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00:01:350Jacopo Vivian: Okay, cool.
00:05:20Jacopo Vivian: Today we finish the hydronomic part. I hope we will speak about. We have.
00:14:730Jacopo Vivian: I haven't spoken for 2 lectures about the design of hydronic systems.
00:23:180Jacopo Vivian: And now I will talk about the operation. So once you design the system.
00:31:910Jacopo Vivian: we also need the system to work properly, which means basically portal hydraulic systems.
00:44:140Jacopo Vivian: 2 things.
00:45:910Jacopo Vivian: And I want to be very clear on this definition.
00:50:580Jacopo Vivian: So because sometimes we talk about the operation.
01:00:590Jacopo Vivian: too.
01:03:10Jacopo Vivian: Okay, okay, we talked about the operation of Hvac systems
01:11:310Jacopo Vivian: with some terms, and we don't know what they really mean.
01:16:850Jacopo Vivian: So I want you to focus on this definition.
01:24:870Jacopo Vivian: When we talk about regulation, we talk about adjusting the temperature or flow in a hydronic circuit
01:34:40Jacopo Vivian: so that users are satisfied in different operating conditions.
01:40:274Jacopo Vivian: What we are most interested in is partial load, of course, also a design loaded, but if the system is designed properly, you should
01:52:250Jacopo Vivian: always be able to provide that
01:54:860Jacopo Vivian: they hit the correct hitting or putting log into the meeting.
02:02:980Jacopo Vivian: when the energy needs of the building is lower than the design load. You need to adjust temperatures and flow rates accordingly. Okay, so this is the regulation. So as you, as you understand that we are talking about controlling the Hvac system properly.
02:28:780Jacopo Vivian: The second. The second term that I want to introduce now is balancing.
02:35:920Jacopo Vivian: Balancing is not the same as a regulation, because balancing
02:43:647Jacopo Vivian: at least, this is what we agreed here in this course. Okay, maybe if you go out, you can also find that other interpretation of these words. But in this course, balancing is
02:59:360Jacopo Vivian: adjusting pressure and flow rates so that the flow rate is evenly distributed in the meeting.
03:07:510Jacopo Vivian: Mainly we are talking about bouncing at full load. Okay, so
03:15:750Jacopo Vivian: what is the difference between the 2 things?
03:18:890Jacopo Vivian: The regulation refers to partial load operation of a building and balancing means that at design condition.
03:31:220Jacopo Vivian: If one part of the building is needs to be supplied, 10 kilowatts and another part 12 kilowatts.
03:40:710Jacopo Vivian: If the system is well balanced, if the 1st part received exactly that 10 kilowatt and the second part exactly 12.
03:51:520Jacopo Vivian: Okay, so I'm not talking, of course. Then also at partial load, you have the same problem.
04:00:610Jacopo Vivian: but with dancing. Normally, if it works at full load, it should work properly also at the partial load.
04:10:520Jacopo Vivian: So I hope the difference between these 2 things is clear, because from now on I will not.
04:18:459Jacopo Vivian: I don't know.
04:20:480Jacopo Vivian: Of course I will repeat if you if you ask for it, but I will give these 2 definitions for granted from now on. Okay, so regulation is more about control and balancing is more about
04:34:850Jacopo Vivian: evenly distributing the heat or the cooling within the building.
04:41:200Jacopo Vivian: So we need to introduce some metrics to talk about regulation. The 1st metric is maybe, if one of the most important is the flow factor of vows. Okay, so voucher, are the components that are used to achieve both a well regulated and a well balanced
05:04:660Jacopo Vivian: hydraulic system, and the characteristic of mobile is called flow factor.
05:13:00Jacopo Vivian: What is this flow factor? It is a flow rated. So it's my measured in cubic meter per hour
05:20:990Jacopo Vivian: across the world at specific conditions.
05:24:660Jacopo Vivian: meaning that if you place that value email
05:30:630Jacopo Vivian: any circuit in any hydraulic system in the world
05:36:751Jacopo Vivian: with those boundary conditions between 5 and 30 Celsius degrees.
05:43:00Jacopo Vivian: and with a pressure difference across the valve of one bar.
05:49:520Jacopo Vivian: you will achieve exactly that flow, that nominal flow rate, the flow factor. Okay, so
06:01:780Jacopo Vivian: usually the definition is kv, one or Kv, something. Okay, depending on the convention that we use.
06:12:590Jacopo Vivian: which means the Kv with the valve fully open.
06:17:930Jacopo Vivian: Okay, so when you have a browser you have it fully open, and the fully closed
06:26:380Jacopo Vivian: position of the valve
06:29:490Jacopo Vivian: and the flow rate at those boundary conditions with the valve fully open is the Kv one. On the right you can see a diagram
06:38:940Jacopo Vivian: which gives you the.
06:43:440Jacopo Vivian: Let me use the pointer that gives you the Kv, the ratio between Kv and Kv one. Okay.
06:55:230Jacopo Vivian: so
06:56:650Jacopo Vivian: as you can understand, if the flow for those specific conditions temperature and the Delta P. Especially delta. P.
07:07:699Jacopo Vivian: Compared to the maximum flow rate at those condition which is kv. One. And it's typical for that value. So
07:17:390Jacopo Vivian: each valve has a Kv one, which is, it's nominal value. Okay?
07:24:880Jacopo Vivian: And what we have on the x-axis, we have the opening. So X is the opening.
07:31:860Jacopo Vivian: which is 0 in case of fully closed and equal to x. 1.
07:40:570Jacopo Vivian: So that X divided by x, 1 is one in fully open condition.
07:47:170Jacopo Vivian: So these diagrams show us what happens between them
07:53:20Jacopo Vivian: the fully open and the fully closed condition with the different, with vows that have different characteristics.
08:02:820Jacopo Vivian: So that means we can have 2 valves that have the same Kv. One.
08:12:230Jacopo Vivian: but so the same flow factor.
08:14:830Jacopo Vivian: But they have different characteristic curves
08:18:380Jacopo Vivian: like those shown in this diagram.
08:22:130Jacopo Vivian: this characteristic, so to have a and calling
08:31:980Jacopo Vivian: no course, no linear, but also very quick opening.
08:41:140Jacopo Vivian: are, in fact, called a quick opening voucher. Okay?
08:45:980Jacopo Vivian: And then you have linear
08:49:410Jacopo Vivian: a linear characteristic, or you have the equal percentage value. What is the difference between these is as the name suggested.
08:59:730Jacopo Vivian: the quick opening means that as soon as you
09:04:380Jacopo Vivian: start opening the valve. So at the low aperture of the open of the
09:11:980Jacopo Vivian: valve, you have a sudden increase of flow. You can see, for example, for this characteristic. You have that at 20% opening, you have 75% of the flow of the nominal flow.
09:30:680Jacopo Vivian: and the rest is a achieved in the remaining 80% of the offering
09:37:750Jacopo Vivian: linear is linear meaning the 50% that is fif 50% opening there will lead to 50% flow.
09:46:730Jacopo Vivian: An equal percentage is more or less the other way around of
09:54:610Jacopo Vivian: of quick on opening meaning that
09:58:833Jacopo Vivian: you need to open more than 50%
10:04:490Jacopo Vivian: in order to achieve a 50% flow.
10:08:40Jacopo Vivian: Okay?
10:10:430Jacopo Vivian: So I think it's quite intuitive.
10:15:190Jacopo Vivian: So yes. So these are the 3 types of quick opening valves, linear valves and equal percentage valves.
10:29:550Jacopo Vivian: Let's look how they achieve this different behavior.
10:37:650Jacopo Vivian: They have an opening which is geometrically different.
10:42:380Jacopo Vivian: Okay, so as you can see the equal percentage. When it closes, it does not obstruct fully the opening.
10:55:490Jacopo Vivian: whereas the linear opening is a constant in the direction of the closure.
11:04:460Jacopo Vivian: Okay. So therefore, we achieve this characteristic.
11:09:730Jacopo Vivian: Now, I want to show you
11:11:910Jacopo Vivian: why equal percentage voucher are typically used for control. Because since.
11:25:120Jacopo Vivian: So since you have, and there's a long flow at 50%,
11:36:760Jacopo Vivian: since you have the no- no, as soon as you open.
