I'm studying for the HVAC P.E. and this one video helped me remember almost everything from thermodynamics and start making some headway on practice tests. Great video!
WOW, I must admit im still college and start first hvac job tomorrow, this video is really helping me. I couldnt get my head around these charts at all until this video, THANK YOU.
Thanks, I am going to start up an HVAC company, I just forgot about How to Read a Psychrometric Chart, but this video really helped me. Almost 4 years after Engineering
Believe it or not, I totally understood the chart in this 7 muinets and was much better than an hour and half in class room, thanks a lot and please keep the way you are of explaining and describing👍
Thank you for sharing the information to us. I do not have any background knowledge before, so there is a lot of things going on when I saw the chart at the first time. After I watch the video and research the chart for our group paper, it makes a lot of sense for me. Though I am still not familiar with this kind of chart, but at least I know what it is about and how can I use it in real life. By learning the psychometric chart, I think students in HVAC can access to this new tool to solve more difficult calculations and find solutions to problems. So in general, this is a very useful and helpful chart and this video illustrate how the chart works.
Ha! You're amazing teaching this subject. Not that is too complicated but it sometimes I get a bit confused and your video turned out to be very handy. It's helping study to my exam. Thank you alot!
Thank you very much! My teacher hasn't explained that the dew point temperature is read horizontally and I could't understand its difference from the dry bulb temperature on this chart.
One question. Outside temp is 32F, 80% humidity. Inside temperature is 70F and humidity stands at 40%. Let's say I open the window long enough for the air in the room to be fully replace by the outside air. Then I close the window and turn on the heating until I get 70F again. What will my humidity be? In other words, does this chart help me predict the humidity at a target temperature starting from a certain temp and humidity and adding heat without adding water in the air? Do I basically start from the intersection at 32F and 80% and draw an horizontal line until I hit the 70F vertical line and then read the humidity value on the curves?
By replacing the entire room air with the outside air, the moisture content of the outdoor air is much lower than the starting room condition, even though the outdoor air has a higher relative humidity. The starting room condition (70F/40%RH) has a moisture content of 43.66 Grains/lb. While the outside condition (32F/80%RH) has only 21.19 Grains/lb. If sensible heat only is now applied into the room (e.g. a room convective heater) then this will move in a horizontal straight line from left to right on the psych chart. If the dry bulb temperature increases to 70F, the moisture content will stay the same at 21.19 Gr/lb, but the relative humidity will fall to 19.5%. This assumes that the room does not have any sources of latent load such as people or plants etc that would increase the moisture content of the space while the room is being heated
@@TitusHVAC Thanks for confirming. I've just subscribed to your channel. Greetings from a degree qualified Mechanical Engineer getting a bit rusty having worked in oil and gas for 15 years now :)
The knowledge you have shared with us is very interesting & you are great 👍. May I know your profession, is it Mechanical Engineering with focus in HVAC systems design or Architecture? Thanks
Great video, For the first time I understood enthalpy is the heat or energy with two components, due to sensible part we see drop in DBT & the other is latent used for evaporation & the potential drop in temperature determines how soon or later we will see water condensation, if the drop on DBT to WBT is lower it is closer to 100% relative humidity, if this drop is higher then RH is away from maximum possible 100%. & the DP also goes even lower accordingly, as evident, the gradient of DP is zero or much lower than WBT, & the reduction in depression & DP is also similar. When we hear weather, the weather person mentions RH & Dew Point, rain or no rain, muggy or comfortable, how should we understand weather from DBT, RH, DP, moisture content? Can we use Psychrometric chart to understand if it will rain or not, it will be muggy or not, & how? Could clarify how to use the concepts of DP, RH, moisture content to understand weather?
+TitusHVAC Thanks a lot. It really helped. I have a query. What if i have the DBT and WBT, and i have to find the enthalpy. I point out the intersection and draw a line to the enthalpy line, but the intersection is arbitrarily in the middle of two specified enthalpy values. How do I find the correct enthalpy value now?
When we hear weather, the weather person mentions RH & Dew Point, rain or no rain, muggy or comfortable, how should we understand weather from DBT, RH, DP, moisture content? Can we use Psychrometric chart to understand if it will rain or not, it will be muggy or not, & how? Could clarify how to use the concepts of DP, RH, moisture content to understand weather?
