Global Warming Potential Values Research Articles

Energy and Exergy Analysis of Vapor Compression Refrigeration System with Low-GWP Refrigerants

In this paper, a first- and second-law analysis of vapor compression refrigeration is presented to estimate and propose the replacement of R134 with working fluids having less global warming potential (GWP) and less exergy destruction and irreversibilities. Six different refrigerants were studied, namely, R717, R1234yf, R290, R134a, R600a, and R152a. A thermodynamic model was designed on Engineering Equation Solver (EES) software, and performance parameters were calculated. The model was deployed on all six refrigerants, while the used output parameters of performance were cooling capacity, coefficient of performance, discharge temperature, total exergy destruction, relative exergy destruction rates of different components, second-law efficiency, and efficiency defect of each component. The performance parameters were estimated at different speeds of the compressor (1000, 2000, and 3000 rpm) and fixed condenser and evaporator temperatures of 50 °C and 5 °C, respectively. The isentropic efficiency of the compressor was the same as the volumetric efficiency, and it was taken as 75%, 65%, and 55% at the compressor speeds of 1000 rpm, 2000 rpm, and 3000 rpm, respectively. A comparison of the performance parameters was presented by importing the results in MATLAB. It was found that the compressor had the highest exergy destruction compared to the other components. It was found that R152 was the refrigerant with zero ozone depletion potential (ODP) and a GWP value of 140 with less exergy destruction and irreversibilities. Moreover, it was easy to use R152a with good thermodynamic characteristics. It is estimated that R152a is a suitable replacement for R134a, as it can be used with few modifications.

Role of selenite on the nitrogen conservation and greenhouse gases mitigation during the goat manure composting process.

This study aimed to explore the roles of selenite (Se) on nitrogen conservation and greenhouse gases (GHGs) mitigation during the composting process. Six levels of Se(IV) dosages (i.e. 0, 2, 4, 6, 8 and 10 mg/kg) were examined for 80-day composting of goat manure and wheat straw mixtures, where the different blending proportions were marked as T1 (Control), T2, T3, T4, T5 and T6, respectively. The results showed that adding Se(IV) was beneficial for reducing NH3 by 3.50-42.41% by buffering pH and promoting nitrification. For N2O, it showed different responses to different Se(IV) dosages, and it was increased by 29.62-71.29% in T2-T4 but reduced by 30.45-69.54% in T5-T6. Methane (CH4), another main component of GHGs, was increased by 1.35-107.42% by adding 2-10 mg/kg Se(IV). To further evaluate the effect of Se(IV) on GHGs, global warming potential value was calculated, which was 103.32-499.80 and minimum value was in T5. Furthermore, the physicochemical indexes, especially temperature and OM, had vital effects on microbial community. Overall, the results obtained from this study demonstrated that the application of Se (IV) in composting was reasonable to generate Se-rich organic fertilizer, and the 8 mg/kg was suggested from perspectives of nitrogen conservation and GHGs reduction.

Benefits of wooden structure reuse: the case of an Austrian building

The building sector is responsible for 39% of greenhouse gas (GHG) emissions; thus, it has a significant amount of potential to reduce the effects of climate change. Several active- and passive solutions and strategies have been developed and proposed in the literature. Among them, wood is highlighted as a promising solution to minimize GHG from buildings. However, the benefits, especially in the circular economy, are not fully evaluated due to methodological choices. Motivated by this knowledge gap, this article aims to evaluate the benefits of wood reuse compared to traditional building construction solutions. For this purpose, we have calculated the environmental impacts of a building situated in Graz, Austria. Four different scenarios are considered. The first scenario is a fully reinforced concrete building. The second scenario is a structural beam-column made from reinforced concrete with walls made of concrete blocks. The third scenario is a beam-column made from reinforced concrete with external walls based on clay blocks. Finally, the last scenario is a full wooden building. Following the standardized life cycle assessment (LCA) method, global warming potential (GWP) is calculated through a 0/0 approach. These evaluations were made possible by correlating the impacts released from producing wooden elements and the uptake of biogenic carbon from the forest. Without considering the possibility of material reuse, the wooden structure has a 5 % lower GWP value than the reinforced concrete building. Comparatively, the other building scenarios have almost similar impacts as the building in reinforced concrete. In the case of material reuse, the wooden structure building shows potential to develop projects with 44% lower environmental impacts.

