Thermal Expansion

Overview

Thermal Expansion is the core "industrial" module of the Thermal Series, a collection of mods that has been a cornerstone of modded Minecraft for nearly a decade. This module provides the machines, power generators (Dynamos), energy storage, and utility devices that form the backbone of any Thermal-based setup. The mod uses Redstone Flux (RF) as its energy system, which has become the standard power unit across most tech mods.

The mod adds 16 machines for processing resources, 6 Dynamos for generating RF power, 4 types of storage blocks, and over a dozen utility devices. Every machine and Dynamo can be upgraded through 5 tiers (Basic, Hardened, Reinforced, Signalum, and Resonant) and customized with Augments that change how they behave. You can browse every item and recipe this mod adds using the tabs at the top of this page.

Thermal Expansion requires Thermal Foundation (for ores, alloys, and base materials) and CoFH Core as dependencies. The other Thermal modules (Dynamics for pipes, Innovation for tools, Cultivation for farming) are optional but complement the experience.

Power Generation: Dynamos

Dynamos are the power generators of Thermal Expansion. All six Dynamos produce Redstone Flux (RF) and output it from the coil end (the smaller end of the block). They all share the same 5-tier upgrade path and augment system, and each has a base output of 40 RF/t, with the exception of the Gourmand Dynamo at 10 RF/t. Dynamos automatically adjust their output based on internal energy storage, so they will not waste fuel when connected machines are full.

Steam Dynamo

The most accessible Dynamo and your likely first power source. It burns solid fuels (Coal, Wood, Charcoal) and consumes Water to generate steam internally. It produces 40 RF/t at base. You will want to pair it with an Aqueous Accumulator to provide a constant Water supply. With the Boiler Conversion augment, it can output Steam directly instead of RF, and with the Turbine Conversion augment, it can consume Steam from an external source.

Magmatic Dynamo

Burns Lava and other hot fluids to produce 40 RF/t. This is a favorite early-mid game option because large Lava pools in the Nether provide essentially unlimited fuel. Pipe Lava in with Fluiduct from Thermal Dynamics or any compatible fluid pipe and you have a reliable, hands-off power source.

Compression Dynamo

A dual-fluid Dynamo that requires both a liquid fuel (like Refined Fuel, Tree Oil, or Liquifacted Coal) and a Coolant. It produces 40 RF/t and is very efficient when supplied with high-energy fuels. The Coolant can be Water, Gelid Cryotheum, or other cooling fluids, each with different efficiency multipliers.

Reactant Dynamo

Combines a solid reactant item with a fluid reactant to generate 40 RF/t. Common combinations include Blaze Powder with Destabilized Redstone, or Gunpowder with Blazing Pyrotheum. This Dynamo excels when you have access to exotic fluids from the Magma Crucible.

Enervation Dynamo

Extracts energy from charged items and Redstone-related materials. Feed it Redstone Blocks, Redstone, or charged RF items to generate 40 RF/t. With the Disjunctive Extraction augment, it can consume enchanted items for even more power, making it useful for disposing of unwanted enchanted gear from mob farms.

Numismatic Dynamo

Burns coins and currency items for 40 RF/t. With the Lapidary Calibration augment, it can instead consume Gems (Diamonds, Emeralds, Lapis Lazuli, Quartz) for very high RF output per item. This can be an expensive but powerful late-game power option.

Machines: Resource Processing

Thermal Expansion includes 16 machines, each designed for a specific type of processing. All machines consume RF power, and most operate at a base of 20 RF/t (with the Magma Crucible and Energetic Infuser being exceptions at 40 RF/t). Every machine supports the same tier upgrade system, side configuration, Redstone control, and augment slots.

Redstone Furnace (20 RF/t)

A direct replacement for the vanilla Furnace that runs on RF instead of fuel. It smelts everything a normal Furnace can, but faster and without needing a constant supply of Coal. With augments, it can be specialized into a Food-only furnace (Trivection Chamber), an Ore-only furnace (Flux Anodizers), or a Pyrolysis unit that produces Creosote Oil as a byproduct.

