The maximization of oscillating heat pipe (OHP) has important significance on OHP based large-scale thermal energy storage (TES) system. In order to understand the thermal performance of OHP with long heat-transport distance for thermal energy storage (TES) application, a large-OHP testing platform was constructed. The influence of working medium type, heating load, cooling condition on the thermal efficiency, thermal resistance and effective thermal conductivity of OHP were investigated and analyzed. The results mainly showed that the OHP with self-rewetting fluid (SRWF) has greater heat transfer limit and can work normally under larger heating load compared to that with water or ethanol as working medium. The OHP with filling ratio (FR) of 40-80% can endure higher heating load compared to the case of FR = 30%. It can be concluded that the best FR is about 40% under large heat load (the effective thermal conductivity reaches 5676 W m(-1) degrees C-1 at 700 W). The SRWF based OHP with long heat-transport distance in this paper has lower thermal resistance and larger heat density compared to those of some other research groups. (C) 2016 Elsevier Ltd. All rights reserved.