The Hydrogen fuel economy will not be viable.

[Marco]

I'd rather see district heating and cooling with ground source heatpumps. Lets say that in urban areas you bury a ground source heatpump machine room under the pavement for every 100 homes or so with it's own boreholes. Supplying a hot, warm and chilled coolant loop (warm for low temperature heating, hot for high temperature heating and domestic hot water, chilled for AC).

Will work in any climate, the AC load will allow you to run at net zero ground heat load across a year and you don't need a nuclear plant next door.

[nctnico]

I'm not sure whether that would work as well as expected. Ground has a poor heat conductance so you'd multiple boorholes (wells) and when the system goes off-balance you may overheat or exhaust a well. Not saying it is a bad idea perse but if the residual heat is there, it is better to put it to good use.

The nuclear power plant doesn't have to be next door. My hot water is coming from a power plant that is 20km away. With extension of the hot water network, it might come from much further in the future. It looks like they are already using residual heat from a nuclear power plant for district heating in China.

Edit: I don't see the 3 loop thing happening. Just having one loop with hot water is expensive enough already. For cooling use you might need to use a below freezing temperature for the water in order to achieve enough of a cooling effect. Which then requires the use of (potentially) toxic / hazardous anti-freeze agents.

I've been using district heating for over 20 years already for hot water and it works great. For floor heating, I have a mixing unit (common for floor heating) that mixes hot water with cold water from the pipes to ensure the water going into the floor isn't too hot. This mixing unit is nothing more than some pipes.

[SiliconWizard]

I'd rather see district heating and cooling with ground source heatpumps. Lets say that in urban areas you bury a ground source heatpump machine room under the pavement for every 100 homes or so with it's own boreholes. Supplying a hot, warm and chilled coolant loop (warm for low temperature heating, hot for high temperature heating and domestic hot water, chilled for AC).

I tend to have the same opinion.

[SiliconWizard]

Every realistic net zero alternative has more problems to overcome than hydrogen, not less. This is why hydrogen is going ahead regardless of all the nay saying, because the nay sayers aren't coming with real alternatives and 2050 is too close to listen to them.

"Net zero" is an horrific bullshit politician term anyway. It matches no reality.

[Marco]

"Net zero" is an horrific bullshit politician term anyway. It matches no reality.

Sure it does, kill all humans and the emissions from human activity drop to net zero pretty quick.

To what extent we can find a somewhat more palatable solution is an open question, but without fossil fuel all you really have to do is carbon capture from concrete production and you're pretty damn close.

[MadScientist]

This is the current cleanliness of EVs:



It depends where on earth you live and how much you drive before it overtakes the conventional ICE solution.

As for practicality, if you own your own home or have a guaranteed parking spot where you can plug it in every night, if most of your travel is under the range of you EV's battery with occasional longer trips, then it is a very practical solution in countries with a good support infrastructure.  Also, you will save a shit load on your petrol bill.

Anything short of my above paragraph, for now, just go for an ICE car.

I know several bev owners that merely use public fast chargers and neither isec domestic charging or slow chargers at all nor have several dedicated parking spots either

In most cases BEVs make better purchase than Ice.  Cheaper to run and service , better driving environment etc

[BrianHG]

This is the current cleanliness of EVs:



It depends where on earth you live and how much you drive before it overtakes the conventional ICE solution.

As for practicality, if you own your own home or have a guaranteed parking spot where you can plug it in every night, if most of your travel is under the range of you EV's battery with occasional longer trips, then it is a very practical solution in countries with a good support infrastructure.  Also, you will save a shit load on your petrol bill.

Anything short of my above paragraph, for now, just go for an ICE car.

I know several bev owners that merely use public fast chargers and neither isec domestic charging or slow chargers at all nor have several dedicated parking spots either

In most cases BEVs make better purchase than Ice.  Cheaper to run and service , better driving environment etc

Not to mention that here in Quebec, fast chargers charge so much for electricity that it costs less for petrol per mile/kilometer.  And even petrol prices here in Canada is among the highest in North America, so that's saying something.

