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What sort of heat transfer rate are we looking at, for a given temperature difference? Obviously its going to take time for 30c water to heat a 25c borehole...

One thing we could do with geothermal heat is to circulate it during the summer to heat the entire borehole rather than just the bottom. Then draw the heat out during the winter. Improved capacity factor.

As for car park heat collection, there are four sizeable car parks in central Carnforth, the three supermarkets and the railway station. Looks like they could be enough for the centre?

Well, we're not allowed to have houses there in case they want to mine gravel for 22nd century motorway construction, might as well make use of it for something that benefits the town...

What I have in mind though are smaller such schemes. Admittedly greenfield solar collectors will probably be cheaper than over car parks and roofs, even flat ones. But the space for boreholes is certainly not hard to find. I suppose the solar thermal collectors would be angled for summer?

The other issue is that running the mains along the road means digging up the roaad. Unfortunately there's a gas main under the townpath until I think the canal turn, but if there's room it would be far less disruptive. But past the canal turn (next to where the town gas was made, hence the gas lines) I think it is clear and would not be a bad place to run a hot water mains if so. Certainly they dont trim the trees the way they're supposed to near gas lines in that section.

I'd suggest the locations to look for are (1) large heat users that are (2) located next to open spaces for ease of borehole drilling and which (3) can be connected to domestic customers relatively easily (no long stretches that involve shutting down roads to install pipes).

In the case of Carnforth, I can see 2/3 -- the triangle I've mentioned before (primary school field, hotel and civic hall and school and church located around the edge, terraced houses also along it); the high school (large playing field, school and swimming pool adjacent); and possibly the area next to the train station (car park for boreholes, station hotel as anchor customer,  terraced homes with alleys for running piping). Aside from that, there are various school fields and parks and car parks throughout the Victorian centre of town, an area that benefits from alley access (the cold water supply presently runs under these also).

If there's a mass buildout, we could manufacture pre insulated pipes? I know a cold system doesn't necessarily require much, but I'd like to futureproof it so we can do things like seasonal heat storage and supply heat at 25c instead of 10c...

EDIT: One problem that occured to me in cases where there are no convenient alleys -- gas pipes are routed under streets. Any attempt to run pipes under the pavements would have to deal with the connections to the houses every 5-10m. Obviously not a problem if the entire street switches over at once, but that is likely to take a level of coercion that will be difficult to achieve. Perhaps we could compulsory purchase easements right down the middle of the block and make an alley...

From 2013 -- Cost analysis of district heating

Their estimated costs for installation were around €2000 per house in prebuilt areas. It shouldn't be an especially expensive infrastructure to construct -- £2-400/m? -- because it's "just" trenching and piping, no messing around with high pressure gas. If it cost £2500 per house to put the pipes in, about £75 billion for all the homes in the country. Several years of gas bills, not a particularly large amount relative to other plans for a clean energy transition, and would be largely privately funded. And of course, costs will depend on the type of housing -- terraced houses with alleyways to run the pipes without disruption could be a lot cheaper to supply, whilst being the biggest beneficiaries due to limited space for more individual systems.

EDIT: I didn't realise how small the domestic distribution system would need to be. A litre of water cooled through 10c (say, 35 to 25 Celsius) would give up 40kJ of heat.  A house might only need to tap 0.1L/s then, so a street of forty houses needs to provide 4L/s at peak. At 0.1m/s flow, that's a pipe ~25cm wide. We can easily fit that in alleys or under pavements.

And, of courses, one major benefit of external insulation is that the heavy thermal massing is within it. The house itself can store a large amount of heat, once it has warmed up. Perhaps there is a way we can speed the heat transfer along, helping to cool in summer and store heat in winter? A mid terrace might have 25cm of stone/brich on either party walls (the one I grew up in is 50cm narrower on the inside -- those walls are thick, whatever Max Brooks thinks in his zombie stories). At about 7m long by 6m tall, that's ~20 cubic metres. At 1.6MJ (~0.5kWh) per cubic metre, cooling down by 2 degrees would put 20kWh of heat into the house from just the party walls. It will take time for the house to cool. Which means also that once the walls are warm, heating energy will not be taken by them, only by the air and furniture.

Ventilation is important, and at 100L/s air exchange (good ventilation, rarely achieved) and freezing temperatures outside we're talking ~2kW of heating needed. I'd suggest shrinking our windows slightly to make it easy to put in vents... raising the ground floor window of a terrace by 20cm isn't going to screw it up super badly from an aesthetic standpoint, and means we can run pipes and cables into the house without needing any hatchet jobs. Recovering 75% of the heat would make it a far more manageable 500W heating. Or none, if there are 4 or 5 people in the house.

I have made a new topic in home improvements to talk about home thermal storage -- https://newmars.com/forums/viewtopic.ph … 38#p225338

Hot water tanks are standard in a lot of houses. It's an oversized one that's the non standard part here. Phase change thermal storage is available for use with heat pumps.

For fridges and freezers, adding in water should not be a particularly difficult thing to do. And hot water dispensors are off the shelf too, though probably need some better insulation.

More excited about this kind of energy storage than others because of this. It's not a massive leap from what is already there, and multi-tariff deals from energy suppliers that provide cheap off peak energy, especially if flexible (so you can buy wind energy when it's basically being dumped onto the grid) should provide a strong incentive to install it.

Calliban,

Washers and (tumble) dryers primarily use heat also. There's no good reason to use electricity to heat the water over simply plumbing it in to the hot water tank. I think its 400W for just the spinning? So a load might take 200Whr. Likewise, kitchens should not require much storage microwave and oven aside, since near boiling water can be stored and only requires a small amount of power to keep it hot (or phase change materials?). The baseload electricity demand for a house that's optimised heat storage would be significantly lower than it is now. Maybe we could get away with about a kWh a day...

Compressed air takes time to cool. How does this affect its use for transmission? Could a series of windmills directly pump air into a chamber that is then tapped for steady power? Thinking about underwater air pipelines here.

In another thread, Calliban mentioned hydraulic accumulators:

I am a little confused by the temperature rise here. If water were used, then a 1 deg. change in temperature would store 4kWh of sensible heat. Surely the heat of compression would end up being lost to the hydraulic fluid, if there is no insulation between them?

But also, the compression is taking place within the tank. Does this offer opportunities to better capture the heat of compression, given the greater surface area available vs. a compressor?

I now have a goal of converting a camper van once I have a drivers license and some money lol   Seems to be the best way to go about a testbed for the Neo-dymaxion house. At least, one that could be affordable to me within a couple of years...

IDK how much research has already been done on this, but a small tank could be jacketed with paraffin or some other phase change material? It may require fins to be installed in the tank itself to provide fast enough heat transfer. If we can get away without having to add intercoolers and a separate heat store, the system will be considerably simpler and should be cheaper. The ohase change material may have to be installed within the tank itself to achieve this. Or for that matter at the opening... hmm.

How much weight can concrete withstand?

Wondering if old quarries could be a good place for this. Quite a few holes in the ground that need filling in. Though I suppose in that case they normally get fillled in by water. Build an artificial lake bed to store air before that happens?

Basically a manmade version of the caverns that are used by a lot of systems today.