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00:00:430Marco Marigo: Nope, okay?
00:06:620Marco Marigo: Oh.
00:18:270Marco Marigo: excellent, not the mail.
00:23:930Marco Marigo: see?
00:29:740Marco Marigo: And
00:35:690Marco Marigo: simple message problem.
00:36:980Marco Marigo: Okay, okay? So my presentation will be.
00:47:770Marco Marigo: we have some concepts that maybe I have to share this.
01:06:60Marco Marigo: Okay?
01:08:140Marco Marigo: So we will see some
01:11:440Marco Marigo: some concepts in order to
01:15:620Marco Marigo: to understand how to make the project you have to carry out during this course. So we will take some concepts back from what Professor the call has already explained. We'll come back to some of these concepts, and then we will understand how to apply everything in order to
01:34:310Marco Marigo: to prepare the projects that you will have to to do
01:38:230Marco Marigo: so. You will have time until Easter in order to sign in one of the groups, I think we will have 12 groups to each group who will deliver a case study. I will show you at the end of the lecture today or next week. I don't know if I,
01:54:420Marco Marigo: for the time we have, which is the case. Study. How is the Pdf built and how we have to you?
02:01:770Marco Marigo: You can manage in preparing the project.
02:06:80Marco Marigo: We will take back some, go back to some concepts in particular, I will make a brief introduction all things that you already know. Then we see how to carry out the sizing of the system. So we will. Take all the things you have
02:22:00Marco Marigo: taught during the last 4 lectures, and we will summarize them and see which are the passages you have to create out, 1st of all, by defining the design flow rate of your unit of full air system, and then to decide the ducts and the vents that are the 2 topics
02:40:400Marco Marigo: on which the project is based, and at the end the calculation of the pressure losses, the output of your project will be the calculation of the localized and continuous pressure drop for your specific case study
03:00:386Marco Marigo: in this presentation we will also see an example that is taken by an European standard. That is the sizing of a residential case. Study your case. Study in the project will be bigger. It will be an office of more or less one or 2,000 m² floor area. In this case we see a residential case study so that we can talk about it
03:27:790Marco Marigo: easily, because it's it's smaller.
03:31:250Marco Marigo: I will present you the tool, and at the end of the presentation we will talk about your assignment, and which are the requirements for the record.
03:39:930Marco Marigo: So the I will go fast. This slide. You already know that there are 2 kinds of air system, the full air systems and the primary system, and the primary system is something like the one we have now. In this room, for example, they are coupled usually with the motor system
04:05:740Marco Marigo: working in heating or cooling, and the sensible load, and the latent load is provided by the fun coils in the primary air systems, while the change of the indoor air, so the inlet of fresh air is provided by the air system.
04:22:310Marco Marigo: the Ashrai standards, and all the committees cause this system primary care systems. And are
04:35:920Marco Marigo: we can say the the alternative is to use a fuller system. If we had air system, we wouldn't have the phone calls, radiators and so on. But we would only have one primary air system. Sorry one fuller system with the higher flow rate, of course, but in that case the fuller system would provide both of the fresh air for
05:00:650Marco Marigo: diluting the pollutants and the heating and cooling loads through a certain rate and a certain event or supply temperature.
05:12:560Marco Marigo: We have advantages and disadvantages for both these systems. You know that in this way, with the primary system and the water system. We must provide 2 kinds of different systems to
05:27:910Marco Marigo: to heat up and to treat the beer in one room, so each environment must have 2 systems
05:36:940Marco Marigo: in a folder system. It is much easier because you just have to set one system that provided both the requirement.
05:45:170Marco Marigo: This is the advantage of of fuller systems. Of course these disadvantages are related to the higher noise, to the higher flow rate that you must treat, and so also to the higher volumes that are required for such a system. So we have advantage advantages for each kind of concept. These are 2
06:11:720Marco Marigo: different concepts for installing a system in a room. It depends on also on the habit.
06:21:860Marco Marigo: For example, here in Europe, usually we use cooler system for commercial building for offices for big rooms for big buildings, and usually our houses are adopted with the water systems, and sometimes especially newer ones. We have the primary systems. But this is something that depends on the
06:45:70Marco Marigo: on the years and on how the engineering practice is developing in Northern America. Usually you have fuller system also, almost everywhere, is much more diffused than here. For example, this also in residential buildings. But this is something that depends actually, what you must know is that there are 2 different concepts. And these are the 2 concepts.
07:10:240Marco Marigo: If we move to energy system, we can see that there are different components of energy system. The core is directly unit
07:22:27Marco Marigo: this structure is almost valid for both
07:25:840Marco Marigo: full air and primary air systems, because always you must provide a machine.
