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Advances in Civil Engineering
Volume 2018, Article ID 7867128, 16 pages
https://doi.org/10.1155/2018/7867128
Research Article

Comparison Evaluations of VRF and RTU Systems Performance on Flexible Research Platform

1Department of Digital Appliances R&D Team, Samsung Electronics, Suwon 17804, Republic of Korea
2Building Technologies Research and Integration Center (BTRIC), Oak Ridge National Laboratory, One Bethel Valley Road, Oak Ridge, TN 37831, USA
3Department of Architectural Engineering, Graduate School of Gyeongsang National University, Jinju 52828, Republic of Korea
4Department of Architectural Engineering, ERI, Gyeongsang National University, Jinju 52828, Republic of Korea

Correspondence should be addressed to Young-hak Song; rk.ca.ung@hygnos

Received 19 November 2017; Accepted 12 February 2018; Published 5 April 2018

Academic Editor: Alison Kwok

Copyright © 2018 Je-hyeon Lee et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The energy performance of a variable refrigerant flow (VRF) system was evaluated using an occupancy-emulated research building in the southeastern region of the United States. Full- and part-load performance of the VRF system in heating and cooling seasons was compared with a conventional rooftop unit (RTU) variable-air-volume system with electric resistance heating. During both the heating and cooling seasons, full- and part-load conditions (i.e., 100%, 75%, and 50% thermal loads) were maintained alternately for 2 to 3 days each, and the energy use, thermal conditions, and coefficient of performance (COP) for the RTU and VRF system were measured. During the cooling season, the VRF system had an average COP of 4.2, 3.9, and 3.7 compared with 3.1, 3.0, and 2.5 for the RTU system under 100%, 75%, and 50% load conditions and resulted in estimated energy savings of 30%, 37%, and 47%, respectively. During the heating season, the VRF system had an average COP ranging from 1.2 to 2.0, substantially higher than the COPs of the RTU system, and resulted in estimated energy savings of 51%, 47%, and 27% under the three load conditions, respectively.