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#76 2023-01-23 18:59:59

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,844

Re: Thermal Energy Storage

Post #75 was assembled using Google.

I asked Bing the same question and ** this ** time I got a nice collection of downside snippets....

Rather than post them I decided to just report a couple of them...

1) The hypocaust system was inefficient
2) The hypocaust system was dangerous because of Carbon Monoxide

The Romans who could afford central heating would not have been concerned about efficiency.

The Romans knew about the danger of lead (or at least ** some ** did) but apparently Carbon monoxide was an unknown part of the environment.  The closest I could find was a preference for plenty of fresh air in habitations.

In a modern highly engineered heating system, efficiency is high, and dangers of CO getting loose are minimized.

The most common modern system of floor heating (as shown on This Old House, etc) is hot water pipes embedded in concrete floors.

Electric heating is another safe possibility today.

(th)

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#77 2023-01-23 20:12:07

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 29,178

Re: Thermal Energy Storage

Yes a reliable but labor intensive fuel supply even with pellet you still get a workout moving the bags.

Current temp is 45F inside with it near freezing outside.

Update
Tuesday morning temp is 43 F inside after being without any power for refrigerator to evaporate heat into the house, or fro stove or microwave use.

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#78 2023-01-23 20:37:38

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,844

Re: Thermal Energy Storage

For SpaceNut re this topic and planning ahead for power outage....

If you had a sand heat store in the basement, you could heat it up with electricity ahead of a storm.

This is a very simple concept, but it could help to keep the house warmer than it would be otherwise, when the power goes out.

(th)

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#79 2023-01-24 07:29:11

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,844

Re: Thermal Energy Storage

This is a follow up to Post #78

Google came up with a set of snippets that appear to show promise for thermal energy storage in sand, with application to homes as well as larger buildings.

Thermal energy (apparently) can be stored in a home before a power outage, and then recovered as needed.  It would appear that a small amount of power is needed to force cold air through the hot storage volume.  A worst case scenario would be to use a bicycle/exercise machine to drive a fan.

What is a sand battery? — Polar Night Energy
polarnightenergy.fi › sand-battery
A “sand battery” is a high temperature thermal energy storage that uses sand or sand-like materials as its storage medium. It stores energy in sand as heat.

People also ask
Is sand good for heat storage?
How long can sand store heat?
What is the best material for storing heat?
How do you store energy with sand?
Technology - Polar Night Energy
polarnightenergy.fi › technology

Store Wind and Solar Power as Heat in Sand. Our novel solution enables the up-scaling of solar or wind energy to up to 100% of your heating and electricity ...
What is a sand battery? · Solutions · News

First Commercial Sand-based Thermal Energy Storage Is in Operation
www.renewableenergymagazine.com › storage › first-commercial-sandbase...
Jul 7, 2022 · Polar Night Energy's first commercial sand-based high temperature heat storage is now in operation at Vatajankoski power plant area.

Commercial debut for sand-based thermal-energy storage
www.chemengonline.com › thermal-energy-storage
Aug 1, 2022 · The sand can be heated to temperatures of 500–600°C, and stored for long periods of time. The storage is unloaded by blowing cold air through ...
This big, sand-filled energy storage silo can be powered by wind ...

electrek.co › 2022/07/08 › sand-energy-storage-wind-solar
Jul 8, 2022 · Sand-filled energy storage in Finland. Polar Night Energy's heat storage system is a 23-foot-tall steel container filled with 100 tons of sand.
Using Hot Sand To Store Energy - CleanTechnica

cleantechnica.com › 2021/08/31 › using-hot-sand-to-store-energy
Aug 31, 2021 · ENDURING uses electricity from surplus solar or wind to heat a thermal storage material — silica sand. Particles are fed through an array of ...
Can Heat Be Stored in a Sand Bed Beneath the House?

