Editing IPCC:AR6/WGIII/Chapter-9 (section)

=== 9.4.4 Case Studies ===

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==== 9.4.4.1 Warehouses ====

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Warehouses are major contributors to the rise of greenhouse gas emissions in supply chains ( [[#Bartolini--2019|Bartolini et al. 2019]] ). The expanding e-commerce sector and the growing demand for mass customisation have even led to an increasing need for warehouse space and buildings, particularly for serving the uninterrupted customer demand in the business-to-consumer market. Although warehouses are not specifically designed to provide their inhabitants with comfort because they are mainly unoccupied, the impact of their activities in the global GHG emissions is remarkable. Warehousing activities contribute roughly 11% of the total GHG emissions generated by the logistics sector across the world. Following this global trend, increasing attention to green and sustainable warehousing processes has led to many new research results regarding management concepts, technologies, and equipment to reduce warehouses carbon footprint, that is, the total emissions of GHG in carbon equivalents directly caused by warehouses activities.

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==== 9.4.4.2 Historical and Heritage Buildings ====

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Historical buildings, defined as those built before 1945, are usually low-performance buildings by definition from the space heating point of view and represent almost 30–40% of the whole building stock in European countries ( [[#Cabeza--2018a|Cabeza et al. 2018a]] ). Historical buildings often contribute to townscape character, they create the urban spaces that are enjoyed by residents and attract tourist visitors. They may be protected by law from alteration not only limited to their visual appearance preservation, but also concerning materials and construction techniques to be integrated into original architectures. On the other hand, a heritage building is a historical building which, for their immense value, is subject to legal preservation. The integration of renewable energy systems in such buildings is more challenging than in other buildings. In the review carried out by [[#Cabeza--2018a|Cabeza et al. (2018a)]] different case studies are presented and discussed, where heat pumps, solar energy and geothermal energy systems are integrated in such buildings, after energy efficiency is considered.

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==== 9.4.4.3 Positive Energy or Energy Plus Buildings ====

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The integration of energy generation on-site means further contribution of buildings towards decarbonisation ( [[#Ürge-Vorsatz--2020|Ürge-Vorsatz et al. 2020]] ). Integration of renewables in buildings should always come after maximising the reduction in the demand for energy services through sufficiency measures and maximising efficiency improvement to reduce energy consumption, but the inclusion of energy generation would mean a step forward to distributed energy systems with high contribution from buildings, becoming prosumers ( [[#Sánchez%20Ramos--2019|Sánchez Ramos et al. 2019]] ). Decrease price of technologies such as photovoltaic (PV) and the integration of energy storage (de Gracia and Cabeza 2015) are essential to achieve this objective. Other technologies that could be used are photovoltaic/thermal ( [[#Sultan--2018|Sultan and Ervina Efzan 2018]] ), solar/biomass hybrid systems ( [[#Zhang--2020b|Zhang et al. 2020b]] ), solar thermoelectric ( [[#Sarbu--2018|Sarbu and Dorca 2018]] ), solar powered sorption systems for cooling ( [[#Shirazi--2018|Shirazi et al. 2018]] ), and on-site renewables with battery storage ( [[#Liu--2021|Liu et al. 2021]] ).

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==== 9.4.4.4 District Energy Networks ====

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District heating networks have evolved from systems where heat was produced by coal or waste and storage was in the form of steam, to much higher energy efficiency networks with water or glycol as the energy carrier and fuelled by a wide range of renewable and low carbon fuels. Common low carbon fuels for district energy systems include biomass, other renewables (i.e., geothermal, PV, and large solar thermal), industry surplus heat or power-to-heat concepts, and heat storage including seasonal heat storage ( [[#Lund--2018|Lund et al. 2018]] ). District energy infrastructure opens opportunities for integration of several heat and power sources and is ‘future proof’ in the sense that the energy source can easily be converted or upgraded in the future, with heat distributed through the existing district energy network. Latest developments include the inclusion of smart control and AI ( [[#Revesz--2020|Revesz et al. 2020]] ), and low temperature thermal energy districts. Authors show carbon emissions reduction up to 80% compared to the use of gas boilers.

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