So much of this was over my head but I was able to follow the overall concept. Given the fact I’m not even close to being called an engineer, you really lived up to your channel name. Excellent job of explaining complex issues, in an understandable way, without making me feel condescended to, thank you.
Bro I wish I saw this a few years ago when I started as an hvac engineer. You described something that took me months to get the full picture from the lax training at my company.
Just enjoyed your video for the first time today on its 4th anniversary. 690,606 views is a testament to how well delivered the material was in your video. As I find myself less and less confident in contractors of late, it is appreciated that you are providing content to empower viewers with knowledge that might have felt out of reach initially. Thanks again and many well wishes for continued success for you and your channel.
This was a fantastically simple overview of the engineering process needed to accurately specify a ducting system. Here in the States among contractors, the most common method for duct sizing in residential is the "friction loss per 100 ft." method wherein we calculate the total equivalent length for the longest runs (both supply and return) and size everything based on getting the appropriate amount of air to these runs and balancing the rest with dampers. Really wish there was an instructional video on this process (or even the equal friction method) in Imperial units out in UA-cam. Thanks for providing such fantastic resources for the industry.
Yeah this is pretty cool. Im a sheet metal apprentice, specializing in ductwork for commercial jobs. Interesting to see how the ductwork I make is designed and such. Great video!
I’m the same here just helped commission a job and was curious how they came up with air flow rates on the drawing and it’s pretty insane how much goes into it just for us to come along and make they’re job more fun 😂
I got my Ac system installation almost a year ago, it smells very bad and when I turn it on it smells like dump wet bathroom. In order to get it to stop smelling I have to get the temperature down to 24, but then it's too cold😢 does anyone know if they have done for me a cowboy job, as I have spent a lot of money
@@victory6904 24 degree fahrenheit? Or Celsius. Either way you could have someone come potentially clean it, install uv lights or some sort of duct cleaning system. It sounds like it might be mildew caused by not properly insulated duct so it could be sweating and building up water that's smells gross. Could be improper drainage. Hard to diagnose something on the Internet just get a professional to look at it
As someone who has been doin HVAC design for a while, this is very helpful if you’re trying to understand the theory and calculations for the design. But in the real world, no one is going to build ductwork like yours because everyone is cheap and prefers round taps and tee junctions.
Great video, it's important to also note that's another driving factor for the mass flow rate is the fresh Air supply which is higher than your cooling or heating loads would override your video size
Amazing video, thank you. I noticed in the video (14.39) you are inputting the data into the interpellation website. that you input in Q11 value 0.14. Should it had been 0.15? (LOL) Its just me and no big deal. It kept me on my toes...so very helpful on your part. Love the videos.....THANK YOU
Great video this, can you also do a video on "calculating the cooling and heating loads using psychrometric charts" for HVAC systems? Really appreciate it if you can
In calculating the pressure loss in the Tee Fitting, why do you only apply the dynamic loss formula in the straight direction and not in the bend too? For the bend you've only used the co-efficient of 0.3645 (15:45) and not used this in the dynamic loss equation, like you did after getting the co-efficient of 0.143 in the straight section (14:45).
Error At minute 15:45 - for the H Tee branch G-I only the value of the loss coefficient was tabulated as 0.36 instead it should have been the value obtained when calculating the fitting loss as was done for the straight duct GJ which gave 0.93 Pa. some clarification needed here?
Great video, For the Tee 'H'at 15:45, is it not the bend coeff' 0.3645 taken from table using vel and area ratios, then using formula to find out the pr loss ?, It says straight from table, the coef 0.3645 as pr loss in Pa. Pls clarify. Thanks.
Hi At 15:42 you calculated the C0 from the table and interbolation, and you forgot to calculate the P loss in the bend direction using the formula (P=C0*density*velocity^2/2) ,you have put it into the table directly . Plz notice that and if i'm Wrong tell us the Right plz.
Thank you for this video, its very helpful. Do you have any thoughts on having the last take-off come off the end of the trunk (as you have designed in your example)? Most conventional advice says to take it off the side and cap the end to allow the trunk to pressurize.
Sohrab: Ques 4:- Coefficient of pressure values of fittings like Reducer=0.25 Elbow=0.27 It will varies or fixed according to CFM Ques 1:- During calculating static pressure only critical path will be taken or not ? Ques 3:- In formula (F×L)/100 F= friction factor or friction head loss Ques 2:- we will calculate all the VCD OR only critical path?
