scholarly journals Theoretical Global Warming Impact Evaluation of Medium and High Temperature Heat Pumps Using Low GWP Refrigerants

2021 ◽  
Vol 11 (15) ◽  
pp. 7123
Author(s):  
Morteza Ghanbarpour ◽  
Adrián Mota-Babiloni ◽  
Bassam E. Badran ◽  
Rahmatollah Khodabandeh
Keyword(s):  
Global Warming ◽  
High Temperature ◽  
Emission Factor ◽  
Impact Analysis ◽  
Coefficient Of Performance ◽  
Alternative Refrigerants ◽  
Medium Temperature ◽  
Global Warming Impact ◽  
Heating Capacity ◽  
Temperature Applications

This study provides a global warming impact analysis of environmentally friendly refrigerants used as replacements for R134a and R245fa. R290, R1234yf, R1234ze(E), R513A and R450A are considered as refrigerants to replace R134a in medium temperature applications. For R245fa, there are five alternative refrigerants, R1224yd(Z), R600, R1336mzz(Z), R1233zd(E) and R1234ze(Z), which are selected for high-temperature applications. The analysis is done considering the emission factors in Brazil, Sweden, Canada and Poland. In Sweden and Brazil, the total equivalent warming impact per heating capacity of R134a is higher than its alternative refrigerants in medium temperature application, although R134a exhibits a higher coefficient of performance than its alternatives. In high-temperature applications, R1336mzz(Z) has the lowest total equivalent warming impact per heating capacity due to its higher coefficient of performance than other tested refrigerants. The highest total equivalent warming impact per heating capacity belongs to R245fa in all countries except in Poland, where R600 exhibits a higher value due to its lower coefficient of performance and the relatively higher emission factor in Poland compared to other selected countries. These results revealed that in addition to the global warming potential, the emission factor associated with the sources of electricity generation has a crucial impact on indirect emissions.

scholarly journals Treatments of Magnesium Slag to Recycle Waste from Pidgeon Process

2011 ◽  
Vol 418-420 ◽  
pp. 1657-1667 ◽  
Author(s):  
Feng Lan Han ◽  
Qi Xing Yang ◽  
Lan Er Wu ◽  
Sheng Wei Guo
Keyword(s):  
Global Warming ◽  
High Temperature ◽  
Natural Resources ◽  
Building Materials ◽  
Volume Stability ◽  
Global Warming Impact ◽  
Slag Powder ◽  
Magnesium Production ◽  
Higher Temperature ◽  
Pidgeon Process

Magnesium slag powder from a local magnesium plant was treated to improve the volume stability for its application as building materials. The slag was mixed with borates, pressed into briquettes, and then sintered at high temperature. SEM studies show that at the higher temperature Ca2SiO4polymorphs were stabilized by Na and B ions in the added borates. The free MgO content in the slag was also decreased by the sintering treatment. The slag powder, after mixing with 0.4-0.6% of borates and sintered at 1200°C in 5-6 hours, has become volume stable aggregates. It is then possible to use the treated slag in constructions, saving valuable natural resources and decreasing the global warming impact from magnesium production via Pidgeon process.

Experimental studies on direct expansion solar thermal heat pump systems using R430A as a substitute to R134a

2021 ◽  
pp. 095440892110209
Author(s):  
M Mohanraj ◽  
I M Kartheheyan
Keyword(s):  
Global Warming ◽  
Energy Consumption ◽  
Heat Pump ◽  
Energy Performance ◽  
Solar Thermal ◽  
Coefficient Of Performance ◽  
Direct Expansion ◽  
Pump System ◽  
Discharge Temperature ◽  
Heating Capacity

The use of halogen-based refrigerants in heat pump applications is restricted because of their high global warming potential (GWP). Therefore, it is necessary to identify a low GWP substitute for heat pump applications. This article presents the energy performance of a direct expansion solar thermal heat pump system (DXSTHPS) using R430A as an environmentally friendly substitute to phase out R134a. The effects of ambient parameters on compressor discharge temperature, compressor energy consumption, condenser heating capacity and coefficient of performance (COP) of a DXSTHPS using R134a and R430A are estimated and compared. Moreover, the total equivalent global warming impacts (TEGWI) of a DXSTHPS using R134a and R430A are evaluated. The results showed that the R430A has 0.7–1.9% lower compressor energy consumption than R134a. The condenser heating capacity and COP of a DXSTHPS using R430A are higher than R134a by 4.6–8.7% and 5.1–10.2%, respectively. The compressor discharge temperature observed in a DXSTHPS using R430A is 5.8 °C higher than R134a. The lubricant physical properties are retained at higher compressor operating temperatures, ensuring compressor reliability. The DXSTHPS using R430A has 4.2–12.9% lower TEGWI due to its lower GWP with lower compressor energy consumption than R134a.