www.greenbuildingadvisor.com › article › can-heat-be-stored-in-a-sand-be...
Aug 4, 2010 · Seasonal heat storage in sand? A sand bed has a relatively low heat capacity, relatively low conductivity, little stratification tendency, and ...
World's first 'sand battery' can store heat at 500C for months at ... - ABC

www.abc.net.au › news › science › sand-battery-debuts-in-finland-world-fi...
Jul 18, 2022 · The sand is able to store heat at around 500–600 degrees Celsius for months, so solar power generated in the summer can be used to heat homes in ...
Sand for Thermal Energy Storage - YouTube
www.youtube.com › watch

May 23, 2021 · Discussing the idea of sand for thermal energy storage of heat for months intended for ...
Duration: 11:18
Posted: May 23, 2021
Seasonal Thermal Energy Storage Gets Hot With a 'Sand Battery'

www.treehugger.com › News › Treehugger Voices
Jul 11, 2022 · At Drakes Landing in Alberta, Canada, solar thermal collectors gather heat and dump it into an insulated sand and rock storage area underneath ...
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Thermal Storage Systems - How Energy Storage Could Harm.
Not all energy storage is clean. Some could increase greenhouse gas emissions. Read More. All-green energy storage could increase greenhouse gas emissions if not done carefully.

Sand heat exchanger
DIY sand heat storage
Sand heat battery
Sand heater
Thermal energy storage
Sand battery for home
Sand battery capacity
Heating sand

(th)

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#80 2023-01-24 07:52:01

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,844

Re: Thermal Energy Storage

This is a follow up to Post #79

It would appear that thermal energy storage may be a practical option for some members of the forum.

It would be good to see practical energy storage solutions in use by members of the forum, when they make sense.

If anyone decides to embark upon an initiative to investigate this concept, please report your discoveries/observations here as you have time.

Thinking out loud ... a stack of bricks might work as well or better than a volume of sand, because electric heating coils could be threaded through the bricks to provide energy input, and air could be flowed through the bricks when heating is needed. 

(th)

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#81 2023-01-24 07:55:08

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,844

Re: Thermal Energy Storage

As a follow up to Post #80, Google found snippets about thermal energy storage in bricks:

View all
People also ask

What material is best for storing thermal energy?
How do you store energy in bricks?
How do you store thermal energy at home?
Can red bricks store electricity?
How 3000 Degree Bricks Will End Battery Storage - YouTube

www.youtube.com › watch

Oct 4, 2022 · Rondo Energy have recently received millions of dollars in investments for their thermal ...
Duration: 8:01
Posted: Oct 4, 2022

"Melting choc chip" blocks could stack up as grid-scale energy storage
newatlas.com › energy › mga-thermal-blocks-grid-scale-energy-storage

Sep 8, 2020 · A surprisingly simple new energy storage system is built on blocks that store thermal energy like melted chocolate chips in a muffin.
Firebricks offer low-cost storage for carbon-free energy | MIT News
news.mit.edu › firebricks-low-cost-storage-carbon-free-energy-0906

Sep 6, 2017 · These bricks could easily give up that heat to cold air being blown through the mass to carry away the heat for industrial use. But the bricks ...
Electrified Thermal Solutions | Joule Hive | United States
www.electrifiedthermal.com
It is a stack of electrically conductive firebricks in an insulated container. The system charges by running electricity directly through the bricks to joule- ...

The Rondo Heat Battery Is a Big, Brave Toaster - Treehugger
www.treehugger.com › News › Treehugger Voices
Sep 19, 2022 · The Rondo Heat Battery is described as a brave little toaster: "In essence, a toaster heating bricks to help decarbonize heavy industries ...

[PDF] Performance of firebrick resistance-heated energy storage for ...
www.sciencedirect.com › science › article › pii
Performance of firebrick resistance-heated energy storage for industrial heat applications and round-trip electricity storage. Daniel C. Stack* ...
Powerhouses: nanotechnology turns bricks into batteries | Energy
www.theguardian.com › environment › aug › powerhouses-nanotechnolog...

