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Cool Ideas for your Refrigeration System
Zaid Al-Chalabi, P.Eng
Energy Management Consultant
Dr. Constantin Pitis, P.Eng
Specialist Engineer
00 5% 10% 15% 20% 25% 30% 35% 40% 45% 50% 55% 60% 65% 70% 75%
of Refrigeration LOAD is Non-Productive
Up to
Varies based on facility type and operating conditions
Presentation Objectives
1. Understanding Refrigeration Systems
2. Benchmarking your Facility Energy Segregation based on Facility types
Equipment Segregation
Refrigeration Loads
Energy Usage Intensity (EUI)
New Concept: Benchmark Energy Factor (BEF)
3. Energy Efficiency Opportunities
Industrial Refrigeration in BC
Estimated Energy consumption for Cooling & Refrigeration
Systems ≈ 485 GWh/year or about 50,000 homes
Facility Types: Cold Storage, Distribution, Processing
Estimated Energy Savings Potential
≈ 75 GWh/year ≈ $4,500,000 per year
Extrapolated based on BC Hydro Conservation Potential Report (CPR) 2007
Vapor-Compression Cycle
Outdoor Fan
Compressor
Ambient conditions
Condenser Coils
Battery Charging
for forklifts
Conditioned Environment
Indoor Fan
Indoor Lighting
Evaporator Coils
High pressure high temp. vapor
Low pressure low temp. liquid + vapor
Low pressure low temp. vapor
High pressure high temp. liquid
Expansion Valve
High Pressure
Side
Low Pressure
Side
C
Underfloor Heating
(Freezers)
Cold Storage
Infiltration Load
Product Product
Product Heat Load
Insulated Walls
Access Doors
Waste Heat
Cold Air Warm Air
Refrigerant Line
Refrigeration Energy
Heat Load
Equipment Segregation
Refrigeration Energy
Compressor
Condenser + Fan motor
Evaporator + Fan motor
Special Refrigerated Processes
(i.e. cooling tunnels) – if applicable
Cold Storage Lighting
Expansion Valve (metering device)
Access Doors
Non-Refrigeration Energy
Office Space HVAC/Lighting
Dry Storage HVAC/Lighting
Non-refrigerated Processes
(if applicable)
Forklift Battery Chargers
Underfloor Heating
(freezers)
Other
Energy Segregation
Non-Refrigeration
Energy
Total Metered
Energy
Refrigeration
Energy
Product
Cooling
Non-Refrigeration Energy
varies based on Facility Type
(10…50%)
Essential
Energy
Wasted Energy
Wasted Energy can be reduced by
applying Energy Conservation
Measures
Minimum Energy Required
to meet refrigeration load
Total Metered
Energy
Based on internal pilot testing on sample site
Energy Segregation on Facility Types
Facility Type Refrigeration
Energy (%)
Non-Refrigeration
Energy (%)
1 Distribution Facility 60 40
2 Storage Warehouse 90 10
3 Processing + Storage 80 20
4 Refrigerated Processing +
Storage 65 35
Based on internal pilot testing on sample sites
Refrigeration Load for Distribution Facilities
Envelope/Infiltration (56…70%)
Product (14…20%)
Lighting (8…12%)
Evaporator Fan (8…12%)
Refrigeration
Energy
(Load)
Based on internal pilot testing on sample site
Product Load: Volume Vs Weight
𝑷𝒓𝒐𝒅𝒖𝒄𝒕 𝒄𝒐𝒐𝒍𝒊𝒏𝒈 𝒍𝒐𝒂𝒅 ≈ 𝑾𝒆𝒊𝒈𝒉𝒕 ∗ 𝑪 ∗ ∆𝑻
Fruit Cases Meat Cases
Volume = 1 m3
Weight = 300 kg C = 3.4 kJ/kg.C
ΔT = 3оF
Volume = 1 m3
Weight = 700 kg C = 3.6 kJ/kg.C
ΔT = 3оF
Heavier products costs more to cool!