scholarly journals Multi-Model Ensemble Projection and Global Warming Impact Analysis on SST Change of Ise Bay

2013 ◽  
Vol 69 (2) ◽  
pp. I_1286-I_1290
Author(s):  
Yasushi SUZUKI ◽  
Yoshinobu SATO ◽  
Motohiro HONMA ◽  
Yuri MICHIHIRO ◽  
Sergey M. Varlamov
Keyword(s):  
Global Warming ◽  
Impact Analysis ◽  
Model Ensemble ◽  
Global Warming Impact ◽  
Ise Bay

scholarly journals Energy and Thermal Conductivity Assessment of Dimethyl-Ether and its Azeotropic Mixtures as Alternative Low Global Warming Potential Refrigerants in a Refrigeration System

2021 ◽  
Vol 25 (1) ◽  
pp. 12-28
Author(s):  
Bukola Olalekan Bolaji ◽  
Olatunde Ajani Oyelaran ◽  
Israel Olutunji Abiala ◽  
Tunde Oluwatoyin Ogundana ◽  
Semiu Taiwo Amosun
Keyword(s):  
Thermal Conductivity ◽  
Global Warming ◽  
Dimethyl Ether ◽  
Pressure Ratio ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Refrigeration System ◽  
Environmental Benefit ◽  
Alternative Refrigerants ◽  
Azeotropic Mixtures

Abstract Substituting Hydrofluorocarbons with natural refrigerants in domestic refrigerators will significantly reduce the direct contributions of fluorinated gases to global warming which will be of great environmental benefit. In this study, the performances of dimethyl-ether (RE170) and its azeotropic mixtures (R510A and R511A) in a refrigeration system were assessed theoretically and compare with that of conventional refrigerant. The study revealed that the three investigated alternative refrigerants exhibited significantly good heat transfer characteristics, low pressure ratio, high latent heat in the liquid phase which resulted in their high thermal conductivity and Volumetric Cooling Capacity (VCC). The thermal conductivity of the refrigerants reduces while the evaporating temperature rises and the value obtained for RE170 was the highest among the four refrigerants studied. The Coefficient of Performance (COP) for RE170, R510A and R511A were higher than that of R134a by 6.20, 10.06 and 3.02 % respectively while their power consumptions per ton of refrigeration were lower than that of R134a by 6.99, 11.04 and 1.47 % respectively. In conclusion, dimethyl-ether and its azeotropic mixtures performed better than R134a in that they have higher thermal conductivity, refrigerating effect, VCC, COP, lower power consumption per ton of refrigeration and hence, they can be considered as suitable replacements for R134a in domestic refrigerator.

scholarly journals Effect of long anther dehiscence on seed set at high temperatures during flowering in rice (Oryza sativa L.)

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Tsutomu Matsui ◽  
Toshihiro Hasegawa
Keyword(s):  
Global Warming ◽  
High Temperature ◽  
High Temperatures ◽  
Seed Set ◽  
Oryza Sativa L ◽  
Quantitative Information ◽  
Temperature Tolerance ◽  
Anther Dehiscence ◽  
Substitution Lines ◽  
Global Warming Impact

AbstractCountermeasures that can mitigate the global warming impact on rice production are needed. The large dehiscence of anther for pollen dispersal is one trait that shows tolerance of seed set to high temperatures under the global warming. The aim of this study is to determine the effect of long anther dehiscence on high temperature tolerance. Seven chromosome segment substitution lines and the seed parent with the different dehiscence lengths were subjected to high daytime temperatures. Elongation of dehiscence formed at the base of anther (BDL) by 100 µm mitigated the occurrence of high temperature induced sterility by 20% and improved tolerance to the high temperature by 0.66 °C. Relationship between the seed set and BDL was well explained by pollination, showing that quantitative information provided in the present experiment is reliable. The information is expected to be used in estimation of global warming impact and making countermeasures for it.

