Nuts and Bolts of Dairy Ventilation [Video] ▶️

0:04
Welcome and thank you for joining us today for this month’s University of Wisconsin Division of Extension’s Badger Dairy Insight, a monthly webinar series offered on the third Tuesday of each month.

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Badger Dairy Insight provides the latest research, dairy based information to improve animal welfare, breeding and genetic selection, automation and modernization, and nutritional decisions for producers, dairy workers and managers, and agricultural professionals.

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My name is Steph Plaster, business development outreach specialist with the Extension Farm Management program.

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I am your host for the session and I work closely with the Dairy program on emerging technologies.

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In this webinar, we will dive into dairy ventilation design with practical strategies for efficiency, heat abatement, and smart fan selection complemented by an interactive decision tool.

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Please add any questions or comments in the Q&A button at the bottom of your screen during today’s webinar.

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This is being recorded and you can find it on our dairy website in about one to two weeks and we will also feature it in our monthly Dairy E newsletter.

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If you’d like to re watch or share.

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Our speakers today are Doctor Nesli Akdeniz, assistant professor and extension specialist in Biological Systems engineering.

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Her research and extension interests include dairy building, dairy building and ventilation design, air quality and emissions monitoring, and heat stress mitigation, with an emphasis on developing practical decision making tools that help produce users improve productivity and energy efficiency.

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She also teaches renewable energy systems,

1:32
, a course cross listed with the Nelson Institute.

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We will also hear from Doctor Mario Mondaca, a senior technical application and research engineer at VES Artex and a leading expert in dairy barns, ventilation, heat stress abatement and facility design.

1:46
He specializes in analyzing the thermal environment inside dairy housing to optimize herd comfort and farm efficiency.

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With that, I will hand it over to Nesli.

1:57
All right, thank you, Stephanie.

1:59
There’s a technical difficulty here, so I will go ahead and share my screen one more time.

2:15
All right, sorry about that.

2:17
So thank you for the introduction.

2:19
I appreciate Steph for being here and for introducing us.

2:24
So the World Cup is here, so we can feel like the summer is here.

2:28
So the heat is here.

2:30
So we will talk about one of the mitigation strategies.

2:34
We will dive into nuts and bolts of the dairy ventilation design today.

2:39
So and we have a new app, new phone app and I would like to introduce that one.

2:45
Take this chance and then have a look at it.

2:50
All right, so this is the app.

2:52
So if you go ahead and just search dairy ventilation, so it is available both in the Apple Store and if you’re in Android user, you can search it and in Google Play.

3:06
So I have a QR code here.

3:08
If you can go ahead and scan the QR code, so it will take you to the correct direction.

3:14
So probably technical people already know this.

3:18
This is an endless process.

3:20
So this is something that I’m very new in this area.

3:23
So this is something that I am learning.

3:25
This is the first app that I developed by myself without any technical help.

3:30
So it is an endless process.

3:32
So we are already in the fifth version.

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So you need to download the 1.0.5, the fifth version of the app and then we want to keep improving this app.

3:44
So if you have any feedback, please let me know all right, so I like starting my presentation showing this slide.

3:52
So it does show us if it really matters or not.

3:56
So we know it stresses a problem, right?

3:59
And then, but is it a problem in Wisconsin? Right.

4:04
So this is a northern state.

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We have cold winters.

4:08
How about in summers?

4:09
Do we really need to worry about heat stress in cows?

4:13
So here we see the data and each time I show the slide I updated.

4:19
So today is June 16th, so it is just beginning of the summer.

4:24
So we already had one danger and seven alert dates for heat stress in dairy cows I’m talking about.

4:33
So on average we have 25 days of severe heat stress in Wisconsin, in southern part of Wisconsin and 5.6 days of very severe heat stress.

4:46
So it is a problem, it is a concern in Wisconsin.

4:53
All right.

4:53
So one way of or the most common way of handling heat stress is buying more ventilation fans and installing them and then you know, run those fans, right.

5:05
But choosing the right fan is very, very important.

5:09
And when we are choosing the right fan, there are a couple of things that we need to pay attention and one of them is the fan efficiency.

5:19
So Please remember we are talking about ventilation fans, right?

5:24
If you are using exhaust fans, we are working at a negative pressure, right?

5:29
Our static pressure is never 0.

5:33
So we are looking at numbers like usually it’s kind of on the lower side of .05 or .1 and we are looking at fan efficiencies at that static pressure.

5:46
So here, for example, on this slide, you see some fan efficiencies, right?

5:50
You see like 24, 21, 19, 16.

5:54
So sometimes people ask me, OK, we understand fan efficiency is important, but what is a good number, right to be able to answer that question?

6:06
We did this study what we did.

6:09
So if you’re familiar with BESS lab, BESS lab is a lab in Illinois.

6:14
And they are the, they are the lab, they are testing the fans that are available in the market.

6:21
So that’s kind of one of those, you know, official labs that test the agricultural ventilation fans and we looked at their records from 2015 to 2025 and calculated some average numbers to be able to answer your question about the fan efficiency.

6:42
So we looked at the upper range, we looked at what’s the like the average number and we looked at the lower range and we looked at those numbers at varying static pressures.

6:54
And this study was published.

6:57
So again, there’s a QR code here.