You're paying for them either way. Cooling load is usually electricity, but because of the COP of the unit the actual amount of electricity used may be many times less than that calculated load, but you also have to consider the fans and the water used if it uses evaporative cooling or humidifiers. The heat load is usually natural gas here in Burgerland so you might end up using 5% or so more natural gas worth of heat than the load calculated due to the slightly inefficient nature of burning fuel (you can't breath the exhaust so the heat has to be transferred into usable inside air or another working fluid such as water in a hydronics system). Condensing heaters have come a long way at getting us up to 96% or more efficiency. In any case this is usually still cheaper because natural gas is many times cheaper than electricity is on a raw heating value BTU/hr (kWh) basis.
Nice and clear video, well done. Do you have any videos on how to calculate proper condenser and evaporater size/capacity in relation to compressor size/capacity on custom AC units ? If not please consider making one. Thanks
Great video, I just have one question. When determining the mass flow rate, in the image it says to use delta T in terms of Kelvin but I believe you used your 8 degrees Celsius to get the mass flow rate for each room? Should we convert that into Kelvin?
Can anyone explain why the Bend Loss Coefficient is used directly as the Dynamic Pressure Loss (15:40) rather than doing the Equation again as shown in 14:53 ?
Loved the video - can you make one with Imperial measurements for your slower US brethren? :) You can say - oh just use feet vs... However if the video was done all the way through with measurements we'd likely use, it would be easier to follow.
The Engineering Mindset :- I have have not under stand Fitting example H : Outlet direction 2-Bend (Time 15:10 - 15:48). Calculated Velocity ratio and Area ratio, then based on that get coefficient 0.364 from bend table. My question is why don't we applied that coefficient value in pressure loss equation {pressure loss=coefficient x density x velocity Sq. / 2}. instead of that directly mention that vale 0.364 as fitting loss in Direction G-I. Anyone please help
How to calculate If air grills fix directly on the duct ? E.g: air volume is 10800 m3/h and 10 SAGs fix on the duct. The pressure drop thru SAG? Thank bro
Fantastic and excellently explained. Does anybody know of any online calculation software or any programme that can help with sizing ducted airconditioning units and FCU's with the correct size ductwork?
Fitting loss in G-I direction should not be 0.36. I guess, 0.36 is the Fitting Coefficient. So, the fitting loss in G-I direction should be 2.65. Please correct me if I'm wrong. Thank you.
Hi, Amazing video, really has helped me complete an assignment that I had no information on how to complete. However I'm still going to fail because you didn't calculate grilles. Also you stated that you would include the fitting tables you used in the video in the description, but it's not there and I have spend the last two hours looking for a god for saken fitting tables to no avail.
@@EngineeringMindset Aha! I see, in that case, thank you. Your videos are just so well put together and beautifully explained, you honestly really helped me out. Thank you for replying.
Out of curiosity, do you only need to bring fresh, conditioned air into the rooms? Is it not necessary to also suck out the stale air using a separate duct system?
can you also do a comparison of using one centralized hvac system versus mini-split units for the same size of a house having four bedroom and two floors. tks.
@ 2:14 delta_T = 8 [Centigrade] but formula calls for [Kelvins], Is there a mistake in the Calculations ? delta_T should be 8+273.15 Kelvins not 8 Kelvins. Thanks
Delta_T should be 8. It a temperature *difference* between supply and return temps. Let say the supply temperature is 17 C and the return is 25 C. That's 290 K and 298 K respectively. Difference still is 8.
I have two comments : First: pressure loss for Tee G-I (bend) is less than G-J (straight) How ? Second: we need link for the duct pressure loss chart thank you so much Great video about Duct Design
why is a fan selected based on only index run pressure loss , what about all other pressure loss in other branches ? fan need to pump air through the other branches right /? like pressure loss of AB+BC+DE+EF+EH+HL
you put *fitting loss=0.93Pa* in the table for G-J direction by equating: coeff.(0.143Pa) x density x velocity out^2 ÷ 2 but for G-I diection, you just put value of *coeff.(0.36Pa)* into the table. I didn't understand why didn't you applied fitting loss formula for G-I direction?
Question: Why are two story homes, fitted with 2 units, but not ducted to accommodate 'convection'? Heat going up, cold falling. Returns are on the same floors as ducts for each unit. WHY?
⚠️ *Found this video super useful?* Buy Paul a coffee to say thanks: ☕
PayPal: www.paypal.me/TheEngineerinMindset
Done ;-)
comment the photo of the Duct Pressure Loss Chart Please :(
@@JudgeFredd so 33
Could you do one about fabric ductwork?
