GWP Reduction Research Articles

Co-amendment of dicyandiamide with waste carbonization products into composting: Enhanced fertility, reduced gas emission and increased economic benefits

Dicyandiamide (DCD) could reduce composting nitrogen (N) losses, but the decomposes at high temperatures limited its efficacy, which might be mitigated by co-application with biochar (BC) and wood vinegar (WV). Our study revealed that DCD alone or co-applied with BC and WV did not reduce N2O emissions during the composting of chicken manure and wheat straw. However, it significantly decreased NH3 and CH4 emissions by 22.6–45.6% and 53.8–85.6%, respectively, equivalent to a 24.1–44.8% reduction in GWP compared to the control. Furthermore, the combined use of DCD with BC and WV enhanced total N content by 5.6–36.6%, increased the compost accumulation temperature by 3.8–6.1%. DCD alone addition increased the compost dissolved organic matter (DOM) content by 12.2%, and when coupled with BC and WV, it enhances the biological index value to promote new DOM generation. DCD combined with BC could increase the final humus content of compost, thereby enhancing its quality, which approach also produced greater economic benefits (266.3 CNY t−1), compared to conventional composting. In conclusion, co-application of DCD with BC and WV in composting not only reduces the emission of NH3, N2O and CH4, but also increases the compost fertility and provides more economic benefits.

Intensification of valorization of cooked rice water through energy-efficient synthesis of drop-in biofuel (butyl levulinate): engine performance, emission profile, and environmental impact assessments.

For the first time, an energy-efficient and eco-friendly technology for the conversion of abundantly available kitchen waste, specifically waste cooked rice water (WCRW) to drop-in- biofuels, namely, butyl levulinate (BL), has been explored. The synthesis of BL was accomplished employing butyl alcohol (BA) and WCRW in an energy-efficient UV (5W each UVA and UVB)-near-infrared (100W) irradiation assisted spinning (120rpm) batch reactor (UVNIRSR) in the presence of TiO2-Amberlyst 15 (TA15) photo-acidic catalyst system (PACS). The optimal 95.81% yield of BL (YBL) could be achieved at 10 wt% catalyst concentration, 60°C reaction temperature, 80min time, and 1:10 WCRW: BA concentration as per Taguchi statistical design. Moreover, additional combination of different PACS such as TiO2-Amberlyst 16, TiO2-Amberlyst 36, and TiO2-Amberlite IRC120 H rendered 86.72% YBL, 90.04% YBL, and 93.47% YBL, respectively, proving superior efficacy compared to individual activity of the acidic catalysts and photocatalysts. The heterogeneous reaction kinetics study for TA15 PACS suggested Langmuir-Hinshelwood model to be the best fitted model. A significant 63.33% energy could be saved by UVNIRSR as compared to conventional heated reactor at the optimized experimental condition using PACS TA15. An overall alleviation in environmental pollution with 59.259% reduction in GWP, 15.254% decline in terrestrial ecotoxicity, 18.238% diminution in marine ecotoxicity, 17.25% decrease in ozone formation affecting human health, 5.865% reduction in human non-carcinogenic toxicity, 18.65% diminution in ozone formation affecting terrestrial ecosystem, 55.17% significant decrease in terrestrial acidification, and 25.619% mitigation in fresh water ecotoxicity could be observed. Furthermore, BL-biodiesel-diesel blends (3% BL, 7% biodiesel, and 90% diesel) exhibited significant reduction (25.45% and 36%, respectively, for CO and HC) in harmful engine exhaust emissions demonstrating environmental sustainability of the overall process.

Synergistic optimization: A comprehensive life cycle assessment for high-performance concrete with recycled aggregates and Next-Gen nylon waste fibers