Life cycle climate performance (LCCP) evaluation model for electric vehicle heat pumps and emission reduction analysis of low-GWP refrigerants

<p indent="0mm">With the proposal of China’s carbon neutrality target and the official entry into force of the Kigali Amendment to the Montreal Protocol, the green and efficient development of the new energy vehicle heat pump is imperative, since China has the largest number of new energy vehicles in the world. The environmental-friendly heat pump with low global warming potential (GWP) is increasingly essential for the electric vehicle (EV) to save energy consumption and extend the driving range, it is beneficial to achieve the carbon neutrality from reducing both direct and indirect carbon emissions. The long-used R134a has a great climate impact due to its high GWP, researchers have been investigating heat pump systems with low-GWP refrigerants. Previously, the life cycle climate performance (LCCP) was a widely accepted metric to evaluate the carbon footprint of mobile air conditioning systems “from cradle to grave” for the classical engine vehicle, however, the new energy vehicle heat pump has significant differences from the mobile air conditioning systems, which makes the LCCP developed for MAC systems no longer applicable for the NEV heat pump system. Such LCCP analysis about EV heat pumps can hardly be found. To facilitate the EV industry and policymakers better understand the environmental impacts of those low-GWP refrigerants, this study provides a comprehensive LCCP analysis for the EV heat pumps based on the heat pump system bench test results, local climates (six cities: Beijing, Shanghai, Guangzhou, Phoenix, Fargo, and Chicago), local power supply characteristics, real-world driving patterns, vehicle cabin thermal sensation, and climate control load. Three low-GWP refrigerants, i.e., CO₂, binary blends of CO₂ and R41 (with GWP value of 49), M2 (R410A substitute with GWP value of 137), were compared against R410A and R134a. Results show that the system COPs in the energy consumption model are estimated within ±6.5%; In most regions, the heat pump can save 36%–69% of electricity for heating on electric vehicles compared to the conventional PTC heater system; The direct emissions depend on the refrigerant GWP and are almost unaffected by the climate. The indirect emissions are influenced by the climate, refrigerant type and the carbon intensity; among the indirect emissions, manufacturing and EOL disposal account for only 5% or so, while the major part is the emissions due to system operation; The R410A heat pump shows higher levels than R134a in both direct and indirect emissions, with 11%–36% increase in total; although M2 shows 2%–27% higher indirect emissions than R134a, it reduces 90% of the direct emissions. In general, it shows 3%–35% less total emissions compared to R134a for EV heat pump application; the direct emissions of the CO₂ heat pump can be neglected while the CO₂ system can reduce 7% of the indirect emissions only in cold climates such as Fargo. Thanks to its low direct emissions, the total LCCPs of the CO₂ heat pump are reduced by 6%–27% relative to R134a except in Shanghai (+20%); among the selected refrigerants, CO₂/R41 shows the lowest LCCP, reducing 5%–42% of total emissions relative to R134a in various climates, and 1%–21% less than the CO₂ system.

