RESEARCH AREAS

Dynamic Simulation of Thermal Systems

Dr. Bach is interested in dynamic simulation of thermal systems, especially related to refrigerant charge and the effects thereof onto system operation (Alghamdi and Bach, 2021).

Thermal Energy Storage Integration

Dr. Bach’s research projects include integration of thermal energy storage (TES) into unitary equipment, as well as Thermal Energy Storage design and sizing using whole building simulation (Alghamdi et al., 2022).

Heat Pump System and Component Level Modifications

Dr. Bach’s research on heat pump system level modifications include vapor injected compression (Bach and Cheung, 2016; Bach, 2017, Bach et al. 2014a to e) and flash gas bypass (Bach et al. 2014b), as well as hybrid control (Bach et al. 2014a to d, and Bach et al. 2012 a/b and 2013) of the outdoor coil to reduce the impact of frosting. 

Heat Pump Defrosting Algorithm

Dr. Bach’s research on heat exchanger frosting and defrosting includes developing improved algorithms for defrosting rooftop heat pumps (AAON-OCAST AR21-071) as well as other applications. His current work there includes the development of a tunable frosting model to enable onboard optimization of defrosting controls. In the past, he evaluated adaptive vs. non-adaptive defrost controllers for a refrigeration application under various load profiles (Bach 2009 a/b), and evaluated the effect of frosting for a walk-in cooler application ()

References

Bach, C. K. (2014). Refrigerant Side Compensation for Air-side Maldistribution of Evaporators and its Effects on System Performance. PhD Thesis. Purdue University.

Bach, C. (2009a). Ermittlung des Energieeinsparpotenzials durch Regelungstechnik in Kaelteanlagen. Hochschule Karlsruhe - Technik und Wirtschaft. Diploma Thesis.

Bach (2009b). Ermittlung des Energieeinsparpotenzials durch Regelungstechnik in Kälteanlagen - Simulationsstudien und Praxisuntersuchungen. Presentation for DKV-Unterbezirksverein Karlsruhe.

Alghamdi, K., C. K. Bach, and J. D. Spitler. (2022). Water-Based Thermal Energy Storage for Heating and Air-Conditioning Applications in Residential Buildings: Review and Preliminary Study. 19th International Refrigeration and Air Conditioning Conference at Purdue, July 10 - 14, 2022. Paper 2238.

Alghamdi, K. I., Bach, C. K. (2021). Dynamic Modeling of Packaged Air Conditioner with Micro-Channel Heat Exchanger Condenser. 18th International Refrigeration and Air Conditioning Conference at Purdue. Accepted Paper #2267. 

Bach, C. K. & Cheung, H. (2016). Mapping of Vapor Injected Compressor with Consideration of Extrapolation Uncertainty. ASHRAE Winter Conference. Orlando. Paper OR-16-C042.

Bach, C. K. (2017). Vapor Injected Compression. New book section in the CRC Handbook of Thermal Engineering. CRC Press. ISBN 9781498715270.

Bach, C. K., E. A. Groll, J. E. Braun, and W. T. Horton. (2014a). Application of Two Hybrid Control Methods of Expansion Valves and Vapor Injected Compression to Heat Pumps. 11th International Energy Agency Heat Pump Conference, Montreal. Paper AM-4249223.

Bach, C. K., E. A. Groll, J. E. Braun, and W. T. Horton. (2014b). Experimental Investigation of Vapor Injected Compression for Cold Climate Heat Pumps. 15th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, July 14–17. Paper 2111.

Bach, C. K., E. A. Groll, J. E. Braun, and W. T. Horton. (2014c). Effects of Vapor Injected Compression, Hybrid Evaporator Flow Control, and other Parameters on Seasonal Energy Efficiency. 15th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, July 14–17. Paper 2675.

Bach, C. K., E. A. Groll, J. E. Braun, and W. T. Horton. (2014d). Application of Two Hybrid Control Methods of Expansion Valves and Vapor Injected Compression to Heat Pumps. 11th International Energy Agency Heat Pump Conference, Montreal. Paper AM-4249223.

Bach, C. K., E. A. Groll, J. E. Braun, and W. T. Horton. (2014e). Application of Two Hybrid Control Methods of Expansion Valves and Vapor Injected Compression to Heat Pumps. 11th International Energy Agency Heat Pump Conference, Montreal. Paper AM-4249223.

Bach, C. K., E. A. Groll, J. E. Braun, and W. T. Horton. (2016a). Dual Port Vapor Injected Compression: In-System Testing versus Test Stand Testing, and Mapping of Results. Renew Energy. 87 (1): 819-833.

Bach, C. K., E. A. Groll, J. E. Braun, and W. T. Horton. (2016b). A Non-Dimensional Mapping of a Dual-Port Vapor Injected Scroll Compressor. ASHRAE Winter Conference. Orlando. Paper OR-16-C041.

Bach, C. K., E. Groll, and J. Braun. (2012a). Application of a Hybrid Control of Expansion Valves to a 3-Ton Large Room Cooling System. 14th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, July 14–19. Paper 2123.

Bach, C. K., E. Groll, and J. Braun. (2012b). Application of a Hybrid Control of Expansion Valves to a 5-ton Domestic Heat Pump. 14th International Refrigeration and Air Conditioning Conference at Purdue, West Lafayette, IN, July 14–19. Paper 2598.

Bach, C. K., E. Groll, J. Braun, and W. T. Horton. (2013).  Application of a Hybrid Control of Expansion Valves to a Domestic Heat Pump and a Walk-in Cooler Refrigeration System. HVAC&R Research, 19 (7): 800-813.