Suitable low Global Warming Potential (GWP) refrigerants for two-speed Heat Pumps for residential applications based on simulated performance

The next generation of heat pumps (HPs), including those intended for cold climates must transition to low-global warming potential (GWP) refrigerants to mitigate climate change. HPs must be designed to alleviate the problems of excessive discharge temperatures, low suction pressure and high-pressure ratio at low ambient conditions and insufficient heating capacity relative to the rated heating capacity. In this paper we recognize those concerns. Low global warming potential (GWP) refrigerants are screened based on the shape of their temperature-entropy (T-S) saturation boundary. Simulations of the two-stage HP with low GWP refrigerants (R32, R454B, R466A, and R452B) to replace R-410A was accomplished using the DOE/ORNL Heat Pump Design Model. Systemic inefficiency was addressed by component-level exergy analysis to refine design options. HPs with low-GWP refrigerants address issues of reducing energy consumption, lowering carbon footprint, and enabling environmental sustainability

A Comparative Life Cycle Assessment between a Metered Dose Inhaler and Electric Nebulizer

Life cycle assessment (LCA) evaluates the environmental impact of a product based on the materials and processes used to manufacture the item as well as the item’s use and disposal. The objective of this LCA was to evaluate and compare the environmental impact of a metered dose inhaler, specifically the Proventil® HFA inhaler (Merk & Co., Inc., Kenilworth, NJ, USA), and an electric nebulizer, specifically the DeVilbiss Pulmo-Aide® nebulizer (DeVilbiss, Port Washington, NY, USA). GaBi LCA software was used to model the global warming potential (GWP) of each product by using substantiated data and well-justified assumptions for the components, manufacturing, assembly, and use of both devices. The functional unit used to model each device was one dose of the active drug, albuterol sulfate. The inhaler’s GWP, 0.0972 kg CO2-eq, was greater than the nebulizer’s even when uncertain parameters were varied ±100x. During the use phase ofa the inhaler, which accounted for approximately 96% of the inhaler’s total GWP, HFA 134a is used as a propellant to deliver the drug. The total GWP for the electric nebulizer was 0.0294 kg CO2-eq assuming that the mouthpiece was cleaned in a dishwasher, while it was 0.0477 kg CO2-eq when the nebulizer mouthpiece was hand washed between uses. The GWP breakeven scenario between dishwashing and hand washing occurred when the mouthpiece accounted for 10% of the dishwasher load

A comprehensive evaluation of physical and environmental performances for wet-white leather manufacture

This paper presents the comprehensive evaluation results of physical and environmental performances for a novel wet-white (chrome-free) leather manufacturing. The tanning process is optimized as 15 wt% tannic acid (TA) combination with 4 wt% Laponite nanoclay, giving the leather with shrinkage temperature (Ts) above 86 °C. Inductively coupled plasma-atomic emission spectrometry (ICP-AES) measurements indicate that Laponite can be evenly and tightly bound within the leather matrix, which is further confirmed by scanning electron microscopy and energy dispersive X-ray (SEM-EDX) spectroscopy analysis. The resultant wet-white leathers have reasonable good physical properties that can meet the standard requirements for furniture leather without containing hazardous Cr(VI) and formaldehyde. Further life cycle assessment (LCA) studies shows that tanning process is the main contributor to environmental impact categories in the wet-white tanning process, and tannic acid is the most significant substance factor. Compared to conventional chrome tanning, the wet-white tanning process exhibits much lower abiotic depletion potential (ADP), and reduced global warming potential (GWP) and human toxicity potential (HTP) impacts due to the nature of vegetable tanning; whereas, GWP excluding biogenic carbon and energy consumption are higher owing to prolonged run time.Peer ReviewedPostprint (published version