6:59
It’s an Open Access paper.

7:01
So if you would like to read more about this study, it is also available.

7:08
All right, so these tools are available like if you google go.wisc.edu/coolfans or google go.wisc.edu/coolfansSI.

7:19
So if you like SI unit, it is also available in SI unit.

7:24
So these tools are also available in the app.

7:27
So we will use this app to combine all our ventilation tools together.

7:32
So I will show you an example.

7:35
But one of the tools you will see is this graph.

7:39
So you will be able to choose your fan size.

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For example, if you are showing using a 60 inch fan, you can choose 60 inch fan and then go ahead and enter your fan efficiency values.

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So here the green line is the average, the upper range we see and we see the lower range.

8:02
So where are you standing at?

8:05
Are you like, is this fan better than the other fans that are available in the market or is this fan is kind of like within the lower range of the fan efficiencies that are available in the market?

8:19
So it’s stable.

8:20
We are able to do it all right.

8:24
So this is another data from that paper.

8:28
What we found is actually we already knew it, but the bigger the fan, the more efficient.

8:34
So the bigger the better, but there are some we need to consider

8:40
a couple of things before people are going and buying the biggest fan available.

8:44
So one of them is, is it a variable speed fan, right?

8:49
So we design our ventilation design for summer, but we also need these ventilation fans in winter, right?

8:58
So maybe in summer we are talking about 68 exchanges per hour.

9:03
In winter we are considering maybe only four air exchanges per hour.

9:08
So to be able to reduce from 60 to 4, we need to shut down some of our fans.

9:14
And if you are running only one fan in winter, we will not have an even airflow distribution, right?

9:21
So it needs to be a variable speed fan.

9:24
We need to be able to run reasonable number of fans even in winter.

9:29
So we have an even airflow distribution.

9:33
And then another thing that we really need to consider, this is kind of like the limitation when we are buying fans is, is there enough wall space to install those fans, right?

9:45
If you’re thinking to buy a very big fan.

9:47
And then if there isn’t enough wall space, since you will have your garage doors, other doors.

9:54
So if there isn’t enough wall space, then you may want to choose another size of fan.

10:03
All right, So I kind of show this graph.

10:06
So it’s really depends on the fan.

10:09
So what we know in general is fans are not really efficient if you use them at 100% capacity, right?

10:19
Just like we cannot drive a car at 100% capacity, we don’t want to run our fans at 100% capacity.

10:28
If we do, then the fan efficiency goes down.

10:32
But what capacity should be worked at, It’s really depends on the fan.

10:39
So the data we gather together shows us that 85% capacity is the place that you know that we get the maximum efficiency.

10:51
But it really depends.

10:52
There are some fans in the market like as you lower the capacity from 100% to 90, 80, 75, 60, as you lower the efficiency goes up.

11:05
But in general, the data was all over the place.

11:08
But if we want to give a magic number, I will say 85%, but I’m, I need to emphasize that it doesn’t apply for all fans.

11:19
The best way to decide it is to check the BESS lab report.

11:26
All right, so let’s have a look at an example.

11:29
So, all right, Steph, can you help me?

11:56
Did that follow me?

11:59
I am now seeing the ventilation calculator.

12:02
All right, so this is the online version of the app.

12:05
When you go to the app, you will see the same stuff there too.

12:09
So at the bottom you will see different tabs.

12:12
So one of them is the THI tab, adapting tab, evaluation, fan efficiency, payback and about.

12:21
So we are going to go through by the go through them 1 by 1.

12:25
So first of all, the first of all, we will look at the THI tab.

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So you have the option to say use my location.

12:35
So hopefully it will work OK.

12:38
So it will use your location to get Your local weather data and then you can say calculate THI today’s a beautiful day.

12:48
So our THI is low.

12:50
So it is like almost no stress or very, very mild heat stress day.

12:56
But if assume that it is a warmer day, right?

13:00
And it’s like about the rain, we feel the humidity, right?

13:04
So let’s say it is kind of like humidity inside, then it will give us the severe stress warning.

13:12
So we put a couple of actions here like they’re very simple actions.

13:16
We just turn on your fans.

13:18
You already know of them, but we just wanted to add a couple of notes to be able to grab your attention.

13:26
And then another tab is adopting.

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So it’s it is called adopting.

13:32
And the assumption there is you’re adopting a mechanical ventilation system.

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Either you’re building a new building or retrofitting an existing building or you’re switching from natural ventilation to mechanical ventilation.

13:48
So I already showed this tool in my previous presentations, but while we are here.

13:53
I want to just quickly show it without taking too much time.

13:58
So you enter your barn dimensions.

14:00
So we separated it as the southern part of Wisconsin, which is warmer and then central or northern part of Wisconsin, we assume the climate there is a little bit cooler.

14:13
So we entered the our building dimensions, number of cows, the targeted air exchange rate.

14:22
So we can enter 60 or if you want to lower it, we can enter a number like 15.

14:28
And then the fan capacity, let’s assume this is a little bit bigger fan and we entered the fan price and fan efficiency.

14:37
So what we have from the BESS lab report and we just say calculate and it will calculate us how many fans we need.

14:47
So these are bigger fans.

14:48
So we only need 11 fans for this size of a dairy building.

14:53
And one thing that it will also calculate is the required inlet size.

