Novel Methodology for Sizing a Single U-Tube Ground Heat Exchanger Useful at the Early Design Stage

Seung-Hyo Baek,Myoung-Souk Yeo,Byung-Hee Lee

doi:10.3390/buildings11120651

Abstract

Renewable energy system (RES) is an environmentally friendly source of energy. A suitable design of RES is crucial to implement an energy-efficient building such as a zero energy building (ZEB). The significance of appropriate decision-making for the successful implementation of energy-efficient buildings has been increasing. In addition, the identification of the sizing of RES is equally important for architects or HVAC engineers. In this study, a novel sizing method for a single U-tube ground heat exchanger (GHE) is proposed. A transient thermal analysis for a single GHE is performed by considering ground temperature recovery effect as well as other major design parameters. The results are used to design the proposed sizing method and were verified by transient simulations for different design cases. Additionally, it was observed that the coefficient of variation of root mean square error (CV(RMSE)) for all ten design cases was lower than 15% during the heating and cooling seasons. Thus, the proposed design method can be used for sizing a GHE in the early design stage.

Highlights

The construction of energy-efficient buildings has been inevitable over the past years to mitigate global warming
The second step of verification compares the change in specific heat extraction rate (SHER) using the design method and transient simulation
Ten design cases were generated by combining different values of influential performance parameters

Summary

Introduction

The construction of energy-efficient buildings has been inevitable over the past years to mitigate global warming. The implementation of the zero-energy building (ZEB) is regarded as one of the most effective ways to reduce greenhouse gas emissions from buildings. In addition to the implementation of the ZEB, it was experimentally demonstrated that the usage of different types of renewable energy systems (RES) in a building effectively lowers its dependency on fossil fuel [2]. The design process of ZEB is more complex than that of conventional buildings; it must be designed carefully. This can be achieved by appropriate decision-making during the design process by architects and HVAC engineers. Decision-making in the early design stage is more influential to the performance of the building than that in the later stages because, decision-making in the early stage helps to determine approximately 80% of the operational costs of a building as well as environmental impacts [3]

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