11:41:150Jacopo Vivian: okay? And the heat output of the terminal unit has a similar characteristics with the with the flow.
11:52:200Jacopo Vivian: you achieve a an almost linear heat output with the opening.
11:58:140Jacopo Vivian: So basically the the characteristic curve of the of the valve
12:05:290Jacopo Vivian: will compensate the law of the the heat output of the terminal units.
12:13:430Jacopo Vivian: so that if you put them together you achieve that the heat output changes almost linearly with the with the valve opening. Okay, that's why equal percentage valves are used for for control.
12:37:230Jacopo Vivian: So but now we don't we-we want to talk in general about the the 3 of them.
12:46:590Jacopo Vivian: So, as the name suggests, quick opening path are used for those systems where
12:54:160Jacopo Vivian: we really need to provide them. High flow rates in a small amount of time.
12:59:990Jacopo Vivian: Okay?
13:01:290Jacopo Vivian: Or for systems with frequent on off.
13:05:270Jacopo Vivian: So those systems are typically cooling systems.
13:10:10Jacopo Vivian: Because remember that cooling systems differently from the heating system.
13:18:590Jacopo Vivian: I'm talking about systems with large flow rates. Okay.
13:24:210Jacopo Vivian: those systems cooling systems don't work at 24, 7.
13:29:470Jacopo Vivian: They typically work during a limited amount of time.
13:35:80Jacopo Vivian: So the number of hours of operation is smaller
13:40:500Jacopo Vivian: is lower compared to keeping systems in general.
13:45:930Jacopo Vivian: and they also have, as we already said, that lower density.
13:51:20Jacopo Vivian: Okay, so that's why.
13:56:420Jacopo Vivian: For, as I already have introduced in last lecture, cooling systems are Systema with the large flow rates. Okay.
14:07:480Jacopo Vivian: compared to heating systems.
14:09:810Jacopo Vivian: And then we have, for example, safety secret.
14:13:610Jacopo Vivian: Okay, like fire safety.
14:16:560Jacopo Vivian: They are systems where you want to deliver a large amount of water flow in a small amount of time. So for those for those systems, quick opening valves are are good.
14:34:890Jacopo Vivian: and then for linear control valves, we use them for liquid level control or flow control.
14:43:400Jacopo Vivian: Typically, we have a storage of water, and we need to deliver water from that storage.
14:53:320Jacopo Vivian: Okay, without, we don't care about the temperature. We don't care about the heat.
14:59:650Jacopo Vivian: In that case, it's a linear control data. It's it's useful.
15:06:30Jacopo Vivian: Okay?
15:07:920Jacopo Vivian: Why? Because in those systems the Delta P across the valve is expected to remain quite constant. Okay,
15:23:630Jacopo Vivian: the remaining balls, equal percentage control valves are the most used for control. So for the regulation of systems.
15:35:10Jacopo Vivian: because they because in general, we want to have the temperature control flow control.
15:43:790Jacopo Vivian: and we have a variable Delta P across the value because the system is continuously changing its working conditions.
15:57:860Jacopo Vivian: Okay.
16:03:620Jacopo Vivian: so big opening voucher are bold voucher. They have low cost.
16:11:880Jacopo Vivian: They have low leakage, they resist high pressure.
16:17:430Jacopo Vivian: So they have a tight ceiling. Okay, the low leakage means tight ceiling.
16:29:250Jacopo Vivian: And the the disadvantage are are that they are
16:33:980Jacopo Vivian: and unsuitable to Larry. Okay, so dirty carbon fluids of the clean technical water.
16:47:865Jacopo Vivian: Limited throttling mean means limited capability to control.
16:54:900Jacopo Vivian: That's why they are used for as we talking about.
16:58:760Jacopo Vivian: and they are prone to cavitation.
17:01:960Jacopo Vivian: Quiet cavitation, because the Delta P across the valver camera can lead to have low pressure, low static pressure.
17:18:609Jacopo Vivian: and we reach the saturated upward pressure at that temperature.
17:23:680Jacopo Vivian: Okay, this can be at the partial opening of can happen at partial opening of the valve, not only with all valves, but also with other types.
17:36:820Jacopo Vivian: So then we have Gate Valson.
17:41:780Jacopo Vivian: They also have a low cost.
17:45:760Jacopo Vivian: they are suited to fully open or fully closed the operation.
17:50:830Jacopo Vivian: so not the partial in partial opening conditions.
17:56:770Jacopo Vivian: differently from borders they can also operate with.
18:03:540Jacopo Vivian: and this they they also have a tight shut off.
18:08:70Jacopo Vivian: They are also not good for control.
18:12:470Jacopo Vivian: and they exhibit the same problem of communication.
18:23:990Jacopo Vivian: Then we have butterfly bars. In this case we have okay.
18:34:150Jacopo Vivian: They are used for for control.
18:37:490Jacopo Vivian: They are reliable for frequent operation, meaning that you don't only use them to fully open and fully close.
18:48:450Jacopo Vivian: but also for partial load operation of the system.
18:56:110Jacopo Vivian: And they are a cheap solution for high flow application, water, treatment, fire production.
19:08:750Jacopo Vivian: Yeah, they they they don't have a good control characteristic.
19:18:420Jacopo Vivian: Okay for Hvac systems as a global browser.
19:26:340Jacopo Vivian: Because they there is a high
19:31:230Jacopo Vivian: I talk is required to control them.
19:35:110Jacopo Vivian: You can understand it by looking at how they are built.
19:39:300Jacopo Vivian: They have this disk.
19:41:990Jacopo Vivian: Okay?
19:43:250Jacopo Vivian: And of course, depending on the position of the disk. You have a higher dark.
19:51:640Jacopo Vivian: in the in the almost close position, which is quite high. So it's not very used for for this purpose
20:04:640Jacopo Vivian: group also have a can regulate the flow precisely, and they are used also in a wider range of
20:20:714Jacopo Vivian: They can give a wide range of controllability. Okay?
20:24:910Jacopo Vivian: And they can also work with high pressure difference.
20:29:450Jacopo Vivian: But they are more expensive than butterfly dollars.
20:34:780Jacopo Vivian: Okay, low shut off. Capability means that the they are
20:49:360Jacopo Vivian: they are not used to shocked.
20:53:820Jacopo Vivian: Okay, slow, very quickly. Okay.
21:00:530Jacopo Vivian: Okay. Other other characteristics. Other metrics that we use to to define vals, the minimum flow rate
21:12:680Jacopo Vivian: below which the regulation is not possible. We call it K, 0, a K is missing in the
21:20:980Jacopo Vivian: in the drawing. Yeah.
21:24:730Jacopo Vivian: But basically here, this is very close to 0. But in general we have a Kv 0, a minimum flow.
21:33:560Jacopo Vivian: We know which regulation is not possible.
21:39:220Jacopo Vivian: If imagine that it would be here, we wouldn't
21:43:790Jacopo Vivian: not be able to regulate the the flow
21:48:510Jacopo Vivian: between 0 and 10% of the Kv one value.
21:54:160Jacopo Vivian: Okay? Because in that region you don't put the the value, the behavior of the of the flow does not follow this flow here.
22:05:650Jacopo Vivian: but it follow it. It will fluctuate okay because of
22:14:110Jacopo Vivian: to to enter, because how they are designed, basically.
22:20:940Jacopo Vivian: And then we have the arrangeability which depends on the Kv. 0,
22:27:590Jacopo Vivian: which is useful because it gives us a
22:33:860Jacopo Vivian: once we have the Kv one, the range ability gives us the the minimum controllable controllable flow. Okay, so if we have. Kv. One. Arrangeability. We can calculate the Kv. 0, and therefore we can understand the minimum controllable flow, but also because they it gives the curvature of the characteristic curve. Here you can see
22:59:520Jacopo Vivian: that these curves depend on the range ability. So this curve with R equal to 20,
23:07:540Jacopo Vivian: is closer to the linear behavior compared to the
23:11:760Jacopo Vivian: equal percentage value with the range ability equal to 50.
23:17:220Jacopo Vivian: Okay.
23:25:40Jacopo Vivian: most importantly, for a regulation.
23:29:940Jacopo Vivian: we have the vulnerability. Why is this vulnerability so important because it's the metric that we use to select the value.
