The design of modular UPS systems allows more efficient ac - ac operation than that available from a traditional standalone parallel redundant UPS. This arises because the efficiency of all UPS systems drops as their output load decreases.
With standalone systems, redundancy is typically achieved by using two UPS connected in parallel. This 1+1 arrangement means that each UPS can never be run at more than 50% of full load. By contrast, in an N+1 modular system where N is greater than 1, each module is more fully loaded - and the higher the value of N, the higher the loading on each module.
Improved ac efficiency significantly reduces electrical power consumption costs. It also reduces cooling costs by reducing waste heat generation.
Example 1: Increase of modular load as N increases
1+1 configuration: Maximum individual UPS load = 1/(1+1) = 50%
4+1 configuration: Maximum modular load = 4/(4+1) = 80%
Example 2: Obtainable benefits and cost savings from increased N
The significant reductions in heat losses, CO2 emissions and electricity running costs available by using a multiple N+1 modular UPS instead of a free standing 1+1 configuration are shown below: |
