New Ways of Working: Linking Energy Consumption to People

New Ways of Working: Linking Energy Consumption to People

Ken Dooley World Sustainable Buildings Conference October 2011

Behaviour change

Positive behaviour change:

• Provide comparision with ones peers

• All parties should be compared fairly

• A more just metric than kWh/m2 is required

Compare performance of:

• Buildings

• Departments

• People

Change !?!

World Sustainable Buildings Conference October 2011

Incentive schemes

Residential building example:

• A block of similar 2 bedroom apartments

• Incentive scheme to reduce energy

• Reward given to the lowest energy consumption over a period of time


Building energy breakdown

Directly related to building geometry

• Heating

• Lighting

Directly related to people only

• Equipment electricity

• Ventilation (fresh air)

Directly related to building geometry and people

• Cooling


Relating energy to area

”If you can’t measure it, you can’t manage it”

kWh/m2

• Design phase: good measurement of physical building properties

• Poor insight as to how buildings are used during occupancy phase

• Misleading when evaluating operating costs


An alternative metric

Wh/m2h, annual energy consumption per area per occupied hours

Where:

• kWh1/m2 is the annual energy consumption

• h2 known as total person hours, is the total number of hours that all occupants have spent in the building during the year in question


Occupation density

Energy directly related to people is not considered by area metrics

Average occupation density in UK offices is 11.8m2 per workspace1

• 77% of workspaces between 8m2 & 13m2 per workspace

• Using kWh/m2, 13m2 per ws. will seem more energy efficient than 8m2 per ws.

Productivity and comfort must be considered, however, it does not seem prudent to utilise an energy metric that encourages large amounts of area per person

1: Occupier Density Study Summary Report, British Council for Offices, June 2009

Source: Fooducate.com


Case study

•Simulated case study: office building in Helsinki

• Area: 4650m2

• Hours of occupancy 08:00 – 17:00 (9 hours)

Similar day lengths, different occupation densities

Results

• kWh/m2: case C consumes the least

• kWh/person or Wh/m2h: case A consumes the least

(C consumes 44% more than A)

Case A B C

Population density (m2/person) 8 10 12

Number of occupants 500 400 332

Energy consumption (kWh/m2) 102 99 98

Energy consumption (kWh/person) 951 1150 1368

Energy consumption (Wh/m2h) 0.087 0.105 0.126


Hours of occupation

Not considered by area metrics

• Comparison of two similar healthcare buildings

• Hospital ”A” open 24 hrs / Hospital ”B” open 12 hrs

• kWh/m2 does not provide an allowance for the longer day of ”A”

• Thus ”A” has a higher energy consumption per m2 and seems less energy efficient

By not providing an allowance for the number of hours a day a building is operated kWh/m2 offers a direct benefit to buildings that have shorter working days


Case study

•Simulated case study: office building in Helsinki

• Area: 4650m2

• Population density 10m2 / person

Similar occupation densities, different day lengths

Results

• kWh/m2: case F consumes the least

• kWh/person or Wh/m2h: case D consumes the least

(F consumes 45% more than D)

Case D E F

Working hours per day (h) 12 9 6

Hours of occupancy 08 - 20 08 - 17 09 - 15

Energy consumption (kWh/m2) 115 99 84

Energy consumption (kWh/person) 1330 1150 981

Energy consumption (Wh/m2h) 0.092 0.105 0.134



Dynamic occupancy data…

…how do we measure it ?

Monitoring occupancy

Access control system that supports the measurement of total person hours

Employees log in/out of the building via:

• Electronic time clock

• Smart phone

• Personal computer

• Real time location tags

A reporting system that defines location as a set of routines:

• Routine 1: out of the building

• Routine 2: in the building

Building

IN OUT


Concept development


Behaviour Change

Motivation / Incentives

Measure per Person

Technology

Smart Grid

Advanced Controls

Measure Wh/m2h

Advanced Presence Detection

Virtual Energy Prices

Advanced presence detection

Use presence knowledge to control energy consuming systems

Average office utilisation is typically only 45%

• 55% of the desks are empty at any one time Measuring the Benefits of Agility at Work, Regus, May 2011

Define location as a set of routines:

• Routine 1: out of the building

• Routine 2: in the building

• Subroutine A: at workspace (default)

• Subroutine B: in a meeting

• Subroutine C: at lunch

IN OUT

IN

Building

IN OUT OUT


Use presence to control

Use presence knowledge to control:

• Shut down an individual’s workspace if they leave the building

• Set to standby an individual’s workspace if they are in a meeting / at lunch

• Shut down a lighting / ventilation zone if all of the occupants are out of the office

Presence Detected

Desk Lighting ON

Common Lighting ON

Equipment ON

Ventilation 100 %

Heating 21oC

Cooling 25oC

Example zone control modes:







Presence Detected

No presence 15 mins

Desk Lighting ON OFF

Common Lighting ON ON

Equipment ON STAND BY

Ventilation 100 % 100 %

Heating 21oC 21oC

Cooling 25oC 25oC








Presence Detected

No presence 15 mins

No presence 1 hour

Desk Lighting ON OFF OFF

Common Lighting ON ON OFF

Equipment ON STAND BY STAND BY

Ventilation 100 % 100 % 50 %

Heating 21oC 21oC 20oC

Cooling 25oC 25oC 27oC








Presence Detected

No presence 15 mins

No presence 1 hour

No presence 2 hours

Desk Lighting ON OFF OFF OFF

Common Lighting ON ON OFF OFF

Equipment ON STAND BY STAND BY OFF

Ventilation 100 % 100 % 50 % Night time mode

Heating 21oC 21oC 20oC Night time mode

Cooling 25oC 25oC 27oC Night time mode



Next Steps

• Pilot projects

• Today’s innovation and transparency: real time energy is reported

• Tomorrow’s innovation and transparency: Wh/m2h

• An alternative route to measure energy for

• Building regulations

• Energy certificates

• Limitations

• Different building types

• Wh/m2h works best for private buildings when there is a security barrier


Summary

An alternative energy consumption metric:

• Wh/m2h = kWh/m2 ÷ total person hours

• Enabling a fairer comparison of consumption to encourage positive change

• Does not punish buildings for incorporating an efficient occupation density

• Does not punish buildings for incorporating a longer working day


Thank you!

Ken Dooley Sustainability Group Manager Olof Granlund Oy Helsinki Twitter: @sustaingranlund Email: [email protected]


New Ways of Working: Linking Energy Consumption to People

Environment

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