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Generating heat by freezing water.


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Hello, I noticed a huge SHC difference between Ice and Water after reading the following topic and tried to come up with a system producing heat by freezing water : 

 

 

Here it is

Spoiler

HotMrFreeze.gif.7579f7bbeecb01eba3bfb63e0456324a.gif

 

It's clearly not optimal and I have no idea of how much DTU/s it can produce but it does generate heat.

There is a layer of ethanol to insulate a bit the hot granite tiles from the alternating Vacuum/Water behind the mesh tiles and to melt the ice at a decent rate.

Packets of supercoolant bypass the aquatuner when above -80°C making the granite tiles about 70°C so the ethanol doesn't evaporate.

Mesh tiles are actually needed else the ice packets tend to think they're still in the vacuum after falling, and literally can't melt.

Metal floor is for evacuating the excess heat and putting it in a steam chamber.

Some screenshots of temperature evolution 

 

Cycle 34 

Spoiler

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End of cycle 35 all the water turned into steam

Spoiler

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This specific system needs 450-500kJ per cycle and recovers 45-50kJ with the steam turbine.

Hope you guys enjoyed and find a use for this; I don't know if it's more power efficient than a tepidizer or simply pointless =)

I can't wait for you guys to optimize it, here are the variables one can play with : 

-Mass of water on the upper layer (currently 100kg/tile)

-Material and mass of the bottom layer; the ethanol isn't a key aspect and can be replaced with another liquid/medium

-Material and type of tiles between the AT and the freezing room, currently granite tiles but igneous tiles did work quite well, insulated granite wasn't great.

-Temperature bypass of the AT

-drywall behind the bootom floor, I think it helped having an igneous backwall but not sure.

 

NB : a rough estimate put me at 300DTU/W, is my math totally wrong?

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15 hours ago, DonDegow said:

SHC difference between Ice and Water

When you freeze water and then melt the resulting ice, you definitely gain thermal energy. I played with this for a few hours a couple weeks ago. I'm pretty sure you could use the numbers found there to calculate the heat added (though you'll need to do some debug testing to get exact temps on a few things).  You definitely gain thermal energy through this process.

15 hours ago, DonDegow said:

There is a layer of ethanol to insulate a bit the hot granite tiles from the alternating Vacuum/Water behind the mesh tiles and to melt the ice at a decent rate.

I do love this design for melting/freezing.  Nicely conceived,

15 hours ago, DonDegow said:

Hope you guys enjoyed and find a use for this; I don't know if it's more power efficient than a tepidizer or simply pointless =)

I can't wait for you guys to optimize it,

I did enjoy it. If the only real heat added is the phase change shenanigans, then we generate the most heat the faster we can can cycle between phases. Sounds like a fun project which I might join (my hydrodynamics series is on hold for a while). 

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1 hour ago, DonDegow said:

a more complex and controlled system that may be more efficient.

This will freeze your water and deposit the ice completely outside of your freezer. :) @Tonyroid, I'm using a solid-liquid bypass, inspired from your volcano tamer. 

icemaker.thumb.png.87cf90119b8479ed572fa9751f8decdf.png

Attach the input side to an escher waterfall, and you can ramp up the input water to 125kg/s. Attach liquid pipes to the bottom region to maintain a low temp (increase the bottom region to 3 tiles wide of coolant if needed). 

To avoid the 20kg/s solid transfer rate (from conveyors), use a mech door to push the ice sideways into your heating region, then let the water fall off that region and cycle back to the top (escher waterfall) to repeat. No power needed for material transfer/separation, and then we can let aquatuners keep a sufficient temperature differential, and move the excess heat out.  

The excess heat moved out will scale linearly with the amount of liquid you have. A counter current heat exchanger might get you the ability to remove most of the cost of moving the extra heat to the turbine (one efficiency).  Another efficiency comes in how little power you can use to keep the pressure differential sufficient to rapidly freeze, and then melt, large quantities of water. Sounds very fun.

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17 minutes ago, DonDegow said:

Damn, that looks promising

This contraption melted 500kg of liquid, and the liquid left at 272.5K (so the amount of extra heat added was so small it did not show). 

melter.png.778c5ad3951443006d4efc4858502ddd.png

There are 30g of crude, and the ice melts on the metal plate.  The petro is where you add your heat. The water to the right is 500kg of 272.5K, ready to refreeze, water. Escher waterfalls, or door pumps, can get these two contraptions cycling, power free.  I ideas to improve each process (use the magma dropper cooling plate for freezing, and a 3 door trap with instant wisking to keep water away from the melter).  Gonna try those later today.   Hope you get something fun going. 

