Monday, 31 December 2012

The 2050 office - a view from 2013.

Preparing for a series of workshops on energy efficiency in buildings I took another look at the 2050 Pathways tool[1] and was reminded of the importance of energy efficiency in the workplace as well as at home. This tool was developed by DECC for evaluating options to reduce our carbon emissions over the 2050 timescale and all of the example pathways include high targets for energy efficiency across all sectors. However, the base case for lighting and appliances assumes an increase in energy use up to 2050 - 20% more in homes and 35% more in the commercial sector. Is this reasonable? If you haven't decided on a new year resolution why not think about a campaign to save energy in the office.

Currently, commercial and public buildings consume 30% of UK electricity [2] and up to a half of this can be lighting and appliances, unless you have air conditioning. Also, the electricity used by appliances eventually becomes heat which adds to demand for cooling in summer - a desktop computer (65 W) plus a medium sized monitor (40 W) and general lighting (4 W/m2, or 40W/person in summer ) produces more heat than the person using them (typically 125 W). Giving your workers bigger monitors adds to your air conditioning costs as well as the direct electricity use.


Office electricity consumption, scenarios from Strathclyde Univeristy [3]
Engineers from Strathchlyde University [2] modelled two potential scenarios for future offices based on current trends summarised in the chart. The energy conscious scenario halved energy consumption - mainly by
  • using thin clients instead of desktop workstations (65 W down to 11 W)
  • limiting workers to only one monitor, of the best efficiency available (36 W down to 18 W)
  • replacing the VoIP phone (5 W) by a smart phone
  • savings on lighting partly by using LEDs but also by turning lights off more at night and increasing desk occupancy so each person takes less space.
The techno explosion scenario on the other hand increased energy use by 50% - more even than than the 2050 Pathways base case sceario. They still had the thin clients, smart phones and efficient lighting. The increase was due to
  • more monitors and touch screens - dual 24" screens for each worker plus a 27" touch screen instead of a keyboard
  • a 'media wall' in meeting rooms - two 88" touchscreen panels, each consuming 3.6 kW when operational and responsible for a third the overall electricity consumption.


Both these scenarios assumed that the office would at last be paperless so that printers and copiers would be replaced by e-paper. This saves about 8% of the base case energy, mostly due to the copier. I would love to get rid of paper if only because it means less filing - we shall have to wait and see if e-paper technology will make this possible.

Also both scenarios assume a high occupancy ratio due to 'pervasive sensor networks'. These make it easier to decide whether to come into work or not and easier to find a spare desk when we do because we will all be hot desking. Without it a typical office has less than half its desks occupied at one time [4].

With my business head on I would not write off the techno scenario because of high energy cost. Electricity is expensive but people are even more so and bigger screens can increase productivity significantly. An extra 40W for one monitor costs less than 3p/day at current prices (8p/kWh for medium non-domestic tariff[5]). Even at 3.6 kW the media wall electricity costs only 29p/hour. However, I don't see the point in the touch screen in place a of a keyboard.

How, then, to save energy without sacrificing productivity? You've heard it before - turn things off when not in use. For this strategy you can deploy a range of tactics - involving direct control by workers or more automation.

Lighting


You come in the office in the morning and the sun is reflecting off your screen so you close the blinds and turn on some lights. An hour later, the sun is higher and has moved around so it isn't a problem any more - do you open the blinds then and turn off the lights? Perhaps if you weren't concentrating quite so hard on what you were doing you might get up, ask your co-workers if it is OK to raise the blind now, then find the light switch by the door and turn it off.

You can get lighting controls on timers, or which are sensitive to light levels, dimming down on sunny days and with people sensors so they turn off automatically when no-one is there. However, even with all that they won't raise the blinds automatically - and would you want them to?

If you go for mainly manual options, you need to make it easy for workers to manage the lights. That means you need the light controls to work in small banks with a switch close by so you can find it easily and so you don't have to trek past lots of other desks to adjust it. If you just have a big panel with lots of switches most people will give up trying to find the right one and just turn on everything.

You may need to leave some light on overnight for security, but very often more lights are left on than needed simply because no-one has established a policy. The Strathclyde University base case assumed 25% of lights were left on - 2 W/m2 which comes to 128 kWh/year/desk (assumes 9 hours/day 260 days/ year for normal working). In the future scenarios this was reduced to 10%.

Sleep and standby


Most monitors and computers now have energy saving features which can automatically blank screens, run down disks and slow the processor when nothing is happening - sleep mode can reduce power down to 5W or less, saving at least 95% of energy consumption. However these features only work when switched on and someone needs to check regularly that this is the case, or control it centrally. There are legitimate reasons for turning auto-sleep off sometimes - recently I left a big job running and came back some hours later only to find my computer had paused after 30 minutes because I hadn't been pressing keys . So I disabled the sleep to run my job - and forget to turn it on again for a week.

Copiers and printers are quite likely to use significant power even when on standby: a large copier typically uses 30W when idle, as much as five or six computers with monitors in sleep mode. Over a year, switching the copier off outside office hours saves nearly 200 kWh. This can be done automatically on a timer, though you will need an override switch for occasional out-of-hours use.


Dump the vending machine


A typical snacks or cold drinks machine consumes 90W even on standby (hot drinks machines are less because they don't have refrigeration except a little for the milk). If you have a small fridge and a microwave instead they would use only 20 - 30 W, saving more than 500 kWh/year [5].

Other ideas and further information


  • When buying new equipment always check the energy ratings - see Energy Star label for computers.
  • For your servers - make sure they have an efficient power supply. Look for the 80 plus standard (described here by hexus.net)
  • Again for your servers - don't set the A/C cooler than it needs to be. Most servers are quite happy up to 27C or even hotter.
  • Once a month or so run an after-hours check to see what has been left on which doesn't need to be.
  • Keep the fridge defrosted regularly and the kettle descaled just like you do at home.
  • For manuals and other texts that need to be updated regularly - make them accessible online so you don't need to keep printing them out.
There's lots more advice from other websites - such as the Carbon Trust and 2 degrees campaign.

Happy New Year everyone!


[1] 2050 Pathways DECC
[2[ Digest of UK Energy Statistics 2012 (DECC)
[3] Trends in Office Internal Gains and the Impact on Space Heating and Cooling James Johnston, Prof John Counsell, Dr P A Strachan, CIBSE Technical Symposium 2011
[4] Shrinking the Office (www.flexibility.co.uk)
[5] Quarterly Energy Prices Sep 2012 (DECC)
[6] Review of benchmarks for small power consumption in office buildings Menezes, Anna C. Nkonge, Noah Cripps, Andrew Buswell, Richard A. Bouchlaghem, Dino Bouchlaghem - BUILDING SERV ENG RES TECHNOL

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