Sayyad Nazary, Ali
ORCID: https://orcid.org/0000-0002-7364-3459
(2026)
Free-Piston Heat Recovery Using Stirling and Organic Rankine Cycles.
Masters thesis, Concordia University.
Text (application/pdf)
7MBSayyad Nazary_MASc_S2026.pdf - Accepted Version Restricted to Repository staff only until 30 March 2027. Available under License Spectrum Terms of Access. |
Abstract
All energy consumed in data centers is ultimately rejected as low-temperature heat, representing
a 2016 cost of 152B dollars. Projected 2030 carbon emissions are 8000 million tons. Waste heat recovery
(WHR) allows the recovery of rejected energy, lowering both costs and emissions. The most
interesting WHR thermodynamic cycles are the Organic Rankine Cycle (ORC) and the over-looked
Stirling cycle. Both ubiquitously suffer from limitations resulting from their use of rotary devices.
ORCs traditionally use turbines, only efficient in narrow operating conditions. Stirling engines
link piston motions through a crankshaft-type mechanism, causing near sinusoidal motion and
deviations from the ideal cycle. A free-piston expander coupled to a linear generator (FPE-LG)
can be used with both Stirling and ORC engines to control the piston(s) motion, leading to a
wider operation range (ORC) or a more ideal thermodynamic path (Stirling). In this work, the
ideal velocity profile for alpha-type Stirling engines is formulated, the influence of a realistic FPE-LG
implementation (finite acceleration rate) on cycle efficiency and characteristics are examined. An
FPE-LG Stirling is compared to a sinusoidal and Rhombic-drive Stirling, and FPE-LG ORC. Time resolved, semi-analytical adiabatic Stirling models are solved. The infinite-acceleration FPE-LG
Stirling has better efficiency than Rhombic and Sinusoidal drives. The FPE-LG ORC under performs the Stirling cycles at most temperatures examined, except at very small delta-T . For a finite
acceleration FPE-LG Stirling engine, higher accelerations cause higher efficiencies up to a critical
value, beyond which the improvement is minimal. A new direction for WHR cycles is proposed.
| Divisions: | Concordia University > Gina Cody School of Engineering and Computer Science > Mechanical, Industrial and Aerospace Engineering |
|---|---|
| Item Type: | Thesis (Masters) |
| Authors: | Sayyad Nazary, Ali |
| Institution: | Concordia University |
| Degree Name: | M.A. Sc. |
| Program: | Mechanical Engineering |
| Date: | 10 March 2026 |
| Thesis Supervisor(s): | Kiyanda, C.B. |
| Keywords: | Data Center, Organic Rankine Cycle (ORC), Stirling Cycle, Free-Piston Expander (FPE), Waste Heat Recovery (WHR) |
| ID Code: | 996996 |
| Deposited By: | Ali Sayyad Nazary |
| Deposited On: | 29 Jun 2026 14:49 |
| Last Modified: | 29 Jun 2026 14:49 |
References:
[1] Z. Cao, X. Zhou, H. Hu, Z. Wang, and Y. Wen, “Toward a systematic survey for carbon neutraldata centers,” IEEE Communications Surveys & Tutorials, vol. 24, no. 2, pp. 895–936, 2022.
[2] Y. A. C¸ engel, M. A. Boles, and M. Kanoglu, ˘ Thermodynamics: An Engineering Approach,
10th ed. New York, NY, USA: McGraw-Hill, 2024.
[3] A. K. Nassir and H. A. K. Shahad, “Energy and exergy performance analysis of different
Kalina cycle configurations,” International Journal of Heat and Technology, vol. 40, no. 6,
pp. 1454–1461, Dec. 2022.
[4] Z. Li, Y. Lu, Y. Huang, G. Qian, F. Chen, X. Yu, and A. Roskilly, “Comparison study of
trilateral Rankine cycle, organic flash cycle and basic organic Rankine cycle for low-grade
heat recovery,” Energy Procedia, vol. 142, pp. 1441–1447, Dec. 2017.
[5] I. Urieli and D. M. Berchowitz, Stirling Cycle Engine Analysis. Bristol, U.K.: A. Hilger,
1984.
[6] B. Kongtragool and S. Wongwises, “A review of solar-powered Stirling engines and lowtemperature differential Stirling engines,” Renewable and Sustainable Energy Reviews, vol. 7,
no. 2, pp. 131–154, Apr. 2003.
[7] F. Alshammari, U. Muhammad, and A. Pesyridis, “Expanders for organic Rankine cycle
technology,” in Organic Rankine Cycle Technology for Heat Recovery, E. Wang, Ed. London,
U.K.: InTech, 2018.
[8] S. Emhardt, G. Tian, and J. Chew, “A review of scroll expander geometries and their performance,” Applied Thermal Engineering, vol. 141, pp. 1020–1034, Aug. 2018.
