Dr Yongjun SUNB.Eng, M.Eng, PhD
Associate Professor

Contact InformationOffice:MMW-5443
Phone:+(852)-3442-2672
Fax:+(852)-3442-9716
Email:yongjsun@cityu.edu.hk


Research Interests Zero energy building (ZEB) system design and control
Coordinated demand response
HVAC optimal and robust control
Renewable energy application
Building energy management

Dr. Sun obtained his bachelor and master degrees in thermal energy and power engineering from Xi’an Jiaotong University (XJTU) and refrigeration and cryogenics engineering from Huazhong University of Science and Technology (HUST) in 2003 and 2006, respectively. Dr. Sun received his PhD degree in building services engineering from the Hong Kong Polytechnic University in 2010. Before he joined City University of Hong Kong, Dr. Sun was a postdoctoral research fellow in the Hong Kong Polytechnic University. Dr. Sun’s current research interests include zero energy building (ZEB) system design and control, coordinated demand response, HVAC optimal and robust control, renewable energy application and building energy management.
PhD and Postdoc OpportunitiesDr. Sun is currently looking for PhD candidates and post-docs who are interested in the following aspects. You are highly encouraged to send your CVs to yongjsun@cityu.edu.hk if interested.
Data mining for building energy management
A postdoc position will be provided with a highly competitive salary. The applicant should have a strong track record in data mining. The applicant is expected to apply the data mining technologies to explore the still unknown information and knowledge from massive operation data for design and control optimizations at various levels.

Liquid based cooling for data centers
A postdoc position will be provided with a highly competitive salary. The applicant should have a strong track record in liquid-based cooling of data centers. Based on a real immersion cooling system, the applicant is expected to develop novel system design and control optimizations for improved energy efficiency and cost effectiveness.

Net-zero energy buildings
Both a PhD student and a postdoc are needed in this field. The PhD candidate should have the background of building engineering. For a PhD candidate with high competence, Dr. Sun will recommend him/her for the Hong Kong PhD fellowship scheme. The postdoc position will be provided with a highly competitive salary. The postdoc applicant should have a strong track record in one or more perspectives of renewable energy, energy storage and grid interaction, etc. The applicant is expected to develop novel design and control methods to improve renewable utilization at city/region scale.

