Trascrizione
00:00:150Michele De Carli: Melka.
00:03:650Michele De Carli: No? Okay. So we start with that.
00:32:242Michele De Carli: So we are okay. We started with the lecture and
00:43:420Michele De Carli: So 1st of all, I would like to remind you that we are going to see right now. Weekly. Okay, I will. I will
00:54:600Michele De Carli: give some points which then, are not really touched by Marco Marigo, who will then show you how to
01:04:170Michele De Carli: deal with the the project that you have to do.
01:07:870Michele De Carli: I would like to remind you that in moodle there is still time to to sign in. You can sign in. You didn't sign in.
01:16:510Michele De Carli: did you? You did?
01:19:566Michele De Carli: Okay, yeah.
01:21:145Michele De Carli: Alright. And then we see, okay, we can. We will. We'll manage
01:26:520Michele De Carli: you to be in a group. Okay?
01:29:161Michele De Carli: So we were talking yesterday about the sizing. I told you that for the continuous drops
01:38:532Michele De Carli: you can use this chart here, and preliminary phase, preliminary
01:53:460Michele De Carli: and design. Maybe.
01:57:460Michele De Carli: Then, we have user to support 5.
02:00:680Michele De Carli: Yeah, you better. Yeah, intermediate perspective that these are the
02:14:491Michele De Carli: these are the the steps. Okay? So in the preliminary design. You have to make a sort of evaluation on the space that you need to.
02:30:519Michele De Carli: For the main dots. Okay, so main dots are the dots from the air handling unit to the second. That's okay. And then also for the secondary. That's but you don't really look in detail on the air terminal devices, and so on.
02:47:250Michele De Carli: So the beginning, what you should do in order to check if the the space need for certain for a certain doctor, okay, for a certain air system. You can use this chart here, what is this chart showing? Basically, this is the recommended area for your
03:17:730Michele De Carli: for your doctor, which is set the cross-sectional area of your doctor.
03:22:901Michele De Carli: Usually, as I told you yesterday, usually the best would be to have a
03:30:70Michele De Carli: pressure, a linear pressure drop of one Pascal per meter. Okay, but 2.
03:35:670Michele De Carli: If it is a little bit more, it it is not.
03:41:750Michele De Carli: It is not a crime. Let's say, okay. So even 2, Pascal per meter is okay. Okay. Still, okay.
03:49:60Michele De Carli: Batteries. One per step. But of course, if you are the
04:00:180Michele De Carli: okay, the diameter is affecting the.
04:02:940Michele De Carli: So, as I told you, the the choice of the size is a compromise between the initial cost, because the greater the doctor, greater the cost. Okay. But at the same time the the greater deductor, the lower will be the okay. So one is that then that this is the optimal line. Okay, so this is the optimal.
04:30:710Michele De Carli: the optimal.
04:33:220Michele De Carli: Okay. But to see the gray area is okay. So you could recipro even accepted more even than to. Okay. So it depends on the space that you are that you have available. Let's suppose, for instance, that you have like, 1,000 liters per second. Okay, which is 3,600 cubic meters per hour. Okay?
05:02:784Michele De Carli: So in this case they up you? You could. Sorry.
05:08:320Michele De Carli: Let's see.
05:10:280Michele De Carli: Sorry this is okay. So then you go straight on with the with the vertical line, right? And in this case, the optimum
05:22:450Michele De Carli: section would be this one here. Okay, that I have highlighted, which is 450 is the diameter. So this is the diameter in
05:34:360Michele De Carli: millimeters. Okay?
05:41:490Michele De Carli: And you can see, of course, that you, this is the OP.
05:48:120Michele De Carli: But still, if you have a cross sectional area, 400 is okay, because you are in the in the gray area, which means about less than slightly less than 2 Pascal per meter. But it could be that 3 is also a good option. Okay, still, which means round about 3 Pascal per meter.
06:09:225Michele De Carli: So this is the diameter of the okay, so this is
06:15:760Michele De Carli: 35 to 45 cm of time.