07:35:270Marco Marigo: That is a case which, where all the components are installed. So you decide you have the filters. You have the fun. You have the the coins, eating and pulling coils. You have the humidifier it can be. It depends on what you have to do with the air, how you have to treat this here. So the air and the unit is the core of your system.
07:58:470Marco Marigo: And this unit, in order to change, transform the air, must be connected with the generation system. The generation system produces hot or cold water. So you will have to couple this unit, especially in case of full air system with a water tank, a hot water tank and a cold water tank, because you must provide both heating and cooling load in case of full air system.
08:30:580Marco Marigo: So that is the connection. You will have this machine connect to the water side. And if you look at your side you will have some ducting that will allow you to
08:43:380Marco Marigo: Take air from the outdoor.
08:46:130Marco Marigo: You will have to treat this air, you already know how, and then you will have an air distribution system with the ducts that deliver the air from the air handling unit after the treatment to each room that you must provide, because air must be provided to each room in the quantity we want in order to fulfill all the requirements
09:10:460Marco Marigo: at the end of our air distribution system, when there are planning and ducts, and so on. We will have the vents that are the connection, would we say, between the room, for example, that vent is the connection between the duct that is delivering the air and the room itself when the where the air is
09:30:270Marco Marigo: distributed. So these are the 4 main components. In our case your report will be focusing on the distribution air system with the calculation of the losses and on the choice of the air terminal unit. So you will have to choose the band.
09:49:480Marco Marigo: This is a very easy schematic slide that you have already seen. So here you can see the main concepts you take here from the outside. This is just the supply
10:06:510Marco Marigo: supply, doctor. We will have both the supply and the exhaust and also the recirculation, doctor, but, as you can see, you take care from the outdoor you treat inside the unit, then you have the fund that pushes the air towards each single room, and then you will have a main doctor, and then, like
10:28:00Marco Marigo: some branches, we have a reduction in section, as the different branches are dividing themselves, so the main duct will divide into 2 secondary ducts or more. I don't know. This depends on the layout of our case study, and then we have the final branches that you can see here with their terminal device that is adopted at the end. As you can see.
10:53:560Marco Marigo: one of the most important concepts is that in order to keep the system balanced, we have to reduce the section of the ducting as the flow rate is reducing
11:12:420Marco Marigo: through the through through the ducting. So, as the duct length increases, so in this place, in this part we will have constant flow rate, and constant section, then the flow rate will split into parts, and we will have that the section of the ducting is reducing in order to keep a velocity that is enough in order for the air to reach
11:36:460Marco Marigo: the final point and to be introduced in the room. And so the section of the ducting will be reducing as the duct is proceeding.
11:52:560Marco Marigo: What does it mean to size in a system? We will have some input and some output.
11:59:206Marco Marigo: What should we already know about our case study, we must, we must already know the end user of the building. So if it is a commercial one, so on, this is the 1st input, of our sizing process. The second input is the Hvac configuration. So if we are deciding to install a full air for a primary system in our case, we are talking about the system.
12:27:530Marco Marigo: The 3rd point that we must know is the thermal requirements and the indoor quality we must provide to the room in order to calculate the flow rate that is required. And the last point we must know the buildings. So we need the detailed layout of the building, because we have to draw
12:48:370Marco Marigo: the different adapting that are connecting. So decide where to put the air and the unit, and then draw the different ducting see which is the net, we could say, that is, delivering the air from our end until each room that we must reach. So the output
13:08:172Marco Marigo: are the duct, length, and the design design, not only the length of the duck, but also the section, the shape, and so on.
13:18:300Marco Marigo: and the output. The final output is the choice of the machine of the system
13:23:170Marco Marigo: for this project. You won't have to decide the machine, but we will stop at the previous step. We will see later. Which is this previous step.
13:36:08Marco Marigo: If I'm going too fast or too slow, please tell me. And then I adjust, because I don't know what you have already seen during the lecture.
13:44:655Marco Marigo: Just a last thing I want to to say
13:50:530Marco Marigo: is that differently from this kind of system I just want to mention. I don't know if you have
14:02:290Marco Marigo: already talked about it. You can see that this is just one approach for the ducting. So you have a main duct, and then the split into ducts.
14:16:110Marco Marigo: and so on.
