Trascrizione
00:01:230Michele De Carli: Okay. So
00:06:680Michele De Carli: oh, I forgot. All right. So we are going to
00:14:420Michele De Carli: start with the the first, st let's say topic which is the thermal comfort.
00:22:554Michele De Carli: So we are going to see the the parameters that affected the thermal comfort, and how we can define the indoor conditions for the thermal comfort.
00:37:990Michele De Carli: Thermal comfort is part of the so called indoor environmental quality which may, which takes into account that the thermal comfort the indoor air quality
00:49:770Michele De Carli: the acoustics and the visible comfort we won't talk about acoustics and and the visible comfort while we were talking, especially on thermal comfort and indoor air quality. If you are interested in acoustics there is a course applied acoustics made by the 1st sort developed.
01:14:830Michele De Carli: It is on the personalized adapter.
01:17:439Michele De Carli: If you are instead interested in the lighting the visual comfort daylighting these topics are, instead of held up by Professor Fiorent in the course of electrical engineering.
01:35:254Michele De Carli: Okay, so let's start. So we are going to see 1st of all, thermal comfort. And then once we finish the thermal comfort, we move into the air core indoor quality for defining the proper
01:50:510Michele De Carli: flow rate of air supply in the river.
01:54:270Michele De Carli: So what is, what is thermal comfort? Okay? So I have to thank Professor for this slide because he's basically his idea. Okay, so basically, he's I feel good. Okay? So I just inserted an additional into here.
02:14:505Michele De Carli: You don't hear it. It's it doesn't matter. Okay.
02:17:920Michele De Carli: but it was the the the beginning of James Brown song. So, by the way, yesterday was another song of James Brown. Okay, but yes. So basically is feeling good in a certain where, of course, in a certain okay.
02:37:410Michele De Carli: so we will see what feeling good being in thermal comfort is.
02:44:410Michele De Carli: And basically, this is what we are going to see. Okay in in terms of, let's say topics. So we are going to see. 1st of all, we are going to analyze the physics behind the thermal comfort. So that means the energy balance of a person, and how the person and the room and environment are exchanging heat. We are going to see, then, how to
03:13:630Michele De Carli: how this approach has been transferred into corporate parameters by thanks to the Tanya is a professor
03:27:410Michele De Carli: special working from, let's say, the seventies to the beginning, 2,000 in Dtu, in Denmark.
03:36:170Michele De Carli: And then we are going to see some and this is everything related to the so-called global comfort means interaction between the human body and the room. Okay, as a whole. But as we will see. For the for designing Hvac systems. We need also to take into account some special local discomfort conditions which are which are called localized thermal discomfort.
04:06:625Michele De Carli: So this localized thermal discomfort. We see that they will. Oh, sorry.
04:11:400Michele De Carli: Okay, they will not. Really affect the the designing. Okay, so we will see that some parameters will not be really
04:24:992Michele De Carli: defined. Okay. Some limits in the in the the different systems that we are going to see are limited by this localized terminology.
04:37:60Michele De Carli: And then I will show you some some testing and the instrumentation how to measure thermal comfort. And then I will also explain you a little bit about
04:48:730Michele De Carli: some recent, relatively recent developments like the concept of the abdachment code.
04:55:390Michele De Carli: So what is. So let's start with by introducing the definition of
05:05:314Michele De Carli: so thermal comfort is you can see it's a a combination, let's say of 3. Okay? Or let's say, a combination of 2
05:18:430Michele De Carli: slash, 3 parameters.
05:21:480Michele De Carli: On one hand, we have to consider what is the let's say, the relationship between the human body and the room.
05:31:689Michele De Carli: So we need to take into account that we are in a certain
05:39:780Michele De Carli: environment, we would talk about, maybe indoor environments. Okay? Because that is where we are going to provide heating and cooling. So we are exchanging it into the environment. But of course.
05:53:660Michele De Carli: we are also doing some activity in the in the indoor environment. So we have to take into account also the physiological perspective. So also how the human body behaves. And also we have to take into account some psychological aspects. Because.
06:16:305Michele De Carli: we are, we could be in the same room in the same environment under the same conditions. But some of us can feel the room less or more comfortable, depending on its or her his psychological attitude.
