Uninterruptible Power Supply (UPS) systems are essential for maintaining the power stability of data centers. They provide a reliable backup battery power source during a short outage, ensuring that critical systems remain operational. UPS systems play a vital role in safeguarding data integrity and overall system performance by preventing downtime and protecting sensitive equipment from power surges and fluctuations. Implementing a robust UPS system can enhance the resilience of your data center, ultimately contributing to better service delivery and operational continuity.
Double Conversion UPS Systems
A Double Conversion Uninterruptible Power Supply (UPS) system uses a rectifier to convert house power to direct current (DC). This process charges the batteries while simultaneously converting the power to alternating current (AC) through an inverter. Although it is one of the most reliable systems available, the double conversion process has historically made it less efficient.
In the past, a UPS could achieve around 92% efficiency, considered adequate at the time. However, if the load dropped to 20%, the efficiency could fall below 50%. Over the years, advancements have improved these systems, and now they can reach efficiencies of up to 98% or 99%, even at a 10% load.
Power efficiency, as well as reliability, is significant for mission-critical applications. For example, servers typically have redundant power supplies; only one is needed to operate, but having two ensures backup reliability. Customers often use two UPS systems—large or small—for critical systems like servers and network core switches. Each power supply is connected to a separate UPS. If one UPS fails, the other UPS assumes the load. This is defined as a ‘dual bus’ topology.
When planning two UPS systems for a ‘dual bus,’ remember not to exceed a maximum of 50% load on either system. This is the most common error we see for our mission-critical clients when setting up and maintaining a ‘dual bus’ system.
Batteries in UPS systems
Batteries – long-lasting batteries should be used in a UPS system. Different types of batteries – the most common is a valve-regulated lead battery (VRLA) (which is like a car battery). There are also Tiny Gel Cell batteries, which are becoming obsolete, and the traditional Wet Cell Batteries for large applications. Most VRLA batteries have a 3–5-year life cycle and should be replaced the year before expiration. For example, a five-year battery should be budgeted for replacement starting at four years. This is the most common problem that many customers see.
Lithium-ion batteries, or similar batteries like Lithium, are becoming the more popular option because of their smaller size and lighter weight, and they last over ten years instead of the typical five-year VRLA batteries. When they do fail, they don’t break the chain. However, specific issues need to be addressed when Lithium batteries are deployed.
Scalable/Modular UPS systems
Many customers opt for dual bus configurations for UPS systems when critical reliability is needed. Several years ago, scalable or modular UPS systems were introduced. These systems have a large chassis into which additional modules can be plugged in. For example, if you have a 20-kW load and a 100-kW chassis, you can start with one 20-kW module and add more as your demand grows.
One reason for choosing these systems is that they can address utility power ‘inefficiencies’ by adding as you grow. However, the downside is that scalable systems are initially more expensive than traditional options. Advanced Facilities (AFI) generally does not recommend scalable UPS systems, as they believe using a single, full-capacity system is more cost-effective in capital expense ($/KW) and still provides high energy efficiency with today’s technology.
We have extensive experience in handling issues with power quality and outages.
Our capability to design modular/scalable UPS systems that can be expanded efficiently to accommodate customers’ growing needs. Suppose your battery fails or there’s a significant power outage that your UPS system cannot manage. In that case, AFI can assist in specifying the right backup system for your data center or specific application. They provide free consultations to help choose smaller systems and the appropriate components for an IT closet or a large data center.
“We assist by asking the tough questions, such as where you envision your equipment three years from now,” says Tim Amann from AFI. If that question remains unanswered, they can arrange visits to larger data centers, enabling you to observe their operations, speak with customers, and gather valuable insights.
If you need help finding the right UPS systems, contact AFI [email protected], call 513-942-9900, or message us through our Contact Us page.