The increasing use of natural resources and pollution caused by construction industries has spurred interest in eco-friendly materials such as recycled aggregates and recycled fibers. This research focuses on evaluating the effects of incorporating varying proportions of RCA and NWFs into HPC on its engineering characteristics and emissions. The environmental effects of the formulated blends on the HPC mixes were evaluated. The system boundary was determined based on cradle-to-gate theory, and Ecoinvent 3.10 was used as the background database for assessing the impacts of concrete mixes. Life cycle Impact assessment was carried out with the help of SimaPro software using CML baseline method. The findings reveal that introducing 0.25–0.5 % NWFs optimizes STS for all RCA percentages. NWFs also effectively mitigate the negative influence of RCA on CS. Incorporating 0.25 % NWFs enhances durability aspects related to permeability. Emissions related to CS are minimized in concrete mixes with 0.25 % NWF, particularly at 75 % RCA substitution levels. Portland cement dominates emissions in concrete, constituting 84.03 % without RCA and escalating to 91.35 % at complete substitution. It significantly influences the GWP, ETP and ADP. NCA exerts the highest environmental impact on FAETP 18.53 % without RCA and notably affects ODP and HTP, while RCA proves more sustainable, with a 66 % reduction in GWP compared to NCA, due to its recycled origin and lower energy demands in production. The optimal transport distance for 75RCA ranges from 25 km to 145 km with specific limits for different impact categories.

Life cycle assessment of post-combustion carbon capture and storage for the ultra-supercritical pulverized coal power plant

In this paper, different emerging post-combustion technologies, i.e., monoethanolamine (MEA), aqueous ammonia, pressure swing adsorption (PSA), temperature swing adsorption (TSA), membrane and calcium looping, were applied to an ultra-supercritical coal-fired power plant for carbon capture. A ‘cradle-to-grave’ life cycle assessment (LCA) was conducted to evaluate the technical performance and environmental impacts of the power plant with six emerging carbon capture technologies. Carbon capture significantly influences the impact categories directly associated with flue gas emission. The application of carbon capture reduced the GWP in the range of 49–75 %. TAP also reduced in the range of 18–51 %. However, the human toxicity potential, eutrophication potential, ecotoxicity potential and particulate matter formation potential increased due to energy and resource consumption in the upstream and downstream processes. For the life cycle water consumption potential, it decreased by 8 % with calcium looping, whereas it increased in the range of 36–75 % with other post-combustion technologies. The highest reduction in GWP and the least reduction in power efficiency was observed in calcium looping because of the high-temperature heat recovery from flue gas and elimination of complex solvent manufacturing. The plant with aqueous ammonia and membrane separation had the second and third highest reductions in GWP. In addition, the lowest values for TAP, FEP, and MEP were obtained in the membrane system. With MEA for CO2 capture, the total GWP value of the plant is slightly higher than these three technologies mentioned above, and the highest HTPc, FETP, and METP can be observed in this case. TSA and PSA have the most significant environmental impacts in most categories due to higher energy requirements.

Technical, economic and ecological assessment of European sustainable aviation fuels (SAF) production

AbstractMultiple options for sustainable alternatives to fossil kerosene have been assessed. The route using biomass gasification, hotgas cleaning, hydrogen addition (derived from water electrolysis using renewable power), Fischer-Tropsch synthesis and product upgrading towards ASTM D7566 certified SAF has technical, economic and environmental advantages to be discussed in detail. The technical assessment shows carbon resp. energy efficiency of fuel production at 61% resp. 55%. The economic assessment of brown-field installations in Finland predicts costs in the range of 1.00 €2019/l. For the evaluation of 200 MWth biomass plus 160.2 MWe grid power plant size, an electricity price and biomass price of 42 €2019/t and 51 €2019/MWh were assumed, respectively. The environmental assessment shows a global warming potential reduction of 91% (corresponds to 8.8 gCO2-eq./MJFuel,LHV) compared to fossil fuel using Finnish wind energy and biomass residues, far better than the required 65% GWP reduction of the European RED II regulation. Based on the techno-economic and environmental assessment of the preferred FT route, a European deployment potential between 10 and 60 Mt/a SAF seems achievable in early 2030 years. The authors propose to implement appropriate regulation with high urgency.

