Optimising Energy

Performance of Water

Supplies

Paul Kenny, B.E. C. Eng.

Chief Executive

Tipperary Energy Agency

WARES

SEAI Energy Show

• €60M spend nationally excl. DBO

• Pumps, blowers and aerators

• Opportunities 20% - 30% from 2009 SEAI report

• Renewable generation a key opportunity

• Significant organisational Change

• How to achieve opportunity?

Context

• Pumps

• Poorly sized

• Design Vs current operation

• Demand change

• Improved technology

• Aeration Systems

• Poor O2 transfer efficiency

• Improved design

• PE Changes

• Renewable electricity

• Demand and Cost reduction

Key Opportunities

Pumps

• Centrifugal pumps are very simple

• Each pump is best of a specific flow and

head

• The wrong pump could be doing a job

perfectly well – except cost being higher

• How do you know?

– Calculate & compare

– Manufacturers pump data

– Review market best practice.

© TEA. www.tea.ie

Case Study

Recommended Max Op Pt @170 m3/h

Recommended Min Op Pt @140m3/h

Current Op. Pt

25.00

30.00

35.00

40.00

45.00

50.00

0m3/h

20m3/h

40m3/h

60m3/h

80m3/h

100m3/h

120m3/h

140m3/h

160m3/h

180m3/h

200m3/h

220m3/h

240m3/h

260m3/h

280m3/h

m

Oughterard Hi-Lift Pumping System Curve Step Control Recommended Operating Points

Head Loss Vs Flow Rate

Good Practice Pump

Author: Enda McGovern, TEA

Throttling

• Throttling is “creating artificial head”

• Valves partially closed

• Ballcocks at reservoirs – bell-mouths

better.

• Non return valves - faulty, undersized.

• Eliminate with VSD either

© TEA. www.tea.ie

Sewage Pumps

• Impellor choice critical – Balance between Energy Eff & Blocking

– Wear a big issue – keep well maintained

– Good selection critical

• Warning signs: – Increased amps without blockages, Decreased flow rates

– Excessive vibration, Any electrical trips etc.

– Overheating

• Replace

– New WW pumps improved massively over last 3 years

– 5-10 year lifespan

– Ragging excessively.

– Energy savings often pay for new pump in months.

© TEA. www.tea.ie

• Goal: Minimise total system life cycle energy

efficiency

• Understand system constraints (pipe size,

chlorine retention etc).

• Size pump accurately – should not be done by

the market.

• Identify other optimisation

• Procure on life cycle

Sizing & Procurement

Implementation

• Detailed Energy Audit: – Monitoring and design of actual duty Pressure/ Flow

– Ancillary system design/ requirements

– Understanding full system efficiency not pump only.

– PSAT / ASME-EA2 (Draft ISO) Optimisation.

• Opportunity/ Business case

– Best practice requirements

– Controls and optimisation

• Implementation

– Procurement on life cycle assessment

– EPC accountability

– Engineering time invested pays

© TEA. www.tea.ie

Results

© TEA. www.tea.ie

Results

© TEA. www.tea.ie

Energy Performance Indicator

WSNTG

0

0.1

0.2

0.3

0.4

0.5

0.6

10612

40612

70612

100612

130612

160612

190612

220612

250612

280612

10712

40712

70712

100712

130712

160712

190712

220712

250712

280712

310712

30812

60812

90812

120812

150812

180812

210812

240812

270812

300812

20912

50912

80912

110912

140912

170912

200912

230912

260912

290912

kWh

/m3

Date

Aeration

• Efficiency by maximising oxygen transfer

efficiency and use

• Minimise excess O2 through controls –

load to demand.

• Maximise transfer efficiency

– Fine bubble diffusers: Smaller bubbles,

slowest assent

– Maximise mixing

– Area of output

© TEA. www.tea.ie

Killarney WWTP

Replacement of the horizontal oxygenation rotors

with Fine Bubble Diffused Air System.

• Project Cost €122,000

• Estimated Saving in 2009 - €45,000

• Ditch capacity increased by over 30%

• High maintenance rotors removed.

• 1.93 kWh/kg BOD before

• 0.82 kWh/kg BOD after

58% Less

Renewable Energy

• Hydro Wind Solar PV

• Hydro needs high input pressure

• Wind needs high site

• Solar needs a big roof/ area

• Export rates low currently and need either

base load or large scale.

© TEA. www.tea.ie

Case Study

• Carna Cill Chiaran

– Pump Efficiency 25% Plant Reduction

– Constant Pump VSD Vs start stop

– 20kW base load wind turbine.

– 32% capacity factor to date

• Combine~40%

© TEA. www.tea.ie

• Non profit, public good enterprise

• Partnership approach

• Energy management

• Renewable energy and energy

efficiency

• Procurement, project mgmt.

• Cost effective, value driven

• Paul Kenny

• Chief Executive

• T: 052 7443090

• F: 052 7443012

• E: pkenny@tea.ie

• W: www.tea.ie

Tipperary Energy Agency