14:59
So it is very, very important that we have enough air inlet otherwise our fans they have to work very hard to be able to pull that air through, right.

15:10
So we have the tendency to close those garage doors, but if you don’t have enough air inlet in summer, we need to keep those garage doors open.

15:20
Please keep that in mind.

15:22
And then we have the evaluating tab.

15:25
So here the assumption is you already have a mechanical ventilation system, you just want to test it.

15:35
So let’s again you enter your building dimensions, you can look at the southern part or central northern part.

15:43
It will only change the number of hours these fans will work during the, you know, especially spring and winter seasons.

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And then you enter all these numbers and then you say calculate.

15:56
So it will give you how many air exchanges you’re achieving using these fans.

16:02
So by using 17 fans, I’m achieving 56 air exchanges.

16:09
So it’s kind of close to the our targeted number 60.

16:14
So I will say this is an OK design and it will give you again the required inlet size, which you may want to go ahead and check, make your measurements and make sure you have enough air inlet.

16:29
All right, so let’s look at our new tab.

16:31
So this is the tab that you can choose your fan size, let’s say 48, 36, or 60.

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And then this is the our average range, the green line.

16:46
And then we see the upper range and we also see the lower range.

16:51
OK, so this is the data you will get from the BESS lab report, but I have it in front of me, so I will go ahead and enter these numbers so we can see.

17:03
So we should be able to see the graph too.

17:08
So you can see the star, right As I type, the star will come up.

17:22
So this is a real fan.

17:24
It is.

17:25
It does exist.

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I didn’t make up the data.

17:31
OK, so let’s look at the data now.

17:34
So this is a fan.

17:36
If you are working at the static pressure 0.5 or 0.1, this fan will perform better than most of the fans in the market.

17:46
So you see that star is, you know, even above the upper range.

17:51
So but as the static pressure increases, fan efficiency decreases, right?

17:56
This is the general trend.

17:58
So I would recommend this fan for a lower static pressure buildings.

18:04
So dairy buildings, the static pressure is not that high.

18:08
So this one will perform well in a dairy building.

18:12
But let’s look at another example.

18:15
Let’s change these numbers a little bit.

18:17
So I’m just trying to show that each fan is built differently and they have different ways of using.

18:46
OK, so now we have a different story, right?

18:49
So if you’re looking at lower static pressure values, so we can see this one is still doing well, right?

18:56
So it is still above the lower range, but like lower than the average values, right?

19:05
But as you increase the static pressure, the efficiency stays above the average range.

19:13
So this one will perform well at higher static pressures.

19:18
So based on the like compared to the other fans that are available in the market.

19:24
OK.

19:26
And then there’s this payback periods.

19:30
So OK, so we have we want to buy an efficient fan and we do understand it depends on the static pressure.

19:39
We do understand the bigger the fan, the more efficient it is.

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But at the same time we cannot buy the biggest fan that is available in the market.

19:49
There are some stuff that we need to consider like you know, what will happen to the winter ventilation, is there enough wall space, right.

20:00
But other than that, if you like the company, if it is an efficient fan, are we go ahead, are we going to go ahead and buy that fan?

20:08
It is one of the questions we always have in our mind, right So.

20:14
Again, it depends.

20:16
The answer is always, I think it depends.

20:19
So it depends on the initial cost of the fan.

20:22
Here we see an example.

20:24
So fan one we need, let’s say this is a high capacity fan and we need only four of fan one, 4 fans.

20:35
And then let’s assume cost per fan is $2000 and the warm capacity.

20:42
Warm capacity is like the capacity that we use when we use that fan in this summer, right?

20:49
So it’s just kind of like 100% capacity or 90% capacity.

20:54
And then we have a warm capacity efficiencies.

20:57
So when we use that fan at full capacity, what is the efficiency of that fan then?

21:04
Cool capacity.

21:05
So when it cools down during winter or during the transition seasons, so our capacity goes down.

21:13
But as the capacity goes down, efficiency goes up, right?

21:18
And then we have fan 2.

21:20
These are smaller fans.

21:22
So to be able to have the equal amount of air exchange, we need 9 of them.

21:28
But the cost also goes down, right?

21:30
They are smaller fans, so let’s assume the cost is $500 per fan.

21:36
But when you buy nine of them, it is still cheaper, right?

21:41
So like it, it costs about 4500.

21:44
The other one costs like 8000.

21:48
So again we have the warm capacity, warm efficiency.

21:52
So these are smaller fans, so efficiency goes down and then cool capacity like cool weather capacity and cool efficiency.

22:01
So when we say calculate it will calculate us how many years it takes to catch up, right.

22:08
So for the this is like 4.1 years of payback.

22:14
So although we buy the more expensive fan in four years or four years later, the electricity cost will be able to cover them initial purchasing cost.

22:29
But it’s not true all the time, right?

22:31
So let’s assume this second fan was a little bit more efficient fan.

22:37
So let’s increase these numbers and then we say calculate, see it doesn’t catch or there is no crossover in 10 years period.

22:51
So we prepared this calculator like considering the 10 year.

22:56
Payback.

22:58
So usually we use our ventilation funds longer than 10 years, but you know 10 year is a good number when we are thinking about our financial investments.

23:09
So in this case, I will just go with the lower initial cost.