Pulverizer (20 RF/t)

The most important machine in your early setup. It grinds ores into Pulverized metals (two per ore for effective ore doubling), and many recipes also produce secondary byproducts. Pulverizing Iron Ore, for example, gives a chance of Pulverized Nickel as a secondary output. The Tectonic Initiator augment uses Tectonic Petrotheum fluid to boost secondary output chances.

Induction Smelter (20 RF/t)

The key to alloy creation. The Induction Smelter combines two input items and produces alloy ingots. This is how you create Invar (2 Iron + 1 Nickel), Bronze (3 Copper + 1 Tin), Electrum (Gold + Silver), Constantan (Copper + Nickel), and more advanced alloys like Signalum and Enderium. It also processes ores with Sand as a flux, yielding extra ingots and Rich Slag as a secondary.

Sawmill (20 RF/t)

Processes Wood Logs into Planks more efficiently than hand-crafting (6 Planks per Log instead of 4), and produces Sawdust as a secondary output. Sawdust is useful for creating Compressed Sawdust and other recipes. It can also break down wooden items into their plank components.

Compactor (20 RF/t)

Presses materials into plates, coins, or gears depending on its mode. In Plate mode (default), it creates metal plates needed for many advanced recipes. The Numismatic Press augment enables Coin mode for minting coins, and the Gearworking Die augment enables Gear mode for producing gears without a crafting recipe.

Magma Crucible (40 RF/t)

Melts solid items into their liquid forms. Cobblestone becomes Lava, Redstone becomes Destabilized Redstone, Glowstone Dust becomes Energized Glowstone, and Ender Pearls become Resonant Ender. These fluids are essential ingredients for advanced alloys and the Reactant Dynamo. The Crucible draws 40 RF/t, making it one of the more power-hungry machines.

Fractionating Still / Refinery (20 RF/t)

Distills fluids into refined products. Its primary use is converting Crude Oil (from Thermal Foundation world gen) into Refined Fuel, which is an excellent fuel source for the Compression Dynamo. It can also produce Naphtha and other fluid byproducts.

Fluid Transposer (20 RF/t)

Fills or empties fluid containers. Use it to fill Buckets, bottles, and other fluid-holding items, or to extract fluids from them. It is also used in many crafting recipes that require infusing an item with a specific fluid, such as creating Florbs or treating various materials.

Energetic Infuser / Charger (40 RF/t)

Charges items that store RF energy, such as Flux Capacitors, powered tools, and Energy Cells in item form. It draws 40 RF/t and is essential once you start using RF-powered tools from Thermal Innovation or other mods.

Phytogenic Insolator (20 RF/t)

An automated farming machine that uses Water and RF to grow seeds and saplings into their harvest outputs. Feed it Wheat Seeds and it produces Wheat plus bonus seeds. It works with all vanilla crops and many modded ones. Adding Phyto-Gro (Thermal Foundation's fertilizer) as a catalyst significantly boosts output and secondary drop chances.

Other Machines

The remaining machines serve more specialized roles. The Centrifugal Separator (20 RF/t) splits composite items into their components, like separating Magma Cream into Blaze Powder and Slime Balls. The Sequential Fabricator (20 RF/t) automates crafting table recipes using RF. The Alchemical Imbuer (20 RF/t) brews potions automatically. The Arcane Ensorcellator (20 RF/t) applies enchantments to items using Books and Lapis Lazuli. The Glacial Precipitator (20 RF/t) creates Snow, Ice, and Packed Ice from Water. The Igneous Extruder (20 RF/t) combines Lava and Water to produce Cobblestone, Stone, or Obsidian without mining.

Devices: Passive Utility Blocks

Devices are utility blocks that operate without RF power. They use a Device Frame instead of a Machine Frame and perform passive or semi-passive functions. Thermal Expansion adds 13 devices, each filling a specific niche in your automation setup.

Aqueous Accumulator

Generates Water passively when placed adjacent to Water source blocks. Create an infinite Water source (2x2 Water pool) next to it and it will fill its internal tank at 4,000 mB per cycle. Even without adjacent Water, it slowly generates 80 mB per cycle. This is your primary Water supply for Steam Dynamos and the Phytogenic Insolator. It requires no power to operate.

Nullifier

Destroys any items or fluids piped into it. Useful for getting rid of unwanted byproducts in automated systems, like excess Cobblestone from a quarry or secondary outputs from machines you do not need.

