Voltage Optimisation Webinar Phil Reid Head of Sustainable Design September 26 th, 2012
RED - A SNAPSHOT MEP Consulting Engineers 175 permanent staff with Continuing Growth 6 Offices in UK, Middle East and Asia Currently working in 22 Countries 18 Nationalities 15 Languages Turnover in excess of 8 million Sustained and steady growth since start in 2005 Sectors : Data Centres Hotels Retail Commercial Industrial / Process Telecoms Research / Laboratory www.red-eng.com
Voltage Optimisation Webinar - Advantages Reduction in power usage by linear loads Reduction of Harmonics in some cases can be resolved by installation of filters Reduction of Phase imbalance in certain cases proper electrical design of circuit loads will resolve this Protection against voltage spikes in some cases Voltage protection units should be installed as standard as part of main switchgear. www.red-eng.com
Voltage Optimisation Webinar The Pitfalls : Voltage Tapping Alternative Where the site has control over its own transformer, the simplest way of reducing voltage is by adjusting the tappings on the secondary windings. Good solution assuming incoming voltage is fairly stable and peaks and troughs are within % limits www.red-eng.com
Voltage Optimisation Webinar The Pitfalls : Bigger Volts drops If the voltage of the power supplies is reduced at source and there are large cable runs across the site, the voltage drops across the cables could be excessive with increased current draws. This may lead to problems with electric motors with a high starting current and possible damage to motor windings www.red-eng.com
Voltage Optimisation Webinar The Pitfalls : Lower output By reducing the voltage to an appliance, the power output will reduce accordingly. Although this will provide savings, in the case of lighting, the result will also be to lower the light levels in the room, which may or may not be acceptable to the building occupants. The same amount of energy is required to carry out certain functions irrespective of the voltage, some of these include : Boiling a kettle Maintaining temperature in a refrigerator Keeping a room at the correct temperature www.red-eng.com
Voltage Optimisation Webinar The Pitfalls : Lack of Data We have not, to date, been able to access any data, which shows Before and After energy consumption results under controlled conditions. To be of use, these need to be taken for the same building under the same operating conditions and over two years one without and one with VO technology www.red-eng.com
Voltage Optimisation Webinar The Pitfalls : Limited effect on Modern Building Whilst we acknowledge that by reducing voltage, power savings can be made in linear loads (eg: heater elements), most loads in modern buildings will not present any advantage. These loads include : IT Equipment Electric motors (exceptions such as induction motors under light load UPS Most lighting (except old style light fittings) Variable speed drives www.red-eng.com
Voltage Optimisation Webinar The Pitfalls : additional Losses The inclusion of the VO Unit in the incoming supply will result in equipment power losses Fixed losses and load (I 2 R) losses due to : Semiconductors Inductors Capacitors Diodes Switching losses Core losses Winding losses www.red-eng.com
Voltage Optimisation Webinar - Conclusion Advantages Linear loads power reduction Harmonics Power Factor Correction Phase balancing Transient voltage spikes Disadvantages Alter transformer tappings Increased voltage drops in cables Increased risk to motor damage on start-up Reduced outputs No energy savings in many types of equipment Lack of accredited data Limited influence on electrical services in a modern building Equipment losses www.red-eng.com
CONTACT US : SUSTAINABILITY TEAM PHIL REID HEAD, SUSTAINABILITY Red Engineering Design Ltd. 1 Lower Farm Barns, Bainton Road, Bucknell, OX27 7LT, UK tel +44 (0)1869 355 600 fax +44 (0)1869 250 777 mobile +44 (0)7584212819 email preid@red-eng.com ABU DHABI Contact: Mick Cairns Address: Red Engineering Middle East, Al Niyadi Building Unit 503, Level 5, Abu Dhabi, United Arab Emirtaes tel +97 14 286 8655 fax +97 14 286 8645 mobile +97 150 656 9957 email mcairns@red-eng.ae DUBAI Contact Brian Dryburgh Address Red Engineering Middle East Office No. 1403-1404 Al Shafar Tower, Tecom C Area, Dubai, United Arab Emirates tel: +971 4 447 7281 fax: +971 4 447 7253 email bdryburgh@red-eng.ae LONDON Contact Tony Purcell Address Red Engineering Design Ltd, 10 Fitzroy Square, London W1T 5HP, UK tel +44 (0)20 7874 1588 fax +44 (0)20 7388 8241 mobile +44 (0)7824 804 228 email apurcell@red-eng.com MANILA Contact: Ed Whitney Red Engineering Design Services, Inc. 11th Floor, Salcedo Towers, H.V. Dela Costa Street, Salcedo Village Makati City, Philippines tel +63 2 7531721-22 fax+63 2 7531828 mobile +63 999 353 0628 email ewhitney@red-eng.com.ph OXFORD Contact Ian Whitfield Address Red Engineering Design Ltd, 1 Lower Farm Barns, Bainton Road, Bucknell, OX27 7LT, UK tel +44 (0)1869 355 600 fax +44 (0)1869 250 777 mobile +44 (0)7770 944 138 email iwhitfield@red-eng.com www.red-eng.com
VO; The holy grail of energy efficiency? Rob Scoulding-the Co-operative Group
Background; The Co-op group has around 5,000 properties Every site is different. Our annual electrical bill is in excess of 100m pa Since 2006 we have reduced our CO2 by 35% and aim to have reached 50% by 2017 We have invested heavily in colleague engagement, asset renewal and Research and & Development Voltage Optimisation is seen as an important part of the toolkit to drive future savings We have 20 units currently installed. We have been working with Powerstar UK and PES
Voltage Optimisation Our observations It's not THE solution. It's a tool. Like anything else you'd look at any number of energy-saving solutions when you're looking at a site and aiming to save energy. This is just something to have in your toolbox. Consider it because in the right scenarios it can yield very significant savings. But there are instances where it can achieve nothing and ultimately will be a waste of your money. We have had over 60 sites surveyed-not all are worth doing
How VO works * voltage ation important? * With thanks to powerstar uk
The maths-ohns law* *thanks to PES
What did the Experts say? A 230V linear appliance used on a 240V supply will take 4.3% more current and will consume almost 9% more energy and only achieve 55% of its rated life Savings with Voltage Optimisation completely depends on the load the site has and therefore a full site survey is essential.