Evaluation of Biochar Addition to Digestate, Slurry, and Manure for Mitigating Carbon Emissions

The contribution of animal waste storage on GHG emissions and climate change is a serious issue for agriculture. The carbon emissions that are generated from barns represent a relevant source of emissions that negatively affect the environmental performance measures of livestock production. In this experiment, CO2 and CH4 emissions from different animal wastes, namely, digestate, slurry, and manure, were evaluated both in their original form and with a biochar addition. The emissions were monitored using the static camber methodology and a portable gas analyzer for a 21-day period. The addition of biochar (at a ratio of 2:1 between the substrates and biochar) significantly reduced the emissions of both gases compared to the untreated substrates. Slurry exhibited higher emissions due to its elevated gas emission tendency. The biochar addition reduced CO2 and CH4 emissions by 26% and 21%, respectively, from the slurry. The main effect of the biochar addition was on the digestate, where the emissions decreased by 45% for CO2 and 78% for CH4. Despite a lower tendency to emit carbon-based gases of manure, biochar addition still caused relevant decreases in CO2 (40%) and CH4 (81%) emissions. Biochar reduced the environmental impacts of all treatments, with a GWP reduction of 55% for the digestate, 22% for the slurry, and 44% for the manure.

A holistic framework of biochar-augmented cementitious products and general applications: Technical, environmental, and economic evaluation

In the context of the circular economy, the development of innovative and low-carbon concrete that incorporates different kinds of waste materials is gaining attention among the research community, regulatory agencies, and policymakers. These materials can be incorporated into concrete mixtures as aggregates or as fillers for improvement of product properties. This study aims to identify reliable designs for biochar-augmented cementitious products and general applications through technical, environmental, and economic assessments. The outcomes demonstrate that 5 wt% biochar addition could enhance the compressive strength of the final products. Using biochar, together with other recycled materials, can enormously reduce the environmental impacts, especially for global warming, enabling biochar-augmented cementitious products and general application as carbon-negative resources. The highest GWP reduction reached −720 kg CO2/tonne, equal to a 200% saving. A high quantity of biochar could be included in several specific applications (up to 60 wt%). The economic assessment highlights that the proposed designs are cost-effective and carbon tax can be significantly reduced. Carbon credits can also be earned for some carbon-negative designs. These findings can serve to mitigate GHG emissions and provide decision-makers with a reliable and holistic framework towards the goal of carbon neutrality.

The “green” use of fluorocarbons in Cherenkov detectors and silicon tracker cooling systems: challenges and opportunities in an unfolding era of alternatives

Saturated fluorocarbons (SFCs) of form CnF(2n+2) are chosen for their optical properties as Cherenkov radiators, with C4F10 and CF4 currently used at CERN in the COMPASS and LHCb ring imaging Cherenkov detectors. Their non-conductivity, non-flammability and radiation-resistance also make SFCs ideal coolants: C6F14 liquid cooling is used in all LHC experiments, while C3F8 is used for the evaporative cooling of TOTEM and the ATLAS silicon tracker. These fluids, however, have high global warming potentials (5000–10000*GWPCO2), and represented around 36% of CERN’s CO2-equivalent emissions in 2018. There is thus an impetus to reduce their use, losses in purification and wastage through leaks, through improved monitoring and closed circulation system design. Newer spur-oxygenated fluoro-ketones, for example from the 3 M NOVEC® range, with CnF2nO structures, can offer similar performance to SFCs with but with very low, or zero GWP. Although these fluids do not yet exist in large quantities over the full CnF2 “matrix” the radiation tolerance and thermal performance of NOVEC 649 (C6F12O) was sufficiently promising for it to be chosen as a C6F14 replacement for cooling silicon photomultipliers. Additionally, subject to optical testing, NOVEC 5110 (C5F10O) could (if blended with nitrogen) replace both C4F10 and CF4 in Cherenkov detectors. Lighter molecules (for example C2F4O, with similar thermodynamics to C2F6)—if and when available in industrial quantities—might allow lower temperature operation than evaporative CO2 in future silicon trackers operated at very high luminosity. Ultrasonic gas mixture analysis is very sensitive to concentration changes of a heavy vapour in a light carrier, and is used—in the only such fluorocarbon coolant leak monitoring system operating at LHC—for real-time monitoring of C3F8 coolant leaks from the ATLAS pixel and SCT silicon trackers into their nitrogen-flushed environmental volumes. A typical C3F8 sensitivity of better than 10−5 is achieved. Advanced new ultrasonic algorithms allow measurement of the concentrations of a pair of gases of particular interest on top of a varying known baseline of other gases. The technique is thus of considerable value in leak monitoring and could be used to blend fluoro-ketones with nitrogen or argon to reduce the GWP “load” of large volume atmospheric pressure gas Cherenkov radiators without the recourse to higher-pressure noble gas approaches. This paper outlines an approach to GWP reduction with fluoro-ketone fluids and the blending of heritage SFCs or fluoro-ketones with lighter gases using ultrasonic monitoring and control. Possible avenues for the use of fluoro-ketones in liquid phase and evaporative cooling of silicon trackers are discussed.

