Solar Powered Air Conditioner!

hi couple of months ago we posted a video on a revolutionary air conditioning system that does not depend on a compressor or freon gas but rather on a desiccant a concentrated solution of calcium chloride in water a couple of aquarium pumps some fans and some common PVC plumbing [Music] on a bench top model inside the lab we demonstrated an electrical efficiency that was a little more than twice as high as a typical window air conditioning system based on the fact that that was a pretty successful test and some of the comments by the viewers we decided to go the next step and actually upgrade the system with some modifications as well as substantially enlarged it so that we would have the possibility of actually cooling off a residential space today we're going to try to cool off the tech ingredients lab with this air conditioning system now if you're interested in the principles the physics some of the deep background you might want to take a look at that video because I go into a fair amount of detail during that video but today what I want to do is I just want to touch on what's going on here what's where the air is flowing or the desiccant where the water is flowing and give you an idea of one of what modifications we've made in the original system and then finally we're going to go inside and we're gonna see what kind of performance this has and if we can in fact cool off the room to begin with what's happening is that room air is being drawn through this lower duct through a centrifugal duct booster this is a DC brushless centrifugal fan that is typically used for say hydroponics or equalizing the flow and say a forced air heating system this forces air down into the bottom of what's called a Wye fitting W ye it's a common common common plumbing fitting and it's this Y shape at the bottom of this the setup this is 150 millimeter 6-inch diameter PVC tubing throughout as opposed to the 100 millimeter diameter tubing that we used in the previous video the air that's forced down here then travels up this straight column to the top where it's rerouted back into the room so there's a loop of air within this column simultaneously what's happening is there is a flow of concentrated cold 42 percent calcium chloride desiccant that is showering down this column in a counter current direction with the airflow the millions of small little water droplets or desiccant droplets provide a lot of surface area for interaction and because the desiccant has such an affinity for water it actually Yanks the humidity out of the air into the desiccant droplets that then accumulate down at the bottom here so that the air that's flowing back in here has been dehumidified as well as refrigerated we'll get into that now the fluid that's that hits the reservoir down here has to be refurbished because we've actually diluted it slightly and we have warmed it slightly by the process of transferring to the air and so that at walky pumped back there which is an aquarium pump pumps the liquid out of the reservoir to this solar water heater over here I'll get into the some of the details about that but basically this raises the temperature of the desiccant to between 40 and 60 degrees centigrade and because of that higher temperature the vapor pressure of water rises with temperature and so the desiccant has less affinity for that water for that water vapor at the higher temperature when that water then or that desiccant then flows back to the system from the heater it goes to the top of this column here and in the column is a common showerhead this is a $2.00 human being showerhead that sprays this water or this desiccant down the column in a counter current direction similar to what's happening here with another one of these duct boosters as the air is flowing upward so we then drive the humidity off of that desiccant and into the air outside what happens at the bottom here then is we have concentrated and somewhat still warm desiccant in the reservoir down here so what we need to do then is we need to drive off some of that residual heat and so the second iraqi pumped back there then pumps that warm concentrated desiccant into this heat exchanger which is just a fan mounted radiator that pulls outdoor air through it and drives off most of that residual heat and then the desiccant that comes out of here which is now cooler then travels up here to a second radiator this radiator is in the output of what's going on in here and what's going on in here is a transfer of heat that it's a evaporative column and so effectively what happens is cold humid air is passing through this radiator and pulling off some of the additional heat from that desiccant when the liquid leaves this radiator here it travels back down to the inner tube of a coaxial stainless-steel wort chiller this is we use this for brewing but these two stainless steel tubes which are coaxial with each other and then formed into a coil allow the desiccant to travel inside here and then eventually pass out this side here and then back up to the original tower to continue the loop what happened is with the reason that this thing is able to reduce the temperature is because this third column is a swamp cooler it's an evaporative cooler instead of desiccant at the bottom here we have plain water now you could use rainwater you could use gray water you could even use saltwater or sea water as long as you refurbish it occasionally as the concentration of the salt Rises bottom line is the airflow in the counter current here and the droplets of water here caused the water to evaporate and because water will absorb over 2,000 joules per gram of water evaporated the water that that survives the drop here falls into a reservoir and is substantially below outdoor temperature and the air that has flowed around those droplets is also cold that's what takes some of the additional heat out of the upper radiator and so when the water then flows to the bottom here it is pumped out by these small little pumps on the other side of this this tower and pass through the outer coil of the wort chiller and so this helps to reduce the temperature of the desiccant even even further with more heat transfer and then the water that comes out of this outer jacket of the wort chiller then travels back up to the showerhead in the top here so each one