Fundamentals of Energy Recovery Ventilators (ERVs)
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- Опубликовано: 25 сен 2017
- Not sure how an ERV actually works? It seems magical, but it actually fairly simple. Join Ryan Hoger as he walks us through one.
Music by www.bensound.com 
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The best explanation I’ve seen of this technology!
This was an excellent presentation with a live demonstration. Cleared all my doubts.
This man offers high level presentation great video production
Finally a demonstration that I could understand. Very well done, thanks!
Great demonstration. Surprising how well the heat transfers. Thank you!
I've been trying to fully understand HRVs ERVs for months and although I got to where I understood what they did, I had no idea of how they did it. Of the dozens of videos I've watched, your video is the ONLY one I've found that gave me the information I wanted. Excellent job!!
Thank you. If you want to dive deeper, we did a 1.5 hour webinar on this same topic today. You can watch it at attendee.gotowebinar.com/register/3857937118863671564
@@TECTubefilms
Awesome! I'll definitely check it out, but it will be 2 or 3 days from now. Unless I flake out on my responsibilities, then it will be sooner, so it'll probably be sooner...
Best explanation I've seen of what an ERV is and does.
Great demo, i'd love to see a video with smoke passing through the box to show the air paths.
The best video I've seen to explain ERV. Congrats
This is amazing! Thank you so much for the explanation! I think it’s the best video on RUclips regarding the topic
Well done video. Clear explanations that a lay person can understand❤
Ryan, Excellent explanation of ERVs and HRVs
This video as really good at explaining ERVs. My HVACR class stumbled across you video of the psychrometric chart and it was very informative. I have copied this link and shared it with my instructor because I feel like our class will benefit from this training as well. Thank you for your videos and I look forward to viewing more of your content as needed.
One of the best explanation👍
Thank you♥️
Thank you for the video. I never came across ERVs in my 8 year long career as a facilities maintenance manager. I came across this technology when I moved to a cold country last year and really wanted to know how they worked.
Good job explaining main principle and types
Thank you for this video, excellent demonstration and explanation of the ERV, answered a lot of questions!
Im from Malaysia and this video help me understanding the system with full of information. Thank you from 2022
Great video and explanation... thank you! I am impressed with the efficiency of the wheel!
Okay, that's magic. Crazy! Thanks for posting this.
Thanks for explaining this topic and the demo, much appreciated.
Really enjoyed the presentation style, thanks 👍👍
Excellent explanation..congratulation brother
Well presented. Understood and now interested! Thanks!!!
Great explanation of how these work.
Great video and wonderfully clear explanations. Thanks for doing this.
Thanks! Great explanation. I was able to peak some design tips for my DIY ERV.
What a great presentation, well done.
Awesome video! Explained very well, both theory and example! Thanks!
That was VERY helpful to my understanding. Thank you!
very good. finally someone explained it well.
Great video! Thanks for making it easy to understand!
Thanks a lot for this Awesome Video. Got a really Nice Idea of how these systems work.
Very impressive vid. Keep up the quality. Will now have to research ERV's.
Best explanation on RUclips ❤❤❤
Thanks so much! You explained everything so well!
I always assumed HRVs are a waste of money. But I live in Monterey Ca where the climate is mild and perfect. But this video explained it great. I can now see them being beneficial in extreme temps with extreme humidity where fresh air is important.
lots of info, well presented, thanks!
perfect explanation.
Very good explained even for those with English as a second language! Thank you and greetings from Germany!
Do you need to keep it on all times or only when you need it
Fantastic explanation! Thank you very much!!
You explained it so good. Keet it up...
great demo and info!
Look, I just stumbled across this video. I'm a network engineer and understood 0% of how A/C, ventilation, HVAC, etc worked. But this guy did a GREAT job explaining this! (*me yelling across the house* "Hey honey, you want me to explain to you how an ERV keeps a building cool?!") That's right, I'm that kind of nerd who MUST share facts about things i'm excited to learn. 😋🤣
Yea this guys explination is top notch! I couldnt make heads or tails of why this type of system is used or its purpose... Now I want 1! lmao Oh and dont worry the nerds will inherit the earth! :P
Fantastic video guys; this will help with my power engineering exams :)
This was such a great video to understand ERV technology. The demo unit with the thermometers makes it that much better. Thanks so much!
Great explanations.Thank you sir👍
awesome video for explain two differences
glad someone explained this.
Very informative. Thank you
Thank you for your explanation.😊
Very good video!!! Thanks!!
Awesome video! ASHRAE recommends as much as outside air as possible for COVID. This is great technology to have to allow taking mostly outside air even when it’s hot or cold outside without impacting energy usage or performance.
