continuous optimisation

Continuous Optimisation

JISC Improved Sustainability Across Estates

Through The Use of ICT

Continuous Optimisation – an Imperial College estatesinitiative reducing the carbon consumption of plant & services, and how

ICT infrastructure underpins it’s delivery

Continuous Optimisation - Content

Content

• Continuous Optimisation (ConCom) – what is it?– Background– Initiatives

» Flowers building ‘night set-back’» Air change rationalisation» Filter optimisation

• How does ICT support Continuous Optimisation?– TREND system– Carbon Desktop– Real Time Logging


Continuous Optimisation (ConCom) – what is it?

Continuous Optimisation - Background

Background

• Imperial College’s ‘Carbon Management Plan’ requires us to achieve a 20% reduction in carbon consumption by 2014.

• 84,026 tCO2 reduced by 16,805tCO2 to 67,221tCO2

• Continuous Optimisation of plant & services, targeted to deliver 4,903tCO2

• This can only be achieved if we have:» Extensive control systems» Robust operational information» The cooperation of the academic community

• As a Science, Engineering and Medicine focussed University, our research and teaching relies heavily on controlled environments.

Continuous Optimisation - background

• We are challenging how environments were originally commissioned by considering:

– The original design, at sign-off– How the environments are now being used– The occupation strategy– What service strategies are really needed to provide, safe and

productive environments, without compromising our research & teaching.

• Through Continuous Optimisation (continuous commissioning ‘ConCom’), we are implementing:

– Air change volume adjustments– AHU operational set-backs (temperature & time)– Introducing more efficient plant– Adjusting pump delivery to meet flow demands– Improving filter efficiencies– Introducing occupancy controls e.g. CO2 sensors, ‘user switches’

Continuous Optimisation – Flowers building ‘night set-back’

Flowers Building ‘Night set-back’Initiative


Flowers Building ‘Night set-back’Methodology

• We identified Flowers building main air handling services were operating 24 hours a day, 7 days a week

• Environmental conditions and operational dependencies were discussed with users

• The four supply & extract air handling units were re-commissioned to ensure they could continue to operate to the original design

• This helped establish that new motorised dampers and controls would be required to manipulate the air pressures and volumes, while ensuring that dedicated equipment areas continued to receive 24hr ventilation / cooling.


Methodology (cont’d)

• The energy profile for the building was then measured across a normal week

• The new controls and motorised dampers were installed

• The air supply pressure was then reduced from 400pa to 300pa

• The air volume delivered overnight was reduced to an average of 6 air changes / hour, from 13, between 22.00hrs to 07.00hrs.

• The energy profile for the building was measured throughout this process and checked in subsequent weeks.

• Further commissioning followed; reducing air pressures, and extending the time to between 18.00hrs to 07.00hrs, more savings resulted.


Savings

• The base load has reduced from 280kW to 210 kW a 70kW saving• Day time air pressure was reduced, heating & cooling savings resulted• This realised overall savings of

Savings kWh £ CO2 TonnesNight Set Back 273,000 23,342 145.8

Reduce daytime pressure 218,400 18,673 116.6

Heating & Cooling 70,175 6,000 37.5

Add weekends 28,080 2,401 15.0

Total 589,655 44,416 315


Electricity profile the week before the damper replacement and night setback initiation

Dampers replaced (Mon 5th & Tues 6th October)

Night set back initiated Wednesday 7th October

kW

400

320

240

160

80

Base load has reduced from 280kW to 210kW

Continuous Optimisation – Air change rationalisation

Air Change Rationalisation


Air Change Rationalisation

• As part of our ConCom programme we challenge the air change strategy for each building, comparing the design, current operation and recommended standards.

• CIBSE guidelines recommend 6 air changes / hr for laboratories.

• We find that our environments are commissioned within significant excesses of this standard, often between 10 and 14 air changes / hr.

• Working closely with users, we measure the current air changes, and then gradually adjust the fan-sets, optimising their delivery but without compromising the business need or safety.


