Transcript
00:00:00Michele De Carli: A girl. And we start with the the
00:08:890Michele De Carli: okay, we are going to see now how to design the whole air distribution network. Okay.
00:16:840Michele De Carli: we start and we and we conclude, tomorrow, okay.
00:21:487Michele De Carli: I will go quite quick because I want to.
00:29:180Michele De Carli: Most of these lights. Okay, will be we'd be
00:36:633Michele De Carli: will be used again by Marco Marigo.
00:40:370Michele De Carli: And who will show you the slides and the tool. Okay, we are going to provide you an excel based tool. Okay? Very nice.
00:50:840Michele De Carli: I think. Okay. Because it's it's quite easy. Okay? And we'll help you in designing and sizing the plant. Okay. So now we are going to see how to size the plant, the the whole air distribution. Okay? So
01:14:430Michele De Carli: one important issue, which what should we at the end. Choose. We have to choose the section, the cross section of the dots, okay in each, in each section
01:26:645Michele De Carli: in each part of our, let's say, in each part of our of our distribution
01:33:350Michele De Carli: back to work. Okay? So
01:37:720Michele De Carli: of course, if we keep the cross section small, we could save money. Okay? Because the the smaller the cross section, the cheaper will be the doctor. Okay?
01:56:551Michele De Carli: But of course, if we decrease to match the cross section, we will increase the pressure drop. The linear pressure drops the continuous pressure drop.
02:05:820Michele De Carli: Okay? And of course, if we
02:09:139Michele De Carli: decrease to match the cross sectional area of our adapter.
02:13:270Michele De Carli: The speed, the velocity inside of the stack will increase that much, and if we go above a certain value of the velocity we could produce inside. As I told you, as we have seen, we are putting a silencer between the air handling unit and the rules. Okay, in order to
02:32:600Michele De Carli: stop the noise, to reduce the noise of the fan, and then what we have to consider is to limit the turbulence inside of the dots in order to avoid noise reduction in the dots. Okay? Because we we, this is what we have to.
02:52:620Michele De Carli: So let's have a look at the sketch. Okay? And these are, let's say, this is a, let's say, a sketch of what we have. So basically.
03:01:730Michele De Carli: this is the air handling unit. Then we have the ducts. Okay for
03:08:70Michele De Carli: intake in the air from outside and to blow the air outside. That shows the air. Okay?
03:15:869Michele De Carli: Then we have the air and unit. And then we go into the the building. Okay? And we have the principal or main dots. Okay? And then we have secondary dots. Okay, so from the air and unit. We
03:34:430Michele De Carli: go outside with one duct we have the principal or main ducts. And then we are going to distribute. Okay, the air into secondary ducts, and then from secondary ducts, we will do the the air terminal devices. Okay, so these are the recommended air velocities. So, as I told you the the we want to keep the velocity.
04:02:752Michele De Carli: Not too high. If we if we exceed these velocities. Okay, these are energy velocity. Then the noise generated inside our darts will be
04:14:10Michele De Carli: to be okay. And that that means that you will have
04:19:70Michele De Carli: noise. Okay? Problem in the in your
04:24:64Michele De Carli: getting the orientation system. So you can see, of course, the residential, like hotels. Okay, are
04:34:740Michele De Carli: uses where you need to keep the
04:39:150Michele De Carli: noise level. Okay? Because there are silence or quiet places. Okay? And of course, it is much more critical.
04:50:230Michele De Carli: because they are not or noise. Okay, like in offices or industrial buildings. Okay, some noise you have always in offices. And while for in residential buildings, or you know, hotels, what you want is to keep
05:07:340Michele De Carli: quiet. Everything. So you can see 4 meters per second is the main duct velocity. The secondary duct is 3 meters per second, and then this is the outlet and the the return times. Okay, so you can see that the velocity
05:26:240Michele De Carli: going from the air in the unit towards the air terminal devices has to be reduced. Okay, once you go to line that
05:34:960Michele De Carli: secondary duct and then to the air terminal devices. Okay.
05:41:717Michele De Carli: give me just 5 min. Okay, what about the the pressure losses.
05:49:685Michele De Carli: We
05:52:619Michele De Carli: we have continuous losses and localized losses. Okay, localized losses. We have seen one of them. One of them is their air terminal device
06:04:360Michele De Carli: pressure losses. We have seen between 15 to 40. Okay, from 10 to 40, 50, even sometimes. Pascal. Okay, so this is the pressure loss that you have the pressure drop that you have across the air terminal device. But of course, we have also some other okay,
06:25:360Michele De Carli: localized pressure loss for the continuous pressure drop. Okay? You know, you have seen from the fluid dynamics basic courses, the linear pressure locks since sorry are related to the friction factor. F, okay.
06:47:960Michele De Carli: the
06:49:490Michele De Carli: square of the velocity. And of course, at the denominator we have the diameter. Of course, the smaller diameter, the greater the fraction here, plus, okay.
07:04:70Michele De Carli: okay.
07:10:70Michele De Carli: for the linear loss. What we are going to see tomorrow, okay, is how to calculate. Of course, you have to think about that what we have seen in the
07:19:960Michele De Carli: in the the for the air terminal device. This is to be done just at the end of the or in the final design
07:29:905Michele De Carli: stage. Okay?
07:33:120Michele De Carli: what you have to think about is that you? Now we are going to see how to move from the preliminary design to the final design. So the preliminary design phase, you don't have to really go in detail the the distribution network. Okay? But we are just to let's say, check, which could be the
07:55:770Michele De Carli: general size. Okay of your dots. Okay, by considering the velocities that you have here, and by considering, let's say, a a a rough
08:07:550Michele De Carli: size of your data. And that is done with this.
08:12:430Michele De Carli: the graph that we are going to see tomorrow. Okay.
08:16:440Michele De Carli: alright. So we stop here and we meet tomorrow at 2 30, you say.
08:26:100Michele De Carli: Have a nice afternoon.