23:40:310Jacopo Vivian: Okay, what does it mean? Selecting about
23:44:770Jacopo Vivian: it means that we are relying the system.
23:48:720Jacopo Vivian: And we want to choose a certain value that is suitable for that system.
23:56:540Jacopo Vivian: Okay, and we cannot only make this choice based on the flow factor. The flow factor is not enough.
24:05:600Jacopo Vivian: I cannot just choose a evolve based on the flow factors.
24:13:30Jacopo Vivian: Okay? Why?
24:15:750Jacopo Vivian: Because I don't know if
24:20:510Jacopo Vivian: I don't know. I'm not considering the desktop fee that will be actually present in the system.
24:31:290Jacopo Vivian: while with the develop authority, I consider the Delta PIN
24:36:680Jacopo Vivian: the pressure difference across the valve.
24:40:200Jacopo Vivian: And this is the most important thing, because you know that the flow is driven by the Delta. P.
24:48:620Jacopo Vivian: Okay, so
24:52:110Jacopo Vivian: what what is the definition of the valid authority. It is the ratio between the Delta P across the valve in fully open position.
25:03:20Jacopo Vivian: and the sum of this 10 delta P. And the Delta P of the remaining part of the secret, and then I will make an example so that it will be more clear.
25:17:170Jacopo Vivian: But BA- basically, you have a a hydraulic series like those that we have seen so far.
25:24:570Jacopo Vivian: and that's the PC.
25:27:490Jacopo Vivian: Describes the all the pressure drops, sir.
25:31:770Jacopo Vivian: in the secret, and without that excluding Delta. Pv.
25:39:260Jacopo Vivian: Okay. So, excluding the Delta P across the value
25:44:530Jacopo Vivian: and Delta PV. Is exactly
25:48:190Jacopo Vivian: there. There's a piece between the inlet and outlet of the browser.
25:54:760Jacopo Vivian: we just in the fully open position.
25:57:980Jacopo Vivian: Give me one line again.
26:01:140Jacopo Vivian: It's the Delta is for safe with them.
26:05:90Jacopo Vivian: Okay, so B is for valve, and C is for
26:09:810Jacopo Vivian: the secret excluding the value itself.
26:14:580Jacopo Vivian: But now I will make an example, so that it will be more clear.
26:18:970Jacopo Vivian: So how is why is alpha useful? Because we know that alpha needs to be in a certain range.
26:29:840Jacopo Vivian: because there is a trade off between high pressure losses and controllability.
26:40:980Jacopo Vivian: If we need the device to control
26:44:60Jacopo Vivian: the flow or the temperature in a system.
26:47:830Jacopo Vivian: we need to be able to operate in that in that system
26:51:980Jacopo Vivian: with those pressure drops that we have calculated. Okay?
26:56:690Jacopo Vivian: So if Alpha or the voluntary is below 30%,
27:04:290Jacopo Vivian: we are unable to properly control the flow.
27:09:640Jacopo Vivian: Okay, good.
27:12:270Jacopo Vivian: And the if alpha is higher than 50%,
27:18:660Jacopo Vivian: we can control the the flow. But we have a high pressure drop.
27:28:170Jacopo Vivian: So we need something in between.
27:32:70Jacopo Vivian: What does the alpha equal to 30% mean?
27:41:240Jacopo Vivian: It means that if you, if you replace Alpha equal to 30%, you will see that it corresponds to
27:49:200Jacopo Vivian: a situation where Delta P is almost is more or less equal to Delta. PC.
27:56:940Jacopo Vivian: Okay.
27:57:820Jacopo Vivian: So this means that in general the Delta P across the valve should be more or less equal to the pressure drop in the remaining part of the hydraulic.
28:12:100Jacopo Vivian: This is a good compromise between controllability and high pressure losses.
28:19:610Jacopo Vivian: And you know, of course, that the high pressure losses mean that the you will spend more energy
28:29:20Jacopo Vivian: for your auxiliary systems or pumps circulation pumps.
28:40:520Jacopo Vivian: We have a correlation that we can use in technical unit to
28:54:190Jacopo Vivian: to calculate the Delta P across the value
28:58:300Jacopo Vivian: depending on the flow which circulate through it.
29:03:70Jacopo Vivian: Okay of here.
29:05:940Jacopo Vivian: Remember, that is only valid with those units.
29:10:390Jacopo Vivian: So in case you have different units, please compare
29:14:830Jacopo Vivian: otherwise, then you will get the very strange values.
29:20:80Jacopo Vivian: Okay, yeah.
29:26:700Jacopo Vivian: I will. I will make an example later.
29:31:650Jacopo Vivian: But before I need to start talking about the
29:37:210Jacopo Vivian: 5 of regulation parts that we typically encounter in Hvac systems. We have either 2 way outs or 3 way outs.
29:47:190Jacopo Vivian: Let's talk about tubervals. First, st here is the here you find the
29:54:00Jacopo Vivian: and an example of 2 way voucher
29:58:100Jacopo Vivian: with the manual or with the motorized actuation.
30:04:640Jacopo Vivian: Okay, they are typically used to control the flow rate
30:11:850Jacopo Vivian: and to adapt it to local energy, demand in variable flow systems.
30:19:460Jacopo Vivian: You know, in general, we have either constant flow or variable flow, and then
30:27:780Jacopo Vivian: I will show how we of course, it depends on the pump
30:34:810Jacopo Vivian: whether we are able to change the speed of the power or not. In all systems
30:41:150Jacopo Vivian: we have a constant speed pumps.
30:44:240Jacopo Vivian: Okay? And you can change the number of active pumps.
30:49:180Jacopo Vivian: Go ahead.
30:50:270Jacopo Vivian: This is the case of our
30:54:80Jacopo Vivian: district heating network of the Northeas area
30:58:530Jacopo Vivian: that we will visit on the 26th of May.
31:03:520Jacopo Vivian: We will do a technical visit there with our colleague from the Facility Energy Management Office.
31:11:310Jacopo Vivian: and we will show you the substations of the distributing network and the brand new pulling station of the system that they just replaced.
31:23:970Jacopo Vivian: So and also some air handling units and the network itself. Before that technical visit I will take a lecture on district heating systems that are
31:39:480Jacopo Vivian: exactly big hydraulic systems. So you will.
31:44:280Jacopo Vivian: I will just upscale the all this more. You look at the the technical part of the hydraulic systems.
31:54:360Jacopo Vivian: and then there will be a lecture on
32:01:510Jacopo Vivian: let's say, on the bigger scale, on how district heating systems work, how they are designed, and we will visit the the hydraulic system or the distributing system serving the university building in the north of area.
32:18:660Jacopo Vivian: So
32:21:780Jacopo Vivian: the typical uses of 2 way bars. In that case. Sorry. That was to say that that is a node network that works with constant speed pumps.
32:34:40Jacopo Vivian: So it's not a very a valuable choice.
32:40:900Jacopo Vivian: In this case typical examples of valves are
32:48:650Jacopo Vivian: of 2 way. Valves are them thermostatic valves in radiative systems.
32:54:490Jacopo Vivian: Remember that radiative systems can be either supplied by the 2 way separate with direct or reverse return, or with the one pipe with the in parallel connection
33:10:540Jacopo Vivian: we have seen in the 1st lecture.
33:13:30Jacopo Vivian: So in that case the thermostatic valve is placed on the
33:18:850Jacopo Vivian: pipe connecting to the one pipe system, or in there supply
33:27:00Jacopo Vivian: connected to the supply line of the system. Okay, remember that thermostatic value.
33:37:345Jacopo Vivian: Open and closer
33:39:740Jacopo Vivian: the the and let the flow enter or not to the single terminal unit. In that case, in that case, radiator, depending on the temperature in that room.
33:55:280Jacopo Vivian: Okay?
33:56:820Jacopo Vivian: So then, we have 2 way about phone call experience.
34:04:400Jacopo Vivian: 2 way about seeing. And this is a case that I was talking about substations of district heating networks.
34:14:969Jacopo Vivian: Okay, you can have it also in constant flow systems.
34:19:350Jacopo Vivian: But they are typical also for viable flow systems.
34:24:120Jacopo Vivian: And I I will later on. I will explain how how they work in district heating networks.
34:30:179Jacopo Vivian: But basically, this is the you know, it's a very simple.
