A comparative study of radiant floor heating strategies for passive house in severely cold regions: A case study of Harbin

This study explores the efficient heating strategy for passive houses in severely cold climates to improve the indoor thermal environment. Intermittent heating strategies based on indoor temperature to radiant floor heating system are applied and various heating methods under three heating strategies for passive houses are simulated. We proposed three metrics to rate the effectiveness of heating strategies: the indoor comfort rate (ICR), the physical comfort rate (PCR), and the thermal response coefficient (TRC), which are integrated to evaluate the performance of heating strategies comprehensively. It is shown that outdoor temperature fluctuation has little influence on the choice of heating strategy for passive houses. Furthermore, the short-interval heating strategy's ICR and PCR are above 90 %, and the TRC is above 0.2 h−1, demonstrating better performance than the continuous low temperature and long interval heating strategies. The results suggest the adoption of a short-interval heating mode for passive houses, with a suggested inlet water temperature of 60 °C and an indoor temperature control range of 22–26 °C. The study compares and analyzes three control strategies (continuous low-temperature heating, long interval heating, and short-interval heating), providing a reference for selecting appropriate heating strategies under different usage scenarios.