• This approach can deliver significant savings through: – reduced fan motor speeds– reduced heating demands– reduced cooling demands

• An example of this approach in the Sir Alexander Fleming building, where we focussed on 3 of the main AHU’s has already delivered annual savings:

980,588 kWhrs, £31,450 275 tonnesCO2


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Floor area served m2 Volume served m3/sFloor AHU 1 AHU 2 AHU 3 AHU 1 AHU 2 AHU 3

2 196.35 196.35 392.7 540.0 540.0 1079.93 196.35 196.35 392.7 540.0 540.0 1079.94 196.35 196.35 151.8 540.0 540.0 417.55 196.35 196.35 540.0 540.0 6 196.35 196.35 540.0 540.0

981.75 981.75 937.2 2,700 2,700 2,577

Air delivered (design) m3/s 7.96 8.34 9.89Air delivered (measured 2010) m3/s 8.16 8.77 10.37Air Delivered (setback) m3/s 5.97 8.09 7.56

ACH (design) 10.6 11.1 13.2ACH (measured 2010) 10.9 11.7 13.8ACH (setback) 8.0 10.8 10.1


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AHU 1 AHU 2 AHU 3 TOTAL20 20.5 30

73% 92% 73%10 3 1587,600 26,937 131,400 245,937£5,694 £1,751 £8,541 £15,986

47.65 14.65 71.48 133.79tonnes CO2 saved

Approx kW reduction based on Trilon email 15/9/10

kW of fan as foundReduction in volume

kWh reduction over year

Fan power savings

Electricity cost saving @ 6.5p/kWh

AHU 1 AHU 2 AHU 3 Total284,896 84,294 348,333 717,523

£5,698 £1,686 £6,967 £14,35052.42 15.51 64.09 132.02

AHU 1 AHU 2 AHU 3 Total7,625 1,852 7,652 17,128£496 £120 £497 £1,1134.15 1.01 4.16 9.32

AHU 1 AHU 2 AHU 3 Total292,520 86,146 355,985 734,651

£6,194 £1,806 £7,464 £15,46456.57 16.52 68.26 141.34

tonnes CO2

tonnes CO2

kWh£

kWh£

Boiler saving

Chiller saving

Total Heating & Cooling SavingkWh£tonnes CO2

AHU 1 AHU 2 AHU 3 TOTAL380,120 113,083 487,385 980,588£11,888 £3,557 £16,005 £31,450

104.22 31.17 139.74 275.13

Total energy savingkWh reduction over yearCost savingtonnes CO2 saved


Carbon Desktop - Electricity demand profile for Transformer 40 - MCP3 at SAF.

MCP 3 feeds AHUs 1,2,3, 4, 7,8,17,18,16,9 & 23.

A further £15K in heating and cooling savings using bin weather data.

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Continuous Optimisation – Filter Optimisation

Filter Optimisation


Filter Optimisation

• Most air handling units (AHU’s) have integral filter strategies, applied primarily to supply, and for some applications, the extract.

• Filter media provides significant resistance within the air flow path, resistance increases as filters become blocked.

• Higher resistance of the filter, results in increased energy consumed by fan motor to provide the required air flow.

• Initial trials (Carbon Trust Funded) in the SAF building have shown, that by using filter media (e.g. HiFlo bag filters) with a larger surface area, significant savings can be achieved on fan motor power.


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Bag Filters % installed at the IC (approx)

Energy Rating

Comparative Cost per filter

(£)

Details

S Flo - WU series 30% E £19.73Basic economic bag ~ 300mm deep

S Flo – WP series 50% E £18.23Basic economic bag ~ 500+mm deep

Opakfil Green 20% A £60.68Energy efficient “rigid” bagUsed at SAF

Hi Flo – M series 0% A £48.05

Energy efficient – high surface area bagNot used anywhere at IC yet.


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No Measure Implement Immediately?

Energy Savings (kWh/yr)

CO2 Savings

(tonnes/yr)

Energy Cost

Savings (£/yr)

Total Life

Cycle Cost

Savings - LCC (£/yr)

SAF 1 Replace HEPAs (H13 to H10) YES 50,430 27 £3,278 £3,278

SAF 2 Replace standard G4 panels with 30/30 panels (implemented) YES 64,347 35 £4,183 £2,574

SAF 3 Replace Opakfil Bags with Hi Flo and remove Panels NO - TRIAL REQ’D 138,325 5 £9,129 £8,037

253,102 67 £16,590 £13,889

No Measure Energy Savings (kWh/yr)

CO2 Savings

(tonnes/yr)

Energy Savings

(£/yr)

Total Cost

Savings LCC (£/yr)

1-10 All filters measures above 2,271,765 1,156 £146,710 £87,008


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NoMeasure

Implement Immediately?

