Study on the Optimum Design of a Ground Heat Pump System Using Optimization Algorithms

Abstract

Geothermal energy has attracted attention as a high-efficiency energy source that can be used year-round, but it has a relatively higher initial investment cost. For the design of ground source heat pump (GSHP) systems, a calculation method to determine the capacity of a system to meet the peak load of the target building is usually used. However, this method requires excessive system capacity design, especially regarding buildings with partial load operations. In this study, the optimization of a system design was performed in the view of the cost of the lifecycle cost. Several optimization algorithms were considered, such as the discrete Armijo gradient algorithm, a particle swarm optimization (PSO) algorithm, and a coordinate search method algorithm. The results of the optimization described the system capacity (heat pump, ground heat exchanger, thermal storage tank, etc.) and the cost performance, showing that the total investment cost was reduced compared to the existing design.

Development of Optimal Design Method for Ground-Source Heat-Pump System Using Particle Swarm Optimization

“…The system operation period was set to 20 years, and the subsequent results were compared and analyzed. Particle swarm optimization (PSO) was selected as the optimization algorithm on the basis of a previous study [12]. equipment load), and cooling/heating set-point temperature were considered as internal elements.…”

“…Optimization algorithms were also used in other studies; for example, an optimization algorithm was used to set the characteristics of the passive elements of a building (e.g., direction and area ratio) as design variables and obtain values that lead to minimum energy consumption [11]. Moon et al [12] conducted research on the optimal design of the capacity of a geothermal energy system for office buildings. They conducted research on cost optimization by setting the sum of the initial investment cost and the operating cost over 20 years as the objective function.…”

“…Because vertical closed-loop systems are commonly used in South Korea, due to the small land area [23], a vertical closed-loop geothermal system was introduced to the target buildings and optimized. In this study, the power load was stabilized, and the energy charge was reduced by using the HST with reference to the optimal design model for office buildings [12]. Figure 14 shows the vertical closed-loop geothermal system constructed in dynamic analysis simulation software (TRNSYS).…”

“…EWT represents the temperature of the heat source entering the HP from the GHEX, and the COP of the HP was calculated by dividing the calorific value of the HP by its energy consumption. Equations (11) and (12) show the methods of calculating the COPs of the HP and the system.…”