When using an ahu with mixed air it was mentioned to close return when high co2 is measured . Since the unit feeds multiple rooms where is the co2 measured to decide damper position ?
Service engineer from the Netherlands here. Great video and explaination. I have never seen exhaust units without filter. It is common to have inlet and exhaust filters here. No matter if there is a heating wheel.
I’m loving these videos. I’m a construction project manager for commercial buildings and your videos have helped me understand HVAC a lot better. Thank you!
I work on these AHU’s every day and in the uk at NHS hospitals we have 40 of them and also air curtains in theatres. Very interesting work although it’s only 10% of our job. This was a great video.
You're videos are better at explaining basic fundamentals than some the HVAC courses on Udemy. Best of all your content is "free". I have just joined a well know HVAC automation company and your videos are helping me out a lot.
Great Video! One correction I'd point out: When talking about the fans @ 5:50, the fan on the right is more commonly referred to as a plenum or plug fan. The EC motor isn't necessary always equipped on these types especially in larger AHUs as EC motors cap out at roughly 7.5 HP. Often these come with a standard 3 phase electric motors with VFDs for VAV applications. Perhaps a video on the several different types of AHU fan arrangements (fan wall, etc.) would be helpful and especially if it highlighted some of the control intricacies involved with each.
Was struggling a lot with comprehension and retention of these concepts with my online HVAC courses. This was so easy and well illustrated it solved all my problems. Thank you so much!
I am working in a company fabricating AHU’s but i was the one who’s fabricating the panels in a automation machine process which is it can punch/shear/bend in one system..its very nice thing to hear how this AHU’S work..
Hello, for the buildings that I’ve seen in nyc, hot water coils are always before the cooling coils. Hot water coil (pre heat) won’t freeze in the winter due to the water circulating and temperature. Reheats by the VAV boxed would serve to further heat the space as required. Other than that I found your video to be extremely informative. Thank you!
Another good tip. Depending on where your humidity sprays are, if you do not need them you might consider keeping the water in the trough but not powering the pump. I have seen where the humidity sprays are actually built under the cooling coil so when full if humidity drops it doesnt matter, it goes out the overflow like it should. A problem can occur, and I have seen it first hand, where if you shut off the pump and drain the tub under the coil you WILL carry over water into the ductwork. Air takes the easiest path it can, by taking the water out you have made that easiest path to be right under the coil, where the humidity is dripping down. So you have air moving quickly under a dripping chill water coil and depending on how the unit feeds, up or down, you could end up with water very far from where the unit actually is. It can really send people on wild goose chase to figure it out but its really simple, you have to either block it with leaving it full of water or find another way, plywood etc.
Usually I never comment on VEDIO but your VEDIO is so convincing that I never stop myself to say something about it. You’re doing a great job Man, Keep it up
You missed one detail, EACs (Electronic Air Cleaners), I know many larger systems don't always use them but when I worked in HVAC I did see many on med to large roof top and in building systems. We also installed a lot of EACs in residential units, much easier to clean those than the big ones. I have found it's sometimes easier to explain air as a variable density fluid than as a gas, especially w customers who don't get physics as well, some you can't explain anything to and you wanna toss them into a big fan. Intelligent customers are usually easier to deal with. Good vid, caused a few amusing flashbacks, one scary one, lightning storm suddenly over the roof top unit and I was inside switching out big filters, yeah, you don't wanna be inside an uninsulated metal box w lightning nearby, fastest to the roof access hatch I ever moved.
A few years ago, I used to help install them, many on building rooftops - as a duct fitters mate. I often got my hands burnt during hot summers, and even worse, got them stuck to the ducting during freezing cold winters!!... Thankfully though, I managed to avoid any lightning storms!! Lol!!
Great training video, the only issue I see here is the placement of the coils, heating coils are always in front of the chill water coil to protected them from cold temperatures drops.
Thanks for the vid, understanding hvac systems helps me feel more gratitude for the laborers that work on these systems to make buildings feel comfortable and normal.
ALL your videos are so helpful, and they are made to be really easy to understand. Really good use of 3D models (is it sketchup??? cannot imagine the amount of work you put into building these), along with real life examples. So blessed to have found you.
