6 ms·
I saw a talk from MIT professor who came up with a similar idea[0]. Using spheres seemed like a pretty good idea on paper, but when they started doing the cost
by gene-h 10y ago
I saw a talk from MIT professor who came up with a similar idea[0]. Using spheres seemed like a pretty good idea on paper, but when they started doing the cost analysis they found that it would be cheaper to use cylindrical pipe.
Even though one uses more concrete, it's cheaper because we already have the infrastructure in place to produce and lay long concrete pipes.
In both cases he also recommended using such energy storage systems as anchors to hold offshore wind turbines in place, because the concrete is more than heavy enough to do so.
[0]https://www.naefrontiers.org/File.aspx?id=48498 https://www.naefrontiers.org/File.aspx?id=48498
- tzs 10y agoWould a cylinder be strong enough? The Germans are talking about operating at a depth of 700m, which is more than twice the maximum depth (300m) of the example analyzed in the paper you cited.
- chillydawg 10y agoUnder sea pipelines for a variety of depths, pressures and capacities are a solved problem, courtesy of the oil and gas industry.
- heisenbit 10y agoThese pipelines have some inner pressure. The idea is here however that a pressure differential is used to drive a turbine. The greater the differential the more energy. The engineering challenges are not really comparable. The engineering challenge is more comparable to submarine design. Nuclear submarines go down 500m and even the navy deep submergence rescue vehicle http://www.navy.mil/navydata/fact_display.asp?cid=4100&tid=500&ct=4 http://www.navy.mil/navydata/fact_display.asp?cid=4100&tid=5... is going 1.5km deep only with its tube design. Compare this with really, really deep dive designs like https://en.wikipedia.org/wiki/File:Trieste_nh96807.svg https://en.wikipedia.org/wiki/File:Trieste_nh96807.svg with a sphere observation gondola.
- Mchl 10y agoSeems to me that if you use compressed air to displace water within the sphere, you could actually store more energy this way... That would require the air to drive electric generators when the sphere is being filled with water though.
- skosch 10y agoOnce you start compressing and decompressing air you get a lot of heat loss though, that I would imagine isn't as much of an issue when you're just pumping plain water back and forth
- vibrolax 10y agoThe US Navy's DSRV's you referenced do not have cylindrical pressure vessels. The cylindrical external hull encloses 3 linked spheres that are the actual pressure vessel. BTW, the DSRV's were retired several years ago.
- deleted 10y ago[deleted]
- gene-h 10y agoThe paper cites a depth of 700 meters too for either system. Compression happens to be concrete's best operating mode.
- dugditches 10y agoIf these are intended for the sea, the reinforcing bar would likely have to specialty(stainless). Lot easier to create a skeleton in the shape of a cylinder(cassion[1]) as you said, versus a sphere. [1] http://www.thebluebook.com/inc/img/qp/75476/rebar-cages-for-drilled-piers.jpg http://www.thebluebook.com/inc/img/qp/75476/rebar-cages-for-...
- bathyspheric 10y agoI don't think the bar would need to be stainless. The reinforcement cage in concrete weight coating used on subsea pipelines is relatively ordinary steel. The steel is protected from corrosion by the concrete itself and a system of sacrificial anodes that are easy to survey and replace. (I help design pipelines)
- liotier 10y ago> The steel is protected from corrosion by the concrete itself I guess that the steel is protected by something else because, as the pre-1970 builders ignored and as it dawned on everyone else 20 years ago, concrete is not waterproof.
- dugditches 10y agowas what he was referencing. https://en.wikipedia.org/wiki/Galvanic_anode https://en.wikipedia.org/wiki/Galvanic_anode
- Arizhel 10y ago>concrete is not waterproof. Ancient Roman concrete is.
- Freestyler_3 10y agoSpheres would not use as much square meters right? Long pipe would need more space, protected space.
- gene-h 10y agoYou are referring to the threat of trawling nets yes? So the idea presented in the paper is to use these things as anchors for wind turbines, it would not be a very good idea to go trawling through an offshore wind farm. Of course in either case, it is more likely that such structures will damage the trawling net rather than being damaged by the trawling net.
- astrodust 10y agoThey're testing a concept here that's basically under-water balloons to store potential energy: http://hydrostor.ca http://hydrostor.ca It's a pretty small-scale experiment, but everything has to start somewhere. The Deep Lake Cooling Project was prototyped at some point and that's well into production now, providing inexpensive cold water for chillers through the downtown core: http://www.canadianconsultingengineer.com/features/toronto-waterfront-toronto-cools-off-naturally-a-deep-lake-water-cooling-system/ http://www.canadianconsultingengineer.com/features/toronto-w... The Hydrostor project is roughly located in the same area as the Deep Lake intake pipe comes ashore.