ENERGY EFFICIENCY BUILDING CASE STUDY
Swimming pool – new trend control Swimming pool – chemical cover
Staircase lighting control – SC 1, 2, 3, 4, 5, 6 Plant room lighting control
Meeting room lighting control - YB121A,B,C Sports hall lighting control
Garage lighting control Paper towel change over Totals
Initial cost Installation £3,600.00 £1,485.90
£5,280.00 £3,960.00
kWh
Annual electricity savings Cost saving CO2
(tonnes)
Annual gas savings kWh CO2
33,200
105,500 23,880 11,248
£6,120
£1,406.52 £662.50
£4,024.00 125
12.42 5.85
35.53
(tonnes) 6
9,240 Figure 1: Energy efficiency improvement measure in 2010, with estimated savings
at cutting waste and improving efficiency in the tower and the three wings (see Figure 1). The changes included improvements to lighting systems and ongoing reviews of heating and plant operations. The payback periods for these measures
varies widely. The most expensive measure, at £5,280, is the plant room lighting control – with a payback period of 2.5 years. Installing a PIR lighting system in the meeting rooms will cost £3,960 and take four years to pay for itself. However, most of the measures centre on relatively low-cost reviews of the effiency of heating and plant operations. The estimated annual savings from the
eight measures total nearly 140,628 kWh of electricity and 33,200 kWh of gas – providing estimated cost savings of £12,200 a year. The overall cut in carbon emissions is calculated at 111 tonnes of CO2 per year.
Measure Electricity
savings estimate (kWh/yr)
Implemented measures Project list 2010
Sub total Shorter term payback measures:
Staff engagement initiative Building management system scheduling and control review
Sub total Medium term payback measures
Replace T8 with T5 in wing offices Reduce the PIR delay time in open plan offices, meeting rooms and circulation areas
Sub total Total
200,000 18,300
218,300 1,098,928 0 973,200
107 10
117 770 Figure 2: Recommended further initiatives with timescales, projected payback periods and expected savings to be made
18,000 1,600
19,600 128,100
65,000 6,000
71,000 118,240
3.6 3.8
3.6 0.9
296,000 444,000
740,000
376,00 564,00
940,000
229 343
571
37,990 56,900
94,800
3,000 35,000
38,000
0.1 0.6
0.4
Gas savings estimate (kWh/yr)
Carbon dioxide saving
(te CO2 /yr)
Staircases The refurbishment also included work on the staircases. Measurements indicated that lighting levels in the staircases of the wings and tower areas were within recommended values of 300 to 400 lux. Although the lighting equipment is reasonably efficient, there is potential to change the installation by removal of fittings to achieve further energy consumption savings. Lighting consumption in the staircases is estimated to be 232,000 kWh of electricity annually. With lighting fitting densities reduced by 50% in the staircases areas while still maintaining normal illumination standards of 300-400 lux, there would be a saving of 105,500 kWh a year. The assessed cost savings are £6,120 pa.
Further action Power Efficiency recommended a range of further energy saving measures that
Cost saving (£/yr)
Guide price (£)
Simple payback perid (yrs)
140,628
12,213
179
33,200
140,628 140,628
33,200 33,200
82 82
13,700 13,700
9,240 9,240
0.7 0.7
34
CIBSE Journal May 2011
www.cibsejournal.com
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