Environmental Life Cycle Assessment of Sorghum (sorghum bicolor) Production, Storage and Disposal in Ilorin, Nigeria

Nigeria is one of the major producers of sorghum grains in the world. The production and storage of the crop consumed resources, both biotic and abiotic and this could lead to some environment burden in form of emissions and pollutions. Therefore, this study was carried out to assess the environmental life cycle of sorghum, from production to storage and packaging for market using life cycle assessment model (LCA).The life cycle inventory data was collected for production, and storage operations of three scenarios of sorghum namely: storage in jute bags and fumigation in Warehouse (FW), usage of Bio-pesticide (BP) and NSPRIDUST (ND) as protectant. The inventory data collected was based on a functional unit of one hectare of land for production, and one ton of grains for storage operations respectively. The data were analyzed using “Ganzheitliche Bilanz” (GaBi) 8.7 software. Environmental impact categories generated were Global Warming Potential (GWP), Acidification Potential (AP), Eutrophication Potential (EP), Ozone Depletion Potential (ODP) and Human Toxicity Potential (HTP).The GWP values obtained for sorghum scenario using FW, BP, and ND were 6.850, 7.930 and 6.890 kg CO 2, respectively. The AP values for FW, BP and ND were 0.009, 0.012 and 0.009 kg SO 2, respectively, while EP values obtained for FW, BP and ND were 2.180, 3.010 and 2.070 E-3 kg Phosphate, respectively. The ODP values using FW, BP and ND were 8.96, 8.96, and 8.96 E-13 kg R11 respectively, while the HTP values obtained using FW, BP and ND were 4.150, 4.150 and 4.150 kg DCB, respectively.The research showed that the impact values of FW, BP and NS for sorghum scenario had not much difference. The research finding is recommended for environmentalists, grain producers and handlers. Keywords: Life Cycle Assessment, global warming, acidification, eutrophication, ozone layer depletion DOI: 10.7176/JEES/12-8-01 Publication date: August 31 st 2022

Environmental Impact Assessment of Solid Polymer Electrolytes for Solid‐State Lithium Batteries

Solid‐state batteries play a pivotal role in the next‐generation batteries as they satisfy the stringent safety requirements for stationary or electric vehicle applications. Notable efforts are devoted to the competitive design of solid polymer electrolytes (SPEs) acting as both the electrolyte and the separator. Although particular efforts to attain acceptable ionic conductivities and wide electrochemical stability widows are carried out, the environmental sustainability is largely neglected. To address this gap, here the cradle‐to‐gate environmental impacts of the most representative SPEs using life cycle assessment (LCA) are quantified. Raw material extraction and electrolyte fabrication are considered. Global warming potential values of 0.37–10.64 kg CO2 equiv. gelectrolyte −1 are achieved, where PEO/LiTFSI presents the lower environmental burdens. A minor role of the polymer fraction on the total impacts is observed, with a maximum CO2 footprint share of 0.61%. Following ecodesign approaches, a sensitivity analysis is performed to simulate industrial‐scale fabrication processes and explore environmentally friendlier scenarios. The electrochemical performance of SPEs is further analyzed into Li/LiFePO4 solid lithium metal battery cell configuration. Overall, these results are aimed to guide the ecologically sustainable design of SPEs and facilitate the implementation of next‐generation sustainable batteries.

Comparative Analysis of the Global Warming Potential (GWP) of Structural Stone, Concrete and Steel Construction Materials

The manufacturing and construction industries have always been large contributors to global CO2 emissions, largely as a consequence of material choices. Two of the most commonly used building materials are concrete and steel, but both of these industries have been identified as large sources of atmospheric CO2. Therefore, reducing the use of these materials and finding alternatives to them that meet the engineering requirements of a design, while also minimizing emissions, is becoming increasingly important. Stone in its natural form is a zero-carbon emission material and has strong physical properties that make it a viable substitute for concrete and steel, across a range of applications. Yet research into the potential use of stone by the construction industry remains rare. The aim of this research is to investigate whether the use of stone as a building product is a feasible alternative in terms of carbon emissions. This study compares data from 11 Environmental Product Declarations (EPDs) that provide Life Cycle Analysis (LCA) assessments of their considered product (i.e., types of dimensional stone, concrete, or steel). However, this research also highlights some shortcomings in the EPDs that point to a need for greater legitimate engagement with this tool, and for more consistency between the data being presented in EPDs. Global Warming Potential (GWP) data are compared between products to determine the difference in carbon emissions. The results indicate that GWP values for dimensional structural stone (135 kg.CO2/m3) are 45–75% lower than the concrete products considered in this investigation (246–514 kg.CO2/m3), and over 99% lower than certain steel products (22,294–29,202 kg.CO2/m3). This research indicates that stone is demonstrably better in terms of its GWP, and that a more extensive use of structural stone represents a key opportunity for the construction industry to reduce its CO2 emissions.