Snake oil
Great video.
struggling to grasp until very end. very helpful
thanks for sharing the video
Fantastic explanantion
Very informative!
good explaination thank you
Great video! Thanks!
I have a question for you I just started working at a three story hotel I happen to go in the attic and found an ERV not running and hasn't been in awhile we have ducted energy on the first floor and Ptac units in all the rooms would it be wise to get the ERV running again to save energy cost or not ?
Thanks awesome video
Nice concept sir
Thank you!
dang didn't realize Richard Jefferson had a background in hvac
😂
It's Robbie Lawler bro
useful in the age of COVID when we want more fresh outside air coming in, and human exhalation going out of the building, without too much loss of heat or cooling
Blown away by how effective it works in that final demo. I'd expect to split the difference 50/50 on temperature at best, but it seems you're closer to 90% thermal energy rejection which is nuts.
For commercial systems, the minimum per most energy codes is 50% total recovery (sensible + latent). Most wheels are 65 to 75%, but some can be higher.
@@TECTubefilms Is there a difference between the efficiency of a wheel vs box style heat exchanger? Great video and demo btw 👍
Yes, per give area of space, a wheel generally trumps all other ERV types. For example, one of the manufacturers we use can run 30,000 CFM thru a wheel in a certain size cabinet. However, when they use that same exact cabinet chassis for a fixed plate ERV, they can only do a our 12,000 thru it.
Thank you so much video
thank you friend
Great video
Thanks
Thank you!!!
I'm thinking of building an small HRV, is there an advantage to the wheel type vs fixed fins? Leaning towards fixed fins and doing multiple cross flow cores or a single counter flow as it would be easier to build, but the wheel ones are also kinda intriguing.
The advantage of a wheel is that it has significantly higher heat transfer ability for a given size of cabinet. The disadvantage of a wheel is if you need AHRI certification for zero crossover (aka EATR).
Great vid
Thanks bro super helpful!
well done
I am having hall with entry 13x11 feet with length 67 feet and width 37 and height 14 feet please give your best advice for.air ventilation
Hello, I have a barndominium home that has spray foam insulation. The SPF is not allowing any fresh air into the home and it off gasses some during the summertime. My goal is to bring in fresh air to help with the off gassing. Which of the 2 devices would help me better, an ERV or whole house ventilator with dehumidifier? Also, does the ERV only work when the HVAC system is running? Thank you for your time.
The ERV will be less expensive to operate. The dehumidifier can remove moisture from both the indoor air and the incoming outside air. The ERV will only remove moisture from the incoming outside air.
Thaaank you
In a core-style residential unit like you showed, is it possible to turn an ERV into an HRV (or vice versa) simply by changing the core from one with a metal heat exchanger to a polymer heat exchanger (or vice versa)?
Yes, that is possible as long as your model has a drain. Lifebreath used to offer this option, but not sure if they still do.
Im thinking put stale intake for ERV in bathroom and above range. Could the fans be done away with? How many CFM per square ft? I saw another video it had U.S. divided into HRV or ERV. I live in ERV area but about 40 miles to HRV suggested area. Would it be beneficial to get a HRV
Yes, you can run bathroom air thru an ERV. We would not recommend you run air from the range. It has grease that you do not want to get on the ERV's heat exchanger. So use exhaust air from bathrooms and maybe a general area of the kitchen or a hallway. In this case you would completely eliminate the bath fans and just have a grill in the bathroom ceilings that duct to the ERV. Then have the ERV supply fresh air to the bedrooms and living room or have it bring the fresh air to the return duct for the furnace or main air handler.
From homes an ERV is almost always better than a HRV because it recovers moisture, as well. This keep moisture out in the summer and keeps it in during the winter. The reason there are maps to show not using ERVs in northern climates is because the ERV can develop frost on it from that moisture. Larger commercial ERVs have controls and/or heaters to avoid that, but that is not cost effective for small residential ERVs. So as you get to colder climates, you need to use a HRV for homes. The border for HRV vs ERV is specific to each manufacturer and their heat exchanger technology. So you need to look at the map specific to the model of ERV you are considering.
Thank you for your explanation, so the silca gel. Is it replaceable?
No, it does not need to be replaced. It is impregnated into the polymer. It doesn't wear off or anything like that.
What is the material of the fan in the demo unit? Is it a metal sheet?
And when we turn it on, the motor on both ends are the one pulling the air making the middle turbine moves by itself?
(Wanting to make one for the house) please help :)
No, it is not metal. The heat transfer wheel is a polymer impregnated with silica gel desiccant to allow moisture transfer, as well as heat. This type of ERV is not cost effective for small systems less than about 1,500 CFM. Residential only needs 60 to 120 CFM of outside air so in those applications we use entahlpy cores for heat transfer instead.