14:18:170Marco Marigo: And then
14:20:80Marco Marigo: okay, and then like this, and so on. This is one approach. If we are talking, and this is the approach we will use for our system and the fuller system. The tool that I will show you is made to size this kind of system. But if we are talking about a smaller
14:39:37Marco Marigo: system, primary air system, residential, so smaller kinds of air and unit, there is another possibility of sizing just for you to know. So sometimes you have the machine
14:54:30Marco Marigo: as the outlet of the machine. You have a plan. Okay? And then from the plane you have different that are reaching the different rooms. Okay, this is something more, like a spider. Okay, all these doctors usually have more or less the same size. This is a much
15:16:170Marco Marigo: easier way of sizing in your system, but can be done for flow rates that are much smaller than
15:25:350Marco Marigo: these ones. Okay? So usually here, the full air system is sized in this way. If we have primary system, we have just one main doctor that goes outside from the machine to a plenum. A plenum is a box. Okay, as you have seen, and from that plenum there are maybe 2, 3, 4, 5, 10 different ducts that are exiting, and each duct will go
15:51:490Marco Marigo: to a specific room and to a specific event.
15:55:610Marco Marigo: So this is the second approach. We won't enter into the detail. We will see only this, but I wanted to mention that maybe residential buildings you will have to face a different kind of sizing of the dot.
16:08:430Marco Marigo: But okay, in our project we will neglect the ventilation.
16:22:760Marco Marigo: concept. So I know that you have talked about the displacement of ventilation. We know that, for example, the displacement of ventilation is made through some diffusers that are placing the bottom side of the room, and that instruction is on the ceiling, but in this case we will simplify the project, because
16:42:790Marco Marigo: otherwise in this way we will have some additional crucial points to the velocity of the airplane. And so we will consider that we are talking about mixing ventilation procedure. Okay? So the air will be supplied from the ceiling.
17:02:130Marco Marigo: Okay.
17:03:870Marco Marigo: so let's see the procedure you will have to face, and then let's enter into each single point.
17:15:869Marco Marigo: The point one is that you must provide. You must calculate the thermal loss, the thermal loads of the building for the heating and the cooling system.
17:26:980Marco Marigo: and in parallel you must complete the requirements in terms of interactivity.
17:33:310Marco Marigo: So you will have 3 different inputs. The one is the cooling load. The second one is the heating load. The thermal one is the mass of air, the volume, flow, rate of air, that the indoors
17:51:290Marco Marigo: we will neglect the part of the calculation of heating load, because you have already done, and in the project. In the report you will receive the heating load and the cooling load of your building. Okay, I will show you the Pdf. At the end of the Pdf, you will see cooling load equal to X, what? And heating load equal to y equals. Okay? So you will already have this. Input, so you don't have to calculate.
18:19:870Marco Marigo: Then, once you have calculated this heating reload, you must calculate the air flow rate to supply to each environment. This will be obtained from the maximum value between the flow rate associated to the heating node and flow rate associated to the cooling load and the flow rate for the indoor air quality environment. So the design value
18:48:830Marco Marigo: will be the maximum of the mass for heating the mass for cooling and the mass for air quality.
18:59:440Marco Marigo: I had not the space. And I went. Okay.
19:03:570Marco Marigo: so we will have to choose which is the maximum of these 3 values.
19:09:490Marco Marigo: And we've had to set the design floor rate as the maximum of these 3.
19:18:680Marco Marigo: And why are we doing this? This is very important.
19:23:300Marco Marigo: because in every moment of the year
19:27:310Marco Marigo: we must be sure that our system is able to provide heating, cooling, and indoor quality.
19:34:580Marco Marigo: so we can't go below this level. Otherwise, if I'm not fulfilling, if I don't consider this, for example, the heating the the flow rate for heating. There is the possibility that maybe the 3.rd No, because usually
19:50:820Marco Marigo: in the year I can't fulfill the heating loader, so my temperature inside the building is decreasing. So I must take into consideration all these 3 components and the mass I will have to deliver is the maximum.
20:05:520Marco Marigo: The design value is the maximum between these 3 at the end. This
20:12:750Marco Marigo: will be distributed in all the rooms, so I will have the mass for each room, the mass rate for each room.
20:22:310Marco Marigo: and once I know which is the value of your rate for each room, I can set the events. So I must take the catalog for the events and solve. Okay, here, this room. I must provide them. I don't know.
20:36:440Marco Marigo: 1,000 cubic meters per hour. Now I will design the vents. I put 3 vents for the supply in this case 1, 2, and 3, and I will decide which is the flow rate for each one, I said, which is the position of each event. And then I think,
20:55:690Marco Marigo: I take these places. Okay, this room that is returned. For example, okay, and I have that, I have 3 distribution point and 3 supply beds.