So much of this was over my head but I was able to follow the overall concept. Given the fact I’m not even close to being called an engineer, you really lived up to your channel name. Excellent job of explaining complex issues, in an understandable way, without making me feel condescended to, thank you.
Yes I suffered many a nose bleed during this video
Bro I wish I saw this a few years ago when I started as an hvac engineer. You described something that took me months to get the full picture from the lax training at my company.
Just enjoyed your video for the first time today on its 4th anniversary. 690,606 views is a testament to how well delivered the material was in your video. As I find myself less and less confident in contractors of late, it is appreciated that you are providing content to empower viewers with knowledge that might have felt out of reach initially. Thanks again and many well wishes for continued success for you and your channel.
This was a fantastically simple overview of the engineering process needed to accurately specify a ducting system.
Here in the States among contractors, the most common method for duct sizing in residential is the "friction loss per 100 ft." method wherein we calculate the total equivalent length for the longest runs (both supply and return) and size everything based on getting the appropriate amount of air to these runs and balancing the rest with dampers.
Really wish there was an instructional video on this process (or even the equal friction method) in Imperial units out in UA-cam.
Thanks for providing such fantastic resources for the industry.
Look up the "ACGIH Industrial Ventilation" manual. You can download the 23rd edition for free on google. It has step by step examples.
Another good thing to mind when sizing ducts is the aspect ratio. Ashrae allows us to size on 1:4 basis while CIBSE mentions to size at 1:3.
*ASHRAE
Yeah this is pretty cool. Im a sheet metal apprentice, specializing in ductwork for commercial jobs. Interesting to see how the ductwork I make is designed and such. Great video!
I’m the same here just helped commission a job and was curious how they came up with air flow rates on the drawing and it’s pretty insane how much goes into it just for us to come along and make they’re job more fun 😂
As an engineer, this has help me a lot. Thank you so much for teaching and making useful video like this. Dont stop!
I got my Ac system installation almost a year ago, it smells very bad and when I turn it on it smells like dump wet bathroom. In order to get it to stop smelling I have to get the temperature down to 24, but then it's too cold😢 does anyone know if they have done for me a cowboy job, as I have spent a lot of money
@@victory6904 24 degree fahrenheit? Or Celsius. Either way you could have someone come potentially clean it, install uv lights or some sort of duct cleaning system. It sounds like it might be mildew caused by not properly insulated duct so it could be sweating and building up water that's smells gross. Could be improper drainage. Hard to diagnose something on the Internet just get a professional to look at it
As someone who has been doin HVAC design for a while, this is very helpful if you’re trying to understand the theory and calculations for the design. But in the real world, no one is going to build ductwork like yours because everyone is cheap and prefers round taps and tee junctions.
Are you interested in designing HVAC for a house I’m building? We’re planning on installing so I can’t find anyone who will just design it
Mulțumim!
Thank you!
great video man as always
and congrats for 100k subs.
Just want to say, this video fixed my exam project for HVAC
what is your project?
Great video! Very similar to how I learned in Applied Fluid Mechanics class!
Wow that’s like our HVAC course lectures❤
Great video, it's important to also note that's another driving factor for the mass flow rate is the fresh Air supply which is higher than your cooling or heating loads would override your video size
Agreed. This is where hydronics are strong - separating the ventilation needs from the load needs.
Amazing video, thank you. I noticed in the video (14.39) you are inputting the data into the interpellation website. that you input in Q11 value 0.14. Should it had been 0.15? (LOL) Its just me and no big deal. It kept me on my toes...so very helpful on your part. Love the videos.....THANK YOU
Great video this, can you also do a video on "calculating the cooling and heating loads using psychrometric charts" for HVAC systems? Really appreciate it if you can
refer to ashrae brother, so much easy to follow when you have ashre guidelines
You mention about heating and cooling load calculation on 1:15..have you already done the seperate video?
In calculating the pressure loss in the Tee Fitting, why do you only apply the dynamic loss formula in the straight direction and not in the bend too? For the bend you've only used the co-efficient of 0.3645 (15:45) and not used this in the dynamic loss equation, like you did after getting the co-efficient of 0.143 in the straight section (14:45).
was that a mistake ? or its how it done ?
I noticed that as well. It looks like an honest mistake.
watch How *AIR HANDLING UNITS* work here: ua-cam.com/video/KCiv8IAUkh8/v-deo.html
So much help in my project rn. Thanks bro.
Very informatory. I liked this a lot.
