Open Access

ARTICLE

Energy Supply Characteristics and Economic Analysis of a Coupled Heat Pump–Solar System

Bo Ma¹, Wei Chen¹, Yanbin Li^1,*, Jiamin Fang², Xuan Liu¹, Kai Jiao^2,*, Chao Shen²
1 Research Center of Energy Solution, Powerchina Northwest Engineering Corporation Limited, Xi’an, China
2 School of Architecture and Design, Harbin Institute of Technology, Key Laboratory of Cold Region Urban and Rural Human Settlement Environment Science and Technology, Ministry of Industry and Information Technology, Harbin, China
* Corresponding Author: Yanbin Li. Email: ; Kai Jiao. Email:
(This article belongs to the Special Issue: Smart Thermal Management: Emerging Energy Technologies for Built and Industrial Systems)

Energy Engineering https://doi.org/10.32604/ee.2026.079468

Received 21 January 2026; Accepted 02 July 2026; Published online 12 August 2026

Abstract

Targeting the diverse and highly seasonal loads of existing residential buildings, this study develops a hybrid “solar–air-source heat pump–shower wastewater heat recovery–stratified thermal storage–fan-coil” system, and proposes a temperature-difference-threshold-driven valve–pump coordinated control strategy enabling multi-mode operation. Cross-season typical-day experiments are conducted to quantify energy balance and efficiency. Results indicate that midday during the shoulder and winter seasons forms an overlapping high-efficiency window; the maximum solar contribution ratio reaches 31.17%, and piping heat loss rates are 24%–38%. The air-source heat pump achieves a Coefficient of Performance (COP) of 1.38–3.39; wastewater heat recovery under shower conditions yields an Energy Efficiency Ratio (EER) of approximately 2.8–3.1; fan-coil space heating exhibits an EER of about 8.69–9.34. In summer, coordinated “domestic hot water + space cooling” operation is attainable. Based on local electricity tariffs, the annually normalized energy savings are approximately 2.83 × 10⁴ MJ, with a cost saving of about 6363 RMB; the initial investment is about 18,060 RMB, yielding a simple payback period of roughly 2.84 years. The findings demonstrate that multi-source hybrid heat pump systems offer strong seasonal adaptability and favorable economics in existing residential applications. Further improvements in off-peak integrated efficiency can be achieved by optimizing the TC temperature-difference thresholds, enhancing solar piping insulation, and reducing fan-coil hydronic resistance with improved pump matching. The study provides a reproducible technical pathway and empirical data to support the engineering deployment of hybrid heat sources in residential buildings.

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Keywords

Air source heat pump; economic analysis; solar energy; space heating; wastewater heat pump

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