Thermoelectric device and system design optimizations
A postdoc position will be provided with a highly competitive salary. The applicant should have a strong track record in thermoelectric and its applications. The applicant is expected to develop novel device and system design optimizations to promote their practical applications.
SCI Publications P. Huang, Y.J. Sun*. 2019. A robust control of nZEBs for performance optimization at cluster level under demand prediction uncertainty, Renewable Energy, 134, 215-227.
P. Huang, Y.J. Sun*. 2019. A clustering based grouping method of nearly zero energy buildings for performance improvements, Applied Energy, 235, 43-55.
C. Fan, G.S. Huang, Y.J. Sun*. 2018. A Collaborative Control Optimization of Grid-connected Net Zero Energy Buildings for Performance Improvements at Building Group Level, Energy, 164, 536-549.
P. Huang, G.S. Huang, Y.J. Sun*. 2018. A robust design of nearly zero energy building systems considering performance degradation and maintenance, Energy, 163, 905-919.
S. Zhang, Y.J. Sun, Y. Cheng, J. Lin*. 2018. Response-Surface-Model-Based System Sizing for Nearly/Net Zero Energy Buildings under Uncertainty, Applied Energy, 228, 1020-1031.
P. Huang, H.J. Wu, G.S. Huang, Y.J. Sun*. 2018. A top-down control method of nZEBs for performance optimization at nZEB-cluster-level, Energy, 159, 891-904.
P. Huang, G. Augenbroe, G.S. Huang*, Y.J. Sun. 2018. Investigation of maximum cooling loss in piping network using Bayesian Markov chain Monte Carlo method, Journal of Building Performance Simulation, 12, 117-132.
C. Fan, Y.J Sun*, K. Shan, F. Xiao, J.Y. Wang. 2018. Discovering Gradual Patterns in Building Operations for Improving Building Energy Efficiency, Applied Energy, 224, 2018, 116-123.
J.Q. Wang, Q.S. Jia, G.S. Huang*, Y.J. Sun. 2018. Event-driven optimal control of central air-conditioning systems: Event-space establishment, Science and Technology for the Built Environment, 0, 1-11
P. Huang, G.S. Huang, Y.J. Sun*, 2018, Uncertainty-based life-cycle analysis of near-zero energy buildings for performance improvements, Applied Energy, 213, 486-498
Y.J. Sun, G.S. Huang, X.H. Xu*, Alvin Lai, 2018, Building-group-level Performance Evaluations of Net Zero Energy Buildings with Non-collaborative Controls, Applied Energy, 212, 565-576.
J.Y. Chen, Y.J. Sun*, 2017, A New Multiplexed Optimization with Enhanced Performance for Complex Air Conditioning Systems, Energy and Buildings, 156, 85-95.
Z.(Jerry) Yu, B. Hu, Y.J. Sun*, A.b. Li, J. Li, G.J. Zhang, 2017, Standby Energy Use and Saving Potentials Associated with Occupant Behavior of Chinese Rural homes, Energy and Buildings, 154, 295-304.
A.B. Li, Y.J. Sun, X.H. Xu*, 2017, Development of a Simplified Resistance and Capacitance (RC)-network Model for Pipe-embedded Concrete Radiant Floors, Energy and Buildings, 150, 353-375
Y Yao, Y.J. Sun, D.F. Sun, C. Sang, M. Sun, L.M. Shen, H.X. Chen, 2017, Optimization Design and Experimental Study of Thermoelectric Humidifier, Applied Thermal Engineering, 123, 820–829
L.Q. Diao, Y.J. Sun, Z. Chen, J.Y. Chen*, 2017, Modeling energy consumption in residential buildings: A bottom-up analysis based on occupant behavior pattern clustering and stochastic simulation, Energy and Buildings, 147, 47–66
Y.J. Sun, G.S. Huang*, 2017, Recent Developments in HVAC System Control and Building Demand Management, Springer, DOI: 10.1007/s40518-017-0064-6
J.Q. Wang, G.S. Huang*, Y.J. Sun, X.P. Liu, 2016, Event-driven optimization of complex HVAC systems, Energy and Buildings, 133, 79-87
Z. Yu, J.Y. Chen, Y.J. Sun*, G.Q. Zhang, 2016, A GA-based System Sizing Method for Net-Zero Energy Buildings Considering Multi-criteria Performance Requirements under Parameter Uncertainties, Energy and Buildings, 129, 524-534
L.M. Shen, X.W. Pu, Y.J. Sun*, J.D. Chen, 2016, A study on thermoelectric technology application in net zero energy buildings, Energy, 113, 9-24
L.M. Shen, Z.W. Li, Y.J. Sun*, 2016, Performance Evaluation of Conventional Demand Response at Building-group-level under Different Electricity Pricings, Energy and Buildings, 128, 143-154.
L.M. Shen, Y.J. Sun*, 2016, Performance comparisons of two system sizing approaches for net zero energy building clusters under uncertainties, Energy and Buildings, 127(1), 10-21
A.B. Li, X.H. Xu, Y.J. Sun*, 2016, A Study on Pipe-embedded Wall Integrated with Ground Source-coupled Heat Exchanger for Enhanced Building Energy Efficiency in Diverse Climate Regions, Energy and Buildings, 121(1), 139–151
Y.J He, Y.J. Sun, S. Zhang*, Y.L. Lyu, G.M. Chen, 2016, Initial Ratio Optimization for the Ejector Cooling System with Thermal Pumping Effect (ECSTPE), Energy Conversion and Management, 113, 281-289
D.C. Gao, Y.J. Sun*, 2016, A GA-Based Coordinated Demand Response Control for Building Group Level Peak Demand Limiting with Benefits to Grid Power Balance, Energy and Buildings, 110(1), 31–40
A.B. Li, X.H. Xu, J.L. Xie*, Y.J. Sun, 2016, Development of a Simplified Heat Transfer Model of Hollow Blocks by Using Finite Element Method in Frequency Domain, Energy and Buildings, 111, 76-86
Y.D. Liao, Y.J. Sun, G.S. Huang*, 2015, Robustness analysis of chiller sequencing control, Energy Conversion and Management, 103, 180-190
D.C. Gao, Y.J. Sun*, Y.H. Lu, 2015, A Robust Demand Response Control of Commercial Buildings for Smart Grid under Load Prediction Uncertainty, Energy, 93 (1), 275-283