Environmental and enviroeconomic impacts of COVID-19 pandemic on commercial flights

PurposeThe purpose of this study is to determine and compare the total and per passenger HC, CO, NOx and CO2 emissions from aircraft landing and takeoff (LTO) cycle before and during the COVID-19 pandemic. In addition, it is aimed to determine the global warming potential (GWP), environmental impacts (EIs) and enviroeconomic cost (eco-cost) of these emissions in total and per passenger.Design/methodology/approachAnalyses were carried out with the help of the International Civil Aviation Organization’s Engine Emission Databank, using real flight data recorded by the airport authority.FindingsDuring the COVID-19 pandemic, total pollutant emissions (HC, CO, NOx and CO2) decreased between 23.7% and 30.8% compared with the pre-pandemic period. In addition, per passenger pollutant emissions increased during the pandemic. Compared with the pre-pandemic period, GWP, EI and eco-cost values decreased by 24.1%, 23.89% and 23.93%, respectively, in the pandemic. However, the per passenger GWP, EI and eco-cost values increased by about 10% compared with the pre-pandemic period.Practical implicationsThis study reveals the effects of COVID-19 in terms of EIs and environmental costs caused by aircraft in the LTO cycle.Originality/valueThe originality of this study is to calculate the pollutant emissions caused by aircraft in the LTO cycle with real flight data and to reveal the effects of the COVID-19 pandemic. The novelty of this study is the determination and comparison of total and per passenger pollutant emissions, GWP, EI and eco-cost before and during the pandemic.

Environmental Impact Assessment of Hole Conductor Layer Free and Flexible Organo Lead Iodide Perovskite Solar Cell

Perovskite solar cells (PSCs) have shown a significant increment in power conversion efficiency recently with advantages such as flexibility and low-cost roll-to-roll production. Prior to the commercialization of PSCs, it is significant to investigate its environmental performance with life cycle assessment method. In this work, cradle to gate LCA of solution-based organo-lead iodide perovskite solar cell performed according to the one reported literature method that comprises flexible Polyethylene terephthalate (PET) substrate and hole transport layer (HTL) elimination. Environmental impacts from the generation of 1 m2 of cell area production are determined in six International Reference Life Cycle Data System (ILCD) categories. It is found that the major impact comes from the fabrication of the aluminum metal electrode layer due to the high electrical energy required in the vacuum deposition process. The life cycle global warming potential (GWP) that the most widely used environmental indicator has been calculated for per kWh electricity production to make a comparison with commercial photovoltaic technologies. It is found that the HTL-free flexible (HFF) PSC needs 15-20 years of device lifetime to reach competitive GWP value with commercial PVs.

Direct and Residual Impacts of Olive-Mill Waste Application to Rice Soil on Greenhouse Gas Emission and Global Warming Potential under Mediterranean Conditions

