
Emissions-free energy system saves heat from the summer sun for winter - signa11
https://www.chalmers.se/en/departments/chem/news/Pages/Emissions-free-energy-system-saves-heat-from-the-summer-sun-for-winter-.aspx
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symplee
These liquid Norbornadiene Photoswitches have an energy storage density of up
to .559 MJ/kg.[1]

For comparison: Mechanical Flywheel- 0.36–0.5 Lithium-ion battery- 0.36–0.875
etc...[2]

[1]
[https://www.nature.com/articles/s41467-018-04230-8](https://www.nature.com/articles/s41467-018-04230-8)
[2]
[https://en.wikipedia.org/wiki/Energy_density#Energy_densitie...](https://en.wikipedia.org/wiki/Energy_density#Energy_densities_of_common_energy_storage_materials)

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sjburt
If so, storing a season's worth of heat might not be so feasible. A home in
northern Europe needs about 30,000 MJ, so that would be 53,000 kg of
norbornadeine.

If the system absorbs energy during the day and releases energy at night, it
might work with quite a bit less (maybe only a few hundred kg). It's
interesting that the article doesn't suggest that. I wonder if there is a
reason that wouldn't work--not enough solar energy in the winter, perhaps?

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m_eiman
_A home in northern Europe needs about 30,000 MJ_

Really? We live in central Sweden, just outside Gothenburg. According to the
estimate from our power company, our house uses about 15,000 MJ per year - and
we have a single floor 200 square meter house. It's rated "C" in energy
efficiency (which is the minimum rate allowed for new housing now).

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bjelkeman-again
I live in a house from 1909, with a heat pump (bergvärme). We probably use
18000 kWh for hearing in a year, 64800 MJ, at 190 m2 plus basement. 30000 MJ
wouldn’t be enough for us I guess.

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jpollock
My first thought was about Drake Landing in Alberta. They use heat pumps and
store excess summer heat in the ground for use during the winter[1].

Nifty that this is a new molecule for long-term rather than seasonal storage.

[1] [https://www.dlsc.ca/](https://www.dlsc.ca/)

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anon1253
Does anyone know of similar technology for the inverse? Saving cold from the
winter for the summer? With hotter summers and more extreme temperature swings
to be expected, it might cut costs on running the AC's

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jmkd
For thousands of years ice and snow have been gathered in winter and stored
for various summer usages in purpose-built structures, ideally underground:
[https://en.wikipedia.org/wiki/Ice_house_(building)](https://en.wikipedia.org/wiki/Ice_house_\(building\))

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skookumchuck
You can do the same thing today simply by burying tubes in the ground, at
least 6 feet down. The ground is cooler in the summer than the air, and warmer
in the winter. This can pre-heat and pre-cool air for your HVAC system.

It's been around a long time, I'm surprised almost nobody uses it.

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stjohnswarts
I can't personally because 8 inches down is solid rock. To remove all that
rock would cost a fortune to get down to 6feet.

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doikor
For a ground heat pump system you don’t need to remove the rock. You just
drill a hole into it. My parents did this and their house is built on top of
solid rock.

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mchannon
[https://en.m.wikipedia.org/wiki/Norbornadiene](https://en.m.wikipedia.org/wiki/Norbornadiene)

Wikipedia has a pretty thorough chemical description. Fascinating, really.

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pfdietz
A long term storage system has to have very low capital cost, as it doesn't
have many cycles over which to amortize that cost. I doubt this system makes
any economic sense.

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ianai
Trying to figure out marginal cost. I think some part of it uses coal tar as a
precursor. It might actually be pretty cheap and/or the US may have a
comparative advantage given how much coal it has.

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foxhop
I'm the process of building a "breadbox" \+ coldframe hybrid to warm hot water
using the sun.

Similar design:

[https://youtu.be/tqUwBwfN5iE](https://youtu.be/tqUwBwfN5iE)

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finnh
> He hopes that the research group will shortly achieve a temperature increase
> of at least 110°Celsius ..

So, enough to boil water? Once you can execute a phase change you can generate
electricity, not just heat....

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mrfusion
Can this also store heat from electricity?

If so I’m wondering if this couldnrevolutionitize the lowly water heater.

I believe they use a lot of energy just keeping their tanks at the right temp.

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gus_massa
It's weird that the article has no data about the molecule. You can find it in
the research articles "linked" at the bottom.