06:37:663Michele De Carli: So
06:40:500Michele De Carli: as we see, we have. Let's say, consider both these aspects. On one hand, we have to consider the thermal balance between the human body and the room. We have to consider the physiological. So how and why we change our our let's say
07:06:260Michele De Carli: As we see we have a control, a camera control system. Okay, in the portal so, depending on the, on the, on the solicitations that we have from the from the from the indoor, from the from the surrounding environment. We react. Our body reacts in a in a in a certain way due to physiological aspects, and, on the other hand, we have some psychological aspect to take into account. Okay.
07:30:870Michele De Carli: we are going to see. So we freeze a little bit. This psychological aspect. We come to this point to that point later on. So now, what we are going to see is, let's say, what happens in, let's say in the human body, and
07:46:380Michele De Carli: most of all between the human body and the and the surrounding. Okay. So we start, we start focusing on the physiological. And let's say, physical aspect. Then we move into the psychological aspect. Okay, so what?
08:08:360Michele De Carli: we are we? As I told you yesterday, we work. We will deal with several
08:16:250Michele De Carli: standards. Okay, in this course.
08:19:370Michele De Carli: Luckily, we have a standard an international standard. You see, it's everything you and I and Iso, okay standard. So it's a worldwide use standard European level, but also national level on thermal comfort. And we have a similar
08:41:919Michele De Carli: Co standard, which is the Shai 55, which is more or less.
08:51:540Michele De Carli: In the same, let's say, or
08:55:410Michele De Carli: what is written, the shrine, 55 is more or less the same as written in 7, 7, 30, so there are slight differences between one and the other one.
09:05:580Michele De Carli: So why are we lucky to have this standard?
09:10:710Michele De Carli: Well, we are lucky because we know that when we design, when we size a system.
09:17:280Michele De Carli: as we see, we can fix some indoor temperature in winter and summer, and we know that, based on these standards.
09:27:890Michele De Carli: if we design properly the heating and cooling system, then, if someone will complain if we are in a certain range of temperatures. We can state that this
09:41:80Michele De Carli: range of temperature is suitable for comfort or is can be considered as comfortable environment. Okay.
09:51:112Michele De Carli: we come back to this point later. But what I want to emphasize is that having a standard, we have a as I told you yesterday, we have a reference, and we are sure that we can be safe for any complain about people. Of course, if we have reached the goal of having a comfort environment or comfortable environment.
10:17:110Michele De Carli: Okay, so now, what is
10:23:100Michele De Carli: but this, basically, this slide is summarizing or is listing all the all. What I have said before, okay, about the let's say, these 3 aspects to take into account so physiological, psychological, and thermal, and the and the thermal balance between the human body. So physical exchange between the human body and the humans.
10:45:940Michele De Carli: what about the physiological aspects? So so just I mean, the some basics. Okay, you know that we have
10:57:150Michele De Carli: our human body is more or less round about at 37 degrees C. Okay. And in order to have
11:06:950Michele De Carli: regulation of our of our body, which is mainly dealing with the the blood. Okay? So the the blood flow rate and the into the different parts of the of the body. Okay,
11:31:870Michele De Carli: is, related to the the comfort, the the feeling, the sensation, that we have with respect to the temperature. Here you can see the different circulation and the temperatures that we might have in case of cold conditions, or feeling cold and feeling warm. So you can see that when we probably
11:54:160Michele De Carli: experience that when you're feeling cold, your hands, your your feet. Okay, you're they are becoming cold. That is because you are. You have a Vaso constriction. Okay? Which means that the in the peripheral areas you try to have
12:13:484Michele De Carli: is is,
12:17:350Michele De Carli: is acting in a way that you are. You are trying to exchange less as less heat as or less heat as possible. In order to to limit the the.
12:30:890Michele De Carli: then
12:32:760Michele De Carli: the heat rate. Okay towards the outdoor environment. So feeling cold means that you have a bus restriction. So you're reducing the flow rate.
12:42:500Michele De Carli: Okay of the blood into the peripheral nervous.
12:46:850Michele De Carli: On the other hand, when you're feeling warm. Okay? Instead, you are trying to maximize the heat rate the heat flow. And that is done by the Basil dilatation. Okay? And by making the blood flowing at a greater rate
13:11:515Michele De Carli: into the peripheral areas so as to exchange more heat as possible. Okay? In order to to have to increase the heat exchange with the surroundings.
13:28:394Michele De Carli: So these are basically the 2, the 2 different. Let's say,
13:36:250Michele De Carli: behaviors. Okay, physiological behaviors that you might have. Okay? And of course, in extreme conditions, you might have shivering. Okay? And that will increase the by by having air into the into the
13:58:830Michele De Carli: when you're when you're shearing, you are increasing the muscle
14:03:390Michele De Carli: metabolism. Okay? So as to let's say, contact with the with the the outdoor cold environment. On the other hand, when you're feeling warm, you're sweating. And in that way you are releasing more heat. Okay, so you're you're increasing the heat
14:26:270Michele De Carli: exchange with the surround.