The olive oil industry produces high amounts of waste, which need to be valorized in a more sustainable way as an alternative to its traditional use as an energy source, with high associated CO2 emissions. Rice (Oryza sativa L.) is one of the most important crops for global food security; however, the traditional cropping systems under flooding lead to an important decrease of soil quality, as well as relevant emissions of greenhouse gases (GHG). The aim of this study was to assess the GHG emission from rice fields amended with composted two-phase olive mill waste (C-TPOW), in Mediterranean conditions. A field experiment was carried in rice cultivated by the traditional system, either unamended (Control) or amended with C-TPOW (Compost). GHG emissions were measured over three years following a single C-TPOW application (80 Mg ha−1 only in the first year of study), so that the results found in the first and third years correspond to its direct and residual effects, respectively. Compost decreased CO2 emissions relative to Control by 13% and 20% in the first and third year after C-TPOW application, respectively. However, in the case of CH4 and N2O, increases in the total cumulative emission were recorded in Compost relative to Control throughout the study, in agreement with the highest β-glucosidase and urease activity observed in the amended soil. The values of global warming potential (GWP) and yield-scaled GWP increased by 14% and 11%, respectively, in Compost relative to Control in the first year, but no significant differences between treatments were observed three years after application for GWP and yield-scaled GWP. Therefore, the use of C-TPOW as soil amendment in rice fields could be a good option since its impact on GHG emissions seems to decrease over time, while the benefit for soil remained clear even after 3 years.

Environmental Impact Assessment of Na3V2(PO4)3 Cathode Production for Sodium‐Ion Batteries

Sodium‐ion batteries (NIBs) are key enablers of sustainable energy storage. NIBs use Earth‐abundant materials and are technologically viable to replace lithium‐ion batteries in the medium term. Na3V2(PO4)3, as a popular cathode for NIBs, requires further improvements to boost its electrochemical performance, particularly regarding the rate capability and operational lifetime. These strategies involve the incorporation of carbonaceous materials, heteroatom doping, morphology modification, or biopolymer incorporation. Considering the circular economy actions to foster environmentally sustainable battery industries, there is an urgent need to disclose the environmental impacts of battery production. A cradle‐to‐gate life cycle assessment methodology is used to quantify, analyze, and compare the environmental impacts of ten representative state‐of‐the‐art Na3V2(PO4)3 cathodes. Impacts are disclosed for 18 indicators normalized to 1 kg of cathode considering laboratory‐scale approaches. Global warming potential values of 423.9–1380.0 kg CO2‐equiv. kgcathode −1 and 539.8–1622.1 kg CO2‐equiv. kWhcathode −1 are obtained considering Na3V2(PO4)3/Na half‐cell configuration. Simple carbon additives mixed with NVP provide a good CO2 footprint‐to‐storage capacity balance, although the sacrificed capacity retention hinders reuse strategies. A sensitivity analysis demonstrates a 16.9–38.0% reduction transitioning from fossil‐based to renewable‐based energy mix. Herein, it is aimed to support battery developers and assist future advances in the development of sustainable cathodes applied into beyond‐Li‐ion technologies.

A computational drop-in assessment of hydrofluoroethers in Organic Rankine Cycles

Organic Rankine Cycles (ORCs) are experiencing a growing interest due to their ability to generate electricity from residual low waste heat sources. HFC-245fa is a representative working fluid for ORC applications, but it has recently been phased-out in new equipment because of its high global warming potential (GWP). In this work, the soft-SAFT molecular-based equation of state is used to evaluate the capacity of nine promising low-GWP hydrofluoroethers (HFEs) as alternative working fluids in ORC applications using different key performance indicators focused on energy efficiency and service fluids consumption. The thermodynamic model has been employed to characterize these fluids by describing saturated densities, vapor pressure, surface tension, temperature-enthalpy, and temperature-entropy diagrams, including further validation with binary mixtures. Then, based on technical criteria focused on the thermal efficiency and working and service fluids consumption, the soft-SAFT model has been used to conduct a feasibility study of HFEs as direct substitutes for HFC-245fa in such applications. Although pure fluids can not reach the same efficiency as the benchmark, HFE-356mmz, HFE-7000, and HFE-7100 appear as promising replacements, capable of approaching system requirements operating at low pressure with low cooling water and heating fluid flow rates, while exhibiting lower GWP values.