Y.J. Sun*, P. Huang, G.S. Huang, 2015, A Multi-Criteria System Design Optimization for Net Zero Energy Buildings under Uncertainties, Energy and Buildings, 97(15), 196–204.
Y.H. Lu, S.W. Wang*, Y.J. Sun, C.C. Yan, 2015, Optimal Scheduling of Buildings with Energy Generation and Thermal Energy Storage under Dynamic Electricity Pricing Using Mixed-integer Nonlinear Programming, Applied Energy, 147(1), 49-58.
Y.J. Sun*, 2015, Sensitivity Analysis of Macro-parameters in the System Design of Net Zero Energy Building, Energy and Buildings, 86, 464-477
Y.D. Liao, G.S. Huang*, Y.J. Sun, L.F. Zhang, 2014, Uncertainty Analysis for Chiller Sequencing Control, Energy and Buildings, 85, 187-198.
B.R. Cui, S.W. Wang*, Y.J. Sun, 2014, Life-cycle Cost Benefit Analysis and Optimal Design of Small Scale Active Storage System for Building Demand Limiting, Energy, 73, 787–800
Z.W. Li, G.S. Huang*, Y.J. Sun, 2014, Stochastic Chiller Sequencing Control, Energy and Buildings, 84, 203-213
X. Xue, S.W. Wang*, Y.J. Sun, Fu Xiao, 2014，An interactive building power demand management strategy for facilitating smart grid optimization, Applied Energy,116(1), 297-310
Y.J. Sun, S.W. Wang*, B.R. Cui, 2013, Energy Performance Enhancement of Hong Kong International Airport through Chilled Water System Integration and Control Optimization, Applied Thermal Engineering, 60 (1-2), 303-315
Y.J. Sun, S.W. Wang*, F. Xiao, 2013, In-situ Performance Comparison and Evaluation of Three Chiller Sequencing Control Strategies in a Super High-rise Building, Energy and Buildings, 61, 333-343
Y.J. Sun, S.W. Wang*, F. Xiao, D.C. Gao, 2013, Peak Load Shifting Control Using Different Cold Thermal Energy Storage Facilities in Commercial Buildings: A Review, Energy Conversion and Management, 71, 101-114
Y.J. Sun, G.S. Huang*, Z.W. Li, S.W. Wang, 2013, Multiplexed Optimization for Complex Air Conditioning Systems, Building and Environment, 65, 99-108
Y.J. Sun, S.W. Wang*, 2013, Development and Validation of a Simplified Online Cooling Load Prediction for a Super High-rise Building in Hong Kong, Energy Conversion and Management, 68, 20-27
S.W. Wang*, D.C. Gao, Y.J. Sun and F. Xiao, 2013, An online adaptive optimal control strategy for complex building chilled water systems involving intermediate heat exchangers, Building and Environment. 50(1), 614–628
K. Shan, S.W. Wang*, F. Xiao, Y.J. Sun, 2013, Sensitivity and Uncertainty Analysis of Measurements in Outdoor air flow Control Strategies, HVAC&R Research, 19, 423-434
K. Shan, S.W. Wang*, F. Xiao, Y.J. Sun, 2013, Sensitivity and Uncertainty Analysis of Cooling Water Control Strategies, HVAC&R Research, 19, 435-443
N. Zhu, K. Shan, S.W. Wang*, Y.J. Sun, 2013, An Optimal Control Strategy with Enhanced Robustness for Air-conditioning Systems Considering Model and Measurement Uncertainties, Energy and Buildings. 67, 540-550
G.S. Huang, Y.J. Sun*, S.W. Wang, 2013, Building instantaneous cooling load fused measurement: multiple-sensor-based fusion versus chiller-model-based fusion, Building Services Engineering Research & Technology, 34(2), 177-194
Y.J. Sun, S.W. Wang*, F. Xiao, G.S. Huang, 2012, A Study of Pre-cooling Impacts on Peak Demand Limiting In Commercial Buildings, HVAC&R Research, 18(6), 1098-1111
K. Shan, Y.J. Sun, S.W. Wang*, C.C. Yan, 2012, Development and In-situ Validation of A Multi-zone Demand-Controlled Ventilation Strategy Using A Limited Number of Sensors, Building and Environment, 57, 28-37
D.C. Gao, S.W. Wang*, Y.J. Sun, F. Xiao, 2012, Diagnosis of the Low Temperature Difference Syndrome in the Chilled Water System of a Super High-rise Building: A Case Study, Applied Energy, 98, 597–606
G.S. Huang*, Y.J. Sun, P. Li, 2011, Fusion of redundant measurements for enhancing the reliability of total cooling load based chiller sequencing control, Automation in Construction, 20 (7), 789–798
D.C. Gao, S.W. Wang*, Y.J. Sun, 2011, A fault-tolerant and energy efficient control strategy for primary–secondary chilled water systems in buildings, Energy and Buildings, 43(12), 3646-3656
N. Zhu, S.W. Wang*, Z.J. Ma, Y.J. Sun, 2011, Energy Performance and Optimal Control of Air-conditioned Buildings with Envelopes Enhanced by Phase Change Materials, Energy Conversion and Management, 52(10), 3197-3205
Y.J. Sun, S.W. Wang*, G.S. Huang, 2010, A Demand Limiting Strategy for Maximizing Monthly Cost Savings of Commercial Buildings, Energy and Buildings, 42(11), 2219-2230
Y.J. Sun, S.W. Wang, G.S. Huang*, 2010, Online Sensor Fault Diagnosis for Robust Chiller Sequencing Control, International Journal of Thermal Sciences, 49(3), 589-602 (SCI cited)
Y.J. Sun, S.W. Wang*, G.S. Huang, 2010, Model-based Optimal Start Control Strategy for Multi-chiller Plants in Commercial Buildings, Building Services Engineering Research & Technology, 31(2), 113-129
S.W. Wang*, Z.W. Sun, Y.J. Sun, Zhu Na, 2010, Online Optimal Ventilation Control of Building Air-conditioning Systems, Indoor and Built Environment, 20(1), 129-136
Y.J. Sun, S.W. Wang, G.S. Huang*, 2009, Chiller Sequencing Control with Enhanced Robustness for Energy Efficient Operation, Energy and Buildings, 41(11), 1246-1255
G.S. Huang, S.W. Wang*, F. Xiao, Y.J. Sun, 2009, A data fusion scheme for building automation systems of building central chilling plants, Automation in Construction, 18 (3) 302-309
G.S. Huang, S.W. Wang*, Y.J. Sun, 2008, Enhancing the reliability of chiller sequencing control using fused measurement of building cooling load, HVAC&R Research, 14 (6) 941-958