What you learn today
- Convection or radiation
- A radiator as a heater
- Gas-to-gas heat exchanger
A radiator is not a cooler. It is a piece of pipe with a lot of surface, and heat always flows from warm to cold. Whether it cools or heats is decided only by what is warmer: the gas in the pipe or the surroundings.
Convection or radiation
| Prefab | Works by | fits for |
|---|---|---|
StructurePipeRadiator | convection | rooms and planets with atmosphere |
StructureMediumConvectionRadiator | convection | atmosphere |
StructureMediumRadiator | radiation | vacuum (moon, space) |
StructureLargeExtendableRadiator | radiation | vacuum; heats up strongly when turned to the sun |
Convection needs air that carries the heat away. In a vacuum only radiation is left. On a planet with an atmosphere you therefore use the convection variants.
The radiator as a heater
If the loop runs colder than the surroundings, the radiator takes in heat – it heats the loop. On Mars that rarely happens, because outside is usually colder than any loop. On Vulcan it is the normal case: it is 127 °C there even at night. A radiator on Vulcan only cools a loop that is even hotter.
A digital valve in front of the radiator turns it into a switch: gas may only pass when the radiator works in the wanted direction.
sub cools loop outside
sgt cools cools MARGIN # loop clearly warmer: radiator cools
sbn VALVE HASH("Radiator") On coolsGas-to-gas heat exchanger
A heat exchanger links two separate pipe networks. The heat passes from the warmer to the colder gas, the gases themselves do not mix. That way you can, for example, cool breathing air with CO₂ from outside without bringing the CO₂ into the base. Watch out when building: in the game the prefab is called StructureHeatExchangerGastoGas – with a lower-case “to”. There are also counterflow heat exchangers (StructurePassthroughHeatExchangerGasToGas).
A missing reading must never open the valve. Comparisons with NaN give 0 – that helps here. But select with NaN as its condition picks the first value, because NaN is not 0. So turn the lever value into a clean 0 or 1 first with sgtz heat heat.
The small gap of 2 K keeps the valve from rattling when the temperatures are almost equal. It works like a narrow dead band.
Exercise
Task
A digital valve “Radiator” lets gas from the loop (analyzer “Kreislauf”) through a radiator outside (sensor “Aussen”). The lever “Heizen” picks the goal: 0 = cool the loop, 1 = warm the loop.
- Cooling: valve open when the loop is more than 2 K warmer than outside
- Warming: valve open when outside is more than 2 K warmer than the loop
- Lever missing: cool. Analyzer or sensor missing: valve shut
Hints
Hint 1
Clean the lever first: sgtz heat heat turns NaN into 0.
Hint 2
Two comparisons: sub + sgt with MARGIN for “radiator cools” and “radiator warms”.
Hint 3
select open heat warms cools picks the right one – then to the valve's On.
Quiz
4 questions. You pass from 60 % – the server does the grading.
Complete the day
- Passed the simulator exercise
- Passed the quiz with at least 60 %
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