Presentazione dell'Ing. Paul de Larminat (Johnson Controls) al XVI Convegno Europeo il 12 giugno 2015 - 2a sessione

1. Latest Technologies in Refrigeration and Air Conditioning - XVI European Conference Milano, 12th - 13th June 2015
Life Cycle Cost and Climate Performance:
Methodology for Techno-Economic Analysis
Paul de Larminat – Johnson Controls

2. Latest Technologies in Refrigeration and Air Conditioning - XVI European Conference Milano, 12th - 13th June 2015
Choice of the fluid vs. cycle efficiency
High critical temperature means
High Cycle Efficiency,
…and also low pressure,
and high volumetric flow
 Larger compressor.
When changing fluid at similar pressure level and with same
compressor technology, expect no change in efficiency.

3. Latest Technologies in Refrigeration and Air Conditioning - XVI European Conference Milano, 12th - 13th June 2015
What else can improve efficiency ?
Economized cycle
Liquid subcooling
VSD
Higher efficiency motors
Larger heat exchangers…
Within a given platform, size of heat exchangers provides
fine tuning of the trade-off between cost and efficiency.
Odrer of magnitude: 2% higher cost  1% higher efficiency.
Besides a fluid with better cycle efficiency,
there are other design options to improve efficiency, e.g:

4. Latest Technologies in Refrigeration and Air Conditioning - XVI European Conference Milano, 12th - 13th June 2015
Chillers: base line
and possible lower GWP options
State of the art base line is optimized, mature technology.
Additional constraints for lower GWP
can be expected to add to the cost.
Typical cooling Capacity (kW)
400 1000
Priceandefficiency
410A
Scroll
134A
Screw
134a or
Low Pressure
Centrifugal
Scrolls 410A --> R32 ?...
Screws 134a --> 1234ze ; NH3 ?...
Centrifugals 134a --> 1234ze ; 1233zd ?...
Possible replacement options

5. Latest Technologies in Refrigeration and Air Conditioning - XVI European Conference Milano, 12th - 13th June 2015
Carbon Foot Print of a Chiller
« Indirect » emissions (power generation) are about 90 to 99% of total.
« Direct » emissions are only a few percent of total equivelent CO2.

6. Latest Technologies in Refrigeration and Air Conditioning - XVI European Conference Milano, 12th - 13th June 2015
LCCP is close to TEWI
• LCCP (=Life Cycle Climate Performance) analyses overall emissions
of a product “from cradle to grave”.
• TEWI (=Total Equivalent Warming Impact) evaluates overall
emissions from commissioning to end of life.
• Both are very close.
Takes into account:
GWP of refrigerant
Leakage losses (L)
Recovery losses (αrecovery)
Life time (n)
Refrigerant charge (m)
Annual energy consumption (Eannual)
CO2 emissions of electricity (β) in kg/kWh

7. Latest Technologies in Refrigeration and Air Conditioning - XVI European Conference Milano, 12th - 13th June 2015
Lower eq-CO2 emissions have a cost.
Where to best invest this money ?
In lower GWP fluids ?
Generally higher price of fluids
And (or) cost of safety measures
…or in enhancing « conventional »
technologies for better efficiency ?
Where is the best compromise
between Life Cycle Cost and LCCP ?

8. Latest Technologies in Refrigeration and Air Conditioning - XVI European Conference Milano, 12th - 13th June 2015
Calculation Principle
Compare at equal capacity.
Start from base line  cost and efficiency (SEER).
From base line, estimate % efficiency improvement per 1% cost increase.
Estimate cost difference if lower GWP fluid.
If enhanced base line & same cost increase, determine efficiency improvement.
Make classical TEWI calculation in both options.
Compare, for energy efficiency and TEWI

9. Latest Technologies in Refrigeration and Air Conditioning - XVI European Conference Milano, 12th - 13th June 2015
Lower GWP system Enhanced "Conventional"
Life time Years 20
Cost increase % 6 6
Delta Efficiency/Delta cost % Eff / % Cost 0.5
Multiplier on efficiency 1.03
Indirect emissions
DesignCooling capacity kW 100 100
Maximum annual cooling MWh/yr 876 876
Multiplier on cooling energy 0.6 0.6
Actual annual cooling energy MWh/yr 526 526
SEER 5.0 5.2
Annual Energy consumption MWh/year 105 102
Carbon foot print of electricity T CO2/MWh 0.6 0.6
Total indirect emissions / Life T-Eq CO2 1261 1225
Direct emissions Very Very Very Very
Leak /EOL losses profile Low high Low high
Leak rate %/yr 0.5 2 4 10 30
EOL recovery % 95 80 60 30 0
Leaks/life time % 10 40 80 200 600
Total lost charge/life time % 15 60 120 270 700
Refrigerant charge kg/kW 0.28 0.28
Total lost charge/life time kg 4.2 16.8 33.6 75.6 196 4.2 16.8 33.6 75.6 196
GWP 10 1430
Direct emissions / Life time T-Eq CO2 0.04 0.2 0.3 0.8 2.0 6.01 24.0 48 108 280
Total Eq CO2emissions T-Eq CO2 1261 1262 1262 1262 1263 1231 1249 1273 1333 1505
Direct/total emissions % 0.0 0.0 0.0 0.1 0.2 0.5 1.9 3.8 8.1 18.6
Difference in total emissions % -2.4 -1.0 0.9 5.6 19.1
Difference in energy consumption % -3.00
HighLow Med. High Low Med.
Typical « generic » calculation

