New method of compressed air for electricity storage. (ie battery)... - Page 1
Forum section: electronics / general

author: BrianHG
author_rank: Super Contributor
timestamp: March 27, 2017, 12:11:34 am
content: This lady says she got the efficiency way up for storing surplus solar power by compressing air in tanks. Is there anything to this?

author: FrankenPC
author_rank: Unknown
timestamp: March 27, 2017, 12:25:10 am
content: I like the idea of hydraulics and gravity. Cut a large vertical cylinder of say granite. Free it from the base so it becomes a titanic piston. Then, as solar power is idling during the day, it powers hydraulic pumps at the base of the cylinder. This would be using a VERY small fluid line as the ration of work to weight would be incredible. Multiple farms can feed into the same piston this way. At night, the lines are all combined and released through turbines. It's just a simple counterweight but on a huge scale.

author: BrianHG
author_rank: Super Contributor
timestamp: March 27, 2017, 12:27:46 am
content: Quote from: evb149 on March 27, 2017, 12:23:51 amDid you not watch the video. It's the heating of the air during the compression that she illustrated how it was solved. Also, the heat they remove is re-introduced during power generation. She does have a graph of the power loss differences with a typical compressed air system and hers. Also, she compares the cost and size of storage to Lipo at the end of the talk.

author: BradC
author_rank: Super Contributor
timestamp: March 27, 2017, 12:48:25 am
content: Quote from: BrianHG on March 27, 2017, 12:27:46 amI did watch the video, and while the concept is sound I'm still unsure of the absolute efficiency of the process. I know it's a 12 minute talk and they necesarily gloss over real facts, but there's a lot of handwaving "well it kinda just works like this". I'd like to see some more real detail. I have no doubt that there are some significant efficiency gains to be made by restricting the total heat of compression. The issue is by using water they are still capping it at 100C *or* they are using so much water it will have a significant displacement effect in the cylinder. She's also talking of water flows upwards of 3KG/s and injecting *during* the compression process, so there's a not-insignificant power involved in making that much water move at significant pressure.All in all a neat idea, but I'd like to see some quantification of the losses involved across the entire process. Not to mention the safety issues surrounding huge air storage vessels at 200 Bar, given the quantity of them that would be required to be distributed around the countryside, and then the projected vessel lifetime in both material and fatigue terms. I dunno if you've ever seen the remains of a 200 Bar vessel that ruptured. I've seen a couple of small ones (think SCUBA tank size) and it wasn't pretty. The size of that vessel in the talk makes my skin crawl.Ever the sceptic....

author: edavid
author_rank: Super Contributor
timestamp: March 27, 2017, 01:13:13 am
content: Did you notice that the date on the video is 2015?Did you notice that the last news posted on the company website is from February 2016?http://www.lightsail.com/news/Or did you read this article that Dave previously posted?https://www.eevblog.com/forum/renewable-energy/lightsail-energy-storage-fail/

author: Someone
author_rank: Super Contributor
timestamp: March 27, 2017, 01:18:38 am
content: There is already a thread on this company with more recent information:https://www.eevblog.com/forum/renewable-energy/lightsail-energy-storage-fail/But the basic concept of trying to recover some of the thermal losses in compressed gas storage is sound, they forget to point out that losses in the thermal storage greatly effect their efficiency claims so it can look good for hour by hour arbitrage but poor for long term storage as an isolated system. Compressed air storage is very interesting when you integrate it with other thermal demands of a house or business, just like micro CHP it can scale well to very small systems especially in a household. A typical residential dwelling has consistent daily demand for heating (water) and cooling (refrigeration) before you consider the possible dumps of HVAC, and the kicker is that most fridge/freezers are already using a gas cycle so its a mature and well accepted technology. Tying it all together is the hard part but a "smart" fridge that has half (or even perhaps 1/4) the running cost by being aware of pricing is already a viable product that no-one has built for the residential market. Integrate that into a micro CHP or HVAC system and the potential energy efficiencies and savings for a home owner add up quickly.

author: BrianHG
author_rank: Super Contributor
timestamp: March 27, 2017, 02:22:11 am
content: OK, it's BS. I get it...

author: Galenbo
author_rank: Super Contributor
timestamp: March 27, 2017, 07:46:46 am
content: So the neo-renewables clan now invented compressed air.They nearly arrived in what we know as 2 centuries ago, congratulations.That's worth a big applause in their libtard performance.

author: coppice
author_rank: Super Contributor
timestamp: March 27, 2017, 07:56:29 am
content: Quote from: Galenbo on March 27, 2017, 07:46:46 amMaybe you should trying reading about what they were trying to do before commenting. They were trying something fairly original, to deal with the key problem of energy storage by gas compression. It hasn't worked out very well, but they didn't just replicate 200 year old work.

author: Galenbo
author_rank: Super Contributor
timestamp: March 27, 2017, 08:33:33 am
content: Quote from: coppice on March 27, 2017, 07:56:29 amSo what exactly do you see as their solution, for which of the ever-known problems ?

author: Kleinstein
author_rank: Super Contributor
timestamp: March 27, 2017, 05:51:10 pm
content: There idea is getting closer to isothermal compression and move the heat to water. The heat is stored in separate tanks and when using the compressed air to convert back to mechanical energy / electricity they add the hot water.In theory this can improve the efficiency - but there are practical problems:The water tanks add significant costs and the efficiency still will not be that high as one still needs an significant temperature rise to make the heat storage cost efficient. Also moving the water around also adds losses.So they might get a significant better efficiency, but going from 10% to maybe 50% does not really help, even though it is a factor 5 up in efficiency.There are already a few larger scale plants using a similar idea - though with a lower pressure (70 ATM) and using hot rock/concrete for thermal storage. These systems are still not significant cheaper than other storage and relatively low efficiency. For storage they consider / use underground caverns in salt formations - so relatively cheap if large scale.A more efficient kind of compressed air storage is used in combination with a peak power gas power plant: Just like in a gas turbine the air is compressed and cooled, but than stored if needed. When energy is needed the stored compressed air is compressed a little further, burnt with gas and used in a gas turbine power plant. This effectively stored some of the energy the power plant produces with little overall loss in efficiency. Still it only works in combination with the gas powered plant, giving something like 30% stored energy and 70% from burning gas.

author: BradC
author_rank: Super Contributor
timestamp: March 28, 2017, 01:20:33 am
content: It's interesting watching this stuff (where "this stuff" covers pretty much every "bright idea" used to obtain funding from suckers) develop.When I were a lad, I had many a "bright idea" to do with free energy, increasing efficiency or general thought bubbles. I would sit down with dad and lay out my plan to save the world/make a million dollars/become famous (pick one or more) and he'd quietly explain *which* particular law of Physics I was trying to break and therefore whilst creative was strictly a no-go. I'd go away and think about something else. As I got older, I developed the ability to short-cut that whole process and look critically at my idea, do a bit of reading on the relevant natural laws and discount it as not-viable. I'm sure pretty much everyone reading this developed the same abilities.So what makes these nutters different? Where does the innate self-belief un-tempered by a basic understanding of physics/thermodynamics come from?

author: boffin
author_rank: Unknown
timestamp: March 28, 2017, 03:56:00 am
content: Weren't TATA going to release a car with compressed air energy storage ?https://en.wikipedia.org/wiki/Compressed_air_car#Tata_Motorshttp://www.greencarreports.com/news/1096772_tata-airpod-compressed-air-car-to-launch-in-hawaii-this-year-report