IDEAS home Printed from https://ideas.repec.org/a/gam/jeners/v18y2025i4p792-d1586552.html
   My bibliography  Save this article

Augmenting Residential AC Electric Water Heating with Dedicated Direct-to-Element DC Solar Photovoltaic

Author

Listed:
  • Daniel Pfister

    (Industrial Engineering, Stellenbosch University, Stellenbosch 7600, South Africa)

  • Arnold Johan Rix

    (Electrical and Electronic Engineering, Stellenbosch University, Stellenbosch 7600, South Africa)

  • Marthinus Johannes Booysen

    (Industrial Engineering, Stellenbosch University, Stellenbosch 7600, South Africa
    Electrical and Electronic Engineering, Stellenbosch University, Stellenbosch 7600, South Africa)

Abstract

Residential water heating represents one of the most energy-intensive household applications, particularly in South Africa, where immersed resistive element heating dominates. Solar photovoltaic systems provide a promising solution for augmenting grid-based electrical water heaters, offering energy cost savings and environmental benefits. This study evaluates a novel approach to integrate solar photovoltaic directly into electrical water heater systems without using inverters. Using a combination of field experiments and simulation, four heating strategies were assessed, namely: “grid only”, “solar medium”, “solar heavy”, and “solar timer”. Metrics such as solar augmentation ratio, solar utilization, and cold event frequency were analyzed for different seasons using real-world and simulated water usage profiles. Results demonstrate significant grid energy reductions through solar augmentation, particularly in warmer seasons. However, the effectiveness of the strategies varies, with increased solar utilization often correlated with a higher frequency of cold events. A hybrid seasonal strategy is proposed to optimize energy savings while maintaining user comfort. This work highlights the potential of direct DC solar photovoltaic integration as a cost-effective and sustainable enhancement for residential water heating.

Suggested Citation

  • Daniel Pfister & Arnold Johan Rix & Marthinus Johannes Booysen, 2025. "Augmenting Residential AC Electric Water Heating with Dedicated Direct-to-Element DC Solar Photovoltaic," Energies, MDPI, vol. 18(4), pages 1-16, February.
  • Handle: RePEc:gam:jeners:v:18:y:2025:i:4:p:792-:d:1586552
    as

    Download full text from publisher

    File URL: https://www.mdpi.com/1996-1073/18/4/792/pdf
    Download Restriction: no

    File URL: https://www.mdpi.com/1996-1073/18/4/792/
    Download Restriction: no
    ---><---

    References listed on IDEAS

    as
    1. Zhang, Xingxing & Zhao, Xudong & Xu, Jihuan & Yu, Xiaotong, 2013. "Characterization of a solar photovoltaic/loop-heat-pipe heat pump water heating system," Applied Energy, Elsevier, vol. 102(C), pages 1229-1245.
    2. Urban, Frauke & Geall, Sam & Wang, Yu, 2016. "Solar PV and solar water heaters in China: Different pathways to low carbon energy," Renewable and Sustainable Energy Reviews, Elsevier, vol. 64(C), pages 531-542.
    3. Asgari, Nima & Hayibo, Koami Soulemane & Groza, Julia & Rana, Shafquat & Pearce, Joshua M., 2025. "Greenhouse applications of solar photovoltaic driven heat pumps in northern environments," Renewable and Sustainable Energy Reviews, Elsevier, vol. 207(C).
    Full references (including those not matched with items on IDEAS)

