Ethanol

Ethanol is a liquid element used as both a fuel and an industrial fluid. It is produced in an Ethanol Distiller from Lumber, and it also appears as an intermediate in several farming and power-generation chains. Because it has useful thermal properties and can be made from renewable lumber, it is especially relevant in mid-game colony setups.

A Petroleum Generator can burn Ethanol or Petroleum to generate power. Its consumption and output are:

• 2 kg/s Ethanol or Petroleum
• 2 kW Power
• 500 g/s Carbon Dioxide
• 750 g/s Polluted Water

This makes Ethanol a viable backup fuel if a colony is already processing lumber. It is not as efficient as simply using the fuel for other purposes, but it is convenient when a colony wants to turn wood into electricity while also producing Polluted Water as a byproduct.

Ethanol is also a plant input. Nosh Sprout domestic growth requires 20 kg/cycle Ethanol irrigation, and Plume Squash Plant growth can also be supported with Ethanol when grown in a Hydroponic Farm. That makes Ethanol part of late-resource farming loops rather than only a fuel. If a base is already running an Arbor Tree lumber economy, Ethanol production can feed both power and specialized crops.

From a thermal standpoint, Ethanol is a very flexible liquid. It has good heat capacity, very low heat conductivity, and a wide temperature range of 192°C, which makes it a useful insulating liquid, especially in lower temperature ranges. Its freezing point is extremely low at -114°C, so it is often a strong choice for mid-game freezer coolant before Super Coolant becomes available. It is, however, less heat-efficient than water-based liquids in raw specific heat capacity, so more energy is required to cool it per degree. That means its usefulness usually comes from its low freezing point rather than from exceptional efficiency per unit of cooling power.

Compared with other common coolants, Ethanol is:

• about 12% more power-efficient than Naphtha
• 40% better than Petroleum
• 46% better than Crude Oil
• more than twice as efficient as Hydrogen after accounting for Thermo Aquatuner and Thermo Regulator differences

It is still less efficient than Polluted Water, but Polluted Water leaves very little safety margin between the Deep Freeze threshold and its own freezing point. Brine is a little safer in that respect, though it is harder to obtain.

Ethanol can also serve as a heat-transfer medium once it becomes gas. At around 80°C, it turns into gas, and in that state its heat behavior is only slightly worse than Hydrogen, making Ethanol gas a respectable heat conductor at temperatures above 100°C. Because of the specific heat difference between the liquid and gas states, repeatedly boiling and condensing Ethanol can be used as a heat deletion method.

Its thermal behavior makes Ethanol particularly useful for Sleet Wheat farms, where its low conductivity helps maintain sub-zero temperatures and Radiant Liquid Pipe can compensate for slow heat exchange. The low conductivity also makes spills easier to mop up, since accidental puddles spread heat more slowly than many other liquids.

Ethanol production itself comes from lumber processing. An Ethanol Distiller converts:

• 1 kg/s Lumber
• into 500 g/s Ethanol
• 333.33 g/s Polluted Dirt
• 166.67 g/s Carbon Dioxide

That means Ethanol is best treated as part of a wood-processing loop: Arbor Tree lumber can become fuel, coolant, or crop irrigation, depending on the colony’s needs.