Q1: A main duct with dimensions 0.6 ×0.6 m carries air at the rate of 280 m3/min. It is divided into two ducts, one being 0.6 × 0.3 m and the other is 0.6 ×0.45 m. If the mean velocity in the larger branch is 9 m/sec, calculate the mean velocity in the main duct and the other branch. Also find the mean velocity pressure in each duct assuming standard air density of 1.2 kg/m3 . Q2: The following figure shows a typical duct layout. Design the duct system using Equal friction method. Take the velocity of air in the main duct (AB) as 8 m/s Hi Can i get an answer
In an air washer installation, 100 m3/min of air at 5 oC DBT and 80% relative humidity has to be heated and humidified to 25 oC and 45% of relative humidity by the following processes; (a) preheating, (b) adiabatic saturation in a re-circulated air washer up to 95% relative humidity and then (c) reheat to final state. Calculate: 1. total heat added in kW 2. water mass to be provided to the washer and 3. humidifying efficiency of the air washer. You can find solutions to this question
1) Starting point 1 is 5C (41F) and 80% RH. The humidity ratio (W) is 30.3 grains/lb (0.0043 lb/lbm-da) and enthalpy is 14.52 Btu/h-lbm. Density of mixture is 0.079 lbm/ft3) 2) Sensible pre-heating (constant humidity ratio) process (a) brings mixture to 55.4F (13C) at point 2 3) Moisture addition (process b) at constant dry bulb brings mixture to 55.4F, 95% RH (W = 62.6 grains or 0.0089 lb/lm-da) 4) Final sensible heating (process c) brings mixture to 77F (25C) and 45% RH (W = 62.6 grains or 0.0089 lb/lbm-da). Enthalpy (h) of final mixture is 28.27 Btu/h-lbm.
The volume flow rate specified is 100 m3/min or 3,528 CFM. The mass flow rate (M) in pounds mass per hour can be determined by the following equation: M = FT3/min x density (lbm/ft3) x 60 min/hr = 3,528 x 0.079 x 60 = 16,723 lbm/h The total heat added in Btu/h is equal to M x (h4 - h1) = 16,723 x (28.27 - 14.82) = 225,924 Btu/h or 65.9 kW The water mass added is equal to M x (W4 -W1) = 16,723 x (62.6 - 30.3) =540,153 grains or 77.16 lbs (35 kg)
The exact meaning of absolute humidity is different, depending on who you ask. The way I learned it, was an interchangeable definition with humidity ratio, where it is the mass ratio of water to dry air. I find this to be the most useful version of it, since every application I've ever used it for, I needed either as a mass or molar ratio, and didn't want to even think about volume. Other variants define it as a ratio of water vapor mass to partial volume of dry air, or volume of the aggregate mixture, which I find to be a useless way to measure it. The density is going to change during any process you care to study on this chart, so you want to use definitions of humidity that are independent of density.
I have a problem. Now assume in a closed room we have found the RH and dry bulb temp. Thus, the specific volume of the room can be found. The specific volume should be constant as the room has a fixed amount of dry air. Now if the room is slightly cooled down then the point marked on the psychrometric chart should be shifted to the left and therefore the specific volume would change according to the chart. How can this be?
Kalana Suraweera the chart assumes a specific pressure. If the room was actually sealed air tight, the pressure would reduce and the chart would change slightly to account for the change in density.
Why is dew point in the weather report many a time at RH less than 100% & it rains. Has it got something to do with pressures like 29.9 inch or less, or wind speed, density or cloud formations, adiabatic cooling due to lower pressures? Thanks I am trying to understand weather, rain & snow
Armed with a chart with the Enthalpy Correction Curves plotted, it’s a simple case of plotting the specific condition on the chart then reading the “Specific Enthalpy at Saturation” take this number and subtract the “Enthalpy Deviation Correction” factor read from the specific point on the curve, its very straightforward but only if you have a chart with these curves plotted of which I could not find one in IP units. This is because Enthalpy Deviation is only used in applications requiring extreme accuracy and is generally not used in HVAC.
An hour's worth of a lecture covered in 10 mins. Cool.
I liked it short and concise, I can pause and learn. Please keep it this way! Great style!
It is incredible to fit this subject into 7 minutes, thanks a lot!
