PDF Publication Title:
Text from PDF Page: 137
expansion HCFC-22 refrigerated ships due to the improved system design, greater efficiency of R-717, and the use of inverters on the pumps. In fishing vessels, R-717 has already a significant presence. R-744 systems both as cascade and transcritical systems are used in this application too. Transcritical R-744 system are a good choice for small refrigeration systems and are being supplied from the commercial refrigeration sector. There is also a demand for refrigeration equipment for provision rooms operating on low GWP refrigerants such as HC-290. However, these systems are likely to require a brine circuit and will therefore have a lower overall efficiency. Cruise liners have extremely large AC systems and use large centrifugal systems now exclusively with HFC-134a (up to 10,000 t) and circulating chilled water. Systems using R-717 or flammable refrigerants are difficult to envisage without radical redesign. Indirect systems (where refrigerant is confined to a machine room and secondary coolant is distributed) are mostly used today and they could be redesigned for flammable refrigerants. Despite current concerns on GWP, a very large capacity (280,000cft) ultra-low-temp reefer ship (-50°C) was recently delivered (ULTR) designed to operate on R-404A, clearly indicating that further and more effective dissemination of information is required. 6.3.4 Railways HVAC units for passenger trains commonly use HFC-134a or R-407C as working fluids. One manufacturer has proposed R-449C as a replacement to R-407C (Zankl and Crombie, 2017). HFC-134a could be replaced with R-513A based on the studies conducted in other industry segments. The German and French railways have continued to look at air cycle systems as alternatives to vapour compression systems. In 2015, DB, a German railway company, has equipped an ICE train (Liebherr, 2015) while SNCF, the French railway company, has set up a 24-month demonstration program in a regional train (RG, 2015). Several companies have presented units with R-744 but they have not been applied in commercial projects. Flammability is a major concern in public transport; therefore flammable solutions are unlikely. 6.3.5 Energy efficiency considerations One of the challenges in the transition to lower GWP for transport refrigeration relates to the fact that some of the alternative refrigerants tend to have lower efficiency than incumbent refrigerants. For instance, R-744 is a valid non-flammable alternative in some applications, but medium to high ambient efficiency tends to be challenging for R-744 as opposed to conventional refrigerants not operating in a transcritical cycle. In a similar manner, some of the new HFO/HFC blends tend to lead to lower efficiency unless the systems are optimised for these fluids. When assessing the environmental impact of new refrigerants, both the direct and the indirect effect are relevant. The indirect effect is often dominant, and closely related to the energy consumption. For this reason, energy efficiency as well as the type of energy source used are as important, or even more important, as the GWP itself with regards to environmental impact. A detailed study on TEWI (total equivalent warming impact) and LCCP (life cycle climate performance) was presented to compare refrigerant options at different ambient temperature conditions operated in the US (Finckh et al., 2016). Figure 6-1 shows the estimated LCCP evaluation for the different replacement candidates for a climatic zone in the US. 124 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)