LATENT COOLING (ENERGY) STORAGE VERSUS CHILLER POWER INSTALLED 1

[foxstar]

I'm coming back again to these fantastic foruns and may I propuse a quite wide and interesting matter, I believe: "LATENT COOLING (ENERGY) STORAGE VERSUS CHILLER POWER INSTALLED".
It is known that combining a chiller installation with a ice-rink ou a with whatelse cooling storage, (it should be a must in design!) we can save up 50 to 80 % on the size of the installed chiller power (and therefore associated electrical facilities, as well). Does anyone have experiences, case-studies, references about the state-of-art and the installations working properly. Because those I know, don't work efficiently, and that´s really a pity! Thank you all for any contribution.

 

[KiwiMace]

Ice and chilled water storage is a maturing technology and thus substantially documented and case studied through a number of industry organisations. What are you looking for here?

 

[IRstuff]

You're suggesting replacing 50% of a chiller with an ICE RINK? Where's the savings here?

TTFN

FAQ731-376
Chinese prisoner wins Nobel Peace Prize

 

[foxstar]

To IRstuff, The electrical tariff during the nigth in that site is 1/3 cost of that one during the working day. The cost difference pays you the ice-rink in 7 to 10 years of running-time. It's mentioned that the replacing power chiller can go up to 80%, therefore to have a chiller unit to help to response mainly in the peak-solicitations, which happens in the middle of the afternoon, (Office, comercial buildings). Of course, it should be always a common balance between the period of time you have in the night and the cooling energy you need during the day.

 

[btrueblood]

Given that you've stored the energy in the ice, you must recover that energy during the day by melting some or part of the ice...but who wants to skate on slush? Irstuff's comment is pertaining to this; normally the ice in such systems is stored in an insulated vessel, not in an ice rink.

 

[KiwiMace]

I think the OP is mixing up ice storage with colocating heat sinks and sources. The most cited example is to put a swimming pool next door to an ice rink. You harvest heat from the rink and recover it in the poolwater heating. As pointed out above, a functioning ice rink makes for pretty poor ice storage.

 

[dcasto]

First relook at your time of use contract. Our local contract has 8 cent power at night and 15 cent day OR 11 cent anytime. Storing energy, either as ice or molten salt has almost no payout.

 

[IRstuff]

foxstar,

You seem to assume that there are no associated costs for maintaining the storage facility, but nothing comes for free. The machinery for maintaining the temperature, for switching between the two modes of operation, the cost of the real estate itself, etc.

When the associated costs are included in the economic calculation, one may find that the payback is absurdly long or even nonexistent.

TTFN

FAQ731-376
Chinese prisoner wins Nobel Peace Prize

 

[foxstar]

To dcastro: One date-input is that I pay during the day, I mean in three times more for 1 kWh-day than for 1kWh-night. Don't you think that could be an oportunity to explore the save-cost potencial difference? Have you real data which says that I'm wrong. In my experience and taking in account with the associated costs for maintaining the storage facility, as IRstuff, well has mentioned, I getting paybacks between 7 and 11 years. I have to assure, confirm these results. I have been heared that, "forget it, it's not wortth" but Nature do so, so well in some cases why not we the engineers??

 

[KiwiMace]

If the 3-1 day to night tariff split doesn't get you close enough for the money men, you can consider using your coolth for peak load shedding and save a chiller on new builds.

There are lots of other good reasons for ice or chw storage that don't need a 3-5 year payback to justify. Unreliable power supply and critical loads being the top bills.

 

[mauricestoker]

Diurnal storage has been around for some time. The Dr. Strangelove atomic-bomb resistant presidential command center designed in the 40's and constructed in the 50's at building 54, Walter Reed, included a diurnal storage system with two 600-TR chillers. It was a brine system.

There are quite a few diurnal storage systems in operation that have documented positive LCCA's; modular systems are available as well. It's not a one-size-fits-all approach; the LCCA should be done first. Local utilities demand side management programs might be available to offset part of the cost; the peak grid load would proably be coincident with the peak heating demand, depending on where you are at, and could pay you for peak load shedding.

 

[foxstar]

To mauricestoker: Sorry my ignorance, what you mean by LCCA ? (probably a not so long payback ?). Please can you bring to this discussion real cases, experiences you dealt with? Thank you!

 

[mauricestoker]

My experience was with a life cycle cost analysis that did not favor diurnal storage. Even with rate schedule and weather conditions being favorable, the existing massive construction (reinforced 22" thick, atomic bomb resistant) created so much thermal storage that we had about a 12 hour thermal lag. The building itself stored as much cooling as the brine tank. The building had redundant 12.47 kV feeders with generator back-up, so reliability was not an issue.

BAC, the largest cooling tower manufacturer in my area, has packaged units for ice storage. Address is

http://www.baltimoreaircoil.com/english/products/ice-thermal-storage/process-cooling/designselection

Calmac might be another useful source for where the LCCA was positive.