of the units are very similar in terms of their their panicle design but they're each serving a different function this is doing the actual refrigeration of the air and dehumidification of the air that's going into the room this tower regenerates the desiccant recon --scent rates it and this provides the evaporative cooling to cool the desiccant below ambient temperature so that what's what's transferring in the in this tower over here is not at room temperature not at outdoor temperature but substantially below it now one of the differences between this system and the one that we built on the bench a couple of months ago is obviously size this is 150 millimeter diameter tubing that's 100 millimeter diameter tubing in addition because we're lifting the fluid higher and because desiccant is very dense it's about 1.3 grams per cc we couldn't use the low powered 12-volt solar water heater pumps that we used in the original experiment we had to go to a slightly higher performance pump and that's why the Tewa walkies are back there just to lift it a greater distance in addition we discovered that it's not just surface area for interaction but it's surface area and volume of air flow and originally what we had done is we had packed these columns with what are called bio balls these are little nylon plastic balls they're made for marine aquaria to provide a large surface area for the interaction of air and water for bacterial or algae growth and by doing so we not only provided a lot of surface area but we also blocked some of the air flow making the fans less efficient so by going to the shower heads and using the millions of little droplets with their surface area we found that we actually got better performance because we got much better airflow in addition to having still a fair amount of surface area with the droplets it's also cheaper and easier because you don't have to fabricate a surface area material like we had suggested or using the bio balls the other component important part is that the humidified air that comes off the evaporative cooler in this case no longer is inside the room originally we were using this air as the refrigerated air inside the room at the expense of reintroducing some of the humidity that we pulled off in the first column in this case we're keeping all of the humidity outside were not reintroducing any and in addition if there is any kind of bacterial growth any Legionella growth anything that would be mmm something you don't want in the air this stays outside so we don't have any kind of cross-contamination the desiccant at 42% is bacteria sidle so not only does it filter dust and particles and acts as sort of a mechanical filter for debris but it also kills bacteria dust mites and other kinds of wee nasties that you don't want in your air so it serves several different functions and we don't have to worry about the buildup of any kind of contaminants the desiccant is never consumed unless something leaks or unless it gets particularly dirty and you don't have a filter in the system it should last theoretically forever so there's no real cost or consumable in the desiccant the only real consumable is the water that we're using to provide the the evaporative super cooling now the solar water heater that we're using here is an alternative to what we used on the bench top which was a small little Bunsen burner to provide heat to drive off the water from the desiccant but because of the fact that you don't need very high temperatures you can take advantage of waste heat sources you can use industrial waste heat one company in Germany that's building air conditioners like this uses the output from a typical compressor based air conditioner the hot air flow to actually heat the desiccant to drive off the humidity another really neat alternative is to use a solar water heater the advantage with this is it's extremely inexpensive this unit here cost us about forty five dollars to build and all it consists of is a loop of high-density polyethylene tubing is about 50 meters of it in here this is one and a half centimeter or half inch ID tubing forms a large coil in the bottom of this frame it's been painted over with some flat camouflaged black paint to absorb sunlight and then it's been capped with an e glass window and the process of absorbing the heat of letting the heat into the onto the surface here heats the inside air heats the tubing but because the e glass blocks thermal infrared that heat can't radiate back out and so it gets quite hot inside here and we don't waste the heat by radiating out through this glass what makes this so cost-effective is even though this is a 1.2 by 1.2 meter or 48 inch by 48 inch square it doesn't have to be those dimensions and in order to get the e glass inexpensively you can go to say a local glass supplier and get some offcuts from other projects that they may have and then design your box to fit what they have available nice thing about that is that we got this for about five bucks and the tubing cost about $35 and about a $5 can of spray paint and some lumber and we have a system that at the equator at noon would absorb about 1400 watts and because unlike a photovoltaic cell not only does this not contain cadmium but it costs less it's something you can do yourself and as a far higher efficiency the best photovoltaic panels out there will be around 22 maybe at best 22 percent conversion efficiency but because we're not heating the water very high or the desiccant very high we can get absorption up around 80 or 85 percent efficiency with this kind of a unit in addition if you mount this on say a roof it would block some of the heat of the Sun that would normally be heating your buildings so it kills several birds with one stone this design was presented on a channel called Desert Sun zero - we'll put a link to the channel below but they go through a fair amount of detail about exactly how to size this and how how to construct this and it's a nice video you might want to take a look at that at that channel in addition to the water heater system here obviously you have to invest in some plumbing you have to invest in some tubing but it's very flexible how you decide that you want to set everything up we just set it up like this for the demonstration but obviously if you're going to do a permanent installation you might