Energy saving cold storage

- Delivering world-class solutions for insulation of Cold Stores and Food Processing Plants

Energy saving cold facilities

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Operation costs in a cold facility

• Typically energy consumption account for a substantial part of running a cold facility• This substantiates the need for lowering energy consumption

26%

10%

41%

9%

14%

Energy Other Salary Administration Rent

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Several areas can be considered when lowering energy consumption in a cold facility.

• Insulation panels• Strip curtains• Air curtains• Doors• Loading docks• Light fixtures • Refrigeration system • Day-to-day basis

CT-technologies can provide the above products/services

Purpose

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Insulation panels

Bad building insulation (walls, floor, ceiling) negatively affects room temperature. This results in:

1. High energy consumption2. Reduction of frozen food shelf life 3. Lower food quality4. Frost build-up

Frozen food shelf-life

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Bad insulation

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Insulation panels: Case study

Details:

• Energy saving when replacing 100 mm PU panels with 200 mm PU panels from CT-Technologies • Room size: 2000 m3

• Cold store room: -25°C

• Outside cold store room temperature: +35°C

• ∆t: 60

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Insulation panels: Case study cont.

Result and notes: • Replacing 100 mm panels with e.g. 200 mm panels will save energy costs by USD7756 per year in a

2000 m3 cold room • Heat loss through a cold facility’s roof is higher than anywhere else. Therefore, 200mm + 100mm

panels can be installed for even higher energy savings

* (assuming $0.17 per kWh)

100 mm PU panel 200 mm PU panelHeat transfer coefficient 0.23 (W/m2/K) 0.12 (W/m2/K)

Heat loss through walls (24hours and room at -25°C) 262 kWh 137 kWhEnergy saving when using 200mm instead of 100mm (24H) 125 kWh

Energy saving per year ($) * $ 7756Panel price per m2 (incl. shipping) 36 USD 57 USDTotal price for 2000m3 cold room $28512 $45144

Payback period when choosing 200mm panels 5.8 years

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Strip curtains

Excessive door openings can result in excess use of energy and may affect temperature control within a cold store

Source: ICE-E (2014)

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Details:

• Cold room storing uncooked pies• Desired pie temperature: 3-5°C• 2 doors without strip curtains

Problem:

• Pie temperature reaches 12°C during operation hours **

• Heat infiltration through doors responsible for 68% of heat load on the store ***

Strip curtains: Case study

Case study: UK pie factory, lack of strip curtains*

Solution:

• Install strip curtains on doors. CT-technologies use high quality strip-curtains for minimum heat loss

• Installing strip curtains saved 19% of the energy used by the cold store (from 5.3kW / day to 4.3kW / day) ****

• Pie temperatures were kept at desired level of 5°C

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Strip curtains: Case study cont.

Temperature of pies in cold store with strip curtains.

Temperature of pies in cold store with no door protection.

Air curtains

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Using CT-technologies’ air curtains is an effective way to combat warm air infiltration and thus save energy

Air curtain benefits:

1. Reducing heat loss by up to 80%

2. Energy saving: 1-10 %

3. Energy savings generally pay for the equipment

and installation costs within 1-3 years

4. Maintains visibility and safety

5. Improves sanitation

Source: Berner (2013)

Air curtains cont.

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Doors

Problem:

Slow speed/manual conveyor and forklift doors allow large amounts of infiltration due to the length of time the doorway is open during the operation cycle = higher energy bills.

Solution:

Replacing an old, slow moving door system with a modern, high-speed door system (with the latest technology) from CT-technologies results in significant energy savings.

Source: Cold Chain, 2014

Doors: Case study

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General refrigeration data Measurement Infiltration air temp. (average) 27°C

Infiltration space humidity 70%Refrigerated space temp. -28°C

Refrigerateted space humidity 5%Day per week 7

Door opening per hour 12.5 timesOperating hours 8.76 hours

Refrigeration type 1 kw/ton

Door specification12 inch / Sec.

door60 inch / Sec. Door

Measurement

Door height 305 305 cmDoor width 244 244 cmDoor area 2438 2438 cm2Hold time 6 6 seconds

Opening speed 30.5 152 cm/secClosing speed 30.6 153 cm/sec

Total door open time 22 9 secondsAverage refrigeration load 160,52 67,00 kWh

Energy use, general refrigeration 399,120 166,905

kWh / year

• Energy saved per year: 233,132 kWh• $39,632 per year (assuming $0.17 per kWh)*

Comparison: 12 inch/second door with 60 inch/second door*

Loading docks and operation

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Problem:The time taken to load and unload products a cold store affects:

• The amount of hot and humid air infiltrated through the doors • Heat gained by the products in the meantime (which may lead to their deterioration)• Increased number of necessary defrost cycles (due to extended door openings)= All equal to higher energy bills

Solution:CT-technologies’ design ensures minimum electricity consumption by:

• Reducing heat infiltration into cold store by installing air curtains on the doors• Designing ante-room (cooling down air in the ante-room outside the frozen rooms to e.g. 5°C) • Adding mechanical cooling in the loading dock.