[james_s]

can't imagine ever going back to an electric stove

if some of your bureaucrats get there way you may have to

I think that plan will be wildly unpopular, everyone that is even remotely serious about cooking uses a gas stove. I'll put a 5 gallon propane tank in the cabinet next to the stove before I'll get an electric stove.

[james_s]

I know several bev owners that merely use public fast chargers and neither isec domestic charging or slow chargers at all nor have several dedicated parking spots either

In most cases BEVs make better purchase than Ice.  Cheaper to run and service , better driving environment etc

When I was driving my dad's Tesla Y before we sold it I worked out that it cost about $10 to fill with 300 miles range, that's not bad at all, a comparable gasoline SUV would have cost around $80 at the time. Just for fun I calculated the fuel economy it would get if I charged it with my gasoline powered Honda EU2000i generator and I think it was around 18 mpg which is impressive when you consider that's a primitive air cooled engine with a carburetor and a ridiculous number of energy conversion stages.

The service thing is something my friends with EVs have been talking about lately. No oil changes, no coolant changes, no leaky heater cores, water pumps to replace, heater or radiator hoses to split, no radiator to leak. You can go tens of thousands of miles without any sort of maintenance at all. As someone who always seems to end up working on my car when it's cold and pissing down rain there is an appeal to that. I just don't drive enough anymore for it to make sense, and I like my car.

[Marco]

I'm not sure whether that would work as well as expected. Ground has a poor heat conductance so you'd multiple boorholes (wells) and when the system goes off-balance you may overheat or exhaust a well.

That's just a question of engineering, take worst case and add safety margin. Seasonal gas reserves can run out too, in theory.

Might be able to use an uninsulated coolant loop just below the pavement surface as a radiator to fix seasonal imbalance, otherwise a large forced air one.

[Marco]

Edit: I don't see the 3 loop thing happening. Just having one loop with hot water is expensive enough already.

With a distributed setup the pipes are much cheaper. 10k homes need a slightly bigger pipe than 100 homes, also propylene glycol ain't really toxic.

[Kleinstein]

A heat distribution network usually wants quite some temperature difference between the hot and cold side. So the hot water is rather hot, like 70-80 C.  Running power plant with such a high temperature for the cold side compromises on the efficiency producing electricity.  It works OK though for small, gas power motors, as they produce there waste heat in this range.

A heat distribution network with lower temperature difference needs thicker pipes and more powerfull pumps.
Central cooling works OK if there is a good sink, like a cool river. AFAIK such a system is in use in parts of Paris, though still with a heat pump.

[tom66]

There are some pilot projects in the UK that are providing heat to homes via a district heating system, usually the heat is generated by a heat pump system.

Heat pumps can still produce high temperatures, this is achieved by using a multi stage system.  Essentially, heating the water up twice, with the second loop using a different refrigerant optimised for higher temperatures. Such systems are usually uneconomical for homes, but are perfect for large industrial plants.   These plants usually supply heat at a cost metered by a heat meter.  Hot water can be supplied at any desired temperature by using a heat exchanger. 

I was listening to a report on the BBC regarding one particular system that had replaced oil boilers in about 500 homes in a smaller rural town.  The cost per unit of heat was identical.   In one particular vox pop, the woman said she preferred her old oil based system, but when questioned further, could not explain why.   At the end of the day, it's heat, so why would it matter?  In her mind she'd rather have to maintain an old oil boiler and order in oil every year (at considerable expense and subject to wild swings in the oil price) compared to just receiving heat at exactly the same cost. Some people confuse me.

[Bud]

In one particular vox pop, the woman said she preferred her old oil based system, but when questioned further, could not explain why.   At the end of the day, it's heat, so why would it matter?  In her mind she'd rather have to maintain an old oil boiler and order in oil every year (at considerable expense and subject to wild swings in the oil price) compared to just receiving heat at exactly the same cost. Some people confuse me.

Because a central heat generating plant is a single point of failure. I would say the same. My personal boiler I am responsible for it. If i do it well, my house is warm.