want to do this a little bit differently now before I go in what I want to do is I want to show you what kind of power utilization we have here and then I also want to give you an idea of what the weather conditions are out here so we know what to compare to the inside one other thing that I should mention I do want to forget about that is that thermodynamically this system is less efficient than a regular air conditioner system thermodynamically but because the power the majority of the power that's being used to drive this is from a source that can be essentially free either waste heat or again solar heat we're not going to include that in the equation for efficiency because we're not paying for that once you set this up you don't have to pay anything so let's go over here and look at what kind of electrical use we have with this system before we go inside alright so down here we have a power meter and plugged into the power meter we have the distribution block here the three fans are plugged in back here we have the power supply for the two walky pumps back there and then we have the power supply here that provides 24 volts to drive the solar water heater pumps down there or the solar water pumps down there and the two fans on the radiator below the table so let's get an idea of what kind of power you're using so we can use that as a basis for comparison we'll go through the menu here so we're looking at about a hundred and sixty-five watts of power you can hear the water dripping in the background and before we go in I'm going to turn on this meter and we're going to take a look at what kind of temperature we have and what kind of humidity outside takes a little bit of time for this to stabilize but we're looking at about probably going to get to about fifty five percent relative humidity of 54 percent and about seventeen point three seventeen point four degrees now it's going to take a couple of minutes for all of this to equilibrate because the fair amount of water in the reservoir there takes a few minutes to cool down to optimal temperature and so we're gonna take a couple of minutes we'll get this set up inside and then we'll take a look and see what the air flows are and do some measurements alright so what we're going to do while we're waiting for the liquids inside the reservoir is to equilibrate to temperature based on the fact that it takes a little bit of time for the evaporative cooling and for the heat to circulate out of the solar heater what I'm going to do is get some of the numbers that we're going to be using for our future determination of the performance and I'm going to start with the diameter of the return duct up here as you can see it's about 175 millimeters across or 7 inches across and we can measure the velocity of the air that is traveling here [Music] out of the duct and it is closed to five meters per second so if we take to those two numbers and we look down at this little equation sheet I have here with a diameter of 175 millimeters if we do PI R squared we can determine that the area of the duct is 0.02 for square meters and because we're moving the air at five meters per second out of the duct we are moving 0.1 to 0-2 bikini ters per second air has a density of 1 point to 2 kilograms per cubic meter so therefore when you multiply these two we are moving 0.14 5 kilograms per second or 145 grams per second of air we're going to use that for future calculations [Music] you can see that we have an indoor temperature of about 67 degrees sixty four point four degrees we'll use relative measurements and I'll tell you why I'm using Imperial in a second but nevertheless I'm gonna hold this probe over here because this is the air coming from the room this is the general temperature of the air that we're trying to cool inside of the layout so sixty five point six degrees or so it's a little off of this but again calibration it's coming out of the duct we can see that it's substantially colder sixty five point six and we're already down to below 62 we're gonna give this a few more minutes to equilibrate but as you can see we definitely are cooling off room air keeping in mind that this is the amount of air that we're moving every second I'm going to look here at this other graph that will help us to understand a little bit about the other part of an air conditioning system which is the dehumidification process this is a graph that has multiple curves on it each colored curve represents a percentage of relative humidity relative humidity is the percentage of capacity of what of air for water vapor at any given temperature warmer air will hold more water so the relative humidity is temperature dependent at any particular relative humidity if we follow that particular line let's say for a certain temperature across here we can take the 10 percent relative humidity line and at 50 degrees move over to the y-axis and what the y-axis represents is water vapor here it is pounds of water per pounds of dry air but it's like to life it could be kilograms to kilograms it doesn't really matter it's a ratio and at a 10 percent relative humidity of 50 degrees there's a very small fraction of that 122 are 1220 grams of air per cubic meter that represents water it's only a couple of couple of grams are contained in the in the air at that relative humidity as the relative humidity Rises and you follow higher curves a higher amount of water vapor is being contained within that air volume so with that in mind what we're gonna do is we're gonna figure out in a little bit once we get this to a sort of a stable temperature we're going to figure out what kind of relative humidity we have to start with what we have to finish with and then we can calculate how much energy to remove that much water vapor from the what the air that were flowing through the system it takes over 2,000 joules to he condensed one gram of water so if we're trying to remove one gram of water per second we're using 2000 watts of cooling power and that can be even more significant than the effect on just cooling the air so let's give this a couple more minutes to equilibrate and then we'll start doing our our time lapse [Music] all right so obviously we've been going for about an hour and a half and as you can see we've dropped the temperature a few degrees Fahrenheit not that's not that impressive in