Good afternoon Dear Asgardians, i would like to start building a circle of people interested in the topic of heat dissipation in vacuum. It consists of the two processes of heat transfer and then dissipation. For the moment, what I have in mind is (1) heat transfer from electronics and its dissipation (2) Heat transfer and dissipation during mining in vacuum. I already know that a large other areas have this issue. But these two areas seemed interesting to me. I would be very happy to read your comments. We can start as a team and then divide to sub-groups for better team work efficiency.

Hi Marjan. You start an interesting topic and I have few propositions how to make it even better.

First, give definition of the "heat".

As I know, heat is the one of the forms of energy and its dissipation in space can be mainly by radiation.

Second, try to explain how you see result of this work and why it is useful for Asgardia. What is the goal of this research?

Maybe you want know how much energy is need to be spent to maintain "working" temperature of the devices that functioning in open space.

Hi Artem, if we want to have a spaceship with humans on board or a moon station, then we need to generate electricity. All the electronic devices which will use it, will generate heat. Any failure in any control system because of too much heat generation is fatal for the crew. I can imagine two important processes: first we must find a better way to effectively remove the heat from the electronic devices and then we dissipate it. The most reasonable dissipation method is to change heat to radiation which would then be radiated into space.

The other fact was about mining. Reaching to natural celestial resources would be a necessity for our nation too. One part of my PhD project was sent for Rosetta mission. One important problem was: when the MUMPS sensor war supposed to dig a hole onto the asteroid, there was an IR camera which was supposed to study the temperature at different surface depths but digging itself was changing the temperature. So effective heat transfer was very important. I think both of these issues are very relevant for future of our new-born space nation.

About heat that is produced by electronics. I think the most easiest way to transfer heat from one part of the device\space shuttle etc. into open space can be done by at least two-step system. First, we can transfer heat from electronics using simple conduction using some liquid for example (that is the good idea for not very hot place, around few 100 degrees Celsius), then coming second step, in which we will transfer heat from liquid to a some sort of a radiator (here still works conduction) and then this radiators will dissipate energy into open space thru radiation.

In general we can start some useful work by building computer mathematical model of such process, I think all necessary parameters for such model can be found without any problems.

P.S. Can you tell a little bit more about your PhD project? It sound very interesting.

Dear Artem, please let me reply to your comment stepwise.

About heat that is produced by electronics. I think the easiest way to transfer heat from one part of the device\space shuttle etc. into open space can be done by at least two-step system. First, we can transfer heat from electronics using simple conduction using some liquid for example (that is the good idea for not very hot place, around few 100 degrees Celsius), then coming second step, in which we will transfer heat from liquid to a some sort of a radiator (here still works conduction) and then this radiators will dissipate energy into open space thru radiation.*

The process of transferring the heat to liquid can be improved by adding materials with superior heat conductance. The liquid will then radiate heat slowly to space (Stefan-Boltzmann law). However, if you have a satellite you can remove liquid and think of changing heat directly to radiation with much more dissipation power.

In general we can start some useful work by building computer mathematical model of such process, I think all necessary parameters for such model can be found without any problems.

Which scenario? We need to simplify the model and improve it little by little. Which software will we use?

*P.S. Can you tell a little bit more about your PhD project? It sound very interesting.

In principle I was pressing a probe against a solid surface in presence/absence of liquid bridges. It was a basic science problem and I found many multidisciplinary applications for it since I have applied physics background.The other application was gas phase lubrication in MEMS industry. I am currently a post doctoral researcher.

Hi Marjan. Let's continue our exciting discussion.

So why I chose liquid? Just because it has maximum area of the contact with elements that will be emit heat. Of course if we talk only about small satellite, we don't need such complex system and radiation of extra heat will be the best way. But if we imagine more complex structure, I think such system may be good solution.

Now about model that we can build. First, it's very sad that we don't have any opportunity to put pictures here, so I will try may best to explain main idea as is. We can start from 2 dimensional system like this:

space | external shell | |--other shells--| |--- space inside satellite, electronics etc. ---| |--other shells--| | external shell | space
| | |-- --| |---- ----| |-- --| | |

This is the most simple scheme. Now how we can model behavior of such system? That's easy, we need build system of ordinary differential equations by which we can will calculate heat flux (J in scheme).

<-(J0)- heat produced here, and spreaded in both directions -(J0)-> ----*| |-- -(J1)-> --| | -(J2)-> | -(J3)->

We can set initial parameters of such system according to known data about heat produced by electronics (so we will know how much energy is produced per unit of time), after, knowing conductivity of the materials of satellite shell we can calculate flux of heat through one part of the shell to another one. And finally how much energy can be dissipate into open space knowing parameters of the external satellite shell.

At this step we can use software like "scilab", for example. It's free and has many interesting features.

P.S. My explanation is "raw", but I think you will understand main concept.

Hi Artem, let us continue. So why I chose liquid? Just because it has maximum area of the contact with elements that will be emit heat. Of course if we talk only about small satellite, we don't need such complex system and radiation of extra heat will be the best way. But if we imagine more complex structure, I think such system may be good solution.

I thought on a spaceship with crews we need water or liquids as an additional protection layer. In my opinion, we can use highly functional solid surfaces to do the same job as liquids. You are though right. For small satellites we can ignore the liquid and we get immediately to the point.

