IEA ECES and IEA SHC joint workshop» - Solar Heating and Cooling and Energy Storage«November 8, 2011, University Rosenheim, Germany Life Cycle Assessment (LCA) of solar cooling systems Marco Beccali Dipartimento dell'energia - Università di Palermo, Italy
Development of renewable energy technologies (RETs) is important for reducing fossil fuels consumption while contributing to climate change mitigation. However, RETs cannot be considered totally clean because they have energy and environmental impacts that cannot be neglected during their life cycle. LCA of solar cooling systems Slide 2
The LCA approach takes into account the environmental impacts related to the entire life-cycle of a product. LCA can be used to investigate new technologies and can help decision makers to evaluate energy and environmental advantages of a certain technology within a specific climate. LCA of solar cooling systems Slide 3
1 Dipartimento dell'energia - Università di Palermo, Italy 2 University of Applied Sciences, Western Switzerland (HES-SO), School of Business and Engineering Vaud (HEIG-VD), Switzerland LCA of solar cooling systems Slide 4
Life Cycle Analysis of Solar Cooling systems Objectives Development of a LCA approach to Solar Cooling systems Organisation of information related to systems, components and materials Results: Methodology Report (Definition of methods for LCA, boundaries, Functional Units, Impacts Indicators, Cut-off Rules, Data-bases, etc) Case Studies Data Base: collection of data from literature (mainly for conventional systems development of original LCA of Solar Cooling Systems LCA of solar cooling systems Slide 5
FINAL REPORT SUMMARY 1. Introduction 2. Methodology: LCA for innovative heating and cooling systems 3. LCA Case Studies 3.1 Solar Cooling systems with Ad, Ab, VC chillers 3.1.1 Definition of case studies 3.1.2 Air to water vapor compression chiller and gas boiler 3.1.3 Simulation of configurations with hot and cold backup 3.1.4 Simulation results 3.1.5 Absorption chiller 3.1.6 Adsorption chiller 3.2. Solar DEC vs Conventional AHU 4. Conclusions 5. Bibliography 6. Annex LCA of solar cooling systems Slide 6
CASE STUDY: SORPTION MACHINES Four basic systems have been analysed in two locations: - ABsorption machine (12 kw) and 35 m 2 evacuated tubes with hot-back-up - ABsorption machine (12 kw) and 35 m 2 evacuated tubes with cold-back-up - ADsorption machine (8 kw) and 25 m 2 flat plate collectors with hot-back-up - ADsorption machine (8 kw) and 25 m 2 flat plate collectors with cold-back-up All the systems have an auxiliar boiler for the heating season. Total number of investigated combinations systems/load: 8 LCA of solar cooling systems Slide 7
For AD/ABS configurations with hot back-up Scheme with ADsorption Chiller Scheme with ABsorption Chiller For AD/ABS configurations with hot back-up Scheme of Reference System LCA of solar cooling systems Slide 8
Description of the case studies For all the systems hourly and monthly load profiles have been calculated LCA of solar cooling systems Slide 9
LCA ADSORPTION 8 kw ZURICH - PALERMO 25 m 2 flat plate collectors Adsorption machine 8 kw SORTECH Type 290-Sortech ACS08-2010 Type Author: Bjòrn Nienborg Fraunhofer ISE 1.3 m 3 hot storage Hot back up gas boiler 20 kw LCA of solar cooling systems Slide 10
LCA ABSORPTION 12 kw ZURICH - PALERMO Absorption machine 12 kw PINK Type 209 Version 2.0 Type Author: Jochen Döll Fraunhofer ISE 35 m 2 evacuated tubes 2 m 3 hot storage Hot back up gas boiler 20 kw LCA of solar cooling systems Slide 11
SIMULATION ADSORPTION 8 kw Annual Primary Energy Saving (%) Annual Primary Energy Saving (MWh) LCA of solar cooling systems Slide 12
