Heat is a form of energy that is all around us. There’s heat from the sun (solar thermal) and from the earth (geothermal) but for this post, I want to talk about industrial heat - heat that is a byproduct of manufacturing, refining, smelting, generating electricity, etc. - and its uses.

20-50% of primary energy input to US industrial facilities is lost as heat, which equals 5­ to 13 quadrillion Btu per year of unused energy (US DOE) | (EIA). For perspective, that’s somewhere between the entire primary energy consumption of the countries of Turkey and Germany (EIA). For simplicity, let's just say it's equivalent to Italy's 7.2 quadrillion Btu of energy consumed across its entire economy, including planes, trains, automobiles, power generation, and industrial consumption.

While some waste heat losses are inevitable and unavoidable, much of this heat can be captured and used. Many facilities around the world can increase their overall efficiency by installing waste heat recovery technologies. Once the heat is recovered, there are 3 primary options for putting it to more efficient use:

1. For heating (e.g. fuel pre-heating, space heating nearby buildings, heating water for purification, etc.)

2. For cooling (e.g. air conditioning or refrigeration with absorption chillers)

3. For generating electricity (e.g. rankine cycle, organic rankine cycle, and thermoelectrics all generate electricity from heat)