scholarly journals Performance Studies on Low GWP Refrigerants as Eco-friendly Alternatives for R134a in Household Refrigerator

Author(s):  
Saji Raveendran Padmavathy ◽  
Murugan Paradesi Chockalingam ◽  
Nithyanandhan Kamaraj ◽  
Godwin Glivin ◽  
Venkatesh Thangaraj ◽  
...  

Abstract Climate changes are a significant environmental issue and rises global temperature. The key environmental objectives are to reduce carbon emissions and to mitigate the climate change impacts. The household refrigerator is the most important emitter of greenhouse gases because they use high global warming potential refrigerants. The Kyoto Protocol states that the power consumption and environmental effects of household refrigerators must be reduced. In the development of future household refrigerator, the replacement of existing refrigerants and enhance its energy efficiency will play an important role. Therefore, the performance of a household refrigerator operating with various environmentally friendly refrigerant mixtures was investigated using analytical methods. This simulation was carried out using MATLAB software, and the REFPROP database was used to obtain thermophysical properties of the refrigerants. The findings have shown that the COP of HFO mixtures is drops from 4–20% compared to R134a. The R1234ze/R134a (90/10) is a better mixture, with its estimated COP and energy efficiency 3.7–16.4% and 4–16% respectively above the other mixtures considered in this analysis and its performance is very similar to the R134a. It could be a good substitute for R134a in the refrigerator to satisfy the Montreal and Kyoto Protocol expectations.

2018 ◽  
Vol 15 ◽  
pp. 231-237 ◽  
Author(s):  
Martín José Montero-Martínez ◽  
Julio Sergio Santana-Sepúlveda ◽  
Naydú Isabel Pérez-Ortiz ◽  
Óscar Pita-Díaz ◽  
Salvador Castillo-Liñan

Abstract. It is a matter of current study to determine potential climate changes in different parts of the world, especially in regions like a basin which has the potential to affect socioeconomic and environmental issues in a defined area. This study provides a comparison between several climate change indices trends of two very different basins in Mexico, one located in the northern arid region (the Conchos River basin) and the other in the southern humid area (the Usumacinta River basin). First, quality control, homogenization, and completion of the missing data were applied before calculating the climate change indices and their respective trends for the combined period 1961–1994. A clear warming signal was found for the two basins in addition to an increment in the DTR, in agreement with other studies in Mexico. Also, the Conchos River basin was found to be more humid and the Usumacinta River basin drier, in accordance to a supposed seesaw behavior indicated in previous analysis.


Plants ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 34 ◽  
Author(s):  
Ali Raza ◽  
Ali Razzaq ◽  
Sundas Mehmood ◽  
Xiling Zou ◽  
Xuekun Zhang ◽  
...  

Agriculture and climate change are internally correlated with each other in various aspects, as climate change is the main cause of biotic and abiotic stresses, which have adverse effects on the agriculture of a region. The land and its agriculture are being affected by climate changes in different ways, e.g., variations in annual rainfall, average temperature, heat waves, modifications in weeds, pests or microbes, global change of atmospheric CO2 or ozone level, and fluctuations in sea level. The threat of varying global climate has greatly driven the attention of scientists, as these variations are imparting negative impact on global crop production and compromising food security worldwide. According to some predicted reports, agriculture is considered the most endangered activity adversely affected by climate changes. To date, food security and ecosystem resilience are the most concerning subjects worldwide. Climate-smart agriculture is the only way to lower the negative impact of climate variations on crop adaptation, before it might affect global crop production drastically. In this review paper, we summarize the causes of climate change, stresses produced due to climate change, impacts on crops, modern breeding technologies, and biotechnological strategies to cope with climate change, in order to develop climate resilient crops. Revolutions in genetic engineering techniques can also aid in overcoming food security issues against extreme environmental conditions, by producing transgenic plants.


e-CUCBA ◽  
2021 ◽  
Vol 15 (8) ◽  
pp. 1-9
Author(s):  
HECTOR OCAMPO-ALVAREZ ◽  
FABIAN ALEJANDRO RODRÍGUEZ-ZARAGOZA

Coral reefs are highly productive marine ecosystems that harborahigh biodiversity. The forming organisms of these reefs are the scleractinian corals, which form symbiotic interactions with multiple microorganisms. One of the best known symbiotic interactions in these systems is the one established with the microalgae Symbiodinium. The microalgae produce through photosynthesis up to 90% of the energy required by the coral. On the other hand, Symbiodiniumreceives from the coral an appropriate niche, that protects Symbiodiniumfrom the external environment, from the competition with other organisms and predation; it also provides abundant nutrients produced by other coral symbiontshighlighting the bacteria. As well as this, multiple symbiotic interactions confer metabolic capabilities to corals, which have enabled their capacity to adapt to climate changes for millions of years. However, in recent decades coral reef ecosystems are being extensively decimated. Given the new characteristics of an environment with significant changes sometimes somewhat erratic, probably the interactions that initially provided ecological advantages to corals are no longer sufficient to overcome environmental adversities or that as a result of the changes generated in the environment. The diversity of microorganisms capable of interactions that can be formed with the few remaining microorganisms do not confer to the coral, sufficient adaptative advantages to face the challenge of climate change. In this essay, we argue about the possibility that a decrease in the stock of microorganisms capable of interacting with corals, as a result of marine pollution, is a cause of the loss of biological aptitude of corals to survive in the current global climate change.


