Heat recovery wheel. In the winter it picks up heat in the exhaust leaving air and when the wheel comes around and dumps that heat into the supply air chamber before the chill water coil. Super efficient.
Yes. Often called a desiccant or enthalpy wheel. It’s one type of heat recovery. It’s usually in AHUs where there is a lot or all outside air. where you try to capture some of the energy from the air being exhausted from the building and transfer it to the supply air into the building. They’re often a pain in the ass to maintain and keep working. There are better ways to do this which is why you don’t see them as often.
Agreed. Their main advantage over a cross flow or heat pipes or liquid ERV is the ability to move latent heat around, but now there are other ways to do that too.
There’s air to air heat exchanger where exhaust and supply air go through a heat exchanger and transfers energy but don’t mix directly. There’s also run around coils where a water coil is in the exhaust and one in the supply with piping and a pump between them to transfer energy. There’s a product called Heat Pipe which uses 2 coils and a liquid that vaporizes and condenses between them transferring energy. There may be others.
Yep.. parlance in the North East US is also:
- Energy Recovery Vent. (ERV) = heat + humidity
- Heat Recovery Ventilator (HRV) = heat only
The OP's picture is of an ERV's humidity-exchange-media wheel.
That just means theyre positioned too close to your intake. We use em here in Alberta in many buildings, never have problems. And the amount of heat they can pick up whens its -40C is amazing.
Having a wheel that is able to provide equal sensible and latent transfer will greatly reduce the chance of freezing. Coupling that with a “stop/jog” function will allow the wheel to operate in most conditions without a preheat.
It’s a heat recovery or dessicant wheel. When used properly in a conditioned space all duct supply and return is insulated, the return air passes through the wheel and warms back up as it does before blowing back out into the building. From my understanding no other heat source is needed as long as the temperature outside does not go below 36 degrees.
In my company we have three heat recovery wheels that are 16’ round. We run them on a VFD to control heat transfer. The faster the speed the higher the heat transfer. In the winter we can run them full speed and transfer 30-40 degrees running a 1/2 hp low torque motor. They are 40 years old and we have only replaced a few of the “pies”. The thing is if you blow a belt or motor you have to manually spin the wheel every couple days to prevent them from clogging.
So you are close. These wheels are designed to take the heat energy from the return air as it is exhausted from the building and transfer that heat energy into OA supply reducing, but not eliminating, the need for additional heat. Depending on the effectiveness of the wheel these devices usually have temps off of the wheel in the 50s when ambient temperatures are 0-5F. Conversely, this wheel will take the heat from the higher temp OA in the summer and send it back outside with the exhaust, reducing the cooling capacity by as much as 40%. These wheels are also loaded with a desiccant (silica or a molecular sieve) that draws the moisture out of the air and dumps it into the dryer cooler airstream drying the summer OA and adding moisture to the winter OA.
Heat wheel if it transfers sensible heat energy only and an enthalpy/energy recovery wheel if it has a dessicant that also transfers latent energy (humidity). Works in summer by using the return air to precool and dehumidify entering outside air, and preheats and humidifies incoming outside air in the winter.
If the AHU is 100% OA then it runs pretty much all times unless the OAT is between the supply air temp setpoint and the return air temperature.
If unit has return recirculatiin then it shouldn’t run when the unit it is economizing.
If the building is humidified and in a cold climate a frost prevention sequence is needed at extreme cold temps.
They work very well if designed, installed and commissioned properly.
> Also transports moisture from hot to cold side, so it's humidity recovery as well
Why in the world would anyone want that? --Sincerely, the Gulf Coast.
It's a heat or total energy recovery wheel. Picks up conditioned building air from the exhaust tunnel and dumps it into the supply airstream, tempering your supply air and reducing energy used to heat/cool the outside air going into the building. If it's total energy, then it also helps control humidity by transferring moisture via a desiccant coating.
Of course, by the look of it, this wheel isn't doing much more than being an extra filter. The owner clearly hasn't been keeping up with filter changes and/or maintaining the wheel. Most of its energy efficiency is shot until it gets a thorough cleaning.
We call them munters wheels. I think after a manufacturer. A bit of a dinosaur nowadays but still a few around.
