A team of researchers from Pakistan and China has jointly developed a next-generation solar-assisted heat pump system that could significantly advance clean heating in colder regions and support both countries’ low-carbon transition. The work, published in the peer-reviewed journal Energy (Elsevier), Volume 340, 2025, highlights a technology that uses concentrated solar power to deliver higher efficiency than conventional systems.
The collaboration includes scientists from Southwest Jiaotong University in China, the University of Engineering and Technology in Pakistan, and several partner institutions. Together, they designed an indirect-expansion solar heat pump integrated with a parabolic dish concentrator and a high-concentration conical cavity tube receiver. The authors describe this combination as a completely new approach that has not been studied before, offering a fresh pathway for high-efficiency solar heating.
Testing carried out in China showed that the system demonstrated strong performance metrics: 65.35 percent thermal efficiency, 9.05 percent exergy efficiency, and a coefficient of performance reaching 4.86. These results notably exceed the performance of conventional solar heating systems, making the design a promising option for sustainable heating, especially in colder climates.
The system works by concentrating sunlight onto a small focal point using a parabolic dish. The conical cavity receiver, engineered for high heat absorption, improves the capture and transfer of energy into the heat pump cycle. The study found that when the concentration ratio was increased from 20 to 40, thermal efficiency rose by 32 to 71 percent, temperature lift increased by 10 to 18.5 degrees Celsius, and the COP improved from 3.86 to 5.4. The experimental results closely matched the model’s predictions, providing confidence in the design’s reliability.
Lead author Dr. Sajid Abbas emphasized that the findings make a strong case for deploying concentrated solar-assisted heat pumps in regions with harsh winters. He noted that the study offers both theoretical and practical foundations for applying high-concentration solar collectors to heat-pump systems, which could open new opportunities for large-scale clean-heating solutions.
The research argues that solar heat pumps are an essential technology for decarbonizing the heating sector, aligning with China’s climate targets of peaking carbon emissions by 2030 and reaching carbon neutrality by 2060. The work also supports global clean-energy strategies and could help countries reduce their dependence on fossil-fuel-based heating.
The authors conclude that integrating a parabolic dish with an indirect-expansion heat-pump cycle delivers superior thermal efficiency and improved temperature lift compared to traditional systems. They highlight the potential for the technology to be scaled for residential heating, agricultural use, and industrial applications.
Funding for the project came from the China Postdoctoral Council, Southwest Jiaotong University, and the Fundamental Research Funds for the Central Universities. The study also comes at a time when China and Pakistan are strengthening environmental cooperation under the new Joint Action Plan (2025–2029), which calls for deeper collaboration on environmental protection and green development, including Pakistan’s continued participation in the Belt and Road Initiative’s International Green Development Coalition.
