Amirkabir Journal of Mechanical Engineering

Amirkabir Journal of Mechanical Engineering

An Intelligent Two-Layer Controller Based on Hysteresis and PID Logic for Performance Improvement of a Direct-Expansion Solar Heat Pump

Document Type : Research Article

Authors
Abouzar Taghizadeh 1
Vahid Rezaee 2
Ehsan Abdollahzadeh 2
1 Department of Electrical Engineering, Technical and Vocational University (TVU), Tehran, Iran
2 Department of Mechanical Engineering, Technical and Vocational University (TVU), Tehran, Iran
10.22060/mej.2026.25760.7967
Abstract
This study proposes an innovative framework for designing a two-layer intelligent controller for direct expansion solar heat pump systems. The system consists of a flat-plate solar collector–evaporator with a surface area of 3.1 m², a variable-frequency hermetic rotary compressor, a hot-water storage tank with a volume of 0.1 m³, a finned-tube condenser, and a capillary tube (expansion valve). The first layer, based on hysteresis logic, utilizes DS18B20 digital temperature sensors and an Arduino microcontroller to perform basic control and energy management under normal operating conditions. This layer was designed and evaluated experimentally. The second layer comprises a PID controller whose parameters are tuned according to the system’s ARX model using the direct synthesis method. This controller activates under severe disturbances, such as sudden variations in solar irradiance or inlet temperature, restoring the system’s control accuracy to its optimal level. Quantitative results obtained from experimental implementation under three scenarios—steady-state, step disturbance, and periodic disturbance—demonstrate that the proposed controller, in comparison with the standalone hysteresis controller, reduces the RMS temperature error under steady-state conditions from 0.95°C to 0.28°C (a 70.5% reduction), and decreases the number of compressor on/off cycles from 42 to 35 (a 16.6% reduction). Furthermore, energy consumption under disturbance scenarios is reduced by 24.4% and 19.6%, respectively, compared to the standalone hysteresis controller.
Keywords
Solar Heat Pump
PID Controller
Modeling
Hysteresis Logic
Energy
Subjects
[1] S.I.d.M. Resende, H.A.G. Diniz, R.N.d. Faria, R. Nunes de Oliveira, Design and Experimental Evaluation of a Controller for a Direct-Expansion Solar-Assisted Heat Pump with Propane, Processes, 13(11) (2025) 3583.
[2] V. Rezaee, A. Taghizadeh, Evaluating of the Impact of Environmental Indicators on Thermal Comfort for Different Climates in Iran Using the PMV Model, Amirkabir Journal of Mechanical Engineering, 57(1) (2025) 3-24.(In Persian)
[3] D.E. Seborg, T.F. Edgar, D.A. Mellichamp, F.J. Doyle III, Process dynamics and control, John Wiley & Sons, 2016.
[4] S. Anil, H. Srinaath, M. Jayakumar, Comparative Analysis of ON/OFF, PID and Model Predictive Control System in HVAC Systems, in:  2023 Innovations in Power and Advanced Computing Technologies (i-PACT), IEEE, 2023, pp. 1-5.
[5] K.J. Åström, T. Hägglund, Advanced PID control, ISA-The Instrumentation, Systems and Automation Society, 2006.
[6] G. Ulpiani, M. Borgognoni, A. Romagnoli, C. Di Perna, Comparing the performance of on/off, PID and fuzzy controllers applied to the heating system of an energy-efficient building, Energy and Buildings, 116 (2016) 1-17.
[7] V. Rezaee, A. Taghizadeh, M. Masomnezhad, Comparative feasibility study of two direct expansion solar water heater heat pump systems in Rasht climate, Amirkabir Journal of Mechanical Engineering, 57(5) (2025) 589-610. (In Persian)
[8] X. Kong, P. Sun, S. Dong, K. Jiang, Y. Li, Experimental performance analysis of a direct-expansion solar-assisted heat pump water heater with R134a in summer, International Journal of Refrigeration, 91 (2018) 12-19.
[9] W.M. Duarte, T.F. Paulino, S.G. Tavares, A.A. Maia, L. Machado, Feasibility of solar-geothermal hybrid source heat pump for producing domestic hot water in hot climates, International Journal of Refrigeration, 124 (2021) 184-196.
[10] X. Kong, Y. Yang, M. Zhang, Y. Li, J. Li, Experimental investigation on a direct-expansion solar-assisted heat pump water heater using R290 with micro-channel heat transfer technology during the winter period, International Journal of Refrigeration, 113 (2020) 38-48.
