Humidity’s impact on greenhouse gas emissions from air conditioning

Woods, Jason; James, Nelson; Kozubal, Eric; Bonnema, Eric; Brief, Kristin; Voeller, Liz; Rivest, Jessy B.

doi:10.1016/j.joule.2022.02.013

“…The importance of the latter is often overlooked. Globally, carbon emissions associated with removing humidity loads (latent cooling) are slightly larger than temperature loads (sensible cooling) (Woods et al., 2022). One reason for the energy, carbon, and financial cost of latent cooling is the thermodynamic inefficiency of their removal.…”

Section: Multidisciplinary Solutions To Address Urban Overheatingmentioning

confidence: 99%

“…Improved efficiency (and lower cost of operation, an important characteristic of equitable heat resilience) comes from separating sensible and latent cooling, which has the twin benefits of increasing the efficiency of both processes. In this approach, water vapor is removed with desiccants or pressure‐induced flows of water vapor across selectively permeable membranes (Claridge et al., 2019; Fix et al., 2021; Labban et al., 2017; Woods et al., 2022). Further separation of sensible and latent cooling can be achieved with radiant sensible cooling and latent cooling in a dedicated outdoor air system (DOAS), which provides limited sensible cooling to lower the temperature of the minimum airflow needed for indoor air quality (Ali et al., 2018; Fix et al., 2021; Labban et al., 2017).…”

Section: Multidisciplinary Solutions To Address Urban Overheatingmentioning

confidence: 99%

Integrated Assessment of Urban Overheating Impacts on Human Life

Nazarian

¹

,

Krayenhoff

²

,

Bechtel

³

et al. 2022

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Urban overheating, driven by global climate change and urban development, is a major contemporary challenge that substantially impacts urban livability and sustainability. Overheating represents a multifaceted threat to the well‐being, performance, and health of individuals as well as the energy efficiency and economy of cities, and it is influenced by complex interactions between building, city, and global scale climates. In recent decades, extensive discipline‐specific research has characterized urban heat and assessed its implications on human life, including ongoing efforts to bridge neighboring disciplines. The research horizon now encompasses complex problems involving a wide range of disciplines, and therefore comprehensive and integrated assessments are needed that address such interdisciplinarity. Here, our objective is to go beyond a review of existing literature and instead provide a broad overview and integrated assessments of urban overheating, defining holistic pathways for addressing the impacts on human life. We (a) detail the characterization of heat hazards and exposure across different scales and in various disciplines, (b) identify individual sensitivities to urban overheating that increase vulnerability and cause adverse impacts in different populations, (c) elaborate on adaptive capacities that individuals and cities can adopt, (d) document the impacts of urban overheating on health and energy, and (e) discuss frontiers of theoretical and applied urban climatology, built environment design, and governance toward reduction of heat exposure and vulnerability at various scales. The most critical challenges in future research and application are identified, targeting both the gaps and the need for greater integration in overheating assessments.

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“…The importance of the latter is often overlooked. Globally, carbon emissions associated with removing humidity loads (latent cooling) are slightly larger than temperature loads (sensible cooling) (Woods et al, 2022). One reason for the energy, carbon, and financial cost of latent cooling is the thermodynamic inefficiency of their removal.…”

Section: Indoor Thermal Environment and Innovative Cooling Strategiesmentioning

confidence: 99%

“…Improved efficiency (and lower cost of operation, an important characteristic of equitable heat resilience) comes from separating sensible and latent cooling, which has the twin benefits of increasing the efficiency of both processes. In this approach, water vapor is removed with desiccants or pressure-induced flows of water vapor across selectively permeable membranes (Claridge et al, 2019;Fix et al, 2021;Labban et al, 2017;Woods et al, 2022). Further separation of sensible and latent cooling can be achieved with radiant sensible cooling and latent cooling in a dedicated outdoor air system (DOAS), which provides limited sensible cooling to lower the temperature of the minimum airflow needed for indoor air quality (Ali et al, 2018;Fix et al, 2021;Labban et al, 2017).…”

