IMPROVING COLD STORAGE AT
KING’S COLLEGE
School of Biomedical Sciences
Allison Hunter
Waterloo Campus and Guy’s Campus
Guy’s Campus (and the Shard)
New Hunt’s House
How much energy are we using? £80,257
Takes time
Consistent way of recording information
Type of energy monitor – ease of use
Staff – audit number and types of freezers
Cold storage units:
New Hunt’s House (NHH) 500
Franklin-Wilkins Building (FWB) 300
-80°C freezers
Equipment
Make
Model
kWh/ day
Freezer -80°C
NBS
U535
13.3
NBS
U535
14.4
Heraeus
Herafreeze
21.2
Heraeus
Herafreeze
19.6
Nuare
Glacier
19.3
NBS
U570 Premium
11.5
Haier
DW-86L388
12.0
Freezer -70°C
-20°C Freezers
Equipment
Make
Model
kWh/ day
No frost
Temp/
Capacity
-20°C/400litre
Freezer -20°C
Liebherr
Freezer-20°C
Liebherr
Premium
-20°C/400litre
1.23
Freezer-20°C
Liebherr
Premium
-20°C/200litre
1.15
Freezer-20°C
Electrolux
-
-20°C/200litre
1.60
Fridge Freezer
Liebherr
Comfort
+4°C /-20°C
0.59
1.17
Housekeeping measures
Once per month -De-ice with a scraper
-Clean the foam grill in front of the compressor
Ask staff to minimise door opening
Defrost every six months to a year in back up freezers
Offer dry ice service to sort freezer stocks
One unit in; one unit out
Advise leavers to discard or redistribute stocks
Rack or SLS FRE2130 £30 for 12 box FRE2228 Grid Divider
Equipment alarm system – freezers running too cold
T-scan equipment alarm
How can we reduce the energy we use?
Savawatt
http://www.savawatt.co.uk/images/db/dt_casestudies/9/casestudy.pdf
NHH
Current total cold storage energy spend £80,257
485 units were fitted costing £32,692 or £67.41 per unit
This saves 67.87 tonnes CO2 and £15,783.08 per year (20%).
(icemakers; 4°C incl cold rooms; 4°/-20°C & -20°C only)
Savawatt Control
Funding for Savawatt devices
Salix
http://salixfinance.co.uk/
Revolving Fund with a minimum and maximum spend each year
Loan Scheme which can be used to fund other projects
What else can we do?
Change freezer temperatures
-80°C freezers vary between 14-21 kWh/day
-70°C reading is 12kWh per day
Present data on energy consumption to staff (talk then email)
Cascade to divisional staff and students
Voluntary reduction not compulsory
Tech staff liaise between groups to alter settings on shared
freezers
Individual freezer costs
-80°C
U570HEF
NBS -80°C (one model)
Revco
-70°C
Haier DW-86L388
cost per annum
£306
£562
£850
£438
Outcome of freezer temperature request
Freezers
The total number of freezers reduced from -80°C to -70°C is:
19 (FWB 12 and NHH 7)
about 30% of our collection.
We have a total of 63 low temperature (all originally -80°C)
freezers in two buildings: New Hunt’s House (NHH) has 38 and
Franklin-Wilkins Building (FWB) has 25.
Freezer numbers
FWB 12 out of 25
NHH 7 out of 38
-70°C/-80°C freezer costs in NHH & FWB
Number of
Cost of
days electricity(£)
Cost per
annum (£)
Number of
freezers
Cost per
annum(£)
x .1
642.40
x63
40471.20
x 365
x .1
642.40
x 44
28265.60
x 365
x.1
438.00
x19
8322.00
Freezer type
kWh/day
minus 80°C
17.6
x 365
minus 80°C
17.6
minus 70°C
12
36587.60
minus 70°C
12
x 365
x.1
438.00
saving
£3,883.60
x63
27,594
saving £12,877.20
Cost comparison of running 19 units
in £ per year
14,000.00
12,000.00
10,000.00
8,000.00
6,000.00
4,000.00
2,000.00
0.00
-80°C Freezer
-70°C Freezer
Tonnes of CO2 produced by 19 units
60
50
40
30
20
10
0
-80°C freezer
-70°C freezer
How to work out CO2 usage and savings
minus 80
minus 70
6424
4380
kWh
x0.48357
x0.48357
defra factor
3106.45kgCO2
2118.04 kgCO2
sub total
x 44
x19
freezers
136683.95 kgCO2
40242.70 kgCO2
total
40242.70 kgCO2
18779.85 kgCO2
40.24 tonnes
18.78 tonnes
x19
59022.55 kgCO2
59.02 tonnes CO2
Minus
C02
http://www.theccc.org.uk/tackling-climate-change/reducingcarbon-emissions/what-can-be-done/
Search defra carbon conversion factors 2013
http://www.ukconversionfactorscarbonsmart.co.uk/
For the above I used the Defra carbon conversion factor of
0.48357 kgCO2/kWh. For cost, I would normally use 10 p/kWh as
that’s the current total cost including all charges.
Summary of cost and CO2 savings
NHH
£
Total previous cold storage
spend
80257
Savawatt controls savings
-15783
subtotal
64471
-80°C to -70°C savings on 7
units
1430
Current cold spend
63044
£80257 minus £63044
=
Tonnes C02
67.86
17,213
FWB
-80°C to -70°C savings on 12
units
=
Total savings in NHH & FWB
2453
18.78
£19,666
86.64
Can you reduce your freezer requirements?
