This article presents a do-it-yourself project to create a low-cost ventilator using Arduino, including integrated temperature, BPM, and oximeter functionalities. The project is based on the idea of a DIY emergency ventilator that automates the squeezing of the bag, typically built using off-the-shelf parts and widely available materials. The project aims to provide a reliable yet affordable solution for Covid-19 patients.
To make a DIY low-cost ventilator with variable BPM and BLM, blood oxygen level, and lung pressure, one can follow these steps:
Wire up the electronics: Step 1: Wire up the electronic solenoid valve. Step 2: Upload Arduino Code and Test Electronics. Step 3: Attach Barbed Tube.
Make a positive pressure ventilator: Step 1: Parts. Step 2: Spring Out. Step 3: Mount Bellows. Step 4: Motorize Pump. Step 5: Exhale Valve. Step 6: Connect Hoses. Step 7: Prepare.
Learn the internal mechanism and working of a Ventilator with a DIY make it yourself ventilator with SPO2 sensor for automatic ventilator system by Arduino. The ventilator will be designed and developed using Arduino and esp8266, providing many functions and being a reliable yet affordable DIY Ventilator.
Home appliances firm makes ventilator for coronavirus patients: AFP.
To make a DIY low-cost ventilator with variable BPM and Oxymeter, one needs a linear actuator, such as a 4″ Stroke Premium Electric Linear Actuator with a 12V power supply.
📹 How To Make DIY Low Cost Ventilator With Variable BPM & Oxymeter
Check out the Making of a DIY Low Cost Ventilator With Variable BPM and BLM along with blood oxygen level & Lungs pressure.
How much does a ventilator cost per day?
The daily use of a ventilator in hospitals increases healthcare costs by an average of $400 per day. This increases the patient’s length of stay and other costs related to monitoring and support. Long-term complications from mechanical ventilation include slower recovery time, physical disabilities, cognitive dysfunction, and psychiatric issues like anxiety, depression, and post-traumatic stress disorder. These complications are associated with long intensive care unit stays and the use of a mechanical ventilator.
Can you live with 70% oxygen?
Low blood oxygen levels can cause organ damage, including the heart and brain, and can be fatal. COVID-19 patients admitted to the hospital with low oxygen levels are typically placed on a mechanical ventilator. Low oxygen saturation levels during sleep are linked to various health conditions, including double the risk of depression and a possible predictor of cardiovascular disease mortality, especially in older men. Studies have found that an average oxygen saturation rate below 90% during sleep can be linked to various health conditions.
What is the cost of a ventilator at home?
Ventilators are machines that deliver breaths to patients who are unable to breathe or breathing insufficiently by moving breathable air into and out of the lungs. They are computerized microprocessor-controlled equipment, but can also be ventilated using a simple, hand-operated bag valve mask. Ventilators are commonly used in intensive care, home care, emergency medicine, and anesthesiology. They increase oxygen levels in the lungs and remove carbon dioxide from the system. The price range for ventilators varies, with the minimum price being Rs. 118000 and the maximum price being Rs. 1784160.
How to create ventilation in a closed room?
This post discusses 10 ways to improve air circulation and ventilation in windowless rooms. Air conditioning is a popular solution, as many people are looking to use small and underground rooms in their homes. However, windowless spaces can be more challenging to ventilate due to the lack of fresh air. Air circulation is less of an issue in moderate climates and open plan spaces, where stale air is less likely to get trapped.
Instead, consider using extractor fans, grills or ventilation fans between rooms, temporary ducts, leaving doors open, fans, perforated building materials, and portable evaporative coolers. By considering these solutions, you can improve the air quality and overall health of your space.
Can you have a ventilator in your home?
Johns Hopkins Care at Home offers home ventilator services to help people manage their respiratory conditions from the comfort of their homes. The services are available to people of all ages in Maryland, Virginia, and Washington, D. C., and require a referral from a provider. The respiratory therapists have extensive experience in caring for adult and pediatric patients with breathing complications from conditions such as lung disease, amyotrophic lateral sclerosis, and multiple sclerosis.
Can you buy a ventilator for home use?
Home ventilators are smaller versions of hospital ventilators, with key differences such as being more compact, portable, and having a longer-lasting battery. There are four primary types of home ventilators: CPV, LVV, LVV, and LVV. CPV is a portable device, while LVV is a larger, more portable device. LVV is more suitable for specific needs, so it’s essential to weigh each device’s pros and cons with your medical team. Understanding these differences can help you choose the best home ventilator for your specific needs.
Is there a portable ventilator?