23:16
So I will buy the smaller fans and I will pay back pay less since the payback periods, you know they don’t crossover in the following ten years.

23:28
So yes, one efficiency to initial cost of that fan.

23:33
And of course there are other things that you need to consider like the service, the brand name, the reliability of the company.

23:41
All of them come together when we are deciding which brand we should choose.

23:46
And our last step is about tab.

23:49
So you can find our information here.

23:52
So the references, again, our publication is here.

23:56
You can just go ahead and click that link.

24:00
Hey, Nesli, we did actually have one question come in and the question is, does this tool only work in Wisconsin or can it work across the US?

24:10
And if it does work across the US, how do you change the barn location?

24:14
So it is an excellent question.

24:16
I, I, I was hoping someone asks this question actually.

24:20
So the way it works, number of fans, it works everywhere.

24:26
So it doesn’t matter.

24:28
We choose the location to be able to calculate the cost, I mean the monthly cost.

24:35
So if you’re going to build a dairy building somewhere other than Wisconsin and if the climate is very different, then you can just use the tool to calculate number of fans you’re required here in that size.

24:50
But the we calculate the cost like monthly cost, electricity cost of that fan considering Wisconsin day weather data, historical Wisconsin weather data.

25:01
So how many hours it needs to work in one year depends on our local weather data.

25:08
So yes, they can still use the tool, but it will be a little bit more limited to use.

25:15
Did I answer the question?

25:17
Yes, thank you.

25:19
All right, so I want to save a little bit time for Mario.

25:23
I know he has an excellent presentation.

25:26
And then just show my final slides.

25:42
All right, so we find the correct fan, right?

25:46
We purchased the correct fan.

25:47
And the most important thing to get ready for summer, I say this one in all my presentations, please keep those fans clean.

25:56
If you don’t clean, clean them, it doesn’t work.

26:00
It doesn’t matter which fan we choose.

26:02
So there’s a very high correlation between keeping the fans clean and the efficiency of the fan.

26:09
And be safe when you’re doing that one.

26:12
If you are using pusher fans, basket fans, make sure you adjust them so they’re heading toward the animals.

26:19
So when they are first installed, they are heading to animals, but then, you know they keep moving.

26:24
So make sure you check them on a regular basis.

26:28
And please, please make sure you have enough air inlets.

26:32
So don’t close that garage door, OK?

26:35
So make your calculations and then let us know if you want us to come and make some measurements and calculations for you.

26:44
If you don’t have enough inlet size, please keep your garage doors open.

26:49
And this is my last slide.

26:51
Again, I have the QR code.

26:52
Please go ahead and download.

26:54
And if you have any comments, questions, please let me know.

26:58
That’s all I have, and I will stop sharing.

27:01
Nesli, we did have one more question come in for you.

27:05
So do these calculations take into account the water nozzles installed on the fans?

27:11
There’s this question specifically from Saudi Arabia.

27:13
They need to install water nozzles on fans to cool the air.

27:16
And has this been considered in the calculation?

27:19
So this is the yeah, thank you for the question.

27:22
I understand that this kind of part of the heat stress management strategy, right?

27:26
We have the soakers, we have the ventilation fans, this tool focuses on the ventilation fans.

27:33
So we didn’t take the soakers or misters into calculation yes, but it’s an excellent point.

27:40
We should also start working on that one.

27:42
So thanks.

27:55
I assume that means I’m up.

28:04
Oh, thank you very much for having me.

28:07
I’m, I’m very excited that we’re able to have a academic and industry presentation at the same time.

28:12
I’m, I think that’s some of the strongest ways we can go about this.

28:18
And I’m, I’m going to present more or less what Doctor Nesli presented.

28:23
But from the industry side, it’s, it’s, this is really like how the sausage is made kind of presentation of how we design systems on BSR that I’m giving you some examples of the industry considerations to what Dr Nestle presented.

28:38
My name is Doctor Mario Mondaca.

28:41
I worked at the well I did my post doc and my PhD at the University of Wisconsin Madison, where I work at the Dairyland Initiative developing ventilation assessment methodology as well as formalizing the ventilation recommendations.

28:57
Funny enough, that got me a job in the ventilation industry where I, I continue doing essentially serving as half knowledge expert, half extension where I’m, I’m diffusing knowledge and outreach and making sure to bridge the gap between the industry and the academic world as as we’re doing right now.

29:19
One thing that I really want to bring up is this idea of a product efficiency versus a system efficiency.

29:26
A lot of the research right now on dairy systems are very focused on product efficiency and if you go to most rebate programs, they’re very focused on a product number.

29:37
A couple have started switching towards more custom rebates.

29:41
They where they actually look at the whole system because they’re starting to see the power, particularly in the variable frequency drives as as Doctor Nesli mentioned that slowing the fan down has a lot of benefits.

29:51
So we’ll go through a real system, look at the fan schedules and how all of that is set up and what difference it makes in the final calculation.

30:00
Because the microclimate of the cows is actually very different from what we see.

30:05
This is an extreme example.

30:07
This is an example of a New Zealand dairy and it’s a holding yard.

30:11
So it’s a grazing system.

30:12
So the cows are eating out grass on the fields, but when they have to be milked, they, they’re brought into one of these holding yards that are actually extremely hot.