    Most related items

    These are the items that most often cite the same works as this one and are cited by the same works as this one.
    1. Ren, Xiao & Yu, Min & Zhao, Xudong & Li, Jing & Zheng, Siming & Chen, Fucheng & Wang, Zhangyuan & Zhou, Jinzhi & Pei, Gang & Ji, Jie, 2020. "Assessment of the cost reduction potential of a novel loop-heat-pipe solar photovoltaic/thermal system by employing the distributed parameter model," Energy, Elsevier, vol. 190(C).
    2. Sovacool, Benjamin K. & Martiskainen, Mari, 2020. "Hot transformations: Governing rapid and deep household heating transitions in China, Denmark, Finland and the United Kingdom," Energy Policy, Elsevier, vol. 139(C).
    3. Shafieian, Abdellah & Khiadani, Mehdi & Nosrati, Ataollah, 2018. "A review of latest developments, progress, and applications of heat pipe solar collectors," Renewable and Sustainable Energy Reviews, Elsevier, vol. 95(C), pages 273-304.
    4. Makki, Adham & Omer, Siddig & Sabir, Hisham, 2015. "Advancements in hybrid photovoltaic systems for enhanced solar cells performance," Renewable and Sustainable Energy Reviews, Elsevier, vol. 41(C), pages 658-684.
    5. Teresa Pakulska, 2021. "Green Energy in Central and Eastern European (CEE) Countries: New Challenges on the Path to Sustainable Development," Energies, MDPI, vol. 14(4), pages 1-19, February.
    6. Wang, Zhangyuan & Yang, Wansheng & Qiu, Feng & Zhang, Xiangmei & Zhao, Xudong, 2015. "Solar water heating: From theory, application, marketing and research," Renewable and Sustainable Energy Reviews, Elsevier, vol. 41(C), pages 68-84.
    7. Sichilalu, Sam & Mathaba, Tebello & Xia, Xiaohua, 2017. "Optimal control of a wind–PV-hybrid powered heat pump water heater," Applied Energy, Elsevier, vol. 185(P2), pages 1173-1184.
    8. Badiei, A. & Golizadeh Akhlaghi, Y. & Zhao, X. & Shittu, S. & Xiao, X. & Li, J. & Fan, Y. & Li, G., 2020. "A chronological review of advances in solar assisted heat pump technology in 21st century," Renewable and Sustainable Energy Reviews, Elsevier, vol. 132(C).
    9. Wang, Zhangyuan & Guo, Peng & Zhang, Haijing & Yang, Wansheng & Mei, Sheng, 2017. "Comprehensive review on the development of SAHP for domestic hot water," Renewable and Sustainable Energy Reviews, Elsevier, vol. 72(C), pages 871-881.
    10. Muhammad Saydal Khan & Ali Tahir & Imtiaz Alam & Sohail Razzaq & Muhammad Usman & Wajahat Ullah Khan Tareen & Nauman Anwar Baig & Salman Atif & Mehwish Riaz, 2021. "Assessment of Solar Photovoltaic Water Pumping of WASA Tube Wells for Irrigation in Quetta Valley Aquifer," Energies, MDPI, vol. 14(20), pages 1-14, October.
    11. Ma, Ben & Yu, Yihua & Urban, Frauke, 2018. "Green transition of energy systems in rural China: National survey evidence of households’ discrete choices on water heaters," Energy Policy, Elsevier, vol. 113(C), pages 559-570.
    12. Herrando, M. & Coca-Ortegón, A. & Guedea, I. & Fueyo, N., 2023. "Experimental validation of a solar system based on hybrid photovoltaic-thermal collectors and a reversible heat pump for the energy provision in non-residential buildings," Renewable and Sustainable Energy Reviews, Elsevier, vol. 178(C).
    13. Nizetic, S. & Coko, D. & Marasovic, I., 2014. "Experimental study on a hybrid energy system with small- and medium-scale applications for mild climates," Energy, Elsevier, vol. 75(C), pages 379-389.
    14. Mohanraj, M. & Belyayev, Ye. & Jayaraj, S. & Kaltayev, A., 2018. "Research and developments on solar assisted compression heat pump systems – A comprehensive review (Part-B: Applications)," Renewable and Sustainable Energy Reviews, Elsevier, vol. 83(C), pages 124-155.
    15. Zhang, Tao & Zhang, Yufan & Shi, Zhengrong & Pei, Gang & Cai, Jingyong, 2022. "Preliminary investigation on the switching time of a photovoltaic solar-assisted heat-pump/heat-pipe hybrid system," Applied Energy, Elsevier, vol. 324(C).
    16. Yawei Wang & Frauke Urban & Yuan Zhou & Luyi Chen, 2018. "Comparing the Technology Trajectories of Solar PV and Solar Water Heaters in China: Using a Patent Lens," Sustainability, MDPI, vol. 10(11), pages 1-29, November.
    17. Eui Guk Jung & Joon Hong Boo, 2019. "A Novel Analytical Modeling of a Loop Heat Pipe Employing Thin-Film Theory: Part II—Experimental Validation," Energies, MDPI, vol. 12(12), pages 1-15, June.
    18. Urban, Frauke, 2018. "China's rise: Challenging the North-South technology transfer paradigm for climate change mitigation and low carbon energy," Energy Policy, Elsevier, vol. 113(C), pages 320-330.
    19. Acaroğlu, Hakan & Baykul, M. Celalettin, 2018. "Economic guideline about financial utilization of flat-plate solar collectors (FPSCs) for the consumer segment in the city of Eskisehir," Renewable and Sustainable Energy Reviews, Elsevier, vol. 81(P2), pages 2045-2058.
    20. María Herrando & Alba Ramos, 2022. "Photovoltaic-Thermal (PV-T) Systems for Combined Cooling, Heating and Power in Buildings: A Review," Energies, MDPI, vol. 15(9), pages 1-28, April.

    Corrections

    All material on this site has been provided by the respective publishers and authors. You can help correct errors and omissions. When requesting a correction, please mention this item's handle: RePEc:gam:jeners:v:18:y:2025:i:4:p:792-:d:1586552. See general information about how to correct material in RePEc.

    If you have authored this item and are not yet registered with RePEc, we encourage you to do it here. This allows to link your profile to this item. It also allows you to accept potential citations to this item that we are uncertain about.

    If CitEc recognized a bibliographic reference but did not link an item in RePEc to it, you can help with this form .

    If you know of missing items citing this one, you can help us creating those links by adding the relevant references in the same way as above, for each refering item. If you are a registered author of this item, you may also want to check the "citations" tab in your RePEc Author Service profile, as there may be some citations waiting for confirmation.

    For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: MDPI Indexing Manager (email available below). General contact details of provider: https://www.mdpi.com .

    Please note that corrections may take a couple of weeks to filter through the various RePEc services.

    IDEAS is a RePEc service. RePEc uses bibliographic data supplied by the respective publishers.