The EMV+® portable ventilator is designed for military transport and is ideal for air medical and ambulance transport of infants, pediatric patients, and adults. ZOLL ® ventilators are user-friendly, providing on-screen prompts for efficient oxygenation and treatment. They feature Smart Help™ technology for alarm resolution and Masimo ® pulse oximetry for accurate SpO 2 and pulse-rate readings. The Z Vent ® portable ventilator is rugged and offers a full range of ventilation options, making it easy to use and MRI-conditional, providing high-quality ventilation for patients up to the MRI suite.
Can a person breathe on their own with a ventilator?
The next step involves a test for breathing with a reduced amount of oxygen support. The ventilator is not disconnected, but the settings may be adjusted to allow the person to start breathing independently. Healthcare providers closely monitor for signs of difficulty breathing naturally, similar to the SAT test. If the person needs to return to sedation, the SAT and SBT process will be repeated the next day.
If the person passes the breathing trial, they are then removed from the breathing tube, known as extubation. The healthcare team adjusts the bed, asks the person to take a deep breath, and then removes the tube as they breathe out or cough.
What is the lowest oxygen level before death?
A SpO2 level of 92% is considered the lowest clinically acceptable level, except in cases of chronic lung disease where it is 88%. Hypoxemia can lead to death at any level below 88%. Sustained blood oxygen levels below 80-85% can be life-threatening and can cause severe complications or death if not promptly addressed. If oxygen levels fall below 85 percent, serious symptoms of hypoxia can occur, leading to injury or death.
In oxygen levels below 65 percent, mental impairment can occur, and consciousness loss may lead to death. At 10 percent, survival is only minutes or seconds. Factors such as altitude, heart and lung health, and the body’s ability to receive sufficient oxygen are crucial for survival.
At what oxygen level is a ventilator needed?
Normal oxygen saturation levels range from 94-99, and a drop below 93 indicates the need for oxygen therapy. This therapy is beneficial for patients with pneumonia, ARDS, dyspnea, or hypoxia. Current clinical management guidelines suggest supplementary oxygen can be administered at home or in a hospital setting, depending on the patient’s condition and symptoms. Oxygen support may be extended based on the disease’s severity.
Can we setup ventilator at home?
Long-term ventilator use can improve quality of life and avoid complications from long hospital stays. It is typically used with a trach tube or face mask. Some people may need ventilator support for life, while others may stop using it when their condition improves. For example, a child recovering from a chronic lung or heart problem may be able to go home on a ventilator. The healthcare team will determine if the individual or child is ready to stop using the ventilator. Before leaving, the team will teach the patient and caregivers how to use the ventilator.
📹 I built the best DIY heat recovery ventilator I’ve seen on YouTube
I built a heat recovery ventilator (HRV) from only sheets of corrugated plastic and adhesive. EDIT: SEE PINNED COMMENT for …
please assemble many machines …i beg sir…i beg….we really need your help…you are our only last hope sir…please… I as a student request you ..I myself am ready to buy them….just show me a sign that you are ready for this social cause….and stand for the Man kind….My all prayers and hopes for your positive reply
IMPORTANT UPDATE: I did some more efficiency tests in the spring using the outgoing air and it seems that my HRV is actually around 60% efficient (which is still pretty good), not 85%. I wanted to make a article about this but I ended up having to put it on the back burner because I went through the process of selling my house. When making this article, I made the mistake of testing efficiency using the incoming fresh air. I think that heat generated by the fans skewed the results. Here’s a formula I used for a corrected efficiency test using the outgoing air instead: × = (T_room – T_outgoingAir) / (T_room – _outdoors) An example of one of my test runs (Fahrenheit): 60.5%=(70-44)/(70-27) So yeah, it is less efficient than I initially thought. That being said, it still worked quite well. I want to address some questions I’ve seen: I do think that almost all of the air is flowing through the core. The filters were quite dirty when I dismantled this HRV, and in order for them to have gotten like that, I do believe air must have passed through them/the core. I don’t think there is very much leakage in the chambers. I sealed them very thoroughly with hot glue and weather stripping, and did leakage tests. I acknowledge that there could be some leakage, but not that I could find. Next point, to the couple people who quoted Egon Spengler at me: no, I don’t believe I’m “crossing the streams” (intake/exhaust air streams mixing). After this article came out, I installed elbow duct attachments to the indoor supply and outdoor exhaust to the direct the air streams away from the intakes 🙂 Potential reasons I didn’t run into condensation issues: lower HRV efficiency combined with the low dew points in my house (from ventilation with dry, cold air + no humidification).
New subscriber here!! This is the best design I have seen on the Tubes my friend!!!!!I am starting a gourmet and medicinal mushroom growing business in Delaware with my best friend/business partner and I have been researching ways to reclaim heat and use alternative methods of heating and cooling. I developed a device that collects and. inverts electrostatic electricity from the atmosphere and converts it into usable dynamic electricity. I need one part to finish the design but it works . I am designing ot so that it can work with off the shelf transformers and such . The last part I need it a triggered spark gap and to buy one is expensive. I bought a lathe but there is a learning curve on it….