SIMULATION ADSORPTION 8 kw Total Annual Primary Energy Saving (Cooling + Heating) MWh LCA of solar cooling systems Slide 13
SIMULATION ABSORPTION 12 kw Annual Primary Energy Saving (%) Annual Primary Energy Saving (MWh) LCA of solar cooling systems Slide 14
SIMULATION ABSORPTION 12 kw Total Annual Primary Energy Saving (Cooling + Heating) MWh LCA of solar cooling systems Slide 15
LCA of solar cooling systems Slide 16
The analysis of the other phases of the systems life has been carried out using the LCA methodology (ISO 14040 series) Softwares: SimaPro, Ecobat, Environmental database: Ecoinvent Assessment methods: EPD 2008 and Cumulative Energy Demand LCA of solar cooling systems Slide 17
Three Functional Units have been investigated: the solar cooling plant with absorption or adsorption chiller kw of cooling kwh of cooling + heating energy produced by plant LCA of solar cooling systems Slide 18
Investigated phases of the life : production of the main system components use of the system end-of-life of the main system components. Impacts related to transportations and maintainance have not been taken into account LCA have been applied also for two conventional systems able to meet the H/C load in the two locations LCA of solar cooling systems Slide 19
The eco-profiles (balances of energy and resources of the product) of: solar collectors, gas boiler, heat storage, vapor compression chiller, pumps and piping, have been referred to Ecoinvent database The eco-profiles of: absorption chiller, adsorption chiller and the cooling tower have been assessed by the authors starting from data collected in field in co-operation with manufactures The energetic and environmental impacts related to the electricity use are referred to the Italian and Swiss energy mix. LCA of solar cooling systems Slide 20
Example: Absorption Chiller System with Hot backup Components Non-Renewable Energy Requirement (MJ-eq) Global Energy Requirement (MJ-eq) Global Warming Potential (kg CO 2eq ) Absorption chiller 23,457 28,058 1,757 Solar collectors 54,987 59,415 3,437 Heat storage 13,622 15,209 852 Production of Cooling Tower/Heat Rejection 2,902 2,972 154 plant components Gas boiler 1,726 1,853 103 Glycol (only for plant in Zurich) 2,039 2,100 103 Piping+insulation 7,961 8,399 510 Pumps 1,017 1,095 66 Use phase Cooling 258,719 279,604 16,766 Palermo Heating 59,109 60,425 3,556 Use phase Zurich Cooling 166,883 193,422 3,431 Heating 1,154,443 1,161,699 66,939 Absorption chiller 3 3 13 Solar collectors 398 419 315 Heat storage 21 21 13 End-of-life Cooling Tower/Heat Rejection 0 0 0 Gas boiler 16 17 5 Piping+insulation 12 13 92 Glycol (only for plant in Zurich) 459 461 39 Pumps 3 3 1 Total Palermo 423,954 457,506 27,637 Total Zurich 1,429,949 1,475,160 77,828 LCA of solar cooling systems Slide 21
Example: Adsorption Chiller System with Hot backup Components Non-Renewable Energy Requirement (MJ-eq) Global Energy Requirement (MJ-eq) Global Warming Potential (kg CO 2eq ) Adsorption chiller 22,202 24,187 1,380 Solar collectors 40,723 46,604 2,385 Heat storage 12,142 13,690 735 Production of Cooling Tower/Heat Rejection 12,680 14,348 770 plant components Gas boiler 1,726 1,853 103 Glycol (only for plant in Zurich) 1,576 1,636 64 Piping+insulation 7,821 8,256 412 Pumps 1,017 1,095 66 Use phase Cooling 187,295 198,483 11,825 Palermo Heating 52,002 53,335 3,142 Use phase Zurigo Cooling 120,033 128,418 5,090 Heating 836,423 842,404 48,321 Adsorption chiller 12 12 21 Solar collectors 200 215 247 Heat storage 18 19 11 End-of-life Cooling Tower/Heat Rejection 9 9 105 Gas boiler 16 17 5 Glycol (only for plant in Zurich) 459 461 39 Piping+insulation 12 13 92 Pumps 3 3 1 Total Palermo 337,860 362,7140 21,299 Total Zurigo 1,057,054 1,083,240 59,846 LCA of solar cooling systems Slide 22