Where my fellow engineers at?
Studying
yaya boi
Fellow engineer here
Im just here physically, mentally im done with engineering :/
@@muhammadsheikh9413 it's all gonna be worth it bro. keep grinding ! :D
I'm studying for the HVAC P.E. and this one video helped me remember almost everything from thermodynamics and start making some headway on practice tests. Great video!
WOW, I must admit im still college and start first hvac job tomorrow, this video is really helping me. I couldnt get my head around these charts at all until this video, THANK YOU.
I'm glad they helped :-) Have a great weekend!
Thanks, I am going to start up an HVAC company, I just forgot about How to Read a Psychrometric Chart, but this video really helped me. Almost 4 years after Engineering
Believe it or not, I totally understood the chart in this 7 muinets and was much better than an hour and half in class room, thanks a lot and please keep the way you are of explaining and describing👍
outstanding lady... thanks for your help
Thank you for sharing the information to us. I do not have any background knowledge before, so there is a lot of things going on when I saw the chart at the first time. After I watch the video and research the chart for our group paper, it makes a lot of sense for me. Though I am still not familiar with this kind of chart, but at least I know what it is about and how can I use it in real life. By learning the psychometric chart, I think students in HVAC can access to this new tool to solve more difficult calculations and find solutions to problems. So in general, this is a very useful and helpful chart and this video illustrate how the chart works.
My professor couldn't explain it to me within half an hour, and here is 7 minute video and i understand everything.
Very helpful explanation of how to use a psychrometric chart!!
You're welcome!
Pls link sand ,I want to join your FB,Instagram,what's app group , it is best advice and any exam
Nice, i have stay awake at 1am just to finish my report about humidity. Thanks you for explaining
Very precised...thanks a lot.My Professor just provided us the slide and a short lecture on it that was tough for me to capture then.Keep this up
subscribed! you are a great assistant to the books!
Great summary! Thank you!!!
Ha! You're amazing teaching this subject. Not that is too complicated but it sometimes I get a bit confused and your video turned out to be very handy. It's helping study to my exam.
Thank you alot!
This really helps. Thanks a lot for your support
Thank you very much! My teacher hasn't explained that the dew point temperature is read horizontally and I could't understand its difference from the dry bulb temperature on this chart.
it's really cool! thanks a lot!
Extremely useful video! Thank you.
Thanks for sharing! Gotta try it with my exercise...
Thanks and relatively cool, figuratively and absolutely!
Thank you Titus hvac for learn me Psychrometric chart.
pinaki biswas mlm
Thank you very much for creating this video.
One question. Outside temp is 32F, 80% humidity. Inside temperature is 70F and humidity stands at 40%. Let's say I open the window long enough for the air in the room to be fully replace by the outside air. Then I close the window and turn on the heating until I get 70F again. What will my humidity be? In other words, does this chart help me predict the humidity at a target temperature starting from a certain temp and humidity and adding heat without adding water in the air? Do I basically start from the intersection at 32F and 80% and draw an horizontal line until I hit the 70F vertical line and then read the humidity value on the curves?
By replacing the entire room air with the outside air, the moisture content of the outdoor air is much lower than the starting room condition, even though the outdoor air has a higher relative humidity. The starting room condition (70F/40%RH) has a moisture content of 43.66 Grains/lb. While the outside condition (32F/80%RH) has only 21.19 Grains/lb. If sensible heat only is now applied into the room (e.g. a room convective heater) then this will move in a horizontal straight line from left to right on the psych chart. If the dry bulb temperature increases to 70F, the moisture content will stay the same at 21.19 Gr/lb, but the relative humidity will fall to 19.5%. This assumes that the room does not have any sources of latent load such as people or plants etc that would increase the moisture content of the space while the room is being heated
@@TitusHVAC Thanks for confirming. I've just subscribed to your channel. Greetings from a degree qualified Mechanical Engineer getting a bit rusty having worked in oil and gas for 15 years now :)
Thank you ! Helped out a lot.
The knowledge you have shared with us is very interesting & you are great 👍.
May I know your profession, is it Mechanical Engineering with focus in HVAC systems design or Architecture? Thanks
Thank you for making it SO MUCH easier 🌼
Thanks a lot! It turned out to be very useful; I study architecture and I was having a hard time with this chart...
