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Uninterruptible Power Supply - 7 Points to Smart Cost Effective UPS Selection

Generally, when buying an Uninterruptible Power Supply (UPS), we look for the lowest price of a simplest unit that meets requirements. Generous rewards await however, those that look around, and consider, smart cost effective solutions before buying a UPS.  

UPS systems protect computers when utility power is available and continue to supply conditioned power from batteries at power outage. According to the specific application, basic requirements should be defined, such as the type of the UPS, its Capacity (Size) in VA (Volt-Ampere) or kVA (kilo-VA) units, and the battery backup time.

After you know the basic requirements you can start shopping for the best price of a suitable UPS. You can however make better. By surveying the market, looking around, checking what is available at what prices, and considering the creative recommended guiding points, you can make dramatic cost saving, generally reaping additional performance benefits.

 Information about specifying the basic requirements as well as market survey results both can be found by visiting a single website. UPSonNet, is a source of information about Power protection and UPS systems, publishing UPS selection guides, as well as   a unique service providing Industry average UPS Price list of systems from 350VA to 120kVA.

Here are seven points to consider for making a smart cost effective decision when buying a Power UPS.    

1. As a rule:  For better protection, Line Interactive type should be preferred over Standby type and On Line type over Line Interactive type. Therefore, unless other considerations prevail, choose the better system if its price is only slightly higher.

2. Compare specified UPS price to the price of next size system. Consider buying bigger unit, if the added price isn't significant. Bigger UPS enables to increase future loads, it has bigger battery with increased backup time, and extends battery life time.

3. Consider buying a bigger system if you need to increase battery capacity, beyond the standard battery coming with the UPS. You might pay for a bigger UPS, already equipped with the battery size you need, considerably less than the cost of the smaller system with extended battery.

4. Check the cost effect of splitting the load or buying systems which can operate in parallel. In some cases the cost of two systems, each rated half total capacity, may be lower than a single UPS system.

5. Consider using several stand alone single phase UPS systems, instead of a three phase UPS, provided loads and installation allow. Generally, the cost of two or three single phase units is less than one three phase system. Multiple systems may in certain cases increase power reliability by adding redundancy.

6. Consider the cost of using three single phase UPS systems, each fed from different phase, instead of a single three phase UPS systems, provided loads and installation allow. This configuration allows continuing partial operation, in case of a single UPS or input phase failure.

7. In redundant configuration, two or more units work in parallel, while at least one is a spare unit. Thus full power is supplied even if a single UPS fails.
Check possible combinations to find the lowest cost. For instance, for a redundant system supplying 20kVA load, compare the cost of two parallel 20kVA systems, to a single three parallel systems 10kVA each. (Common mistake assumes that the last solution is always cheaper, due to lower total power).

 How much can be gained?

 Using UPSonNet average UPS Prices, you can conceive scenarios in order to asses the possible gains or savings that can be achieved by implementing the said points.

 Here are some examples; based on average UPSonNet May 2009 UPS Prices: 

At low power levels, the price of an Online UPS is almost twice compared to Line Interactive type. This ratio decreases when power grows. You will have to add only 10% to buy a 5kVA online system.  

 You need to add only 20% to increase an Online UPS from 1kVA system to 1.5kVA or from 20kVA three-phase UPS to a 30 kVA unit.

 Three 5kVA single phase UPS systems each per phase will cost 55% ($ 3530) less, compared to a single three-phase 15kVA UPS.

Three 30kVA units in parallel redundant configuration for a 60kVA load, save 25% ($15,050) compared to two 60kVA units.

 Implementing the suggested cost effective points, before buying an Uninterruptible Power Supply, using average UPS Prices, may lead to a better solution with dramatically lower cost. The price list and the said steps should however, be used for guiding purpose only. Local availability and price of the specific system, as well as additional technical restraints on using the suggested solutions, should all be professionally checked before a final decision is made.

About the Author

Meir Portnoy is VP of UPSonNet -Information Source operating since 2006 from USA ( now also from Israel), providing information about Power Protection and Power UPS field. UPSonNet website includes also Selection guides, UPS Industry Prices, most extensive UPS-Glossary latest UPS News, updating about important industry products, developments and trends. For more information visit: www.upsonnet.com.

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