Aug 11, 2020 · The humble house brick has been turned into a battery that can store electricity, raising the possibility that buildings could one day ...
Energy storing bricks for stationary PEDOT supercapacitors - Nature
www.nature.com › nature communications › articles

Aug 11, 2020 · State-of-the-art energy storage materials are also produced from ... This synthesis utilizes a brick's open microstructure and thermal ...
VCharge Is Turning 'Hot Bricks' Into Grid Batteries | Greentech Media
www.greentechmedia.com › articles › read › vcharge-turning-hot-bricks-in...

Apr 2, 2014 · VCharge has a different plan for these electric thermal storage (ETS) units, one that turns them into megawatts of grid energy resource.
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Related searches
Energy Vault
Electrified Thermal Solutions
Energy storing bricks
Joule Hive
Thermal energy storage startup
Rondo Energy
Rondo Energy stock
Antora Energy

If anyone decides to try one of these brick based thermal energy storage systems, please let us know!

(th)

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#82 2023-01-24 14:45:22

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,844

Re: Thermal Energy Storage

For SpaceNut .... I asked Google to look for brick home thermal storage systems ...

Please note - This post is NOT about electricity storage!

It found what appear to be several examples, but it also found this paper:

https://pdf.sciencedirectassets.com/271 … ype=client

The above is a long url ...

The title is:

Performance of firebrick resistance-heated energy storage for
industrial heat applications and round-trip electricity storage

A scaled-up form of firebrick E-TES, referred to hereon as “firebrick resistance-heated energy storage”
(FIRES) [13][14], is a promising option for capturing and transferring surplus low-price electricity to the industrial
heating market, or for installation in power plants for regeneration of electricity. The temperatures and heat rates
necessary for coupling with industrial furnaces and power plants (1000-1700oC, 10s-100s MW) are already seen in
non-electric firebrick TES systems, such as the regenerative heat exchangers of blast furnaces [9].

It seems to me at least ** possible ** that NewMars members with suitable locations to work with could build small test instances of electrically heated brick thermal energy storage systems and try them out at modest expense.

Any electricity consumed heating a brick storage container would be released when power is out.

Power to flow air through bricks could be done with a battery powered fan, or by bicycle drive in a worst case scenario.

Please note: This post is NOT about electricity storage. The paper above is about industrial storage. This post is about using fire bricks to store thermal energy for the home, to heat the home when the electricity from the utility is not available.

What I'm imagining is a pile/stack/collection of bricks that can be heated by electricity (using resistance heating) and then fed with cold air from the inside of the home, for the purpose of heating the air for the comfort of residents.

There may be a commercial "furnace" already available for purchase, but if there is, I've not yet found it.

Every NewMars member with a home situation where power outage is possible would (presumably) be a candidate for such a system.

Reminder: This is NOT about storage of electricity!  This post ** IS ** about storage of thermal energy to heat a home when power is off.

(th)

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#83 2023-01-24 22:56:42

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 29,178

Re: Thermal Energy Storage

This sounds like the brick that lines a kiln that is used to fire ceramics.

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#84 2023-01-25 08:46:00

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 3,542

Re: Thermal Energy Storage

I think much depends upon how you intend to use the heat.  Brick heat storage could be used to absorb intermittent bursts of electricity to heat an oven, which is then used for cooking.  But how much cooking does an average family need to do?  I could see something like this working better at a large scale than on a smaller one.  Industrial scale cooking for example.  But it could work at the home level.  Any thermal leakage from the oven contributes to space heating.  The problem with storing high heat on a small scale is that insulation requirements can become excessive.  Storing energy in an oversized hot water tank may be a better option.  Water has excellent volumetric heat capacity.  And it is really cheap compared to any engineered material.

One idea that I have toyed with in the past, is a thermal energy storage system that uses intermittent electricity to heat rock or bricks in an insulated container.  A simple steam engine runs off of this heat and produces both electricity and hot water.  The electrical storage efficiency would be poor, as little as 20%.  But because the waste heat in the hot water is useful, overall energy efficiency of storage is close to 100%.  Exergy efficiency is perhaps 50%.  This is a relatively simple system to build.