Foods ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2769
Author(s):  
Daniel Grigorie Dinu ◽  
Valentina Ricciardi ◽  
Cosimo Demarco ◽  
Gianroberto Zingarofalo ◽  
Gabriella De Lorenzis ◽  
...  

The effects of global warming on plants are not limited to the exacerbation of summer stresses; they could also induce dormancy dysfunctions. In January 2020, a bud break was observed in an old poly-varietal vineyard. Meteorological data elaboration of the 1951–2020 period confirmed the general climatic warming of the area and highlighted the particular high temperatures of the last winter. Phenological records appeared to be significantly correlated to wood hydration and starch reserve consumption, demonstrating a systemic response of the plant to the warm conditions. The eight cultivars, identified by single-nucleotide polymorphism (SNP) profiles and ampelographic description, grown in this vineyard showed different behaviors. Among them, the neglected Sprino, Baresana, Bianco Palmento, and Uva Gerusalemme, as well as the interspecific hybrid Seyve Villard 12.375, appeared to be the most interesting. Among the adaptation strategies to climate changes, the cultivar selection should be considered a priority, as it reduces the inputs required for the plant management over the entire life cycle of the vineyard. Hot Mediterranean areas, such as Salento, are a battlefront against the climate change impacts, and, thus, they represent a precious source of biodiversity for viticulture.


2020 ◽  
Vol 10 (11) ◽  
pp. 3979
Author(s):  
Fabiana Silvero ◽  
Fernanda Rodrigues ◽  
Sergio Montelpare

Nowadays, the importance of implementing energy efficiency (EE) measures is growing significantly worldwide, based on its potential to reduce energy demands and mitigate climate change effects. Paraguay is a developing country with the highest per capita hydroelectric energy generation in the world, but only 18% of local consumption is hydroelectric and 41% of its energy matrix corresponds to oil products. This paper aims to analyse the importance the Country places on EE as a strategy towards sustainable development and to highlight as EE is an effective pathway to mitigate the climate changes and contrast their effects. The authors initially provide an insight into the climate scenarios for Paraguay and underline the effects of the climate changes on the buildings’ comfort. Subsequently, the authors provide, by resourcing a bibliographic review, a description of the Paraguayan sectors of greater energy consumption, its policies and targets set for increasing EE. Besides, the main EE projects developed by other neighbouring South American countries are analysed to show the level of development of each one in the scope of EE and to offer a reference basis of potential virtuous solutions to be adopted in Paraguay. A focus on the building sector is also made to provide a foundation for policy analyses to enhance EE in this sector. As a result of this review, evidence that EE is beginning to take part in Paraguay’s public policies was found, with the leaders becoming aware of its importance. Nevertheless, many concrete results could not be achieved as of yet and overcoming these barriers still involve a great challenge. Regarding the building sector, few advances have been noticed regarding the regulations of buildings’ thermal performance, a reason for which the National objectives set need to be more specific to achieve greater collective awareness to enforce them. Finally, key actions are recommended for Paraguay aiming to improve EE levels to face the climate change phenomenon.


2021 ◽  
Author(s):  
Julia Michalak ◽  
Josh Lawler ◽  
John Gross ◽  
Caitlin Littlefield

The U.S. national parks have experienced significant climate-change impacts and rapid, on-going changes are expected to continue. Despite the significant climate-change vulnerabilities facing parks, relatively few parks have conducted comprehensive climate-change vulnerability assessments, defined as assessments that synthesize vulnerability information from a wide range of sources, identify key climate-change impacts, and prioritize vulnerable park resources (Michalak et al. In review). In recognition that funding and planning capacity is limited, this project was initiated to identify geographies, parks, and issues that are high priorities for conducting climate-change vulnerability assessments (CCVA) and strategies to efficiently address the need for CCVAs across all U.S. National Park Service (NPS) park units (hereafter “parks”) and all resources. To help identify priority geographies and issues, we quantitatively assessed the relative magnitude of vulnerability factors potentially affecting park resources and values. We identified multiple vulnerability factors (e.g., temperature change, wildfire potential, number of at-risk species, etc.) and sought existing datasets that could be developed into indicators of these factors. To be included in the study, datasets had to be spatially explicit or already summarized for individual parks and provide consistent data for at least all parks within the contiguous U.S. (CONUS). The need for consistent data across such a large geographic extent limited the number of datasets that could be included, excluded some important drivers of climate-change vulnerability, and prevented adequate evaluation of some geographies. The lack of adequately-scaled data for many key vulnerability factors, such as freshwater flooding risks and increased storm activity, highlights the need for both data development and more detailed vulnerability assessments at local to regional scales where data for these factors may be available. In addition, most of the available data at this scale were related to climate-change exposures, with relatively little data available for factors associated with climate-change sensitivity or adaptive capacity. In particular, we lacked consistent data on the distribution or abundance of cultural resources or accessible data on infrastructure across all parks. We identified resource types, geographies, and critical vulnerability factors that lacked data for NPS’ consideration in addressing data gaps. Forty-seven indicators met our criteria, and these were combined into 21 climate-change vulnerability factors. Twenty-seven indicators representing 12 vulnerability factors addressed climate-change exposure (i.e., projected changes in climate conditions and impacts). A smaller number of indictors measured sensitivity (12 indicators representing 5 vulnerability factors). The sensitivity indicators often measured park or landscape characteristics which may make resources more or less responsive to climate changes (e.g., current air quality) as opposed to directly representing the sensitivity of specific resources within the park (e.g., a particular rare species or type of historical structure). Finally, 6 indicators representing 4 vulnerability factors measured external adaptive capacity for living resources (i.e., characteristics of the park and/or surrounding landscape which may facilitate or impede species adaptation to climate changes). We identified indicators relevant to three resource groups: terrestrial living, aquatic living (including living cultural resources such as culturally significant landscapes, plant, or animal species) and non-living resources (including infrastructure and non-living cultural resources such as historic buildings or archeological sites). We created separate indicator lists for each of these resource groups and analyzed them separately. To identify priority geographies within CONUS,...