Carbon and craft: Lessons from the deconstruction, relocation, and reuse of a traditional Japanese house’s timber structure

This paper presents and analyses the Chair Laboratory in Kawaguchiko, Japan as a case study of structural reuse. An inventory analysis is conducted from collected data, followed by a life-cycle-cost analysis of deconstruction, transporting, and reassembling the structure. The results are compared to two alternative schemes (timber non-reuse and steel) to benchmark the savings associated with reuse. The material quantity take-down and life-cycle-cost analysis indicate a 46%-71% reduction in GWP due to reuse (on the order of 17-20 kg CO2e/m2 of savings), at the expense of a 39% increase in cost. The cost increase is dominated by additional labour-hours for disassembly and adjustments. This data presented in this reuse case study gives realistic quantitative and qualitative insights on the feasibility, benefits, and barriers to reuse. Policy-makers and designers can use these insights to inform policies and make design decisions that encourage structural reuse and, consequently, a lower-carbon built environment.

Production-Process Simulation and Life-Cycle Assessment of Metakaolin as Supplementary Cementitious Material

An environmental assessment of metakaolin as a supplementary cementitious material (SCM) through an integrated production-process-simulation and Life-Cycle-Assessment (LCA) approach is presented in this work. Initially, process simulation models were developed to reproduce the basic stages of the metakaolin production process. The effect of various operational parameters and scenarios, such as calcination temperature, moisture of raw material and associated drying, exhaust gas recirculation and the use of alternative-fuel combustion to provide kiln heat requirements, was evaluated. The resulting process heat-demand and CO2-emission computations were used as inputs in the LCA along with upstream literature data using a cradle-to-gate approach. LCA results focused on the most relevant environmental impact category of cement production, the Global Warming Potential (GWP (100)). The major findings showed a strong influence of process temperature and kaolin humidity on the lifecycle GWP, since both parameters affected not only the core-process heat demand but also the upstream impact related to fossil-fuel extraction, processing, transportation and distribution. Recirculating the exhaust provided a GWP reduction potential of up to 19%. In all examined production scenarios, metakaolin depicted a lower Global Warming Potential compared to clinker due to the avoidance of emissions related to limestone calcination. As regards the impact contribution of fuels, coal was responsible for higher onsite emissions and natural gas indicated higher upstream emissions. The GWP (100) could be further reduced when alternative waste fuels such as plastic waste, MSW (municipal solid waste) and tires were used. The LCA results have been cross-checked with previous literature reports, and the corresponding deviations are accordingly explained. In any case, the LCA results of different studies are rarely directly comparable due to the numerous assumptions required, which cannot be identically replicated.

Life cycle assessment of rainbow trout farming in the temperate climate zone based on the typical farm concept

Fish from aquaculture has the ability to meet consumer demand for a healthy and sustainable diet. The environmental footprint of fish farming depends largely on the method of production. Trout production in the temperate climate zone in open flow-through systems using the natural hydraulic gradient of streams as freshwater supply is energy efficient relative to more intensive systems. To investigate the possibility of reducing global warming potential, eutrophication potential, acidification potential, and ozone layer depletion associated with rainbow trout (Oncorhynchus mykiss) production in southern Germany, a comprehensive dataset collected under the typical farm framework was analyzed and a cradle-to-gate life cycle assessment was conducted. The impact of feed source (plant- and fish-based) was analyzed, as well as that of photovoltaic panels installed over the production area. Calculated emissions per kg fish live weight were 1.18 kg CO2eq, 7.89e−8 kg CFC11eq, 0.00552 kg SO2eq, and 0.0257 kg PO4eq. Full covering of the production area with photovoltaic panels, compared to the current ∼40% coverage, was estimated to provide a reduction of 1.04 kg CO2eq, resulting in emissions of 0.773 kg CO2eq per kg fish live weight. Feeds containing 35% and 61.8% fishmeal were associated with lower emissions compared to 100% plant-based, with a reduction in GWP of 0.79 kg CO2eq in the 61.8% fishmeal variant. Results showed that the use of photovoltaic panels can significantly reduce rainbow trout culture impact on the analyzed environmental impact categories. Feed containing fishmeal has a lower impact on the analyzed environmental impact categories. Alternatives such as insect meal and sustainable plant alternatives should be the focus of future research.