[9] V. Lemort and A. Legros, “Positive displacement expanders for organic Rankine cycle systems,” in Organic Rankine Cycle (ORC) Power Systems. Elsevier, 2017, pp. 361–396.
[10] R. Mikalsen and A. P. Roskilly, “A review of free-piston engine history and applications,”
Applied Thermal Engineering, vol. 27, no. 14–15, pp. 2339–2352, Oct. 2007.
[11] S. Douvartzides and I. Karmalis, “Working fluid selection for the organic Rankine cycle
(ORC) exhaust heat recovery of an internal combustion engine power plant,” IOP Conference
Series: Materials Science and Engineering, vol. 161, p. 012087, Nov. 2016.
[12] Z. Song, X. Zhang, and C. Eriksson, “Data center energy and cost saving evaluation,” Energy
Procedia, vol. 75, pp. 1255–1260, Aug. 2015.
[13] Ember, “Global electricity review 2024,” Ember Climate, Tech. Rep., 2024, [Online]. Available: https://ember-energy.org/latest-insights/global-electricity-review-2024/
global-electricity-trends/. Accessed: Sep. 4, 2025.
[14] A. Andrae and T. Edler, “On global electricity usage of communication technology: Trends
to 2030,” Challenges, vol. 6, no. 1, pp. 117–157, Apr. 2015.
[15] Goldman Sachs, “AI is poised to drive 160% increase in data center power
demand,” 2024, [Online]. Available: https://www.goldmansachs.com/insights/articles/
AI-poised-to-drive-160-increase-in-power-demand. Accessed: Aug. 1, 2025.
[16] International Energy Agency, “Electricity 2024: Analysis and Forecast to 2026,” International Energy Agency, Tech. Rep., 2024, [Online]. Available: https://www.iea.org/reports/
electricity-2024. Accessed: Feb. 23, 2026.
[17] D. Champier, “Thermoelectric generators: A review of applications,” Energy Conversion and
Management, vol. 140, pp. 167–181, May 2017.
[18] D. Ji, H. Cai, Z. Ye, D. Luo, G. Wu, and A. Romagnoli, “Comparison between thermoelectric
generator and organic Rankine cycle for low- to medium-temperature heat source: A technoeconomic analysis,” Sustainable Energy Technologies and Assessments, vol. 55, p. 102914,
Feb. 2023.
[19] M. K. Patterson, “The effect of data center temperature on energy efficiency,” in Proceedings of
the 11th Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic
Systems, 2008, pp. 1167–1174.
[20] V. Zare and S. M. S. Mahmoudi, “A thermodynamic comparison between organic Rankine
and Kalina cycles for waste heat recovery from the gas turbine–modular helium reactor,”
Energy, vol. 79, pp. 398–406, Jan. 2015.
[21] M. Imran, M. Usman, B.-S. Park, and D.-H. Lee, “Volumetric expanders for low-grade heat
and waste heat recovery applications,” Renewable and Sustainable Energy Reviews, vol. 57,
pp. 1090–1109, May 2016.
[22] B.-T. Liu, K.-H. Chien, and C.-C. Wang, “Effect of working fluids on organic Rankine cycle
for waste heat recovery,” Energy, vol. 29, no. 8, pp. 1207–1217, Jun. 2004.
[23] Y. P. Patel, “Optimization of free piston expander based organic Rankine cycle,” M.A.Sc.
thesis, Concordia University, Montreal, QC, Canada, Dec. 2021, [Online]. Available: https:
//spectrum.library.concordia.ca/id/eprint/990129/1/Patel%20MASc%20F2021.pdf.
[24] S. Ranieri, G. A. O. Prado, and B. D. MacDonald, “Efficiency reduction in Stirling engines
resulting from sinusoidal motion,” Energies, vol. 11, no. 11, p. 2887, 2018.
[25] S. O. Oyedepo and B. A. Fakeye, “Waste heat recovery technologies: Pathway to sustainable
energy development,” Journal of Thermal Engineering, vol. 7, no. 1, pp. 324–348, 2021.
[26] B. Donkin, A Text-Book on Gas, Oil and Air Engines, 3rd ed. London, U.K.: Charles Griffin
and Company, Limited, 1900.
[27] H. Ohman and P. Lundqvist, “Screw expanders in orc applications: Review and a new ¨
perspective,” in Proceedings of the 3rd International Seminar on ORC Power Systems (ORC
2015), 2015.
[28] C. Wang, B. Wang, M. Liu, and Z. Xing, “A review of recent research and application progress
in screw machines,” Machines, vol. 10, no. 1, p. 62, Jan. 2022.
[29] Y. Wang, L. Chen, B. Jia, and A. P. Roskilly, “Experimental study of the operation characteristics of an air-driven free-piston linear expander,” Applied Energy, vol. 195, pp. 93–99,
2017.