Product load TWICE as
high
Energy Use Intensity (EUI)
Traditional approach in assessing facility performance: kWh per cubic foot
𝑬𝑼𝑰 =𝑻𝒐𝒕𝒂𝒍 𝑴𝒆𝒕𝒆𝒓𝒆𝒅 𝑬𝒏𝒆𝒓𝒈𝒚
𝑺𝒑𝒂𝒄𝒆 𝑽𝒐𝒍𝒖𝒎𝒆
EUI does NOT accurately assess your facility’s performance because:
Assumes Total Metered Energy = Refrigeration Energy
Does not take into account Independent Variable Parameters:
Facility Type and Layout
Product Type and Quantity (kg)
Product and Space Temperatures
= 𝑅𝑒𝑓𝑟𝑖𝑔. 𝐸𝑛𝑒𝑟𝑔𝑦 + 𝑁𝑜𝑛. 𝑅𝑒𝑓𝑟𝑖𝑔. 𝐸𝑛𝑒𝑟𝑔𝑦
Varies based on Facility Type
(10%…50%)
Benchmark Energy Factor (BEF)
New approach in assessing facility performance: Unit-less Value
𝑩𝑬𝑭 =𝑹𝒆𝒇𝒓𝒊𝒈𝒆𝒓𝒂𝒕𝒊𝒐𝒏 𝑬𝒏𝒆𝒓𝒈𝒚
𝑬𝒔𝒔𝒆𝒏𝒕𝒊𝒂𝒍 𝑬𝒏𝒆𝒓𝒈𝒚
Example
Site No.* 𝑩𝑬𝑭 =
𝑹𝒆𝒇𝒓𝒊𝒈. 𝑬
𝑬𝒔𝒔𝒆𝒏𝒕𝒊𝒂𝒍 𝑬. 𝑬𝑼𝑰 =
𝑻𝒐𝒕𝒂𝒍 𝑬.
𝑽𝒐𝒍𝒖𝒎𝒆
1 4.8 (Poor Efficiency) 0.46 (Good Efficiency ?)
2 3.5 (Good Efficiency ) 0.85 (Poor Efficiency ?)
BEF method takes into account Independent Variable Parameters such as:
Facility Type
Product Type and Weight
Facility Layout and Location
Operating hours
Space and Product Temperatures
= 𝑇𝑜𝑡𝑎𝑙. 𝑀𝑒𝑡𝑒𝑟𝑒𝑑. 𝐸𝑛𝑒𝑟𝑔𝑦 − 𝑁𝑜𝑛. 𝑅𝑒𝑓𝑟𝑖𝑔. 𝐸𝑛𝑒𝑟𝑔𝑦
Minimum Energy required to meet refrigeration load
*Based on internal pilot testing for sample sites
Monitoring Energetic Performance
Energy Conservation Measure: VFDs on Evaporator Fan Motors
Energy Savings = 206,000 kWh (4 month period)
0
100,000
200,000
300,000
400,000
500,000
600,000
700,000
May June July August September October November December January February March April
kW
h
Month
Wasted Energy
After (2014)
Essential Energy
Before (2013)
Based on internal pilot testing on sample site
ECM implemented
Refrigeration Energy
Efficient Measures
Energy Efficient Measure Potential System Energy Savings
Cost to Implement
High Speed Doors 2-10% Low
High Efficiency Lighting and Controls 5-20% Medium
Variable Frequency Drives on Compressor 10-20% High
Variable Frequency Drives (or EC Motors) on Evaporator/Condenser Fans
2-5% Low-Medium
Central Control System 5-15% Low-Medium
Floating head pressure control 3-12% Low
Sources: (1) Historical Power smart Projects. (2) Wisconsin State Utilities
Potential Refrigeration Energy Savings: up to 45%
Non-Refrigeration Energy
Efficient Measures
Energy Efficient Measures Potential Energy
Savings Cost to
Implement
Potential Non-Refrigeration Energy Savings: up to 35%
Source: (1) Historical Power smart Projects. (2) California Utility Company
Heat Recovery for Underfloor Heating (freezers)
5-10% Low-Medium (new plant)
Forklift Battery Chargers 5-15% Low-Medium
Dry Storage/Other Areas HVAC Upgrades 5-15% Medium
Dry Storage/Other Areas Lighting Upgrade 5-10% Medium
Energy Efficiency Benefits
Energy efficiency can deliver a range of savings, such as:
• Reduced energy costs
• Reduced operation and maintenance costs
• Improved system reliability
• Improved safety
• Increased productivity
• Matching of refrigeration load and equipment capacity
• a better working environment
Summary of Cool Ideas
1. Total Metered Energy = Refrig. Energy + Non.Refrig. Energy
2. Non-Refrigeration Energy varies based on Facility Type
3. Essential Energy = Minimum energy required to meet Refrig. load
4. Product weight is equally important to know as type and quantity
5. Energy Use Intensity (EUI) is not an accurate method to assess facility performance
6. New Concept: Benchmark Energy Factor (BEF) takes into account independent variable parameters
Thank You!
Email: [email protected]
Zaid Al-Chalabi, P.Eng
#psforum15
Email: [email protected]
Dr. Constantin Pitis, P.Eng