As an HVAC guy i can say your design although unconventional and bulky is just fine, your fans you use for circulation would benefit from the coandâ effect to increase air flow. Also those efficiency rating the big companies use are totally skewed so your system is probably working better than off the shelf systems thanks to that massive core you built
Love it, considering buiilding one of these for my home too! You could have used half the correx by using double sided foam tape to create the core, with one website being formed by taping two sheets together. (using tape with a thickness similar to the height of the plastic sheets) this has the advantage of also reducing the thickness of plastic seperating the air websites, so heat transfer should be more efficient. (as it would be one layer of plastic rather than two layers plus glue) Also a dual core design could improve efficeny by doubling the surface area for heat transfer.
Dude you are brilliant, it never would have occurred to me to use the natural tunnels inside of coroplast board! That’s legit mate. You’ve managed to achieve very near the efficiency of commercial units that cost thousands of dollars. This is such a great idea, you’ve given me all kinds of ideas for my own apartment.
If you’re chasing every last % of efficiency you could make your own fine website aluminum heat exchange core. Get two or three Fiskars 9340 paper crimpers with metal crimp rollers. The rollers are the parts you’ll want, to put together end to end on a common shaft because they’re only 6.5″ long. Might need to double up on the crimpers if only one roller in them is aluminum. You’d have to build a custom frame to hold them and add a long hand crank. For metal, whatever thickness is used for offset printing plates would probably be ideal for the corrugated website sheets. To separate the corrugated sheets use heavy foil, the thickness used for single use turkey roasting pans ought to do. I’d expect thinner to be better for heat transfer. Can’t go too thin on the corrugated sheets gauge because the core would need rigid plates on the sides and a way to compress it to ensure good contact between the corrugated and flat sheets to block bleeding of air between in and out paths. It would have to be more efficient with heat only having to cross one very thin, highly heat conductive sheet of heavy aluminum foil VS two layers of plastic that don’t transfer heat anywhere near as well as aluminum. Any bet it’d be over 90% efficient at heat transfer? Fiskars makes a wavy version of the crimper, model 9341. Wavy websites would make the air slower, with a longer path through the core, but those crimpers look like the crimp rollers are all plastic.
Very cool. 🤔 I like the idea of a charcoal filter, but I’m clueless where you would put it in the system. I’m building my retirement home in Arizona (a cute little hacienda style cottager) and I want to incorporate as many DIY solutions, and revive as much ancient technology as possible. Thick adobe walls will go a long way towards providing the thermal mass I’ll need in the desert to moderate temperature swings. I think instead of the plastic body you could use ducting sheetmetal or the smooth fibreglass boards used in commercial kitchens, hospitals, etc. Both materials would give the same smoothness, but would be a lot more robust. Mine is NOT going to be proudly displayed in the living room! Sorry, although I’m now retired, you can take the girl out of the interior design business but… I plan to properly tuck it away in a conditioned attic space and cleverly vent the clean, temperature-moderated air throughout the house in inconspicuous or decorative ways. Can’t wait to binge-watch some of your other articles.
Now that your article is 6 months old have you inspected and cleaned the cleaned the HRV and particularly the core yet? One of the biggest hidden dangers of HRVs is that they require maintenance which could easily be skipped and result not just in decreased performance, but also mould growth in the core which would negate your efforts to improve air quality. You stated that your core is horizontal and hence is not able to be drained and that you didn’t expect any difficulties due to your climate which may be a correct assumption, however the only way to know this is empirically. I would be very interested in the results of an inspection. Thank you very much and all the best.
Hey mate, that’s already on my diy project list, I am evaluating different materials for the heat exchange unit and currently the best choice from my point of view is aluminum as it has the best heat transfer rate and is already available as foil. That should bring the efficiency somewhere around 95%…what’s your opinion? I was very happy if you could provide some statistics about the air quality over time with switched off device and running in different power modes like e.g. being alone in contrast to many party people, cheers and stay healthy 🍻
Drainage – I don’t believe that you need a big slope to ensure that water will drain. You may need to balance the wetting of the surface with the size of the passages so that the droplet sizes (should they form) don’t block the flow. And just because the exchanger flow may pass the dew point, doesn’t mean that there is energy exchange available to cover the latent heat part. You’ll need to try it in a shower room (warm wet air) with exchange to a cold wet rainy exterior….
