Understanding the savings
Statement
Turning down the heating by just 1°C could save enough money to fuel a company car for 10,000 miles!
Assumptions
Reducing the thermostat by 1°C to stop overheating can save 8% on energy bills. A standard air conditioned office’s (type 3) heating and hot water use is
typically 178kWh/m2. Taking an office size of 600m2 total heat use is 600m2 x 178kWh/m2 = 106,800kWh. Therefore a 1°C reduction on the thermostat would
save 8,544kWh of heat. Source: http://www.cibse.org/pdfs/ECG019.pdf
Calculations
For heating
Heat energy use
Office size Energy use
Saving
178kWh/m2/per year
600m2
106,800kWh/per year
8%
8,544kWh/per year
Car
Car mpg
50mpg
11.02 miles per litre
Energy content of petrol
45.8MJ/kg
or
33.7MJ/litre
or
9.36kWh/litre
1.18 miles/kWh
Miles covered
10,051.8961
Source: http://www.acea.be/news/news_detail/what_are_the_main_differences_between_diesel_and_petrol/
Statement
Cleaning condenser coils in a bulk milk tank can save enough energy to heat a parlour wash tank, once a day for six weeks.
Assumptions
Dairy farm with 200 cows each producing 8,000 litres of milk per year. Total milk cooling requirement – 1.6m litres of milk per year.
“Cleaning a blocked condenser will improve compressor efficiency and save you at least 5% in energy.” A direct expansion tank cools 75 litres of milk per kWh.
Sources: h
ttp://www.carbontrust.com/media/13055/ctg046_refrigeration_systems.pdf
http://www.dairyco.org.uk/resources-library/d-archive/buildingsheat recovery-from-refrigeration-systems/ page 75 table 15
Calculations
Refrigeration saving
Farm size
Milk yield Annual milk produced
DX tank cooling capability
Cooling consumption
Saving from cleaning coils
Annual energy saving
Water heating
200 cows
8,000 litres per cow per year
1,600,000 litres per year
75 litres per kWh
21,333.3kWh/per year
5% saving
1,066kWh per year
Milking parlour points
Litres of washing water per point
Temperature lift of water
Heat required per day
Number of days hot water
16 points
18 litres/point
75oC
25.08kWh
42.50399 days
Statement
Switching off an air compressor at night and weekends could save enough energy to drive three forklift trucks
from Land’s End to John O’Groats.
Assumptions
An average compressed air system wastes around 30% through air leakage. If the system is switched off during out of work times (120 hours per week) leakage
and pressure related savings will be reduced by 120/168 x 30% = 21.4%. Based on a small industrial premise which uses 18kW compressor at 50% load factor.
Source: http://www.carbontrust.com/media/20267/ctv050_compressed_air.pdf Forklift truck = Hyster E1.6. Sources: http://viewer.zmags.com/publication/f140976b#/f140976b/1 http://accoblobstorageus.blob.core.windows.net/literature/730ed2f2-d80c-410f-9607-2fdd40f160b3.pdf
Land’s End to John O’Groats distance = 1,407km. Source: http://www.theaa.com/route-planner/index.jsp Calculations
Compressor calculations
Ratings Hours to shut down/week
Consumption on normal
operation at 50% load factor
Working hours per week
kWh wasted (based on 30%)
Wastage out of
normal working hours
Wastage over year Forklift
18kW
120
432kWh/week
48
129.6kWh/week
93kWh/week
4,814kWh
Max speed
Motor rating
Distance forklifts will do on waste
Land’s End to John O’Groats distance
Number of journeys 18.4km/h
18.4kW
4,814km
1,407km
3.57
Statement
Switching off a vending machine when everyone goes home saves enough energy to shred 1.1 million
sheets of paper – that’s 650 copies of the whole Harry Potter series!
Assumptions
A vending machine left on standby overnight and at the weekends consumes 300W. Source: http://www.cibse.org/pdfs/GPG118.pdf
A Rexel office shredder is capable of shredding 3 sheets per minute. Its power is 270W, therefore use per sheet is 0.0015kWh.
Source: http://accoblobstorageus.blob.core.windows.net/literature/730ed2f2-d80c-410f-9607-2fdd40f160b3.pdf
Calculations
Light calculations
Vending machine standby
Hours to shut down per week
Per year
kWh wasted
Shredder calculations
300W
108
5,616
1,684.8kWh
Rating
Paper rate
kWh per page
Paper shredded in a year
0.3kW
3 pages per minute
180 per hour
0.00150kWh
1,123,200 pages
Harry Potter books
659.35
Statement
Switching off the drinks chillers overnight could save enough money to keep the sound system playing for
two and a half months!
Assumption
Drinks display cooler consumption is 13.9kWh/24hrs.
Source: http://www.tefcold.dk/index.php?option=com_content&view=article&id=377%3Asldg800&catid=2%3Abottle-display&Itemid=116&lang=en
A Wurlitzer One More Time juke box 230V, 4A = 0.92 kW. Source: http://www.gibson.com/files/Wurly/pdf/OneMoreTimeVinyl.pdf
Calculations
Drinks cooler calculations
Daily consumption Hourly consumption Hours to shut down Days to shut down kWh saved
Juke box calculations
13.9kWh
0.579
8
365
1,691
Rating
Hours operation from saving
Days operation from saving
Months 0.92kW
1,838.2h
76.6 days
2.6
Statement
Converting to low energy lighting could save enough energy in a year to bake 1,500 large bread loaves –
that’s a lot of dough!
Assumptions
A small retail unit might have 10 x 1.5m twin fluorescent tubes with switch start - circuit watts 142W. Replace these with electronic start tubes - circuit
watts 107W. Source: http://www.apollolighting.co.uk/products/Technical/Control%20Gear%20Table/
A Bongard Omega 2 184 4-deck commercial bread oven has electrical connection of 76.9kW with electromechanical control and steam generator. It can
bake 12kg of dough/m2/h and has a baking area of 9m2. Therefore it can bake 12 x 9 = 108kg/h.
Source: http://www.bongard.fr/index.php?/en/Omega-range-Electric-deck-oven/Omega2-2-voies-de-800-mm/flypage-rouge.tpl.html From the savings of 2,920kWh, it can run the oven for 2,920/76.9kW = 38 hours. 108 x 38 = 4,100kg of dough input. Weight losses of about 12% occur through
baking. There is 800g in a large loaf. Source: http://www.thefreshloaf.com/node/4140/one-pound-loaf-flour-weight-or-dough-weight
Oven calculations
Lights calculations
Number/quantity
Wattage old
Wattage new
Hours operation based on 9 hours per day
6 days per week
kWh saved
10
142W
107W
2,808
982.8
Helping our customers.
We’re on it.
Rating
Dough loading
Baking deck area
Hourly dough output Hours operation on saving
Dough baked
Weight loss Bread baked
Weight of large loaf Loaves baked
76.9kW
12.0kg/m2/h
9m2
108kg
12.8h
1,380.3kg
12%
1,214.6kg
0.8kg
1,518.3