Searching for suitable lubricants for low global warming potential refrigerant R513A using molecular-based models: Solubility and performance in refrigeration cycles

• Accurate molecular thermodynamic model for R513A/lubricants in refrigeration cycles. • Rigorous energetic investigation of refrigeration cycles with thermodynamic postulates. • PEC5 optimal lubricant for R513A, in view of solubility, miscibility and viscosity. • Procedure allowed quantifying impact of the presence of lubricant on the COP. • Presence of PEC5 in the mixture up to 5% weight led to COP decrease of 3%. Following environmental regulations, refrigerant R134a (Global Warming Potential GWP = 1430), commonly used in air conditioning applications, is required to be replaced by refrigerants with lower GWP. Among them, R513A is investigated as an excellent alternative, with a GWP reduction of 56% compared to R134a. However, further studies are needed in order to assess its use for this application. In this work, the molecular-based polar soft-SAFT equation has been employed to predict the vapour-liquid equilibria (VLE) of R513A and selected lubricants, searching for the optimal lubricant and their performance on a vapour compression refrigeration cycle. First, the binary VLE of the commercial lubricants from the Pentaerythritol Esters (PECs) and Polyethylene Glycol Dimethyl Ethers (PEGDMEs) families with R1234yf and R134a were assessed versus available experimental data, by developing the appropriate molecular models and parameters. Then, the models were used to predict the properties of the ternary mixtures containing the two refrigerants and the lubricants. PEC5 was found to be the optimal lubricant for R513A, considering a balance between solubility, miscibility and viscosity. Molecular modelling combined with thermodynamic and energetic analysis allowed to calculate the performance of a vapour compression refrigeration cooling cycle, quantifying the impact of the presence of the lubricant on the COP. The presence of PEC5 in the mixture was not significant, staying below a COP decrease of 3% in all cases considered, while for TrEGDME, its presence reduced the COP up to 6.1%. The procedure used here allows tuning the performance of the refrigerant/lubricant pair, in a step forward on the search for low GWP refrigerants in air conditioning systems.

Non-stationary and LCA analysis of impurity adsorption using Kanuma clay and HAS-Clay in a Bio-H production system

In recent years, fuel cell (FC) applications have shown potential in the reduction of greenhouse gas (GHG) emissions, leading to an increase in demand for hydrogen fuel. The current source of hydrogen is generally fossil fuel origin. Therefore, for mitigating GHG emissions in the hydrogen production stage, we focused on the biomass-derived hydrogen (Bio-H2) production process. In this study, we discuss the environmental impacts of Bio-H2 through the biomass pyrolysis process of Blue Tower (BT) biomass gasification. The bio-syngas contains H2S, HCl, and NH3 as impurities, which can reduce the performance of FCs. In our previous experimental studies, we used hydroxyl aluminum silicate clay (HAS-Clay) as an adsorbent for removing impurities. However, based on the life cycle assessment methodology, it was found that the impact of HAS-Clay was higher, indicating that the environmental contribution of the one through operation using HAS-Clay would be lower. Thus, in this study, using Kanuma clay, which is a natural resource and lower impact adsorbent, we used the desulfurization test and designed an optimal process to mitigate its eco-burden and maintain removal performance. Finally, using the dynamic process simulator of ANSYS fluent (2020 R1), we compared the proposed process to the conventional process in terms of plant performance and evaluated the environmental impacts. The results showed that there was a 12.3% reduction in GWP due to the replacement of Kanuma clay and HAS-Clay as compared to ZnO, a chemical adsorbent.

