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Alpharetta, GA, United States

Bradshaw C.R.,Torad Engineering | Groll E.A.,Purdue University
International Journal of Refrigeration | Year: 2013

A comprehensive simulation model of a novel rotating spool compressor is presented. The spool compressor provides a new rotary compression mechanism with easily manufactured components. A detailed analytical geometry model of the spool compressor is presented, which includes the geometry of the vane. This geometry model is included in an overall comprehensive compressor model that includes sub-models for friction, leakage, and heat transfer. The results of the comprehensive model were validated using experimental data from a prototype compressor. The prototype compressor has an overall displacement of 23.9 cm 3, and was operated using R410A as the working fluid. The model predicts the volumetric efficiency, discharge temperature, and shaft power of the prototype compressor to within 3.13% MAE, 16.5 K and -13.2 W average deviation, respectively. The trends and spread in the data indicate that additional effort should be focused on the operation of the active sealing elements within the compressor.

Bradshaw C.R.,Torad Engineering | Groll E.A.,Purdue University | Garimella S.V.,Purdue University
International Journal of Refrigeration | Year: 2013

A comprehensive model of a linear compressor for electronics cooling was previously presented by Bradshaw et al. (2011) then enhanced and used for a sensitivity analysis of the leakage gap, eccentricity, and piston geometry by Bradshaw et al. (2013). The current work utilizes the previously developed model to explore the energy recovery characteristics of a linear compressor as compared to those of a reciprocating compressor. The impact of dead (clearance) volume on both a linear and reciprocating compressor is analyzed. In contrast to a reciprocating compressor the overall isentropic efficiency of the linear compressor remains relatively unaffected by an increase in dead volume up to a certain point. This behavior is attributed to the ability of the linear compressor to recapture the energy of the compressed gas during the expansion process. This characteristic behavior allows a linear compressor to be used for efficient capacity control from roughly 35-100%.

Bradshaw C.R.,Torad Engineering | Kemp G.,Torad Engineering | Orosz J.,Torad Engineering | Groll E.A.,Purdue University
Applied Thermal Engineering | Year: 2016

A rotating spool compressor is a new compressor technology that was recently introduced by Kemp et al. in 2008. To accelerate the development of the technology, a breakdown of the key losses within the 5th generation device is presented. The losses include indicated losses associated with leakage and over/under compression due to valves and porting. These losses are obtained using high-speed pressure measurements to obtain an indicator diagram of the 5th generation device. Additionally, frictional losses associated with the key sealing elements and moving components are calculated. An experimental validation of the spool seal friction sub-model is presented. All of these losses are combined into Pareto of losses for the 5th generation spool compressor. This Pareto identified the spool seals, compression and discharge flow losses, and the friction of the Top Dead Center interface as losses to be addressed in future designs. Using this information efforts to improve these components were integrated into a 6th generation spool compressor. This generation recorded an overall isentropic efficiency of over 80% for a net improvement of nearly 15 percentage points over the 5th generation spool compressor. © 2015 Elsevier Ltd. All rights reserved.

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