Chillers are an important component of the heating ventilation, and air conditioning industry which is one of the largest energy consuming sectors. Magnetic bearing systems have been adopted in the chiller industry to improve compressor efficiency. A life cycle assessment (LCA) of greenhouse gas emissions of magnetic bearing chillers, with a particular focus on the manufacturing stage, has not previously been conducted. This study evaluated global warming potentials of two water chiller systems, an oil lubricated bearing system, and a magnetic bearing system, over their life cycle stages including raw material extraction, manufacturing, transportation, use, and the end of life. The standard ISO 14044 LCA framework was employed to assess the two 500-ton cooling capacity chillers from a US chiller manufacturing company. Uncertainty analysis was conducted on carbon emission factors from the research literature and sensitivity analysis was conducted on key variables including power mix emission factor, chiller efficiency, and transportation method. The results show that magnetic bearing systems perform better with respect to life cycle GHG emissions. For a general water chiller system life cycle, over 90% of the emissions result from electricity consumption during the use stage with the next largest emissions arising from material extraction and manufacturing. While the material use and manufacturing GHG emissions are similar in the two systems, due to its higher compressor efficiency the magnetic bearing system generates fewer GHG emissions in the use stage. Sensitivity analysis was conducted on electricity mix, non-standard part load value (NPLV), and transportation method. When the factor values were varied with 5% steps to ±25%, the chiller efficiency and power mix emission factors behaved in similar ways in improving life cycle GHG emissions. NPLV, however, becomes more challenging to improve despite the long history of research on compressor efficiency. This study not only provides analytical data at the product level as to how much GHG emissions can be reduced by improving compressor efficiency and incorporating clean energy, but also provides life cycle GHG inventory data for different end of life and transportation strategies.

中文翻译：

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磁轴承和油润滑轴承水冷式冷水机组的生命周期温室气体评估

冷水机是暖通空调的重要组成部分，而空调行业是最大的能源消耗行业之一。冷水机行业已采用磁轴承系统来提高压缩机效率。磁轴承冷水机温室气体排放的生命周期评估 (LCA)，特别关注制造阶段，以前从未进行过。本研究评估了两个冷水机组系统（油润滑轴承系统和磁力轴承系统）在其生命周期阶段（包括原材料提取、制造、运输、使用和寿命结束）的全球变暖潜力。使用标准 ISO 14044 LCA 框架来评估来自美国冷水机制造公司的两台 500 吨制冷量冷水机。对研究文献中的碳排放因子进行不确定性分析，对电力组合排放因子、冷水机组效率和运输方式等关键变量进行敏感性分析。结果表明，磁性轴承系统在生命周期温室气体排放方面表现更好。对于一般的冷水机系统生命周期，超过 90% 的排放来自使用阶段的电力消耗，其次最大的排放来自材料提取和制造。虽然两个系统的材料使用和制造温室气体排放相似，但由于其更高的压缩机效率，磁轴承系统在使用阶段产生的温室气体排放更少。对电力组合、非标准部分负荷值 (NPLV)、和运输方式。当因子值以 5% 的步长变化到 ±25% 时，冷水机组效率和动力组合排放因子在改善生命周期温室气体排放方面的表现相似。然而，尽管对压缩机效率的研究已有很长的历史，但 NPLV 的改进变得更具挑战性。本研究不仅提供了产品层面的分析数据，说明通过提高压缩机效率和采用清洁能源可以减少多少温室气体排放，还提供了不同生命周期结束和运输策略的生命周期温室气体清单数据。尽管对压缩机效率的研究历史悠久，但改进变得更具挑战性。本研究不仅提供了产品层面的分析数据，说明通过提高压缩机效率和采用清洁能源可以减少多少温室气体排放，还提供了不同生命周期结束和运输策略的生命周期温室气体清单数据。尽管对压缩机效率的研究历史悠久，但改进变得更具挑战性。本研究不仅提供了产品层面的分析数据，说明通过提高压缩机效率和采用清洁能源可以减少多少温室气体排放，还提供了不同生命周期结束和运输策略的生命周期温室气体清单数据。