R513A Soğutucu Akışkanın Termodinamik Özelliklerini Tahmin Etmek İçin GEP Tabanlı Model Yaklaşımı

The changes in the politic and environmentally are highly effective in refrigerant choices. Nowadays it is critical using environmentally friendly and energy-efficient refrigerants for a sustainable future. The R513A refrigerant provides both GWP reduction and increases energy efficiency. Accurate estimates of thermodynamic properties of refrigerant are critical when considering the changing of temperature in a small interval. Many data of thermodynamic properties of refrigerants are hard-to-reach data from literature and tables. In the present study, thermodynamic properties such as entropy, enthalpy and density are modelled using gene expression programming (GEP). In this context, for R513A new refrigerant determined mathematical equations through gene expression programming. Developed mathematical models for saturation and superheated R513A refrigerant under different temperature and pressure condition compared experimental data obtained from the literature. The results have shown that the GEP model could be considered as an efficient modelling technique for the estimate data of predicting thermodynamic properties of refrigerants.

Regional variation in climate impact of grass-based biogas production: A Swedish case study

Transitioning from a fossil economy to a bio-economy will inevitably increase the demand for biomass production. One strategy to meet the demand is to re-cultivate set-aside arable land. This study investigated the climate impact and energy potential of grass-based biogas produced using fallow land in Uppsala municipality, Sweden. The assessment was performed on regional level for more than 1000 individual sites, using the agro-ecosystem model DeNitrification DeComposition (DNDC) in combination with time-dynamic life cycle assessment methodology. The results showed that the system could significantly increase biogas production within the region, which would reduce the climate impact by 9950 Mg CO2-eq per year. Compared with diesel fuel, the grass-based biogas gave a GWP reduction of 85%. However, the site-specific GWP reduction showed large spatial variability, ranging between 102 and 79% compared with diesel fuel, depending on where in the region the grass was cultivated. Two alternative scenarios were investigated, increased mineral N fertilisation and inclusion of N-fixing crops in the feedstock mixture. The highest mitigation per biogas energy produced was found for the N-fixing scenario but, because of lower yields, this scenario had lower total mitigation potential for the region than the increased fertilisation scenario. The increased fertilisation scenario had a lower climate mitigation effect per biogas energy produced, but the highest mitigation potential when the whole region was considered, because of the increased biogas production. The method applied in this study can guide land-use planning of local energy production from arable land, also for other regions.

Smart vs conventional motorways: Environmental impact assessment under realistic traffic conditions

This research aims at assessing the environmental impacts exerted by a smart motorway compared to those of a traditional motorway. The study has global policy implications: it takes into account the impacts due to the construction and maintenance of the infrastructure and the environmental effects produced by the traffic emissions, taking into account smart technologies and truck platooning regulation. Through a classical LCA approach, 1 km-long smart motorway with 2 m-high embankment was assumed as the functional unit for the analysis. A realistic traffic condition has been considered. A comparison between environmental effects produced by the use of virgin material and by Reclaimed Asphalt Pavement was made by assuming two maintenance plans. Thanks to C-ITS systems the greater safety featured by smart motorways has a significant effect on the environmental impact, compared to conventional motorways. The impact produced by safety barriers during the life cycle was also estimated. For smart motorways the impact categories GWP, POCP, AP and EP are observed to be considerably reduced in the maintenance phase of zinc-coated steel safety barriers and in those associated to traffic emissions. It must be noted that in smart motorways vehicle emissions are markedly influenced by the percentage of heavy vehicles travelling in Truck Platooning mode. The results show that concomitant use of lime stabilization and RAP leads to a significant reduction in energy consumption (up to 35%) and pollutant emissions (up to 34% of CO2) than in case of exclusive use of virgin material. The accidents reduction produce a 30% decrease of GWP, POCP, AP and EP related to safety barriers maintenance phase than the corresponding values of traditional motorway. Truck platooning mode generates GWP reduction close to 4%. The environmental advantages of a smart motorway increase progressively with the increase of AADT, platooning truck percentage and heavy vehicles percentage.