Source: ICE-E (2014b)

Loading docks and operation: Case study

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• A case study from an ice-cream factory in Bulgaria showed 8% energy saving by implementing CT-technologies’ design standards explained earlier.

Comparison of expected energy savings and required investments for different solutions to reduce

heat loads from infiltration through the cold store docking

area and doors. kWh saving / month = 150.000

Light fixtures

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Problem:• Traditional lights installed in a cold facility have high heat energy• Because of the heat from the lights, the chillers need to remove the energy created by heat

from the lights to keep a low temperature in cold storage

Solution: • Replacing traditional lights with CT-technologies’ HIF/LED lights/Led lights with intelligent

control will save a substantial amount of energy usage.

Light fixtures: Case study

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• In a – 26C° Cold Storage 50 x 250W sodium lamps were replaced on a one-for-one basis with 50 x 48W LED light fittings

• 80% reduction in energy consumption

• Assuming a 24/7 365- day operation, the annual energy saving would be 175,000 kWH

• Or $29,750 in energy saving/annum (assuming $0.17/kWh)

• Carbon emissions will also be reduced by 94,000 tons per annum

• Additionally, the LED lights will contribute to more room brightness (see image)

Before LED light After LED light

Souce: Savenergi, 2014

Refrigeration system

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The energy cost above call for high quality refrigeration systems to reduce energy costs.

Sector Proportions of energy costs that can be accounted for by

refrigeration

Meat, poultry and fish processing 50%Ice cream manufacturing 70%

Cold storage 90%Food supermarkets 50%

Refrigeration system cont.

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Choosing refrigeration equipments such as: • Compressors• Condensers• Air coolers• Chiller units• Ice handling equipment• Freezing equipment

saves a substantial amount of energy.

CT-technologies has years experience in supplying and selecting the best industrial refrigeration equipment from the industry’s leading manufactures.

Refrigeration system cont.

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Reducing condenser temperature is key to saved energy bills.

Energy savings in % by reducing condenser temperature 1°C

Refrigeration system cont.

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Appropriate condenser size: • Increasing condenser size to match cold room facility results in up to 10 % energy saving *

Evaporators: another key area to reduce energy consumption: • Evaporaters with intelligent defrost control saves energy consumption by 9%.

• Evaporators with low fan horsepower can save up to 25% on energy bills **

The importance of piping insulation not to be neglected:***

• CT-technologies can advise on piping insulation (e.g. how thick insulation needs to be) • Well insulated piping system can reduce costs by 5%. ****

Source: Carbon Trust (2015)

Refrigeration system cont.

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High quality refrigeration equipment and well-operated refrigeration plant can reduce energy consumption by 50% or more.

For instance:

1. Use a central system with a few large industrial type compressors.

2. Use of state of the art fans, motors, lamps etc. with ultimate efficiency.

3. Evaporative condensers rather than air cooled types.

4. Oversized evaporator and condenser surfaces enables compressors to work

with high evaporating and low condensing pressures with consequent low

wear and low energy consumption.

Source: Carbon Trust (2015)

Energy saving on a day-to-day basis

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CT-technologies can advise on how to save energy on a day-to-day basis. For instance*:

1. Optimise air flow for refrigeration equipment: Energy saving: 5%

2. Correctly stock display cabinets: Energy saving: 3%

3. Fan controls on large refrigeration units: Energy saving: 1%

4. Switch lights off when not needed: Energy saving: 2%

5. Anti-condensation spray: Energy saving: 1-2%

6. Optimise compressor set points: Energy saving: 15%

7. Ensure efficient operation of condensers and evaporators: Energy saving: 5-7%

8. Optimise evaporator set points: Energy saving 2% per ºC

Source: Nitra (2015)

References

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- Berner (2013) “Air Curtains: a Proven Alternative to Vestibule Design”

- Carbon Trust (2015) ”Refrigeration systems - Guide to key energy saving opportunities”.

- Cold Chain (2014) ”Minimizing Infiltration Into Refrigerated Spaces”. Available at: http://www.coldchainllc.com/wp-content/uploads/2013/02/Minimizing-Infiltration-into-refrigerated-spaces.pdf

- ICE-E (2014) ”ICE-E case study 4 Door protection”.

- ICE-E (2014b) “Loading and operation of cold rooms”

- Nitra (2015) “Chilling energy costs”.

- Savenergi (2014) ”-26°C Cold Store Trial – LED Hi-Bay Lights”.

- The ohio state university (2014) ”Using off-peak power rates to reduce refrigeration costs”.

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For more information contact CT-technologies via

www.ct-technologies.dk