If your HRV actually is 85% efficient you should get a lot of condensation when outdoor temperature is below freezing. You can figure out the dew point of your indoor air, and unless that is as low or lower than the expected temperature of the exhaust air there should be condensation. The “fresh air” you get is definitely a mix of fresh air and indoor air that leaked into the fresh air stream, possibly not in the core, but definitely in the giga-supersized chambers outside the core. Also you need to make sure the flows doesn’t mix outside to get an measurement of the actual efficiency. If you measure the temperature that leaves the house, on the outside, instead of the mixed airflow, and compare that to indoor and outdoor temperatures you can find out the actual efficiency. The actual efficiency is definitely not anywhere near 85%. Aluminium conducts heat around a thousand times better than most plastics, and you can make aluminium much thinner, which also improves heat transfer compared to plastics. You even have two layers of plastic, and a layer of adhesive, and possibly areas with air too. And no way those fans can force hundreds of CFM through that core, a powerful leaf blower might be able to do that.
Honestly making this from plastic is pretty dope in terms of cost. However you could make it MUCH smaller. I have a lot of those plastic sheets lying around for different purposes. Also you’re using layers of plastic in 2 directions, which might lower the performance because it has not amazing heat conductivity. Just one set with gaps would be perfect. This is high static pressure application, so in this case, it would be best to get 2 centrifugal (radial) fans, not axial ones. It would also make sense to make the heat exchanger much longer, and thinner, to get full heat extraction. Great article though. Nice design.
This is unbelievably cool, even with the potentially lower efficiency number. I just bought a house and have a 1990s furnace that I want to keep running as long as possible. Currently in the process of cleaning and sealing the duct system and trying to DIY as much as possible. The furnace uses a long insulated flex duct to allow unfiltered cold Canadian air into the furnace room for combustion. I feel it’s very inefficient (and dirty) to have a clear line of outdoor air entering my home. Your system seems like the perfect DIY method to address this problem. Just found your website and looking forward to seeing what other ideas you have.
Bro, you would put a little greenhouse lean-to against a southern wall of the house outside the window to actually heat your house on sunny winter days. Also, you could just skip the return fan and suck air in and make your house “positive pressure so that you leak a little air outside rather than allowing dirty air from outside to find its way into the house
Thank you for sharing this, truly. Definitely a thumbs up! Sharing knowledge and experience like this this is the internet at its best. Also nice to give credit to your sources at the end. Question 1: High effective is 85% as compared to a commercial system? I could do my own research of course but in case somebody knows already … Question 2: Did you consider alternatives to spray adhesive for laminating the plastic heat exchanger stack? I am thinking it is an unnecessary source of VOC’s? Are there “healthier” adhesive options or am I being overly concerned? Question 3: Would efficiency increase with a heat exchange filter material of greater thermal conductivity like copper or aluminum? A am pretty sure moisture build up would be an issue if installed “properly” with outgoing air coming from high air moisture areas like bathroom, kitchen and laundry rooms however. But in any case really cool build!
This is great! I wake up every morning and my bedroom smells like crap.. Sinuses and nose at winter are always kinda gunked up … Every time i get ill in the winter months is always the same symptoms, sinuses, nose and throat full of awful fluids that i have to spit out…..I think all the bad fluids wanting to go out from our lungs and throat is way of our body to clear and flush all that crap out.. Im 100% sure that air quality plays a massive role in that respiratory system. I dont mind opening window for a fresh air multiple times a day but at winter its kind of waste energy and also when it gets cold outside air is crap to! Cause here in Serbia a good bunch of houses still uses wood and coal to heat their homes… here the market is so terrbile that small home HRV’s are basicly non existant and the big comercial stuff is to expensive.. Your build rly goot me thinking, looks simple to make and i could put it on my attic and duct it down in the house like a cealing vent. Curious to see whats next .. Would like to see how you tested efficiency, what was the indoor temp and intake temp of the fresh air and stuff like that. Greets from Serbia.
I applaud the initiative. This is certainly the future & I love it. Some things to consider… 1) CO2 “cannot” be affected by the unit, as the CO2 level is whatever you are drawing out of the air coming in from outside (usually about 400 unless something weird is going on. Plants like it when we “talk to them” because we are breathing CO2 at them. CO2 builds up in a house because of “us”. 2) I would be greatly concerned about the VOCs coming off all that plastic, adhesive and other chemicals from 3-D printing. It’s gonna off-gas, a LOT! Funny your comment, “insane!”, right after, cause…, yeh. 3) There is an actual Metric they use, CFM/watt, to quantify how much actual work is being done. It’s used to measure performance. Measuring the Factual temps of the airstreams is of great interest also. 4) Tape the edges of the filters or there is bypass (sneaking around the filtration, around corners). HEPA has no “bypass”. 5) Measuring the air pressures will tell you the static resistance various parts of the system are causing – core, filters, vents. Cool experiment, but don’t mislead people with hyperbole instead of data. Maintain integrity. Do no harm. Cheers.