Streamlined Assessment to Assist in the Design of Internet-of-Things (IOT) Enabled Products: A Case Study of the Smart Fridge

AbstractThis paper shows how designers of IoT-enabled products can assess the environmental impacts associated with the user behaviour and the service system around the product. High-quality secondary data and a user-behaviour survey were able to highlight critical aspects of a smart fridge's design. A streamlined LCA looked at just the in-use phase of the product within 4 PSS scenarios. The system included: the effects on the food waste; grocery shopping methods; fridge door openings; and how the users interact with the smart fridge features. The results show that a smart fridge as within a PSS can reduce the impact on the environment (GWP of 21,700 kg CO2-eq within the ‘average PSS scenario’ and GWP of 23,100 kg CO2-eq for the normal fridge with ‘typical scenario’). The product's increased emissions are counteracted by the reduction in GWP due to: reduction in food waste; and shifts from brick-and-mortar grocery shopping to e-commerce. Therefore some of the critical aspects of the product's design that are most influential on the environmental impact of an IoT fridge are: the design of the web-browsing capability; and the use-by date tracking system.

Trade-off between the economic and environmental impact of different decarbonisation strategies for residential buildings

German residential multi-family buildings in the 1950s–1970s age group are a relevant case study to assess the degree of certainty in meeting climate targets for the built environment. This research evaluates the contribution of traditional strategies, and whether innovative strategies perform environmentally and economically better for this purpose. We use LCA to define a benchmark for the environmental impact, expressed as lifecycle GWP, and LCC to assess the economic impact, expressed as Internal Rate of Return (IRR). The two indicators are evaluated in a Pareto optimal method. We consider combinations of strategies for the thermal envelope, the building services, and the integration of locally available renewable energy in five existing buildings. Results show that accelerating the implementation rate of traditional strategies contributes only partially to raise the degree of certainty in reaching climate targets. For this purpose, innovative building services strategies as well as the extensive integration of local energy generation from renewable sources is required, even if the GWP reduction target of electricity from the main grid is met. The use of renewable energy has a much bigger impact on the overall GWP balance than the choice between a standard renovation and a minimal renovation of the building envelope. IRR tends to sink with GWP. We conclude that a regulated benchmark for the environmental lifecycle impact of residential building projects will help to introduce the trade-off assessment necessary to identify economically sustainable strategies that increase the level of certainty in meeting climate targets.

Retrofit of lower GWP alternative R449A into an existing R404A indirect supermarket refrigeration system

R404A is going to be phased out from most of the commercial refrigeration systems due to its high GWP value of 3943. R449A (GWP of 1282) has been proposed to replace R404A with only minor system modifications in supermarkets. This paper presents the measurements of a light retrofit replacement of R404A using R449A in a medium temperature indirect refrigeration system (secondary fluid temperature at the evaporator outlet between −9 and −4 °C). It has been demonstrated that with a slight expansion device adjustment and 4% increase of refrigerant charge, R449A can be used in this refrigeration system designed for R404A because of its suitable thermodynamic properties and acceptable maximum discharge temperature. At a secondary fluid temperature at condenser inlet of 30 °C, the COP of R449A nearly matches that of R404A (both were between 1.9 and 2.2), despite having approximately 13% lower cooling capacity. As a conclusion, attending to the GWP reduction and similar energy performance, it was demonstrated using the TEWI methodology that the use of the recently developed refrigerant R449A in these applications can reduce the total CO2 equivalent emissions of an indirect supermarket refrigeration system designed for R404A refrigerant.

온실가스 저감기술에 대한 환경전과정평가

In this study, the environmental improvement effectiveness of CCU(Carbon capture & utilization) technology is analyzed, based on LCA(Life cycle assessment) methodology. Target CCU technology is synthesis process which uses carbon dioxide as raw material and produces useful materials such as DMC(Dimethyl carbonate), methanol and etc. As a result of LCA performed, 25 g CO2 eq. of greenhouse gases is reduced during life cycle for treating 1 kg of carbon dioxide. Therefore, target CCU technology produces an effect on greenhouse gas reduction. And electricity consumption of synthesis process is the main issue of GWP results. The improvement of energy type of synthesis process is effective for GWP. 746 g CO2 eq. of greenhouse gases is reduced by changing energy type of synthesis process. As a result, life cycle GWP reduction is obtained. The scenario analysis about carbon dioxide transportation distance is performed. In case of the distance of carbon dioxide transportation is farther than 97.13 km, the amount of greenhouse gas emission during life cycle is larger than avoid and target CCU technology is ineffective for greenhouse gas reduction. Consequentially, target CCU technology is effective for greenhouse gas reduction. And the region for installing the process should consider the distance of carbon dioxide transportation.