Last edited by Calliban (2023-01-25 09:03:08)


"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."

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#85 2023-01-25 09:00:58

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,844

Re: Thermal Energy Storage

For Calliban re #84

Thanks for taking a look at this (relatively small) part of the overall topic.

What I'm thinking about is the unique (or at least rare) circumstance of a family living in the Northeast part of the United States, where natural gas is not readily available.  Such a family is limited to oil (imported) or electricity (from coal or other fossil fuel).

Let us suppose that such a family ** had ** a furnace to heat the home, but the furnace no longer works, and the family is dependent upon electricity to heat the home, to perform cooking, and to take care of all the other normal activities in a typical home.

When the power goes out, the home is dependent upon stored electricity in batteries, and when those are exhausted the home is magically transported back several hundred years, to a time when there was NO electricity, or oil, or gas.

What I've tried to envision is a way for a home owner dependent upon electricity to store up thermal energy ahead of a storm, when likelihood of a power outage is high.   

My idea was/is to stack bricks in such a way as to permit electric resistance heating ahead of a storm, and then air flow to remove thermal energy from the store gradually so as to keep the home above freezing for the duration of the power outage.

An advantage of such a system is that if there is a bit of solar energy available it can be stored in the brick stack, to be drawn upon using air flow, thus decreasing the amount of electricity that must be drawn from the utility to heat the home.

it seems to me that a volume about the size of a refrigerator might be able to store thermal energy for experimentation, to see if the idea has merit.

It seems to me that the object would need insulation to keep heat inside until it is needed, but there will inevitably be some flow through the walls, so the area immediately adjacent to the device would be warm.

(th)

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#86 2023-01-25 09:07:59

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,844

Re: Thermal Energy Storage

This post is a follow up to #85, but it is a very specific focus on a readily available test device for evaluation of stored thermal energy for emergency home heating.

Citizens of the Earth have built and installed countless ranges with ovens built in.  Many of these use electricity to heat the interior of (somewhat) insulated volumes, for the purpose of meal preparation.

My inquiry here is whether such an oven might be pressed into service as a thermal energy store.

Electric ovens are often still in perfect operating condition when they are removed for cosmetic reasons.

Let us suppose that one of those became available to an experimenter.

I am imagining that a load of suitable bricks could be elevated in temperature ahead of a storm. Then, when power is lost, the door to the oven could be lowered, and air inside a home flows into the bottom of the cavity and heated air flows out.

It should be possible (I'm hoping at any rate) to calculate the amount of thermal energy that might be stored in this way.

Update a few minutes later .... It is possible to imagine a basement wall lined with discarded but still useful electric ovens, filled with bricks to bank warmth ahead of a storm.  The electricity consumed banking energy would be saved when the power is out.   It should be possible to turn such an installation into a source of revenue, by carefully documenting the experiment for publication in a media which pays for source material.

Update a few minutes later ... NewMars forum has an opportunity to contribute to the store of practical knowledge, in addition to the wide ranging creative thinking for which the forum is justifiably famous.

Some (not all, but some) members of the forum are living in circumstances that permit a rigorous, well documented investigation of the practicality of storing thermal energy in used but still serviceable electric ovens, for the purpose of home heating during emergency situations.

Details of investments in equipment and specialized services (such as electricians) would be needed, along with measurements of energy inputs and outputs.

This forum is available for documentation of projects along these lines.

(th)

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#87 2023-01-25 11:57:32

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 3,542

Re: Thermal Energy Storage

tahanson43206 wrote:

For Calliban re #84

Thanks for taking a look at this (relatively small) part of the overall topic.

What I'm thinking about is the unique (or at least rare) circumstance of a family living in the Northeast part of the United States, where natural gas is not readily available.  Such a family is limited to oil (imported) or electricity (from coal or other fossil fuel).