Now about model that we can build. First, it's very sad that we don't have any opportunity to put pictures here, so I will try may best to explain main idea as is. We can start from 2 dimensional system like this: space | external shell | |--other shells--| |--- space inside satellite, electronics etc. ---| |--other shells--| | external shell | space | | |-- --| |---- ----| |-- --| | |

It is indeed sad that we cannot attach files. I would prefer a bottom to top image as electronic chips\their space package\distance to the interior satellite wall\next layer...\exterior layer and finally space. One can add two modifications in this system. One is aimed for better conductance very close to electronics and the other for better dissipation.

We can set initial parameters of such system according to known data about heat produced by electronics (so we will know how much energy is produced per unit of time), after, knowing conductivity of the materials of satellite shell we can calculate flux of heat through one part of the shell to another one. And finally how much energy can be dissipate into open space knowing parameters of the external satellite shell.

I agree. then we can insert modifications and make conclusions.

At this step we can use software like "scilab", for example. It's free and has many interesting features. P.S. My explanation is "raw", but I think you will understand main concept.

I had never heard of this software before. I will install it and try to discover it. I got the idea. It is my pleasure to discuss it with you. I wish you a wonderful year ahead in 2017.Any other comment?

Hi Marjan. I am also pleased to have a discussion with you. Let in new, 2017 year, your dreams come true.

I hope that we can continue our interesting discussion, and not just talk about problem, but cooperate and resolve it. I think that it will worthy a few articles in relevant scientific journals, especially if we organize small team and expand basic model on more complex cases.

Few words about software that we can use. In general, for the first step we can use any program that solves system of the ordinary differential equations (like XPP http://www.math.pitt.edu/~bard/xpp/xpp.html).

I'm not familiar with the radiation of waste heat into space, but I would like to see if the waste heat from the electronics could be used to heat the station. Doubt it would be enough, but it could offset the electricity requirement to heat the living quarters.

Hi dunlivin. Of Course, if we will talk about huge space station, radiation of heat into open space will be just waste of resources that can be used for various purposes. Here we start from small problem for satellite and, I hope, we will expand complexity of the system on whole space station. So if you wish work on this problem with us, that's will be very good.

I didn't work out the details, but we could attach a lot of small Stirling engines that use part of the heat to create energy, and feed it back into the system, or use it to charge capacitors that can be used by laser/maser arrays to redirect incoming asteroids.

Heating a station wouldn't be an issue - the real issue would be getting rid of the heat. Look at the size/number of radiator panels on ISS. Sitrling engines are an interesting solution, but although this will allow for some re-collection/transfer of unwanted energy into something we can use, I'm sure the low electrical output from these devices will be infinitesimal compared to energy requirements - suggesting the more serious energy production methods employed would render any stirling output obsolete and just pure waste combined with the heat they make in operation would render it impractical.

Graphene is a great conductor of heat - it'd not make sense to build the entire heating array from, but definitely certain parts - like the heatsink in the primary exchange.

Radiation into space is quite possibly a waste, but it's the most effective method currently available to avoid cooking occupants by the running of machines that would otherwise keep them alive. For a habitation setup you'd not want to run the coolant systems directly through habitation. You'd want another system interacting with that which can optionally travel through any habitation. Then you don't have to bake the occupants to keep equipment cool, and wouldn't need to rip up people's habitation to mess with primary coolant systems.

The lack of pictures in here is a good thing. It stops random idiots putting random pictures in here for trivial reasons, which I'm sure without would rapidly make this look like a spam haven. Until we actually have services that can sensibly integrate diverse functionality making it sensible to collaboratively work on projects, you can include reference to pictures via links. Somewhere like imgur should be able to hold the image and allow to return a link that interested parties would be able to click to gain access to the image. Something like: http://imgur.com/QqSHQwF Precise service shouldn't be much concern, but care and attention to privacy policies, data collection policies, and lacking requirement to execute dozens of scripts on your CPU when it reqiures 0 scripts to display a picture are possibly worthwhile.

Hi everyone, first of all happy new year 2017 to all of you! Second, thank you so much for your comments. Graphene phononic crystals are very good options to start with http://passthrough.fw-notify.net/download/789018/http://nanoheat.energy.hust.edu.cn/upload/attachement/2016-10-20/76d66e6e2e804f35bd7891382b36f8f0.pdf. In general phononic crystals have unique thermal properties.I recommend that we do a literature research for 2 weeks. I have heard MIT is producing some even better ones :), I mean phononic crystals with better heat conductivites by using holographic interference patterns.

The other interesting method is to use metamaterials to change heat to light ttp://spie.org/newsroom/5129-a-metamaterial-to-convert-heat-to-light. I am not in favor of heating up the spaceship with the heat generated by electronics. The power and energy production is not a problem. However, I am very much in favor of changing heat to produce light (or more precisely electromagnetic waves). Then there must be a way to re-use it.

Hi to all who interested in this topic.

Graphene is a very good idea, but how much it will cost and how easy can be produced? We can divide main idea on two, one - is the best possible way using results of modern scientific researches, second - what real system can be built (I don't think that we can easily find few kilograms of graphene).

So, as was mentioned earlier, we can build a model and check it with different parameters and calculate possible cost and amount of materials that may be needed.

Convert heat to light is better idea in compare to Stirling engines. Just for fun will be very interesting to calculate how many such engines must to be placed on a space station to produce amount of energy, for example, needed for one computer. And also how much space is needed for all that engines.

Marjan, you have created this theme so, maybe, you should also be a leader for this research? If we want achieve some results, we need strategy. What and when we should do, what results we expect. And of course, if we plan publish results of this research we can't use this forum for discussion all steps in this work.

Sorry, due to error I accidentally created two messages and this one I can't delete. So admins if you see this message - delete it.