Impressive and inspiring, thank you. For someone interested in trying this, why coroplast, other than it comes pre-corrugated for maximum surface area? Wouldn’t metal plates work better at transferring heat? (but much more time-consuming to pleat by hand). Maybe the fins from old A/C and HVAC equipment can be repurposed for this. Amazing effort and spirit, blessings and apprecation.
Chloroplast may work, and you appear to have built this one sufficently large to get fairly good efficency at the rate of air exchange. But, know this. Plastic is inefficientl at moving heat across a given surface area. Your heat exchanger could get comparable efficency with a smaller design if the core were made of sheets of aluminum seperated by small three or four spacers each layer. Or you could achieve significantly higher efficency with an aluminum core built to to your existing core size.
Oh k, so without the data from before. Using your little couple together thing there. all data, claiming that it’s a reduction. And whatever means, absolutely nothing. Let’s see the data from before you put this in your window, and then there’s a lot of other things that you need to take a note count. What’s the age of the house? What kind of heating and air conditioning system are you using in the house? Have you cleaned the duckwork in your house? I like your design, but we need more information.
Hey. Nice article. I have a few questions if you don’t mind fielding them. I also have a few tips. I use a similar Panasonic unit, but I made modifications to it (some similar to what you made). 1. It looked like you had a filter for your exhaust air (right before the air entered the heat exchanger core). Was that to prevent dust from getting into the core and clogging it up when the walls of the tubes got damp? 2. I either missed it or you didn’t say. Did you lay the sheets of corrugated plastic at alternating right angles to each other as you stacked up that core? Cool idea. For tips, you should DEFINTELY separate the intakes and exhaust vents as soon as you can – especially for the inside outlets. I’m sure you’re immediately dumping a fair bit of your newly pumped in fresh air. As soon as you can spread those apart, do it. If you have a radon issue in your house, consider grabbing the air to exhaust from down in the lowest part of your house. If you have any occasional smoke (like from a fireplace), consider grabbing air to exhaust from up high where smoky air rises to. Overly humid bathroom would be a good place to collect waste air too. You get the idea. Consider dumping fresh air where you want things to dry out. Mine dumps over my kitchen sink where I do dishes. The dishes dry in no time. That wasn’t planned ahead of time, but it’s appreciated. Those fans are awesome by the way. I use those for venting air all over the place. I use that exact 6″ model for running hot air under my concrete floors to warm them like old Roman baths used to.
Wow! Your did great! You did a great job! And so efficient too! I live in a very small home in CT, a 200 yr old home, I renovated 20 yrs ago. Our home is 24×22, with basement, 1st flr, 2nd flr, and walk up attic. It’s a post and beam kinda house. I installed ductwork, and Air handlers, one in the attic to service the 2nd flr, and one in basement to service the 1st flr. I have a boiler for heat, so it is a hydronic system. Each AHU has a hot water coil, that way I can also temper the discharge temp. So I think about 5 yrs ago, I added a Fan tech ERV to my 2nd flr setup. I added external filter boxes, with I think Merv 12 filters it came with, cause you need to keep that core clean as well as the air we are gonna be breathing. This was the lowest price unit at the time, and the enthalpy core is same product you used, but not as nice as yours, mine is not very efficient, so on really cold days, I don’t use it. But a year later I bought a HRV for the basement I spent a little more and got one a bit more efficient. (I’m not rolling in $) I have seen some really high efficient EVR’s but big $. I’m fortunate I inject the “make up” air into my air handling system. I also have UV-C lights in the AHU’s. I have my 2nd floor ERV set up so when I run it, a relay turns on the FAN mode on my t-stat, so the AHU is running to distribute the air when the ERV runs. I have a Timer so 2nd floor runs at night (bedrooms all on 2nd flr) but also another timer called an Air cycler. This means it will run say from 6pm to 8am, but the air cycler runs the system 15 mins every hour.
I have an existing HRV that is starting to show it’s age (getting noisy) and replacing the fans would be something like 1200-1500€ so I am thinking about getting a new one. Doing some DIY work on it with third party fans is something I have been thinking about, but the original fans are custom built and I have been unable to find duct fans that I can properly control. The originals are radial fans and built specifically for the HRV…
Great article! Is there anything preventing this HRV from being positioned sideways if a stronger material is used to support the core? Perhaps wood? Or would you suggest keeping it horizontal and using ducts to direct flow vertically? I only have a thin vertical window. Context: I’m planning to move back to my dorm which I’ll be staying at during colder months and need a college student solution to keep CO2 down
Very cool. I’d love to see a full build article with parts and dimensions. I’m already wondering if I could fit this in the top of my entry closet. It’d require drilling holes in my exterior wall and the closet wall, but it’d solve the obstruction and looks issues here. Also curious to see the process of changing the filters. If you have to open the top for maintenance then this install location might not work (though I guess you could put it on the floor of the closet instead).
