Trascrizione
00:03:420Michele De Carli: Okay. So before starting.
00:07:570Michele De Carli: I wanted just to give you 2 advices. I will come back to these points tomorrow in more detail.
00:15:00Michele De Carli: Can you hear me? Nope.
00:16:630Michele De Carli: Yes.
00:19:702Michele De Carli: Okay. So the the 1st thing is that we are going to have a
00:26:880Michele De Carli: happening in 10 days from now with the
00:31:590Michele De Carli: project that we I'm dealing I'm managing is unizable. So on the 20th of
00:38:400Michele De Carli: March, which is next Thursday, not this Thursday, but
00:42:900Michele De Carli: next Thursday there is a kind of exposition in unison. Okay, I will let you know.
00:50:444Michele De Carli: You're warmly welcome to come there. Okay, this 1st point.
00:57:380Michele De Carli: The second point I will also let you know
01:02:100Michele De Carli: between tomorrow and and Wednesday. We are running from middle of beginning of April and
01:15:700Michele De Carli: a laboratory. Okay, which is called well, it's on urban energy models.
01:21:850Michele De Carli: And it is a volunteer based laboratory. So it it provides a an open page. The effort is more or less 3 cts. Okay, it's a different it's completely different from other courses that you have done so far. So it's let's say it's a kind of example
01:40:970Michele De Carli: experiment that we are that we are doing. Together with the other universities. There is the Technical University of Dresden, Technical University of Tallinn, and 2 Universities of Ukraine. Okay?
01:52:810Michele De Carli: And we are. And we are going to set up a a, a common laboratory for all students from all universities. Everything is in in online. Okay, it could be based in Internet. It's called, it's called collaborative
02:12:920Michele De Carli: Internet learning.
02:15:430Michele De Carli: Okay? So you have. It is, based on
02:21:850Michele De Carli: 6 to 7 weeks. Okay, every week. You have to perform a task together with the other colleagues from
02:29:880Michele De Carli: mainly from other universities. And at the end, you have to deliver a report. And and that's okay. So there are not frontal. There are not. Like,
02:45:90Michele De Carli: usual classes. Okay, lectures. So it is just learning by doing, okay, so we are going to set up the experiment this year, and from next year it will become an official laboratory with the 3 ects. Okay, so this is a kind of
03:07:410Michele De Carli: experiment that we are doing. Anyway, I will come back
03:11:683Michele De Carli: tomorrow or day after tomorrow with more info on this point to you.
03:20:830Michele De Carli: I'm going to send an email to both courses, to to Hvac, and also the previous course of energy. Yes.
03:29:970Michele De Carli: yeah. Okay.
03:32:150Michele De Carli: Good.
03:33:120Michele De Carli: Now.
03:34:230Michele De Carli: you left on. Okay? So I really want to go quite quick on these points. Okay, so we have seen. Yeah. Last time you have seen with Professor William the importance of.
03:49:990Michele De Carli: let's say, dramatic conditions. How many of you didn't do? The didn't take the course of the 1st semester and the business.
03:58:760Michele De Carli: No, you didn't do that. Okay.
04:02:950Michele De Carli: no worries. Okay, so
04:08:200Michele De Carli: I. As you have seen, we have design conditions, winter condition and and the summer conditions winter conditions are a strict, steady state condition without solar addition, and no internal gains
04:24:960Michele De Carli: in In the in the summer condition, we have to consider the fluctuation, and so the design, the the variable condition over the date.
04:41:148Michele De Carli: As we told you, we, this is to set up the power of the system. Okay? And then based on the power of the system. We design all the stuff.
04:52:239Michele De Carli: When you select the the system, the the heating and cooling system, the Hvac system. Anyway, you're responsible also on the energy which is required by the system, and in this case.
05:07:205Michele De Carli: there the there are. There are possibilities to calculate the heating and cooling demand of the building, which is, which means the energy required by the beginning. We are not going in detail on that, because that is mainly a focus of the 1st semester course. But what is important that you understand? Because we we consider these issues also.
05:33:348Michele De Carli: During the during, the course, is at least the so. The the concept of the
05:41:560Michele De Carli: degree day which, and among heating and cooling degree days heating degree days, so we can set up, let's say, a simplified evaluation of the energy required by the buildings in heating and cooling. By this parameter, which is called degree days.
05:59:937Michele De Carli: Usually the heating degree days are official data. Okay?