21:09:760Marco Marigo: Once I know this point for each room of my building. I will have to dual
21:17:490Marco Marigo: the doctor. I would have 3 dots here that are connecting the vans to the secondary doctor. Maybe if I have another room here.
21:31:80Marco Marigo: so I have 2 rooms like this. For example, I will have that both.
21:40:370Marco Marigo: I'm the same, and so I will draw, I will make a little sketch of the distribution system of air.
21:47:260Marco Marigo: Yeah, maybe I will have one, I don't know. And here I have the parent unit. So I can have like this kind of distribution system here. I will have one main doctor.
21:59:620Marco Marigo: 2 secondary branches, one that goes in this side, the other that goes on this side, and so on, and then the final branch that links all the bands.
22:09:840Marco Marigo: and so on.
22:17:180Marco Marigo: We have made a little sketch of our distribution system, and then we have to determine the airflow in each part of the system. Once I know that here I have the total amount. That is, I don't know 1,000
22:34:10Marco Marigo: cubic meters per hour. I know that I must divide into 3, so I will have that each.
22:41:550Marco Marigo: No, so each bank must provide 323
22:46:710Marco Marigo: cubic meters per hour. And so I will have that I must know in each data.
22:53:60Marco Marigo: okay, in each part of the ducting. So here I will have 3 3 until this point. Then here I have the connection, maybe also here, 6, 6, 6, and so on, and so in each part of the duct, I must know which is the flow rate that I have to provide.
23:16:850Marco Marigo: So once I know in each part of the ducting, which is the associated flu rate. I will try to decide the size of the duct.
23:29:880Marco Marigo: I will fix the velocity inside your doctor for
23:33:280Marco Marigo: noise level, and then I will choose the shape of my ducting.
23:42:530Marco Marigo: Once I have made this preliminary design, I can calculate the pressure losses for all one solution system.
23:51:640Marco Marigo: This is the procedure very fast.
23:59:270Marco Marigo: Let's go to the point number one.
24:06:210Marco Marigo: The point number one was definition of the flow
24:11:640Marco Marigo: for cooling, heating, and indoor quality requirements
24:21:780Marco Marigo: in order to define the term
24:25:710Marco Marigo: according to the indoors. What is the requirement?
24:31:850Marco Marigo: Okay.
24:36:790Marco Marigo: the design flow is the maximum between the heating, pulling and in the quality.
24:49:240Marco Marigo: In order to set
24:52:340Marco Marigo: this term I would have to see which is the standard. The standard is always the same. 16,
25:01:220Marco Marigo: 7, 9, 8, 5, 1.
25:06:880Marco Marigo: And how is the sound built? You may already know, I think.
25:11:970Marco Marigo: Have you explained the the standard? The classes?
25:16:280Marco Marigo: Okay, okay, so there are. The standard says that there are 4 different categories that you can see there.
25:28:780Marco Marigo: The 4 different categories defines which is the indoor quality level that you reach.
25:37:990Marco Marigo: So if I want them to reach a category one, I must provide a particular level of of air.
25:51:350Marco Marigo: Then
25:53:20Marco Marigo: the the standards give the category number 2 with a medium level, the category number 3 with a moderate level, and the 4th category that is a low value of indoor quality.
26:08:167Marco Marigo: There is just one strict rule, so there are. You are not obliged. So you're not forced to stay in one category, respect to the other. The only strict rule that you must fulfill is that the minimum flow rate in every room should never go below 4 meters per person per second.
26:35:280Marco Marigo: That is a limit that you must always fulfill when you are sizing a a florator
26:44:880Marco Marigo: to fulfill the indoor quality requirements. You can't go below this limit. You see, this is a limited that the standards booked, and when you size system especially for public building, you can't go below this limit.
27:03:930Marco Marigo: So once you have selected the level, the category that you want to reach.
27:11:280Marco Marigo: Let's see if I didn't do that.
27:15:127Marco Marigo: I don't remember by heart which are the levels. But you will see you will go to the standard.
27:21:360Marco Marigo: and then you will see that, for example, Category One.
27:27:340Marco Marigo: I think he's 1 between one and 1.2 air changes per hour. But I'm not sure actually.
27:37:461Marco Marigo: the second should be 0 0 point 7,
27:41:100Marco Marigo: and the 3rd is 0 point 4. Maybe I don't know. But if you want later, we can check and see which are this value. So for each category, the standard says, Okay, do you want to stay in category 2. So medium average value, you have to choose 0 point 7 air changes per hour. So from this value to this per hour, you convert to cubic meters per hour, or
28:07:280Marco Marigo: meters per second, and then you will have this value.