I’m going to have to build my own. After updating the insulation in a hunting shack, it’s too air tight. These massive units are too big for a 12×12 single room space. The mini or single room “HRV” units being sold, have fresh air intakes right next to their exhausts like bathroom fan style HRV’s, which is an obvious and embarrassing engineering flaw.
Clever to recognize coroplast as a useful material! Its thermal conductivity would suck compared to metal, but if the dwell time of the air inside then heat exchanger is long enough, that will compensate: Half the conductivity? Just double the dwell time. 1/4 => 4x, etc, etc. It seems the duct fans are working fine for you, but a cheaper and potentially better solution could be a used squirrel-cage blower from an HVAC system, with the speed adjusted via either a cheap A/C speed controller (triad plus noise filter) or by putting a small motor on it, running it via a timing-belt setup (the kind of timing belts used for 3D printers. Squirrel cage blowers are great when dealing with back-pressure from filters or the stack itself.
I think the main thing stopping you from having better efficiency is the cross-flow. Your two airflows are perpendicular to each other, and you can get better heat transfer by having contraflow instead, where the airflows are in opposite directions. However, that makes construction slightly more tricky, and probably can’t be done with the materials you are using, as the airflow needs to change direction in the middle of the core, and the core needs to be longer to have that contraflow section in the middle. I’m considering making a unit with (very cheap) aluminium foil, but I’m not 100% sure it is durable enough.
What I need an HRV/ERV for is to lower the CO2 levels in our very air tight 1100sq/ft home with propane cook surface, 2 adults and 2, 80lb dogs. The CO2 levels quickly rise to over 2000 PPM without exhaust fan running and periodic use of the whole house fan with doors open. High CO2 levels cause headaches, drowsiness and other health problems. I bought a quality Ambient Weather indoor AQI monitor which tracks 2.5micron and 10micron particles as well as CO2 levels with reasonable accurance and was shocked at the dangerous CO2 levels we were living with.
How are you measuring the efficiency of this? Im not convinced by any of this. You have lots of gaps in the coroplast box which will easily allow the pressurized air to exit before they do their expected travels through the merv filters which will bring quite a bit of resistance along the way. Its going to be much easier for the air to just… escape.
I’ve got a room I use for 3d printing. Resin and filament. I’ve been doing research and I think the fastest way to have better air is to replace it rather that strictly filtering the air. Do you think a system like this would be a good use for a room like this? Ultimately I would like to have air intake going through the wall rather than through a window. Also does the height matter? Like would having it lower work better than having it higher closer to the ceiling? Would be so awesome if I could get a response.
Condensation within the unit will be a problem in most climates and when heating or cooling the incoming air. Over time the heat transfer plates will grow a biomass that can (in extreme cases) include dear old Legionella – the bane of commercial air con units. So a unit will need a means to drain condensate to a waste, and a way to periodically (say annually) disinfect / clean the core.
Man I’m absolutely blown away. You did an amazing job. Well done on your research and execution. I have a whole new view on heat recovery systems now. In HVAC, these items are extremely expensive. I don’t often get to specify these due to clients not having the budget for it. After seeing your results though, I think I can come up with something affordable and efficient on a commercial scale. I feel efficiency can be improved with a quick material study. Thanks for your article. I’m very impressed and appreciative for you helping me see how simple this system can really be.
This is a great article – I’ve liked and subscribed. But your discussion of costs are a bit misleading. You say installing a new unit would be $4000 dollars and whereas it certainly could, there are models that only cost ~$500. Labor cost should not apply here since you also did not install this into a dedicated mechanical space with duct work. Still, assuming you could get the cost down to $150 by sourcing cheaper suppliers then it may be a worthwhile project.
Well done and nice and cheap. I well remember last century, pre internet, someone had constructed a very efficient HR unit out of pleated paper! Large pieces of paper, folded about every half inch or centimeter and laid cross ways like your core flute and connected just the same as yours. The paper being thin, had excellent heat transfer properties and low impedance to air flow. Question would be, how would it go in high humidity? Maybe spraying with a mixture of something non toxic but hydrophobic would be the answer. Plant wax? I’d say your set up would suffer losses because if the poor heat transfer of the double layers of coreflute. I have seen single sided stuff around. That would improve efficiency. Maybe single sided corrugated cardboard would be the go?
This is exactly what I was looking for!!!! I have a Resin printer that I want to exhaust out of the room, but I don’t want to lose all the heat or cool air in the winter/summer. I hope this works for me! I don’t need to change much air, just a little bit, so I bet a 4″ fan set to low would be enough for my application. Great job!