06:28:970Michele De Carli: as I told you, or, as we have seen, may most of the time, or usually. We use
06:37:610Michele De Carli: rectangular or square dots. Okay? So how you go from the diameter to the to the
06:45:740Michele De Carli: to another shape of the doctor. Well, you can use this equation that you can see here, or you can go down in the other chart where you can see that the equivalent diameters are are put here. Okay? So these are the diameters. Okay?
07:08:250Michele De Carli: And in this case you said, we are in between 350 and 450. Okay? Which means that basically, you can select the size of the of the doctor in I mean in the.
07:24:290Michele De Carli: it was okay. So
07:26:400Michele De Carli: Amd, okay? So in this case you can, for instance, select the dot which is like 600 or 60 cm by, let's say, about 20 cm, or you can have, let's say, 6 in this case, diameter of 35
07:51:590Michele De Carli: millimeters. Okay, 350 but you will have higher pressure losses, because in that case we have seen that you have more or less 3 Pascal per meter with 450 then in this case you could have 6, 60 cm by 30 cm. Okay.
08:12:731Michele De Carli: and or you can even have one meter. Okay? Times. Let's say, if this is the case.
08:22:290Michele De Carli: you have one meter by one by 1030 meters. Okay? Which is, I mean, it's not that use
08:29:173Michele De Carli: you, not the common or 100 meter by
08:32:850Michele De Carli: 20 cm. Okay, so that depends
08:39:299Michele De Carli: in space that you have available in the
08:46:220Michele De Carli: from the architecture.
08:51:510Michele De Carli: And okay, because usually the the dots are hidden. Okay, in the 4 siblings. Right? Okay? So above this 4, Syling.
09:03:280Michele De Carli: as I told you, usually, you can have
09:06:530Michele De Carli: 50 60 cm available. Okay, so this is more or less the height that you have you, you have available. You have to remember that, of course, this case
09:20:110Michele De Carli: he sees this level. Okay? And you end up in
09:25:690Michele De Carli: doctor. Okay? And you have to remember that usually we have
09:29:680Michele De Carli: supply and the return act. So you take into account that we have 2 tax actually, okay, usually running, for instance, in the corridor. And
09:44:600Michele De Carli: yeah, the insulated, they supply that because usually they supply, that is with the
09:58:830Michele De Carli: system, but also with
10:05:740Michele De Carli: this is because otherwise a conversation on the rooms of the
10:19:40Michele De Carli: okay, so display supply that has to be usually okay?
10:26:160Michele De Carli: insulated. Okay, they return that. Not necessary because it's a center.
10:32:240Michele De Carli: Thanks for Becky.
10:33:630Michele De Carli: Very quiet. But they they supply that it. It has to be.
10:37:490Michele De Carli: So, for instance, we, if you have 2 features available. Okay.
10:43:760Michele De Carli: then you, of course. Yeah, you have to think about 5 cm of installation. So that means that.
10:53:770Michele De Carli: Yeah.
10:56:212Michele De Carli: you are using 10 cm from 1 point and the other because of the insulation. So at the end, 60 cm is suitable. Okay? Value.
11:12:670Michele De Carli: You have to think that then space for them to work. You have to hang up, so you need to go with your hands, so
11:20:20Michele De Carli: you need at least, let's say
11:36:00Michele De Carli: 36,
11:38:20Michele De Carli: maybe 3 meters better. Okay? So you have 50 cm here, 50 cm, because then you have 33.
11:48:520Michele De Carli: So at the end, let's say one Friday bye.
12:01:575Michele De Carli: because you have to. Of course, you have to hang up the last
12:10:610Michele De Carli: alright. So this is what you should do at the beginning in the Premier.
12:15:450Michele De Carli: In your design you have to check that. You have enough room. Okay, if you have not enough room, you have to tell the that you have not enough room. Okay?
12:23:880Michele De Carli: And this is a kind of, let's say, fight between the architects. And in order to find enough place for for your technical issues. Okay, but it's fine, it's not.
12:39:610Michele De Carli: And so at the end you have the
12:50:300Michele De Carli: you have to consider, then the equivalent diameter, and from the equivalent diameter. Then you select the dimensions of your rectangular one.
