Case study CIBSE award winner
> • Ascertain the effectiveness of current maintenance
regimes; and
Figure 1: Assets inspected
• Identify no-cost/low-cost initiatives and capital • Eleven air-handling units
investment opportunities. • Two main water chillers
One of the barriers we often face is the lack of • Sample of terminal units
information about what equipment and systems are • Building management system
being used on a site. Only rarely are we able to find • Two direct expansion split air conditioning units
a log book – we found just one in the course of 300
inspections, for example. However, with Eland House
we did discover the necessary information on systems, Once these quick-wins have been established, capital
and inspected a range of assets (see Figure 1). investment opportunities can be identified for further
We identified a range of low-cost energy saving analysis of energy saving measures and paybacks on
initiatives. We found that, if implemented, these these. Such measures include, for example, equipment
quick-wins could yield a 9.9 per cent reduction of that can analyse data and performance of large chiller
plant; sub-metering; looking at replacing belt-driven
fans with direct drive ones with variable speed; and
Once the quick-wins have been
so on.
established, capital investment
Around these capital investments, which tend to
have a payback period of two to three years, there are
opportunities can be identified for also more peripheral issues to consider, such as solar
further payback measures
shading and lighting, which of course impact on the
cooling load and plant energy costs.
the building’s energy load – which equates to an To look at cooling load in relation to plant size,
annual cost saving of £32,642 and a CO2 reduction we used the CIBSE guide, TM44, to help with the
of 238 tonnes (see Figure 2). These modifications are assessment of cooling load, basing this on occupancy
to do with things we find in most buildings, which density and solar shading levels compared with the
include: combined cooling capacity of the equipment installed.
• Building management system (BMS) set points not With Eland House, the cooling load equated to 2,585
correctly set; kW, while the combined cooling capacity equated to
• Heating fighting cooling; 2,614 kW of installed plant – which was the appropriate
• Humidity levels not correctly set up; level.
• Refrigerant levels within chillers; As a result of the changes made at Eland House –
• Lagging missing from ductwork and pipework; and resulting in the 9.9 per cent reduction in total building
• Dampers control valves not connected properly. energy load – the Display Energy Certificate rating >
Figure 2: Air-con inspection: low-cost energy saving initiatives identified
Description of works – for more detail, see Figure 3 Energy Carbon dioxide Annual cost Implementation Payback
reduction reduction saving cost period
kWh Tonnes (Months)
BMS control adjustment, calibration and policy adoption 277,296 105 £12,474.00 £2,000.00 2
Filter replacements 47,500 26 £3,970.00 £1,850.00 6
Chilled Beam BMS Control modifications 15,000 8 £1,254.00 £600.00 6
AHU 1 - Repair / Replace CW valve 12,500 5 £800.00 £400.00 6
AHU 1 - BMS control adjustments 10,000 4 £650.00 £300.00 6
AHU 2 - Repair / replace control valves 45,000 14 £2,034.00 £500.00 3
AHU 2 - Re-fit control actuator 30,000 9 £1,350.00 £350.00 3
AHU 3 - Repair / replace control valves 12,500 5 £800.00 £400.00 6
AHU 3 - Replacing ductwork lagging 6,000 2 £300.00 £300.00 12
AHU 4 - BMS control adjustments to reduce Air Flow 70,000 38 £5,800.00 £300.00 1
AHU 6 - Repair / replace control valves 2,250 1 £145.00 £175.00 15
AHU 6 - Repairing the damper control 5,835 1.4 £196.00 £175.00 12
AHU 101 - Repair / replace control valves 45,000 14 £2,034.00 £500.00 3
AHU 104 - Repair / replace control valves 8,550 4 £550.00 £175.00 4
AHU 104 - Repair the damper control 2,950 2 £285.00 £175.00 8
549,881 238 32,642 £8,200.00 3
32 CIBSE Journal February 2010
www.cibsejournal.com
CIBSEfeb10 pp30-32,34 eland.indd 32 29/1/10 14:30:30
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76