That was really interesting. Roughly what I figured but that wheel concept is new to me! Been brainstorming various ideas to build a air handler for my server room which I'll be enclosing soon and my goal is to also keep it as efficient as possible so this gives lot of ideas.
2:22 How Air Handling Units Work 2:00 Air Handling Unit 2:09 Compressor 2:15 Oil Seperator 2:22 Condenser 2:27 The master solenoid, filter dryer and thermostatic expension valve 2:45 Before Starting Checks: Oil > Valves > Power Supply. >Oil Level at compressor > Cooling Water Inlet - Outlet Valves to the condenser > Open the compressor outlet valve, condenser inlet valve, receiber outlet valve, filter drier inlet valve and outlet valves. > Check whether power supply to the compressor motor and blower > Ensure Compressor manual. 3:55 Starting: Valves Open compressor inlet valve half a turn > Start compressor > Open the compressor inlet valve slowly to fully open mode > Change compressor mode to AUTO > Check ampres, blower motors, temperatures 4:39 During Operation: Parameters > Oil level > Temperatures Suction and oil pressure, vibration, oil level, inlet, inlet outlet air temperatures at air handling unit 5:15 Stopping: Cut off > Shut Down >When air temperature reaches set value, thermostatic switch will cut off the compressor. When air temperature increases, the compressor will cut in. >Close the condenser liquid receiver outlet valve for Shut Down for long period. >Compressor stops due low pressure > Shut the refrigerant line valves. > Shut the condenser cooling water inlet and outlet valves > Switch off the power supply.
Well, this is amazing video. It shows almost everything possible. It is important to notice that when using plate heat exchangers, It is likely the filters on intake will be before heat exchanger, so heat exchanger can last longer. One can probably also combine heat plate exchanger with additional heat coil exchangers and some pumps to extract some extra heat. The coils will be also on opposite sides, to help by using cross flows.
Great video. Everyone's putting there's trade down. I install the ductwork and land and connect ahu's. Have done for 9 year's in hotels and hospitals in the uk. Never seen a fhu. Guess theres alot of dirty air getting pumped around 🙃
FAHU comprise of 100% cooled & dehumified fresh air to be supplied either directly inside the room or at the mixing box of ahu/fcu, while AHU comprise or supply & return air mix with percentage amount of fresh air come from outside air.
That depends on the scale of things. I work for a major university, for example, which has a central power/heating/cooling plant for the entire campus. Since a building might be a few miles away from the plant that generated the chilled water for cooling, the waste heat from the cooling units isn't readily available. That might be an extreme example, but it's probably often not feasible to route the waste heat back to the AHU.
Hello, is the activation of the heating and cooling coils automatic based on the inlet air temperature? Or can it be toggled manually? Appreciate a reply! Thanks!
Nice presentation ..Quick question- Why is the defrost preheat before the inlet filters? I presume to ensure filters wont be full of moisture etc? I have seen rotten and blocked preheat coils as they have had no protection from the elements. Typically this is LTHW heat exchanger fitted as a preheat.. Any thoughts appreciated...
Hello this Very lmportant to have HVAC but in the next video help us to give us different between FCU,Ahu, when it's work in cools, Hot, and dry seasons thank you
Correct me if I'm wrong, but I think I've figured it out. The order is: 1. Heating Coil ---> 2. Humidifier ---> 3. Cooling Coil In this order, the water can drain through the drainput of the cooling coil if it is necessary to raise the humidity. I think the humidifier should never be mounted in front of the fan, as this has a negative influence on the motor of the fan.
Hi thanks for your videos they are brilliant , appreciate your time and help me and others to understand more about hvac. Kindly I would like to learn about how to calculate extractor and air-in units and canopy in restaurants ,please. Again thanks for your time and help:)💐💐💐
Very good video! There are also other, more effective types of heat-exhangers in AHU's to capture the heat of the extracted air that are more ffective than the one with coils, but it's a very good example. Rotary heat exhangers as an example are very effective, but risk returning smells into the incoming air, but again, there are other variants still. Cheers on a good video!
On the hottest and coldest days of the year a good engineer will close the minimum air dampers as much as possible without closing them completely, to conserve energy during those few days. Its not recommended except in extreme situations though, and a run around can help with it as well as a preheat too. Some areas just have too high a minimum air rules. Try heating up -15 degree minimum air.. .. Its an important thing to provide minimum air but in my 30 years of experience in a large commercial and retail complex you just have to do it sometimes. Another thing I have had to do is close them during fires in the area so as not to suck in the smoke or chemicals. By rule you should never close them, in reality sometimes you have to make the choice to do it as its your job to run the plant safely and efficiently.