34:34:860Jacopo Vivian: They just close it partially there, at the
34:44:80Jacopo Vivian: they close partially the passage to the to the flow, and still
34:50:560Jacopo Vivian: the new. You may remember the working point in a hydraulic system is given by the intersection between the characteristic curve of the pump and the characteristic curve of the sleep
35:05:330Jacopo Vivian: we see. We saw with that last lecture.
35:10:960Jacopo Vivian: but that was in the design phase.
35:15:620Jacopo Vivian: Today we see what happens in the normal operation of the system.
35:21:510Jacopo Vivian: so I will show it that later.
35:25:10Jacopo Vivian: But for now you just see how
35:29:240Jacopo Vivian: how it the the principle is is very simple. So you have the loader. It could be a part of the keeping system, or it could be simply a terminal unit. Okay, in general, it's the loader.
35:46:30Jacopo Vivian: and then the valve is closing
35:52:256Jacopo Vivian: or opening it, depending on the flow. So it's a way to adjust the flow.
35:59:820Jacopo Vivian: so that if the heating load is lower, also, the flow will be lower.
36:05:880Jacopo Vivian: It's very simple. Okay.
36:10:00Jacopo Vivian: And, as you can see in the drawing, you can place it either in the supply or in the return pipe
36:18:590Jacopo Vivian: today on the okay. Now, let's make an example on how to select, then, a partner.
36:32:200Jacopo Vivian: For this sharepoint.
36:34:920Jacopo Vivian: We have the 3 options, we have valve A, B and C with 3 values of Kv. One.
36:44:130Jacopo Vivian: and we needed to control the flow in a circuit with the design flow rate of 1,500 liters per hour.
36:57:20Jacopo Vivian: and the pressure loss in the circuit excluding the valve. So from this point to this point.
37:04:840Jacopo Vivian: and from this point to including the terminal unit and then back.
37:11:380Jacopo Vivian: okay, you have the desktop P equal to 6 Kilo Pascal.
37:18:510Jacopo Vivian: So now I need to
37:35:140Jacopo Vivian: share this.
37:53:690Jacopo Vivian: Whoa.
38:19:160Jacopo Vivian: don't.
38:24:460Jacopo Vivian: Wow, so we have this situation here.
38:51:220Jacopo Vivian: and the the data is.
38:57:100Jacopo Vivian: no is a white.
39:03:00Jacopo Vivian: It's terrible. They gave me a very bad time.
39:13:944Jacopo Vivian: Improve.
39:15:650Jacopo Vivian: It's going
39:25:410Jacopo Vivian: not very much.
39:34:310Jacopo Vivian: 10th of P.
39:39:120Jacopo Vivian: I don't know if did the user usually professors use the
39:48:940Jacopo Vivian: this whiteboard? Normally graphical? No, okay,
40:00:80Jacopo Vivian: no, this is not possible. Right?
40:03:420Jacopo Vivian: So I will do it with excel.
40:12:200Jacopo Vivian: But then I need to reshare the screen.
40:17:370Jacopo Vivian: Yes, but no, because I cannot record the video with this laptop.
40:27:320Jacopo Vivian: Okay. But I try with the with excel. I think it's if this one.
41:01:780Jacopo Vivian: okay, okay. Now, you should be able to see my screen with excel.
41:12:490Jacopo Vivian: I am sharing it. So everything should be fine.
41:17:450Jacopo Vivian: Okay, so basically, we have valve, 3 bags.
41:24:730Jacopo Vivian: We have a B and C,
41:28:690Jacopo Vivian: and for each of them we have a Kv. One.
41:32:660Jacopo Vivian: which is in the 1st case, 18 cubic meters per hour, in the second case 6.
41:39:330Jacopo Vivian: And in the 3rd case 3.
41:43:360Jacopo Vivian: So then we have that the Delta P of the circuit. So the Delta PC. Is 6
41:54:130Jacopo Vivian: Giro Pascal.
41:57:870Jacopo Vivian: Okay, so we need to choose
42:02:380Jacopo Vivian: the the browser between these 3 options
42:08:100Jacopo Vivian: by knowing that the nominal flow rate will be 1,500 liters per hour.
42:17:130Jacopo Vivian: These are the data that we have.
42:20:330Jacopo Vivian: Okay.
42:22:930Jacopo Vivian: So we can calculate, then Delta P across the valve
42:33:90Jacopo Vivian: with the correlation that I gave you before.
42:39:720Jacopo Vivian: So the we calculate the Delta P across the valve.
42:50:300Jacopo Vivian: which is
43:01:500Jacopo Vivian: but it doesn't
43:10:340Jacopo Vivian: this 1 0. So the the
43:17:90Jacopo Vivian: result is in meter millimeters of water column.
43:21:470Jacopo Vivian: Is it equal to 0 point 0 1
43:24:670Jacopo Vivian: times the square of the ratio between the flow rate which is already in the unit we want and the Kv. One which is already in the units we want.
43:35:410Jacopo Vivian: So just the result is in a different unit.
43:40:400Jacopo Vivian: Okay, so any questions, okay, so the Delta P is 0 point 0 1 times.
43:56:190Jacopo Vivian: I'm not sharing anymore. Okay, yes. 0 point 0 1 times the
44:07:540Jacopo Vivian: If the ratio between flow rate, the nominal flow rate and the Kv one, okay,
44:23:430Jacopo Vivian: I block this cell power to.
44:30:200Jacopo Vivian: Okay.
44:31:440Jacopo Vivian: So this is the Delta Pv. Of
44:35:600Jacopo Vivian: across the valve of the 3 valster.
44:40:990Jacopo Vivian: And this result is being millimeters of water column.
44:48:980Jacopo Vivian: So now, I can convert to meet person.
44:56:500Jacopo Vivian: Okay, so it's just this times, 0 0 1.0 0 1.
45:05:560Jacopo Vivian: Okay?
45:09:780Jacopo Vivian: And then we convert to Kilo Pascal
45:14:120Jacopo Vivian: in order to have the same unit that we have for Delta, PC.
45:20:20Jacopo Vivian: So one meter of water column is 9.8 1 Kilo Pascal.
45:28:920Jacopo Vivian: So I just multiply this by 9.81, which is the gravity acceleration.
45:44:200Jacopo Vivian: Good.
45:45:950Jacopo Vivian: So, okay, so we are able now to calculate the authority of the value for each of them.
45:58:90Jacopo Vivian: which depends on the circuit where we are placing this valve great.
46:05:20Jacopo Vivian: So we see how, where it fits to this specific sphere quit, and to do it.
46:12:210Jacopo Vivian: we calculate the Delta Pv divided by
46:18:60Jacopo Vivian: Delta, PV plus delta. PC.
46:26:690Jacopo Vivian: Okay, so these pose a V, not the C, okay. And the result is
46:39:170Jacopo Vivian: that the Val A would give us a valid authority of 10%,
46:45:740Jacopo Vivian: which means low delta P. In fact, we see
46:50:930Jacopo Vivian: 7 cm of water water column. It's a low delta P across the valve, but this will not give us good controls over the flow.
47:02:700Jacopo Vivian: Okay, for this means poor control, because it's lower than 30%.
47:14:880Jacopo Vivian: And this case is I, Delta, P
47:22:890Jacopo Vivian: point 2.5 meters of water column across the world.
47:32:500Jacopo Vivian: So in this example we choose
47:36:860Jacopo Vivian: the vase being the 2 way Vaulse.
47:40:760Jacopo Vivian: That is a good compromise to control the flow, and then, without having excessive pressure, drop across the world.
47:54:560Jacopo Vivian: Okay? So I can now go back to the presentation because we need to
48:03:350Jacopo Vivian: switch to the other type of valves that are a bit more complicated.
48:16:100Jacopo Vivian: The dark. 3 way vows.
48:25:730Jacopo Vivian: Okay?
48:28:570Jacopo Vivian: Why? How?
48:31:30Jacopo Vivian: Why do we use 3 wave? Also, we use them to control not only the flow, but also the temperature.
48:40:120Jacopo Vivian: Okay.
48:42:230Jacopo Vivian: So, depending on how we place the valve, and typically, we place it either in mixing mode, so mixing valves or in diverting mode, diverting valve
48:57:960Jacopo Vivian: depending on where we place the 3 way valver
49:02:920Jacopo Vivian: in the circuit, we can either control the temperature or the flow.