30:22
So if you did just an analysis of the local weather, you’d see, oh, there’s very little heat stress.

30:27
We’re only getting to mild heat stress ranges, but the reality is that these holding yards are creating 2 to 4 hours every day of 40 plus or 140°F or higher.

30:39
There’s no ventilation, no cooling other than some sprinkling.

30:42
So what the cow is seeing what’s happening on the barn is is very different from what’s happening on the local weather station data.

30:52
And we’ll see an example of that with a more traditional system.

30:57
So this is a very large cross ventilated barn that we designed.

31:05
It is about 1500 feet long, 500 feet wide.

31:10
And a quick refresher, cross ventilation means the air is flowing perpendicular to the feed lane.

31:16
So it’s flowing across the cows of the bodies of the cows.

31:21
Tunnel is when it flows parallel.

31:24
So in this case it’s flowing perpendicular to the feed lane under 18,000,000 cubic feet of barn volume.

31:35
As a refresher, we in the winter we’re trying to maintain air quality both the the parts per millions of pollutants and moisture.

31:44
And as it gets hotter than ventilation starts to maintain the temperature in the barn up to a maximum practical ventilation rate typically dictated by the wall space on on the building.

31:57
And as as Doctor Nesli mentioned, most systems are running at full capacity by the time they reach 68 Fahrenheit.

32:07
That’s a relatively conservative operating point because if you look at the THI calculation, you’ll be at 68 THI at 100% humidity at 68 Fahrenheit.

32:20
Though some research is starting to show the high, very high producing cows could benefit from being cooled at 65 Fahrenheit or even lower.

32:30
But then the typical ventilation key performance indicators is correlating the total airflow to the barn volume, the cross-sectional area and the animals.

32:43
So we’ll always look at all three of them when designing a system.

32:47
Typically we aim for 40 to 60 area changes in the summer 1200 to 1500 CFM per cow.

32:55
And then air speed is more of a evaluating the the expected pressure of the barn.

33:02
So we’re more focused actually on what the cows are experiencing.

33:06
So we want a minimum cooling airspeed where the cows are laying down of 1 meter per second, ideally closer to 2 to 4.

33:13
And then in some extreme conditions where it’s extremely hot, some of our producers have reported that they prefer getting even higher air speeds to really maximize the cooling for these really large barn.

33:29
If we run our our KPI tool, which is just a quick way to calculate the these values, they’re going to house 8000 cows in there.

33:41
So we went for a design where the fans are running at 90% speed to kind of show what the the benefits that Doctor Nesli is about on this example.

33:52
And you can see we’re getting 35 air changes per hour, which is a little bit below the recommended value.

33:58
But because we have the 1300 CFM per cow, we’re still within within a good design range.

34:06
And then the airspeed is actually being improved with circulation fans in this system.

34:11
So that’s why the there is no baffle in this crossbarn where they normally would be a baffle.

34:19
This is the fan that we have for that system put in Doctor Nesli’s tool. 1 limitation right now with BESS lab is that their chamber, their AMCA 210 chamber cannot test fans larger than 60 inch.

34:34
So we, we actually had to build our own AMCA 210 chamber to, to get this data because our, our fan 72 inch fans and our 80 inch fans can’t be measured in BESS lab.

34:45
But as you can see, it’s, it’s, it’s really focused on being a very reliable product and making sure it can handle those, those higher pressures whenever there’s gusts of winds or any, any issues from the local weather, while still providing high efficiencies at the lower operating ranges.

35:05
So then I compared that fan against itself if it was running as a single speed fan with no VFD to really highlight the effects of how much just the VFD is doing.

35:18
So using the same fan, removing all the VFD components and and and assuming a simpler installation, we can see that that fan would have about a 5.8 return period.

35:36
Compared to the VFD version.

35:41
So I like this tool because it’s very visual and it gives you a really quick answer and at the end of the day, it it achieves the same outcome as what we would say that there is value in this more expensive fan.

35:55
There’s a couple tweaks you have to make on the cool cap to to make it match that.

36:00
You have to divide the total CFM by the number of fans.

36:04
The the biggest difference is the 6 month seasonal split that it’s assuming that the fans are running in their warm session for six months and in their cool session for six months, whereas we do a more annual analysis for the full year.

36:25
The reason for that is the today’s technology on controls is actually very advanced in dairy barns.

36:32
There’s there’s a lot going under the hood.

36:35
We’re not just switching relays on and off anymore to get a good idea for how the system will perform.

36:42
We go through the weather analysis.

36:45
We’ll look at the performance of the fan at all the operating points, not just the the summer and winter.

36:52
And we see how it’s interacting with any other potential cooling technologies that are installed in that system so that we’re planning to install.

37:01
So here’s a breakdown of temperature ranges in that area for for that large barn.

37:09
So you seeing 10 years of data to average to average the operating ranges.

37:16
We see that the summer it’s going to be about 22% of the year.

37:21
The winter is going to be about 25% of the year.

37:23
And then the remaining 53% is going to be in a transitional period where the fans are somewhere between winter and summer.

37:35
We get this data, there’s four different sources we like to use.

37:40
ASOS is a network of airports that publish their data publicly through the University of.

37:51
I’m going to get it wrong, so I’m not going to say it.

