PDF Publication Title:
Text from PDF Page: 095
volumetric capacity either identical or in the range of ±5%, with a COP from 2 to 7% lower compared to HCFC-22. Many low-GWP HFC/HFO blends contain HFC-32 and HFO-1234yf and/or HFO-1234ze(E), and they are classified as 2L low-flammability refrigerants in ASHRAE 34. For HCFC-22, HFC alternative-blend options that are proposed show performances close to the benchmark reference. The results indicate that soft optimization could lead to performances on the level of the baseline refrigerants. Nevertheless, equipment manufacturers have to take into account in the new equipment design that all these refrigerant blends have temperature glide varying from 4 to 7 K. In addition, A2L refrigerants are designated as Class 1 by the Pressure Equipment Directive (PED) and this has to be taken into account in the design of components and equipment. Replacement lower GWP refrigerants for HFC-134a in this type of equipment include R-450A and R-513A. The HFOs are also being tested as possible replacements but the refrigerant amount is limited by the equipment safety standards. R-717 R-717 is not commonly used in these systems for cost and safety issues. However, it is used in cascade systems with R-744 in the low stage of the equipment, especially in larger commercial application needs. Research into low-charge systems is being done that could make this refrigerant more attractive in these applications. R-744 New R-744 condensing units are now commercially available in Europe and Asia. The market penetration is low at present but is expected to increase in the near future. R-744 condensing units require a double-stage design if high ambient temperatures occur frequently. Single-stage systems are designed for cold climates. The additional cost for a double-stage system is significant compared to usual HFC reference condensing units. The cost remains the main barrier for these R-744 condensing units in certain regions, but with increasing production capacity and financial incentives this barrier is expected to be overcome soon. Energy savings over HCFC-22 systems may provide incentives to use R-744. In a pilot program using R-744 condensers in 12 Indonesian pilot stores, energy savings of 20% compared to the existing older design HCFC-22 system was achieved (Santoso, 2016). Hydrocarbons Direct expansion condensing units using HC-600a or HC-290 or HC-1270 from 100 W to 10 kW (up to 1.4 kg charge) are commercially available from major manufacturers for temperatures ranging from -40°C up to 0°C. Costs for these HC-based systems can be up to 15% higher than HFC systems due to safety measures required for mitigation of risks. Due to flammability concerns, indirect condensing units using HC-290 or HC-1270 with typical refrigerant charges varying from 1 to 20 kg, are beginning to be used in Europe. The HC systems can achieve up to 30% increases in energy efficiency (Garry, 2018). Summary for condensing unit systems The replacement of R-404A is underway primarily with lower GWP and low GWP HFC and HFC/HFO blends. Many of the newer low GWP replacement refrigerants for R-404A tend to be classified as A2L for flammability and toxicity. The use of these refrigerants can be expected to grow as standards get developed and the refrigerants become more readily available. The use of HC-290 is also growing in this application as safety standards improve leak mitigation and refrigerant charge limits. R-744 trials are underway but condensing unit systems are often focus on simplicity and cost which make it a challenge for R-744 to be applied. This could change as more research and trials yield positive results. 82 2018 TOC Refrigeration, A/C and Heat Pumps Assessment ReportPDF Image | Heat Pumps Technical Options
PDF Search Title:
Heat Pumps Technical OptionsOriginal File Name Searched:
RTOC-assessment-report-2018_0.pdfDIY PDF Search: Google It | Yahoo | Bing
CO2 Organic Rankine Cycle Experimenter Platform The supercritical CO2 phase change system is both a heat pump and organic rankine cycle which can be used for those purposes and as a supercritical extractor for advanced subcritical and supercritical extraction technology. Uses include producing nanoparticles, precious metal CO2 extraction, lithium battery recycling, and other applications... More Info
Heat Pumps CO2 ORC Heat Pump System Platform More Info
CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com (Standard Web Page)