Hello!
I’m glad you’re back, or welcome if it’s your first time here.
I have already begun to discuss the carbon life cycle and the Energy Pyramid, which are two of the basic ideas for where a building’s carbon emissions come from and how to reduce it’s environmental impact. If you’re new, check out some of my other articles to get you started with the basics:
Energy Pyramid: Introduction & Conservation
Energy Pyramid: Energy Efficiency
With this article, I want to do something a little different. I want to focus on one building type and talk through the specifics of what some improvements may be for this application by following the Energy Pyramid. This is also a bit of a test, I’d like to see if you find this useful to see if I should expand on this type of content, so let me know in the comments what you think! Please, don’t hold back, lay it on me!
Why Data Centers? Well, I am giving a talk this week about Data Centers! I realize this may not be for everyone; however, everyone who uses the internet is affected by Data Centers. Data Centers are growing at a huge rate. According to a Bloomberg article from March 2021, data centers are expected to double by 2025. Which is why I am looking to help data center owners reduce their carbon footprint. Even if your building isn’t a data center, maybe it could still spark some ideas.
So, let’s get started!
Discovery Questions - "The ability to ask questions is the greatest resources to learning the truth." - Carl Jung
When first taking on any project, it’s important to start with prioritizing wants, and needs. Are there maintenance or comfort issues? Is the focus on energy bill reduction or are there specific sustainability goals? Is this project even desired or is it part of some other requirement? Is there a budget or will financial assistance be required?
These are just some of the discovery questions asked. The answers are different for every project no matter the industry so it’s important to always have this discussion between the data center owner and the project developer. It helps the person developing the project to prioritize solutions and come up with a construction and financial plan best suited for the customer.
For data centers, the number one priority is 24/7 operation. As an Energy Engineer, I don’t have much impact over controlling the facilities but this is still something that affects the project. The biggest challenge with maintaining 24/7 operation will be during construction with scheduling and backup power. Not to say it isn’t impossible, just that special care must be taken during that time.
After determining the customer’s priorities, the audit takes place.
Let’s begin to use the Energy Pyramid to help guide us through the building.
Conservation
I like to view this first step as “Saving what you already have.” Just like saving your money in a piggy bank, except your money is energy and your piggy bank is your building. So where is energy lost? That is the main question that is asked during the first phase.
The first main contributor of energy loss are your walls, roof, fenestration, entrances, and sometimes floors by heat transfer. Increased insulation and decreased infiltration help maintain the desired space temperature so the system is not conditioning outside air or heat.
The ideal data center only contains computers, servers, and other related equipment, therefore occupancy comfort is crossed off the list. This makes this first step somewhat simpler. Minimal windows, skylights, and entrances would also be key in reducing unwanted heat transfer. Servers don’t care about getting enough natural light for their mental well being like people do. Maybe one day solar powered AI robots will care, but that’s a later problem.
Similarly, for ducts and pipes, elimination of leaks and increased insulation also assists in energy conservation.
The biggest challenge for data centers is keeping the equipment cool. If the HVAC stops working, the room gets hot very quickly. This heat generated by the servers, can it be used elsewhere? Is there an adjacent space that can use that heat? Maybe heating an occupied space. If the occupied space needs cooling, is there a possibility that an absorption chiller can be installed? An absorption chiller uses heat to cool a space. That sounds confusing initially, but here’s a great video if you’d like to learn about how it works.
Energy Efficiency
The next step in the Energy Pyramid is Energy Efficiency. Now that you have conserved the energy you have been using, you want to make sure you get the most out of your energy. I like to think of this transition as going from your change jar or mattress money to opening up an account at a bank. By having your money at a bank, you can more efficiently transfer funds, open up credit or debit cards, gain small interest, set up allocated accounts, and pay bills online, which all save you time and therefore money. By using your energy more efficiently through maintenance or upgrades, you gain similar flexibility. Let’s go through a few examples:
First, the easiest, cheapest, while still being impactful upgrade you can do is switch lighting to LEDs. This is an absolute no brainer. Next time you have to replace a bulb, buy an LED. LEDs give off less heat, are just as bright, brighter, or can even change colors, and use significantly less energy. Take a look at this video to witness how much less energy it uses. You may still have fluorescent or CFL lighting in your data center which do use less energy than incandescent; however, still LEDs will have an impact.
