[00:00:00] Speaker A: Hello and welcome to the Consulting Specifying Engineer podcast. I'm your host Amara Roskas and today we are talking to Jeffrey Jewers about data center cooling, an all important topic for mechanical engineers. Thanks for joining me today, Jeffrey.
[00:00:17] Speaker B: Well, thank you.
[00:00:20] Speaker A: Excellent. Well, sustainability is a critical factor in data center design and engineers must now design systems that can optimize energy efficiency without evaporating water.
In this conversation, Jeffrey Jewers, engineer at Johnson Controls, will discuss the trends driving the need for water conservation and the associated equipment impact.
He will detail the types of economizers available for air cooled systems and their design trade offs and and then Jeffrey will share some best practices to help guide engineers in air cooled system design.
So before I get started, just a little bit of background. Jeffrey Jwers is a data center cooling subject matter expert at Johnson Controls.
Focused on sustainability and carbon neutrality goals of hyperscale customers and global collocation companies.
Jeffrey is focused on the data center vertical market to ensure widespread adoption of sustainable and innovative cooling solutions across multiple architectures and regions.
That's a lot. Jeffrey, sounds like you're busy.
[00:01:33] Speaker B: Oh Mara, thank you, thank you for hosting me today. And yeah, it's been a good, good 22 years now, so.
[00:01:39] Speaker A: Nice, nice.
So let's start like right at the top. What are some of the paradigm shifts impacting the data center industry?
[00:01:48] Speaker B: Oh, absolutely. There's a few different paradigm shifts that we're seeing in the industry right now.
One is these data center customers and owners are wholly getting away from consuming any type of water on site.
The second one that we're seeing is increased rack densities, meaning we're trying to put a lot more computing power and a lot more heat into a lot smaller spaces.
And that's facilitating the need for liquid cooling, which we're now seeing. Water brought all the way down to the chip level for cooling versus just doing an air cooled server as we were historically.
[00:02:31] Speaker A: Okay, so why are data center owners and operators shifting away from water cooled systems?
[00:02:38] Speaker B: So the water cooling has, when you look at a historic data center, much of the cooling and all the development data centers were evaporating water to meet their cooling. This was done via direct evaporation or it was done via evaporation to cool chiller equipment.
As data centers have gotten larger, evaporating water has become difficult for a few reasons. You're getting the geopolitical reasons. You want to be a good neighbor, you want good pressure.
In many locations and areas, water is a scarce resource and the abundance of water usage becomes a negative press for Your facility along those same lines is just fundamental availability of water. We do have locations around this globe where regardless of what press you're willing to accept, the water just is not available for evaporation.
And then probably the third is, which goes into both economics of the first two is your redundancy requirements, which for a data center that is trying to be online 24 hours a day, seven days a week, they need to make sure they have redundancy in all their systems. If your systems are relying on evaporation of water with the scale that they're building now, the feasibility of water storage to ride through a 24 hour event, or the feasibility of a second supply of water to meet your redundancy requirements becomes very difficult. So wholly for those three reasons, data centers are shifting away from evaporating water.
[00:04:21] Speaker A: On site, which makes perfect sense. There's a lot more going on. So what kind of innovations in air cooled systems are driving sustainability in these data centers?
[00:04:34] Speaker B: Yeah, another great question.
Data centers are becoming immense facilities and very powerful facilities. And with that they consume a lot of power.
So the single biggest piece on the cooling side that we can do to minimize or make a more sustainable minimizing a footprint is make the equipment more efficient.
Fortunately, the data center design is working hand in hand with the cooling manufacturers and we're elevating the requirement for leaving chilled water temperatures.
Looking at how this industry started, starts like any process cooling industry where they have to find commercially available products to meet that cooling demand.
In the case of air conditioning, you're traditionally running your chilled water out of the equipment at somewhere around 44 degrees Fahrenheit and that's very important to dehumidify.
As data centers have gone liquid to chip, it's allowed us to consistently increase our leaving chilled water to now we're regularly seeing designs at 70 or 80 degree leaving chilled water or even higher, and that allows the equipment to run significantly more efficiently.
So the biggest piece we're seeing there in sustainability is as leaving chilled water temps increase, were able to use significantly less power for the same amount of cooling and then also allowed with some purpose built equipment to develop economizers that wouldn't work for comfort cooling, but work very effectively in the data center world and allow us to even further reduce electrical consumption and or eliminate compressors from even running in many cases.
[00:06:22] Speaker A: So speaking of economizers, what are the types of air cooled economizers?
[00:06:28] Speaker B: Okay, absolutely. When you're looking at an air cooled chiller, the economizers probably fall into Three categories.
There's the legacy economizer, which would be same for the air conditioning industry, meaning you're bringing in 100% outside air. So the building system bypasses your entire refrigeration loop, just brings outside air into the building.
The concern with this is specifically for a data center is you bring a lot of the environment in when you bring in 100% outside air, and in many cases from a particulate matter or humidity concentration. Data centers don't want to bring in 100% outside air. So the industry has been pivoting away from that type of data, that type of economization for a number of years now.
The second option is how do I get my take advantage of my outside ambient air and get that energy or reject that heat all the way from my water loop to the outside air. So the second type would be a dry cooler, an integrated dry cooler, meaning we put a free cooling coil in parallel with our condenser fans, and the chiller system can bring water back from the building, run air across the coil, reject that heat direct to atmosphere.
If that system doesn't keep up because it is too warm outside, it's just based on a outside ambient condition.
The chiller, the traditional chiller circuit and the refrigeration circuit would turn on to trim that load and make sure you have the proper cooling to the data center.
