some money on calcium filter and small increase in water bill... all that so I can have cool air.... and not die from heat.
Dry ice in a thermal container and some air combined spitting out of 2 parallel based nozzle one with water that is mixed with dry ice and the other with air.... will reduce ambient temperature significantly lower around ac...
This mister solution also useful for folks who installed their ac under deck or stairs... but didn’t leave enough clearance on top.
Dry ice is cheap and can stay cool for a long time in a thermal container sort of like refrigerator.... has ice in it.
When water flows into container mixed with dry ice... it will get colder...
With one block of dry ice this can help folks survive for a good portion of a day.
Also adding solar panel with inverter to use some additional energy helps as well..
Also adding foam spray around the attic helps as well and insulation of windows... in combination having similar mister system spraying roof on a hot day...
Will it save more energy? With dry ice and air and water mixed together ? Sure...
Is it the main intent for a homeowner? To save energy? The answer is no... the main intent is to stay comfortable...
Get a heat thermal monitor and add several layers of mist mixed with dry ice air and water and see how much temp drops...
Set it up that the mist works only based on super heat values... meaning you’d need sensors to be setup for temp probes etc.
Where solenoid valve automatically release more water flow depending on.. super heat values....
Simultaneously have the roof sprayed as well... you can use water from rain store the wafer from rain in a container and reuse it on days when it’s hot to spray the roof... do so automatically or interconnect to Alexa and by voice.
In regards to coils being corroded.... if that’s the case... then anytime it rains ac would get corroded... acs are designed to handle rain...
Sure city water can have calcium agreed.... but add a filter even if it’s double filter... it’s ok... as long as the temp levels can be brought down to stay comfortable....For the homeowner....
Alternatively homeowner can just get another unit... but sometimes attic space won’t allow for that or budget reasons won’t allow for that.... and hence that is when misters make sense....
But they only make sense when existing system is not powerful enough and has high head pressure.... and when energy is not the only goal....
My name is Rome and I am an engineer and not HVAC but cyber security one... with masters degree in mathematics and enthusiasm for HVAC field.
You right engineers think differently... vs HVAC folks.. yet we all somehow want the same thing... comfort of a system... and perhaps a bit of saving on energy costs...
Also I am ok with spending a bit of money on dry ice... totally worth it.... if it means the difference between me stay hot or not...
Besides think about it... misters don’t need to operate all the time... only on the hot days... when system can’t handle the load...
But I did love your tests with the meter and it was truly cool to see... Your videos are very educational and help us the regular homeowner folks do HVAC work ourselves as much as possible without spending too much money on contractors. I like contractors and homeowners alike... no difference to me... what matters to me the most are the results... and results are clear to me... that the more you cool the outside temp the easier it will be...
What’s also clear to me that similar thing can be done on air handler side where some ice can be introduced into air handler.... Simply by adding dry ice....to the air handler.... supply...
Now is anyone doing it? I haven’t seen many folks do it... is it a good idea... yes providing it makes folks comfortable... however it would need to be done right in such a way that meets all the super heat levels (for fixed orifice systems)....
Other option is to get rid of ac period and just go for ductless ac mini split... less electricity quiet motor and less hassle...
Also adding hard 5 2 1 start capacitor with a relay can help in reducing the start up load and lights from flickering.
Some homeowners don’t know this and end up spending tons of money on electricity... and never bother cleaning coils outside or inside and frankly speaking don’t even know how to change filters or the filters at.... that’s just the reality about the homeowners.
Your videos helps folks stay educated and not get their brains degraded with all the tik tok videos. Good content absolutely love it.
so that's what you look like