The two fans are to move air in and out of a building... you are exchanging heat and moisture between them. They do not make the heat transfer wheel (what you called a turbine) move. That is moved with a fractional hp motor and a polymer belt.
6:47 - if you want to learn the difference between HRV and ERV and how that works
What should the house exterior intake cover look like? We have a 8"x 8" bug screen with louvred flaps, but someone pointed out that it should be a boot cover, so that the outside air coming in is not impeded by the closed louvre flaps. Does it matter? Thank you, great video!
If the flaps are closed when the ERV is running then yes it matters.
I finally understand it!
In the UK we have humid winters, where ventilation is key to keeping the inside of homes warm and dry. Many people are talking about positive input ventilation (opposite of extractor fan just pumping fresh air into a central place to be blown through gaps of the building).. This increases heating cost as many units have a 500w duct heater to warm up the incoming air stream (~10c to -2c typically) and even then people complain of cold drafts from the unit.. I wonder if an HRV would help benefit.
Use the damp but warm exhaust from bathroom to preheat the incoming air somewhat..
Yes, you can run the bathroom exhaust through an HRV to reclaim the heat and transfer it to the incoming ventilation air to pre-heat that air less expensively.
Do not use an ERV in your application since that will also reclaim the moisture from the bathroom exhaust which it sounds like you do not want.
Great/fantastic/excellent video, love the plexiglass. I am looking for a similar system, but where the air exchanger could be bypass in spring & fall (hot days & cool night & since air is so cool at night, there would be no need to have the AC on). Am I missing something here? I can’t seem to find a system that does that.
Yes, most commercial ERVs have a bypass around the heat exchanger for "economizer days," since this is required now by IECC and most other energy codes.
I love the ERV demo unit, makes it simple to see during the summer months how the temp exchange works. I wonder if you have made a video with this reversed, showing the intake/exhaust during winter month where cold air is being introduced to the inside? I recently built an air tight house and do not have any type of ventilation system installed, hence it's drawing from the windows and doors creating a vapor in the cracks. I also have humidity levels that are running between 60-70% showing on my thermostat, btw I live in Alabama. I'm thinking I need an ERV to help bring in fresh air to balance things. Will this also help to lower my humidity level?
No, we did not make a winter video. However, it would do the same thing as the demo in this video. Just move the labels around. Instead of the warm air being labelled as "outside air," it would be "return air."
An ERV will only help with indoor humidity issues if the humidity is being caused by outside air coming in. When the ERV brings in the outside air in the summer, it transfers the heat and the moisture to the exiting exhaust air so it does not come back in.
However, if the source of your high humidity is something inside the house, then an ERV will make the problem worse since it will transfer the humidity from the return air back into the supply air.
So the first question with any humidity issue is "what is the source of the moisture?"
There are lots of things you can do to deal with high indoor humidity. This would be an abbreviated list from best to worst (the list changes though based on WHY you have high humidity).
1) eliminate moisture sources (put caps on sump and ejector pits, run bath fan when showering, etc)
2) Right-size the A/C. 99% of all system are oversized and more than half are grossly oversized. The smaller the A/C capacity, the longer the run cycle, and hence the better the dehumidification
3) Multi-stage A/C. This also keeps the system running and the evaporator dehumidifying
4) Lower blower speed for regular A/C mode
5) On demand dehumidification using the A/C and lowering the blower speed even lower than regular A/C mode
6) On demand dehumidification using the A/C but not lowering blower speed further because the system is too basic to do that
7) Slightly larger evaporator coil with more surface area
8) dehumidifier
You should note that some of the decisions above affect other stuff so should not be modified without research. For example, you may lower blower speed to dehumidify better but then realize you have a crappy duct system and can no longer get enough air to certain rooms.
Is there a measurement of how much energy is "lost" in this process? I realize that something can be derived based on that demo with the thermometers I am just curious if there have been papers/studies published on these.
Yes, but what do you mean by "lost?" Are you trying to figure out how much fan energy is being used to move this air? If that is the case, most selection software tools will tell you this kWh. Or are you trying to figure out how much heat is not being transferred that could be? If this is the case, then that is represented in the AHRI rated "effectiveness" percentage. Or are your trying to figure out how much leakage goes around the wheel on accident? This is represented by AHRI's measurements of OACF and EATR.
In summer, hot moisture air is sucked from outside, and this hot energy is transferred to heat exchanger, there by the hot air losing it's energy to heat exchanger and converts to cold air which is then pushed inside the building space...and vice versa in winter...is it right?..pls confirm.
yes basically
@@TECTubefilms Thank You for confirming
i’m replacing the capacitor on the fan, after the erv has been inactive for a couple years. there is some corrosion too. the fan spins, but it is like a bike wheel where there is contact with a brake pad, rather than a smooth spin that keeps going after released. how easily should the fan spin?
