Laboratory Evaluation of R407H for Commercial Refrigeration Applications

Recently, many types of low GWP refrigerants are being promoted to reduce global warming in the global HVAC/R market. As the optimal refrigerant for each application is different depending on application type, capacity and temperature range, and safety requirement, it is important to have diversity of refrigerant choice. Globally and in the US the commercial refrigeration industry is in a transition to refrigerants below a global warming potential of 1500 to meet regulatory requirements. A new Class A1 refrigerant blend in the R407 series was developed, R407H, to meet this requirement for commercial refrigeration applications. To evaluate the performance of the blend in medium and low temperature conditions a comparison was performed at Creative Thermal Solutions (Urbana, IL) utilizing a refrigeration laboratory. The laboratory was instrumented to ASHRAE 72 standard requirements and consists of varying capacity, VFD controlled, tandem scroll compressors, coupled with a controlled condenser and running a set of 5 cases with a combined LT load of 2.98kW and combined medium temperature load of 7.86kW. The equipment selected was standard R22/R404A equipment. The system was controlled by an Emerson E2 in combination with LabVIEW and HP Datalogging. The system was baselined with R22 and a comparison was made to R404A and R407H. As the test is ongoing, R407A and R448A final data will be avaliable during the presentation. The system was analyzed both as a nominal “Drop-In” and with minor optimizations. System effects due to glide, such as frosting, condenser and evaporator efficiency were analyzed and potential control parameters proposed and evaluated. In conclusion it was determined that R407H utilizing traditional R407 refrigerant chemistry without any additional HFO, Hydrocarbon or CO2 components is suitable as a replacement for existing R22 and R404A systems reaching expected efficiency targets while providing the benefits associated with well studied chemistries at the target GWP

The p-adic monodromy theorem in the imperfect residue field case

Let K be a complete discrete valuation field of mixed characteristic (0,p) and G_K the absolute Galois group of K. In this paper, we will prove the p-adic monodromy theorem for p-adic representations of G_K without any assumption on the residue field of K, for example the finiteness of a p-basis of the residue field of K. The main point of the proof is a construction of (phi,G_K)-module Nrig^+(V) for a de Rham representation V, which is a generalization of Pierre Colmez' Nrig^+(V). In particular, our proof is essentially different from Kazuma Morita's proof in the case when the residue field admits a finite p-basis. We also give a few applications of the p-adic monodromy theorem, which are not mentioned in the literature. First, we prove a horizontal analogue of the p-adic monodromy theorem. Secondly, we prove an equivalence of categories between the category of horizontal de Rham representations of G_K and the category of de Rham representations of an absolute Galois group of the canonical subfield of K. Finally, we compute H^1 of some p-adic representations of G_K, which is a generalization of Osamu Hyodo's results.Comment: 41 page