49:08:630Jacopo Vivian: Okay. And now we will see all the combinations that are possible uses of 3 way valve
49:19:525Jacopo Vivian: so basically, an example of mixing valve is on the supply line
49:27:330Jacopo Vivian: downstream of generation system, diverting valves on the return line downstream of heating loads.
49:36:60Jacopo Vivian: But I think it is more clear if we look at the schematics.
49:42:130Jacopo Vivian: So
49:47:140Jacopo Vivian: for 3 way valves. We we have these types of of valves, globe valves
49:58:320Jacopo Vivian: in the, in these notes that there is a plug
50:03:190Jacopo Vivian: that has a linear movement. You can see it on the left.
50:08:600Jacopo Vivian: Okay, which is mechanically connected to a moving part called stem.
50:17:830Jacopo Vivian: Let me take the pointer.
50:21:30Jacopo Vivian: This is the 10, and this is the
50:30:830Jacopo Vivian: obturator of the globe valve.
50:34:980Jacopo Vivian: By changing the position of the operator we achieve
50:40:420Jacopo Vivian: the passage of the flow from the inlet to the outlet.
50:46:250Jacopo Vivian: So we either have one inlet and 2 outlets, or in this case, it's a diverting valve, or we have
50:57:10Jacopo Vivian: 2 inlets and one outlet. And in this case it's a mixing valve.
51:02:20Jacopo Vivian: Okay?
51:03:160Jacopo Vivian: So if we mix 2 flows, it's a mix involved in this case, we have 2 inlets and one outlet.
51:09:990Jacopo Vivian: or if we have one inlet and 2 outlets, we divert to the flow. So it's a diverting valve.
51:17:500Jacopo Vivian: and you can see that in sector valves, you obtain the same effect with a different design. Basically.
51:28:40Jacopo Vivian: So in this case the movement, the mechanical movement of the obturator is not linear, but it is
51:36:320Jacopo Vivian: on a
51:39:740Jacopo Vivian: It's a rotation, okay, on its axis, on its own axis.
51:46:700Jacopo Vivian: and by rotating it opens different parts and it changes the alerts. The flow go to the correct
51:59:280Jacopo Vivian: in the correct direction.
52:02:990Jacopo Vivian: Globe valves are more precise than sector valves.
52:09:800Jacopo Vivian: Okay, they need more space. And there is these 2 higher pressures.
52:17:240Jacopo Vivian: So sector valves are more compact, less precise, but they register to higher delta. P.
52:30:950Jacopo Vivian: Yeah. So they they for higher Delta P. They cannot leak
52:36:510Jacopo Vivian: so with high Delta. P. It is better to use globe valves. Okay.
52:48:40Jacopo Vivian: okay, let's look at one example of
52:52:860Jacopo Vivian: a mixing valve. We have imagined to have a constant
52:58:930Jacopo Vivian: pump, a constant flow pump on the right here.
53:06:590Jacopo Vivian: Okay, there is a seed to remember that is constant, and we want to
53:18:00Jacopo Vivian: control the temperature to the load.
53:21:630Jacopo Vivian: Okay, in this case the temperature will depend on the opening, on the flow that comes from the bypass.
53:32:360Jacopo Vivian: Why is the flow coming from here to here.
53:41:480Jacopo Vivian: If no, if we increase the bypass, it will decrease the supply temperature because there is more return
53:51:420Jacopo Vivian: that will mix with the supply. Okay in in heating, of course, and talking about heating.
53:59:30Jacopo Vivian: But my question is different is not why we are using a 3 way valve. My question is.
54:05:920Jacopo Vivian: why the flow, when I open this valve will flow in this direction, and not in this direction.
54:17:570Jacopo Vivian: is at a lower threshold than
54:25:640Jacopo Vivian: your colleague is is right. The pressure here
54:30:50Jacopo Vivian: is higher than the pressure here.
54:32:690Jacopo Vivian: Why? Because we have a pump here.
54:36:630Jacopo Vivian: Okay, so always think when you look at 3 wave apps, always think about the pressure.
54:47:370Jacopo Vivian: Okay?
54:49:90Jacopo Vivian: So because it depends on the position of the pump. In this case, the pressure here is higher than the pressure here. Of course, if we see the arrow we already know.
55:01:500Jacopo Vivian: But in general, if you draw a system, you don't have the arrow, you need to draw the arrow. Okay?
55:09:130Jacopo Vivian: So that's why I'm I'm telling this.
55:15:620Jacopo Vivian: Okay, then we have another example.
55:21:310Jacopo Vivian: We have
55:27:150Jacopo Vivian: this.
55:30:480Jacopo Vivian: So in in the 1st case, we have the possibility to control the supply temperature to the heat exchanger or whatever. This is okay to the load.
55:42:390Jacopo Vivian: In the second case we have the pump on the left so before the bypass, which means that in this case, since we only have pressure drops here.
55:55:340Jacopo Vivian: it means that for sure the pressure here will be higher than the pressure here.
56:01:340Jacopo Vivian: And that's why this mixing valve. This is a mixing valve. Okay.
56:08:210Jacopo Vivian: that mixes the return from the load with the supply.
56:13:360Jacopo Vivian: So this is used to control
56:19:860Jacopo Vivian: the temperate, the return temperature, because the higher the mixing.
56:25:700Jacopo Vivian: the higher the mass flow rate through the bypass.
56:29:730Jacopo Vivian: the higher will be the return temperature to the generation units.
56:34:950Jacopo Vivian: Okay?
56:36:760Jacopo Vivian: And the higher the masculating, the bypass.
56:41:380Jacopo Vivian: the lower the flow rate to the load.
56:47:160Jacopo Vivian: Okay?
56:49:350Jacopo Vivian: So in this case we adapt the the return temperature.
57:01:500Jacopo Vivian: 2 meet a certain requirement in terms of return temperature to the generation.
57:13:80Jacopo Vivian: and then we have the possibility of using diverting valves.
57:21:470Jacopo Vivian: This is a diverting bag on the supply.
57:28:30Jacopo Vivian: but I don't like this drawing very much is not very clear, so I will make it on the blackboard.
57:44:510Jacopo Vivian: So we have a and now growing $15 similar to the mixing power.
57:53:690Jacopo Vivian: But
57:57:950Jacopo Vivian: this user and my director now.
58:05:720Jacopo Vivian: So here we have the constant.
58:09:260Jacopo Vivian: I say, constant has to be.
58:11:910Jacopo Vivian: say, Okay, it depends on the fund. It could also be in principle, it could also be a value. But let's
58:18:900Jacopo Vivian: assume that this already depends, and good
58:26:870Jacopo Vivian: depending on how much this world is open.
58:32:960Jacopo Vivian: a part of this floor input will directly will bypass the login.
58:38:490Jacopo Vivian: Okay?
58:39:600Jacopo Vivian: So in this case, we are controlling the flow to the load.
58:45:10Jacopo Vivian: Okay, we are.
58:48:660Jacopo Vivian: I've seen flow control and not temperature control like before. Okay?
58:57:170Jacopo Vivian: Because, of course the temperature will be the same. Here we are just diverting at the part of the mass flooring.
59:05:320Jacopo Vivian: and then we have the last laser which user.
59:26:340Jacopo Vivian: Here you are.
59:34:960Jacopo Vivian: So we had, yeah, constant meaning, your fund driven mass flow to the to the loader.
59:46:540Jacopo Vivian: So here the pressure is higher than here.
59:52:540Jacopo Vivian: Okay? Because between these 2 points we only have pressure drops. So we have a this situation here, too.
00:07:340Jacopo Vivian: So in this case, what do we achieve?
00:16:600Jacopo Vivian: We achieve.
00:21:280Jacopo Vivian: If temperature comes out to the node
00:25:410Jacopo Vivian: with the divert in 3 way bound, placed on the return, because the diverting
00:35:240Jacopo Vivian: basically the divert about on the return is acting
00:39:790Jacopo Vivian: like a 3 way mixing valve on the slide. Here.
00:44:370Jacopo Vivian: you see, it has the same.
00:46:790Jacopo Vivian: more or less the same. Then working principle.
