Thermal Brownian heat pump with external and internal irreversibilities Congzheng Qi, Lingen Chen, Yanlin Ge, Wenhao Yang and Huijun Feng Eur. Phys. J. Plus, 137 9 (2022) 1079 Published online: 23 September 2022 DOI: 10.1140/epjp/s13360-022-03287-1