All Issue

2025 Vol.45, Issue 5 Preview Page

Research Article

Performance Evaluation of a Natural Solar Lighting and LED Hybrid Louver Window System for Energy Saving in Indoor Vertical Farm

식물공장의 조명 전력에너지 절감을 위한 태양광 LED 하이브리드 루버 외피기술 성능 평가

Youngsub An1
,
Ngoc Mihn Kien2
,
Hong-Jin Joo3
,
Kyoung-Ho Lee3*
,
Hyun-Hee Lee4
,
Seoyong Shin5
,
Sae-Byul Kang6
안 영섭1
,
Kien Ngoc Mihn2
,
주 홍진3
,
이 경호3*
,
이 현희4
,
신 서용5
,
강 새별6
1Principal Engineer, Renewable Energy Laboratory System, Korea Institute of Energy Research, Ph.D.
2Postdoctoral Researcher, Department of Information and Communication Engineering, Myongji University, Ph.D.
3Principal Researcher, Renewable Energy Laboratory System, Korea Institute of Energy Research, Ph.D.
4Engineer, Energy Convergence System Research Department, Korea Institute of Energy Research
5Professor, Department of Information and Communication Engineering, Myongji University, Ph.D.
6Principal Researcher, Energy Convergence System Research Department, Korea Institute of Energy Research, Ph.D.
1한국에너지기술연구원 신재생시스템연구실, 책임기술원, 공학박사
2명지대학교 정보통신학과, 박사후 연구원, 공학박사
3한국에너지기술연구원 신재생시스템연구실, 책임연구원, 공학박사
4한국에너지기술연구원 에너지융합시스템연구단, 기술원
5명지대학교 정보통신학과, 교수, 공학박사
6한국에너지기술연구원 에너지융합시스템연구단, 책임연구원, 공학박사
*Corresponding Author
30 October 2025. pp. 91-102
PDF XML Citation
Abstract

This study developed a hybrid louver window system (HLWS) that integrates natural solar lighting with light-emitting diode (LED) lighting to reduce the electrical energy consumption in an indoor vertical farm. The proposed system enables the required photosynthetic photon flux density (PPFD) for plant growth through a combination of natural solar and LED lighting. The HLWS is a south-facing louver structure developed to increase natural solar light transmittance and has measurements of 890 (w) × 1,600 (h) mm. Because the intensity of natural solar lighting varies significantly with weather conditions, dimming control of the LED is employed to maintain the target PPFD level required by the plants. Consequently, when applying the HLWS to an indoor vertical farm, the system first maximizes the utilization of available natural solar lighting and then compensates the remaining PPFD deficit through adjustable LED output. The performance of the developed HLWS was evaluated through experimental verification using a full-scale mock-up facility, and numerical simulations were conducted using LightTools software. The results confirmed the PPFD distribution characteristics of the hybrid system combining natural solar lighting and LED and demonstrated the potential of the HLWS to reduce electrical energy consumption by up to 11% in an indoor vertical farm by effectively utilizing natural solar lighting.

Keywords
Natural solar lighting
LED
Indoor vertical farm
PPFD
Grating
Electric energy
키워드
태양광
인공광
식물공장
광량
그레이팅
전력에너지
References
1

Smart Agriculture Market by Offering, Agriculture Type, Farm Size, Applicationand Region - Global Forecast to 2028, Markets&Markets, Pune, India, 2023.

2

Precedence Research, Vertical Farming Market Size and Forecast 2024 to 2034, Precedence Research, West Hartford, USA, 2024.

3

Rural Researcher Institute, Policy Tasks of Vertical Farming in South Korea, Rural Researcher Institute, Naju, Republic of Korea, 2023.

4

Ministry of Trade, Industry and Energy (MOTIE), Vertical Farms Open a New Future for Agri-Industry in Industrial Complexes! Enforcement of the Amended Related Laws Starts Today, Ministry of Agriculture, Food and Rural Affairs (MAFRA), Ministry of Trade, Industry and Energy (MOTIE), and Ministry of Land, Infrastructure and Transport (MOLIT), Sejong, Republic of Korea, 2024.

5

iFarm, Vertical Farming Energy Consumption, 2024, https://ifarm.fi/blog/how-much-electricity-does-a-vertical-farm-consume. last accessed on the 30th September 2025.

6

National Institute of Agricultural Sciences, Study on the Development a Closed-Type Light System to Use Both Artificial Lights and Natural Light In Smart Farm(Plant Factory), National Institute of Agricultural Sciences, Wanju, Republic of Korea, 2020.

7

Vu, D. T., Hoang, V., Seoyong, S., Tran, Q. T., and Ngoc, H. V., New Mechanism of a Daylighting System Using Optical-Fiber-Less Design for Illumination in Multi-Storey Building, Solar Energy, Vol. 225, pp. 412-426, 2021, https://doi.org/10.1016/j.solener.2021.07.053.

10.1016/j.solener.2021.07.053
8

Han, H. J., Mehmood, M. U., Ahmed, R., Kim, Y., Lim, S. H., and Chun, W., An Advanced Lighting System Combining Solar and an Artificial Light Source for Constant Illumination and Energy Saving in Buildings, Energy and Buildings, Vol. 203, 109404, 2019, https://doi.org/10.1016/j.enbuild.2019.109404.

10.1016/j.enbuild.2019.109404
9

Chen, H., Cai, B., Wang, Y., and Yang, J., Study on Natural Lighting and Electrical Performance of Louvered Photovoltaic Windows in Hot Summer and Cold Winter Areas, Energy and Buildings, Vol. 271, 112313, 2022, https://doi.org/10.1016/j.enbuild.2022.112313.

10.1016/j.enbuild.2022.112313
10

Ullah, I. and Shin, S., Highly Concentrated Optical Fiber-Based Daylighting Systems for Multi-Floor Office Buildings, Energy and Buildings, Vol. 72, pp. 246-261, 2014, https://doi.org/10.1016/j.enbuild.2013.12.031.

10.1016/j.enbuild.2013.12.031
11

An, Y., Minh, K. N., Joo, H. J., Lee, K. H., Lee, W. J., Kim, M. H., Shin, S., and Kang, S. B., Development and Performance Evaluation of a Hybrid Louver Window System Using Natural Light and LED for Energy-Efficient Vertical Farming Building, Building and Environment, Vol. 279, 113020, 2025, https://doi.org/10.1016/j.buildenv.2025.113020.

10.1016/j.buildenv.2025.113020
Information
  • Publisher :Korean Solar Energy Society
  • Publisher(Ko) :한국태양에너지학회
  • Journal Title :Journal of the Korean Solar Energy Society
  • Journal Title(Ko) :한국태양에너지학회 논문집
  • Volume : 45
  • No :5
  • Pages :91-102
  • Received Date : 2025-10-02
  • Revised Date : 2025-10-15
  • Accepted Date : 2025-10-20
  • A Corrigendum to this article was published on 30 December 2025.
    This article has been updated.
  • DOI :https://doi.org/10.7836/kses.2025.45.5.091
Journal Informaiton Journal of the Korean Solar Energy Society Journal of the Korean Solar Energy Society
Online Submission
  • NRF
  • KOFST
  • crossref crossmark
  • crossref cited-by
  • crosscheck
  • orcid
  • open access
  • ccl
Journal Informaiton Journal Informaiton - close