Let us suppose that such a family ** had ** a furnace to heat the home, but the furnace no longer works, and the family is dependent upon electricity to heat the home, to perform cooking, and to take care of all the other normal activities in a typical home.

When the power goes out, the home is dependent upon stored electricity in batteries, and when those are exhausted the home is magically transported back several hundred years, to a time when there was NO electricity, or oil, or gas.

What I've tried to envision is a way for a home owner dependent upon electricity to store up thermal energy ahead of a storm, when likelihood of a power outage is high.   

My idea was/is to stack bricks in such a way as to permit electric resistance heating ahead of a storm, and then air flow to remove thermal energy from the store gradually so as to keep the home above freezing for the duration of the power outage.

An advantage of such a system is that if there is a bit of solar energy available it can be stored in the brick stack, to be drawn upon using air flow, thus decreasing the amount of electricity that must be drawn from the utility to heat the home.

it seems to me that a volume about the size of a refrigerator might be able to store thermal energy for experimentation, to see if the idea has merit.

It seems to me that the object would need insulation to keep heat inside until it is needed, but there will inevitably be some flow through the walls, so the area immediately adjacent to the device would be warm.

(th)

TH, what you are describing is a storage heater.  These are commercially available products and they have been around for a long time.  In theory, you could build them to whatever scale you choose.
https://en.m.wikipedia.org/wiki/Storage_heater


"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."

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#88 2023-01-25 12:37:50

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,844

Re: Thermal Energy Storage

For Calliban re #87

Thank you for providing a link to the Wikipedia entry on Storage_Heater(s) ... This is one of the few I've had (and taken) the time to read carefully, from top to bottom. This writing seems (to me at least) to have a bit of a UK flavor.

I am hoping that one or more NewMars members will investigate further, and report their findings.

***
Related ... I'm thinking ahead to heating/comfort requirements for cave dwellers on Mars .... The walls of the habitats may ??? be suitable for electrical heating (charge) and convection/radiation discharge.

The technology could be thoroughly tested on Earth.  There are plenty of locations where excavation of hill sides and selected mountain sides would match up reasonably well with the terrain of Mars.  The experience of cave dwelling could be explored and made increasingly agreeable.

There are many details to be worked out, such as providing for liquids and gases to enter, flow through and depart the habitats.

This forum has been engaged in discussion for over 20 years now.

The first post is dated: 2001-09-04 10:38:39

I'd like to see progress toward practical achievement.

A test Mars habitat can (most likely) be constructed in most existing Nations.  The chances of funding seem greater in the advanced Nations, but wealthy persons are found in every Nation.

(th)

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#89 2023-01-25 12:55:28

Terraformer
Member
From: Ceres
Registered: 2007-08-27
Posts: 3,826
Website

Re: Thermal Energy Storage

Hmm. Perhaps thermal storage would reduce the size requirements for heat pumps, if they operate continuously whilst heat demand is discontinuous? I.e. people only having the heating on for six hours in the evening could allow a significantly smaller ground loop if for the other 18 hours the heat is being banked.


Use what is abundant and build to last

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#90 2023-01-26 03:28:31

Terraformer
Member
From: Ceres
Registered: 2007-08-27
Posts: 3,826
Website

Re: Thermal Energy Storage

Houses in Britain are underheated -- benefits of insulation are mostly taken in the form of warmer houses rather than reduced gas use. If we want to improve quality of life at the same time as cutting gas consumption, insulation alone won't cut it, we need better heating systems. Whether that's district heating or ground source heat pumps I don't know. With the latter, consideration should also be given to underfloor heating, which uses lower temperature water than radiators do. If a dedicated heat pump is used for home heating and not expected to provide hot water, it can produce this lower temperature water with a significantly higher coefficient of power than one that replaces a boiler can achieve (or with a smaller loop).

