High-performance thermal management systems represent some of the most expensive equipment in your data center. As a result, data center managers are committed to extending the useful life of this equipment. However, thermal systems are also responsible for a large proportion of data center’s energy spend. In a typical data center, cooling accounts for approximately 38% of total energy consumption. Legacy or aging cooling equipment with older technologies are typically much less energy efficient than newer models.
The Benefits of Retrofits to Thermal Management Systems
Cooling system upgrades or retrofits allows data center managers to take advantage of newer, energy efficient technologies without the need to replace entire units. Energy savings are often the impetus behind such projects, but they are just one of many advantages. When data center owners invest in thermal system upgrades, the results include:
- Significant and immediate energy savings that regularly generate enough cost savings for a full return on investment (ROI) in two to three years or less
- Incentives and rebates from local and regional energy providers that can offset initial projects costs by up to 50%
- Longer useful life of thermal management equipment, further reducing total cost of ownership (TCO)
- Increased reliability and decreased downtime through improved system performance
- Improved visibility into and control over environmental conditions in the data center
- Increased cooling capacity
- Reduced carbon footprint and greater operational sustainability due to lowered energy consumption
- Enhanced workforce productivity
What Types of Retrofits Are Available for Thermal Management Units?
There are many types of thermal management systems for data centers, such as chilled water (CW), pumped refrigerant, and direct expansion systems. Each type of system is made up of several critical components, including a compressor, CW actuator, coil, fan, sensors, and controls. Some components such as the compressors and coils, which tend to be the most expensive components within the system, can operate problem free for many years. However, fans, sensors, and control technologies are constantly advancing. If your thermal management equipment is more than a few years old, chances are there are upgrades available that could improve system performance. Indeed, an estimated 90% of data center cooling units installed in the last 15 years lack components that could save up to 80% of current energy consumption. Fortunately, retrofits or upgrades for these components are relatively noninvasive, quick, and cost effective to implement. Below, we explore each type of upgrade in more detail.
Fans are significant components of cooling system energy use. The internal supply fans built into most legacy thermal management systems are typically constant velocity centrifugal models. They operate at one speed, all the time, and they are usually programmed to operate at peak load. However, peak load conditions rarely exist in most applications, meaning the fans are often working much harder than they have to, overcooling the space and needlessly wasting energy.
Data center managers can fix this problem by switching to variable speed fan technologies, which save energy by enabling cooling systems to adjust fan speed automatically to respond to actual conditions in the room as they change. Instead of continually operating at peak load, the fans can automatically modulate up and down — from 25-100% depending on the system — to effectively match airflow output with load requirements in the room. This prevents overcooling and can reduce fan energy consumption by as much as 76%. Such large energy savings are possible because of the cube law, which defines the fan speed-to-power relationship. The law states that power is proportional to speed cubed. So even a small reduction in speed has the potential to significantly reduce energy use.
The two most effective fan improvement technologies available for retrofits are:
- Electronically commutated (EC) fans: EC fans are direct drive fans that are integrated into the cooling system by replacing the centrifugal fans and motor assemblies. They are best suited for downflow equipment. EC fans achieve speed control by varying the DC voltage delivered to the fan. They are inherently more efficient than traditional centrifugal fans because of their unique design, which uses a brushless EC motor in a backward curved motorized impeller. As a result, they still save energy when the cooling unit is at full load. While EC fans can cost up to 50% more than VSDs or VFDs, they generate greater energy savings and reduce overall maintenance costs, ultimately resulting in the lowest TCO. Additionally, EC fan technology feeds hundreds of data points about fan operation to the manufacturer or end user via an intelligent control or building management system (BMS), which can then be used to further optimize the environment.
Most thermal management systems come with a basic level of control that allows data center personnel to set and monitor temperature, humidity and airflow. Some controllers also provide information about component run times and alarm history. While the insight afforded by these controls is critical to monitoring the environment and ensuring uptime, adding more advanced, intelligent controls can further optimize cooling system performance and greatly contribute to enhanced energy efficiency.