Awesome video. Anyone knows if there's an instrument to measure supply air pressure output at the AHU before it enters the main supply duct line? This is to know if the unit is producing enough "pressure thrust" especially for older units. Thanks
What do you think about high velocity micro duct systems. Often used for renovations where there isn’t much ceiling space or access. But what do you think about using the for residential new builds?
FAHU (Fresh Air handling Unit): It is used to circulate fresh air to the system. AHU (Air Handling Unit): It is used to recirculate the used air to the system again.
Can you explain the purpose of a Desiccant Dryer Unit that is sometimes connected to the outside air intake on some AHU’s? And why does it seem like the building EA is heated before the wheel then cooled again?
von Darkmoor | Sure, that is one place it could be... but I’m currently in a small residential building, and *AS WE ALL KNOW,* AHUs are generally not found there... :3
⚠️ *Found this video super useful?* Buy Paul a coffee to say thanks: ☕
PayPal: www.paypal.me/TheEngineerinMindset
Thankyou guesok
When using an ahu with mixed air it was mentioned to close return when high co2 is measured . Since the unit feeds multiple rooms where is the co2 measured to decide damper position ?
The
Great learning material
Please do a demonstration of how adiabatic coolers work in HVAC Systems. Thank you!
I’m a building mechanical engineer and I approve of this video. What a great and simple explanation
Service engineer from the Netherlands here. Great video and explaination. I have never seen exhaust units without filter. It is common to have inlet and exhaust filters here. No matter if there is a heating wheel.
Why filter the air going out?
I’m loving these videos. I’m a construction project manager for commercial buildings and your videos have helped me understand HVAC a lot better. Thank you!
I work on these AHU’s every day and in the uk at NHS hospitals we have 40 of them and also air curtains in theatres. Very interesting work although it’s only 10% of our job. This was a great video.
You're videos are better at explaining basic fundamentals than some the HVAC courses on Udemy. Best of all your content is "free". I have just joined a well know HVAC automation company and your videos are helping me out a lot.
Im a Diploma Engineer and Love working with BIM and now this HVAC also .. I love to learn by this innovative approach.
Thank you, really glad it's helping you
@@EngineeringMindset It really helps alot plz can you make for MEP also.
Not being rude, just curious. What's a diploma engineer?
@@s.n.9485 sure... diploma means polytechnic university or Technical college
@@memyadventures2730 cool. How did you get into BIM? It's something I've been wanting to do.
I'm gonna have to watch this at least 17 times.
David Delgado I’m doing electrics, I have to re read the same paragraph 200 times and still don’t get it
2 years later.. did you get it? I’m in low voltage controls now and am trying to learn as much as I can
Nicely explained. I'm a HVAC design engineer and approve this message.
I’m an HVAC DDC Technician and I also approve this message.
Bro, I'm new to hvac. I'm studying hvac. I need some help from you
Can you help
@@bakeermohamed5278 .
I thought that first part of the video was about Frash Air Handlers. There is a bit different beetwen them
I thank God i came across this channel. As a Junior Facilities Management professional, this will surely help me master my building services.
I'm only in secondary school and all of your content is so clear and intresting, thanks mate
Great Video! One correction I'd point out: When talking about the fans @ 5:50, the fan on the right is more commonly referred to as a plenum or plug fan. The EC motor isn't necessary always equipped on these types especially in larger AHUs as EC motors cap out at roughly 7.5 HP. Often these come with a standard 3 phase electric motors with VFDs for VAV applications. Perhaps a video on the several different types of AHU fan arrangements (fan wall, etc.) would be helpful and especially if it highlighted some of the control intricacies involved with each.
Was struggling a lot with comprehension and retention of these concepts with my online HVAC courses. This was so easy and well illustrated it solved all my problems. Thank you so much!
What online hvac courses where you taking if you don’t mind me asking? Did you have to pay for them?
I am working in a company fabricating AHU’s but i was the one who’s fabricating the panels in a automation machine process which is it can punch/shear/bend in one system..its very nice thing to hear how this AHU’S work..