What were we told that VO could offer? Reduction in kw/hr consumption Reduction in CO2 emissions Prolongs lifespan of plant and equipment Reduces demand Improves power quality ( power factor )
VO will benefit all loads in the building. However that doesn't mean to say that it will save energy on every load in the building. Some equipment, for example high frequency lighting, will not realise a saving using voltage optimisation. Sites with a high voltage dependant load will benefit in terms of energy saving more than a site that is voltage independent. Some loads will achieve reduced savings such as motors with inverters, in which case the inverter is doing some of the work a VO system would and, unfortunately, you can't save energy twice. But that's not to say there won't be a benefit in these cases. Voltage optimisation systems increases the life expectancy of equipment. LED drivers are a good example. Designed to run at 220v if it received 253v it would be expected to wear out far earlier than if it were running at the voltage it was designed to run at. So there is a benefit but it's not always in pure energy savings.
Prolonging life-source ECA *
Harmonic Distortions Total harmonic distortions trace over 48 hours before and after the installation of a VO system Total current harmonic distortions are reduced by almost 50% Vo reduces the harmonic distortions. Excessive hamonic distortion can affect power factor on a system, currents flow back on the neutral. RECs monitor this and will charge accordingly ( <.9 )
The proof is in the..
Co-operative VO projects Co-operative Sites Analysis 20 units installed
Formula Verification For each site regression analysis has been applied. Using a program called R a model based on certain variables has been created. This model predicts how the consumption would have been without Voltage Optimisation. Then there is a post installation comparison between the actual data and model data. Variables used for the model include days of the week (i.e. consumption may be larger on a Friday than on a Sunday), Heating and Cooling degree days (The temperature may affect consumption) and a holiday variable (consumption may be less if the day is a
Cottingham- Fixed Unit Size: 226 kva Savings made: 10.8% kwh savings to date (estimated from model): 62,332 kwh Savings up to date 10/02/12 (using 11p kwh from proposal): 6,857
Cottingham - Graph
Garston-fixed Unit Size: 288 kva Savings made: 17.4% kwh savings to date (estimated from model): 184,600kWh Savings up to date 10/02/12 (using 11p kwh from proposal): 14,768
Garston - Graph
Irlams O Th Height-fixed Unit Size: 288 kva Savings made: 14.3% kwh savings to date (estimated from model): 82,725kWh Savings up to date 10/02/12 (using 11p kwh from proposal): 9,100
Irlams O Th Height - Graph
Ludlow-fixed Unit Size: 250 kva Savings made: 13.7% kwh savings to date (estimated from model): 151,252kWh Savings up to date 10/02/12 (using 11p kwh from proposal): 12,100
Ludlow - Graph
Worcestershire store-variable
Things that could go wrong Not all the necessary parties may turn up on time-or at all ( REC attendance ) The installation could take longer than planned. There can be occasions where individual circuits are not receiving adequate voltages and can require voltage step-up transformers.
Lessons learnt Choose the right partner-this is essential. Talk to the people who are going to do the surveys, the logging and the actual installations. They need to understand your sites as much as they understand their products. A thorough site survey is essential. Each site is quite different from the next. Careful co-ordination between all parties is essential; Installation teams,recs, store teams etc If you have fridges/freezers book a generator. Ensure your units have Under voltage relays fitted. Be very clear on your expectations regarding savings
What were we told that VO could offer? Reduction in kw/hr consumption Reduction in CO2 emissions Prolongs lifespan of plant and equipment TBC Reduces demand TBC Improves power quality ( power factor TBC )