When It Comes to Determining the Environmental Footprint of a UPS System, Factor in the Battery

Today’s industrial, scientific research and production laboratories all have a common goal—to maintain a high rate of throughput, which can be measured in a number of ways. Most of these labs are highly automated, and in many cases standard systems, instruments and procedures are codified to meet stringent guidelines mandated by the industry and internal to the organization. This common goal drives investing in the new instruments, automated laboratory systems and techniques that lab managers are constantly seeking.

Labs that make a product or test samples run a constant cycle of lab instrument upgrades in order to maintain a high level of productivity and throughput. The logic driving the decision to update a mass spectrometer, for example, is typically based on an exponential increase in the number of tests that can be performed by the up-to-date instrument. In addition to keeping throughput at peak levels, today’s lab manager is also faced with the challenge of leaving a smaller carbon footprint in terms of the resources a lab uses. The resources that probably come to mind are costly reagents and other essential materials required to perform these tests.

When we look at this “greener lab,” we can look at a number of layers. In the 1980s those developing computer networks adopted the Open System Interconnection Reference Model (OSI model) to ensure that all hardware, software and internetworking elements shared common communications, hardware and other protocols so that everything could connect and operate as a single system. If, for example, we use this model to look at a lab and all the elements that give a mass spectrometer the materials it needs to perform its tests, AC power quality and reliability will be at the bottom layer of the resources being acquired.

Many laboratories use a smaller UPS system at each instrument—a line-interactive, or “switching,” Smart- UPS for equipment using less than 3kVA or 2100W, mostly due to a lower cost. This approach has several advantages and a few drawbacks in terms of leaving a smaller carbon footprint.

In the June 2009 issue of Lab Manager Magazine, author Michael Stout discussed the impact of power problems affecting the precise operation of labs by focusing on a common issue that most lab managers face when they deploy one of these smaller, computer-grade line-interactive UPS, to combat the effects of the dirty, unregulated AC power found in most laboratories.

The device more suited for laboratory equipment, from the perspective of output power regulation and power backup time required, is clearly one that regulates AC power continuously— an online UPS. This better UPS will transfer seamlessly without switchover time and deliver the same clean sine-wave power to the instrument when the power drops out.

In addition, in endeavoring to create a greener laboratory, the primary impact any UPS has on the environment in terms of maintenance is the battery replacement cycle. The line-interactive, Smart-UPS carbon footprint is significantly higher due to its very design.

Battery overview

At the heart of every UPS you will find a battery, and due to the large number of smaller UPS units typically used in laboratories of all stripes and sizes, the cost of ownership may be much higher when this element is factored into the equation. Typically the referenced UPS topologies use valve-regulated sealed lead-acid (VRLA) batteries, as they provide the highest power density at the lowest cost. Until recent developments in technology, the five-year-rated VRLA battery used in a UPS typically had a four- to five-year service life if maintained in a 77°F (25°C) environment and properly charged.

Five-Year–Rated Batteries

Twelve-Year–Rated Batteries

In addition to not maintaining the battery at the proper charge, the VRLA battery’s service life can be shortened further by high temperatures and too-frequent discharge and recharge cycles. Line-interactive UPS models can switch to battery mode too often if installed where utility voltage regulation is poor. This is not the case with double conversion online UPS models, as they draw power from the battery only when the utility voltage is extremely low or lost completely. As the online UPS typically costs more to make, the battery chargers often are better designed and better at maintaining the battery’s charge, resulting in a longer service life.

Though the VRLA battery’s design has changed little in the last several years, a new VRLA battery is rated to last up to 12 years. Similar to a standard five-year-rated VRLA battery, these batteries will last their rated life when operated at room temperature and used in “standby service” mode, as described in the previous paragraph. In simple terms, these new batteries have a higher lead content, as well as a larger internal surface area. The result is slower overall degradation of the chemicals and internal components.

The charts outline the effect of higher temperatures on battery life. Though most labs are temperature-controlled, these charts show how drastically battery life is reduced at higher operating temperatures.

Lab managers who install a line-interactive Smart- UPS enjoy an overall lower cost up front. However, the total cost of ownership shows a very different picture. The typical life of a standard battery in a line-interactive device is two to two and a half years, so over a 10- year period the user will experience three to four battery replacement cycles. This ends up costing the lab user more because of the need to buy and replace batteries. Also, this cost increases exponentially as the size of the UPS increases, since larger models use more batteries. Another factor that will drive this cost higher is a runtime of 20 or 30 minutes that draws on reserve battery power, which typically requires a UPS with an additional external battery pack.

When UPS maintenance is viewed from the perspective of overall impact on the environment, the resources required to recycle batteries are significant, both from a recycling viewpoint as well as the number of times a battery needs to be changed out. From the time replacement batteries are ordered, the energy required to deliver new and return old, heavy lead-acid batteries has an impact on the environment. Recycling requires the battery manufacturer to use resources when taking old batteries, recharging their chemicals, reconditioning metal and making other efforts to repackage batteries. The impact on resources such as water and energy must be taken into consideration.

A UPS that leaves a smaller footprint

Recent snowstorms and corresponding power outages may have caught your lab without an adequate power protection “parachute” in place. In many cases lab managers who use the ubiquitous line-interactive Smart-UPS device find that it costs a lot to maintain. Many lab users give up on maintaining the device, but this is not recommended, as the batteries can swell and even leak gas if not replaced. However, an online UPS that uses internal batteries if—and only if—there is a power outage gives users a much longer battery replacement cycle. A new 12-year-rated battery will have a much smaller carbon footprint but, equally important, it will be ready to supply clean power when your instrument and other automated test equipment are exposed to utility power.