[HN Gopher] Sea water district cooling feasibility analysis for ...
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Sea water district cooling feasibility analysis for Hawaii [pdf]
(2002)
Author : geothermal_all
Score : 56 points
Date : 2020-12-25 18:11 UTC (4 hours ago)
(HTM) web link (energy.hawaii.gov)
(TXT) w3m dump (energy.hawaii.gov)
| [deleted]
| hourislate wrote:
| I've read about this before when Toronto was implementing a
| system like this. The City of Toronto cools a large portion of
| it's downtown office towers using this method. They draw cold
| water from deep in Lake Ontario to be pumped into chillers to
| cool the office buildings. Seems to be environmentally friendly
| and cost efficient.
|
| A couple of links:
|
| https://www.acciona.ca/projects/construction/port-and-hydrau...
|
| https://www.toronto.ca/community-people/get-involved/public-...
| Scoundreller wrote:
| Sorta. They run heat exchangers between the in-bound municipal
| water and loops that go to the office buildings.
|
| So it helps with some eco-effects (ie: there's no dumping of
| the heated water), but everyone's municipal water is a bit
| warmer in summer. I don't think the effects of that have been
| calculated. Can offset water heating a bit; but other office
| towers use that water for their a/c cooling needs.
|
| They deepened the water intake too, so it definitely means
| colder tap water in winter too, which residents mostly have to
| heat up inefficiently.
| dzhiurgis wrote:
| Is there a limit how hot or cold your waste water can be?
|
| In many eastern europe cities heating is centralised and uses
| quite expensive wood or oil burners. Wondering if extremely
| deep geothermal bores could serve 200-500k people.
| 404mm wrote:
| It's kinda hilarious (to people living in areas with actual
| seasons) to hear about summer and winter in Hawaii. Based on
| the temp averages I see on weather.com, there is some
| variation. But how does it actually feel? Does "Hawaii
| winter" feel like actual different season or is it just
| "slightly less hot summer"/every other day?
| fghorow wrote:
| Cornell University has a similar cooling system using cold water
| from Cayuga Lake.
|
| https://fcs.cornell.edu/departments/energy-sustainability/ut...
| codetrotter wrote:
| Millions of kWh. Aka, many GWh. Why call it the former instead of
| the latter?
| boulos wrote:
| That's what the submitter chose as a submission title. The
| document's title is "Sea Water District Cooling Feasibility
| Analysis for the State of Hawaii".
| BooneJS wrote:
| I assume it makes it relatable to people who are accustomed to
| seeing kWh on their electric bills.
| lostlogin wrote:
| Bills for thousands of cents.
| schoen wrote:
| If you want to normalize the SI units, you could also replace
| "many GWh" with "many TJ".
| Tyr42 wrote:
| I also think we should say the moon is 384 Mm instead of
| 384,000 km. Mega meters are awesome, we should use them more.
| And the earth sun distance is 150 Gigameters.
| toomuchtodo wrote:
| (October 2002)
|
| Any more recent developments on this front?
| snissn wrote:
| Since then there's been a lot of wind farms installed in Hawaii
| and most homes have solar powered water heaters (from personal
| observation). Don't know anything about the sea cooling concept
| but it seems viable and for long time cornell has done it or at
| least on a tour they said they did
| https://fcs.cornell.edu/departments/energy-sustainability/ut...
|
| https://www.ithacajournal.com/story/news/local/2015/10/02/co...
|
| Interesting..
| m-ee wrote:
| Talking to locals in Maui most aren't very happy with the
| wind farms. They're considered an eye sore and they were sold
| under the pretense of lower electricity bills which never
| happened.
| snissn wrote:
| Ah here is the older one I remember from a tour
| https://fcs.cornell.edu/departments/energy-
| sustainability/ut...
| [deleted]
| boulos wrote:
| Looks like a deal was "reached" in 2018 [1], but just this week
| "Honolulu Seawater Air Conditioning to end development after 15
| years" [2] and their website is now a scam. The Wayback Machine
| has the original [3].
|
| [1]
| https://www.bizjournals.com/pacific/news/2018/10/09/hawaii-f...
|
| [2]
| https://www.bizjournals.com/pacific/news/2020/12/19/honolulu...
|
| [3]
| http://web.archive.org/web/20200929031903/http://honoluluswa...
| supernova87a wrote:
| I just don't understand why Hawaii government has been so slow to
| mandate the most economically-net-positive renewables, given
| their astronomical electricity costs (old, shipped-in fuel,
| diesel-fired generators).
|
| Solar hot water, solar PV, wind. Stop being held over a barrel
| with these electricity costs. They live in the most conducive
| place for it in the world, yet don't take advantage of it,
| really.