Just another very good simple method. Thank you
Error At minute 15:45 - for the H Tee branch G-I only the value of the loss coefficient was tabulated as 0.36 instead it should have been the value obtained when calculating the fitting loss as was done for the straight duct GJ which gave 0.93 Pa. some clarification needed here?
At point H, direction G-I, the correct value is 2.68, and not 0.36, so we would have to correct the subsequent calculations.
Great video, For the Tee 'H'at 15:45, is it not the bend coeff' 0.3645 taken from table using vel and area ratios, then using formula to find out the pr loss ?, It says straight from table, the coef 0.3645 as pr loss in Pa.
Pls clarify. Thanks.
Helped me in my project. Great work!!
great video, how about exhaust ventilation systems which is the opposite?
Hi
At 15:42 you calculated the C0 from the table and interbolation, and you forgot to calculate the P loss in the bend direction using the formula (P=C0*density*velocity^2/2)
,you have put it into the table directly
.
Plz notice that and if i'm Wrong tell us the Right plz.
Hmmm i notice that when u do consistency of units it come out like Kg/m.s2. idk maybe im wrong?
ايش الصحيح ؟
Love from India ❤
Excellent One. Thank you for your effort.
Very informative. I want to try doing HVAC at my home by myself. Thanks for the video.
Helpful and to the point explanation , thumbs up!
THANK YOU AND KEEP THE GOOD WORK.
Intro sounds chiller 😍
Thank you for this video, its very helpful. Do you have any thoughts on having the last take-off come off the end of the trunk (as you have designed in your example)? Most conventional advice says to take it off the side and cap the end to allow the trunk to pressurize.
You’re amazing fam.
Thank you, for giving great and more easily understandable video
Wonder how can we find velocity of air in duct to use for finding diameter of duct in chart ?
duct supplier has this table.
Sohrab:
Ques 4:-
Coefficient of pressure values of fittings like
Reducer=0.25
Elbow=0.27
It will varies or fixed according to CFM
Ques 1:-
During calculating static pressure only critical path will be taken or not ?
Ques 3:-
In formula
(F×L)/100
F= friction factor or friction head loss
Ques 2:-
we will calculate all the VCD OR only critical path?
Mantaps Good! Love This channel!
1:37 both cooling and heating are positive loads? Or cooling load is (+) and heating load is (-)?
You're paying for them either way. Cooling load is usually electricity, but because of the COP of the unit the actual amount of electricity used may be many times less than that calculated load, but you also have to consider the fans and the water used if it uses evaporative cooling or humidifiers. The heat load is usually natural gas here in Burgerland so you might end up using 5% or so more natural gas worth of heat than the load calculated due to the slightly inefficient nature of burning fuel (you can't breath the exhaust so the heat has to be transferred into usable inside air or another working fluid such as water in a hydronics system). Condensing heaters have come a long way at getting us up to 96% or more efficiency. In any case this is usually still cheaper because natural gas is many times cheaper than electricity is on a raw heating value BTU/hr (kWh) basis.
thank you for this video!!! it's very helpful!
great video..really helpful.thanks engineeringmindset.
how did you get velocity 5 m/s on the duct A, you didnt show it in the video, can somebody please axplaine?
Amazing videos seriously.
Nice and clear video, well done.
Do you have any videos on how to calculate proper condenser and evaporater size/capacity in relation to compressor size/capacity on custom AC units ?
If not please consider making one.
Thanks
Great video, I just have one question. When determining the mass flow rate, in the image it says to use delta T in terms of Kelvin but I believe you used your 8 degrees Celsius to get the mass flow rate for each room? Should we convert that into Kelvin?
Thank you for good detail’s of informations going keeping
i actually use simscale what a peace of software
Great video!!!
0:47
1:15
1:46
2:55
6:13
8:52
9:55
10:30
12:44
12:55
13:32
14:17
15:06
15:55
16:43
Can anyone explain why the Bend Loss Coefficient is used directly as the Dynamic Pressure Loss (15:40) rather than doing the Equation again as shown in 14:53 ?
New subscriber here, great video
Loved the video - can you make one with Imperial measurements for your slower US brethren? :) You can say - oh just use feet vs... However if the video was done all the way through with measurements we'd likely use, it would be easier to follow.
Great video. Really well explained!
Any plans of making a tutorial on how to read complex ductwork drawings?
pls can you do the cooling and heating load calculation
How do you get the values for cooling and heating loads?
Can you do a video on the Velocity Reduction Method?
very nice sir, HVAC&R ENGINEER from pakistan
Glad you enjoyed it
great video which helps me a lot.
Nice video! Grill style and size also effect static pressure but that's probably part of a different video
That was great, thank you!