Spatium ◽  
2011 ◽  
pp. 40-44
Author(s):  
Aleksandra Stupar ◽  
Zoran Nikezic

The global reality, intensively exposed to the challenges caused by climate changes, demands new ideas, methods and tools which could eventually prevent or mitigate the consequences of carbon emissions. Therefore, the contemporary cities, as focal points of the new global comprehension, have become testing grounds for numerous initiatives based upon imperatives of sustainability, environmental consciousness, energy efficiency and ?green? life style. In Serbia, experience in matters of the built environment has had a tendency to be formed exclusively on the basis of authentic local initiatives, aspirations, successes and failures. In the global effort for sustainable development, considering the commitments imposed by climate change and carbon emission, a greater reliance on results achieved elsewhere would be a welcome change. Consequently, this article will present and comment two eco-driven projects - Sarriguren and J?tk?saari, both covering a wide range of useful ideas, intriguing concepts and globally applicable solutions for the challenges caused by climate shifts.


Author(s):  
Ahmed Adam Mohamed ◽  
Redemtor Awuor Ojwang

Recent changes in climate over the last three decades, have increased the incidences of severe droughts and floods in Somalia. Moreover, the frequent internal conflicts increases the level of vulnerability of its citizens’ to climate change impacts. The UNDP puts at 5 million, the number of Somali people affected by drought incidences. Notably, factors such as income and marital status influence the vulnerability status of individuals in the region. This study assessed the vulnerability and impact of climate change of South Central Somali pastoralists based on income and marital status. The research was conducted through structured interviews and questionnaires and the sample size for the study was 400. The divorcees, were found to be the most vulnerable, compared to the married, singles and widows. On the other hand, the higher income earners were found to be less vulnerable to climate change impacts compared to the lower income earners. The findings demonstrate that marital status and income, play a key role in influencing the level of vulnerability of the individuals in the study area. The information can be used to formulate policies that will provide appropriate interventions to the most affected groups.


2021 ◽  
Vol 8 ◽  
Author(s):  
Bryony L. Townhill ◽  
Elena Couce ◽  
James Bell ◽  
Stuart Reeves ◽  
Oliver Yates

Climate change is already affecting the distributions of marine fish, and future change is expected to have a particularly large impact on small islands that are reliant on the sea for much of their income. This study aims to develop an understanding of how climate change may affect the distribution of commercially important tuna in the waters around the United Kingdom’s Overseas Territories in the South Atlantic. The future suitable habitat of southern bluefin, albacore, bigeye, yellowfin and skipjack tunas were modelled under two future climate change scenarios. Of all the tunas, the waters of Tristan da Cunha are the most suitable for southern bluefin, and overall, the environmental conditions will remain so in the future. Tristan da Cunha is not projected to become more suitable for any of the other tuna species in the future. For the other tuna species, Ascension Island and Saint Helena will become more suitable in the future, particularly so for skipjack tuna around Ascension Island, as the temperature and salinity conditions change in these areas. Large marine protected areas have been designated around the territories, with those in Ascension and Tristan da Cunha closed to tuna fishing. Although these areas are small relative to the whole Atlantic, these model projections could be useful in understanding whether this protection will benefit tuna populations into the future, particularly where there is high site fidelity.


2019 ◽  
Vol 23 (3) ◽  
pp. 370-392
Author(s):  
Dagnija Blumberga ◽  
Bin Chen ◽  
Alise Ozarska ◽  
Zane Indzere ◽  
Dace Lauka

Abstract Overview of research papers of International conference of Environmental and Climate Technologies (CONECT 2019) illustrates the wide range of topics covered in the issue. All overviewed articles are published in the Special Issue (Part I and Part II) of the Journal of Environmental and Climate Technologies. Scientific articles are divided into 5 thematic clusters: renewable energy resources, energy efficiency, policy and policy tools, waste management and bioeconomy that charts energy, bioeconomy, climate change and environment nexus.


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