Late Noachian development of the Coprates rise, Mars

The Coprates rise forms a 900 km long, north to northeast trending ridge south of Coprates Chasma between long. 56 and 60 degs. Radar and stereo photogrammetric data indicate that the rise is 2 to 4 km above a neighboring trough to the east. The break in slope between the rise and this trough is well defined topographically and in Viking images. In turn, the trough is bordered to the to the east at long. 52 deg by a much gentler rise. West of the Coprates rise, the terrain dips about 0.2 deg to roughly long. 75 deg. The rise and flanking highs were previously interpreted to be tilted fault blocks formed by either Tharsis tectonism or an ancient impact. Results are now reported of a preliminary geologic study that documents Late Noachian growth of the Coprates rise as a asymmetric fold. More comprehensive work will lead to a mechanical analysis of the kinematic development of the rise. It is concluded that the Coprate rise formed during the Late Noachian by 2 to 4 km of asymmetric uplift (steeper on its east flank). The timing is inconsistent with an origin by an early impact, but it coincides in time with early Tharsis centered radial faulting at Syria Planum

Behavior of R410A Low GWP Alternative Refrigerants DR-55, DR-5A, and R32 in the Components of a 4-RT RTU

Concerns about the impact on the environment of the refrigerants used in HVAC&R equipment are driving the development of alternative refrigerants with lower global warming potentials (GWPs). This paper reports the performance of DR-55 (now designated as R452B), DR-5A (now designated as R454B), and R32 in comparison to R410A at the component level from tests run on a 4 RT (14 kW) commercial unitary rooftop heat pump. Overall unit performance was previously reported (Schultz and Kujak, 2016), showing DR-55 and DR-5A to be design-compatible replacement candidates for R410A. This paper further confirms this by comparing performance at the compressor, evaporator, and condenser component level

Kenneth Shultz CD Summer 2010

Supports faculty to redesign or develop a course in ways that implement high-impact, evidence-based, and/or innovative teaching strategies to improve student learning

Performance of R410A and R22 Low GWP Alternative Refrigerants at Elevated Ambient Temperatures

Growing concerns about the impact on the environment of the refrigerants used in HVAC&R equipment are driving development and evaluation of alternative refrigerants with lower global warming potentials (GWPs). The Air Conditioning, Heating, and Refrigeration Institute (AHRI) recently coordinated the Low-GWP Alternative Evaluation Program (AREP) in which commercial, university, and government laboratories ran tests of a range of alternative refrigerants in a variety of HVAC&R products. This paper will report the performance of an ~4.4 RT air-cooled water chiller/heat pump run with a number of lower GWP alternative refrigerants. Tests were first run with a compressor designed for R410A-like pressures. The refrigerants tested include R410A (baseline) and R32, along with blends labeled DR-5, DR-4, L-41a, L-41b, ARM-70a, ARM-32a, and HPR1D. The compressor was then replaced with one designed for R22-like pressures. The refrigerants tested include R22 (baseline) along with blends labeled DR-4, DR-7, ARM-32a, L-20, LTR4X, and LTR6A. The blends contain R32, R1234yf, R1234ze(E), R134a, R152a, R125, and R744 (CO2) in various compositions. The results of this project have been reported previously for performance measured at the nominal operating condition of 7.2°C (45°F) leaving chiller water temperature and 35°C (95°F) air temperature (Schultz and Kujak, 2012, 2013a, 2013b; Schultz, 2014). In this paper, performance over an extended range of air temperatures from 25°C to 45°C (77°F to 113°F) will be reported and compared to a simple thermodynamic cycle model. As already reported, the predictions of the thermodynamic cycle model and measured performance are in good agreement at the nominal operating condition. However, some deviations were observed between the measured and modeled performance for air temperatures away from the nominal condition. In particular, the predicted performance benefits of some refrigerants were not observed at elevated air temperatures. On the other hand, none of the alternative refrigerants performed significantly worse than R410A at elevated air temperatures. These discrepancies indicate there are factors that need to be accounted for other than the thermodynamic properties of the refrigerants. These factors will be discussed here. Schultz and Kujak, 2012, “TEST REPORT #1?–?System Drop-in Test of R-410A Alternative Fluids (ARM-32a, ARM-70a, DR-5, HPR1D, L-41a, L-41b, and R-32) in a 5-RT Air-Cooled Water Chiller (Cooling Mode)”, AHRI Low-GWP Alternative Refrigerants Evaluation Program website, http://www.ahrinet.org/ahri+low_gwp+alternative+refrigerants+evaluation+program.aspx Schultz and Kujak, 2013a, “TEST REPORT #6?–?System Drop-in Tests of R-22 Alternative Fluids (ARM-32a, DR-7, L-20, LTR4X, LTR6A, and D52Y) in a 5-RT Air-Cooled Water Chiller (Cooling Mode)”, AHRI Low-GWP Alternative Refrigerants Evaluation Program website, http://www.ahrinet.org/ahri+low_gwp+alternative+refrigerants+evaluation+program.aspx Schultz and Kujak, 2013b, “Comparative performance of low GWP alternate refrigerants for R410A and R22 in a small air-cooled chiller”, Proceedings of ICCR3013 – 5th International Conference on Cryogenics and Refrigeration, 06-09 Apr 2013, Hangzhou, China, Paper ID B-4-09. Schultz, 2014, “Performance of R410A and R22 Alternative Lower GWP Refrigerants in a Small (~5 RT) Water Chiller”, presented at the ASHRAE Winter Conference, 19-22 Jan 2014, New York City, Conference Paper NY-14-C066

