Rate Load Life Cycle Assessment Method
Rate Load Life Cycle Assessment Method
- 주제(KDC) 539
- 주제(DDC) 628
- 발행기관 아주대학교
- 지도교수 이건모
- 발행년도 2007
- 학위수여년월 2007. 8
- 학위명 박사
- 학과 및 전공 일반대학원 환경공학과
- 본문언어 영어
초록/요약
ABSTRACT One of the deficiencies of the conventional Life Cycle Assessment (LCA) method is that it does not consider time explicitly. In addition, there are problems associated with the temporal boundary in the normalization step of LCA. The purpose of this research is to propose a new life cycle assessment method termed “rate load LCA method” that incorporated time dimension into the life cycle inventory analysis and thus life cycle impact assessment phases and rectifies the inconsistency problem in temporal boundary in the normalization step. Basic premise of the rate load LCA method is that same amount of load over a shorter time period would affect more seriously on the environmental than that over a longer time period. In this work, the manufacturing throughput time and the critical path time concept were used as parameters for consideration of time dimension in the inventory data collection step. Time duration of each life cycle stage was used in order to calculate both the inventory rate load and the characterized impact rate load. Next, the difference between the conventional (cumulative load) LCA method and the rate load LCA method was analyzed. A modified definition of normalized impact was made to solve inconsistency problem in the temporal boundary between the characterized impact and the normalization reference. In the case study, LCA data of a refrigerator were used to compare the cumulative load LCA method with the rate load LCA method. The considered impact categories in this case study were acidification and global warming. Comparison between the cumulative load LCA method and the rate load LCA method results in different pictures about the distribution of the environmental loads among different life cycle stages. This leads to identification of different significant issues of a product system. The time adjustment to the normalized impact calculation also eliminates inconsistency problem in the temporal boundary between the characterized impact and the normalization reference. In the case study, the significant issues of a refrigerator product system was the use stage if the cumulative load LCA method was used, and the manufacturing stage if the rate load LCA method was used. The different significant issues of the refrigerator from the two different LCA methods are the direct result of considering time duration in the inventory data collection step. Time consideration in the rate load LCA method indicated that the proposed method not only renders new perspective on the environmental impacts of a product system but also rectifies inconsistency in temporal dimension of the normalization step. Thus, it can be stated that the rate load LCA method is complementary to the cumulative load LCA method. Next, the carrying capacity concept can be considered into the rate load LCA method. The fractional depletion of carrying capacity was defined and the calculation procedure of the fractional depletion of carrying capacity was proposed. In the case study, the critical loads in ten areas of Korea were chosen in order to demonstrate the effect of critical load on the environmental impact caused by characterized impact rate load (CIRL). The fractional depletion of carrying capacity can provide new insight as to the nature of the resource consumption and environmental emissions of a product system by considering the carrying capacity in the area of interest.
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TABLE OF CONTENTS
Page
Abstract i
Table of Contents iii
Tables vi
Figures vii
1. INTRODUCTION 1
1.1 Introduction 1
1.2 Objective and Scope of Study 3
2. LITERATURE REVIEW 4
2.1 Introduction of LCA 4
2.2 Limitations of LCA 6
2.3 Characterization and Normalization Methodology of the Conventional LCA 8
2.3.1 Conventional LCA Method 9
2.3.2 EDIP Method 10
2.4 Time Consideration in LCA 12
2.4.1 The Time Frame of Goal
and Scope Definition 13
2.4.2 Time in Life Cycle Inventory
Analysis 14
2.4.3 The Time Frame of LCIA 21
2.4.4 Summary of Time
Consideration in LCA 23
2.5 Time Estimation Methods 26
2.5.1 Critical Path Method 26
2.5.2 Manufacturing Throughput
Time Concept 32
2.5.3 The Solid Waste Collection
Time 35
2.6 Carrying Capacity Concept 39
2.6.1 Introduction 39
2.6.2 RAINS Model in LCA 40
3. METHODOROGY 49
3.1 Life Cycle Stage 49
3.2 Cumulative Load LCA Method 51
3.2.1 Inventory Cumulative Load 51
3.2.2 Characterization and
Normalization Cumulative Load 52
3.3 Rate Load LCA Method 55
3.3.1 Inventory Rate Load 55
3.3.2 Characterization Rate Load 56
3.3.3 Time Estimation in the
Rate Load LCA Method 56
3.4 Refrigerator Case Study 63
3.5 Rate Load LCA Related to Carrying
Capacity Concept 65
3.5.1 Application of RAINS
model to the Rate Load LCA
Method 68
4. RESULTS AND DISSCUSION 72
4.1 Comparison between the Rate Load
LCA Method and the Cumulative Load
LCA Method 72
4.2 Relationship between Time and
the Rate Load 77
4.3 Normalization Problems 78
4.4 Rate Load LCA Case Study 82
4.5 RAINS Model Case Study 86
4.6 Fractional Depletion of Carrying Capacity 87
4.6.1 Definition of Fractional
Depletion of Carrying Capacity 87
4.6.2 Calculation Procedure 88
4.6.3 Acidification Case Study 91
4.6.4 Carbon Dioxide Case Study 78
5. CONCLUSION 97
REFERENCES 100