Hello, for the buildings that I’ve seen in nyc, hot water coils are always before the cooling coils. Hot water coil (pre heat) won’t freeze in the winter due to the water circulating and temperature. Reheats by the VAV boxed would serve to further heat the space as required. Other than that I found your video to be extremely informative. Thank you!
Oh yes every AHU is different, tried to make a very generalized video for the basics
Good catch on the coils
I never hit the bell icon, but this youtube channel is just so good I just have to
Being an electro-mechanical engineer in construction, i will say your channel is amazing!
Another good tip. Depending on where your humidity sprays are, if you do not need them you might consider keeping the water in the trough but not powering the pump. I have seen where the humidity sprays are actually built under the cooling coil so when full if humidity drops it doesnt matter, it goes out the overflow like it should.
A problem can occur, and I have seen it first hand, where if you shut off the pump and drain the tub under the coil you WILL carry over water into the ductwork.
Air takes the easiest path it can, by taking the water out you have made that easiest path to be right under the coil, where the humidity is dripping down. So you have air moving quickly under a dripping chill water coil and depending on how the unit feeds, up or down, you could end up with water very far from where the unit actually is. It can really send people on wild goose chase to figure it out but its really simple, you have to either block it with leaving it full of water or find another way, plywood etc.
Usually I never comment on VEDIO but your VEDIO is so convincing that I never stop myself to say something about it. You’re doing a great job Man, Keep it up
Excellent videos
You missed one detail, EACs (Electronic Air Cleaners), I know many larger systems don't always use them but when I worked in HVAC I did see many on med to large roof top and in building systems. We also installed a lot of EACs in residential units, much easier to clean those than the big ones. I have found it's sometimes easier to explain air as a variable density fluid than as a gas, especially w customers who don't get physics as well, some you can't explain anything to and you wanna toss them into a big fan. Intelligent customers are usually easier to deal with. Good vid, caused a few amusing flashbacks, one scary one, lightning storm suddenly over the roof top unit and I was inside switching out big filters, yeah, you don't wanna be inside an uninsulated metal box w lightning nearby, fastest to the roof access hatch I ever moved.
A few years ago, I used to help install them, many on building rooftops - as a duct fitters mate. I often got my hands burnt during hot summers, and even worse, got them stuck to the ducting during freezing cold winters!!... Thankfully though, I managed to avoid any lightning storms!! Lol!!
Nicely explained
I’m a Mechanical Engineer by Trade and have done HVAC design for Years and I approve this message
Thanks!
Thank you, Tanner!
I love all this ,am not engineers or even work in this feel I just hungry for all knowledge
Great training video, the only issue I see here is the placement of the coils, heating coils are always in front of the chill water coil to protected them from cold temperatures drops.
I was watching and thought about 11:20 's design before it came up. Awesome that's a thing.
i am loving this series as the video goes on
The best channel i ever seen... and also the main thing i love about your presentation in video. its soo easy to understand even also for freshmen.
Super nice video... the sound is at proper level ....
Thanks for the vid, understanding hvac systems helps me feel more gratitude for the laborers that work on these systems to make buildings feel comfortable and normal.
It's not labourers that work on these systems but HVAC engineers and technicians. Ok
ALL your videos are so helpful, and they are made to be really easy to understand. Really good use of 3D models (is it sketchup??? cannot imagine the amount of work you put into building these), along with real life examples. So blessed to have found you.
This was a really great video. Thank you!
You have an amazing channel and love how you always get right into it. Thank God for RUclipsrs like you or I'd be fd.
Amazing thank you I'm new to the engineering department In a hospital. Very helpful
Really an engineering mindset video.
Thanks a lot.
I see some Camfil filters! Nice. We install and replace Camfil filters in air handlers. This is great info
Interesting video! I would like to see a follow up video about the duct work itself , different sizes, shapes , why they are metal ect.
Here you go ruclips.net/video/5y_VBiTiuAY/видео.html
All your videos are very helpful!! Thanks Paul!
That was really interesting. Roughly what I figured but that wheel concept is new to me! Been brainstorming various ideas to build a air handler for my server room which I'll be enclosing soon and my goal is to also keep it as efficient as possible so this gives lot of ideas.
