Kiln

Kiln is a refinement building used to process bulk materials into more useful products without duplicant operation. Its recipes include turning coal into Refined Carbon and clay into Ceramic, and it can also be used to refine Metal Ore into Refined Metals. It is one of the few production buildings that can be fully automated with an Auto-Sweeper, which makes it easy to integrate into sealed industrial setups.

The Kiln always outputs its products at 80 °C, regardless of the input material temperature, surrounding environment temperature, or the Kiln’s own temperature. Both listed recipes produce 100 kg of output from 125 kg of input, or from a 100 kg + 25 kg input combination. Because the output mass is lower than the input mass, the building can act as a net heat-negative process when run on sufficiently warm inputs. For coal-to-Refined Carbon, the input coal must be above about 9.6 °C for the process to be heat-negative; for clay-to-Ceramic, both inputs need only be above about -2.68 °C.

In practice, the Kiln is especially useful for resource conversion and heat management. It has no overheat temperature, and it exchanges heat only with the surrounding gas, not with the floor beneath it, its contents, the wire attached to it, or the duplicant delivering materials. That makes it viable even in a vacuum, where it can be used to reach very high temperatures without needing rocket exhaust gases or late-game materials. This is useful for improving the efficiency of Glass or Petroleum production, for heating solid clay or coal directly into Ceramic or Refined Carbon, and for producing Liquid Steel for high-temperature processes.

A Kiln can also be placed in a sealed Steam room and supplied by Auto-Sweepers and Conveyor Rails. In that setup, it can delete enough heat that the steam turbine can recover some power, although this is far less efficient than a Coal Generator and usually does not offset the power cost of the automation. The arrangement is mainly worthwhile because Kilns are often needed anyway; if the heat is not required elsewhere, putting them in steam maximizes resource return.

• Can be fully automated with Auto-Sweepers.
• Has no overheat temperature.
• Can refine Metal Ore into Refined Metals.
• Produces a distinctive sound and has a sprite resembling bagpipes when active.