Comparison of mini-channel condensation heat transfer for R513A and R134a

There is increased interest in emerging, low global warming potential (GWP) refrigerants due to With tthe phase out of hydrofluorocarbon (HFC) refrigerants (e.g., R134a); and the need for lower global warming potential (GWP) replacements, there are many questions that still need to be answered about replacement refrigerants, including heat transfer performance. One promising alternative to R134a (GWP = 1300) is R513A (GWP = 573), which is a non-flammable mixture comprised of 44% R134a and 56% R1234yf by weight. While this low GWPR513A refrigerant is attractive due to its lower GWP and A1 flammability rating, heat transfer data are limited. Condensation experiments were conducted for R134a and R513A in a vapor compression loop using multiport (i.e., 9 parallel channels) extruded aluminum tubes; each channel’s hydraulic diameter was 0.72 mm. Experiments covered a range of average qualities (e.g., 0.2 \u3c x \u3c 0.8) and mass fluxes (e.g., 300 \u3c G \u3c 500 kg/m2s). Heat transfer coefficients and pressure drops are reported. The heat transfer coefficients of R513A were found to be very similar to R134a. Condensation data weare compared to the condensation heat transfer coefficient correlations developed by Shah (2009) and Kim and Mudawar (2013). The MAE of the Shah correlation for R513A was 22% and 6.5% for the Kim and Mudawar (2013) correlation for R513A

Using BIM Technologies to Calculate and Visualise the Global Warming Potential of Building Materials

The built environment has a significant potential to reduce carbon emissions and raw material consumption. Digitisation processes such as Building Information Modelling (BIM) and Life Cycle Assessment (LCA) can offer solutions to improve sustainability throughout the building’s life cycle for the decarbonisation of the industry. In Ireland, the Royal Institute of Architects Ireland (RIAI) launched the 2030 Climate Challenge in response to the climate emergency. This sets out a list of targets to meet before 2030 for carbon emissions within the built environment. This research aims to investigate if the application of BIM tools can be leveraged to automate Global Warming Potential (GWP) to support design decision-making in meeting the RIAI 2030 Climate Challenge. This research focuses on the development of a validated database for building materials using the growing register of Environmental Product Data certificates (EPD) necessary for the correct calculation of GWP of building materials. This study has developed a series of workflows that can be used to automate and monitor Global Warming Potential (GWP) to assist professionals in meeting the RIAI 2025/2030 embodied carbon targets. The results demonstrated a proof of concept for automating GWP calculation via the digital building model database and, in doing so, giving the design team visual feedback, empowering them in their design decision-making

P2_6 The influence of agricultural emissions on global warming

Current estimates on the influence anthropogenic greenhouse gas emissions on global warming may have neglected the influence the agricultural emissions have, especially given the attempts to phase in biofuels in the transport industry. This paper investigates the effect emissions of nitrous oxide (N2O) may have by calculating its Global Warming Potential (GWP) over the next 100 years. However, due to a lack of data a final judgment on the effect growing more biofuels would have on climate change could not be mad

Low GWP Refrigerants for Air Conditioning and Chiller Applications

Refrigerants with low environmental impact have been developed as replacements for R410A in stationary air conditioning applications. Non-flammable and mildly flammable low global warming potential (GWP) refrigerants, have been evaluated in representative R410A residential equipment. This study discusses the performance these replacements for ambient temperatures ranging from 28oC to 46oC. Replacements for R410A and R134a are also discussed for high pressure and medium pressure chiller applications respectively. Results obtained from system simulation are discussed in detail showing the benefits of using these new fluids

Finding Global Warming Potential of Greenhouse Gases Using Cross-Sectional Infrared Spectroscopy

Infrared Spectra were taken of carbon dioxide gas to calculate Radiative Forcing (RF) through IR cross-section analysis, as a beginning of the creation of a new Physical Chemistry laboratory series that investigates Greenhouse Gases and leads students to calculate Global Warming Potential (GWP). The average RF value was 4.29 x 10-4, compared to a literature3 value of 1.4 x 10-5 W m-2. Refinement of the experimental setup must occur as next steps in this research, in order to test more gases (nitrous oxide and methane) and to calculate their GWPs

Nitrous oxide emissions in agriculture: impacts on the GHG mitigation issue

Non-Peer ReviewedNitrous oxide (N2O) is responsible for about two thirds of the emissions from agriculture. With a global warming potential (GWP) that is 310 times greater than CO2, management of N2O emissions is critical to achieve reductions. Mitigation research aimed at identifying strategies for reducing emissions from agriculture has shown that many of the “best management practices” (BMP) for achieving sustainable agricultural development in Canada also reduce GHG emissions. As such, mitigation strategies are often practices that have demonstrated economic and environmental benefits and fit within Canada’s overall sustainability objectives for the sector