10. Latest Technologies in Refrigeration and Air Conditioning - XVI European Conference Milano, 12th - 13th June 2015
Example: large water cooled chiller
Range of input data
Climate
Low Med. High Med. High
Multiplier on Cooling Energy 0.2 0.4 0.9 0.6 0.9
SEER
Temperate Warm
9 8
Low Med. High
Life time Years 10 20 /
Cost increase % 4 6 8
Delta-Efficiency / Delta-cost % / % 0.3 0.5 0.7
Carbon footprint of electricity kgCO2/kWh 0.5 0.6 0.8
Annual leak rate % / yr 0.5 2 4
EOL (End Of Life) recovery % 95 80 60
For Chillers Low Medium High

11. Latest Technologies in Refrigeration and Air Conditioning - XVI European Conference Milano, 12th - 13th June 2015
Example: large water cooled chiller (2)
• Leaks are low (0.5 to 4%)
• Time in operation is highly variable. Depends on climate and on
application (A/C or process).
Climate
ColumnN° 1 2 3 4 5 6 7 8 9 10 11 12 13
Life time 20 20 10 20 20 20 20 20 20 20 20 20 20
Cost increase 6 6 6 6 6 6 6 4 8 6 6 6 6
Delta Efficiency/Delta cost 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.3 0.7 0.5 0.5
Multiplier on cooling energy 0.2 0.2 0.2 0.2 0.4 0.9 0.6 0.9 0.9 0.9 0.9 0.9 0.9
SEER 9 9 9 9 9 9 8 8 8 8 8 8 8
Carbon foot print of electricity 0.5 0.6 0.6 0.7 0.6 0.6 0.7 0.6 0.6 0.6 0.6 0.8 0.5
Difference energyconsumption % -3 -3 -3 -3 -3 -3 -3 -2 -4 -2 -4 -3.0 -3
Difference CO2 emissions (%)
VL 0.5 0.5 -0 0.5 -1 -1.6 -2.3 -2.3 -1.5 -3.3 -1 -3.5 -2.5 -2.2
Leak rate (%): M 2 11 7.3 11 5.9 2.2 -0.6 -0.3 0.1 -1.8 0.3 -2.0 -1.4 -0.2
VeryLow / Medium / high H 4 24 18 24 15 7.3 1.6 2.3 2.1 0.2 2.3 0.0 0.1 2.5
Temperate Warm

12. Latest Technologies in Refrigeration and Air Conditioning - XVI European Conference Milano, 12th - 13th June 2015
Sample of results
-4
-2
0
2
4
6
Low Medium High
DifferenceCO2emissions% Leak Rate
Difference in CO2 emissions vs Leak Rate
1 2 3 4 5 6
Life time Years 20
Cost increase % 6
Δη / Δcost %η / %cost 0.5
Common input data
Energy
Multiplier
Low 0.2
Medium 0.4
High 0.9
Medium 0.6
High 0.9
High 0.9 0.8
Climate SEER Usage KgCO2/kWh
Variable input data
0.6
Temperate
Warm
9
8

13. Latest Technologies in Refrigeration and Air Conditioning - XVI European Conference Milano, 12th - 13th June 2015
Conclusions
In this specific example of large water cooled chillers, and per the assumptions taken:
-The energy consumption of the « enhanced conventional solution » is 3% better than the
« low-GWP » option in all climates.
-For LCCP, the « enhanced conventional » generally has lower overall eq-CO2 emissions in
warm climate.
-In temperate climates, the result on LCCP depends on the usage:
- The low GWP solution is better for low usage (like A/C), unless leaks are very low.
- The « enhanced conventional » is better for intense use (like process cooling).
This example illustrates the interest of LCC / LCCP analysis, vs. focus on GWP only.
Still a lot to improve, but this kind of analysis is needed to identify really
sustainable solutions.
Energy Efficiency is a major issue on its own.

14. Latest Technologies in Refrigeration and Air Conditioning - XVI European Conference Milano, 12th - 13th June 2015
Thank you for your attention !
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