14:29:540Michele De Carli: All this stuff is so all the mechanisms the physiological mechanisms are are managed by the hypothalamus, who is which is sorry. The control organ of our body, which is balancing and regulating all the physiology and the physiology say the the comfort, the thermal comfort in the
14:59:590Michele De Carli: of the person.
15:02:490Michele De Carli: When could we say that we have? Okay. So now
15:13:80Michele De Carli: which is the physical, let's say, when we. So this is from the physiological point of view. Okay? So from the physiological point of view, this is how
15:22:980Michele De Carli: the human body works. Yes.
15:31:355Michele De Carli: yes, it's here.
15:40:170Michele De Carli: Okay. Now. The
15:49:140Michele De Carli: okay. So that is how it works. Now, what is which are the physical mechanism. So which is the the physical? How can we describe physically the
16:03:210Michele De Carli: the the the comfort condition. So in principle, we can. We can express the or we can make an energy balance an energy on, let's say, on an average, looking at a certain, you know, time, frame or
16:24:440Michele De Carli: working. Let's say, in the instantaneous power balance. Okay?
16:30:980Michele De Carli: And
16:36:670Michele De Carli: and
16:38:440Michele De Carli: in in this case, what you have to think about is that you have an energy input and an energy output. Okay? Or let's say, in in terms of instantaneous
16:53:101Michele De Carli: approach, you have a power input and a power output. Okay?
17:00:690Michele De Carli: And this should be balanced. Okay, so the input and the output should be balanced. What is the input and which are the output?
17:09:640Michele De Carli: Well, here you can see the energy balance written, let's say in a synthetic way, okay, so you have to think that each of these parameters can be read can be can be described. But at least one equation. Okay? So we have. We can in principle write a set of equation describing the power. The
17:34:490Michele De Carli: scenarios balance between the
17:38:730Michele De Carli: what do we get as input and what we get as on what we have as output.
17:44:120Michele De Carli: Basically, the input is the supposed energy metabolic rate. Okay, so metabolic rate is what we have is input okay in terms of energy input.
17:57:290Michele De Carli: we will see that what in detail, what we, what what it is so I will briefly introduce them. And then we see
18:04:823Michele De Carli: one by one, what we have. So basically, the the input is the support metabolic rate.
18:11:820Michele De Carli: And we have then, a list of output. Okay of outgoing energy
18:21:380Michele De Carli: or powerless way which are related to the external work that we are doing
18:31:210Michele De Carli: so, depending on the activity that we are doing.
18:34:822Michele De Carli: And then we have the heat analysis. So you can see we have the respiration losses. Okay? Which? Because when you breathe the air, you intate the air at lower temperature than our body, because our body is at 37 degrees. Okay? And of course, we breathe usually
18:58:590Michele De Carli: here with a certain vapor content. Okay? But in general, we are okay producing, we are emitting some vapor. Okay? So it's much more the vapor that we that we have that we
19:16:50Michele De Carli: release than the vapor that we get from from the respiration.
19:21:680Michele De Carli: By the way I make a
19:27:890Michele De Carli: I assume that you know perfectly. Okay, the psychometry. Okay. So if you don't know the psychometry, I will.
19:34:830Michele De Carli: I will leave basics of psychometry. Okay, but the psychometry, I will. I. We will see the the chart of the ushering. Okay, diagram for the temperature and the and the
19:49:201Michele De Carli: humidity ratio. Okay? So you have to know perfectly the background. Okay, I won't spend any.
19:56:970Michele De Carli: neither one. We need to explain anything about that, Cyclops. So I assume that you know very well that cyclot
20:04:670Michele De Carli: close the bracket. So we have respiration losses because of of the air intake, which is colder and drier than the than our lunch. Basically. And then we have. Some, let's say, heat losses.
20:26:460Michele De Carli: Okay, due to the due to convection, see?
20:32:980Michele De Carli: And infrared radiation. Okay, so we are. We are exchanging heat with the, with the external, which is the surrounding environment by convection here and by infrared radiation with all the surrounding surfaces.