Very well done. Thank you!
Amazingly helpful video!
This was wonderful. Thank you!
This is great. Thank you for the video
Many thanks for your information . it was perfect .
Apart from my mum this lady is the best
oh thank you very much..tomorrow is my exam and you have solved my problem
awesome video... now let's all use international units - IU, in all countries... :P
Great video,
For the first time I understood enthalpy is the heat or energy with two components, due to sensible part we see drop in DBT & the other is latent used for evaporation & the potential drop in temperature determines how soon or later we will see water condensation, if the drop on DBT to WBT is lower it is closer to 100% relative humidity, if this drop is higher then RH is away from maximum possible 100%. & the DP also goes even lower accordingly, as evident, the gradient of DP is zero or much lower than WBT, & the reduction in depression & DP is also similar.
When we hear weather, the weather person mentions RH & Dew Point, rain or no rain, muggy or comfortable, how should we understand weather from DBT, RH, DP, moisture content?
Can we use Psychrometric chart to understand if it will rain or not, it will be muggy or not, & how?
Could clarify how to use the concepts of DP, RH, moisture content to understand weather?
thank you mam for your good teaching.
Thank you, you totally saved my day!
very helpful video!!
Well done. Go ahead
Thank you for your cool video.
very nicely explained
Thanks a lot for this great video. Came in very handy just before the exams :-)
Thank you alot for your excellent toutrial, Please I need the graph colored in pdf form if you can?
screenflicker1, sorry, I often forget to slow down when I talk. Thanks for the reminder.
+TitusHVAC Thanks a lot. It really helped.
I have a query. What if i have the DBT and WBT, and i have to find the enthalpy. I point out the intersection and draw a line to the enthalpy line, but the intersection is arbitrarily in the middle of two specified enthalpy values. How do I find the correct enthalpy value now?
If you fall between two lines, you can interpolate the value.
Very useful! Thank you
When we hear weather, the weather person mentions RH & Dew Point, rain or no rain, muggy or comfortable, how should we understand weather from DBT, RH, DP, moisture content?
Can we use Psychrometric chart to understand if it will rain or not, it will be muggy or not, & how?
Could clarify how to use the concepts of DP, RH, moisture content to understand weather?
Thanks for this video Bro!I just learned something new, Good job!!!
Can you help me solve the problems
simply amazing
Thank you. Very helpful.
hi cute girl..what,s up?....
Thanks so much it really help me alot.
Q1: A main duct with dimensions 0.6 ×0.6 m carries air at the rate of 280 m3/min. It is divided into two ducts, one being 0.6 × 0.3 m and the other is 0.6 ×0.45 m. If the mean velocity in the larger branch is 9 m/sec, calculate the mean velocity in the main duct and the other branch. Also find the mean velocity pressure in each duct assuming standard air density of 1.2 kg/m3 .
Q2: The following figure shows a typical duct layout. Design the duct system using Equal friction method. Take the velocity of air in the main duct (AB) as 8 m/s
Hi
Can i get an answer
Unfortunately we cannot provide the duct calculations for these questions as that is not the premise that our podcasts were designed for.
literal queen
Thanx v. Helpful
Good job Madame
You savved my life thanks from poland
In an air washer installation, 100 m3/min of air at 5 oC DBT and 80% relative humidity has to be heated and humidified to 25 oC and 45% of relative humidity by the following processes; (a) preheating, (b) adiabatic saturation in a re-circulated air washer up to 95% relative humidity and then (c) reheat to final state. Calculate: 1. total heat added in kW 2. water mass to be provided to the washer and 3. humidifying efficiency of the air washer.
You can find solutions to this question
1) Starting point 1 is 5C (41F) and 80% RH. The humidity ratio (W) is 30.3 grains/lb (0.0043 lb/lbm-da) and enthalpy is 14.52 Btu/h-lbm. Density of mixture is 0.079 lbm/ft3)
2) Sensible pre-heating (constant humidity ratio) process (a) brings mixture to 55.4F (13C) at point 2
3) Moisture addition (process b) at constant dry bulb brings mixture to 55.4F, 95% RH (W = 62.6 grains or 0.0089 lb/lm-da)
4) Final sensible heating (process c) brings mixture to 77F (25C) and 45% RH (W = 62.6 grains or 0.0089 lb/lbm-da). Enthalpy (h) of final mixture is 28.27 Btu/h-lbm.