13:01:196Michele De Carli: Yes, so you do that, for let's say, in the preliminary case you can use this chart. Then, in the final design, you're going to use the equations, and the tool which will be presented afterwards is based on these equations. Okay, so you, you do the proper calculation, taking into account the different
13:24:990Michele De Carli: in detail, the continuous pressure drops
13:29:623Michele De Carli: the continuous pressure drops. Of course they have to be multiplied by the length of the of the duct, and then you get the lapses.
13:38:940Michele De Carli: But the linear losses. You have also the
13:42:830Michele De Carli: localized losses. Okay, so localized losses
13:46:380Michele De Carli: are present. Anytime you have a change in direction, or every time you're mixing to air rates or air flow rates, or you are dividing to
13:59:50Michele De Carli: flow rates. Okay, what is important that you remember? Is that with the with the air, okay, here, you cannot do. Okay, this is not really recommended. Okay, so you have to make the curves. Okay. So you cannot change your direction with an L,
14:22:180Michele De Carli: because that will create too many turbulences and too noise. Okay? Generated into the diet. So what you should do? You have to consider that.
14:32:396Michele De Carli: whatever is the section. So in the case of rectangular or circular section. You need to to to
14:41:10Michele De Carli: a curve. Okay, in order to avoid the noise generation into the dock. Because if you use this kind of system. Okay, you can see that here there are special devices that are special
14:56:350Michele De Carli: wheels or something
14:59:280Michele De Carli: similar. Okay? But in any case, this should be avoided. Okay, so you need the the curve. Okay with the water. We will see that in this case you can use L shape.
15:16:660Michele De Carli: it is not a problem, but with with the air. You cannot do that.
15:21:170Michele De Carli: And of course, when you have to change the when you have to split your air okay, into 2 different air streams, or you want to have, or you want to mix the air. Then also, in this case, you should use this kind of system here. Okay, which is a double curve system.
15:44:90Michele De Carli: And as you can see, you have the different types of localized pressure lobs. Okay, which is expressed with the C
15:55:50Michele De Carli: element of the key element, then, is a value that you use anytime. You have a a certain
16:02:670Michele De Carli: localization. So of course, then not the last or
16:08:20Michele De Carli: the last, but not the least, is the air technical device, which is, of course, a pressure, a localized pressure loss. And, of course. Another pressure loss that you have to consider is then the air handling unit
16:21:990Michele De Carli: pass through the filters, the as we have seen, the the grease, the dampers, the filters, the coils right the silencer, and this is everything you should take into account as of course, boxes. Of course
16:41:810Michele De Carli: the platinum every time you have a platinum every time you, you want to stabilize a a flux. Okay, that is also a, a, a, a a
16:54:590Michele De Carli: localized logs. Okay? So you have a lot lots of different
17:03:410Michele De Carli: now, which are the steps for the design. So what should you do when you design an air distribution system? So 1st step, the 1st point is to
17:17:99Michele De Carli: check.
17:18:170Michele De Carli: Okay, where you can, they locate where you can place the air handling unit. Okay? So the air handling unit is a box. Then it is it is it needs okay, space. Okay? Remember also this day that
17:41:810Michele De Carli: this is the for you of your every unit. You need the at least one meter. Okay?
17:56:290Michele De Carli: Now, in order to work, okay, to make maintenance to work, and so on.
18:03:200Michele De Carli: Also what you have to check in case you are putting unit inside of your or your building
18:09:770Michele De Carli: is that you have enough for
18:17:810Michele De Carli: the the passages that you may find. So we have to check that. Of course, if it's on the roof.
18:28:270Michele De Carli: then you have to check that. The
18:30:790Michele De Carli: weight of the unit, the structures of your of your steps are able to let's say to
18:39:700Michele De Carli: to allow to have the weight of the lens. Okay? So in this case, you have to really to check the the space, the available space and or
18:51:651Michele De Carli: structures that are allowing you to have to her. Yeah.
18:59:950Michele De Carli: very important is also noise and vibrations. Okay, noise and vibration. So about the vibrations, you should put some bankers
19:17:740Michele De Carli: on the basement. Okay of the of the unit in order to avoid the transmission of the vibrations, and for the noise you should, if they that is important, if it if you are in other environment, you have to check the effort on the
19:37:740Michele De Carli: surrounding meetings. If you are inside of the room, or sorry if you are inside of the of the building, you have to check that. You have no transmission noise between your technical room and other.