06:05:892Michele De Carli: So far, the cooling degree days, you can find definitions on them. But usually they're not really that much used. Okay. So while heating degree days are really are really
06:19:700Michele De Carli: are well established values and condition.
06:23:590Michele De Carli: What is this heating degree day so I will mainly. I will talk just on the heating degree. Okay, I will not talk about the cool degree day. The meaning is similar. Okay? But it's not. There is not a unique and official way to calculate that, anyway.
06:42:152Michele De Carli: What is the heating degree day? Well, basically, there is the you have to consider which
06:50:570Michele De Carli: is the average condition outside. So the temperature outside over, let's say one day, for instance.
06:58:680Michele De Carli: And so day by day, okay, in the so
07:04:470Michele De Carli: from the 1st of January to the 31st of December. Okay, you have to calculate the
07:11:580Michele De Carli: difference between the indoor temperature and the average outdoor temperature.
07:16:770Michele De Carli: What is this. This is, let's say, a measure to estimate, if
07:23:980Michele De Carli: if you need, and how much you need energy for keeping usually if the other temperature.
07:37:240Michele De Carli: the average order type of rupees
07:42:210Michele De Carli: or equal 12 degrees. Then it is recognized. Okay, it is a quite well established rule to say that you are. You need the heating. Okay? So if the outer temperature falls below 12 degrees, then you might say that you need heating in your house.
08:04:333Michele De Carli: So we said that the indoor temperature is 20 degrees.
08:12:160Michele De Carli: So what you have to say, what you have to do is to make the calculation between, let's say, the 90 degrees, which is the indoor temperature and the average ambient temperature.
08:23:890Michele De Carli: I'll go back to you.
08:28:960Michele De Carli: Okay, you consider this temperature difference only if the outer temperature falls below. Okay, 20 degrees.
08:42:400Michele De Carli: And then you can sum up all these differences. Okay, so this difference now is 0. If the outdoor temperature is above 12 degrees
08:53:328Michele De Carli: you can do this calculation, or you can also
08:57:620Michele De Carli: do in a much more in a much simpler way. You can calculate the and you get the same result you can consider not day by day they are the average outdoor temperature, but the mean monthly outdoor temperature.
09:16:790Michele De Carli: So you have to do just 12 calculations, and you have to set a code. If the outer temperature is below or above 12 degrees.
09:25:280Michele De Carli: and then you multiply this temperature difference bye, they
09:32:610Michele De Carli: number of days of the month. So in that case.
09:36:260Michele De Carli: for January you consider 1031, 28 for February 31st 31. I'm sorry for March
09:43:850Michele De Carli: 15 for April, because the heating is mandatory from middle of October to middle of April. Okay, so we have 181
09:52:330Michele De Carli: days for heating here in. Okay, then
09:56:750Michele De Carli: nothing until the half of September or October, then October again, 15 days, November 30 and 31 in December. Okay, so you can calculate the average out of 10.
10:10:390Michele De Carli: And the difference is what you get times the
10:14:510Michele De Carli: number of things. So what does it mean? So basically.
10:19:60Michele De Carli: what you get is a kind of integral of temperature difference between inside and outside. So that is the the the amount of energy that you need is somehow related to the to this figure to this degree day which is
10:40:260Michele De Carli: you can see here, this is a here you can see, reported the in the blue dots. Okay, the blue points. You have the
10:51:425Michele De Carli: daily energy sorry the daily temperatures, outer temperatures.
10:56:920Michele De Carli: The green one is a mean monthly temperature.
10:59:830Michele De Carli: The blue line represent the 12 degrees, which is the threshold.
11:03:750Michele De Carli: Okay, and the red line represents the inner temperature.
11:10:550Michele De Carli: So the 3 day is basically the area, the green area in between the
11:19:772Michele De Carli: between the red line of 20 degrees and the mean outer temperature. Okay?
11:29:340Michele De Carli: And this is a
11:32:850Michele De Carli: This is a a proportional okay to the amount of heating that you need in this location.
11:40:590Michele De Carli: So you might have a location where you can get a greater or lower degree days. Okay, just a minute.
11:52:760Michele De Carli: So
12:00:510Michele De Carli: now, for instance, if you have
12:07:400Michele De Carli: okay.
12:13:40Michele De Carli: if this is the if these are demands. Okay?
12:19:80Michele De Carli: And this is the temperature.
12:20:870Michele De Carli: Okay, we said, we have indoor temperature here 20 degrees.
12:27:980Michele De Carli: Okay?
