Determining Operating Parameters of an Electric Furnace for Casting of Bronze Age Replicas

Abstract

In previous work, a small electric furnace with a capacity of 3.5 kg of liquid copper, capable of reaching temperatures up to 1200 °C, and with nominal power input of 2.1 or 6.2 kW at 230 V was designed and constructed. The purpose of this furnace was to melt metals for casting replicas of historical weapons, tools, and jewellery from the Bronze Age. The theoretical operating parameters, such as electric energy consumption and the time required to melt the batch of metal, were derived from the design calculations. This study focuses on the experimental determination of the furnace’s operating parameters. Experiments were conducted to determine surface heat losses from the furnace, as well as electric energy consumption and the time required to melt aluminium and copper batches of various quantities during cold starts and continuous furnace operation. The data from these experiments were subsequently analysed to determine the thermal efficiency of the furnace and the cost of energy consumed for melting a batch under given conditions. The experimental results indicate that the furnace does not reach a steady state regarding heat transfer within the time required for melting a batch during cold starts. As a result, the surface heat losses are lower than initially calculated in the theoretical analysis. This leads to shorter required melting times, lower energy consumption, and lower energy costs for the batch compared to design values.

Keywords

• electrical furnace
• energy consumption
• energy efficiency
• replica casting