Abstract

District heating and cooling systems are designed and optimized to respond to the latest challenges of reducing energy demands while fulfilling comfort standards. Thermal energy storage (TES) with phase change materials can be employed to reduce the energy demands of buildings. This study considers a residential district located in Spain, where a general framework has been established to identify optimal combinations of energy conversion, delivery technologies, and operating rules. The Life Cycle Assessment (LCA) methodology was implemented within a mathematical model, and the objective function considered the minimization of environmental loads. Two environmental impact assessment methods were applied within the LCA methodology: IPCC 2013 GWP 100y and ReCiPe. Four optimal configurations were considered: a reference system (gas boiler and split-type air conditioners) and then three TES-based systems: one sensible (STES, water) and two latent (LTES1—paraffin emulsion and LTES2—sodium acetate trihydrate). Hourly environmental loads associated with electricity imports from the national grid were available. The conventional energy system always presented the worst performance from an environmental viewpoint, being penalized by the high consumption of natural gas. Regarding carbon emissions, LTES1 showed the lowest emissions, followed by STES and LTES2. Reductions in energy demands compensated the impact of paraffin, and results of STES are strongly dependent on tank design. However, considering the ReCiPe method, STES presented the lowest loads, followed by LTES1 and LTES2. Overall impacts of LTES1 with paraffin are higher than STES with water, mainly due to the paraffin and the high volume required.

Graphic abstract

中文翻译：

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通过结合热能存储和生命周期评估来可持续增强区域供热和制冷配置

摘要

设计和优化了区域供热和制冷系统，以应对在满足舒适性标准的同时减少能源需求的最新挑战。可以采用具有相变材料的热能存储（TES）来减少建筑物的能源需求。这项研究考虑了西班牙的一个居民区，该区已建立了一个通用框架来确定能源转换，输送技术和运行规则的最佳组合。生命周期评估（LCA）方法是在数学模型内实施的，目标函数考虑了环境负荷的最小化。LCA方法中应用了两种环境影响评估方法：IPCC 2013 GWP 100y和ReCiPe。考虑了四个最佳配置：参考系统（燃气锅炉和分体式空调），然后是三个基于TES的系统：一个显性（STES，水）和两个潜在性（LTES1-石蜡乳液和LTES2-三水合乙酸钠）。提供了与从国家电网进口的电力相关的每小时环境负荷。从环境的角度来看，传统的能源系统总是表现出最差的性能，因为天然气消耗量大。关于碳排放，LTES1排放最低，其次是STES和LTES2。能源需求的减少抵消了石蜡的影响，STES的结果在很大程度上取决于储罐的设计。但是，考虑到ReCiPe方法，STES的负载最低，其次是LTES1和LTES2。LTES1含石蜡的总体影响高于STES含水，

图形摘要