Spatiotemporal Model to Quantify Stocks of Metal Cladding Products for a Prospective Circular Economy

The traditional linear economy (LE) approach based on a “take-make-dispose” plan that has been used in building activities over a long period has a significant impact on the environment. In the LE approach, the used materials are usually sent to landfills rather than recycled, resulting in resource depletion and excessive carbon emissions. A circular economy (CE) is expected to solve these environmental problems by promoting material “closed-loop systems”. This study was intended to quantify and analyse the global warming potential (GWP) values of specific metal roofing and cladding products to promote CE thinking. A spatiotemporal model integrated with the life cycle assessment (LCA) tool was used to quantify the GWP value of the steel products in the investigated buildings. The study analysed ten case buildings located in six different cities in New Zealand: Auckland, Wellington, Hamilton, Palmerston North, Tauranga, and Christchurch. The production stages (A1–A3), water processing (C3), disposal (C4), and recycle, reuse, and recovery stages (D) were the focus of the study in analysing the GWP values of the product’s life cycle. The study found that the production stages became the most significant emitters (approximately 99.67%) of the investigated steel products’ GWP values compared to other selected life cycle stages. However, when considering the recycling stages of the steel products, the GWP value was reduced up to 32%. Therefore, by implementing the recycling process, the amount of GWP can be reduced, consequently limiting the building activities’ environmental impacts. In addition, the integration of spatial analysis and LCA was found to have potential use and benefit in future urban mining and the development of the CE approach in the construction industry.

The emission of greenhouse gases from flare gas condensates of petroleum units and the climatic index of emberger in Southern Iran

The emission level of the greenhouse gases resulted by the flared gas condensates of petroleum units and subsequent climatic changes determined by the Emberger index in southern Iran in 2019 was investigated. The monthly climatic data and the activities of gas flares in an 11-year period (2008-2018) were obtained from the Iranian National Oil Company and the Iranian Meteorological Bureau. The emission coefficients of the greenhouse gases including CO2, CO, N2O, and CH4 and the values of global warming potential (GWP) were calculated according to the IPCC 2006 manual. A total of 845142.4-ton CO2 per one month was produced by the flares. The monthly GWP ranged from 4 to 217714.8 Ton CO2 e/FU for all gases, and for CO2: 1 kg CO2/kg, N2O: 298 kg CO2/kg, CO: 1.9 kg CO2/kg, and CH4: 25 kg CO2/kg. The Emberger index indicated the climate of the research area during the 11-year period was arid, and in 2011 and 2015, due to relatively higher rain, it was semi-arid. A GWP of 10141708.8 (Ton CO2 e/FU) by the greenhouse gases indicates their significant contribution to the potential warming of the region, and the impact of such gases during the winter increases due to higher humidity.

Life Cycle Assessment of the Polyvinylidene Fluoride Polymer with Applications in Various Emerging Technologies

Polyvinylidene fluoride (PVDF) is one of the most popular fluoropolymers in the market. It is commonly used as pipes and cables, binder materials, and membrane materials. Lately, PVDF is being examined for applications in batteries, biomedical research, chemical engineering, and wastewater management. These PVDF applications cover most emerging technologies, which can be attributed to its outstanding physicochemical properties. With the global demand for PVDF in diverse technologies increasing significantly, it is imperative to quantify the environmental impacts associated with its production. Life cycle assessment (LCA) methodology is a standardized approach for evaluating the environmental impacts of novel materials. However, most previous LCA studies have not accounted for PVDF in a scientifically rigorous manner. While compiling the life cycle inventory (LCI) on PVDF, several kinds of surrogates were chosen to bridge the data gap, rather than establishing the new dataset for PVDF. When we investigate the similarities and differences between PVDF and popular surrogates regarding the synthesis pathways, adopting surrogates to replace PVDF becomes difficult. Due to the use of these surrogates, the global warming potential (GWP) calculated in the literature varies significantly, with a difference of 60.7 kg CO2 equiv between the highest and lowest estimates. After evaluating the life cycle environmental profiles of those commonly used surrogates, we find that the application of surrogates is hardly reliable; besides, the PVDF inventory dataset is underestimated. For this reason, we model the PVDF production process according to the commercialized synthesis approach and assess the cradle-to-gate impacts, which lowers uncertainty. The impact assessment on the PVDF inventory dataset results in an acceptable GWP value (55.8 kg CO2 equiv/kg PVDF), but a high cumulative energy demand (CED, 756 MJ equiv/kg PVDF), due to the large demand for chlorine during the production of vinylidene fluoride (VDF). In terms of uncertainty analysis, the upper and lower bounds for the newly developed LCI dataset for PVDF are 801 and 714 MJ equiv for CED values and 59.1 and 52.8 kg CO2 equiv for GWP values, respectively. Notably, this is the first study to develop a detailed LCI for PVDF involved in emerging technologies.