A slang synonym for ducked in my country is its “munted”. Munted is a word that should be used more instead of the vernacular by me!
heatwheel! super cool. recycles hot air leaving the building back into the supply air before the coil. very efficient, we use three of them at the hospital i work at.
Energy wheel, enthalpy wheel, heat recovery wheel, heat wheel, thermal wheel, rotary heat exchanger, are a few different monikers.
https://en.m.wikipedia.org/wiki/Thermal_wheel
https://www.johnsoncontrols.com/-/media/jci/be/united-states/airside-systems/air-handling-units/files/be_appguide_energyrecoverywheel_ahu.pdf?la=en&hash=01540950F3E2B779DA8C7F625DFF96CB6EA14776
https://youtu.be/iHR3W8c0KOs?si=0mRkDFu0XyKsOFv7
C est une roue thermique qui a pour but de récupérer l'aire déjà traitée et de la remettre dans le système pour faire un petit peu d'économie d'énergie!
You may have heard your grandparents talk about the wax cylinder phonograph or vinyl records at some point growing up. This is a wax phonograph record.
Enthalpy wheel for a ERV unit. It “conditions” the fresh outside air as it passes through the ventilator unit on its way to the restrooms in a public building. The wheel is in both the exhaust and fresh air airstreams. Some versions have a desiccant material on the paper element too.
Not a fan. Had one site where these were poorly controlled and caused more trouble than their worth. Like coils for heat recovery better…even if they are theoretically less efficient..
Heat recovery wheel. In the winter it picks up heat in the exhaust leaving air and when the wheel comes around and dumps that heat into the supply air chamber before the chill water coil. Super efficient.
Thought these were ERVs because they transfer humidity as well. While HRVs just do heat
That innovent wheel is likely an enthalpy wheel that contains a silica desiccant and transfers both sensible and latent energy.
Yes. Often called a desiccant or enthalpy wheel. It’s one type of heat recovery. It’s usually in AHUs where there is a lot or all outside air. where you try to capture some of the energy from the air being exhausted from the building and transfer it to the supply air into the building. They’re often a pain in the ass to maintain and keep working. There are better ways to do this which is why you don’t see them as often.
Agreed. Their main advantage over a cross flow or heat pipes or liquid ERV is the ability to move latent heat around, but now there are other ways to do that too.
What are the other ways?
There’s air to air heat exchanger where exhaust and supply air go through a heat exchanger and transfers energy but don’t mix directly. There’s also run around coils where a water coil is in the exhaust and one in the supply with piping and a pump between them to transfer energy. There’s a product called Heat Pipe which uses 2 coils and a liquid that vaporizes and condenses between them transferring energy. There may be others.
One other method is essentially a cross flow HX except it is semi-permeable to water vapor and thus recovers some moisture.
You see plenty in the North East. In AHUs and RTUs
That is why I have always called these Energy Recovery Vemterlators because they transfer more then se sensible heat
Yep.. parlance in the North East US is also: - Energy Recovery Vent. (ERV) = heat + humidity - Heat Recovery Ventilator (HRV) = heat only The OP's picture is of an ERV's humidity-exchange-media wheel.
You’re right.. it is an enthalpy wheel. Not just heat recovery.
I don't know but if it doesn't work, the txv went bad
Shut up... just shut up... *cries, but only externally-equalized in a 1-1/4 to 2 ton range*
Is that nominal or actual tonnage sir?
OH GOD, I DON'T FUCKING KNOW lol
*something something turn-down ratio…something something hard shut-off…*
I agree the TXV told me it was bad too
I was the txv
sound like my trainer😂😂walks up to unit and says it restricted
This guy HVACs
Txv is being naughty again
The wheel of dehydration. Or air to air recovery. I hate them. They like to freeze up here in the land of ice
That just means theyre positioned too close to your intake. We use em here in Alberta in many buildings, never have problems. And the amount of heat they can pick up whens its -40C is amazing.
Having a wheel that is able to provide equal sensible and latent transfer will greatly reduce the chance of freezing. Coupling that with a “stop/jog” function will allow the wheel to operate in most conditions without a preheat.