[themadhippy]

Such systems are usually uneconomical for homes,

and yet,not only do many parts of europe seem to use district heating  successfully,we also pay to export our rubbish to sweden, were its  burned and the heat used in? yep district heating systems

[tom66]

Because a central heat generating plant is a single point of failure. I would say the same. My personal boiler I am responsible for it. If i do it well, my home is warm.

Not really, a central plant could be just as reliable, could include multiple heat generators, backup oil/gas furnace etc.  There's no reason to believe a home heating system is more reliable.

Besides, there was no mention of reliability, just general "preference".  I'll try to dig the clip out.

[nctnico]

Edit: I don't see the 3 loop thing happening. Just having one loop with hot water is expensive enough already.

With a distributed setup the pipes are much cheaper. 10k homes need a slightly bigger pipe than 100 homes, also propylene glycol ain't really toxic.

I beg to differ. Remember I'm on district heating and a single connection is very expensive already. These systems don't consist of single loops. Blocks of homes are connected through sub-stations which distribute the hot water from the main loop into sub-loops. In a setup with 3 pipes, you'd need the sub-stations 3 times as well. The economy of scale is limited.

Because a central heat generating plant is a single point of failure. I would say the same. My personal boiler I am responsible for it. If i do it well, my house is warm.

No. I have been in the cold longer due to a boiler failing compared to district heating. Especially modern boilers are prone to failures due to the electronics. The fact is that the district heating systems are well maintained (preventive maintenance) and with crews on standby to fix problems. Spare parts readily available because the installation is highly standarised. Try to find a plumber to fix your boiler in the middle of the winter... Over here many won't help you if you don't have a service contract.

In addition: larger district heating networks have multiple heat sources and are setup using rings so there is redundancy.

[Marco]

In a setup with 3 pipes, you'd need the sub-stations 3 times as well.

I'm suggesting making the heatpump a station for on the order of a 100 homes, a distributed system which could be installed under the sidewalk rather than needing roadwork for the trunk distribution network. Drilling for a centralized system which could heat an entire city would be hard any way, you'd be looking at those 20 km deep boreholes they want to use for power stations.

It only needs pipes of sufficient diameter to feed the homes on it's local loop. Not the massive 20 km one with enough flow to warm an entire city.

[MadScientist]

District hearing as a new install is dead no one is considering it outside some weird legacy projects

[james_s]

If it was a new development I suppose it could be feasible but how do you meter it? I've never encountered district heating before, I don't whether it's ever been done in the US, maybe in some older cities.

[MadScientist]

No. I have been in the cold longer due to a boiler failing compared to district heating. Especially modern boilers are prone to failures due to the electronics. The fact is that the district heating systems are well maintained (preventive maintenance) and with crews on standby to fix problems. Spare parts readily available because the installation is highly standarised. Try to find a plumber to fix your boiler in the middle of the winter... Over here many won't help you if you don't have a service contract.

In addition: larger district heating networks have multiple heat sources and are setup using rings so there is redundancy.

Then you have crap home heating

I’ve now had 6 heating systems over four houses two gas based 4 oil fired ,downtime has been negligible amongst zero hours over 40 years. I have friends in a  “eco “ district heating projects which was completely abandoned due to service failures and unreliability and arguments over shared cost replacements

With solar pv beginning to dominate district style communal heating is dead as a Dodo

[Marco]

District hearing as a new install is dead no one is considering it outside some weird legacy projects

A system like I'm proposing is being considered in Greenwich. Though I doubt they are doing the triple loop, even though I think it makes a ton of sense. Most of the cost is in the ground work and using domestic hot water temperatures for heating in homes which don't need it is wasteful, if you do two loops you might as well do a third for chilled water for AC in the summer.

https://www.installeronline.co.uk/team-of-experts-lead-ground-breaking-greenwich-ground-source-heat-pump-study/

[tom66]

District hearing as a new install is dead no one is considering it outside some weird legacy projects

That's not even slightly true, the UK government is issuing grants for new installs, and proposing making it a requirement for new build estates over a certain # of houses.