Great video.
Thanks! You are awesome. 👍
The Engineering Mindset :- I have have not under stand Fitting example H : Outlet direction 2-Bend (Time 15:10 - 15:48). Calculated Velocity ratio and Area ratio, then based on that get coefficient 0.364 from bend table. My question is why don't we applied that coefficient value in pressure loss equation {pressure loss=coefficient x density x velocity Sq. / 2}. instead of that directly mention that vale 0.364 as fitting loss in Direction G-I. Anyone
please help
How to calculate If air grills fix directly on the duct ? E.g: air volume is 10800 m3/h and 10 SAGs fix on the duct. The pressure drop thru SAG? Thank bro
could you link me to the guide where to decide the air velocity?
where is the link for duct pressure loss chart?
how we are considering delta t as 8 in mass flow rate calculation?
Where can I find a duct pressure loss chart for rectangular ducts?
Fantastic and excellently explained. Does anybody know of any online calculation software or any programme that can help with sizing ducted airconditioning units and FCU's with the correct size ductwork?
Fitting loss in G-I direction should not be 0.36. I guess, 0.36 is the Fitting Coefficient. So, the fitting loss in G-I direction should be 2.65. Please correct me if I'm wrong. Thank you.
Hi, how to calculate the heating load and cooling load? 🙏🏻
Hello there, can you kindly make the simulation process video and upload?
Thankyou so much for this sir
How the Damper affect the CFM at 16:31
This is so freakin helpful
Hi,
Amazing video, really has helped me complete an assignment that I had no information on how to complete. However I'm still going to fail because you didn't calculate grilles. Also you stated that you would include the fitting tables you used in the video in the description, but it's not there and I have spend the last two hours looking for a god for saken fitting tables to no avail.
😕? I left 3 links for the exact books you need with all the information in, in the video description. You're welcome.
@@EngineeringMindset Aha! I see, in that case, thank you. Your videos are just so well put together and beautifully explained, you honestly really helped me out. Thank you for replying.
Out of curiosity, do you only need to bring fresh, conditioned air into the rooms? Is it not necessary to also suck out the stale air using a separate duct system?
can you also do a comparison of using one centralized hvac system versus mini-split units for the same size of a house having four bedroom and two floors. tks.
What velocity should I use in the pressure loss formula if fitting is a straight rectangular diverging duct?
@ 2:14 delta_T = 8 [Centigrade] but formula calls for [Kelvins], Is there a mistake in the Calculations ? delta_T should be 8+273.15 Kelvins not 8 Kelvins. Thanks
Delta_T should be 8. It a temperature *difference* between supply and return temps. Let say the supply temperature is 17 C and the return is 25 C. That's 290 K and 298 K respectively. Difference still is 8.
Great video!! Thanks for sharing!!
One question: What about split systems? How can I size the ductwork? is it necessary?
I have two comments :
First:
pressure loss for Tee G-I (bend) is less than G-J (straight) How ?
Second:
we need link for the duct pressure loss chart
thank you so much
Great video about Duct Design
I love it, thanks!!
Hi help please
In case we have an hrv or an erv the duct of return air coming out from wc where shall we connect it? Would we mix it with fresh air?
why is a fan selected based on only index run pressure loss , what about all other pressure loss in other branches ? fan need to pump air through the other branches right /? like pressure loss of AB+BC+DE+EF+EH+HL
Thanks for the video. Which software is best for industrial ventilation duct designing ? Most of the ducting part is round.
Great video..... Thank you so much
Hi Paul. What a brilliant video thank you very much!!! Can you put a link to the Duct Pressure Loss Chart you used please?
Link is in description, it's for the cibse book. I don't have the copyright for the chart so I can't share the chart unfortunately.
How Celcuis converted to Kelvin in this video of temperature difference ?
you put *fitting loss=0.93Pa* in the table for G-J direction by equating: coeff.(0.143Pa) x density x velocity out^2 ÷ 2
but for G-I diection, you just put value of *coeff.(0.36Pa)* into the table.
I didn't understand why didn't you applied fitting loss formula for G-I direction?
can anyone send me the static pressure chart? great video.
Do you know any free program to drawing the HVAC system? simple program are also helpful, tanks
Can you please upload full hvac system
Question: Why are two story homes, fitted with 2 units, but not ducted to accommodate 'convection'? Heat going up, cold falling. Returns are on the same floors as ducts for each unit. WHY?
Thanks for this video
U so much good and talent never giveup go ahead 😍😍🤗🤗 but this video so much fast ...
Very helpful