So as opposed to just talking about a problem per the “Cooling With CO2” thread, here’s a thread to discuss and design a solution!
I’m no fabrication engineer, I know some of you are though.
I know we would need a pump to actively compress the gas into recovery tanks. Some valve assembly to switch tanks and whatnot.
I don’t want to say people should or shouldn’t do anything, but, there’s gotta be a “best” version of it that isn’t completely unbridled as far as environmental impact. This concept is just as important as the closed loop system, in fact, it is one!
My philosophy with creating manufacturing items. Prototyping? That can be made, but be ready for the fail rate to be 3+ prototypes until a functioning solution.
Your shitty scratch paper drawing can be turned into a blueprint for an autocad followed up by prototyped and patented product. If the proof of concept isn’t made yet, I’d figure out your initial drawing for prototype #1
I doubt I’ll be able to raise any capital until possible regulations are looming. I suppose taking as many steps as possible until then is a good option.
Breh if I could get the Canna Clamp crowd sourced on pre-orders and profiting with world wide distribution of a hair straightener that made dabs. I can make your fancier shenanigans a reality for labs.
Just a thought, maybe you could make dry ice out of the exhausted LCO2 also, maybe not useful in your scenario, maybe it is, seems easier, but I am not sure how dry ice is made.
Forgive me if I missed something, but the idea is that people are blasting LCO2, using the DX to cool a load, and you’re talking about some sort of system to recompress the CO2 and condense it? Isn’t this just a refrigeration system using CO2 as a refrigerant (r744)? Its a great refrigerant, don’t get me wrong, I just feel like you might want to relable the project as “open source r744 cryo chiller”.
It just begins a refrigeration loop and at that point is put up against other refrigerants and their efficiencies. I think us closed loop operators don’t like waste and see LCO2 drain to waste systems and have the thought to recapture it.
Could be worth it. An HVAC engineer should be able to figure out what heat transfer needs to take place after compression to get it back to the parameters it is right out of the bottle in the first place.
An actual industry solution available is an “iced tech” from bhogart but it heat transfers a fluid to a column instead of running the cycle through a jacketed column for good reason. It’s expensive, gets cold, but doesn’t handle a load more then 2 jacketed columns. Even at that thought it’s a giant recirculating chiller.
If I had the resources I’d wrangle up a test it doesn’t sound hard to make a prototype. Sounds fun in fact with no expectations involved.
I should also point out that CO2 is an excellent low temp refrigerant because of its high vapor density. We build cascade systems using Copeland ZO compressors for the low stage and they work awesome. But the vapor pressure is too high to practically use for a single stage system that heat exchangers to atmosphere.
Another route is to let the co2 off gas and use a bio-filter to decompose. . Also this route can take ethanol degassing away. Mother nature knows how to heal herself. My biz partner started talking to me about this earlier because were looking at commercial greenhouses with hybrid systems that use concrete due to tropical location. The co2 emissions are off the chart. I’m trying to find the correct method but its pumping air contaminants into soil and letting microorganisms decompose the co2 into the soil. The energy from this could be looped back to the energy company to sell while having composted dirt. Also i know future has been looking at bio-pulping. This all could be be a big loop. Here is an article on bio-filtration http://www.bioline.org.br/pdf?st05010
Here is the article he sent me with the process and pulping.
A metering device i belive is what is used. Went to hvac school and did a year of work but honestly dont remember much so take that with a grain of salt.
I think the primary difference is this won’t technically be a single unit, which I believe would describe a chiller. It’s a design that people can alter to fit their particular system and needs.
So, for example, let’s say a company had 4 separate extraction units that they want to use CO2 to chill, one could position them in such a way that having the lines plumbed correctly would allow them to simply attach a line from a source tank. Whether it’s a giant tank or 70lb tank, and chill a single unit, or all 4 units, and have manifolds leading to the pump and compressor constantly recovering into tanks to be rolled over and used again, or fed back into the giant source tank.
This could function almost exactly like an extraction machine that uses CO2 to extract, but, with significantly lower operating temperatures and pressures. All the while, having the scale of it only be restricted by number of pump/condenser recovery units, or the size of the pump/condenser.
The condenser for this idea is relatively simple, a jacketed cylinder containing lots of tiny tubes for the CO2 to pass through and condense to liquid state. The pump does most of the work via compression so the jacket doesn’t have to be super cold.
So, I still think the system is going to be comparable in complexity and cost to an actual chiller with a refrigerant distributor/load switching station, but with a bunch of downsides. The biggest problem I see is choosing an appropriate pump: any HVAC compressor (scroll/hermetic) is going to be out because you will pump all of the oil out of it. That leaves you a selection of waaaayyy more expensive slower pumps (piston recovery pumps or diaphragm pumps). In order to get adequate cooling, you need a lot of pressure drop so the evaporator side will have to stay at a very low pressure; that means either a very big vessel (not practical for CO2 for a whole shitload of reasons) or a quick pump.
Shell and tube is an expensive option for a condenser, but there also aren’t a lot of plate exchangers that can handle CO2 pressure. Honestly, an HVAC condenser rated for r410 is your best hacky option.
I can drop some components and such for an “open source” cascade chiller using 410 and 744 but it’s not very “DIY” because to work with CO2 pressures you need to braze a ton of stainless to copper joints which is absolute hell.