12:29:100Michele De Carli: And we have the
12:30:900Michele De Carli: threshold temperature of, I will. Sorry. I will do it a little bit closer to the 20 degrees.
12:42:210Michele De Carli: This is the threshold temperature. Okay.
12:46:400Michele De Carli: so we might be in an orange climate. Which is this one here. The minimum temperature in the north atmosphere is
12:55:710Michele De Carli: January. Okay, so that is the average temperature that we have.
13:00:840Michele De Carli: So in the in the, in the sorry
13:06:880Michele De Carli: in the orange climate. Okay, the degree days or eating
13:11:890Michele De Carli: is represented by this area here.
13:16:720Michele De Carli: If we are in a colder climate. Okay, like the blue one.
13:21:320Michele De Carli: Then the average temperature outer will be lower.
13:26:760Michele De Carli: Okay?
13:27:910Michele De Carli: Which means that on one hand, we will have the, the, the, the.
13:36:60Michele De Carli: the crossing line between the blue planet and the 20 degrees day will happen.
13:44:150Michele De Carli: Later in in spring. Okay.
13:49:340Michele De Carli: and sooner in autumn. Okay, so that means that in a in a colder climate.
13:56:230Michele De Carli: We need the heating for a longer period of time than in a warmer climate. Okay.
14:03:20Michele De Carli: which is quite reasonable. And on the at the same time, we will have also a greater okay
14:11:626Michele De Carli: amount of energy, because the area in the degree d for heating for the in the blue climate. Okay.
14:23:300Michele De Carli: the integral between the 20 degrees and the blue line is greater than the integral. Okay of the of the orange area. Okay?
14:33:630Michele De Carli: So that means that the degree days for heating in the blue climate is greater than the degree days
14:41:10Michele De Carli: prohibiting in the orange cloud.
14:45:110Michele De Carli: So the colder the climate.
14:49:100Michele De Carli: the greater the degree days for heating. Okay, and having a greater 3 days for heating means that we will need more energy to eat. Okay, so we will see later on, either at the end of this lecture on
15:05:870Michele De Carli: next next lecture tomorrow. Okay, how we can use the degree days for heating, for calculating in a simple way the energy demand of the building. Okay.
15:18:810Michele De Carli: is it clear?
15:20:430Michele De Carli: Okay?
15:21:360Michele De Carli: So I just want to mention that this is the easiest way to calculate the energy demand for heating. We will use this this.
15:34:780Michele De Carli: this figure here to calculate the estimate.
15:39:550Michele De Carli: very rapid, the energy, the mentality. Okay.
15:43:734Michele De Carli: you have to remember that there are more detailed calculation. Okay, which are based on the average temperature month by month. Okay? Or even by, let's say, hourly conditions. Okay? So, considering the typical hourly profile that you might have okay over one. But this is, let's say, part of the 1st semester.
16:11:80Michele De Carli: Okay.
16:13:130Michele De Carli: about solar radiation. We do. We will not really go in detail. We will not consider really the solarization apart, the design condition for the design condition for cooling. We will consider clear sky condition in July. Okay? Which is the typical condition that you consider for the design. Of course.
16:41:570Michele De Carli: if you want to do energy analysis, and you want to consider the solar radiation, then you should consider the average condition of solar radiation in this location. Okay? But we are not really interested. Well, this is interesting. But in this course we are not really focusing on that, because this is more part of the 1st semester course. Okay?
17:08:579Michele De Carli: Okay. So just to summarize. Okay, what is important for you.
17:15:730Michele De Carli: Remember, we will talk about design condition, because these are the ones used for the design.
17:24:130Michele De Carli: Okay, so to size the heating and cooling plants. Okay.
17:29:54Michele De Carli: and of course, related to our choices, there will be
17:34:740Michele De Carli: also a related energy need for heating and cooling.
17:40:732Michele De Carli: We will very roughly and briefly look at this one here. We will not
17:49:130Michele De Carli: consider, and we will make some. Let's say, let's say draft.
17:53:640Michele De Carli: or I can tell you how to avoid, to
17:57:750Michele De Carli: to to have too much energy. Okay, consumption.
18:01:700Michele De Carli: But we are not ready to go in detail on the energy required for heating and cooling. Okay, that will be mostly, I mean, very roughly, and we will not really concentrate. But then we will mainly concentrate on the design and how to design how to size the heating equipment. Okay.
18:21:250Michele De Carli: okay, so I stop the recording and.