An experimental study of an Organic Rankine Cycle utilizing HCFO-1233zd(E) as a drop-in replacement for HFC-245fa for ultra-low-grade waste heat recovery. (5th November 2020)

• Record Type: Journal Article
• Authors: Araya, Sebastian; Wemhoff, Aaron P.; Jones, Gerard F.; Fleischer, Amy S.
• Is Part Of: Applied thermal engineering. Volume 180(2020)
• Publication Date: 2020-11-05
• Subjects: Organic Rankine Cycle -- HFC-245fa -- HCFO-1233zd(E) -- Waste heat recovery -- Low GWP refrigerant; Heat engineering -- Periodicals; Heating -- Equipment and supplies -- Periodicals; Periodicals; 621.40205
• DOI: 10.1016/j.applthermaleng.2020.115757
• Languages: English
• ISSNs: 1359-4311

Abstract

Highlights: Novel lab-scale HCFO-1233zd(E) Organic Rankine Cycle testing below 90 °C. Required mass flow rate of HCFO-1233zd(E) is 21% lower than HFC-245fa at 42 °C. Evaporator heat exchange for HCFO-1233zd(E) is 17% lower than HFC-245fa at 43 °C. Both refrigerants have similar net thermal power. Peak organic Rankine cycle efficiency for HCFO-1233zd(E) is 5.0% at 85.7 °C. Abstract: The use of Organic Rankine Cycles (ORCs) for waste heat recovery can reduce energy consumption in data centers, which in turn benefits the environment through the reduction of carbon-based fuels. However, data center applications exist in the ultra-low temperature range (40 − 80℃), making efficient and economical operation challenging. The operating fluids that are viable in this temperature range are limited, so it can be a challenge to identify a suitable drop-in replacement for a proven fluid. In this study, the use of HCFO-1233zd(E) is explored to determine its suitability as a low Global Warming Potential and zero Ozone Depletion Potential alternative to the more common HFC-245fa in ultra-low temperature data center applications. This study features the first known comprehensive comparison between the alternative working fluid HCFO-1233zd(E) and HFC-245fa in a lab-scale experimental ORC under ultra-low-grade waste heat temperatures. The results of this study show that the lower HFCO-1233zd(E) saturated pressures impact the ORC operation by reducing the mass flow rate by 3–21%, thereby reducing the heat transfer across the evaporator and condenser. However, the peak thermal efficiency of the lab-scale system is seen to increase with the use of HCFO-1233zd(E) to a high of 5.0% from 4.6% with HFC-245fa. This work also identifies the minimum feasible waste heat temperature as 55 °C for a successful ORC application with both working fluids.