UPS Rightsizing

There are many factors when selecting the right size UPS for your environment. If a UPS is too large for the application, you end up allocating more money and physical space upfront than necessary. UPS systems are more efficient the closer they operate to their rated capacity. But if a UPS is too small for the IT load, it won’t provide the required protection. It will shut down due to an overload and allow unconditioned utility power to the load and not provide battery backup. Plus, if a UPS is too small then it will not provide enough capacity for future growth.

Here are five key questions your Critical Power Solution Provider should be asking to ensure your UPS system is just the right size.

#1: UPS Capacity – How much IT load do you have today, and how much will you have 5 years from now?

To figure out the right size UPS for a new application, it’s important to know the power input for ALL equipment in the data center or critical environment. CEG would also need to know if the power input is based on operating power or nameplate power. (Operating power is smaller than nameplate power and is more indicative of the power consumed during operation.)

If you are replacing an existing UPS, the IT load may have changed since it was originally installed, and the current size may not be optimized for your current IT load. Many UPS systems have a display showing the load on the UPS in kVA or kW or showing the percent capacity the UPS is currently operating at.

If your existing UPS is operating at 20% of its capacity, then you may be able to replace it with a smaller UPS. On the other hand, if your UPS is operating at 80% to 90% capacity, then you likely need to replace it with a larger UPS.

It’s also important to consider your near future growth plans to avoid having to replace a UPS within a year because it is out of capacity. (Remember, the typical lifespan for a lead acid rack mount UPS is 5 years, so plan for the lifespan of the unit as well.)

#2: Battery Run Time – Based on the IT load, how much run time do you need with or without a generator to give time for a graceful shutdown of the IT equipment?

If you don’t have a generator, the battery run time needs to be long enough to perform a proper shutdown before the batteries run out. If you have one, the battery run time needs to be long enough to allow the generator to start and provide power. This usually takes a minute or two.

Next, consider how stable the grid is in your area. This can affect how many outages you have throughout the year as well as how long the typical outage can last.

Don’t forget, your UPS is not just there to provide backup power in case of an outage. It also cleans up the power from the grid to provide more stable power to your IT equipment. Click HERE to learn more about ways to clean up the power coming into your facility.

#3: UPS Technology – How critical is the equipment on the UPS to justify Off-line, Line Interactive and On-line Double Conversion?

Each type of UPS technology (Off-line, Line Interactive, and On-line Double Conversion) provides different levels of protection.

Off-line (Standby) UPS systems only monitor the incoming electrical feed to detect a loss of power and then switch to battery. These systems do not provide protection against “bad” power such as spikes and small sags.

Line Interactive UPS systems monitor the incoming electrical feed for loss of power and minimal high and low voltage conditions. In addition to battery operation for loss of power, it also provides minimal voltage regulation by use of an autotransformer.

On-Line Double Conversion UPS systems provide the highest level of protection by using an inverter and rectifier to continuously reconstruct the power output to always provide conditioned power to the IT equipment. On-Line UPS systems offer the widest available voltage regulation without going to battery, thus increasing the lifespan of the battery. Additionally, On-line UPS systems protect the IT equipment from loss of power as well as damaging power problems.

The UPS technology needed is based on the criticality of the operations supported by the IT equipment connected to the server. While individual workstations may only need an Off-line or Line-Interactive UPS, the more critical equipment operates best with an On-line Double Conversion UPS.

#4: Power Input/Output – Do you have existing electrical outlets you need to utilize? What kind of output (120 volt, 208 volt, single phase, three phase) do you need going to your IT load?

Input/output voltage influences the design of UPS systems. They need to align with your incoming electrical power to the server room as well as the power requirements of your IT equipment. For Edge environments, this is often either 120-volt or 208-volt.

Next, consider whether the UPS itself offers the correct voltage configuration to meet the input and output needs of the environment, or if your power distribution units or power strips can disperse the correct voltage to your IT equipment.

#5: Support – Do you have staff to implement deployment, disposal, and long-term support of the system? How are you going to monitor and access the equipment?

This question is geared more toward smaller or Edge environments. These facilities may not have the staff to handle the installation/removal or ongoing management of a UPS system. Make certain your solution partner can either assist or provide installation services for the Edge UPS as well as provide battery monitoring and battery changeouts.

#6 BONUS QUESTION – Does your electrical system have any points of failure that may negate all this redundancy?

Having a rightsized UPS is an incredibly important part of an emergency power plan. But rightsized redundancy alone may be providing you with a false sense of security if your electrical system is not designed to remove Single Points of Failure (SPOF). While a regular maintenance plan can help identify some issues (i.e., rodents, cracks, corrosion, obsolete parts at risk for failure), identifying SPOF is far from being a simple maintenance function. What’s required is a design-level assessment of your electrical system.

An audit of your current infrastructure will identify the points where there are no redundancies in place. An assessment also will ask and answer the “what if” questions about those potential pitfalls. What’s the process to restore power if failure occurs? What should be done to remedy the SPOF? What’s the business impact? These are all questions a good consulting engineer should answer as part of an assessment.

You can never be too redundant.

Whether you need a brand-new UPS, or you’d like to rightsize the system you have now, CEG can help. With a rightsized UPS from CEG, you’ll not only maximize money and energy savings today, but you’ll also have a system that is just right for tomorrow’s business needs.

You can also look to CEG for a SPOF assessment of your electrical system. Our evaluation will go a long way in ensuring your rightsized UPS works as expected and will truly give you the peace of mind that should come with having a backup power plan. CONTACT CEG today to get the conversation started!