Microstructural characterization of a rapidly solidified Al-Fe-V-Si alloy for elevated temperature applications

1988 ◽  
Vol 46 ◽  
pp. 550-551
Author(s):  
R. E. Franck ◽  
J. A. Hawk ◽  
G. J. Shiflet
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Grain Growth ◽  
Volume Fraction ◽  
Microstructural Characterization ◽  
Second Phase ◽  
Microstructural Stability ◽  
Elevated Temperature Strength ◽  
Temperature Applications

Rapid solidification processing (RSP) is one method of producing high strength aluminum alloys for elevated temperature applications. Allied-Signal, Inc. has produced an Al-12.4 Fe-1.2 V-2.3 Si (composition in wt pct) alloy which possesses good microstructural stability up to 425°C. This alloy contains a high volume fraction (37 v/o) of fine nearly spherical, α-Al12(Fe, V)3Si dispersoids. The improved elevated temperature strength and stability of this alloy is due to the slower dispersoid coarsening rate of the silicide particles. Additionally, the high v/o of second phase particles should inhibit recrystallization and grain growth, and thus reduce any loss in strength due to long term, high temperature annealing.The focus of this research is to investigate microstructural changes induced by long term, high temperature static annealing heat-treatments. Annealing treatments for up to 1000 hours were carried out on this alloy at 500°C, 550°C and 600°C. Particle coarsening and/or recrystallization and grain growth would be accelerated in these temperature regimes.

The Potential of Photoelectrochemical Carbon Sinks

2018 ◽  
Author(s):  
Matthias May ◽  
Kira Rehfeld
Keyword(s):  
Global Warming ◽  
High Temperature ◽  
Greenhouse Gas ◽  
Large Scale ◽  
High Efficiency ◽  
Carbon Sink ◽  
Solar Fuels ◽  
Negative Emissions ◽  
Viable Approach ◽  
Low Sensitivity

Greenhouse gas emissions must be cut to limit global warming to 1.5-2C above preindustrial levels. Yet the rate of decarbonisation is currently too low to achieve this. Policy-relevant scenarios therefore rely on the permanent removal of CO<sub>2</sub> from the atmosphere. However, none of the envisaged technologies has demonstrated scalability to the decarbonization targets for the year 2050. In this analysis, we show that artificial photosynthesis for CO<sub>2</sub> reduction may deliver an efficient large-scale carbon sink. This technology is mainly developed towards solar fuels and its potential for negative emissions has been largely overlooked. With high efficiency and low sensitivity to high temperature and illumination conditions, it could, if developed towards a mature technology, present a viable approach to fill the gap in the negative emissions budget.<br>

The Potential of Photoelectrochemical Carbon Sinks

2018 ◽  
Author(s):  
Matthias May ◽  
Kira Rehfeld
Keyword(s):  
Global Warming ◽  
High Temperature ◽  
Greenhouse Gas ◽  
Large Scale ◽  
High Efficiency ◽  
Carbon Sink ◽  
Solar Fuels ◽  
Negative Emissions ◽  
Viable Approach ◽  
Low Sensitivity

Greenhouse gas emissions must be cut to limit global warming to 1.5-2C above preindustrial levels. Yet the rate of decarbonisation is currently too low to achieve this. Policy-relevant scenarios therefore rely on the permanent removal of CO<sub>2</sub> from the atmosphere. However, none of the envisaged technologies has demonstrated scalability to the decarbonization targets for the year 2050. In this analysis, we show that artificial photosynthesis for CO<sub>2</sub> reduction may deliver an efficient large-scale carbon sink. This technology is mainly developed towards solar fuels and its potential for negative emissions has been largely overlooked. With high efficiency and low sensitivity to high temperature and illumination conditions, it could, if developed towards a mature technology, present a viable approach to fill the gap in the negative emissions budget.<br>

FLYLITE ZRE-1

Alloy Digest ◽  
1952 ◽  
Vol 1 (2) ◽  
Keyword(s):  
Compressive Strength ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Base Alloy ◽  
Heat Treating ◽  
Jet Engine ◽  
Temperature Performance ◽  
Engine Components ◽  
Temperature Applications

Abstract Flylite ZRE-1 is a creep resistant magnesium-base alloy primarily designed for jet engine components and other high temperature applications. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and compressive strength as well as creep. It also includes information on high temperature performance as well as casting, heat treating, machining, and joining. Filing Code: Mg-2. Producer or source: Howard Foundry Company.

Sign in / Sign up

Export Citation Format

Share Document