Thermo-soil weathering and life cycle assessment of carbon black, silica and cellulose nanocrystal filled rubber nanocomposites

Carbon black (CB) and silica (Sil) as rubber reinforcement have raised environmental concerns for being high resources consumptive and less susceptible towards biodegradability. Cellulose nanocrystal (CNC) has demonstrated great potentials for use as biodegradable nanofillers in rubber nanocomposites while evaluation of its environmental impacts with optimal end-of-life (EOL) choices is not carried out. To simulate realistic EOL, thermo-oxidative aging and soil burial aging behaviors of rubber nanocomposites with 33.3% filler were performed. The environmental weathering performance modeled with the help of life cycle assessment (LCA) illustrates increased biodegradation susceptibility with partial replacement of CB or Sil with CNC in the nanocomposites, hence promoting the environmental solutions for waste minimalization by enhancing the biodegradability potentials. In terms of LCA, the CNC incorporation contributes more to the environmental impacts in manufacturing but greatly lowers the EOL choices, by reducing the global warming potential values.

Comparative Life Cycle Assessment of a Historic and a Modern School Building, Located in the City of Naoussa, Greece

Life Cycle Assessment is often applied as a methodological approach for evaluating the environmental performance and impact of the building sector, including building stock. In the present study, two school buildings, located in the city of Naoussa, N. Greece were analyzed, including a historic and a modern one. The survey concerned on-site inspection and documentation of the structures, data collection and analysis, Life Cycle Impact assessment, as well as comparative evaluation of the results. The objective was to indicate the constructional and performance characteristics of the buildings, as well as to comparatively evaluate their environmental performance and impact. Since historic school buildings still function as educational units, these aspects are crucial and may determine their future operation and use. For LCA, the expected life span of the buildings was taken into account (60 years for the modern school and 140 years for the historic one), as well as all life cycle stages (product, construction, use, end of life, beyond building life). Various indicators were assessed, such as Global Warming Potential (GWP), Fossil Fuel Consumption, Total Primary Energy, Non-Renewable Primary Energy. From the correlation of the results, it was asserted that although the two buildings present similar operational characteristics and needs, they have different environmental performances and impacts, mainly attributed to their different service life and structural characteristics. Although the operational GWP value of the historic building is higher (due to the extended life span), the embodied one is significantly lower (due to the natural materials used for its construction). Other indicators, such as fossil fuel consumption are also higher in the case of the modern school building, indicating that its environmental footprint is more intense.

Integrating life cycle assessment and a farmer survey of management practices to study environmental impacts of peach production in Beijing, China.