Flinders University
http://www.nfstc.org/pdi/Subject03/pdi_s03_m04_02_d.htm
Supplier
http://www.whatman.com/NucleicAcidandProteinSamplePreparat
ion.aspx
Franklin-Wilkins Building
Collaboration
Technical
managers
Environmental
waste
Technicians
Estates and
Energy
Academics
and
researchers
Procurement
and
Purchasing
Hodgkin Building
Roll out to other buildings
The proposed batch of 147 Savawatt controls for:
Hodgkin Building,
Henriette Raphael,
Shepherd’s House and
Britannia House
are expected to save 23 tonnes CO2 and £4,751.41 per year.
Current cost=£24,092.48
Other estate includes Wolfson Wing, Hospital Trust embedded
space at Guy’s and St. Thomas’, Denmark Hill Campus
Conclusion
Audit
Record
Identify the quantity of high ticket items
Consistent recording
units kWh/day; calculate CO2
Building electricity meters
Reduce consumption Talk to staff, email follow up
Savawatt saves 20% energy
Freezers at -70°C saves 20-30% energy
Alternative storage
Funding
Salix; Estates
Total lifespan costs Energy usage and waste disposal costs
Thanks
Technical staff:
Carlos Roncancio-Garcia
Pranetha Baskaran
Stuart Fleming
Kelvin Howell
Estates:
Keith McIntyre
Lisa Ward
Kat Thorne
Tristam Slater
Resource Managers:
Jo Cunningham
John Darker
Steve Franey
Will Heal
Rosie Calokatsia
Dave Stanton
Sarah Meredith
Richard Davies
Colin Chinnery (Purchasing)
Allison Hunter
Deputy School
Resource Manager
King’s College London
Tel 020 7848 6163
Email allison.s.hunter@kcl.ac.uk
SavaControls: How they work
SavaControl
Power In
Solid State
Switch
Compressor
The solid state switch switches for a longer or shorter time, depending on
the load on the motor, 100 times a second
SavaControls: What are they
Electronic controllers which reduce the
electricity used by electric motors when
operating under part load conditions.
They do this in two ways, by:
1. Improving the motor efficiency
2. Modulating the power input according to
the motor loading.
Savawatt calculations
Refrigeration is never switched of and compressor run times will vary depending on type of equipment, what it is used for, how often
the door is opened, how old it is etc. We take an average compressor run time as sixteen hours per day of which 80% of the time the
motor will be in a part load condition. (part load is when the SavaControl reduce consumption)
The formulae for annual electrical consumption is: amps x volts x hours run x power factor =kWhrs per annum
1000
With numbers of a simple -20 freezer = 1.3amps x 240 volts x 4672 (80% of 16x365) x 0.8 (compressor motor power factor) =
1166kWhrs per year
1000
SavaControls will save 20% per annum on single phase applications. On the above the saving will be 233kWhrs, based on an
electricity cost of 10p/kWhr a saving of £23.32 per annum will be achieved. The basic SC3 @ £34.00 (plus installation) offers a
payback around 1.5 years.
SavaControls: How they work
The effects of SavaControls on the Voltage and Current Waveforms
No SavaControl
Energy Consumption 100%
With SavaControl
Energy Consumption 80%
Approximately 20% Savings!
-80°C to -70°C cost savings calculations
-80°C freezer at 17.6 kWh per day x 365 x .10p kWh =£642.40 x 44
freezers = £28,265.60 per annum and 136.68 tonnes CO2
-70°C freezer at 12.0kWh per day x 365 x .10p kWh = £438.00 x 19
freezers = £8,322.00 per annum and 40.24 tonnes CO2
Total cost saving per annum by reducing temperatures on 19
freezers has been £3,883.60 (Cost of 19 freezers at -80°C at 17.6
kWh per day x 365 x .10p kWh =£642.40 x 19 = £12,205.6)
Total CO2 reduction 18.78 tonnes (19 -80°C freezers 59.02 tonnes
CO2 compared to 19 -70°C freezers 40.24 tonnes CO2)
NHH -80°C to -70°C cost savings for 7 units
Number of
Cost of
days electricity(£)
Freezer type
kWh/day
minus 80°C
17.6
x 365
minus 70°C
12
x 365
Cost per
annum (£)
Number of
freezers
Cost per
annum(£)
x .1
642.40
x7
4496.80
x.1
438.00
x7
3066.00
saving
£1430.80
FWB -80°C to -70°C cost savings for 12 units
Number of
Cost of
days electricity(£)
Freezer type
kWh/day
minus 80°C
17.6
x 365
minus 70°C
12
x 365
Cost per
annum (£)
Number of
freezers
Cost per
annum(£)
x .1
642.40
x 12
7708.80
x.1
438.00
x12
5256.00
saving
£2452.80
Drying cabinets
FWB 5.118
one cabinet measured at 14.3 kWh/day
Timers on at 7am and off at 7pm would save:
14.3 x 0.5 x 3 cabinets x 365 days= 7829 kWh p.a. (x.10p kWh =
£780 per annum in one lab alone) and 3.78 tonnes CO2.
FWB 5.48 one drying cabinet uses 42.78 kWh/day
1.78 kWh X .10pkWh = 18p or £1.78 for 24 hrs or x365 days =
£649.70
By using a 12 hour timer we would save £323.96 per annum and
4.04 tonnes CO2.