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• Low energy building performances in Qinghai-Tibetan Plateau were measured and simulated. • Feasibility of low energy building was evaluated by the comparison with regulated standards. • ERV (energy recovery ventilation) combined with solar thermal collector was proposed. • The pleasant indoor comfort could be achieved with energy demand of 16.1 kW h/(m2 year). • Envelope performances and indoor air quality etc. were measured and analyzed. Low energy buildings are an efficient approach to meet space heating requirements and saving energy. Studies of low energy buildings mainly focus on cold climate regions. However, there is less research on the feasibility of low energy buildings on Qinghai-Tibetan Plateau located in a severely cold climatic region. Therefore, a low energy building equipped with an integrated heating system was built on Qinghai-Tibetan Plateau. The performance of the low energy building was quantitatively evaluated by field measurement and dynamic TRNSYS simulation. To be specific, the indoor temperature and relative humidity were measured, and further served as the data to verify the accuracy of the simulated results. The results show that the temperature and humidity were above 20 °C and 40% in the heating season, in accordance with the regulated low energy building standard (DB63/T1682-2018). According to the TRNSYS simulation, the hourly indoor temperature and relative humidity were generally in the range of 20–24 °C and 34–56%, respectively, in the heating season, with an energy demand of 16.1 kW h/(m2 year). Overall, the building performance meets the local low energy building standard (DB63/T1682-2018). Therefore, a passive building with integrated heating system assistance is feasible for pleasant indoor comfort on Qinghai-Tibetan Plateau. These findings could explore the application potential of low energy buildings in severe cold climate areas. [ABSTRACT FROM AUTHOR]

Abstract To relieve soil thermal accumulation and performance degradation over a long-time operation for ground source heat pump (GSHP) system in cooling-dominated area, a hybrid GSHP system with cooling tower (HGSHP) was proposed. The purpose of this paper is to study the performance and feasibility of HGSHP in Shanghai. Firstly, the simulation model of GSHP system for an office building was established by TRNSYS 17.0 and the reliability of simulation was validated by the measurement data. Then, one-year and ten-year variation of performance parameters of GSHP and HGSHP systems were calculated respectively and explored in depth. These results shown that, compared with GSHP system, the annual average electricity consumption of HGSHP system decreased by 6.40% and coefficient of performance (COP) increased by 7.12% during the first year of operation. Additionally, the outlet temperature of buried pipes was below 32 °C for HGSHP system during ten-year operation, while in GSHP system, the over-standard rate of outlet temperature of buried pipes could reach approximately 80% and soil temperature increased by 10.9 °C. These findings indicated that HGSHP system could provide a feasible solution for cooling and heating in hot summer and cold winter zones. Highlights • GSHP system for case building was evaluated by field measurement and simulation. • A cooling tower-assisted hybrid ground source heat pump system was proposed. • Performance parameters for these two systems for one and ten years were compared. • Feasibility and performance of this novel HGSHP system was confirmed. [ABSTRACT FROM AUTHOR]

To promote the application of renewable energy in low-energy buildings in Alpine regions, a solar-air source heat pump (SASHP) system was investigated based on a low-energy residential building in Xining City. First, a solar fresh air (SFA) heating system simulation model was established in TRNSYS software, and the reliability of the model was verified with measured values. In addition, based on the SFA heating system model, a SASHP system model was further realized. The operating characteristics of the SASHP system were explored in depth and compared with those of the single-ASHP system in the heating season. The results show that the SFA heating system model is reliable, with relative errors that can be controlled within 15%. The indoor average temperature (T ave) can be maintained from 16.13 to 19.61 °C. The SASHP system can leads to T ave fluctuations within the range of 21.4–22.9 °C, and the solar fraction can reach 55% in the heating season. Furthermore, the SASHP system can reduce energy consumption by 55.38% compared to the ASHP system; additionally, the COP of the SASHP system is 109.43% higher than that of the ASHP system, and the annual cost is 9.7% lower. Moreover, the SASHP system produces 55.48% less carbon emissions than the ASHP system. These results provide guidance for the application of SASHP systems in Alpine regions. [ABSTRACT FROM AUTHOR]