28:20:650Marco Marigo: So this is the sizing according to the indoor quality requirement.
28:29:490Marco Marigo: What you will do is that you make a list of all the rooms?
28:36:570Marco Marigo: Okay?
28:37:730Marco Marigo: So I would have a you know
28:41:20Marco Marigo: room one room, 2, room, 3,
28:45:100Marco Marigo: 2, 4, and so on. For each room you have the lower email.
28:55:230Marco Marigo: You have the volume of the room itself, and then you can create for each room
29:03:440Marco Marigo: the requirement of related to the indoor quality. Okay, if you want to reach Category 2, let's make deposit is 0 7. You will have to make the r. 1,
29:19:720Marco Marigo: and here you will receive, which is in cubic meters. However, okay.
29:35:670Marco Marigo: the flow rate required in terms of indoor airport.
29:42:50Marco Marigo: and we have calculated for each room. This is very important. Each room, the loss
29:48:350Marco Marigo: associated muscular rate associated to the indoor quality.
29:53:330Marco Marigo: Second point.
29:55:890Marco Marigo: once we have decided this, we must also calculate the mass flow rate associated to the heating and cooling load.
30:03:900Marco Marigo: We have told, I have told you, that you already have the heating and cooling load
30:10:330Marco Marigo: provided in the Pdf. For your project. But the question is, if I have the flow rate sorry the node for heating, which is the connection with the air that must be provided heating. So I need to check this connection because I have this in kilo calories per hour
30:38:880Marco Marigo: much better, but which is the mass flow rate associated to that
30:44:770Marco Marigo: I have to do it in 3 steps.
30:49:770Marco Marigo: The 1st one is to define the indoor conditions.
30:59:340Marco Marigo: You will see you can see in the table which are in the condition. So
31:03:120Marco Marigo: let's start from the heating load. For example, I will decide that I will have to obtain inside the room. Okay.
31:11:790Marco Marigo: the indoor temperature to heating
31:17:970Marco Marigo: this is equal to 20 degrees, for example.
31:27:830Marco Marigo: And so
31:36:130Marco Marigo: by fixing the Delta T between the supply and the environment. That is this one.
31:46:490Marco Marigo: Okay, this is a rule that we give you. Usually the difference between the temperature of the supply, air and air of the environment should never go below. Sorry above the 20 Celsius degrees. Why we do. We have this limit in order to avoid the stratification and to avoid putting hair that is too hot inside the room. So here, if I have
32:14:280Marco Marigo: chosen 20 census degree for the environment for the set point of my environment, my supplier can't go
32:25:410Marco Marigo: should be lower, actually instead of 14.
32:30:00Marco Marigo: Okay.
32:32:560Marco Marigo: so this is a limited but actually what you can do if you don't have the possibility of producing this kind of area. You can also decide that it is certified. For example.
32:43:460Marco Marigo: okay, it's up to you to choose.
32:47:450Marco Marigo: Which is this Delta. T. The important point is that you stay in this range between 12 and 20.
32:55:700Marco Marigo: Once you have decided the supplier, you can calculate the no, because, as we are total
33:17:20Marco Marigo: about this equation. That is the equation of the heating loads of the heating load. All the heating load must be fulfilled by
33:28:660Marco Marigo: in a flow, and the temperature
33:33:730Marco Marigo: supply temperature that you have decided here.
33:37:610Marco Marigo: And in this way beyond is the volume flow rate, or your eating load?
33:44:890Marco Marigo: Is it clear this procedure?
33:47:320Marco Marigo: If for someone it's not clear, please write it down and ask.
33:51:400Marco Marigo: otherwise, how do we go on?
33:54:80Marco Marigo: Clear for everyone?
33:55:520Marco Marigo: Okay.
33:59:80Marco Marigo: the same. You must provide with cooling load, pay attention that the the restriction in cooling is higher, because it is
34:11:50Marco Marigo: much more risky to have some draft risk in this case. So the Delta T between the environment and the supply
34:22:179Marco Marigo: should not go below 8 Celsius degree, and not above 12 Celsius degrees.
34:33:380Marco Marigo: So when you are deciding that the indoor conditioning. Pooling is, for example, 26,
34:40:460Marco Marigo: that is this one. In summer we have set it for the indoor condition. 26. You can't go below in this case 14 for the supply. So the limit to the air temperature and the supply of our system is 14.
35:00:420Marco Marigo: Otherwise it's risky for the draft.
