Dupe body heating and cooling

[Gurgel]

Dupes can heat and cool themselves and thereby their environment. But how much? For cooling, it seems to be somewhere around 180DTU/s in addition to cooling their self-heating (83.68 DTU/s) which places them at 2% of a Wheezewort in Hydrogen. For heating, it seems to be the 83.68DTU/s of self-heating the temperature info mentions. 

Is this correct? Does anybody have better numbers?

 

 

[Neotuck]

This reminds me of "The Matrix" for some reason

[impyre]

I did a bit of testing, and from what I can tell, dupes heat/cool their own bodies at a rate of 557.87 DTU/s. (The homeostasis value, the body's ability to heat/cool itself). This value does not affect the environment directly, it affects the dupe's temperature. Heat flows to/from the dupe at a rate specified by their thermal conductivity. Which is to say that the amount by which they affect their environment depends on specific heat and thermal conductivity of their environment. This is why water is almost always "cool" to them. Their low mass means that a small-ish tank of water could literally take all their body heat without warming up even a little. In order to measure/observe the heating/cooling effect of a dupe, you need to use a small container filled with a tiny about of a thermally reactive gas (hydrogen).

I used two tiles of 500 grams each of hydrogen. Starting temps for the cells were 110k, 160k, 210k, 260k, 310k, 360k, 410k, and 460k. I chose these values because a dupe's normal body temperature tries to stabilize at 37C, which is very approximately 310k. I wanted to see if homeostasis resulted in heating the room above the dupes desired temperature (like how if you're in a tight enclosed space you can easily get overheated). Turns out dupes are perfectly fine at 310k, and the room temp didn't change at alll.

The rate of thermal transfer depends on thermal conductivity between the dupe and the gas, and also on the amount of gas per tile. Higher pressures result in more thermal transfer per second. The transfer caps at -10 kDTU/s in cold environments and 9860DTU/s in hot environments. Bear in mind these are representative of heat transfer from the dupe's perspective, 9860 DTU/s heating coming from a hot environment, but from the environment's perspective, the dupe is providing 9860 DTU/s cooling. As always with gasses, there are a lot of variables and I found testing to be difficult. The problem is that with small amounts of gas, the temperature (and thus the rate of exchange with the dupe) changes rapidly. A dupe can cool a kilogram of hydrogen from 200C to a survivable temperature without dying (and in less time than it takes to suffocate). Since the temperature difference affects the rate of exchange with the environment, this value is constantly fluctuating and never the same, making it difficult to get reliable and consistent readings. When attempting to use more gas (a higher thermal mass means slower heating) the exchange rate with the environment is multiplied by the amount of gas. Twice the gas, twice the heat exchange (approximately). This had the effect of restricting the temperature range between the caps to a much smaller range. At the point where readings can be taken consistently and reliably, the environmental exchange rate caps out around +/- 100k on either side of 310K. Still, that's preferable if you feel like calculating thermal mass and finding the real transfer rate since you can actually get usable data from this. I really can't be bothered lol.

The 83.68 DTU/s is the duplicant's metabolic heating. Basically, in order to be comfortable, they have to be able to equalize this with their environment. Since this is hardly enough heat to really change the environmental temperature, all this means is that they prefer an environment slightly cooler than their body temperatures in order to be comfortable. In an ideal dupe environment, metabolic heating is exactly equal and opposite of environmental exchange rate. In a room at 310k, no heat transfer occurs because the room is the same temperature as the dupe's body temp. This means that 83.68 DTU/s builds up over time, or it would if the dupe didn't have the ability to self-cool.

The short version is, body heating is pretty broken. Not only can dupes magically cool themselves down (and are perfectly happy living at 37C, even though they clearly should be overheating) but homeostasis is either "on" or "off" and has a static rate of +/- 557 DTU/s.

 

 

As a short aside, and on a related note, you can see how thermal conductivity affects transfer between the dupe and their environment by checking how different gas types affect comfortable temperature (using the thermal tolerance overlay). Gray areas are temperature-neutral for the dupe, while blue areas result in body heat loss, and red areas result in heat retention (theoretically). You find that using chlorine allows dupes to comfortably be in more extreme temperature areas without the debuffs. They can go as low as -160C and as high as 135C without any ill effect or debuff.

[Sasza22]

How do clothes affect that? Only info they give is insulation thickness in cm. That`s telling us nothing.

[Gurgel]

4 hours ago, impyre said:

I did a bit of testing, and from what I can tell, dupes heat/cool their own bodies at a rate of 557.87 DTU/s.

[...]

The short version is, body heating is pretty broken. Not only can dupes magically cool themselves down (and are perfectly happy living at 37C, even though they clearly should be overheating) but homeostasis is either "on" or "off" and has a static rate of +/- 557 DTU/s.

Thanks, this is pretty much what I was looking for. My rough 180DTU/s estimate was from checking the comfort-zone indicator and checking at what heat transfer they become too hot or too cold for comfort. A lot more off than I expected. I also noticed some switching in the homeostasis and that the temperature-change numbers did not make sense when taken only in one moment. Basically a switching regulator (with a 557DTU/s heater and cooler) and the 83.68 DTU/s offset, which is easy to implement but a bit hard to follow. Explains it nicely though.