Wednesday, February 1, 2017: 11:00 AM-12:30 PM
HVAC&R Systems and Equipment
This session includes five papers on advances in refrigeration systems and low global warming potential refrigerants. The first paper introduces a new type of refrigerant pressure sensor, a chip capable of operating at the required temperature and pressure ranges and compatible with the fluids used in these systems. The second and third papers present promising test results on the performance characteristics and chemical stability of next generation refrigerants, as replacements for R123. The fourth paper presents the performance gains achievable in DX systems using controls that continuously adjust refrigerant charge. Finally, the fifth paper presents modeling results on the global warming impacts of four types of supermarket refrigeration systems.
1 Assessment of Next Generation Refrigerant R514A as Replacement for R123 in Centrifugal Chillers (LV-17-C085)
R123 has been used successfully as a low ODP replacement for R11 since the ban on R11’s production after December 31, 1995, imposed by the Montreal Protocol. However, the Montreal Protocol ban on use of R123 after December 31, 2019, in developed countries is becoming imminent. This paper provides a description of the environmental and thermodynamic characteristics of R514A as a replacement for R123. The thermodynamic properties of R514A result in comparable performance to R123. The performance of two centrifugal compressor-based chillers was measured in laboratory tests with R123 as a baseline and with R514A as a replacement.
2 Chemical Stability Assessments of R-514A and R-1233zd(E) (LV-17-C086)
As the phase-out date for R-123 in approaches, alternative low pressure refrigerants are being identified and qualified for use in new and existing chiller products. This paper summarizes chemical stability evaluations that were conducted in the laboratory and in operating equipment to evaluate the system chemistry of refrigerant alternatives R-514A and R-1233zd(E). Chemical stabilities of refrigerants 514A and 1233zd(E) were proven to be similar to or better than R-123, and both refrigerants have been qualified for application in a range of centrifugal compressor-based chiller products. R-1233zd(E) has higher operating pressures than R-123 and is applied in new equipment designs.
3 Continuous Tuning of Refrigerant Charge to Improve DX Equipment Performance (LV-17-C087)
This paper reports on laboratory and field investigation of the effect of refrigerant charge level on DX packaged air-conditioner electric power demand, cooling capacity, and energy efficiency. In the laboratory, numerous performance parameters were analyzed as refrigerant charge level was incrementally adjusted above and below the manufacturer nameplate charge amount at a range of operating conditions. Automated charging controls along with performance monitoring systems were installed on package units at field sites in three climate zones: 3A (temperate-humid), 3B (hot-dry), and 2A (hot-humid).
4 Modeling of Total Equivalent Global Warming Impacts of Supermarket Refrigeration Systems (LV-17-C088)
Supermarket refrigeration systems are large contributors to greenhouse gas (GHG) emissions, which impose ever-increasing and global environmental concerns. It is important to quantify the GHG emissions that occur over the lifetime of supermarket refrigeration systems, for baseline refrigerants and systems, as well as for newer, low-global warming potential (low-GWP) refrigerants and systems. A commercially available simulation tool was used to model four refrigeration systems in a large supermarket, in two locations in California. GHG emissions from direct refrigerant release and indirect emissions due to energy consumption were considered.