Absorption Chiller System: Hot backup Impact per life-cycle step. Palermo Zurich LCA of solar cooling systems Slide 23
Absorption Chiller System: Hot backup Impacts for the production Palermo Zurich LCA of solar cooling systems Slide 24
Absorption Chiller with Hot backup: Impacts per component (%) Absorption chiller CED Absorption chiller GWP LCA of solar cooling systems Slide 25
Absorption Chiller System: Hot backup Result for the Functional Units Palermo NRE (MJ-eq) GER (MJ-eq) GWP (kg CO 2eq ) F.U. 1 solar cooling plant F.U. 1 kw of chiller power F.U. 1 kwh of produced energy Zurich Production phase 105,673 117,000 6,878 Use phase 317,828 340,029 20,322 End-of-life phase 453 477 438 Production phase 8,806 9,750 573 Use phase 26,486 28,336 1,693 End-of-life phase 38 40 36 Production phase 0.55 0.61 0.04 Use phase 1.66 1.78 0.11 End-of-life phase 0.002 0.002 0.002 NRE (MJ-eq) GER (MJ-eq) GWP (kg CO 2eq ) F.U. 1 solar cooling plant F.U. 1 kw of power F.U. 1 kwh of produced energy Production phase 107,712 119,101 6,981 Use phase 1,321,326 1,355,121 70,370 End-of-life phase 912 938 477 Production phase 8,976 9,925 582 Use phase 110,110 112,927 5,864 End-of-life phase 76 78 40 Production phase 0.28 0.31 0.02 Use phase 3.43 3.52 0.18 End-of-life phase 0.002 0.002 0.001 LCA of solar cooling systems Slide 26
Adsorption Chiller System: Hot backup Result for the Functional Units Palermo F.U. 1 solar cooling plant F.U. 1 kw of chiller power F.U. 1 kwh of produced energy Zurich F.U. 1 solar cooling plant F.U. 1 kw of chiller power F.U. 1 kwh of produced energy NRE (MJ-eq) GER (MJ-eq) GWP (kg CO 2eq ) Production phase 98293 110033 5851 Use phase 239297 251819 14967 End-of-life phase 270 288 481 Production phase 12287 13754 731 Use phase 29912 31477 1871 End-of-life phase 34 36 60 Production phase 0.86 0.96 0.05 Use phase 2.10 2.21 0.13 End-of-life phase 0.002 0.003 0.004 NRE (MJ-eq) GER (MJ-eq) GWP (kg CO 2eq ) Production phase 99869 111669 5915 Use phase 956456 970822 53411 End-of-life phase 729 749 520 Production phase 12484 13959 739 Use phase 119557 121353 6676 End-of-life phase 91 94 65 Production phase 0.39 0.43 0.02 Use phase 3.69 3.74 0.21 End-of-life phase 0.003 0.003 0.002 LCA of solar cooling systems Slide 27
ABS vs Conv: Impact per different phases 2500000 Zurich GER [MJ] 2500000 Palermo GER [MJ] End-of-life phase Use phase Production phase End-of-life phase Use phase Production phase 2000000 2000000 1500000 1500000 1000000 1954272 1000000 1345336 1355121 500000 500000 845485 346860 340029 0 14357 0,7 % 131605 8,9 % 119101 8,1 % Conv Cold Hot 0 14357 1,7% 129505 27,2% 117000 25,6 % Conv 1 Cold 2 Hot 3 LCA of solar cooling systems Slide 28
ADS vs Conv: Impact per different phases 1400000 1200000 1000000 800000 Zurich - GER [MJ] End-of-life phase Use phase Production phase Palermo - GER [MJ] End-of-life phase Use phase Production phase 1400000 1200000 1000000 800000 600000 1237172 949459 970822 600000 400000 200000 0 400000 200000 499882 216320 251819 14357 1,1 % 124174 11,5 % 111669 10,3 % 0 14357 2,8 % 122538 36,1 % 110033 30,4% Conv Cold Hot Conv Cold Hot LCA of solar cooling systems Slide 29
Energy payback time Energy Payback Time (E PT ): can be defined as the time necessary for a plant to save as much energy (valued as primary) as that consumed during all the life-cycle phases of system itself: GER Innovative = Primary energy consumed during LCA phases [MJ]; GER reference = Primary energy consumed during LCA phases of reference system [MJ]; E year = Net Yearly primary energy saving due to the use of the innovative system [MJ per year]. Slide 30