00:58:180Jacopo Vivian: I prefer these schematics to the one of the slides, so
01:09:80Jacopo Vivian: no, the mass flow rate is below the is that decided by this bumper.
01:19:910Jacopo Vivian: We are controlling the
01:25:210Jacopo Vivian: so the- the viable flow is to the generation unit, depending on how much water goes and how much flow goes to the bypass.
01:36:890Jacopo Vivian: But we are fulchieving the mixing here
01:41:980Jacopo Vivian: that we change the supply temperature to the load. So we have constant flow and variable temperature to the to the load.
01:52:762Jacopo Vivian: The temperature. Yes.
02:01:860Jacopo Vivian: okay.
02:03:10Jacopo Vivian: Now, we need to complete the this
02:11:210Jacopo Vivian: this topic by looking at the other side, which is the phone.
02:18:760Jacopo Vivian: Okay, how can we adopt the pump, or what happens
02:25:570Jacopo Vivian: with the pump? Because we just said, Okay, we need to place this bolster to reduce or increase the flow.
02:33:70Jacopo Vivian: to change, increase or reduce the temperature to the load or to the generation.
02:39:770Jacopo Vivian: But we didn't say much about the plant, so
02:46:840Jacopo Vivian: remember that if we close a 2 way, valve.
02:52:930Jacopo Vivian: What we achieve is this a change?
02:59:510Jacopo Vivian: You remember the green curve is the characteristic curve of the circuit of the hydraulic system.
03:07:680Jacopo Vivian: And then.
03:12:170Jacopo Vivian: Orange, I don't know. I have a problem with colors.
03:16:310Jacopo Vivian: Curve is the factory characteristic curve.
03:20:430Jacopo Vivian: So imagine that A is the
03:25:30Jacopo Vivian: design point where the true curves
03:29:200Jacopo Vivian: in with the intersection of the curves, and then we
03:35:520Jacopo Vivian: close a 2 without going to a lot.
03:40:860Jacopo Vivian: So we expect that
03:43:180Jacopo Vivian: to have higher pressure losses because we have an obstruction to the flow, but also to have a lower flow.
03:52:780Jacopo Vivian: And, in fact, this is what happens. The characteristic curve of the of the circuit will change.
04:00:530Jacopo Vivian: because now we have more delta. P. So our curve that we have defined yesterday as a sum of your continuous and localized pressure losses will change because we have a more localized pressure losses due to the
04:20:950Jacopo Vivian: closure of the 2 way valve, and therefore it will shift from
04:29:970Jacopo Vivian: this position from this curve to the dashed line.
04:35:60Jacopo Vivian: and if the pump speed remains the same, the new
04:41:460Jacopo Vivian: operating point of the system will be be
04:45:480Jacopo Vivian: okay. You can see, in fact, that it has a lower flow and higher data speed.
04:53:220Jacopo Vivian: But we, in case we have a variable speed pump, we can change it.
05:01:110Jacopo Vivian: We can lower the speed of the pump.
05:05:800Jacopo Vivian: Okay?
05:07:170Jacopo Vivian: And we can do it. So that like, in this case, the Delta P is constant, correct.
05:16:330Jacopo Vivian: So this is a hello that we can
05:21:921Jacopo Vivian: user. We measure the Delta P between inlet and outlet of the pump. And we set the control
05:29:560Jacopo Vivian: that is able to change the speed so that
05:33:630Jacopo Vivian: the controller is changing the speed of the pump. In order to achieve this constant delta. P.
05:44:300Jacopo Vivian: What happens if the Delta P increases, it will reduce the speed.
05:53:90Jacopo Vivian: What happens if
05:55:910Jacopo Vivian: the if the Delta P is lower than the set point, it will increase the speed until we reach
06:04:470Jacopo Vivian: our set going to delta. P.
06:08:70Jacopo Vivian: Okay, so this is how it's the same.
06:22:240Jacopo Vivian: It's the same because we have a the bottom.
06:29:60Jacopo Vivian: and then we have all our system and then add audio lines.
06:38:870Jacopo Vivian: So if you measure the meta PIN here or yeah, right?
06:44:990Jacopo Vivian: Depending on where you place the, it's answers
06:50:400Jacopo Vivian: you have that the Delta P across the pump
06:54:860Jacopo Vivian: is the same of the Delta T, of the open, honest display.
07:02:60Jacopo Vivian: So the pressure loss is always so. It's not intuitive, but they always depend on the load.
07:14:850Jacopo Vivian: The Delta P depends on the load, but you can adapt
07:18:790Jacopo Vivian: the working point of the system of the flow circulating in the system by also acting on the pump
07:36:590Jacopo Vivian: when there is a when they incurred on the back.
07:41:370Jacopo Vivian: You mean, please go. Yeah.
07:43:530Jacopo Vivian: So we have already logged in.
07:45:950Jacopo Vivian: Yes, but
07:56:420Jacopo Vivian: this- this is the characteristic curve of the platform.
08:02:550Jacopo Vivian: Forget about this. This is a always the same localized pressure loss due to this curvature.
08:09:610Jacopo Vivian: But what I mean is that here you go to the terminal unit.
08:14:270Jacopo Vivian: And if this mean that if you had an elevator, imagine this is elevator
08:23:680Jacopo Vivian: with the parastatic bomb that will close what happens from- from productivity. To continue, if you had more stock.
08:40:149Jacopo Vivian: this has really occurred with go like this.
08:46:130Jacopo Vivian: So if you don't change the speed. What happens is that your new rate will not move from A to B,
08:55:350Jacopo Vivian: okay.
08:56:279Jacopo Vivian: And of course the segment for other funkoids.
09:01:640Jacopo Vivian: If you have 100 employees and 50 of them
09:07:439Jacopo Vivian: stop because it's too hot in that moment.
09:12:800Jacopo Vivian: So the thermostat in the room decide that this phone point
09:18:649Jacopo Vivian: is not letting the flow circulate through it.
09:25:620Jacopo Vivian: Okay, then you will have a change of the characteristic of the old land.
09:34:550Jacopo Vivian: Oh, wow!
09:36:410Jacopo Vivian: And B is the new position. So what I'm saying is that for big systems, of course, this is not very much relevant for one of our.
09:45:729Jacopo Vivian: But if you have big systems.
09:48:779Jacopo Vivian: This is very important, because you can save them quite a lot of energy by stacking a good
09:59:790Jacopo Vivian: control to the pump, so that when the load is decreasing. You don't consume the same electricity
10:13:30Jacopo Vivian: that that you consume less electricity by reducing the the speed of the pump, and then I will make an example.
10:21:950Jacopo Vivian: You can also have a different controller of the pump of the circulation pumper.
10:30:770Jacopo Vivian: This is another example.
10:34:560Jacopo Vivian: By the way, I, when I will talk about district heating. I will show you exactly this program
10:42:240Jacopo Vivian: for the district heating system of Verona.
10:45:990Jacopo Vivian: because we have the data of that system, and they have a similar
10:51:980Jacopo Vivian: a similar behavior. So they set
10:56:540Jacopo Vivian: the main pumps of the whole district heating network.
11:00:850Jacopo Vivian: serving all the buildings in the city center of Verona
11:05:540Jacopo Vivian: with a similar control curve for their main separation pubs, so that when the buildings has less
11:15:250Jacopo Vivian: hitting him because outside is warm, ma'am, the circulation partner don't consume
11:25:10Jacopo Vivian: the electricity that would be needed to operate a point B, but they consume less electricity.
11:34:810Jacopo Vivian: Why? Because you switch the position.
11:39:610Jacopo Vivian: Imagine them okay,
11:55:280Jacopo Vivian: to understand these numbers.
12:04:130Jacopo Vivian: Okay, yes. So.
12:09:810Jacopo Vivian: okay. H. Is the Delta P in meter, supporter column.
12:15:780Jacopo Vivian: and the queue is the the flow. Okay?
12:20:670Jacopo Vivian: So in point A, you are beer.
12:27:680Jacopo Vivian: Okay, where my pointer is.
12:30:350Jacopo Vivian: So you have 55 cubic meter per hour
12:35:220Jacopo Vivian: and 11.5 meter supporter column of Pump Head.
12:42:650Jacopo Vivian: So you're pampered, and the and the efficiency here.
12:48:70Jacopo Vivian: it's on the ease efficiency line close to 75%. You see here.