(oh, this is when i try to spin it by my fingers with the unit unplugged. i haven’t connected the capacitor yet)
It might be a "sweeper" that is slowing it down. That is a little brush like you have under your exterior doors. It is there to reduce inadvertent transfer. But in any case, you need to figure out what is slowing the wheel down when you spin it by hand and then decide if that is supposed to be there or not.
Nice!!
Would you say the ERV runs 24/7 in a residential application? My load calcs are calling for 84cfm so we assume that's constant.
If not too complex for your controls scheme, we would suggest running it when the home is occupied. Many smart thermostats can handle that. Or if not, you can at least tie the ERV to run off the EAC terminals of the furnace so it is engaged when the main fan is engaged... and then program your fan to run constant during occupied hours and intermittent during unoccupied.
Very good video, thanks. Does air flow through the wheel style heat exchanger (enthalpy wheel?) or across it? Are they available to diy'ers anywhere?
The air flows through it
Not sure how to answer your question about installing one yourself. You would need knowledge of HVAC design/sizing, sheetmetal working, and electrical wiring, and in some states/municipalities licenses to do work in those trades. Plus the smallest enthalpy wheels on the market are too large for homes. Residential applications would us the enthalpy core style.
Very good demonstration. How are the heat molecules separated by that spinning wheel?
No molecules of the air are separated. The air molecules pass straight through the wheel. In regards to the heat... heat always moves from hot thing to cold thing, so if the air is warmer than the wheel, then the air heats the wheel. Then the wheel spins to the other airstream where the wheel is not the warm thing so it transfers its heat to that cooler airstream.
Just noticed your name. LOL
Great video! What happens if its warm inside the house and you want to have the cold air outside to cool your house. That is the scenario in tropical countries where at night time it is usually colder outside than inside. Can I still pump in fresh air at the same time make inside the house cooler?
That scenario occurs frequently in commercial buildings so the units include an automated bypass which allows air to run thru the ERV fans and duct without going thru the actual heat exchanger. This is in place of the economizer that most standard commercial HVAC air handlers have. Small residential ERVs do not typically have a bypass, just like residential HVAC systems do not have economizers systems. The first cost is too high in residential for the energy cost benefit.
a mixing box would be perfect for residential applications. It brings in cooler dryer air from the outside and lowers the energy load on your cooling system .
Excellent video! Studying for an architecture registration exam, this is a really great illustration of something we usually only see in diagram form. Thank you for the thorough explanation!
Great 👌👌👍👍
Now I'm clear on how Erv works. Previously I got a lot of confusion on erv's
AMNJIRI
This is an absolutely excellent video explanation. Close-ups, hands on, shows what's happening.
He mentioned an exhaust duct "from FURNACE to HRV, then vented outside" at 5:55. Is this true, or was this duct pulling exhaust from bathroom? I'm trying to understand how to tie into existing HVAC ducting.
Yes, in this particular ducting scenario (and there is more than one way to duct it), the HRV pulls air from the furnace return and exhausts it outside. It then pulls air from the outside and replaces it in that return duct. This is the easiest way to duct it, but it also doesn't save any energy. The best way... as you hinted at... would be to pull air from the bathroom instead of using a bath fan and run that thru the HRV instead of pulling return air. This is air you planned to throw away anyway so may as well reclaim energy from it.
@@TECTubefilms Ok interesting. Thank you. I'm less worried about energy, more worried about excessive redundant systems, ducting, and wall penetrations (bath fans, HRV, kitchen fans, makeup air, furnace, dryer ducts, etc).
Do they make enthalpy core boxes (without the HRV blowers) that can duct straight to the air handler using its central fan? To consolidate some of these duplications? Which vents can be combined?
I don't understand why we ditch the high CFM flow rates and high MERV filtration of an air handler for these tasks, and instead use these dinky little 100cfm central exchangers. In full redundancy no less.
@@slipperyslope3912 Pretty much the ONLY reason to install a HRV is to save energy. If you don't need/want the energy savings and just want fresh air, then there are several methods to duct outside air into the HVAC system without the expense of a HRV.
@@slipperyslope3912 No, we have never seen a residential size HRV without a fan. Just ducting it into the air handler would not work. The pressure drop of the HRV heat exchanger and filters is so high, that the air handler will just draw all of its air from the return duct and none from the HRV duct.
@@slipperyslope3912 You do not lose the MERV filtration with a HRV ducted into an air handler. The outside air coming thru the HRV is ducted into the return of the air handler upstream of the air handler's filter.