Journal of the Korean Solar Energy Society ISSN:1598-6411(Print) 2508-3562(Online) 한국태양에너지학회 논문집

Most geothermal cooling and heating systems operate with a refined degree of precision. The direct start method, a straightforward approach, repetitively starts and stops based on signals. This frequent cycling generates impact torque, affecting the motor gear and insulator due to voltage and current spikes, thereby reducing lifespan. The product developed in this study minimizes system load and noise by regulating the circulating pump output using the VVVF (Variable Voltage Variable Frequency) control method, which adjusts voltage and frequency to lower power consumption. Additionally, the output of the geothermal water circulation pump is adjusted based on the operating current of the geothermal heat pump according to demand. Although maximum load conditions are rare, oil-based circulation pumps are typically designed with a sufficient margin, often providing a flow rate greater than required. This feature helps reduce energy consumption. By applying these technologies, the COP (Coefficient of Performance) of the system can be improved, allowing cooling and heating systems to operate more efficiently and cost-effectively with variable flow control.