35:03:450Marco Marigo: 1516 is bad.
35:06:790Marco Marigo: So once you have done like this, you have calculated the 3 values, the mass
35:12:550Marco Marigo: in terms of indoor quality.
35:20:600Marco Marigo: the volume associated with the heating. But okay, let's pull it to the same name, the volume for heating
35:31:620Marco Marigo: and for you. We are always talking in this case about just cubic meters per Harvard.
35:43:980Marco Marigo: So you have got 83 values.
35:46:810Marco Marigo: Oh.
35:50:530Marco Marigo: volume, flow rate to be delivered to the room, and, as we have seen, which is the value we must choose
35:59:550Marco Marigo: is the maximum between these 3 nodes, and this becomes the nominal
36:07:930Marco Marigo: volume, volumetric flow rate for your air handling unit.
36:16:790Marco Marigo: or, better, the volume that
36:19:360Marco Marigo: this value is the sum of all the rooms of this. We are thinking about each room singularly okay.
36:28:140Marco Marigo: but the nominal sign value is the total
36:35:590Marco Marigo: that you can find here. So the maximum of these values.
36:49:750Marco Marigo: And then we we will face another problem.
37:01:840Marco Marigo: So let's imagine that for example.
37:12:740Marco Marigo: I will go to the example. That is, I think, clearer.
37:18:850Marco Marigo: Let's imagine we are in situation like this. So we have 3 rooms.
37:23:430Marco Marigo: I must provide for each loop. I have related
37:28:270Marco Marigo: the design mode. That is this one.
37:33:00Marco Marigo: Okay, here, here and here.
37:36:600Marco Marigo: And I have also calculated the indoor air quality requirements. So these 3 flow rates.
37:45:210Marco Marigo: So in order to fulfill in this case, we were talking about
37:49:250Marco Marigo: summer condition, as you can see, in order to keep inside these 26 Celsius degrees. I will have to provide one kilowatt, almost 2 1.8 kilowatt, 5 kilowatt here, and 7.5 kilowatt here. Okay, and I calculated that with the supply at 16 Celsius degrees that I've chosen.
38:11:430Marco Marigo: As I explained you before, I have to provided these 3 design flow rates, and for each one.
38:19:870Marco Marigo: I have seen that I must provide this value for the indoor quality requirements.
38:26:380Marco Marigo: so I calculate which is for each room. The ratio between the indoor quality
38:37:70Marco Marigo: flow rate and the total flow rate. And I see that I have 0 point 5 4 0 point 3 33 and 0 point 3 6,
38:50:630Marco Marigo: which is the programmer.
38:53:290Marco Marigo: The problem is that the machine is just one.
38:57:900Marco Marigo: So if I found him.
39:07:260Marco Marigo: if I must provide them
39:15:25Marco Marigo: this indoor air quality flow rate. How can I do it?
39:21:950Marco Marigo: So I need to
39:29:100Marco Marigo: take my hair and the unit that is this one.
39:32:280Marco Marigo: I have to link them here, and it's unicorn
39:36:30Marco Marigo: to the 3 rooms. Let's imagine they are like this.
39:42:610Marco Marigo: Oh, no, okay.
39:45:00Marco Marigo: These are the 3. Also, in customer connection is better. Okay, I have my yearly unit that must provide
39:54:710Marco Marigo: their flow to these 3 rooms. So here, here and here.
40:04:610Marco Marigo: I can decide to work with the only fresh air. So at each time step I take
40:12:210Marco Marigo: the full amount of fear.
40:14:480Marco Marigo: the the sum of these 3 values, so 2,002, 1,005 and 0 point 5,000, and so on. 500.
40:23:820Marco Marigo: The total design no, and treat it
40:35:40Marco Marigo: at the end. I will have at 6 16 degrees, and deliver at each room and design one and design 2
40:46:530Marco Marigo: haven't done good talking to you.
40:49:490Marco Marigo: But which is the problem of this approach is that I must at each moment treat a very high volume of air.
41:00:320Marco Marigo: So what should I do to reduce the power, the heating capacity of this system? Because if I have to take all this volume of air. I need very, very high power. So pulling, noise and heating always very high, and at each time step work with a high amount of air.
41:18:740Marco Marigo: If I want to reduce this, I can recirculate. So take some air from each room
41:29:540Marco Marigo: and call it back in the air handling unit.
41:36:90Marco Marigo: This here that is already at was already treated before is mixed up.
41:44:890Marco Marigo: We took the New year.