The main problem with heat pumps appears to be the loop installation. I wonder if more and shorter vertical wells would work? 60m wells as they do now require segmented drills. Would the cost per metre be a lot cheaper if the well was only 8-10m deep?


Use what is abundant and build to last

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#91 2023-01-26 07:30:27

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,844

Re: Thermal Energy Storage

For Terraformer re #90

Just trying to follow your thought ....

Assuming the goal is 60 meters of vertical exposure, and 10 meters as the one-segment depth of a standard rotary drill, is it possible/practical to set 6 holes a small distance apart, to reach the 60 meters total?  I don't know the answer, but if anyone has a relative in the drilling business, they might be willing to hazard a guess.

And (related question but not unimportant).... is the total cost of the 6 holes less than the cost of one 60 meter hole?

***
For SpaceNut .... would you be willing to try the  bricks-in-an-old oven experiment?

You'd need:
1) An old still working oven discarded for cosmetic reasons
2) A device to measure power delivered to the oven
3) Wiring services of a qualified/certified electrician for 240 Service (in the US)
4) A supply of bricks suitable for the task (not sure best material or structure (ie, solid or holes))
5) A way of keeping meticulous track of every detail, to create a report
6) A way of making high quality pictures for publication in a pay-for-articles media

You don't need to wait for a storm to try this out.  You can load the bricks with thermal energy, and then open the oven door and record the room temperature.

(th)

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#92 2023-02-25 12:36:16

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 29,178

Re: Thermal Energy Storage

Sure, it's a do able experiment but the issue is the electrical cost to benefit I believe is not there. But will see what it can be. The house has seen a feb. temp on average of 20' F and I have used 55kwhr a day last year and was able to bring it down to 40kwhr for a day this year with the cost being $370 for its total bill for the month with of course last year being even higher.

Something that appears often is the average power use which is misleading for what is power generation and for its use as it does not take into account that you need surge current from the supply which when using average cannot be provided.

main-qimg-ffd9c9fe77c8ae461a9e33945142b101-c

The average home in the USA used 10,812 kWh per year. This is 1.234 kW average use. 63% of this is space heating and water heating. 777 Watts thermal power.

Space cooling is 9% or 111 Watts electrical. 4% for refrigeration adds another 49 Watts of cooling. Total cooling 160 Watts electrical. A triple effect absorption cooler with a COP of 1.8 requires a thermal source requires 288 Watts thermal. A heat source that generates 1,065 Watts thermal provides sufficient heat for all space heating hot water heating space cooling and refrigeration for a typical home.

Since this is using the thermal for heat the electrical is lots higher for an hour.

Solar is roughly a 3 hrs. span for half of the year in summer, while the winter is most likely only 2 hrs. to make use of for calculating storage size of thermal with the numbers of 777-watt thermal being probably low since my electrical is showing 15kwhr a day.

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#93 2023-02-25 12:42:29

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,844

Re: Thermal Energy Storage

For SpaceNut re #92

Thank you for taking up my question about possible use of a brick stack to hold thermal energy!

By any chance, does your utility offer reduced rate for electricity at certain times of the day?  If they do, then you could charge up the energy store during the lower cost period, and then draw from the store when energy cost is greater.

You would still need to power fans to move air through the store, but the heat would be coming from a time of day when energy cost was lower.

(th)

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#94 2023-02-25 17:20:05

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 29,178

Re: Thermal Energy Storage

No reduced rates as that was phased out a long time ago. Currently I am looking at all of the systems which one needs for a home as indicated and also the travel energy as well.

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#95 2023-02-26 02:45:57

kbd512
Administrator
Registered: 2015-01-02
Posts: 7,548

Re: Thermal Energy Storage

SpaceNut,

According to your pie chart, 76% of all energy usage involves direct heating and cooling.