Arboreal Extractor

Extracts fluid from adjacent trees (Resin, Sap, or Latex depending on the tree type). Place it next to a log with leaves and it will slowly accumulate fluid in its 8,000 mB internal tank. Adding Phyto-Gro as a catalyst boosts its production rate. The output fluids can be used as fuel or in other recipes.

Other Devices

The Aquatic Entangler fishes automatically when placed near Water (7,200 ticks between catches). The Thermal Mediator (Heat Sink) speeds up adjacent machines using Coolant fluid. The Item and Fluid Buffers provide temporary storage with configurable input/output sides. The Factorizer converts between storage blocks and individual items (9 Ingots to 1 Block and back). The Creature Encaptulator (Mob Catcher) captures mobs into Morbs for transport. The Vacuumulator (Item Collector) picks up dropped items in a radius, and the Insightful Condenser (XP Collector) absorbs nearby experience orbs into a Tome of Knowledge.

Storage Blocks

Thermal Expansion provides four specialized storage blocks, all of which support the 5-tier upgrade system. Their capacity multipliers follow the pattern: 1x (Basic), 4x (Hardened), 9x (Reinforced), 16x (Signalum), 25x (Resonant). The Holding enchantment can further increase their capacity.

Energy Cell

Stores Redstone Flux for later use. The base capacity is 2,000,000 RF with a transfer rate of 1,000 RF/t input and output. At Resonant tier, this scales to 50,000,000 RF capacity and 25,000 RF/t transfer. The transfer rates can be independently configured for input and output. Energy Cells retain their stored energy when broken and picked up.

Portable Tank

Stores a single type of fluid. Base capacity is 20,000 mB (20 Buckets), scaling up to 500,000 mB (500 Buckets) at Resonant tier. Like Energy Cells, Portable Tanks retain their contents when broken. They can be placed adjacent to each other and will transfer fluids between connected Tanks.

Cache

Stores a massive quantity of a single item type. Base capacity is 20,000 items, scaling to 500,000 at Resonant tier. Right-click to insert items from your hand, left-click to extract. Sneak-right-click to lock the Cache to a specific item type so it will not accept anything else, even when empty. This is incredibly useful for sorting systems.

Strongbox

A secure, upgradeable Chest. Unlike the Cache (which stores one item type in bulk), the Strongbox provides multiple inventory slots like a regular Chest. It retains its contents when broken and can be secured to prevent other players from accessing it.

Upgrade Tiers

Every machine, Dynamo, and storage block in Thermal Expansion can be upgraded through five tiers. Each tier increases the block's energy storage (and therefore processing speed), adds augment slots, and for storage blocks, dramatically increases capacity. Upgrades are applied either through Upgrade Kits (which advance one tier at a time) or Conversion Kits (which jump directly to a specific tier).

The five tiers are Basic, Hardened (requires Invar), Reinforced (requires Electrum and Hardened Glass), Signalum (requires Signalum Ingots), and Resonant (requires Enderium Ingots). Alternatively, machines can be upgraded using classic recipes that surround the machine with the appropriate ingots in a Crafting Table. The number of augment slots increases from 0 at Basic to 4 at Resonant tier.

Augments

Augments are items installed into the augment slots of machines and Dynamos to modify their behavior. Some augments are universal (usable in any machine), while others are machine-specific and fundamentally change how the machine operates. You can mix and match multiple augments, though you cannot install duplicates of the same augment.

Universal Machine Augments

The Auxiliary Reception Coil increases a machine's power draw by 10 RF/t, which directly increases processing speed since machines process faster with more stored energy. Multiple coils stack. The Auxiliary Sieve reduces secondary output chances by 15% but adds 10% to the energy modifier, useful when you only care about primary outputs. The Nullification Chamber destroys excess secondary outputs entirely, preventing machines from halting when secondary output slots fill up. This is essential for automated setups where you do not care about byproducts.

Dynamo Augments

Dynamos have their own augment categories. The Auxiliary Reaction Chamber increases power generation but reduces fuel efficiency. The Fuel Catalyzer (Multi-cycle Injector) improves fuel efficiency but does not change output rate. Balancing these two augments lets you trade off between raw power output and fuel economy depending on whether your fuel supply is limited or abundant.