12:56:110Jacopo Vivian: Okay, assume this is your design point in this design point you, your pump, will consume 2.3 kilowatt.
13:07:550Jacopo Vivian: Okay, no.
13:11:270Jacopo Vivian: I'm just using that.
13:15:200Jacopo Vivian: This this formula here where Delta Z is H.
13:24:370Jacopo Vivian: And then I divide by the efficiency because we have seen that we convert
13:29:660Jacopo Vivian: electrical energy into mechanical energy, and then we need to transmit this mechanical energy to the fluid to increase its pressure.
13:38:430Jacopo Vivian: So 75%.
13:41:940Jacopo Vivian: What happens if I leave?
13:45:440Jacopo Vivian: If I don't change the speed.
13:48:40Jacopo Vivian: if they don't change the speed there and the and then the load is requiring less
14:02:420Jacopo Vivian: flow because some bots are closed. I will switch to that position where my pointer is now.
14:10:550Jacopo Vivian: Okay, so 40%. Sorry, 40 cubic meters per hour.
14:17:50Jacopo Vivian: Okay, on the red dashed line.
14:19:640Jacopo Vivian: And in this case we are on the user efficiency line of 70%.
14:28:630Jacopo Vivian: So the head is, it should be higher to be honest. So
14:39:00Jacopo Vivian: the head should be around 13.
14:43:880Jacopo Vivian: So you have the that using, okay? I think some.
15:03:350Jacopo Vivian: Okay.
15:04:740Jacopo Vivian: So
15:13:50Jacopo Vivian: the new operating point would be here.
15:16:730Jacopo Vivian: But if we change the speed there with constant, with constant Delta P,
15:24:260Jacopo Vivian: we go here. So we are able to save it. 22% of electricity.
15:33:220Jacopo Vivian: If we use the the other control curve that I showed before
15:39:120Jacopo Vivian: we are able to reduce the
15:42:70Jacopo Vivian: electrical power by 41%, which is not March or all the links, maybe
15:54:910Jacopo Vivian: because all buildings and in old buildings the requirement for pumps is
16:03:740Jacopo Vivian: negligible with respect to the overall energy demand of the building.
16:10:220Jacopo Vivian: but especially for new buildings and refurbished buildings.
16:15:100Jacopo Vivian: Auxiliary systems like circulation pumps, are important. So, having a good regulation of the pump is important to achieve
16:26:700Jacopo Vivian: a well and efficient system.
16:31:530Jacopo Vivian: Do we have any questions?
16:34:960Jacopo Vivian: Because otherwise I change the topic.
16:39:860Jacopo Vivian: And the last topic of today is balancing. The so
16:46:120Jacopo Vivian: balancing, as we said at the beginning is, then
16:52:790Jacopo Vivian: it's not regular, does not refer to regulating the system at partial load. It refers to distributing
17:03:100Jacopo Vivian: the heat or the cooling according to the design
17:09:260Jacopo Vivian: values for each part of the building. Okay?
17:14:830Jacopo Vivian: And we said that in general, we could have this problem with the 2 pack systems with direct return.
17:22:960Jacopo Vivian: because we have the summer
17:25:870Jacopo Vivian: pressure losses along the lines that make the Delta P. Between this point and this point, lower compared to the Delta P, between this point and this point.
17:38:420Jacopo Vivian: So in normal condition, in this system, here, we would have more flow compared to this browser here.
17:49:290Jacopo Vivian: So we said that one way to counteract this problem is to have a reverse return. So in this case.
17:59:660Jacopo Vivian: we we counteract the balancing issue when then already in the design phase.
18:12:340Jacopo Vivian: But when okay?
18:20:295Jacopo Vivian: So this is an example.
18:24:270Jacopo Vivian: it's the same of before. So we have 2 risers, and in the left you see that?
18:38:790Jacopo Vivian: There are no balancing balances.
18:42:880Jacopo Vivian: Oh, yes, in the so balancing valves are used to
18:49:830Jacopo Vivian: to solve this problem when we don't have the reverse return. Okay?
18:55:170Jacopo Vivian: So if we have 2 branches of the system with different delta P. But they should have the same flow.
19:03:260Jacopo Vivian: We need to do something, otherwise we would have here
19:07:940Jacopo Vivian: more flow to the branch with higher delta. P.
19:12:210Jacopo Vivian: Okay.
19:13:600Jacopo Vivian: So in order to do it, we use a balancing valves.
19:18:60Jacopo Vivian: So we place a valve in this case. It's on the return of the 2 risers.
19:25:310Jacopo Vivian: Okay? So that we introduce some
19:30:610Jacopo Vivian: additional delta. P, so that the overall delta p. Between the 2 branches is the same.
19:39:250Jacopo Vivian: This is the working principle, and in this case, we are balancing the Delta P between the 2 risers.
19:47:770Jacopo Vivian: Okay, in this case we are balancing the Delta P between the 4 front points for each riser.
20:00:70Jacopo Vivian: because normally.
20:02:100Jacopo Vivian: in the closest riser, we have a higher Delta P, so normally in this phone call, we would have a higher mass flow rate compared to this phone call.
20:13:530Jacopo Vivian: which has a higher Delta P compared to this and to this, and so on.
20:18:260Jacopo Vivian: So with this additional pressure drop. So we compensate this difference, and we make sure that all these
20:28:270Jacopo Vivian: phone calls have the desired flow rate.
20:35:380Jacopo Vivian: Okay, so
20:42:760Jacopo Vivian: the operating principle is that the we regulate the flow rate of the medium pricing
20:54:330Jacopo Vivian: the through the balancing board
20:58:290Jacopo Vivian: by using a knob. Okay, that govern the movement of an obturator to regulate the slope.
21:07:740Jacopo Vivian: Okay. And now I will. I will show how it works.
21:14:170Jacopo Vivian: Basically, we are changing the Delta P across the bulk.
21:18:890Jacopo Vivian: Okay, so we are adapting the Delta P across the valve to reach the desired floor.
21:31:380Jacopo Vivian: We talk about the static and dynamic balancing because, basically dynamic balancing volunteer hot.
21:47:550Jacopo Vivian: that work with variable flow systems.
21:53:750Jacopo Vivian: Okay, as simple as that.
21:57:580Jacopo Vivian: So if you have a constant flow system, you use static balancing valve.
22:03:300Jacopo Vivian: If you have variable flow system, you user dynamic balance.
22:11:709Jacopo Vivian: This is how they are designed. So you can see, you can see that in 2 cases with plans connection, and we threaded connection.
22:22:640Jacopo Vivian: Go ahead.
22:26:570Jacopo Vivian: So this is the this is the obturator.
22:32:970Jacopo Vivian: And here we measure the Delta P across the valve.
22:38:110Jacopo Vivian: You see here the 2 piezometric collections here and here.
22:44:570Jacopo Vivian: Okay?
22:45:660Jacopo Vivian: And according to this Delta P, you change the position of this operator
22:52:980Jacopo Vivian: to make sure that the desired flow will cut off the bottom.
22:59:960Jacopo Vivian: Here you can see how it works. You connect alright
23:06:510Jacopo Vivian: in order to to commission the the system you connect to the 2 isometric connection, you measure the Delta P. And you regulate the number
23:17:920Jacopo Vivian: accordingly. Okay, how like this?
23:24:430Jacopo Vivian: So if I measure, for example, 14 Kilo Pascal at the 2 geometric connections here.
23:32:00Jacopo Vivian: and I want to achieve 900 liters per hour.
23:39:680Jacopo Vivian: How should I calibrate this valve?
23:43:100Jacopo Vivian: I take the chart of the balancing valve, which is this chart? Here
23:50:280Jacopo Vivian: I take that as the fee that I measure.
23:53:330Jacopo Vivian: So I I am on this, for example, line until I find that design flow rate.
24:02:00Jacopo Vivian: which is 900 liters per hour is 0 point 9 cubic meter per hour. So I reach this point.
24:09:630Jacopo Vivian: In this point I am not between
24:14:290Jacopo Vivian: the position 2 and the position 2.5.
24:22:930Jacopo Vivian: So you see that the Oh, you will
24:29:700Jacopo Vivian: turn up the Nobel until you find a position which is between those 2 positions, and there you will make sure that the exactly 900 liters per hour will cross this valve.