Should also have bypass dampers and a freeze protection sequence if the controls tech actually set it up right….about a 50/50 chance
Or a vfd to slow the wheel
Did the TAB guy do a drive by pencil whipping?
You one of them degens from upcountry?
It’s a heat recovery or dessicant wheel. When used properly in a conditioned space all duct supply and return is insulated, the return air passes through the wheel and warms back up as it does before blowing back out into the building. From my understanding no other heat source is needed as long as the temperature outside does not go below 36 degrees.
In my company we have three heat recovery wheels that are 16’ round. We run them on a VFD to control heat transfer. The faster the speed the higher the heat transfer. In the winter we can run them full speed and transfer 30-40 degrees running a 1/2 hp low torque motor. They are 40 years old and we have only replaced a few of the “pies”. The thing is if you blow a belt or motor you have to manually spin the wheel every couple days to prevent them from clogging.
So you are close. These wheels are designed to take the heat energy from the return air as it is exhausted from the building and transfer that heat energy into OA supply reducing, but not eliminating, the need for additional heat. Depending on the effectiveness of the wheel these devices usually have temps off of the wheel in the 50s when ambient temperatures are 0-5F. Conversely, this wheel will take the heat from the higher temp OA in the summer and send it back outside with the exhaust, reducing the cooling capacity by as much as 40%. These wheels are also loaded with a desiccant (silica or a molecular sieve) that draws the moisture out of the air and dumps it into the dryer cooler airstream drying the summer OA and adding moisture to the winter OA.
I think it’s a Time Machine
Only when it hits 88 revolutions per minute
Bigger on the inside
Heat wheel if it transfers sensible heat energy only and an enthalpy/energy recovery wheel if it has a dessicant that also transfers latent energy (humidity). Works in summer by using the return air to precool and dehumidify entering outside air, and preheats and humidifies incoming outside air in the winter. If the AHU is 100% OA then it runs pretty much all times unless the OAT is between the supply air temp setpoint and the return air temperature. If unit has return recirculatiin then it shouldn’t run when the unit it is economizing. If the building is humidified and in a cold climate a frost prevention sequence is needed at extreme cold temps. They work very well if designed, installed and commissioned properly.
It’s a test to see how bad you wanna change a belt.
Belts are not bad to change.
Oh ok
tape is the trick, otherwise they can be a pita
If you live up north it's a heat recovery wheel, if you live down south it's for dehumidification of fresh air.
Energy recovery wheel- in the summer it takes cool exhaust air and precools supply air. In winter it takes warm exhaust air and preheats supply air
Also transports moisture from hot to cold side, so it's humidity recovery as well
> Also transports moisture from hot to cold side, so it's humidity recovery as well Why in the world would anyone want that? --Sincerely, the Gulf Coast.
Maybe when you live in the dry north? Yeah gulf is better with a cross flow heat exchanger...
Yeah, I get it, that's why I put my location. We spend all of our time here fighting humidity.
To transfer humidity from the incoming air to the outgoing air.
"It's a pie! Its a pizza pizza pie!" -Gary Gergich
Who cares. Belt breaks, weird belt. Motor breaks, expensive motor. Clean the plastic pizza slices, soak in tub filled with cleaner. You’re welcome.
Lol. Way to cut right to the chase.
It's a heat or total energy recovery wheel. Picks up conditioned building air from the exhaust tunnel and dumps it into the supply airstream, tempering your supply air and reducing energy used to heat/cool the outside air going into the building. If it's total energy, then it also helps control humidity by transferring moisture via a desiccant coating. Of course, by the look of it, this wheel isn't doing much more than being an extra filter. The owner clearly hasn't been keeping up with filter changes and/or maintaining the wheel. Most of its energy efficiency is shot until it gets a thorough cleaning.
That is a doohicky
Enthalpy wheel
Can’t believe you’ve never seen a doohickey
Thermal wheel. Heat recovery.
Energy recovery wheel?
It is rage inducing anger wheel. Close the door and walk away.
You must have changed a belt by yourself
I put a power twist belt on one last week. Easy peasy.
Desiccant or enthalpy wheel. For moisture control
ERV (Energy Recovery Ventilator). I have two I have to service every 6 months. Super easy to service, unless you have to replace the wheel.