41:51:930Marco Marigo: So here
41:53:700Marco Marigo: it is not needed that I take all the total amount of air, the total amount of air total design.
42:06:530Marco Marigo: will be in this part, so I will have always the same total design flow. But here I will have 3.
42:15:790Marco Marigo: The circulation path.
42:18:870Marco Marigo: Okay, and here the flow will be the total design.
42:23:200Marco Marigo: Mine was one plus r, 2 plus r. 2.
42:30:300Marco Marigo: So I will have that I will.
42:33:20Marco Marigo: Lower down is
42:35:560Marco Marigo: air that is very hot because comes from the outside. I will lower this amount of air through recirculating some air and pre-mixing before treating. So I will have that here in the unit here I will have the coolies, for example, the heating, cooling boys, and so on, in this case cooling because we are in cooling.
42:56:580Marco Marigo: pulling, and post eating, and they will pre treated here through a mixing with the hair that is not at 16, but will be at 26, because inside here we have 26, more or less.
43:10:660Marco Marigo: Okay. So this year 26 is premium year at 35.
43:21:670Marco Marigo: So let's come back to our previous problem.
43:26:150Marco Marigo: If I have that room, one
43:29:590Marco Marigo: must have the 54% of new air.
43:34:570Marco Marigo: So the mass, this room one must have had one.
43:43:770Marco Marigo: That is, 0 point 54 M. 2 and 0 point 2 3
43:55:870Marco Marigo: and M. 3 0 point 36.
44:02:390Marco Marigo: It means that the ratio of the newer that is, this one.
44:16:70Marco Marigo: the ratio between this new air that comes here and the total, that is, this one
44:24:690Marco Marigo: is required is 55%, 33 and 36. But I have only one machine to provide this.
44:34:460Marco Marigo: So all the mixing happens here. So what I need to do is to move, change
44:44:190Marco Marigo: M. 2 and M. 3, in order to have for each environment the same racial 0 point 54.
45:00:80Marco Marigo: Why? Because the this M. Value will be the same for everyone. And so if I lower down
45:09:240Marco Marigo: this ratio, for example, to 0 point 33
45:12:340Marco Marigo: in this room. I won't have enough air for fulfilling these order quality requirements.
45:19:220Marco Marigo: so I will have to increase for all this value the M. Value to the maximum one.
45:28:230Marco Marigo: And so what you should do is to calculate the M value for each environment. Take the maximum one and recalculate the
45:39:670Marco Marigo: flow associated with indoor quality requirements in all the rooms that have an M value lower than the maximum.
45:48:120Marco Marigo: Excuse me, yeah.
45:49:570Marco Marigo: The project. How do we kind of how do we get going?
45:53:660Marco Marigo: 550, 59,250.
46:00:730Marco Marigo: So you're talking about this, this, and this
46:07:830Marco Marigo: is the maximum between this, this and this.
46:14:620Marco Marigo: usually or always, these 2 values are higher than this one.
46:21:680Marco Marigo: so it can be. There is the possibility that you have these equal to this. And so m. 1. There is the possibility. But
46:33:30Marco Marigo: it's very, very something that doesn't happen easily.
46:39:790Marco Marigo: because it means that you have a cooling load and a heating load that is very, very, very, very low.
46:45:70Marco Marigo: and is below the requirements for indoor quality. That is something that usually doesn't happen
46:58:810Marco Marigo: any other question.
47:00:850Marco Marigo: I don't know if I was clear enough. This process is quite challenging to understand.
47:06:560Marco Marigo: Yes, why we selected just the maximum.
47:23:790Marco Marigo: and then we have to read the fresh air flow rate.
47:33:280Marco Marigo: If you calculate, then 800, divided by 1,500, we are reaching the M. 2 equal to m. 1.
47:42:290Marco Marigo: Okay, so I will have to scale up all and balance.
47:55:820Marco Marigo: which is the problem in this case. But it's something that we have to deal with.
48:03:90Marco Marigo: That the volume of total air
48:06:360Marco Marigo: require the 4 indoor quality requirements. That is the sum between this, this and this moves from 1,600 to 2,300. So we have an increase
48:19:560Marco Marigo: in the volume flow rate due to the indoor quality requirements in order to keep the M. Constant. So we are
48:26:560Marco Marigo: increasing the value of neural requirements more than the standard requires. But this is something that we can't avoid, because we can't treat every room. Similarly, we have just one machine, and the recipulation must be done inside the machine, so
48:42:90Marco Marigo: I will have an increase in the indoor quality requirement. The indoor quality requirement is air that comes from the outside, so very hot in summer, very cold in winter, and I will need an additional power, so I will have to size up the system in order to be able to fulfill also to cool down or heat up this additional air that was added because of this point
49:09:500Marco Marigo: any other question on this.