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I built this but it doesn't appear to have a benefit over my simpler system, the AT runs less often but the phase changes are occuring really slowly...

Weight plates are linked together to doors near the cold room and to a not->doors for the hot room, detecting any ice.

20190912185923_1.jpg

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Whether this is useful or not, will be determined. This can pretty much be arranged to freeze just about any solid liquid, and then remelt it afterwards.  Currently it fluctuates between 80kg/s and 1kg/s, based on where the liquid is at in the escher waterfall on the right side. 

melter-freezer.thumb.png.26ffb56066bf5be9d65b60cdf914b6f1.png

The liquid rapidly freezes, dropping on the waiting door. All three doors open, dropping the solid to the bottom door and then they close (top first, middle second, bottom last). The solid ice gets trapped in the door for rapid melting.

When the ice melts, water falls out the mesh tile at the bottom, almost at melting point (272.7K is pretty close) despite the door being >380K. I keep the temp sensor in the nifty @Lifegrow module at 390, and close the door if the temp drops below this. I keep the cooler region at around 250K, and the ice drops on the waiting door at around 269-270K. Considering ice forms at 271ish, I'm pretty happy with it. With a little more tinkering, I'm sure I could get the flow more steady. The cooling zone will require an aquatuner to keep things cool, so removing it really isn't an option. 

Essentially, this is a freezer-melter that can abuse massively any possible power we can suck out of a liquid-solid phase change.  Now we just need to find the best option for adding heat (we already got one that removes heat from the crying crab with ethanol's liquid-gas change).   

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16 minutes ago, 0xFADE said:

Does it melt and drop out with the door still closed?  I wouldn’t have expected that.  I guess it has nowhere to go but that mesh tile. 

Yep, it does exactly that. The process freezes, pretty dang close to the temp needed for freezing, and then melts, pretty dang close to melting.  Here is a rough estimate of what happens (which lead <-> molten lead does as well).

  1. Water starts at 272.5 K
  2. Water is cooled to 269.5 K (3K drop)  (heat is gained to outside system)
  3. Ice immediately forms at 271 K (then drops a bit from extra cooling)
  4. Ice increases to 272.5 (heat is removed from outside system, about 1/4th the heat gained in step 2 since SHC of ice is about half water)
  5. Water leaves at 272.5

Each time you cycle this, you essentially get a 2.25K increase in water heat (so for a full pipe that's (4.179 DTU/g/K)*(10kg/s)*(2.25K) = 94.0275 kDTU/s, or roughly 94kDTU/s).  At 94kDTU/s created, you would need 8 wheezeworts to offset this heat generation. That's pretty decent. 

The problem with this setup is that we have to keep the cooling region cool, which means we have to supply the ENTIRE 3K drop in temp. The only way I know how to achieve this at 250K is with an aquatuner.  

In steps lead, possibly the fix to this problem. :) These are all rough estimates, but let's look at some napkin math. 

  1. Molten lead starts at  600K (actually 600.65K)
  2. Molten lead is cooled to 597K (3K drop)  (heat is gained to outside system)
  3. Lead immediately forms at 598.5 K (then drops a bit from extra cooling)
  4. Lead increases to 600K (heat is removed from outside system, about 1/2th the heat gained in step 2 since SHC's are equal)
  5. Molten lead leaves at 600K. 

Suppose we have a space age pump to supply 10kg/s of molten lead. Then we have 0.128DTU/g/K * 10kg/s * 1.5K  =1.92kDTU/s.  Not much, but wait. With a viscosity of 100, we can sent 100kg/tick into a cooling region, so we can pump 500kg/s into a cooling plate.  This means we can net 96kDTU/s. 

  • We now use a steam turbine with some vents closed to keep the cooling region at the right temp (so the 3K drop generates useable power). The steam turbine extracts 192 DTU/s.  We only have to keep the heating plate warm, which will require us loosing 96kDTU/s (supplying this heat from anywhere - magma, metal refinery, aquatuners, whatever).  The point is that we now only have to deal with the smaller half of the phase change. 

Basically, if you can get something to have a temp above say 650K (maybe 700K - not too hard as petro can do this), then you can double, yes double, the heat energy. 

=> Don't send your metal refinery coolant to a steam turbine. Instead, send it to a heating plate that melts lead. Then use the molten lead to DOUBLE the power produced. 

We now have heat energy doubling...... I'll step out before tomatoes are thrown.....

 

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