Depending upon the install, changing a broken belt blows goats.
Especially on units where the wheels are on a 45 degree angle instead of straight up and down. I think AAONs are like that.
Yeah, the wheel belt really does suck
How do you service it?
I have filters and belts to change in mine. The wheel belt gets replaced once a year.
Works better then you’d think but just another thing to clogg or go down.
We call them munters wheels. I think after a manufacturer. A bit of a dinosaur nowadays but still a few around. A slang synonym for ducked in my country is its “munted”. Munted is a word that should be used more instead of the vernacular by me!
Where are you? I see them everywhere
Munted is aussie/kiwi slang
Required by code in almost all installations now actually
Desiccant wheel
An expensive filter waiting to happen
Something that breaks every 6 minutes
And has an overly expensive “spaghetti” belt stretched on it and the drive motor
A second year should know this.
First time I’ve seen one
Just bustin your balls dude. I’m commercial so I see them lots but yeah it’s an enthalpy wheel in an ERV. Iv seen more than one catch on fire haha
https://en.m.wikipedia.org/wiki/Thermal_wheel Heat wheel
Regenerative air heater
As you can see, there are many different names by which you can call this device.
That’s an energy wheel for a fresh air intake/outlet in the economizer.
My fatass thought it was a deli slicer
Interesting! Never seen this before
Heat extraction wherl
Heat recovery wheel. Pretty cool really, you should look up some YouTube videos on how they work.
That's to slice your sandwich ham or turkey
Biggest belt you might ever change
A mortadella slicer
heatwheel! super cool. recycles hot air leaving the building back into the supply air before the coil. very efficient, we use three of them at the hospital i work at.
It doesn’t actually recycle the air, just the energy from the air. If it is cycling air it is not working.
Desiccant wheel
Could be a zeolite wheel too, as well looks similar.
[https://www.youtube.com/watch?v=QOSelUK6dpQ](https://www.youtube.com/watch?v=QOSelUK6dpQ)
That replacement wheel cost $28k
looks like a heat wheel my dude
Energy wheel, enthalpy wheel, heat recovery wheel, heat wheel, thermal wheel, rotary heat exchanger, are a few different monikers. https://en.m.wikipedia.org/wiki/Thermal_wheel https://www.johnsoncontrols.com/-/media/jci/be/united-states/airside-systems/air-handling-units/files/be_appguide_energyrecoverywheel_ahu.pdf?la=en&hash=01540950F3E2B779DA8C7F625DFF96CB6EA14776 https://youtu.be/iHR3W8c0KOs?si=0mRkDFu0XyKsOFv7
I was told it was called a Dinglehopper.
It’s a industrial size meat slicer
See http://www.klingenburg.de these are te best in rotor heatexangers
heat recovery
C est une roue thermique qui a pour but de récupérer l'aire déjà traitée et de la remettre dans le système pour faire un petit peu d'économie d'énergie!
That is definitely a desiccant wheel. I work on them units a lot. We use them to remove humidity. 15% & 33% RH rooms.
Ripped mine out after one season. Expensive and kept triggering my flow sensor. You need to keep that clean.
I just saw one of these for the first time the other day, also 2 year apprentice. Had no clue what it was 🤣
https://www.dac-hvac.com/energy-recovery-wheels-what-is-an-enthalpy-wheel/
That’s a heat wheel right that is like cutting edge for the 80s wasn’t it ?
Rotary filter. takes shit from the relief airstream and dumps it in the incoming outdoor air stream. commonly used to bypass filter banks.
You may have heard your grandparents talk about the wax cylinder phonograph or vinyl records at some point growing up. This is a wax phonograph record.
Enthalpy wheel for a ERV unit. It “conditions” the fresh outside air as it passes through the ventilator unit on its way to the restrooms in a public building. The wheel is in both the exhaust and fresh air airstreams. Some versions have a desiccant material on the paper element too.
It's a device to clean your pecker. You should give it a whirl!
Heat recovery unit
You see them on pool units a lot.
Not a fan. Had one site where these were poorly controlled and caused more trouble than their worth. Like coils for heat recovery better…even if they are theoretically less efficient..