2:22
How Air Handling Units Work
2:00 Air Handling Unit
2:09 Compressor
2:15 Oil Seperator
2:22 Condenser
2:27 The master solenoid, filter dryer and thermostatic expension valve
2:45 Before Starting Checks: Oil > Valves > Power Supply.
>Oil Level at compressor
> Cooling Water Inlet - Outlet Valves to the condenser
> Open the compressor outlet valve, condenser inlet valve, receiber outlet valve, filter drier inlet valve and outlet valves.
> Check whether power supply to the compressor motor and blower
> Ensure Compressor manual.
3:55 Starting: Valves
Open compressor inlet valve half a turn
> Start compressor
> Open the compressor inlet valve slowly to fully open mode
> Change compressor mode to AUTO
> Check ampres, blower motors, temperatures
4:39 During Operation: Parameters > Oil level > Temperatures
Suction and oil pressure, vibration, oil level, inlet, inlet outlet air temperatures at air handling unit
5:15 Stopping: Cut off > Shut Down
>When air temperature reaches set value, thermostatic switch will cut off the compressor. When air temperature increases, the compressor will cut in.
>Close the condenser liquid receiver outlet valve for Shut Down for long period.
>Compressor stops due low pressure
> Shut the refrigerant line valves.
> Shut the condenser cooling water inlet and outlet valves
> Switch off the power supply.
Seen our new pressure switch video? Link: ruclips.net/video/YG81w0HFXNc/видео.html
Nice video, I would prefer this video with captions to this 😀
Im maitenance worker at a hotel; and i been operating an AHU for almost like a year now without knowing what "AHU" means.
😂
😂@@pratikbhusal1
Best channel at the whole youtube
Well, this is amazing video. It shows almost everything possible.
It is important to notice that when using plate heat exchangers, It is likely the filters on intake will be before heat exchanger, so heat exchanger can last longer.
One can probably also combine heat plate exchanger with additional heat coil exchangers and some pumps to extract some extra heat. The coils will be also on opposite sides, to help by using cross flows.
All of your videos are very helpful, for me just bit slower. Please Thank you
Thank you for a really informative and well presented run down.
Great video. Everyone's putting there's trade down. I install the ductwork and land and connect ahu's. Have done for 9 year's in hotels and hospitals in the uk. Never seen a fhu. Guess theres alot of dirty air getting pumped around 🙃
So happy I found this channel! Cheers!
Chemical dehumidifier video would be great if you have time, thank you anyways!
FAHU comprise of 100% cooled & dehumified fresh air to be supplied either directly inside the room or at the mixing box of ahu/fcu, while AHU comprise or supply & return air mix with percentage amount of fresh air come from outside air.
THIS WAS AMAZING!!!! SO CLEAR! I MIGHT ACTUALLY PASS MY ARCHITECT REGISTRATION EXAM BECAUSE OF YOU!
This video is very helpful. Thank a lot
I mean to dehumidify the air you could use the pumped out warmth of the cooling unit to warm it up again, so it shouldn't cost much more energy
That depends on the scale of things. I work for a major university, for example, which has a central power/heating/cooling plant for the entire campus. Since a building might be a few miles away from the plant that generated the chilled water for cooling, the waste heat from the cooling units isn't readily available.
That might be an extreme example, but it's probably often not feasible to route the waste heat back to the AHU.
This helped me a lot. Thank you for your effort.
I HV seen you somewhere Bhai.
Very well explained brother. Thank you so much for your effort.
very informative..........thanks dude
Hello, is the activation of the heating and cooling coils automatic based on the inlet air temperature? Or can it be toggled manually? Appreciate a reply! Thanks!
Beautiful video Sir🤩🤩🤩🤩😍😍😍😍😍😍
Glad you enjoyed it
great explanation, now I know... thank you very much
these videos are too good
Hi your training video is great you should do a video on VAVs and DDC controls keep up the good work
Nice presentation ..Quick question- Why is the defrost preheat before the inlet filters? I presume to ensure filters wont be full of moisture etc? I have seen rotten and blocked preheat coils as they have had no protection from the elements. Typically this is LTHW heat exchanger fitted as a preheat.. Any thoughts appreciated...
Hello this Very lmportant to have HVAC but in the next video help us to give us different between FCU,Ahu, when it's work in cools, Hot, and dry seasons thank you
Really love the incorporation of the soft jazz music 💯
Next level teaching
Thank you! Very useful video.