[11] W.M. Duarte, T.F. Paulino, J.J. Pabon, S. Sawalha, L. Machado, Refrigerants selection for a direct expansion solar assisted heat pump for domestic hot water, Solar Energy, 184 (2019) 527-538.
[12] M. Masiukiewicz, M. Tańczuk, S. Anweiler, G. Streckienė, S. Boldyryev, Long-term climate-based sizing and economic assessment of air-water heat pumps for residential heating, Applied thermal engineering, 258 (2025) 124627.
[13] W. Zhenkui, Y. Peihong, J. Hui, W. Yili, Z. Jihong, Z. Zilei, Z. Xiaoming, Heating performance of solar heat pump heating system with aluminum tube collector, IEEE Access, 9 (2021) 26491-26501.
[14] K.J. Åström, T. Hägglund, PID control, IEEE Control Systems Magazine, 1066 (2006) 30-31.
[15] K. Ogata, Modern control engineering, Prentice hall, 2010.
[16] N. Han, J. Xu, Multilayer decoupling control of photovoltaic integrated heat pump based on expected value, in:  Journal of Physics: Conference Series, IOP Publishing, 2024, pp. 012005.
[17] Y. Han, L. Ma, J. Zhang, P. Mi, X. Guo, Research on the adaptive proportional-integral control method of a direct-expansion photovoltaic-thermal heat pump system, Energy, 281 (2023) 128077.
[18] S. Chaturvedi, D. Chen, A. Kheireddine, Thermal performance of a variable capacity direct expansion solar-assisted heat pump, Energy Conversion and management, 39(3-4) (1998) 181-191.
[19] Z. Zhao, B. Wang, X. Li, W. Shi, Adaptive model predictive control of a residential solar-air hybrid heat pump system, Energy Conversion and Management, 321 (2024) 119026.
[20] F.E.M. Garcia, J.A.G. Camperos, H.Y. Jaramillo, Fuzzy Controller for a Thermal Process by Flat Solar Collector Assisted by a Heat Pump Using Arduino, International Review of Automatic Control, 15(1) (2022) 20.
[21] S. Chebaane, S.D. Farahani, T.S. Abdennaji, L. Kolsi, A. Karimipour, W. Aich, ANFIS approach and thermal performance of solar air heaters integrated with phase change materials and porous foam gradient under mechanical vibrations, Case Studies in Thermal Engineering, 72 (2025) 106267.
[22] H. Weeratunge, G. Narsilio, J. De Hoog, S. Dunstall, S. Halgamuge, Model predictive control for a solar assisted ground source heat pump system, Energy, 152 (2018) 974-984.
[23] A. Afram, F. Janabi-Sharifi, Theory and applications of HVAC control systems–A review of model predictive control (MPC), Building and environment, 72 (2014) 343-355.
[24] M. Beaudin, H. Zareipour, Home energy management systems: A review of modelling and complexity, Energy Solutions to Combat Global Warming,  (2016) 753-793.
[25] X. Wu, Y. Xu, X. Wu, J. He, J.M. Guerrero, C.-C. Liu, K.P. Schneider, D.T. Ton, A two-layer distributed cooperative control method for islanded networked microgrid systems, IEEE Transactions on Smart Grid, 11(2) (2019) 942-957.
[26] B. Paris, J. Eynard, S. Grieu, M. Polit, Hybrid PID-fuzzy control scheme for managing energy resources in buildings, Applied Soft Computing, 11(8) (2011) 5068-5080.
[27] F.G. Chata, S. Chaturvedi, A. Almogbel, Analysis of a direct expansion solar assisted heat pump using different refrigerants, Energy Conversion and Management, 46(15-16) (2005) 2614-2624.
[28] A. Simpkins, System identification: Theory for the user, (ljung, l.; 1999)[on the shelf], IEEE Robotics & Automation Magazine, 19(2) (2012) 95-96.
[29] O. Ozen, E. Sariyildiz, H. Yu, K. Ogawa, K. Ohnishi, A. Sabanovic, Practical PID controller tuning for motion control, in:  2015 IEEE International Conference on Mechatronics (ICM), IEEE, 2015, pp. 240-245.
[30] F. Velasco, M. Haddouche, F. Illán-Gómez, J. García-Cascales, Experimental characterization of the coupling and heating performance of a CO2 water-to-water heat pump and a water storage tank for domestic hot water production system, Energy and Buildings, 265 (2022) 112085.
[31] X. Kong, P. Sun, Y. Li, K. Jiang, S. Dong, Experimental studies of a variable capacity direct-expansion solar-assisted heat pump water heater in autumn and winter conditions, Solar Energy, 170 (2018) 352-357.
[32] B. Li, A.G. Alleyne, A dynamic model of a vapor compression cycle with shut-down and start-up operations, International Journal of refrigeration, 33(3) (2010) 538-552.
[33] J.Y. Lee, T. Yim, Energy and flow demand analysis of domestic hot water in an apartment complex using a smart meter, Energy, 229 (2021) 120678.
Amirkabir Journal of Mechanical Engineering
Volume 57, Issue 12
March 2026
Pages 1637-1656