The biggest energy monster is of course HVAC. I go into a bit more detail about HVAC options in my previous article, Energy Efficiency, about the three main options you have when considering HVAC efficiency.
Something that a lot of people don’t think of when it comes to energy efficiency are transformers that step down the utility power lines to the facility. After their Effective Useful Life (EUL), efficiency drops significantly. Simply replacing transformers, like for like, you can see a great payback for the investment.
In data centers, there are two main types of energy efficiency options that are unique to their use:
- Cooling: whether it is an air cooled room or liquid cooled racks.
- If there exists an air cooling process, then making sure the air flow temperature, pressure, and direction within the rack aisles are optimized.
- If there are liquid cooling racks, then checking for leaks, temperature differences, and flow rate are important.
- Computing Power: efficiency in processors in CPUs, GPUs, or memory. An Energy Engineer won’t get into the specifics of the data center equipment, that is a bit out of our realm; however, like any piece of equipment, it has an EUL. Consider asking if it is time to upgrade your computer and servers.
Demand Management
Alright, we have saved our energy usage and made it as efficient as we can, what’s next? Demand Management. Just like as the title suggests, this step consists of managing the load demand of the system. To do this properly, certain building controls are required, HVAC controls, lighting controls, Building Automation Controls, and an Energy Management System. For a data center, this may also include load management of the servers.
In our money comparison, I like to think of this step as your budgeting and accounting of your energy. This requires, allocating bank accounts for different things like bills, savings, and checking accounts, setting up automated bill payments, and planning for future expenses. Having a proper system in place to manage your equipment and therefore your load allows a lot more visibility into where the energy is going and how to improve or transfer it if you need to.
If a large load is forecasted for the data center, then the HVAC equipment can prepare by pre-cooling the space before the servers generate the increased amount of heat. This allows for a slow ramp up of the HVAC system. Alternatively, if there is a sudden increase in heat generation in the space and the HVAC equipment has to react, as opposed to prepare, by ramping up rapidly, then a larger demand of power is required of the HVAC system. Though the same amount of energy may be consumed, higher instantaneous power demand still results in a higher bill charge.
Another type of demand management would be load sharing. Depending on the type of data center, it may be more beneficial to share computing load between multiple servers as opposed to fully loading one. This is the same for most equipment, including chillers. Managing cooling load between multiple chillers may be beneficial if one chiller is running at full capacity a majority of the time.
Renewable Energy
Lastly, renewable energy! Now that you have saved your energy, made it as efficient as possible, and are managing it with the most up to date controls system, we can install an optimized renewable energy system. (please note: that there are always exceptions to the rule and we are discussing an ideal scenario.)
I am giving you a bit of a spoiler to whats to come to the next Energy Pyramid blogs but that’s okay.
The reason renewable energy systems are saved for last is because at this point in the project several things have happened:
- Less energy is being used
- How the building is run is more closely maintained and understood
- The building consumption is optimized to the equipments requirements
These three advancements ultimately result in a smaller renewable energy system that will also be optimized for the use of the building, saving you money in the system purchase and running your building.
That's it!
Well, almost. What happens next is the Energy Engineer or Project Developer collects the customers wants, needs, and what was found through the audit. Energy savings are calculated based on the current building consumption profile and what solutions are proposed. Dollar savings are estimated based on current and possibly future utility rates. Typically, several solutions are presented based on needs and financial allowance leading to a discussion or two before determining the final plan for improvements.
Projects can be done all at once, or even broken up into phases.
What's next?
Once construction is completed, a commissioning agent will verify installation and measurements can be set to see how much energy the building is saving. These measurements can be used to verify proposed savings or recorded for reporting purposes like in an ESG (Environmental, Social, Governance) report. And of course, general make you feel good about what you accomplished, give yourself a pat on the back!
Let me know in the comments, did I forget anything? Did this spark any ideas for you? What projects are you considering for your data center or building?