Sun lamp

Acquisition

It is constructed with 40 Steel in 330 ticks (5.5 secs) after Electricity has been researched.

Summary

A sun lamp consumes 2900 W of power from 06:00 to 19:12, the period where plants can grow. While online, it provides 100% light within a 5-tile radius. This allows crops like rice plant to grow in a roofed room. As the natural sun doesn't always provide 100% light at day, a sun lamp causes plants to grow somewhat faster. They also provide at least 30% light in a 13-tile radius, which is enough to prevent penalties for being in darkness.

Due to RimWorld's temperature mechanics, an enclosed room with a mostly complete roof is required to actually heat or cool an area. Lamps themselves give a marginal amount of heat, 3 heat per second.

Rain or snow on a powered sun lamp will cause short circuits and fires. A roof will prevent this.

Analysis

An efficient pattern to fit multiple sun lamps together. There are 10 empty tiles per sun lamp, half as many as in a simple grid pattern.

A sun lamp's main purpose is to create growing zones indoors, often called greenhouses. This allows plants to grow in the winter, when used with a heater. In extremely hot biomes, you might need coolers to grow during in the summer. Even in an "year-round" growing season, unpredictable events such as toxic fallout and volcanic winters can disrupt plant growth. Double-width walls provide more insulation against temperature changes, and potentially save on heater/cooler costs.

Solar flares will cut the power, so prepare a shelf with emergency wood to build campfires to keep the room temperature above -10 °C (14 °F) (below which most plants will rapidly die).

As they cannot be grown under roofs, trees such as pine, birch, saguaro or cocoa trees may not be grown in completely closed greenhouses. They may only be grown in greenhouses with roofs open in a grid pattern, and those leak a lot of temperature-controlled air.

Power

If you have biofuel refineries available, you can use food produced by hydroponics to fuel chemfuel generators to help power the greenhouse array. This is so efficient that it violates thermodynamics, and leaves you with spare food for your colonists as well.

As sun lamps turn off at night, they consume an average of -1595 W⋅Days. Batteries can be used to average out power usage. However, batteries only take in energy at a 50% rate, effectively meaning double the power is required at night, for an average required consumption of -1957.5 W⋅Day.^[Verify]

Otherwise, 2 solar generators are roughly enough to power a single sun lamp, not counting any hydroponics basins.

Hydroponics

96% hydroponics, tightly nested together.

Sun lamps can be used in ordinary soil. But as the power cost of a sun lamp of very high, building a room of hydroponics basins helps with making the most of the limited growing area per lamp. Hydroponics will boost soil fertility to 280%, twice that of rich soil. However, each basin costs 100 W and only covers 4 tiles. Due to how the light radius forms, only 96% of a lamp's area can be used in hydroponics at a time.

A sun lamp supports 100 tiles for 2900 W of power, or -29 W / tile. In contrast, a full hydroponics setup consumes -45.8 W / tile, but gives 280% growth for 96 of the tiles. Therefore, a "true" -16.36 per tile can be reached with hydroponics, compared to regular soil.

However, the 24 hydroponics basins would cost 2400 Steel, 24 Components. In contrast, 2 solar generators, practically enough to power another sun lamp, would only cost 200 Steel, 6 Components. If your only goal is to grow crops during the winter, then sun lamps are more resource efficient. However, the lamps would end up taking up more space. Hydroponics are an option if space is an issue; larger fields can be difficult to walk to, let alone protect.

Version history

0.17.1546 - Now turn themselves off when plants are resting.

Architect

Furniture: Animal bed • Animal sleeping box • Animal sleeping spot • Bedroll (Double) • Plant pot • Sculptures (Small, Large, Grand, Terror ) • Sleeping spot (Double, Baby ) • Stool • Table (1x2, 2x2, 2x4, 3x3) • Torch lamp • Wall torch lamp • Wall lamp • Animus stone • Darktorch • Fungus darktorch • Crib
Complex Furniture: Armchair • Bed (Double) • Bookcase (Small) • Couch • Dining chair • Dresser • End table • Royal bed • Shelf (Small) • Brazier (Darklight ) • Drape • Grand meditation throne • Meditation throne • Slab bed (Double) • Baby decoration • Blackboard • School desk • Toy box
(research): Flood light • Hospital bed • Standing lamp • Sun lamp • Bonsai pot
(uncraftable): Urn • Blood torch