Specialization Augments

Many machines have unique augments that change their function entirely. The Compactor's Numismatic Press augment switches it from plate mode to coin minting. The Furnace's Trivection Chamber locks it to food-only recipes but increases speed. The Smelter's Pyrotheum Injection augment uses Blazing Pyrotheum fluid to reduce energy costs by 50% but cuts secondary outputs by 30%. These specializations let you build purpose-built machines for specific tasks in your automation network.

Side Configuration and Automation

One of Thermal Expansion's most powerful features is the side configuration system shared by all machines, Dynamos, and storage blocks. Every block has six configurable faces (top, bottom, left, right, back, and front) that can be independently set to input, output, both, or disabled.

Input sides are shown in blue, and output sides are shown in orange. Machines with multiple input or output slots use different colors to distinguish which slot each face connects to. For example, the Pulverizer has a primary output (Pulverized metal) and a secondary output (byproduct), and you can route each to different faces.

The key settings to remember are Auto-Input and Auto-Output. Auto-Input causes the machine to pull items from adjacent inventories on input-configured sides. Auto-Output pushes finished products to adjacent inventories or machines on output-configured sides. Without these toggles enabled, items will not move automatically even if the sides are properly configured. This means you can chain machines directly without any pipes at all: set the output side of one machine facing into the input side of the next, enable Auto-Output on the first and Auto-Input on the second, and items flow seamlessly between them.

Key Alloys and Materials

Thermal Foundation (the companion mod) adds several ores and alloys that are critical for Thermal Expansion. Understanding these materials and how to create them is essential for progressing through the upgrade tiers.

The early-game alloys are created in the Induction Smelter. Invar (2 Iron + 1 Nickel) is used for Hardened tier upgrades and the Magmatic Dynamo. Bronze (3 Copper + 1 Tin) and Constantan (Copper + Nickel) are used in various machine recipes. Electrum (Gold + Silver) is needed for Reinforced tier upgrades.

The advanced alloys require fluids from the Magma Crucible, making them mid-to-late game materials. Signalum is created from Copper and Destabilized Redstone (molten Redstone). Lumium is created from Tin and Energized Glowstone (molten Glowstone). Enderium is the top-tier alloy, created from Lead, Tin, and Resonant Ender (molten Ender Pearls). These alloys unlock the Signalum and Resonant upgrade tiers.

Recommended Processing Chains

The real power of Thermal Expansion is chaining machines together into automated processing lines. Here are the most useful chains to build.

Ore Doubling Line

The simplest and most important chain. Feed ores into a Pulverizer, which outputs two Pulverized dusts per ore. Route the dusts into a Redstone Furnace, which smelts each dust into an ingot. The result is two ingots per ore instead of one. Secondary outputs from the Pulverizer (like Pulverized Nickel from Iron Ore) can be routed to a separate Chest or fed into another Redstone Furnace.

Alloy Production

Set up an Induction Smelter with two input sources: one for each component of the alloy. For Invar, feed Iron Ingots and Nickel Ingots. The Smelter combines them into 3 Invar Ingots without the material loss of crafting-table recipes. For advanced alloys, you will also need a Magma Crucible to produce the required fluids, plus a Fluid Transposer to infuse items.

Infinite Obsidian

Place an Igneous Extruder with a Water and Lava supply (Aqueous Accumulator for Water, Magmatic Crucible or Nether pump for Lava). Set it to Obsidian mode and it produces Obsidian blocks indefinitely without the slow process of mining them manually.

Configuration

Thermal Expansion is highly configurable. Client settings are in the thermal-client.toml file in the /config folder. Server settings (which affect gameplay) are in thermal-server.toml inside /saves/WORLD_NAME/serverconfigs. Copying this file to /defaultconfigs will apply those settings to all newly created worlds.

Notable configuration options include the ability to adjust the base power consumption (BasePower) of every machine individually (range 10-5000 RF/t), toggle individual machines and Dynamos on or off, enable or disable classic upgrade recipes, and configure storage block base capacities. The SmallStorage option reduces machine internal energy storage, making power management more challenging for players who want a harder experience.