Capacity control in ground source heat pump systems part II: Comparative analysis between on/off controlled and variable capacity systems

• Published in: International journal of refrigeration Vol. 34; no. 8; pp. 1934 - 1942
• Main Authors: Madani, Hatef, Claesson, Joachim, Lundqvist, Per
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.12.2011; Elsevier
• Subjects: Applied sciences; Control; Contrôle; Devices using thermal energy; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Heat pump; Heat pumps; Modelling; Modélisation; Pompe à chaleur; Refrigerating engineering; Refrigerating engineering. Cryogenics. Food conservation; Simulation; Variable speed; Vitesse variable; Control; Pompe à chaleur; Heat pump; Simulation; Modelling; Contrôle; Variable speed; Vitesse variable; Modélisation; Dimensioning; Refrigeration installation; Heat source; Buildings; Modeling; Varying speed; Comparative study
• ISSN: 0140-7007; 1879-2081; 1879-2081
• DOI: 10.1016/j.ijrefrig.2011.05.012

In the present paper, as the second part of two, modeling and simulation was carried out for a Ground Source Heat Pump (GSHP) system in the presence of all the most important interacting sub-systems such as building, ground heat source, electrical auxiliary heater, and the heat pump unit in order to make a fair and comprehensive comparison between the annual performance of on/off controlled and variable capacity systems. The annual modeling showed that dimensioning of the on/off controlled GSHP based on the peak heat demand of the building plays a significant role when the two control strategies are compared: if the on/off controlled GSHP is dimensioned to cover only 55% of the peak heat demand of the building, the electrical auxiliary, which then covers about 10% of the annual heating demand of the building, makes the SPF of the on/off controlled GSHP to be lower than the one of the variable speed system. On the contrary, when the on/off controlled system is dimensioned to cover more than 65% of the building’s peak heat demand, i.e. more than 95% of the annual heat demand of the building, there is no considerable difference between the SPFs of the on/off controlled and variable capacity systems.