This is amazing. I now think my son should have this in the little room he sleeps in with the door closed all night. He’d be freezing with the window always open, but he has allergies and could use the filter. Plus I can imagine that CO2 levels rise in a tightly-sealed, unventilated small room with someone breathing all night. Hmm. You have me really thinking. I need to get your recommendations for the right instruments to measure air quality. Oh, and you really are sounding less allergic. Nice!
Great project, even if the efficiency did not quite measure up. I would argue however that anybody building one to install in an older home should dive deep into already existing air infiltration issues. Just a few poorly sealed holes in the framing can cause a hidden issue through the entire home, even through interior walls over crawlspace construction. The pocket hole doors originally built into my home permitted an absolute blast of air through them when the house was pressurized, much of it likely coming from the crawlspace. (I sealed the pocket doors in entirely.) Even the catch on the jamb for a door latch became an obvious breach that a little caulk easily fixed.
Hi! First of all, that is a very nice and elegant work. I am very interested on how you made the exchanger itself. Do you have a article about it or at least could you share a bit more information about it? (Edit: I just saw your reply to another comment, I will check the article. Thank you for providing the information!) I do have one criticism which I hope you will find constructive: the way that you are measuring the efficiency is slightly off. You are basing the efficiency computation on the temperature of the incoming air instead of the temperature of the outgoing air. It does make a difference because the incoming air has the energy recovered from the outgoing air plus the heat generated by the fans, leading to an overestimation of the efficiency. If your fans were generating heat like crazy, your measurement method would conclude that you have an extremely high efficiency, which would be inaccurate.
Great work! I’d place in the attic or at least that is what I planned to do with mine. I assume you saw the Hackaday HRV and maybe also my comments there and his youtube articles. I bought a few rolls, and even got some for free, of aluminum window screen. The thought was at some time 3D printing or maybe CNC in wood a tool and die to stamp like a linear ridge zig zag stamp so to increase the surface area of the alternating layers. I also found an old hair iron crip wave thing that is close, though small. I plan to only space the one path of flow and use corrugate on the other path. The spaced path that would use two other maybe three strip of one width corrugate tubes would have the zig zag aluminum mesh. I left off wondering how to plastic weld both sides into the full sheet of corrugate. The other thought was just ironing into both side of the corrugate the aluminum screen. That might work suitable as well and just then placing the zig zag screen into contact. I probably should work on again since I have now another size of corrugate material, 4mm, and not only the cutout 12×12 inch larger thickness 10mm corrugate. What thickness corrugate did you use? Thanks for sharing. Great to see more of these designs being made successfully and cost effectively.
That’s an interesting design. I’ve actually seen a very similar design (using coroplast) from an HVAC company that fleeced me thousands of dollars some years ago for an HVAC design that included one of their custom ERVs. I got suspicious after seeing that they didn’t have a test in HVI database, and after seeing the docs that they sent me, it literally showed 0% humidity recovery for their “ERV”. Which made sense, since this type of design is non permeable and cannot recover humidity, making it an HRV only solution. Didn’t have the time nor energy to try and get my money back.
Thanks for this article! I think that you could make that box into a vertical version if you used plywood for the largest sides. It would not need to be more than 3/8″ thick to support that core. Probably 3/16″ would do. I bet masonite or “bath-board” (which has a nice finish on one side) would work very well. Adding some 1/2″x1/2″ wood pieces in certain corners to further stiffen the housing would help as well. (even if using your current materials for the walls) I think that you might get more efficient airflow if you used some internal ducting to reduce turbulence between the air inlets and the filters and the air outlets and the core. (The shape of the chambers the air passes through is probably causing a lot of turbulence) A piece of thin poster board could be formed into a cone that is the diameter of the inlet at one end. The other end could be creased into a square to fit the filter or core. (the circumference of the filter/core end should be equal to or slightly larger than the perimeter of the filter/core in order to fit) That would give you a custom duct for very little in the way of expense and effort. Another good material for this would be a used printing-press plate. They are usually aluminium and can be gotten at any place that prints posters etc on a lithographic press. A layer of radiant-barrier material (like ArmaFoil from EnergyEfficientSolutions d0t c0m) over the block in the window and on the inside of the walls of the housing of the HRV would insulate the system and increase the efficiency a little more without adding much bulk or weight.
Really nice work. You’ve mentioned your HRV’s size, (07:56), which got me thinking…. the ducts, fans, filters, and heat exchanger must stay about the same size to meet your needs, but eliminating everything except for those essential parts, should reduce its size by at least half, maybe more. Alternatively, installing your HRV out of sight, like outside, or in the attic, should leave only the intake and output duct holes visible inside the house. Good luck, and thank you for sharing.