| aphextron wrote:
| > I just don't understand why Hawaii government has been so
| slow
|
| Island time is a real thing. And politics in Hawaii takes
| nepotism and "good old boys" networks to the next level. Things
| are the way they are because the people in charge are happy
| with it.
| metanoia wrote:
| HART (the light rail system they're building) is a complete
| disaster, for the same reasons.
|
| I can't see the government there being able to handle much of
| any major infrastructure project. The airport expansion is
| moving at a glacial pace as well. And it's a miracle the H3
| ever got built.
| toomuchtodo wrote:
| Minor quibble: It's more efficient to use a heat pump water
| heater, and max out your PV solar instead of splitting PV solar
| with solar water heating.
| abdullahkhalids wrote:
| Is it? Solar PV overall efficiency is probably 15-20% of the
| incoming solar power. While, a solar thermal hot water system
| can reach 50% or higher efficiency, even accounting for
| storing the hot water for several hours.
|
| Solar thermal also just requires fairly cheap mirror like
| surfaces, while solar PV requires semiconductor chips.
| pedrocr wrote:
| Heat pumps are at the 400% efficiency level so by your
| numbers they're already ahead. And PV has other advantages.
| It's easier to install since it doesn't require specific
| tubing and the panels are much lighter. The energy is
| useful for other things when you don't need as much hot
| water. And efficiency goes up in winter because PV is more
| efficient in the cold whereas efficiency of thermal solar
| goes down as you need to heat the panel before heating the
| water. It will depend on your local PV and heat pump costs
| but thermal solar seems less and less relevant these days.
| coredog64 wrote:
| AIUI, ground source heat pumps get really expensive when
| the ground is really hard. A reasonable proxy is "do your
| neighbors have basements?" If the answer is "no", then
| it's probably because digging is more trouble than it's
| worth.
| pedrocr wrote:
| Efficiency is still good for air source heat pumps IIRC.
| They only go down to 100% at well below freezing which is
| probably not a problem in Hawaii. Ground source only
| requires a small hole though, of the kind that is done
| for water. I'm in a granite rich area where basements are
| very rare but water wells are very common and reasonable
| cost to drill.
| supernova87a wrote:
| Oh, well I mean for simple cheap residential don't-have-a-
| lot-of-money-to-spend, a do it yourself hot water solar
| system is just about the cheapest, easiest thing you can do,
| right?
| rurabe wrote:
| As is usually the case, it's complicated.
|
| The government has actually taken steps to push us down that
| road by mandating that all generation is renewable by 2045. Of
| course that's easy to say and harder to do, but I'm not sure it
| should be up to the government on how we get there.
|
| The entity with the most responsibility to get there is HECO,
| which has a bit of a mixed record.
|
| On one hand they have been pretty good about encouraging
| customer generation with net metering, and later grid supply
| options. Unfortunately there is a bit of an engineering problem
| there as we have pretty much reached the saturation of customer
| solar such that in the middle of cold sunny days, there is more
| electricity being produced than consumed (see duck/nessie
| curve). This would sound like a good thing, but with an
| extremely old grid and no utility level storage, it's kind of
| not.
|
| A more reactive utility perhaps would have done a better job
| upgrading the grid to allow for distributed generation, but
| HECO spent the better part of the last 5 years trying to get
| themselves sold to a mainland utility to drive returns to
| shareholders instead of placing institutional focus on solving
| current or future problems for ratepayers. Serving two masters,
| etc.
|
| Kauai has a much more interesting situation as their utility
| went through that whole sale to the mainland thing in the 90's,
| which failed and provided the opportunity for the ratepayers to
| buy the owners out and created a cooperative utility. I don't
| live there but from the outside looking in it looks like they
| are being much more proactive about renewables and more
| importantly, storage.
|
| Absent some kind of massive game changer in wave or wind
| generation, the whole game is really storage. I know a lot of
| people who would love to install solar, but HECO is already at
| max capacity absent a way to store electricity at scale.
|
| Finally the part that gets talked about the least is economic
| inequality. Hawaii's real estate is expensive, but it is driven
| by investment from outside the state, making it almost
| impossible for people who live here to afford homes. That
| interacts with the energy piece because you have to be a
| homeowner to benefit from solar, so solar contributes to wealth
| inequality as people who are fortunate enough to own homes also
| reap the benefits of government subsidies and cheap
| electricity, while people too poor to own homes are left paying
| the retail rates. And this is before we even get into the
| distortions of behavior that net metering encourages when you
| treat a kwh of solar in the day as equal to a kwh of petroleum
| at night.
| nradov wrote:
| No need for mandates. Power and fuel are expensive so people
| already have a strong incentive to invest in renewable power
| and efficiency improvements.
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