Really helpful. Thanks 🙏
Awesome video 👌
Correct me if I'm wrong, but I think I've figured it out. The order is:
1. Heating Coil
---> 2. Humidifier ---> 3. Cooling Coil
In this order, the water can drain through the drainput of the cooling coil if it is necessary to raise the humidity. I think the humidifier should never be mounted in front of the fan, as this has a negative influence on the motor of the fan.
Hi thanks for your videos they are brilliant , appreciate your time and help me and others to understand more about hvac.
Kindly I would like to learn about how to calculate extractor and air-in units and canopy in restaurants ,please.
Again thanks for your time and help:)💐💐💐
Hi have you checked out our ductwork video?
Nice vid, really clear and good points.
Very good video! There are also other, more effective types of heat-exhangers in AHU's to capture the heat of the extracted air that are more ffective than the one with coils, but it's a very good example. Rotary heat exhangers as an example are very effective, but risk returning smells into the incoming air, but again, there are other variants still.
Cheers on a good video!
Awesome video
Awesome explanation
This channel convinces me I definitely ate paint chips a a child. Too esoteric for me.
Don’t under estimate your intelligence, it helps to have been inside a unit and compare it to a graphic like this video.
@@dodecoates7346 thank you for the beautiful encouragement I really appreciate it even though you don't have to do it
@@daviddelgado475 no problem glad to do it
Very interesting . I wanted to know how AHU work in case of fire in the building ?
Thanks a lot for the helpful information and contents
Great Video
thank you so much for this video as it has been immensely useful and I am definitely watching more!
Please make a video about adiabatic process of HVAC system.
On the hottest and coldest days of the year a good engineer will close the minimum air dampers as much as possible without closing them completely, to conserve energy during those few days. Its not recommended except in extreme situations though, and a run around can help with it as well as a preheat too. Some areas just have too high a minimum air rules. Try heating up -15 degree minimum air.. .. Its an important thing to provide minimum air but in my 30 years of experience in a large commercial and retail complex you just have to do it sometimes.
Another thing I have had to do is close them during fires in the area so as not to suck in the smoke or chemicals.
By rule you should never close them, in reality sometimes you have to make the choice to do it as its your job to run the plant safely and efficiently.
Nice video sir 👍👍👍👍
Awesome video. Anyone knows if there's an instrument to measure supply air pressure output at the AHU before it enters the main supply duct line? This is to know if the unit is producing enough "pressure thrust" especially for older units. Thanks
Great tutorial, thanks for sharing
Please prepare a video on VRF/VRV system in detail, I will be greatly thankful
New VRF unit video here:➡️ ruclips.net/video/4i1XgcP1tmw/видео.html
Thank you very much dear sir.....
wow this is amazing !
It helps a lot thanks
Good job, thank you !!!
excellent video to understand.
What do you think about high velocity micro duct systems. Often used for renovations where there isn’t much ceiling space or access. But what do you think about using the for residential new builds?
FAHU (Fresh Air handling Unit): It is used to circulate fresh air to the system.
AHU (Air Handling Unit): It is used to recirculate the used air to the system again.
I do not kbow! Thank you for very intresting video! =)
Can you explain the purpose of a Desiccant Dryer Unit that is sometimes connected to the outside air intake on some AHU’s? And why does it seem like the building EA is heated before the wheel then cooled again?
What about face and bypass? Dual path? Multi zones? Good video anyway
Yes, maybe in a future video
That run around system for heat recovery can also be used in place of that electric pre-heat coil for the 100% OSA/100%RA-EXH systems.
1:08 | “AHUs are found either in the basement, on the roof, or on a floor of a building.”
*WHERE ELSE WOULD THEY BE*
In the safe space
Lyle | *HMMMmmm...*
Hudson Baker | I think that’s still a floor.
BEHIND YOU!!!!
von Darkmoor | Sure, that is one place it could be... but I’m currently in a small residential building, and *AS WE ALL KNOW,* AHUs are generally not found there... :3
Thank you so much🙏
Very good video, but I think you missed some temp sensors and frost sensor
Great video. Thanks!
Why I was recommended this I have no idea but super interesting
good video ~~tkx