[30] X. Wang, F. Chen, R. Zhu, G. Yang, and C. Zhang, “A review of the design and control of
free-piston linear generator,” Energies, vol. 11, no. 8, p. 2179, 2018.
[31] C. Orrego Caicedo, “Design of a switched control system for a free-piston linear expander,”
M.A.Sc. thesis, Concordia University, Montreal, QC, Canada, Aug. 2022, [Online]. Available:
https://spectrum.library.concordia.ca/id/eprint/990898/.
[32] G. Li, H. Zhang, F. Yang, S. Song, Y. Chang, F. Yu, J. Wang, and B. Yao, “Preliminary development of a free-piston expander–linear generator for small-scale ORC waste heat recovery
system,” Energies, vol. 9, no. 8, p. 583, 2016.
[33] X. Hou, H. Zhang, F. Yu, H. Liu, F. Yang, Y. Xu, Y. Tian, and G. Li, “Free-piston expander–
linear generator used for ORC waste heat recovery system,” Applied Energy, vol. 208, pp.
1271–1283, 2017.
[34] X. Hou, H. Zhang, Y. Xu, F. Yu, T. Zhao, Y. Tian, Y. Yang, and R. Zhao, “External load
resistance effect on the free-piston expander–linear generator for ORC waste heat recovery
system,” Applied Energy, vol. 212, pp. 1252–1261, 2018.
[35] Y. Xu, L. Tong, H. Zhang, X. Hou, F. Yang, F. Yu, Y. Yang, R. Liu, Y. Tian, and T. Zhao,
“Experimental and simulation study of a free-piston expander–linear generator for small-scale
ORC,” Energy, vol. 161, pp. 776–791, 2018.
[36] Y. Tian, H. Zhang, J. Li, X. Hou, T. Zhao, F. Yang, Y. Xu, and X. Wang, “Development and
validation of a single-piston free-piston expander–linear generator for a small-scale ORC,”
Energy, vol. 161, pp. 809–820, 2018.
[37] B. J. G. De La Bat, R. T. Dobson, T. M. Harms, and A. J. Bell, “Simulation, manufacture and
experimental validation of a novel single-acting free-piston Stirling engine electric generator,”
Applied Energy, vol. 263, p. 114585, 2020.
[38] J. Bao and L. Zhao, “A review of working fluid and expander selections for ORC,” Renewable
and Sustainable Energy Reviews, vol. 24, pp. 325–342, 2013.
[39] M. J. Molina and F. S. Rowland, “Stratospheric sink for chlorofluoromethanes: chlorine
atom-catalysed destruction of ozone,” Nature, vol. 249, no. 5460, pp. 810–812, 1974.
[40] S. Benhadid-Dib and A. Benzaoui, “Refrigerants and their environmental impact: substitution
of HCFC and HFC. Search for an adequate refrigerant,” Energy Procedia, vol. 18, pp. 807–
816, 2012.
[41] R. W. James and T. C. Welch, “Refrigeration and heat-pump systems,” in Air Conditioning
System Design. Elsevier, 2017, pp. 167–189.
[42] G. Shu, Y. Gao, H. Tian, H. Wei, and X. Liang, “Study of mixtures based on hydrocarbons
used in ORC for engine waste heat recovery,” Energy, vol. 74, pp. 428–438, 2014.
[43] I. H. Bell, J. Wronski, S. Quoilin, and V. Lemort, “Pure and pseudo-pure fluid thermophysical property evaluation and the open-source thermophysical property library CoolProp,”
Industrial & Engineering Chemistry Research, vol. 53, no. 6, pp. 2498–2508, 2014.
[44] “Pipes, tubes, and fittings,” in ASHRAE Handbook: HVAC Systems and Equipment. Atlanta,
GA, USA: ASHRAE, 2012, ch. 46.
[45] L. G. Thieme and R. C. J. Tew, “Baseline performance of the GPU-3 Stirling engine,” NASA
Lewis Research Center, Cleveland, OH, USA, Tech. Rep. NASA-TM-79038, Nov. 1978,
presented at Highway Vehicle Systems Contractors Coordination Meeting, Dearborn, MI,
USA, Oct. 17–20, 1978.
[46] D. Erol, H. Yaman, and B. Dogan, “A review of the development of the rhombic drive ˘
mechanism used in Stirling engines,” Renewable and Sustainable Energy Reviews, vol. 78,
pp. 1044–1067, 2017.
[47] ASHRAE, “Halocarbon refrigeration systems,” in ASHRAE Handbook—Refrigeration. Atlanta, GA, USA: ASHRAE, 2014, ch. 1.
Repository Staff Only: item control page


Download Statistics
Download Statistics