Construction of a High Temperature (~ 200 °C) Oil Pump for Solar Thermal Energy Storage System for Cooking Applications

Abstract

In this study, a positive displacement (PD) oil pump capable of operating at temperatures about 200 °C was constructed using locally available materials. The oil pump was tested to circulate pre-heated refined sunflower oil in Thermal Energy Storage (TES) tank comprising of an oil only and rock pebble-oil system and cooking application. The oil pump was constructed of harden steel and mild steel materials driven by AC/DC electric motor rated 8000 rpm. Standard gear teeth cutting tool was employed to produce the spurs and the pumps’ speed was varied using variable AC transformer connected to 220V AC main source. The performance of the pump was evaluated for maximum temperature during charging oil tank where the pump circulated hot oil through it and a temperature of about ~ 215 °C was achieved. In addition, when the oil pump was used to charge 5.5 litres of refined sunflower oil in TES tank by heat extraction through a boiler, an average temperature profile of 190 °C was achieved in 3 hours compared to the 74 °C attained by thermosiphoning in 6 hours of charging in the studies done by Mawire (2009). In addition, the TES cooking application fabricated demonstrated cooking of local foods such as bean and rice with a comparable cooking time. It was observed that the integration of the TES system with high temperature pump improved the performance of TES charging efficiency.

Keywords: High temperature; positive displacement pump; hard steel; heat extraction