The third is similar to the dry cooler, but we would use a pumped refrigerant.
The advantage there is when you use a dry cooler, you need to put some sort of freeze protection in the circuit so you're running glycol through your chiller loop.
When you go with pumped refrigerant, you can avoid that freeze protection in your refrigeration circuit. You can also avoid the additional static pressure required to pump your condenser air through two coils.
In a pumped refrigerant, you are basically running a variable speed compressor at a very low or a minimum speed to do that heat transfer from the ambient air down into your water loop via the refrigerant circuit that's already in that machine.
So all three are very viable for the data center industry. And all three kind of have their own place, depending on geographically where you put this data center.
[00:09:03] Speaker A: Well, putting this into practice, Jeffrey, how can an engineer determine which air cooled system is ideal for a particular project?
[00:09:13] Speaker B: So it's absolutely not one size fits all. Johnson Controls actively makes all three of these options, and it does depend geographically on where you're going. So my recommendation to a consulting engineer or to an owner.
Work with your equipment vendors.
All of us have the ability to give you full performance data maps of the of our pieces of equipment.
And then you, you align that data map with the bin weather data. So there's historical bin weather data which tells you how many hours a year your specific location is in each temperature bend.
What we have seen is on the pumped refrigerant economizers. They are absolutely a more efficient product in warmer climates.
And when you put that integrated free cooling or dry coolers, you're seeing efficiency gains in the northern colder climates.
So I would highly recommend anyone trying to do that evaluation, look at all the products, ask your respective vendors for their performance maps, and then put that into a bin weather data analysis and look at annualized power usage and you'll come up with a very clear picture of what makes the most sense for that specific location.
[00:10:32] Speaker A: And we've talked a little bit about data centers, but what application considerations impact air cooled system design?
[00:10:41] Speaker B: Absolutely. When you're air cooling a data center, the geographic location is very critical.
Primary concern would be the peak ambient temperatures. So most data centers are designing to n equals 20 data, which looks at the extremes over a 20 year period of time for location.
The warmer that temperature is, the more power and or more refrigeration equipment it will take to make the same same amount of cooling for your data center. So a data center in Phoenix would have different equipment than a data center in Chicago.
Phoenix gets to about 119, 120 degrees in the summer. Chicago, I think they're n equals 20 data somewhere around 100405 degrees.
So that is a piece of the geographic location. Another important factor of geographic location is altitude. The higher you are in altitude, the less efficient the heat transfer is. Each cubic foot of air that moves across the coil rejects a little bit of heat. So that will de rate the equipment a little bit with altitude. And then the third piece with air cooled equipment that sits outside on the opposite end of the scale is what is your winter extreme temperatures. And there are absolutely different considerations that need to be taken into account.
If you get down to freezing in the winter, or you get down 20 or 30 degrees below freezing in the winter, all of those have different implications with the type of equipment used and the manufacturer used. So that is one piece that is just your physical site location.
Second piece that's important about a consideration is the available real estate. So this is air cooled equipment that moves large volumes of air to ejected atmosphere.
The piece of equipment has a physical size and then it also has a physical basically barrier around it which needs to be maintained to prevent from recirculating air and making the equipment less efficient.
With the increased densities and liquid to chips, many sites start to run out of available real estate to put air cooled equipment in.
When we look at a megawatt of cooling, historically our box to cool, that was roughly 40 to 50ft long, about 8ft wide, about 8ft tall, and it needed about 20ft of width, times that length of area to set it. That was to cool a megawatt. Today with innovation and purpose built equipment, we're seeing those densities double on our, on our chiller equipment as well. So you get about 2 megawatts in that same space. But you do need to make sure you have enough roof space or chiller yard layout space to set the equipment.
And then the last consideration, that's really going into air cooled system design.
And it's something that's come up more recently in the last few years of data centers of sound.
You are talking about putting feasibly hundreds of these boxes which multiple fans each at a site.
So knowing your neighbors, knowing what your sound levels are at the property line is becoming important.
So that would dictate location of a site selection down to location of equipment on that site and and type of equipment all come into play when you're looking at that on air cool design.
[00:14:20] Speaker A: Yeah. Quite a lot of things to think about Jeffrey. And you really have quite a broad background. You've been in this industry for a while.
Tell me what was your first job? What did you learn from it or bring to this job?
[00:14:35] Speaker B: So yeah, everyone starts somewhere. So that's a good question. It goes back, goes back quite a while. But when I was 15 I got a job at a, at a local mom and pop pet store primarily they were the only ones that were hiring when you were younger than 16.
So that's where I started.
Couple key things learned. There is one, you know, if you find the right company and you have the right work ethic, they will definitely recognize that, take care of you and reward you for it.
So definitely saw plenty of growth in that position. Helped with college applications and moving into the career I'm currently in.
Another thing I learned is definitely respect juvenile animals. I remember one day we had gotten a brand new parrot in the store. I think it was probably 8 or 10 weeks old.
I went to pick it up and that bird bit right onto my finger and latched on.
Was refusing to let go to the point where I was extremely painful.
Very much felt as I lose my finger and the only thing I could think of is I dumped my entire hand and bird into an aquarium, which released the bird and I was able to get it back in its cage. And that was the last time I really wanted to handle that bird.
[00:15:52] Speaker A: Good advice for everyone. Yes, definitely.
And once again, this has been Jeffrey Jwers at Johnson Controls.
For more information on refrigerants, data center Sustainability or other H Vac topics, visit consulting specifying
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and don't forget to check in every other Tuesday for a new episode. Thanks for listening and catch you next time. Bye.
