4 ms·

From what I've read, winter heating consumes 40% of American households' energy budget. (A seldom-mentioned part of the big picture.) The heat extracted from li

From what I've read, winter heating consumes 40% of American households' energy budget. (A seldom-mentioned part of the big picture.) The heat extracted from liquifying air might be used for home-heating in a place like Vermont. I recall walking by a city telecom building getting rid of excess heat, in the winter, by opening big vents in the wall. Meanwhile, apartment buildings around it were burning fuel to keep warm. There are many ways we can do this stuff better.

gwbas1c 7y ago
I always wondered if mining crypto currency would be profitable enough to reduce my heating costs!
- nkrisc 7y ago
  Maybe! Just running my computer to game on raises the temperature in my office by about 3°F. My hunch is that a significant portion of that is from my monitor, as well.
dredmorbius 7y ago
District heating and cooling, and seasonal energy storage, are both approaches to an integrated energy system which distributes needs over space (district) and/or time (seasonal). District heating distributes heating (or cooling) from sites with an excess to sites with a need. Industrial processes are frequently utilised, though in sufficiently dense construction, office cooling can be a source of heating elsewhere. Many office towers have a net cooling load at all times of year, even under cold ambient conditions. Seasonal energy storage banks heat from warm periods of year for use in cold periods. This may be completely adequate for general space heat, and sufficient for a large portion of higher-intensity heating (e.g., water). Storage may be in geological structures, if those are sufficiently stable (ground-water migration will also migrate out your stored heat), or constructed energy storage facilities, often little more than well-insulated water tanks with vertical thermal stratification. Thorstein Chlupp of Rienna LLC designs zero-net-energy homes in Fairbanks, AK, utilising seasonal thermal energy storage. His videos run long, but are exceedingly comprehensive and explain in detail design and construction decisions. Seasonal storage is covered here beginning at about 1h18m, to about 1h30m: https://invidio.us/watch?v=AtHkvpRI6fc https://invidio.us/watch?v=AtHkvpRI6fc https://en.wikipedia.org/wiki/Seasonal_thermal_energy_storage https://en.wikipedia.org/wiki/Seasonal_thermal_energy_storag...
- kardos 7y ago
  Storing heat in a big water tank is certainly an option but it has drawbacks. I'm looking forward to developments in thermal storage in phase change materials and also storage via endothermic reactions.
  - undreren 7y ago
    We do this in Denmark for storage of district heating water. They are called "varmeakkumulatortanke" in Danish, roughly translated to "heat accumulator tanks". They are insulated like a thermos (but more efficiently), and since they are really big, they have small surface area compared to their volume. It is a VERY efficient way to store heat over shorter periods, like a week or so, and it helps making power plants more cost efficient. The best way to make it efficient for long term storage (like seasonal storage) is to 1. Make them huge 2. Make them ball shaped 3. Put them underground There has been talk of tryibg this out in Denmark. Almost all our powerplants (i.e. the not-really-old ones) are combined heat and power plants, and because we use district heating water to create a vacuum behind the power producing turbines turbines (instead of sea water) we go from a theoretical limit on the energy efficiency of around 60% to 98%, as we do not pump out the excess heat into the sea. Newer combined heat and power plants have an energy efficiency of around 95% to 96%. The trade of is a slightly lower vacuum, meaning less production of power. However, we can scale up heat production to reduce costs of running power plants when energy prices are low (or even negative).
    - kardos 7y ago
      > 1. Make them huge That more or less puts it out of reach for homeowners, condo dwellers, etc. You need a big expensive coordinated project to get that built. Meanwhile, as an analogy, solar panels are within reach for a homeowner. Seasonal thermal storage will need to be more modular / modest sized for it to be widely applied. The potential for storing heat by forcing endothermic reactions (where you later extract it by running the reaction in reverse) has a lot more potential to be "homeowner sized".
      - 7y ago

gwbas1c 7y ago

I always wondered if mining crypto currency would be profitable enough to reduce my heating costs!

nkrisc 7y ago
Maybe! Just running my computer to game on raises the temperature in my office by about 3°F. My hunch is that a significant portion of that is from my monitor, as well.

dredmorbius 7y ago

District heating and cooling, and seasonal energy storage, are both approaches to an integrated energy system which distributes needs over space (district) and/or time (seasonal). District heating distributes heating (or cooling) from sites with an excess to sites with a need. Industrial processes are frequently utilised, though in sufficiently dense construction, office cooling can be a source of heating elsewhere. Many office towers have a net cooling load at all times of year, even under cold ambient conditions. Seasonal energy storage banks heat from warm periods of year for use in cold periods. This may be completely adequate for general space heat, and sufficient for a large portion of higher-intensity heating (e.g., water). Storage may be in geological structures, if those are sufficiently stable (ground-water migration will also migrate out your stored heat), or constructed energy storage facilities, often little more than well-insulated water tanks with vertical thermal stratification. Thorstein Chlupp of Rienna LLC designs zero-net-energy homes in Fairbanks, AK, utilising seasonal thermal energy storage. His videos run long, but are exceedingly comprehensive and explain in detail design and construction decisions. Seasonal storage is covered here beginning at about 1h18m, to about 1h30m: https://invidio.us/watch?v=AtHkvpRI6fc https://invidio.us/watch?v=AtHkvpRI6fc https://en.wikipedia.org/wiki/Seasonal_thermal_energy_storage https://en.wikipedia.org/wiki/Seasonal_thermal_energy_storag...

kardos 7y ago
Storing heat in a big water tank is certainly an option but it has drawbacks. I'm looking forward to developments in thermal storage in phase change materials and also storage via endothermic reactions.
- undreren 7y ago
  We do this in Denmark for storage of district heating water. They are called "varmeakkumulatortanke" in Danish, roughly translated to "heat accumulator tanks". They are insulated like a thermos (but more efficiently), and since they are really big, they have small surface area compared to their volume. It is a VERY efficient way to store heat over shorter periods, like a week or so, and it helps making power plants more cost efficient. The best way to make it efficient for long term storage (like seasonal storage) is to 1. Make them huge 2. Make them ball shaped 3. Put them underground There has been talk of tryibg this out in Denmark. Almost all our powerplants (i.e. the not-really-old ones) are combined heat and power plants, and because we use district heating water to create a vacuum behind the power producing turbines turbines (instead of sea water) we go from a theoretical limit on the energy efficiency of around 60% to 98%, as we do not pump out the excess heat into the sea. Newer combined heat and power plants have an energy efficiency of around 95% to 96%. The trade of is a slightly lower vacuum, meaning less production of power. However, we can scale up heat production to reduce costs of running power plants when energy prices are low (or even negative).
  - kardos 7y ago
    > 1. Make them huge That more or less puts it out of reach for homeowners, condo dwellers, etc. You need a big expensive coordinated project to get that built. Meanwhile, as an analogy, solar panels are within reach for a homeowner. Seasonal thermal storage will need to be more modular / modest sized for it to be widely applied. The potential for storing heat by forcing endothermic reactions (where you later extract it by running the reaction in reverse) has a lot more potential to be "homeowner sized".
    - 7y ago