The Effects of JIT on the Development of Productivity Norms

Low inventory, or just-in-time (JIT) manufacturing systems, enjoy increasing application worldwide, yet the behavioral effects of such systems remain largely unexplored. Operations Research (OR) models of low inventory systems typically make a simplifying assumption that individual worker processing times are independent random variables. This leads to predictions that low-inventory systems will exhibit production interruptions. Yet empirical results suggest that low-inventory systems do not exhibit the predicted productivity losses. This paper develops a model integrating feedback, goal-setting, group cohesiveness, task norms, and peer pressure to predict how individual behavior may adjust to alleviate production interruptions in low-inventory systems. In doing so we integrate previous research on the development of task norms. Findings suggest that low-inventory systems induce individual and group responses that cause behavioral changes that mitigate production interruptions

Compositional Fractionation Studies of R410A Alternative R452B or DR55 and Their Impact on Flammability Behavior and Safety Implications

Today air conditioning product and applications designers, as a result of climate change contribution concerns for high direct global warming potential (GWP) refrigerants, are being asked to consider lower GWP refrigerants with various degrees of flammability. In recent year, the HVACR industry has been actively investigating the safety of flammable refrigerants by determining their risks, potential occurrences and severity of events. Today R410A is used to cover most air conditioning applications and all lower GWP alternatives presented to date have some degree of flammability with most being ASHRAE 34 flammability class 2L.  A novel R410A alternative refrigerant blend, R452B or DR55, has recently been studied in a 4 ton RTU to determine the potential for compositional fractionation in various modes of operation. In addition, the ASHRAE flammability process needed to classify refrigerant flammability and flammability classification data for R452B will be presented in this paper. The unit compositional data and the ASHRAE classification process and data will be compared and contrasted to show differences in potential flammability interpretations and design safety implications

Novel Reduced GWP Refrigerant Compositions To Replace R-134a in Stationary Air-conditioning and Refrigeration

Hydrofluorocarbons (HFCs) have replaced chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) as non-ozone depleting fluids in many applications, including as refrigerants, solvents, aerosols, and blowing agents for insulating foams. However, some HFCs have relatively high Global Warming Potential (GWP) and are coming under closer scrutiny due to the increasing concern over global climate change. The focus now is on the search for the next generation of environmentally sustainable working fluids with negligible direct environmental impact in terms of both ozone depletion and global warming potential. Development of low-GWP options should be balanced with respect to safety, performance, ease of use, and energy efficiency. Indeed, greenhouse gas emissions come not only from direct emissions but also largely from indirect sources based on energy consumption. It is therefore important that energy efficiency remain a primary consideration when implementing low-GWP solutions, as replacing a high-GWP fluid with a lower GWP, but less efficient option may actually increase greenhouse gas emissions, thereby degrading the overall Life Cycle Climate Performance (LCCP). This paper introduces a novel low GWP refrigerant composition to replace R-134a. Thermodynamic properties as well as theoretical and experimental evaluation of this refrigerant is being discussed. Results are compared to baselin