Savings

Current Proposed Energy (kWh/yr)

CO2 (tonnes/yr)

Cost(£/yr)

Total Life Cycle Cost - LCC (£/yr)

1 HEPAs H13 HEPAs H10 MORE INFO REQ’D TBC TBC TBC TBC

2 Standard G4 panels 30/30 panels YES 252,217 137 £16,394 10,936

3 Pad filters 30/30 pleated panel filters YES 126,108 69 £8,197 5,468

4-6 300 mm Bags 600 mm Hi Flo Bags TRIAL REQ’D 464,447 247 £29460 13,691

7 S Flo (WU) & Opakfil (rigid) Bags

Hi Flo Bags (no panels) YES 87,938 48 £5,716 1,443

8 Change panel filters at lower pressure drop YES 252,217 137 16,394 10,936

9 Change bag filters at lower pressure drop YES 162,848 89 10,585 6,273

10 Improved filters &changing regime for AHUs < 15 kW YES 672,888 363 43,373 24,373

11 (SAF) HEPAs H13 HEPAs H10 YES 50,430 27 £3,278 £3,278

12 (SAF) Standard G4 panels 30/30 panels YES 64,347 35 £4,183 £2,574

13 (SAF) Opakfil Bags Hi Flo bags (no Panels) TRIAL REQ’D 138,325 5 £9,129 £8,037

2,271,765 1,156 £146,710 £87,008


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Hi flow bagS Flow bag

Opakfil Rigid bag

30/30 Pleated Panel

Continuous Optimisation – How does ICT support Continuous Optimisation?

How does ICT support Continuous Optimisation?

Continuous Optimisation – TREND System

TREND System (BMS)

• Imperial College has the largest TREND Building Management System in the UK (original installation commenced1996).

• Traditionally it has been used to monitor the operational status of plant & services and in particular, plant failure (replaced Sauter).

• This system was stand alone with a ‘hard wired’ network, which as it grew, became less reliable and access speed slowed significantly.

• To overcome these issues and future demand we now run the BMS over the Cat 3 network, which assures capacity, improves access and has increased reliability.

• This approach has allowed us to widen access via a web link, and start utilising it’s potential for improving sustainability through better control and awareness.


Electricity profile the week before the damper replacement and night setback initiation

Dampers replaced (Mon 5th & Tues 6th October)

Night set back initiated Wednesday 7th October

kW

400

320

240

160

80

Base load has reduced from 280kW to 210kW

Continuous Optimisation – Carbon Desktop

Carbon Desktop


Pre Set-Back Post Set-Back


Weekly range =0.4 tCO2

Pre Set-Back


Post Set-Back

Weekly Range = 0.8 tCO2

Continuous Optimisation – Real Time Logging

Real Time Logging

Continuous Optimisation – Real Time Logging

Real Time Logging

• Imperial College has spent over £1M in extending our metering capacity in the past 2.5 years.

• Despite this investment, this growth generally doesn’t extend itself to individual items of plant, which can make assessment of actual load, and any beneficial improvements difficult to monitor.

• We are introducing ‘Real Time Logging’ utilising meters with radio interfaces linking to an accessible website.

• This allows us to run real time trials e.g. AHU fan motors with filter changes and verify savings.

Continuous Optimisation – How does ICT support Continuous Optimisation?

• The use of these approaches, provide fundamental support to our ConCom programme and help to:

– Raise awareness within the academic community

– Demonstrate improved sustainable performance

– Validate data and savings


How are we achieving improved sustainability

Building Management

Academic Community

ICT Services

TOGETHER

continuous optimisation

Documents

air volume

reducing air pressures

air supply pressure

main air handling services

air changes hour

backgroundinitiatives

new controls

controlled environments