Section: Indoor Thermal Environment and Innovative Cooling Strategiesmentioning

confidence: 99%

Integrated Assessment of Urban Overheating Impacts on Human Life

Nazarian

¹

,

Krayenhoff

²

,

Bechtel

³

et al. 2021

Preprint

View full text Add to dashboard Cite

Urban overheating, driven by global climate change and urban development, is a major contemporary challenge that substantially impacts urban livability and sustainability. Overheating represents a multifaceted threat to the well-being, performance, and health of individuals as well as the energy efficiency and economy of cities, and it is influenced by complex interactions between building, city, and global scale climates. In recent decades, extensive discipline-specific research has characterized urban heat and assessed its implications on human life, including ongoing efforts to bridge neighboring disciplines. The research horizon now encompasses complex problems involving a wide range of disciplines, and therefore comprehensive and integrated assessments are needed that address such interdisciplinarity. Here, our objective is to go beyond a review of existing literature and instead provide a broad overview and integrated assessments of urban overheating, defining holistic pathways for addressing the impacts on human life. We (a) detail the characterization of heat hazards and exposure across different scales and in various disciplines, (b) identify individual sensitivities to urban overheating that increase vulnerability and cause adverse impacts in different populations, (c) elaborate on adaptive capacities that individuals and cities can adopt, (d) document the impacts of urban overheating on health and energy, and (e) discuss frontiers of theoretical and applied urban climatology, built environment design, and governance toward reduction of heat exposure and vulnerability at various scales. The most critical challenges in future research and application are identified, targeting both the gaps and the need for greater integration in overheating assessments.Plain Language Summary Many major cities are faced with the compounding effects of climate change and rapid urbanization. One of the main challenges that result is urban overheating, which leads to negative impacts on human life (deteriorating health, productivity, and well-being) and urban energy systems. Heat exposure in cities, however, is only the trigger and there are other factors that influence impacts. Urban heat vulnerability exists when sensitive people and infrastructure are exposed to extreme heat, and negative impacts ensue if there is a lack of capacity to respond and adapt. Accordingly, to combat overheating challenges, it is critical that multidisciplinary solutions are integrated to mitigate exposure, reduce sensitivity, and increase adaptive capacities. This paper provides an integrated assessment of urban overheating literature, defining pathways for addressing the impacts on human life. We review the state-of-the-art methods used to quantify heat hazards and exposure, detail the sensitivity of people and infrastructure to overheating, and elaborate on the adaptive capacities that individuals and cities can undertake in response. We provide recommendations for both researchers and policymakers that will minimize overheating impacts. Thes...

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“…Conventional air conditioning and dehumidification are necessary instruments within most households, generally based on a refrigeration (condensation) mode that relies on dewing and is powered by electricity . The energy consumption for temperature and humidity control already accounts for about a fifth of the total electricity used in buildings around the world, reaching ∼10% of all global electricity consumption and ∼4% of the annual greenhouse gas emissions . This global energy demand is expected to triple by 2050, becoming the second-largest source of global electricity demand growth after the industry sector .…”

Section: Introductionmentioning

confidence: 99%

Hygroscopic and Photothermal All-Polymer Foams for Efficient Atmospheric Water Harvesting, Passive Humidity Management, and Protective Packaging

Lin

¹

,

Shao

²

,

Li

³

et al. 2023

ACS Appl. Mater. Interfaces

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Environmental humidity and thermal control are of primary importance for fighting global warming, growing energy consumption, and greenhouse gas emissions. Sorption-based atmospheric water harvesting is an emerging technology with great potential in clean water production and passive cooling applications. However, sorption-based humidity management and their hybrid applications are limited due to the lack of energywise designs of hygroscopic materials and devices. Herein, all polymeric 3D foams are developed and evaluated as hygroscopic and photothermal materials. The gas-foaming method generates closed-cell structures with interconnected hydrophilic networks and wrinkled surfaces, expanding hygroscopic, photothermal, and evaporating areas of the 3D foams. These unique advantages lead to efficient water vapor sorption in a wide broad relative humidity (RH) range of 50−90% and efficient water release in a wide solar intensity (0.4−1 sun) and temperature range (27−80 °C). The reversible moisture sorption/release in 50 adsorption/desorption cycles highlights the excellent durability of the 3D foams compared to conventional inorganic desiccants. The 3D foams disclose passive and efficient apparent temperature regulation in warm and humid environments. Moreover, the use of the 3D foams as loose fill for fruit preservation and packaging is demonstrated for the first time by taking the merit of the 3D foams' moisture-absorbing, quick-drying, cushioning, and thermal-insulating properties. This work presents an integrated design of polymeric desiccants and scaffolds, not merely delivering stable water adsorption/desorption but also discovering innovative hybrid applications in humidity management and protective packaging.

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Humidity’s impact on greenhouse gas emissions from air conditioning

Cited by 67 publications

References 29 publications

Integrated Assessment of Urban Overheating Impacts on Human Life

Integrated Assessment of Urban Overheating Impacts on Human Life

Integrated Assessment of Urban Overheating Impacts on Human Life

Hygroscopic and Photothermal All-Polymer Foams for Efficient Atmospheric Water Harvesting, Passive Humidity Management, and Protective Packaging

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