20:49:390Michele De Carli: and we have then to take into account the heat loss due to the to the to the screens. Okay, so the latent loss
21:03:500Michele De Carli: that we have through the screen. Okay, by reflection. And of course, we have some losses
21:10:807Michele De Carli: due to the conduction that we have through our so depending on how much we are dressed. Okay, we can. We can have a greater or lower amount of heat that we are. That we are exchanging. Your. Your colleague was feeling cold. And now he put on his.
21:36:160Michele De Carli: what is this sweater?
21:39:666Michele De Carli: Okay, so all this stuff. Okay, we have to take into account. And of course, we are input minus output.
21:47:360Michele De Carli: And this is the energy storage. Okay? And as as we have seen, we have your balance. Okay, if we have more input than output, we are, we are storing energy. And if we have more output than input then we need.
22:04:500Michele De Carli: you need basically, okay, or we are consuming, and we are consuming our our storage energy. If we if any, okay, so what about then? The different the different some of this list of parameters. So let's start with the metabolic. So metabolic rate is basically a combination okay
22:31:270Michele De Carli: of of activities that we have. So basically most of the most of the
22:42:180Michele De Carli: the greatest part of the of the power that we have is due to the processing of food. Okay? So basically, we eat and drink in order to to transform food into energy at the end.
22:58:28Michele De Carli: But of course, we have also the transformation of oxygen into carbon dioxide. Okay, by breathing. Respiration and blood and blood flow. Okay.
23:09:984Michele De Carli: and of course we have some. Let's say some of the energy that we need is to replace okay, the or to regenerate the sensor and the organism. And then we have some, of course, psychological factions which are, let's say, some basic activity that we have. And of course.
23:32:50Michele De Carli: and another important topic is the activity that we do. So, it's different. If we are sleeping, or if you are listening, okay and concentrating yourself to listen to me. Or if you are watching the TV, or if you are doing if you are playing any sport. Okay, if you're running, if you're walking. So yeah, different possibilities, different activities.
23:57:620Michele De Carli: all the the. The. The combination of all these of all these activities is the metabolic rate.
24:07:450Michele De Carli: The metabolic rate is basically the the then and
24:16:450Michele De Carli: the combination of all these activities that we have just mentioned.
24:21:30Michele De Carli: And here, of course, you can see that it is, of course, different. The metabolic rate that we have, depending on the activity that we are doing so depending. If we are looking at
24:35:730Michele De Carli: overnight daytime, but also even during daytime, we have different activities. And what is important to say is that what we are interested in is the average activity of a person. Okay? So when we are
24:51:468Michele De Carli: when we want to check, which is the temperature that we have to set in a certain room, we have to take into account the average metabolic rate. So the average activity that the person on average can do in a certain in a certain environment.
25:11:683Michele De Carli: Okay, so basically, this is of course, the, as we have seen. Okay, the metabolic rate is strictly related to their physiological to the physiological aspects that we have seen. So
25:34:510Michele De Carli: by increasing the metabolic rate by increasing activity. We have seen that, basically, we are going to
25:44:350Michele De Carli: let's say, accelerate the metabolism of the person. And that means that basically, we will need basically more power to, let's say, release, but also to to have, as let's say, input in the body.
26:03:470Michele De Carli: No, the
26:06:870Michele De Carli: luckily. And that is why we need the standard. Okay, the metabolic rate is standardized. So we don't have to invent anything. Okay? But thanks to the studies done in the past
26:23:630Michele De Carli: 60 years ago.
26:25:676Michele De Carli: It has been possible to set some standardized metabolic rate. So some standardized activities.
26:33:280Michele De Carli: And, as you can see, we have
26:36:820Michele De Carli: a a unit which is called met. Okay, which is states for metabolic rate. And in that case, one met is
26:51:60Michele De Carli: the inactivity of 58 watts per square meter. So it's the average power.
26:59:130Michele De Carli: By what is what is the square meter that we have in the denominator is, let's say, the reference surface of a human body. So the human body, an average human body is a person okay of about one 80 m². So average person
27:22:810Michele De Carli: is has a standard surface of 1.8 m² which means that on average, is a person with 70 kg and a height of 1.7. Okay, so this is the average person. Okay.
27:44:490Michele De Carli: so you can see that if you're seated.
27:48:870Michele De Carli: you are. You are consuming one night. Okay, so you are consuming about 60 watts per square meter. Okay? So you have to multiply 60 by 1.8 in order to have, let's say the the. So 1.8 times 60 is more or less 100 watts.
28:09:320Michele De Carli: Okay? So the one Meg means more or less 100 Watts, delivered as or needed as power by the person average power consumed by a person.