PAY BACK INDEXES Energy Payback Time (E PT ): the time necessary for a plant to save as much energy (valued as primary) as that consumed during all the life-cycle phases Emission Payback Time (EM PT ): the time necessary for a plant to save as much greenhouse gas emissions (valued as CO2 eq) as that emitted during all the lifecycle phases Energy Return Ratio (ERR): how many times the energy savings on the lifetime of the installation is relative to the energy needed to manufacture the innovative system LCA of solar cooling systems Slide 31
Results EPT EPT ranges from 4.4 to 9.3 years. The systems which requires less years to give back the energy needed for its construction, operation and disposal are the one using ABS chillers. - for a given system the colder the climate the lower the energy payback time - for a given climate and chiller typology: the «hot back-up» is slightly better than the «cold backup» (with some exception) LCA of solar cooling systems Slide 32
Results EMPT ranges from 3,9 to 10,6 years. - for a given climate and back-up typology: systems with ABS chillers performs better than ones with ADS chillers - for system with ABS, the colder the climate the lower the emission payback (slightly) - for a given system with ADS the colder the climate the higher the emission payback - for a given climate and chiller typology: the «hot back-up» is better than the «cold back-up» LCA of solar cooling systems Slide 33
Conclusions It is worth noting that the results obtained show good performances of almost all the configurations from the environmental point of view. They can be used to show the net environmental benefits related to SHC systems despite the larger amount of energy and emissions related to their construction LCA of solar cooling systems Slide 34
Payback Indexes In order to appreciate the influence of some performance parameters of the systems a sensitivity analysis on Ept has been produced. The parameters which have been varied from the design conditions are: equivalent hours of cooling operation (defined as the ratio between the cooling energy delivered and the nominal cooling power) equivalent hours of heating operation (defined as the ratio between the cooling energy delivered and the nominal cooling power) annual consumption of electricity for cooling (with the same amount of cooling energy delivered) annual consumption of gas for heating (with the same amount of heating energy delivered) Slide 35
Payback Indexes vs parameters (Absorption) EPT vs. parameters Slide 36
Payback Indexes vs parameters (Absorption) Very relevant influence for the coldest climate when hours are reduced from the design point. Very relevant influence for the hottest climate for reduction of operation hours in summer. Slide 37
Payback Indexes vs parameters (Absorption) Very small increase in electricity consumption can cause relevant changes in EPT in both the climates The highest influence of this parameter is observed for the installation in Zurich where the higher heating load is fulfilled. Slide 38
Conclusions The application of LCA approach to solar cooling system is brand new and the results are very interesting Once again, it is demonstrated that good design and operation conditions are necessary to allow good energy and environmental performances Installations with poor energy saving could have a negative balance of emissions during all the life cycle because of emissions related to the production phase are not balanced by the ones avoided during the use phase Impacts related to construction phase could be lowered by introducing new materials Slide 39
Thank you for the attention marco.beccali@unipa.it LCA of solar cooling systems