Flexible friend | Archive Titles

Table 1: ups cost of ownership comparison
User’s actual load 180 kVA. Electricity cost (typical commercial premises) 5.7p/kWh
Online, double-conversion ups	PowerWAVE transformerless solution	Transformer-based solution
Number of ups modules in parallel	3	2
ups module rating (kVA)	100	200
Percentage load	60%	45%
Efficiency	96%	91%
Input power factor	0·95	0·77
User’s load (kW@0·8pf)	144	144
Total ups input (kW)	150	158·24
Total input current/phase (A)	227·9	296·6
Total ups heat loss (kW)	6·0	14·24
Total ups running cost/year	£2996	£7111
Is the ups in an air conditioned room?	yes	yes
Additional air conditioning running costs/year	£1198	£2844
Total ups running cost/year	£4194	£9956
Cost of ownership saving for a period of five years	£28 810