37:53
I think I’m pretty sure it’s Iowa, but yeah. IEMRE,

37:58
NASA Power and Upper Meteo are model based weather data, so they interpolate between locations and create full coverage.

38:08
So it gives you better, more localized data, but it’s model data.

38:11
But at the end of the day, they’re all, as you can see from the graph, they’re all very similar.

38:16
And because we’re comparing systems, errors will cancel each other out when you’re making this comparison.

38:22
So any of them, it’s a, it’s a good candidate.

38:25
If you have an ASOS network nearby, it’s usually your better option.

38:29
And there’s other more advanced paid services.

38:32
I just listed the free ones in case anyone is interested in starting developing this stuff.

38:39
Fan staging is how you’re going to operate the fan throughout the year.

38:43
This is our most basic method of just having a linear ramp.

38:47
So we said when the fan’s going to turn on, at what temperature the fan’s going to turn on, at what speed the fan’s going to turn on, when the fan’s going to start speeding up and then at what temperature that fan needs to be at full speed.

39:01
So that that really gives you the control to run fans in a specific way to maintain that efficiency for as long as possible and then start to increase it as you need the the extra capacity of the fan.

39:16
We always do also a one of these outputs for the sites where we, this is a specific ASOS network and we get again temperature ranges.

39:27
So we get a sense of how the the year is in terms of heat stress.

39:32
Then we also get a these buckets of the heat stress ranges.

39:37
So this area does reach the severe range.

39:40
So we would recommend a more aggressive cooling to try and, and reduce that.

39:46
And then there’s quite a bit of the of the heat stress is also moderate.

39:51
So lot of reasons to use a a cooling system in this in this solution.

39:58
And then as we’re staging these fans, we want to maintain even fan distribution.

40:02
And as Doctor Nesli mentioned, we want to make sure the inlet makes sense, how the curtains are going to operate, how the positive pressure fans are going to operate and to increase that ventilation in a controlled manner and maintain those KPIs throughout the year.

40:16
Now all of that together looks something like this.

40:18
You you can review this table at your own leisure, but the main thing is.

40:25
We want to see that efficiency and how that efficiency is moving throughout the year, how the CFM and the KPIs are moving throughout the year.

40:33
Make sure we have all that narrowed down.

40:35
And then I, I purposely extended the 60 to 80 to 68 to show that linear ramp and how the fan is going from its winter mode and then starting to, to ramp down to its ramp up to it’s summer mode and how that’s affecting the overall performance on the KP is.

40:57
So if we compare that analysis of the 10 year weather data average now that really highlights the benefits of the VFDs, that payback period

41:08
is closer to about 2.5 break even for the the single speed fan versus the VFD fan.

41:19
However, this is not an analysis I would expect the average person to, you know, pull out of their pockets.

41:25
We are working on making this analysis more available to the public, but I just want you to be aware that particularly with VFDs and variable speed fans, there’s a lot of of benefit that is gained by looking at the full year of weather data.

41:44
But how truly representative are those local weather stations?

41:49
There really isn’t a lot of research on how the barn is performing compared to its local weather station.

41:56
We do have some data and I am, I want to show you some of those what that looks like.

42:03
So this this, this barn that I mentioned, it is actually running right now.

42:06
So this is an output of its inside temperature.

42:10
There’s 9 temperature sensors in their distributed and, and this this would be the average of all nine.

42:17
And then this blue line would be the local weather station that’s about 20 miles away, I think.

42:23
So there’s about a 20 minute lag in the weather, which is kind of funny to watch because I guess the weather takes about 20 minutes to get to the barn.

42:34
Very similar peaks, and if I shift that temperature and zoom in a bit, you can see the barn is more or less matching the environment.

42:44
Except when it gets really cold at night.

42:47
The barn staying about 10° warmer and it’s really avoiding, it’s never dipping into that 32 freezing range and making sure the barn’s staying cool enough to avoid freezing while still providing the proper ventilation needed during the winter.

43:07
And then if we go towards the hotter edge in May and the beginnings of June, it’s actually cooler than the outside.

43:15
You can see some of these peaks don’t match and that’s because this barn has a high pressure fogging system.

43:22
So it’s actually maintaining about 10 to 15° cooler and the highest peak of the local weather station because that high pressure fogging is cooling the air as it’s entering the barn and as it’s distributing.

43:41
So there is a significant uncertainty.

43:43
There’s both a, a difference in total temperature as well as a difference in, in timing, right.

43:50
There’s a bit of a lag in the in the data, but when you’re making a product to product comparison, a local weather station is still your best available option.

43:59
Statistically speaking.

44:03
The the cooling system is changing that as well.

44:07
So it’s reducing the peak temperatures.

44:11
If our staging had something operating at 80° like some of the sprinkler systems do, for example, in this one, it would never turn on because we never reached that temperature.

44:22
So, so we have to be mindful of how those, how the cooling systems are affecting the environment and how that’s going to affect our operating ranges because we reduced that, that moderate heat stress range down to a mild and, and we have to make sure we’re aware of that.

44:39
And it gives us the power to potentially slow down ventilation and get those efficiencies.

44:46
Because Doctor, Doctor Nesli’s research actually that 85% payback period.

44:52
They found that in a model, they found that if you use the a supplemental cooling that you could have similar temperature results.