For example, by replacing outdated system controllers with the latest Vertiv™ Liebertâ iCOM™ control platform, data center managers can integrate multiple cooling units into an intelligent system. Units work together as a team to cool the environment.
Overall, control upgrades lead to five primary benefits:
- Improved energy efficiency. Advanced controls can improve energy efficiency by as much as 10-20% for each individual cooling unit and up to 50% across the cooling system. This is accomplished by preventing unit fighting (where some units heat and humidify while others cool and dehumidify) and by ensuring coordinated fan speed for an even, consistent flow.
- Enhanced reliability. Improved, consistent airflow eliminates hot spots that could damage sensitive IT equipment. In addition, teamwork mode helps safeguard against problems with any individual unit. If one unit in a team stops cooling, the others can pick up the slack.
- Increased visibility. The right controls, coupled with the right sensors (see sensor upgrades below), provide a window into the data center environment and enable the thermal management system to be connected with the BMS. This gives data center managers complete visibility into environmental conditions across the data center, often from a single screen, making it easier to monitor conditions and spot any problems that need attention.
- Greater workforce productivity. In addition to streamlined visibility into data center conditions, advanced controls enable management of all units from a centralized location and often include capabilities for adaptive autotuning, allowing units to automatically respond to conditions in the room. This reduces legwork for staff, giving team members more time for other valued-added activities.
- Extended useful life of equipment. Teamwork mode reduces the wear and tear on individual units, prolonging the equipment’s time in service.
Advanced sensors often go hand-in-hand with new control systems. In many cases, thermal management systems rely only on a single return air sensor to determine the appropriate temperature for the supply air. This can result in overcooling or making the supply air colder than it needs to be because data center managers will want to factor in some margin for error — better to be too cold than not cold enough and risk damaging equipment. Replacing the return air sensor with up to six supply sensors positioned directly in the air stream and in the space that cools IT equipment provides exact temperature measurements that more precisely dictate the cooling capacity needed. Additional remote sensors can be strategically placed to sense air temperature and provide feedback to the fans. This allows the fans to respond with the correct amount of airflow. This decoupling of the capacity and airflow sensors provides a highly reliable and efficient operation, ultimately enabling the lowest possible cooling capacity and fan speed rate for adequate cooling and reliability.
To optimize fan, control, and senor upgrades, data centers should be configured to separate hot and air cold streams. A hot aisle/cold aisle configuration ensures data center infrastructure efficiency by keeping the hot air rejected from IT equipment separate from the cold air that cools the equipment. Thus, cooling systems don’t need to work as hard to manage the temperature of the supply air.
A physical aisle containment system or barrier that encloses the cold aisles supports this arrangement, further preventing cold and hot air mixing and boosting cooling system efficiency by 25-50%. This can extend the capacity of your cooling systems and enable additional IT density in each rack with no need to add more cooling equipment.
Thermal Upgrade Services
Vertiv infrastructure experts can help you determine the appropriate upgrades based on the age and capabilities of your existing thermal management equipment. As you consider your options, our teams can assist with:
- Calculating efficiency improvements and potential costs savings of each upgrade
- Identifying and applying for efficiency incentives and rebates that may be available from local and regional energy providers
- Determining ROI and length of time to project payback
Once you decide to go forward with upgrades, factory-trained Vertiv technicians can professionally install your new fans, control platform, sensors, and/or aisle containment system with little or no disruption to data center operations, positioning you to immediately take advantage of the cost savings and peace of mind generated by higher-performing, more efficient thermal management systems.
Go online to learn more about thermal equipment upgrades or read our recent healthcare case study for an example of a Vertiv thermal upgrade project that resulted in $360,000 in annual energy savings, earned nearly $700,000 in rebates, and fully paid for itself in less than three years.