Hello, condensation will not be possible unless you are adding a lot of water vapors to the air in the house. Just taking cool air from outside and heating it up and cooling it again to roughly the same temperature (not cooler than initial cool air from outside) will not cause it to reach the dew point and condensate. Maybe if you are boiling water 24/7 that might cause condensation but only when outside air has 100% humidity. I do have a question, why are you filtering the air that is going outside? shouldn’t you have both filters diagonally for the fresh air from outside? Replacing the plastic with thin aluminium foil might reduce the cost and increase the efficiency, to almost 100%. But that would require a different design, I can describe if you need but it’s a challenge to explain.
I’m looking into this myself as I’m struggling with keeping the cat litter smell at bay now that I have two cats, and great to see that this design with the plastic actually works well. I would have figured it would not have enough thermal conductivity. I might have to experiment with this and see if it will help. Right now I’m just opening the windows but that won’t exactly be an option in the dead of winter!
I had an idea that might make the core better: What if you would have Coroplast thickness bigger for the exhaust than the supply, then take like a 0,60mm copper wire and go in between every hole, since copper better conducts heat it should keep the core warmer, while the thinner Coloplast is on the supply, which makes the air pass slower through the cube. You have all the measuring stuff, so you could actually see if it makes a difference. But I don’t see how plastic could be better than copper in heat conductivity.
Great design bro! This should work damn well for your money! As an engineer, I am pleased to hear competent technical reasoning accompanied by such a simple but ingenious design.Bravo. Physics does not work on the loud brand and price of equipment, but on the principle. You inspired me not only to make a similar device for myself, but also to think about the serial creation of cheaper systems.Where I live, such systems are not financially available at all. Everyone deserves to breathe clean air.
very nice… i think i may make one out of aluminum sheets or sheet metal which would transfer heat more efficiently. granted it would be more expensive but i think a bit smaller and a more efficient unit would be worth it since the ones you can buy are so damned expensive. due to a lot of forest fires here in the west, i was thinking of having filters on mine already and i like the way you placed the filters. i want to have more surface area, however. my filter design is its own separate box consisting of 5 square filters mounted on a 6th plate making a box that has 5 filter sides and the 6th side would have a duct fitting to provide filtered air to the hrv. i think those filters can be of the cheaper variety pre-filtering the air and have the higher quality filters in the hrv as you have them. that should allow for the cheap filters to get the larger particles and extend the life of the finer filters and improve air flow.
When talking about HRVs, the topic of CFM and ACH (air changes per hour) should be covered. I arbitrarily sized your house at 1500 sq-ft with 8ft ceilings = 12,000 cu-ft of volume. I estimated your airflow at 100 cfm. I came up with 2 ACH (air changes per hour). The thing about fans is, they rate their CFM on zero static pressure. But this unit will definitely have a relatively high static pressure, therefore the CFM of your build will be much lower than one might expect. You’ve also said in other comments that you’re lowering the fan speed. In order to determine your actual CFM, you could just multiple your working air velocity (in ft/min) by the duct area (in sq-ft) and calc the CFM.
The deal breaker for your design is complexity. Once you go above the 100USD range, ignoring work, you start competing against SEA manufacturers which use aluminum and already more integrated cellular designs, which typically use a hexagonal “core” (It’s really the entire thing, at that point), which reach +90% efficiency and allow for much faster airflow. Their only downside I see is the lack of filter integration, however, you could simply duct the intake to attach a filter or go the extra step and build a more adequate case, possibly with the same materials you are using. Either way, I enjoyed your project a lot and I hope it servers your purpose well! I also think you might enjoy “Tech Ingredients”
I’d like to see measurements at a different location, behind fan is not properly done fan gives away heat there for infront of it. Probe in the exit chamber (from intake side). Fans generally creat heat them self. An other suggestion add tinfoil sheet to every layer in the exchanger they will increase transfer rate and add some thermal mass. An other concern is that duk are to close short way of exchange air(tight loop) . Pipe to the other floor? So air is going thru the longest way apart/ separated . No extra fan needed for separate rooms? For even colder outside temperatures add a singel direction layer in the box ( intake chamber) holes from lid to bottom pipe from hot air in room by the sealing just passes in the box with a fan. Same method for cooler summer air uses opposite coldest basement floor air as a pass thru one direction to cool intake air.. Pre air website balancing pass port, circulating room air based on outside temperature. Best regards J
Maybe you just need to get outside more often…. Maybe you should move out of the city where the air is nasty and maybe you’ll experience a better quality of life… I live in the deep country and I use my house for sleeping, otherwise, I’m outside enjoying peace and quiet, fresh air, and nature…. People are building houses these days to stay cooped up in them 24 hours a day… What a wasted life!