28:21:852Michele De Carli: Of course, if you're if you're resting, you have a lower Td, so you can see, we have 0 point 8 met. Okay.
28:31:920Michele De Carli: if you are doing sport. Okay, the activity can increase. Okay, up to, let's say, format. If you're playing tennis or 8 match if you are running okay?
28:44:183Michele De Carli: So we have to consider which is the 5.th Okay, so
28:49:190Michele De Carli: you or the typical activity for an office is the so called the 7 connectivity. So the interactivity is
29:00:330Michele De Carli: in the standard is usually set as 1.2 mat. This is the activity that on average is done by the office or also your activity. Okay.
29:13:20Michele De Carli: my activity is slightly higher. Because I'm standing. I'm walking. Okay. I'm talking. So my activity is slightly greater than yours. Okay, but we are more or less the same in the range of 1.2. Meg, okay?
29:28:240Michele De Carli: So you can see the the standard the standard is providing the metabolic rate for different types of of
29:45:370Michele De Carli: oops
29:47:650Michele De Carli: of activities. Okay? So you can see. It's interesting. You can see there are also activities for the lakers. Okay, it was also comforting Bicos is
29:58:490Michele De Carli: something which can be in what is
30:02:620Michele De Carli: interesting. I don't know if you, some of you work in automotive, for instance, or in aircraft, but let's say that there are also these activities to take into account.
30:14:132Michele De Carli: So the starter has a list of different metabolic rates for the different activities.
30:21:60Michele De Carli: So that was the 1st parameter. Now, what about the other parameter? So we have seen. This is the, let's say, the activity. So the activity is related to
30:32:336Michele De Carli: the energy that or the power that we need. Okay to consider.
30:39:605Michele De Carli: Which is again, I would like to. Highlight is a mix of the activity of a person plus the the, the
30:48:400Michele De Carli: the input, that you get from the food. Okay?
30:52:373Michele De Carli: So this is what you have, as as let's say.
30:58:112Michele De Carli: power. Okay to of the human body.
31:02:360Michele De Carli: Now, what about the heat transfer? So what about the heat exchange between the human body and the surroundings?
31:12:531Michele De Carli: We said, we have some respiration. Okay, losses. Okay. So you can see, we have
31:23:629Michele De Carli: the the sensible.
31:31:900Michele De Carli: Okay, okay. And
31:38:530Michele De Carli: and Latin glasses. Okay, for the respiration. You can see that the these are, let's say,
31:49:190Michele De Carli: tens of Watts. Okay?
31:54:380Michele De Carli: Then we have. So we we said, we are due to the respiration. We have some heat losses. Okay, Latinent and sensible. We have convection with the air. We have April aggravation, and then we have to take into account also the type of clothing that we
32:11:680Michele De Carli: our lesson. Okay? So how can we consider all these this? these aspects. Okay? Let's start with the with the clothing. Okay, the clothing is also
32:33:550Michele De Carli: standardized. Okay? So we have. The clothing is a clothing resistance. Okay? So it's basically a thermal resistance which is expressed in square meter delving divided by what? Okay? So it's a resistance. So the power is in the denominator. What is the denominator? Square meter, again, is the
33:01:60Michele De Carli: surface of the human body 1.8 cm, and Kelvin is the temperature difference between the skin and the surrounding.
33:09:330Michele De Carli: Okay, so basically, this is the 10 month resistance.
33:18:500Michele De Carli: usually the in in usual environments we have between 0 point 5 and 1.5. We will see that later on. Okay, so the the clothing can be defined. And the way we can define a certain, let's say,
33:40:824Michele De Carli: the way describing the way we we dress more or less.
33:46:400Michele De Carli: Okay, now about the other losses. Okay, we can see that the
33:56:580Michele De Carli: we can. We can consider the losses due to convection and radiation. Okay? And the losses due to evaporation. Okay, so.
34:09:989Michele De Carli: how much are these losses shared? So are we losing more energy or more power
34:18:300Michele De Carli: in due to convection and radiation with the surroundings? Or are we losing more power due to the latent losses? Okay, due to the evaporation.
34:36:823Michele De Carli: It depends on the temperature that we are considering. You can see that the the lower the temperature, the greater the effect of the losses due to convection elevation. So let's say.
34:50:190Michele De Carli: through the external, between the the same
34:57:520Michele De Carli: be between our body and the surroundings. Okay, rather than sweetening or evaporation into the skin and into the lungs.