45% Space Heating
18% Water Heating
9% Space Cooling
4% Refrigeration

The specific heat, c, in Btu per pound per degree Fahrenheit, for brick may vary from 0.20 to 0.26. Typically this variation is due to the impurities in the clay used to manufacture the brick. - Brick Industry Association

That's 840 Joules, per kilogram, per degree Kelvin.  1 Watt is also equal to 1 Joule per second, so a total of 3,600J or 3.6kJ is equal to 1 Watt-hour.  If you raised the temperature of 1kg of brick to 100K or 100C above ambient and could then extract the heat with 100% efficiency, then you'd have stored and then released about 23.3Watt-hours of energy.  If you use 5kWh per day of thermal energy for one of those applications and it can be reliably heated by at least 100C, then 215kg for a perfectly efficient system.  Each "standard" red brick, whatever that is (I've seen 2.25kg to 4kg per brick), weighs about 4kg, and 1 pallet is 500 bricks, so 1 pallet of a "brick thermal energy storage system" which can be reliably heated by 100C is storing about 46.6kWh.  I doubt you'd get more than 1/3 of that energy out in a real system, but 15.5kWh seems doable.  Cost per pallet seems to be $150 to $500 USD.

The specific heat capacity is defined as the quantity of heat (J) absorbed per unit mass (kg) of the material when its temperature increases 1 K (or 1 °C), and its units are J/(kg•°K) or J/(kg•°C).

Q = mcΔT
Q = thermal energy (in Joules)
m = mass (in kilograms)
c = specific heat capacity of the material in question (expressed in terms of J/kg•°C)
ΔT = change in temperature (from ambient temperature to whatever temperature the material is raised or lowered to, in Kelvin or Celsius)

Water stores 4,186 J/kg°C, so 418,600J for a 100C temperature increase, and 116.27Watt-hours, also assuming 100% efficiency.  If we had a perfect simple-cycle Carnot engine to convert that stored thermal energy from the Sun or geothermal well or nuclear reactor, into mechanical energy to perform work, then we can extract 58.14Watt-hours worth of work.  So, 401kg / 401L (106 US gallons) of water stores the same amount of thermal energy as a 2,000kg pallet of red clay bricks.

The bricks are solids, which is convenient, but I still think a tank of water will be easier to insulate and easier to use in a practical way.  A black plastic water tank that stores 100 US gallon potable water tank costs $364 from "National Tank Outlet", and it weighs 38lbs.  Unfortunately, max allowable temperature is only 48C.  That said, a 200 gallon tank from the same company is $500 and weighs 55lbs.  I would think that storing the water in a potable water tank and limiting its temperature to 48C would help keep the total cost of the system low, the water tank can store water for washing / cooking / cleaning and it's hand-portable when empty, whereas a pallet of bricks is not easily hand-portable.  Moreover, the thermal energy carrier can be pumped through a heat exchanger circuit to deliver electricity or mechanical work, using cold water as the cold sink.  If you limit the temperature to 48C, then there is little chance of thermal burns from fluid leaks.  Bury the tank in the ground and leave a small air gap for thermal insulation, and put a mylar wrap around the tank while you're at it.  That should be sufficient to keep the tank warm, even during the winter.  The tanks could also be stored in a basement, though.  Some thermal power will be lost pumping water through the circuit between the solar collectors on the roof or ground outside and storage tank(s).

A far cheaper solution would be 55 gallon plastic or steel drums.  Sometimes those are given away for free.  A "hot box" for the solar thermal collectors is something you've already built.  I guess the only question is how cheaply your cold sink can be built if you wish to generate electrical power by moving water through a heat exchanging circuit to drive an old washing machine or fan motor.  From there, you store it in discarded Lead-acid car batteries.  That's good enough for lights and a computer.

Cooking, especially during the winter, would be much more difficult to do using solar thermal.  That probably requires electricity, but Terraformer was telling us about how efficient the induction hot plates are, so that's an option.

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#96 2023-02-26 03:44:20

Terraformer
Member
From: Ceres
Registered: 2007-08-27
Posts: 3,826
Website

Re: Thermal Energy Storage

Re. Cooking, I've just bought an air fryer. So I expect the electricity bill to drop significantly. I actually can't remember if the oven has been used for anything that wouldn't fit in the (small) air fryer since Christmas. A lot smaller, less power, cooks faster. Like having a microwave that can crisp things up as they're meant to be.