terms of a temperature drop but one of the issues is that we're getting a lot of sunlight in this room we have huge windows in the back so we're probably pouring a couple of kilowatts of Sun into the room nevertheless the room is getting hotter it's actually getting a little bit cooler in order to determine the cooling power for the device I'm going to measure the temperature here on the output we're going to measure it across the input or the input and then we're going to measure it across the output and calculate how many watts is being extracted based on temperature so we've got about sixty two point I'll give it a little bit more time call it about sixty one point four and here still dropping and then what I'm gonna do is we're gonna use the Fahrenheit measures in order to look at the humidity but I'll change this over to centigrade so we can do the calculation of cooling power on the water on the air alone okay so let me change this over to centigrade 12.5 degrees centigrade and change this over to centigrade sixteen point six degrees centigrade so we've lowered the temperature about four degrees centigrade and because we are moving a hundred and forty five grams per second that means that we are essentially removing five hundred and eighty joules per second or five hundred and eighty watts per second watts of heat from the system air has a thermal inertia of one watt or one Joule per degree centigrade per gram so it's kind of easy to do the calculation so remember we used one hundred and seventy one watts to power this and we're getting about oh three and a half three point six in terms of the cop for the unit for just temperature reduction now if we look at the humidity we're gonna keep this at the Fahrenheit level because of this graph we'll go back to here and you remember that when we were at about sixty four and a sixty five and a half degrees we had about forty six percent relative humidity so in order to use this graph or we're gonna do as well start out with the original which is about sixty five degrees and we're going to look at the original humidity which would be approximately somewhere between the 40 and the 50 range which would be the brown line and the Green Line so if we trace this 65 degree Fahrenheit temperature up between the brown line and the green line you can see that we're right about here in terms of the vertical access if we trace that over here this says that we have about approximately 0.06 the weight of the air and the weight of the water and if we figure that the weight of the air is about one thousand two hundred and twenty grams that means that we have about oh 7.2 grams of water now if we look here we have a air temperature of about sixty degrees and if we trace that up to about 57 percent humidity which would be between the green and the yellow line right here and trace this over you can see that we're ever so slightly higher I mean it's very very close I would say it's almost in the noise because the lines are kind of fat but nevertheless it's clear that this system really hasn't removed much humidity from the air and part of the reason that it has not done so is because of this big wooden structure there's a lot of humidity that's absorbed into the wood there is the additional heating that's occurring because of the Sun which is hitting the concrete and that's also probably driving off a little bit of humidity the important thing though is we haven't added humidity with the process of this this test and so we could actually calculate the cop independent of reduction or addition of humidity and determine that we've got a cop of about three and a half three and a half cop is equivalent to a seer of 14 which is just right about in the range of a typical household air conditioning system the challenge in cooling off a large space like this obviously with a prototype system is that we haven't optimized the fans we have to deal with changing temperatures through the day it's becoming warmer both outside and inside and as we flow the air and the water through the system I've had to occasionally monitor to see what's happening with the fluid levels have to add a little bit of water to the system when I add the water it's obviously not refrigerated water its water from inside the room so effectively we're reintroducing some heat nevertheless it's pretty much comparable to a standard room air conditioner system in terms of its electrical use and as I said before the amount of electricity that we use is really the thing that we want to compare against a competitive conventional system because the sunlight that drives the desiccation process you don't pay for that it's free and kind of neat so I'm not overwhelmed with the performance of the system I think the prototype led me to believe that this thing would be just you know fantastic and it would blow away all of the commercial systems out there but nevertheless it is able to compete with the commercial systems out there without using any freon without using any without using a noisy compressor and having the advantage of a system that largely can be built by yourself you can put this thing together without having to have the skills to be able to solder and charge the system and evacuate the system you can do this with standard plumbing pipe so it's kind of a fun project kind of a neat way to spend the afternoon so I want to thank you very much for watching and I really appreciate if you would subscribe because we've got some really interesting videos coming up that are seasonal just like this air conditioner we push this to the September timeframe and it's already starting to get a little cool outside we've got a couple other videos that are coming up that also have to be completed before the harsh New England winters set on us and most of our projects are going to have to be located inside so we'll be posting this in a couple of days in another video a couple of weeks after that but again I thank you for subscribing and reading helps us out if you engage the channels with comments thumbs up that helps the algorithms with YouTube to promote the channel potentially even recommend the channel and our hope is to grow a lot bigger to help us to spend more time on more projects so I want wish you a very happy afternoon and stay safe have a lot of fun and enjoy your experiments see you soon [Music]