35:09:960Michele De Carli: And we are talking about. We will talk about moderate environments. Okay, I didn't mention that.
35:22:300Michele De Carli: Okay, but the the standards. 7, 7, 30 is that
35:31:250Michele De Carli: defining or defines the thermal comfort in modern environments means environment which are not cold or cool.
35:42:240Michele De Carli: Okay, we have standards also for warm environments. Okay, like, if you have a very huge okay,
35:53:550Michele De Carli: deep source. Okay.
35:56:221Michele De Carli: Imagine if you work outside in a sunny day, that is
36:01:400Michele De Carli: warm environment. Okay, extremely warm environment.
36:06:530Michele De Carli: And it's not even dealing with cold environments, with very cold environments like, I don't know if you are working in a refrigerator, in a dealing with the refrigerators. Okay
36:20:870Michele De Carli: in the in
36:25:250Michele De Carli: in the supermarket. Or if you're if you're storing the food in a in a, in a cold cell. Okay? Or so in that case, these are extremely cold environments. Okay, but we are usually moderate environments. So usually we are in the range between 16 and
36:44:910Michele De Carli: 30 degrees. And these are called moderate environments.
36:49:680Michele De Carli: Warm environments, extremely warm environments, moderate environments, extremely cold conditions. Okay?
36:56:462Michele De Carli: So we are more or less in this range here between, let's say, 16 and 2627. Okay? And you can see that in this environments. Okay, most of the most of the heat okay is basically is basically lost by convection and reduction. So what does it?
37:20:760Michele De Carli: It means that basically the infrared radiation with the surrounding surfaces and the convectively transfer with the air? Okay.
37:31:10Michele De Carli: is much more affecting the human buggy it exchange, then they lacking than the evaporation. Okay.
37:47:90Michele De Carli: In general, in these moderate environments, also briefing also the sensible loss due to briefing, is not that big? Okay? So we can in principle neglect it. Okay?
38:00:720Michele De Carli: And we can say that basically among the different
38:08:400Michele De Carli: this of heat exchanges that we can consider. We can, let's, say, concentrate our our effort on the heat loss between the external body. Okay, and the surrounding due to infrared radiation and conduction, and we can neglect in principle the
38:33:420Michele De Carli: the evaporation or the laptop to load.
38:38:980Michele De Carli: which means that practically in a moderate environment the relative humidity is not playing a big role in terms of temperature.
38:48:410Michele De Carli: And as a matter of fact, okay, thanks to the studies of of funders, we can say that in between, let's say, 30% and 70% of relative humidity.
38:59:730Michele De Carli: a a change in relative humidity is not playing a big role in terms of comfort perception. Okay, so we can say that among the different parameters in the environment we can in principle neglect. Okay, that relatively so, the relative humidity is not
39:20:250Michele De Carli: as important as the other parameters for the thermal. So basically the terminal, the relative humidity plays a minor. So the major role is played by the connection, so by the air, temperature, and infrared radiation. So the the temperatures of the different surfaces that we have in a certain
39:43:60Michele De Carli: what about clothing? Well, clothing is a little bit.
40:00:300Michele De Carli: because we have to take into account different different.
40:06:640Michele De Carli: a set of different parameters. You have to think about
40:24:400Michele De Carli: wet clothes or dry clothes. Okay, usually consider dry clothes. But this is also something that can be. And of course
40:35:340Michele De Carli: you are seeking. So you you can you, you have a thermal resistance. Okay, in your in part of your of your body.
40:46:440Michele De Carli: so you can see that a chair is is has an increase of the on the on the clothing. Resistance, I told you clothing resistance is
41:04:190Michele De Carli: expressed in one clue is
41:10:280Michele De Carli: 0 point 1 5 5 m² telling, divided by a okay?
41:17:981Michele De Carli: So what is the
41:23:400Michele De Carli: So you can see that? Considering a chair is an additional clothing resistance. So this is a clothing, resistance to add to your
41:37:210Michele De Carli: to the way you do this. Okay, in principle
41:42:625Michele De Carli: so which are the? I will skip this one here.
41:47:460Michele De Carli: But what is it?
42:11:140Michele De Carli: Yes, okay. So in winter, usually we dress more. We have more. We are.
42:21:310Michele De Carli: Kath sorry
42:27:270Michele De Carli: I made the post. I don't understand.
42:31:40Michele De Carli: Okay, sorry. Just a minute.
42:45:100Michele De Carli: See Browser.