The volume flow rate specified is 100 m3/min or 3,528 CFM. The mass flow rate (M) in pounds mass per hour can be determined by the following equation:
M = FT3/min x density (lbm/ft3) x 60 min/hr = 3,528 x 0.079 x 60 = 16,723 lbm/h
The total heat added in Btu/h is equal to M x (h4 - h1) = 16,723 x (28.27 - 14.82) = 225,924 Btu/h or 65.9 kW
The water mass added is equal to M x (W4 -W1) = 16,723 x (62.6 - 30.3) =540,153 grains or 77.16 lbs (35 kg)
Amazing
Please give this Phsicometric chard pdf
www.engineeringtoolbox.com/docs/documents/816/psychrometric_chart_29inHg.pdf
When you in med school but you gotta know how to use this coz humidity's a bitch in a hot day and can give you a heatstroke.
thanks fam.
It was more clear and help full
very informative
Thank you so much, could you sent to me a psychometric chart.
This was good. However, I don't think Absolute Humidity is the same as Humidity Ratio. They have different units per ASHRAE.
The exact meaning of absolute humidity is different, depending on who you ask. The way I learned it, was an interchangeable definition with humidity ratio, where it is the mass ratio of water to dry air. I find this to be the most useful version of it, since every application I've ever used it for, I needed either as a mass or molar ratio, and didn't want to even think about volume.
Other variants define it as a ratio of water vapor mass to partial volume of dry air, or volume of the aggregate mixture, which I find to be a useless way to measure it. The density is going to change during any process you care to study on this chart, so you want to use definitions of humidity that are independent of density.
thnx,. that's informative ...
Great, thanks
if two intersection point is out of graph can we find other physical properties?
Thanks a lot!!!!!!
I have a problem. Now assume in a closed room we have found the RH and dry bulb temp. Thus, the specific volume of the room can be found. The specific volume should be constant as the room has a fixed amount of dry air. Now if the room is slightly cooled down then the point marked on the psychrometric chart should be shifted to the left and therefore the specific volume would change according to the chart. How can this be?
Kalana Suraweera the chart assumes a specific pressure. If the room was actually sealed air tight, the pressure would reduce and the chart would change slightly to account for the change in density.
Great !
These units are wild lmao
Awesome
Simplified.... Nice...
Thank you!
Why is dew point in the weather report many a time at RH less than 100% & it rains. Has it got something to do with pressures like 29.9 inch or less, or wind speed, density or cloud formations, adiabatic cooling due to lower pressures?
Thanks
I am trying to understand weather, rain & snow
Because liquid water falling through the air (rain) is different than the amount of water vapor in the air.
Because the rain is originating in clouds at a much higher elevation, rather than fog at ground level.
thankyou so much
THANK YOU SO MUCH!!!!
can you pls post the link for the psychometric chart used in the video?
www.titus-hvac.com/file/11849/fc_guidelines2018.pdf - page B71
Why would someone downvote this video?
Omg I finally get it haha!!
use metric units please and thank you
Pls pls hhhh it's a struggle out here
I'm a little confused. I tried your example on the chart in my book and got slightly different numbers.
Is this a standard chart?
it was really useful
Now, let's get this out of the way and
Thankyou!
Thanks
what's the difference between absolute humidity and specific humidity?
It's the same thing
realy very easy than calculations
thanks!
How to calculate the enthalpy deviation from the curve ??
Armed with a chart with the Enthalpy Correction Curves plotted, it’s a simple case of plotting the specific condition on the chart then reading the “Specific Enthalpy at Saturation” take this number and subtract the “Enthalpy Deviation Correction” factor read from the specific point on the curve, its very straightforward but only if you have a chart with these curves plotted of which I could not find one in IP units. This is because Enthalpy Deviation is only used in applications requiring extreme accuracy and is generally not used in HVAC.
@@TitusHVAC thank you 😀
Perfect.
Thank you very much , this was very helpful
little too fast but great break down of info. Thank you!
wow i just fell in love ....
really thanks.. for tutorial... mam...
Superrr very easy to get mind all parameters ... good pattern..