Performance investigation and economic benefits of new control strategies for heat pump-gas fired water heater hybrid system

Gang Li and Yuqing Du

Applied Energy, 2018, vol. 232, issue C, 118 pages

Abstract: More recently, the hybrid system equipped with the combination of heat pump and gas fired water heater in one device is increasingly attracting people’s attention from both the industry and academia. In this study, the hybrid system with two control strategies is presented as the alternative option for domestic hot water supply and space heating with the aim of revealing its economic benefits. For the control strategy I, the two heating sources, i.e. heat pump and gas heater, can be switched and there are only two modes: heat pump mode, and gas heater mode. While for the control strategy II, the two heating sources could be handled with the proper arrangement for the loading share. There are 3 modes under this control strategy: heat pump mode, hybrid mode, and gas heater mode. The auxiliary resistance heater is used for heat pump mode if necessary, not for the hybrid mode. Various climate conditions, water initial temperature and final temperature are investigated for the hybrid system, and different heating supply forms are compared. Regarding the domestic hot water demand of 70 L per apartment per day, the gas heater can lead to a ∼38% operation energy cost saving from electric heater, and both of the two control strategies with hybrid system can result in a ∼20% to ∼65% more operation energy cost reduction than gas heater under climate condition of −5 °C to 20 °C, with a more pronounced reduction towards hot climates. Control strategy II, as the most cost-efficient option, can achieve a ∼10% to ∼23% more energy cost saving than strategy I, especially under climate condition of 0 °C to −12 °C. In the hybrid mode with strategy II, a decrease of the final temperature, results in a better economic merit. Regarding the hourly under-flooring heating case, the control strategy II, as the best option, can lead to a ∼6% to ∼70% more hourly process energy cost saving compared with the gas heater from −15 °C to 20 °C ambient conditions. During the typical heating season with ambient (−15 °C to 7 °C), the lowest process energy cost can be achieved by control strategy II. In the same external conditions, the under-flooring heating application has a lower system operation energy process cost than the indoor radiator heating case.

Keywords: Hybrid system; Heat pump water heater; Gas fired water heater; Economic benefit; Control strategy; Residential heating (search for similar items in EconPapers)
Date: 2018
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (10)

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0306261918313801
Full text for ScienceDirect subscribers only

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:eee:appene:v:232:y:2018:i:c:p:101-118

Ordering information: This journal article can be ordered from
http://www.elsevier.com/wps/find/journaldescription.cws_home/405891/bibliographic
http://www.elsevier. ... 405891/bibliographic

DOI: 10.1016/j.apenergy.2018.09.065

Access Statistics for this article

Applied Energy is currently edited by J. Yan

More articles in Applied Energy from Elsevier
Bibliographic data for series maintained by Catherine Liu ().