Channel: Tech Ingredients

Views: 1,464,397

Rating: 4.9214263 out of 5

Keywords: A/C, AC, Solar, Solar powered, Air conditioner, Air conditioning, Desiccant, Cooling, Calcium chloride, evaporative cooling, solar water heater, swamp cooler, duct booster

Id: 7w4rg3UcsgI

Length: 29min 56sec (1796 seconds)

Published: Fri Sep 20 2019

Reddit Comments

[u/I_Zeig_I]

Have t watched this yet but this guy is awesome. I aspire to be him lol.

From the thumbnail it looks like a geo-cooled system?

[u/Babou-is-a-Tunt]

“and in the column, you have a common shower head. This is ..uh... a two dollar... uh.. human being shower head.”

I like him.

[u/slackbook]

thumbnail looks like a bong

[u/xLavablade02]

I used the heat to destroy the heat

[u/Benjigga]

I wish I were smarter.

[u/Leftfielder303]

One aspect of it is solar powered. The majority of the work is done with the pumps and fans and they are not solar powered directly.

[u/Blackfire12498]

Bong from the future

[u/Apacelull]

Did he calculate the area of the circle wrong? I'm confused.

[u/EchoTab]

That is brilliant, ive been looking at some other videos of him now and he is a pure genius, really interesting videos. I wonder what his background is.