24:46:900Jacopo Vivian: Of course you can also use the same correlations that we have seen before.
24:55:630Jacopo Vivian: so you can either do it graphically, like I showed, or you can calculate, the Kv.
25:03:370Jacopo Vivian: And I use this table here.
25:06:780Jacopo Vivian: In this case.
25:08:470Jacopo Vivian: You have the Delta P. That you measure from the there's a metric connections.
25:15:920Jacopo Vivian: Is this one
25:17:520Jacopo Vivian: the desired flow rate is this one you calculate the Kv. And if from the Kv, you will find something like 2 point.
25:26:50Jacopo Vivian: So I'm thinking, and you achieve the same result.
25:30:370Jacopo Vivian: Okay.
25:35:200Jacopo Vivian: okay, so this is a week worker to change the position
25:41:280Jacopo Vivian: of then other ones you have there the value.
25:47:550Jacopo Vivian: I showed it with the chart, but it's the same if you do it with the phone line.
26:00:70Jacopo Vivian: So this is an example
26:05:200Jacopo Vivian: of a mix involved on the return line.
26:11:770Jacopo Vivian: Okay?
26:13:540Jacopo Vivian: And you can have that balancing valve on the supply under on the bypass.
26:25:300Jacopo Vivian: This is just the an example.
26:31:110Jacopo Vivian: Then you have dynamic balancing ballistic
26:35:310Jacopo Vivian: that are able, instead of you adjusting the number to the desired position.
26:43:110Jacopo Vivian: This will be made automatically by spring inside it, the number that will regulate the
26:55:890Jacopo Vivian: the obstruction to the water, so that you are always able, at the same flow rate.
27:07:160Jacopo Vivian: Of course it does not work always.
27:13:270Jacopo Vivian: It works for a certain range of Delta P.
27:17:270Jacopo Vivian: So for dynamic balancing valves, you need to set the desired curator right.
27:28:980Jacopo Vivian: and also to check that, you always operate between the minimum and maximum delta. P.
27:42:180Jacopo Vivian: Yeah. Hi reported summer.
27:51:00Jacopo Vivian: For examples of dynamic violence involved the automatic flow rate regulator and then independent regulator.
28:03:560Jacopo Vivian: Okay, but it's not important. Just keep in mind that you have either static or dynamic bouncing.
28:11:740Jacopo Vivian: the static balancing. You are responsible to calibrate the the position
28:21:446Jacopo Vivian: of the of the valve and in the automatic balancing that, of course, in the sorry. In the dynamic balancing
28:28:630Jacopo Vivian: you are. You need to select the the flow rate and check the the range of Delta P,
28:40:360Jacopo Vivian: and finally, this is useful for the report card.
28:47:900Jacopo Vivian: When you have difference, different flow rates in parallel.
28:56:740Jacopo Vivian: which is the case for your but I will cease that you need to do.
29:04:110Jacopo Vivian: calculate the so-called balancing flow rate.
29:09:460Jacopo Vivian: So in your case you have different rooms.
29:18:370Jacopo Vivian: You have the kitchen, the living room, the bedroom, and so on.
29:23:990Jacopo Vivian: Supply and the curriculum from the other system.
29:30:310Jacopo Vivian: So you have a manageable okay, that will.
29:42:950Jacopo Vivian: We have seen with the the horizontal, distribute the 2 pipe systems with horizontal distribution.
29:51:240Jacopo Vivian: We have many phones typically that distribute the different lines of in your case, your apartment, okay?
30:03:820Jacopo Vivian: And from your excel file when you you. I don't know if you already started doing the the exercise.
30:12:730Jacopo Vivian: but when you select the characteristic of the audience system for each room.
30:20:330Jacopo Vivian: you have a result in terms of flow rate.
30:24:600Jacopo Vivian: Right? You, said the Delta T.
30:27:800Jacopo Vivian: And and you said that the spacing and well, that's the number of circuits
30:41:30Jacopo Vivian: and some other parameters right?
30:44:40Jacopo Vivian: And you get as a result, it does not mean
30:49:70Jacopo Vivian: right that should be in a certain range.
30:53:250Jacopo Vivian: We said that not exceeding 3 meters of water column.
31:00:510Jacopo Vivian: Okay, battery is closer to one as a rule of thumb.
31:06:400Jacopo Vivian: But the point is that in the reality all these systems are connected to the same microphone.
31:15:290Jacopo Vivian: And therefore all these systems have the same.
31:21:640Jacopo Vivian: There's a p because they are connected to the same point.
31:27:270Jacopo Vivian: Okay, so the Delta P that you get from your calculation
31:32:330Jacopo Vivian: is not the Delta P that you have in practice.
31:36:250Jacopo Vivian: So you need to change the flow rate that will go to each this time I call them.
31:49:950Jacopo Vivian: and this is, of course, the same, because it's very, and so that the
32:00:600Jacopo Vivian: the Delta P is the same.
32:04:280Jacopo Vivian: Oh, this will be here.
32:09:340Jacopo Vivian: You get a certain level of fee from your excel. File.
32:18:330Jacopo Vivian: the pricing of their assistant.
32:26:340Jacopo Vivian: and admin that is a fee of for each group for a woman type. Okay?
32:35:610Jacopo Vivian: 27.
32:37:480Jacopo Vivian: I don't know so. But then we said that the Delta P must be the same for all the
32:46:640Jacopo Vivian: secrets, because they are connected to the same point.
32:51:150Jacopo Vivian: So you can choose the average, the lowest or the highest. It's your choice you already knew.
33:00:480Jacopo Vivian: and you will get a new?
33:05:110Jacopo Vivian: No? Right?
33:07:900Jacopo Vivian: Okay.
33:17:140Jacopo Vivian: We didn't know 1 14.
33:32:930Jacopo Vivian: Why do we have a 0 point 5 here?
33:36:640Jacopo Vivian: Because we know that Delta P
33:39:440Jacopo Vivian: is a function of the square of the plot.
33:43:240Jacopo Vivian: So here it's just the reverse, a relationship.
33:49:335Jacopo Vivian: So this is the one calculated from. Excel.
33:57:460Jacopo Vivian: Okay, this is the original. No rate that you have.
34:03:570Jacopo Vivian: And we see that that's a piece of the collector.
34:07:670Jacopo Vivian: So the data field of the collector is the one inspected
34:13:180Jacopo Vivian: will be the same for all the rooms you can choose. For example, the maximum
34:22:470Jacopo Vivian: between all the license fees.
34:25:470Jacopo Vivian: I of all the rooms.
34:30:20Jacopo Vivian: Is that clear?
34:32:950Jacopo Vivian: Or should I repeat it.
34:38:700Jacopo Vivian: Yes, yes, that's why in the slide you find engaging.
34:50:670Jacopo Vivian: because you, if you express it as meters of what they're calling, we call it 8, if you express it in, we call it Delta P. But it's the same thing.
35:01:710Jacopo Vivian: So we should pay a good designer the maximum value
35:08:810Jacopo Vivian: email all the meetings, and then design it
35:15:360Jacopo Vivian: with that pressure difference which refers to the Delta P. Between the supply and the return of the money.
35:24:110Jacopo Vivian: I will upload the
35:32:580Jacopo Vivian: I will upload the exercise to be done for the final report for this part. But basically you need to size
35:42:670Jacopo Vivian: and a 3 way a 3 way valve.
35:48:570Jacopo Vivian: That is a upstream of the manifolds.
35:53:320Jacopo Vivian: Okay, so I will just upload the instructions.
36:01:140Jacopo Vivian: and then you will have also other lectures with me about the generation units.
36:08:720Jacopo Vivian: so we will. We will also talk about it, and we will also. I will set another question and answer meeting about this part
36:18:820Jacopo Vivian: so that the you wouldn't.
36:23:880Jacopo Vivian: You will see better in the next week. Okay, I remember that on Monday you will have lecture
36:34:650Jacopo Vivian: with Professor Decarli about pooling systems pulling about shitlers
36:40:360Jacopo Vivian: because you need this topic to understand better understanding about data centers on Tuesday.
36:49:660Jacopo Vivian: and then I will come back on Wednesday next week.
36:54:400Jacopo Vivian: and we go on with the generation path.
36:58:160Jacopo Vivian: Okay, that's it for today.