49:14:260Marco Marigo: Okay, if I was not clear, you can ask me later or in the next days, it's not a problem.
49:21:800Marco Marigo: Let's see an example.
49:24:110Marco Marigo: This is what
49:25:490Marco Marigo: I have already shown you before. So it's just a specific case. This is a residential building.
49:34:240Marco Marigo: This case is presented in the standard 16 9, 8
49:40:910Marco Marigo: 67. I need I don't remember in which part I wrote in the next slide.
49:48:680Marco Marigo: but, as you can see, we have a residential apartment.
49:52:800Marco Marigo: 2 bedroom and hallway one bathroom, 2 bathrooms, actually one office kitchen and living room for each
50:03:660Marco Marigo: room. You have a floor area.
50:06:430Marco Marigo: And you have the specific volume
50:10:940Marco Marigo: in this case for simplicity, because we have no time to see detailed analysis. But we are just sizing the supply
50:21:810Marco Marigo: path, and we are just making the calculation
50:26:740Marco Marigo: for the indoor quality flow rate. So I'm just showing you how it goes with the indoor quality flow rate.
50:38:456Marco Marigo: and this is something that we will come back to later. It is very important that you don't forget to verify. Their flow must cost.
50:48:640Marco Marigo: Now we will see what it means in the report of the last year. This was the main mistake. Almost half of the students were wrong with the balances of the air mass flow rate.
51:00:920Marco Marigo: Remember, as I showed you here, this
51:07:880Marco Marigo: plus the recipulation, must provide the total design flow. There can't be an inlet and an outlet that don't reach the balance.
51:21:250Marco Marigo: Later, we will see.
51:24:620Marco Marigo: Okay, so this is the table. I was completely wrong with their changes per hour.
51:31:120Marco Marigo: They are much lower than I remember. But that's okay. So and
51:40:200Marco Marigo: we are considering now that we have no loads.
51:44:490Marco Marigo: So the design load R equal to 0. In this case
51:54:480Marco Marigo: we are considering that these are 0, so
52:01:60Marco Marigo: in this case the design value will be equal to
52:09:950Marco Marigo: the flow of design will be equal to the flow relating to the. It's just
52:16:340Marco Marigo: a very fast example. Then I will see if next time is better to.
52:24:670Marco Marigo: Are we finishing a 4? Right?
52:27:470Marco Marigo: Okay, management fees.
52:31:963Marco Marigo: Okay? So just then we will start once more from this case study on Monday. So
52:40:610Marco Marigo: I am selecting for each point of the table. So for each level.
52:46:930Marco Marigo: 0 point 7 0 point 6 0 point 5 and 0 point 4, which are the associated
52:54:740Marco Marigo: flow rates in cubic meters per hour related to this level of indoor quality. So
53:05:110Marco Marigo: these are made for the whole building.
53:10:750Marco Marigo: Okay? So you take the floor area off
53:17:516Marco Marigo: your your building. You multiply by the hate, the average height of the building, you obtain the volume. Okay? And then by the volume you calculate, which are which are these
53:29:850Marco Marigo: fluorate according to indoor air quality, and this becomes
53:34:470Marco Marigo: the flow rate the design flow rate. You can see that we have chosen a level 2 that is 1, 138. We have rounded to 140
53:46:940Marco Marigo: what we are doing, and then I leave you.
53:52:50Marco Marigo: Pay attention, as you can see, we are not providing air to all the rooms.
53:59:510Marco Marigo: We will see that the sizing procedure ask us to provide air to the clean room.
54:19:220Marco Marigo: clean room that are living rooms, office bedrooms.
54:27:330Marco Marigo: and so on, and extract air
54:34:680Marco Marigo: from dirty rooms, boxes
54:44:370Marco Marigo: closing excellent.
54:48:780Marco Marigo: So we will supply air to some rooms and extract from others, but the total volume of air
54:59:970Marco Marigo: must be fulfilled. So if I decide that level 2,
55:04:620Marco Marigo: I will provide only in clean rooms. I will extract from the others in order to create some flows inside my rooms.
55:15:590Marco Marigo: but I will have to be sure that my total flow rate is fulfilling the indoor quality level that I'm fixing.
55:27:250Marco Marigo: We will come back to this point, and we start from this next time. But right now I'm just mentioning. So we take once more this example, and explain in a slower way, and much better
55:39:530Marco Marigo: see you on Monday.