45:02
So, so we’re really focused on on developing those enhanced controls coupled with cooling systems.

45:10
But we really think that’s the the future for getting even more efficiency out of the system rather than further tweaking fans and and trying to get it out of just the fans themselves on a more technical side, on the fan side.

45:29
So where do you get this data?

45:31
As Doctor Nesli mentioned, BESS Lab is probably the most publicly available data for fan information.

45:40
It does both the AMCA 210 which is exhaust fan testing as well as the AMCA 230 standard which is circulation fan testing.

45:47
The panel fans or the the fans you see over the cows rather than on the side wall.

45:54
There are accredited AMCA labs.

45:57
AMCA is the air movement association that manages this testing standard.

46:03
So you you can become an accredited testing lab through their system, but not all of those labs publicize their data or make it available for 3rd party to testing.

46:15
So which is why BESS lab is so popular.

46:18
Actually, manufacturers will also have their own methodology or they’ll have in like in our case, their own AMCA testing facility.

46:26
So there’s also the MAEDBS.

46:31
It’s a database in started by California and we’ll get into that in the next slide.

46:39
Fan testing is required now.

46:42
20 years ago we said it was the Wild West, right?

46:46
But now it’s a it’s a requirement by both California Title 20 and the Department of Energy test procedure for fans and blowers.

46:55
So if you want to sell a fan that meets the recommendations for Title 20, it has to be listed in the California database, which will have its full data set that the Dr. Nesli presented as well as some other values that are required by Title 20.

47:14
And then the Department of Energy requires any representation including marketing of energy efficiency or energy consumption of the fan.

47:24
Again, Asterix if if it meets certain descriptions to be based on either one of the AMCA test,  BESS lab or an equivalent test.

47:36
So we are a lot more complete on as far as what is being enforced on testing and and anyone that’s publishing these values should be able to present you of how those values were achieved and and and tested and and so that we can have a fair comparison between fans.

48:01
There are two efficiency numbers.

48:03
One was developed by the AMCA which is called the Fan Energy Index or the FEI.

48:11
It’s a ratio of what is considered a baseline fan and you should be more efficient than a baseline fan.

48:19
So it will compare your actual fan against that.

48:23
So any fan should be greater than one.

48:26
And then the N grade value, which is more of a European value for their their energy standards is different countries will have minimum efficiencies for the N grade value, which evaluates there’s very slight differences between the FEI and the N grade that don’t matter for the average user.

48:47
Both metrics will generally say whoever has a higher value will be more efficient for the most part similar to the VER or the CFM per one.

48:58
It’s just trying to condense it into a simpler number with a that has no unit so it’s easier to compare.

49:06
But again, they stop at the product level analysis beyond efficiency industry considerations.

49:13
This is things that we look at that you don’t typically see on the recommended CFM per watts or rebate agencies.

49:22
Air flow ratio, I really like Doctor Nesli’s graph because it it takes care of the air flow, air flow ratio consideration.

49:31
So air flow ratio is how much air you produce at .2 inches of pressure compared to point 0.5 inches of pressure.

49:40
So essentially how well can your fan handle higher pressures?

49:44
Well, the graph shows that perfectly, right?

49:46
So but if you if you needed a quick number, which back then that’s what all that was available to publish quickly, the airflow ratio gave you a really good idea and most systems would recommend .8.

49:59
That doesn’t mean the fan is bad if it has a low number, it just means it can handle higher pressure.

50:03
Some fans are designed specifically for high capacity at low pressures.

50:08
So they have a really bad AFR, but their job is not to handle pressure.

50:13
Their job is to move a lot of air in, in open systems, right?

50:16
So the amperage rating of the fan is something I don’t typically see discussed, but it’s something that’s very important.

50:24
This will this relates to how long the motor health will be on that fan.

50:30
You can find a couple of samples of BESS lab test that are overamping the motor, which means the the motor is running at higher amp capacities that it should typically you should match this value or if they have a service factor higher than one, then it should be like if this was 1.2 you could go 20% higher than that amperage rating, right?

50:54
So ideally you shouldn’t be operating the fan at this range because you’re you’re beyond what the motors rated for.

51:01
But if you know your system will never reach those pressures right then, then you can operate that fan at that higher capacity.

51:08
So something to keep in mind when you’re looking at at the fans, the realities of having very large systems installed.

51:17
Some of these, I mean that that barn I just showed had 264 fans.

51:21
So the weight becomes an issue, the space becomes an issue.

51:26
Like Doctor Nesli said, very large fans maybe more efficient, but efficiency only looking at the CFM per Watt.

51:33
If you have a 15 foot each side wall, you cant  put two 80 inch fans on top of each other.

51:39
So you’ve severely limited the amount of of fans that can fit because of that side wall choice.

51:45
Well, now you need to go to smaller fans like 72 or 60 inch and the 84 each won’t be able to deliver as much CFM that it could.

51:54
We’ve seen barns, especially on retrofits where total power’s an issue.

51:58
They they only have so many kilowatts to to provide.

52:01
So you have to go with either smaller fans or more efficient fans issues when your budget or your loan has a hard cap.

52:09
So even if a more efficient would would pay itself back, you can’t afford it, right?

52:15
And that’s where rebate programs really help bridge the gaps and then availability.