Electricity is very good for when you want the heat to be targeted. Microwaves for example. Or electric blankets. And targeting it usually means you don't use much power either, so it's one area what electricity to heat actually makes sense.

Re. Thermal storage, water's great advantage is that you don't lower the temperature as it's used, since the cold water is drained away instead of going back into the tank. A solid pile of bricks doesn't have that; the temperature goes down as heat is extracted.


Use what is abundant and build to last

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#97 2023-02-26 08:15:16

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,844

Re: Thermal Energy Storage

For Terraformer re Community/Town heating/cooling project ...

I am following your initiative with great interest, but if you have published anything recently, I've missed it.

Please report on your interactions with the local Town Council.  You did report sending an email, but I have missed anything you might have reported subsequently. This initiative on your part seems (to me for sure) too important to allow to fail because some individual in a Town Council fails to pick it up and run with it. The idea deserves to be given a wider audience, such as the local newspaper if there is one, or the online replacement that may exist, if the traditional hardcopy news paper is gone, as seems likely.

This initiative on your part involves change, and not just a change from one brand of cereal to another, which is hard enough.  Every resident of the community is going to be involved at some point, to either approve the idea or reject it.   Rejection of the idea is FAR more likely, but the game has to be played through to find out what the final outcome will be.

(th)

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#98 2023-02-26 08:25:00

Terraformer
Member
From: Ceres
Registered: 2007-08-27
Posts: 3,826
Website

Re: Thermal Energy Storage

The trouble is, we have an election in May. After that, there's four years in which projects can be pursued without the disruption of a change in governing party. Have only emailed city councillors so far. Will email a district cabinet member today, hopefully there will be better luck.

Certainly looking forward to getting city councillors who respond to emails...

EDIT: Well, I've just emailed the cabinet member for "sustainable economic prosperity". I think that's what this falls under.

Last edited by Terraformer (2023-02-26 13:31:47)


Use what is abundant and build to last

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#99 2023-02-26 13:54:36

Terraformer
Member
From: Ceres
Registered: 2007-08-27
Posts: 3,826
Website

Re: Thermal Energy Storage

Well that was pleasingly quick smile

Dear []

Thanks very much for sharing your thinking. I agree about the preference for ground over air source - and supplementing with solar thermal (though the unit on our house has never functioned optimally) and the potential scheme that you cite is intriguing.

Indeed [] city council is about to undertake a Local Area Energy Plan (LAEP) to assess the district's energy demand and how it might be reduced by greater attention to energy efficiency; and how the remaining energy demand might be met from low-carbon sources.

I'm going to forward your email - minus contact details - to the officers working most closely on the matter for their consideration and to help inform the LAEP. I'm not going to promise that you're going to get a pilot study commissioned to consider your particular proposal in that [] triangle but I can promise that your suggestion will meet with open minds.

(I've briefly heard talk of looking at using water source heat pump energy from [] canal in another possible district heating scheme: that could be appropriate in [] too, of course.)

([] is doxable information; I'm wary about this sort of thing.)

So, the idea at least is in there now. Shame I couldn't get my councillors to pass it on for me, but we'll get rid of them soon enough.


Use what is abundant and build to last

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#100 2023-02-26 15:46:07

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 17,844

Re: Thermal Energy Storage

For Terraformer re 97, 98 and 99....

Bravo!  The message you reported shows more understanding of the problem to be solved, and awareness of alternative solutions, than I would have expected. Please keep us informed as things develop!  Best wishes for success in advancing your initiative!

Thanks too, for a glimpse of how the political process ** may ** work in your area. 

Changing the entire energy distribution network anywhere would be difficult, but I am guessing that doing so in a region with a history measured in hundreds if not thousands of years is going to be a doozy!

(th)

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