19:52:25Michele De Carli: Okay, that's it. Now you have to check. Then the flow rate in each in
20:06:650Michele De Carli: in each room. Okay? So you have to. You have to check the flow rates for the supply and return. Okay, and then you have to.
20:24:540Michele De Carli: The 3rd step is to find to check the
20:28:560Michele De Carli: available space that you need. Okay, in order to add the primary and secondary branches of your docs. Okay
20:38:470Michele De Carli: in the step. Okay? So in the first, st in the design. So in the premier design, basically, you just have to check the space. Okay, that you have enough space to to run or to locate your, that's the main. And and basically
20:59:200Michele De Carli: and that's it. Now, if you go back to the final design, then you have to.
21:05:290Michele De Carli: Then you have to check again the flow rates. Okay, and based on the flow rates. You have to size the air terminal devices based on the air terminal devices. You have to then connect these air terminal devices to the secondary ducts. And then for the secondary ducts, you have to go to the primary ducts, and you have to then calculate
21:33:566Michele De Carli: section by section. Okay.
21:36:530Michele De Carli: the the localized pressure losses and the and the distributed losses. Okay, as you will see in a while.
21:47:440Michele De Carli: And then, of course, once you have determined. The pressure drops your secret.
21:56:270Michele De Carli: Then you have to select the firm.
21:58:780Michele De Carli: usually for the fun you have the you can see here. This is a picture of the farm. Okay, the farm. Here, you can see you have 2 available heads. Okay, so you have 2 available heads. One is the static head, and one is the total head, which is the static plus the kinetic or dynamic
22:23:620Michele De Carli: head.
22:24:930Michele De Carli: I suggest you to use the this.
22:29:630Michele De Carli: Okay head. Okay? So the static head. Okay?
22:35:760Michele De Carli: And that is because usually
22:38:80Michele De Carli: you don't know exactly how much of the dynamic had available. You can get it in in your case.
22:49:90Michele De Carli: But for sure you will have the static.
22:51:970Michele De Carli: Okay, and it is better to have more available had done
22:58:980Michele De Carli: less, as we will see in a while. Okay? So you can consider as conservative measuring the static head of your fund. Okay? And at the end and at the end. This is what you. So this is the fun. You can look at the at the right. Sorry the left hand side
23:29:395Michele De Carli: picture.
23:31:320Michele De Carli: So basically, you have calculated your losses. So you have calculated your, let's say, system period. Okay, so this is the system
23:41:731Michele De Carli: the system curve is this curve here the one you have calculated. And
23:51:110Michele De Carli: you have to deliver the flow rate.
23:55:00Michele De Carli: Okay, which is the flow rate, the design flow rate. And you have estimated the pressure. Okay, so basically, these are, this is the design, desire, design, condition. And of course, you have to select the fan which is able to provide the
24:16:876Michele De Carli: pressure drop that you have calculated, and the flow rate that you have estimated. So in that case the fun
24:26:400Michele De Carli: sure is perfectly matching your design. And this is okay. It's fine. It's perfect. Okay, but this is
24:37:50Michele De Carli: on the paper. Okay, so this is in autocad and paper in Excel, wherever okay, then you have to realize the plant. Okay, then you have to build up the plant. And sometimes
24:52:80Michele De Carli: very often, you don't really get what you what you have expected in the design phase. Why? Well, there are several issues. Okay. But they say that there are changes on the way. There might be some changes, so you might have some additional curves. You might go another in another.
25:14:180Michele De Carli: You might or you might have space that you estimated, or even you have some exfiltrations. Okay? So I want to remind you that the dots are merging are connected. Okay? And some
25:30:210Michele De Carli: air could could could blow outside. Okay, I told you that there are okay. There are methods for checking the tightness of the dots. Okay, while we are building up the the dots.
25:49:141Michele De Carli: but everything could happen so at the end, let's say, Oh.