52:19
You you can’t always get every fan in every region and especially summer comes lead times can get very long.

52:26
So we typically recommend to start designing your summer system in the winter so that you can get ahead of all of that.

52:36
The the standard of AMCA 230 and this efficiency numbers measure how much energy efficiency the fan provides.

52:43
But specifically AMCA 230 I think misses the ball on what the cow actually needs, which is that velocity at the cow level.

52:51
We’ve used the, the mapping that I developed at the Dairyland looking at 5 minute averages because it’s the more statistically sound amount to look at how that air is actually distributed from that fan.

53:06
So we actually have a better idea of how to space the fan and we it makes it a lot easier to compare different fans of different sizes because now we know that how the airspeed is developing at those distances.

53:19
So a 55 inch is actually more expensive than a 72 inch because you actually have to double the number of fans to match the airspeed.

53:27
So it’s something that would really are pushing beyond what’s currently published in the standards and that will really help under make you understand the system a lot better.

53:38
So fan efficiency and this individual performance numbers are really good reference.

53:43
However, more and more we’re seeing the the evaluation to shift to system efficiency so and enhance control with really high it’s really going to highlight that particularly as it’s being paired with the new cooling systems and and how they can modify fan operation together.

54:04
OK.

54:05
With that, I think that’s it. Thanks so much, Mario.

54:13
I don’t see any questions that have come in yet.

54:15
So Nesli actually would like to say or add one more thing before we end.

54:20
So that will give folks a chance to ask any of those last minute questions before we have closing comments.

54:26
Nesli gonna go ahead.

54:27
Yeah, thank you Steph.

54:28
So Mario, I really enjoyed your presentation.

54:31
Thank you.

54:32
That was a very good one.

54:33
So I your presentation just reminded me one thing when I was, you know, listening to you.

54:40
So it is very difficult to evaluate 1 fan, right.

54:44
So we have to look at the whole ventilation system and the reason like I wanted to clarify this one.

54:50
The reason we picked up like, you know, we assume ventilation fans work like 6 months in winter, more than six months in summer month is since we never know, farmer may just turn off that fan, right?

55:07
So or that fan may be working at 70% capacity in winter or, you know, we never know how the adjustment is unless we know the whole ventilation system.

55:19
So we have to make that, you know, assumption to be able to simplify things a little bit.

55:25
And Steph reminded me one good point too.

55:27
So the app is available in many countries.

55:30
I cannot say the number from the top of my head, but I believe it is available for in more than 170 countries.

55:39
So worldwide available.

55:41
So Yep, thank you.

55:44
All right, thanks so much, Nestle and Mario, really appreciate you being here with us.

55:49
Join us next month folks on July 21st for strategies to reduce methane emissions on dairy farms where we discuss tackling methane where it starts from storage to solution, exploring practical farm ready manure strategies that balance cost, performance and real world impacts.

56:05
So you can register at go.wisc.edu/badgerdairy.

56:09
And actually we did have a question just come in.

56:12
So this question is for both of you.

56:14
What is the the biggest misunderstanding that dairy producers in the Upper Midwest have when it comes to ventilation?

56:26
I can go ahead and ask that again.

56:27
So the biggest misunderstanding you think dairy producers in the Upper Midwest have when it’s coming to dairy or when it’s coming to ventilation?

56:35
So yeah, I I can go first.

56:37
So I emphasize it a couple of times not having enough air inlets and then they feel like they need to close those garage doors to not to have a short circuit.

56:48
So yes, it is important.

56:50
If it is tunnel ventilated building, if you open the garage door then we will aerate the feed alley only right.

56:58
So the the air flow will not go inside the stalls.

57:03
So we want to aerate there too, but at the same time we need to have enough air inlet if we don’t have enough air inlets, you know, maybe even having less number of fans would be more helpful than having more number of fans.

57:17
So we need to calculate our air inlet.

57:20
And now there are those curtain, you know, openings kind of on the short wall, short end of the building.

57:28
So we need to have enough air in there.

57:30
So I cannot emphasize it enough, I guess.

57:32
Yeah, very similar.

57:36
Yeah, I think in from my experience, not just in the upper Midwest, but anywhere where it gets cold, I think one of the biggest misunderstandings is not having enough air in the winter.

57:46
There’s a lot of fear that you’ll hurt the animals or that you’ll hurt the calves with the recommended four air changes per hour.

57:56
But for the most part, a well designed system will make sure that if you’re not cooling the animal directly or or the the sensitive animal directly, but if you don’t provide that ventilation, then the really bad stuff builds up and it creates a lot of health issues.

58:12
So I think really helping people understand that it’s safe to ventilate in the winter and it’s necessary.

58:19
I think that would be one of the biggest confusion areas that I’ve seen.

58:27
Thank you and thanks for the really great questions today, folks.

58:31
You have just one more minute to get any of those last minute questions.

58:34
And as you see on the screen, if you’re interested in more and additional information, unbiased university based dairy resources, please visit our Extension Dairy program on the web at dairy.extension.wisc.edu.

58:49
You can also find us on Facebook at Extension Agriculture.

58:52
Thank you so much for participating today.

58:55
Thank you, Mario and Nestle for being with with us and we hope you’ll join us July 21st for those strategies to reduce methane emissions on dairy farms.