While intensive peach production has expanded rapidly in recent years, few studies have explored the environmental impacts associated with specific regional systems or the optimal management strategies to minimize associated environmental risks. Here, data from a survey of 290 native farmers were used to conduct a life cycle assessment to quantify the acidification potential (AP), global warming potential (GWP), eutrophication potential (EP), and reactive nitrogen (Nr) losses in peach production in Pinggu District, Beijing. Total annual Nr losses, and GWP, AP, and EP values for peach production in Pinggu District were respectively 10.7kgN t-1, 857kg CO2-eq t-1, 12.9kg SO2-eq t-1, and 4.1kg PO4-eq t-1. The principal driving factors were fertilizer production, transportation, and application, which togetheraccounted for 94%, 67%, 75%, and 94% of Nr losses, GWP, AP, and EP, respectively. In the high yield, high nitrogen-use efficiency (HH) group, relative values of Nr losses, GWP, AP, and EP were respectively 33%, 25%, 39%, and 32% lower than the overall averages for 290 orchards. Further analyses indicate that improved farming practices such as decreasing application rates of fertilizers, increasing proportion of base fertilization rate, and proper fertilization frequency in the HH group were the main reasons for these orchards' better performance in peach yields and partial factor productivity of nitrogen fertilizer, and their reduced environmental impacts. These results highlight the need to optimize nutrient management in peach production in order simultaneously to realize both environmental sustainability and high productivity in the peach production system.

Flammability and performance studies of eco-friendly ternary refrigerant mixtures used in vapour compression systems.

The present article analyses the refrigerant safety parameters flammability, global warming potential (GWP) and coefficient of performance (COP) for twenty-seven combinations that contain two flammable and one non-flammable (dilutant) component. The flammability of the flammable refrigerants R290, R600, R600a, R152a and R161 were investigated with different dilutants such as R245fa, R13I1 and R134a. To determine the minimum inerting concentration (which decides the flammable zone), two methods were used: thermal balance method (TBM) and the modified thermal balanced method (MTBM). The MICs estimated with both the methods are compared against the 50 experimental datapoints available in the literature (for different ternary mixtures). It was found that for all the ternary mixtures, majority of the MIC values estimated with MTBM are within ± 8% while with TBM are within ± 30%. Fifty-five ternary mixture compositions were identified (from the proposed twenty-seven mixture combinations) using the MICs predicted by MTBM. The COPs of the identified mixtures M1-M6, M8-M12, M14-M24, M26-M30, M34-M39 and M53-M54 are estimated to be less than 10% of the COP of R134a (at the same operating conditions). It is also estimated that the corresponding GWP value of the mixtures (M1 to M6, M8 to M12, M14 to M24, M26 to M30, M34 to M39, M53 and M54) are reduced by 91 to 99% when compared to R134a (GWP = 1300).

Global temperature goals should determine the time horizons for greenhouse gas emission metrics

Emission metrics, a crucial tool in setting effective exchange rates between greenhouse gases, currently require an arbitrary choice of time horizon. Here, we propose a novel framework to calculate the time horizon that aligns with scenarios achieving a specific temperature goal. We analyze the Intergovernmental Panel on Climate Change Special Report on Global Warming of 1.5 °C Scenario Database to find that time horizons aligning with the 1.5 °C and 2 °C global warming goals of the Paris Agreement are 24 [90% prediction interval: 7, 41] and 58 [90% PI: 41, 74] years, respectively. We then use these time horizons to quantify time-dependent emission metrics for methane. We find that the Global Warming Potential (GWP) values that align with the 1.5 °C and 2 °C goals are GWP1.5 °C = 75 [90% PI: 54, 107] and GWP2 °C = 42 [90% PI: 35, 54]. For the Global Temperature change Potential (GTP) they are GTP1.5 °C = 41 [90% PI: 16, 102] and GTP2 °C = 9 [90% PI: 7, 16]. The most commonly used time horizon, 100 years, underestimates methane’s GWP and GTP by 34% and 38%, respectively, relative to the values we calculate that align with the 2 °C goal and by 63% and 87%, respectively, relative to the 1.5 °C goal. To best align emission metrics with the Paris Agreement 1.5 °C goal, we recommend a 24 year time horizon, using 2045 as the endpoint time, with its associated GWP1.5 °C = 75 and GTP1.5 °C = 41.