25:56:710Michele De Carli: what you should consider so what should you do? Well, 1st of all, you should.
26:04:973Michele De Carli: Consider about 50, 20% greater flow rate expected. Okay? So
26:15:160Michele De Carli: how can you consider this? 1520%? Well, you should. You could consider it's likely higher
26:25:740Michele De Carli: localized pressure losses. For instance, okay, you could increase by 1015% the localized pressure losses with respect to the figures that we have seen before. Okay, so here you have the localized pressure losses. You could increase them a little bit in order to let's say, consider a conservative figure. Okay.
26:49:60Michele De Carli: and then, of course, you should.
26:54:680Michele De Carli: you should consider a document. Okay in each section. Okay of your plan. Let's say in each branch of your of your plan.
27:05:420Michele De Carli: Okay, wow. Well, let's see this chart here.
27:11:132Michele De Carli: Explain. So the case, one is the perfect match between the design conditions and the fund. Okay? So imagine that these are the design conditions. And you have selected the fund. Okay? So the fund you have selected is represented by this
27:33:500Michele De Carli: yellow line here. Okay, and the fund will provide you this rate and pressure.
27:44:270Michele De Carli: Okay, couple of parameters, head and prorate.
27:51:660Michele De Carli: So if this is the design. If this is the design and and desired condition. Okay, then, it's fine.
28:01:670Michele De Carli: Now you have 2 options.
28:04:762Michele De Carli: The 1st option is that you have.
28:09:240Michele De Carli: as in this case, I will. I will.
28:12:100Michele De Carli: Highlighting in orange. Okay at the end. Your real oh.
28:23:690Michele De Carli: distribution system. Okay, has greater pressure losses that you expect.
28:31:580Michele De Carli: Okay, so what can you do there?
28:36:600Michele De Carli: Nothing. You're done. Okay, there is no no way. Okay, because if you install a more powerful fan.
28:47:370Michele De Carli: then you might have 2 noise.
28:49:560Michele De Carli: because usually the fun is also related to the noise generation. So it might be that you have too noisy condition so basically you cannot do so much. Okay?
29:02:710Michele De Carli: Why, on the other hand, if you are, if you have overestimated the losses and you are in the blue line here. Okay.
29:15:00Michele De Carli: then it's fine. Okay? Because the
29:19:260Michele De Carli: you, you can either decide that you, it is okay. Even if you working with the greater rate. I want to remind you that today you can adjust also the speed of the fire. So voltage of your engine
29:39:490Michele De Carli: changing, you can adopt them. You can. You can go from the point. I don't know what. 3, I think to one. Okay. So by reducing the the
29:51:860Michele De Carli: 2 double plan, 1.1,
29:58:690Michele De Carli: if you have some. If you have some differences in the different.
30:05:800Michele De Carli: the different branches. Okay, you can adjust locally that
30:11:620Michele De Carli: by using the dampers, pay the dampers that we have seen. So by closing a little bit the dampers, you could have locally an increase of localized loss. Okay, which will reduce the
30:24:50Michele De Carli: fluoride in this.
30:26:350Michele De Carli: That's okay.
30:28:140Michele De Carli: And of course you will have then more airfare.
30:33:470Michele De Carli: So let's say that you can work on both the dampers and on the speed of the phone. Okay? So that is why it is recommended to work with
30:46:410Michele De Carli: 2030% of greater flow rate than the usual one. Because then, in real conditions. Okay, if you if you are in the if you have more flow rate than expected, you can adjust. Okay, the flow rate and you can. But you can balance the system. Okay by working on the dampers in case you can adjust the flow rate by the of course.
31:16:242Michele De Carli: Of course, you will have an increase of cost in the solution. Because so it's okay. You have to balance. If you want to, the risk on the on the flow rate. Okay? So of course, if you use 20% of better flow rate, then the cost also will be larger than, let's say, 10%.
31:44:430Michele De Carli: Understand? Okay, so this is risk and benefit. Okay? And that's it.
31:51:860Michele De Carli: All right.
31:53:910Michele De Carli: Okay, so I give the floor to
32:13:996Michele De Carli: okay, so I close the
32:22:870Michele De Carli: recording.