More or Most efficient hydronic heating basic unit? (natural gas)

[langwadt]

Do you mean like in Iceland, where nearby volcanoes have heated the earth up hot enough to heat groundwater and spring water toasty warm?

That's one thing, it's like the very real geothermal i.e., utilizing heat from the core of Earth. If you have such source of energy, you may not need a heatpump at all, just circulation pump and heat exchangers work.

But usually, "ground source heat pump" does mean a mix of a tiny bit of Earth core heat, but mostly solar heat stored by the massive amount of bedrock/soil around the year. These pumps do not require active volcanoes but work anywhere. You just drill some 200m (700 feet) hole to extract the energy. The temperature in that hole follows the yearly average of that climate pretty well. It heats up maybe a degree or two in summer, and cools down maybe a degree or two during winter. Pretty steady heat source. By pumping from say +5 to +35, COP is easily like 5. Great for heating in cold climates. Yes, it uses electricity too but not much. Instead of drilling a hole, if you have a lake or a river which does not freeze during winter, ground source heat pump can extract energy from that. Much cheaper to install.

But not worth the investment either if burning fossils is indirectly subsidized by 300%.

here most geothermal is not vertical, it is horizontal over a larger area either plowed or digged down to ~1m

I've heard some use a well and circulate ground water, but there is probably lots of regulations because potentially
pumping stuff into the ground water would be bad

 

[Siwastaja]

here most geothermal is not vertical, it is horizontal over a larger area either plowed or digged down to ~1m

I've heard some use a well and circulate ground water, but there is probably lots of regulations because potentially
pumping stuff into the ground water would be bad

Yeah, depends on the soil. Horizontal is great in clay soil. Vertical is the way to go when you are directly on the top of bedrock; thermal conductivity of rock is OK for heat pumping, but it's impractical to drill in any other direction than down. AFAIK, sand is not the greatest soil type for ground source.

At least here, all modern (or at least legal) ground source systems use ethanol-water mix instead of glycol so that the leak does not pollute ground water. Not even propylen glycol is allowed. Another, possibly the actual reason for using ethanol is lower viscosity because pumping losses in such long piping (possibly in excess of a kilometer!) are significant.

Nowadays it's sometimes hard to get permission to build ground source systems here especially in the presence of ground water but I think it's more about politics than any actual reasoning. I.e., ground source companies have not invested in lobbying hard enough, which is what you need to do if you want to run any business in the Not-Allowed-Land.

Having a river or a big lake nearby is really the most optimal case for low-cost high-efficiency ground source heat pumping but few have that luxury available.

[David Hess]

I had just assumed that CO2 was produced the same way, apparently not, at least not in large quantities. The talk I've seen of storing CO2 pulled from the environment seem to focus on the storage aspect when it seems the focus really ought to be on the capturing aspect because if we can't pull enough of it out of the air to meet industrial needs then there is no point in trying to store it. I had always assumed that using CO2 was a zero sum game since I figured it was pulled out of the air to be put in tanks and eventually let back out into the air.

I thought the same thing for a long time, but as IanB points out, CO2 is a massive byproduct of hydrogen production from methane for production of fertilizer and petrochemicals, so that is the largest source.

It also seems silly to use natural gas to make hydrogen when it can be made from electricity and the plants producing it for industrial use can be conveniently located near cheap electricity.

It just comes down to economics.  The electricity needed to produce enough hydrogen for ammonia (fertilizer) production would be massive, and unless you want to burn fossil fuel to supply it, is really only practical with nuclear power.

If nuclear power is acceptable, then there are better ways like high temperature electrolysis of water, or the surfer-iodine cycle.

Of course politics trumps economics all the time, except when it does not, and ultimately it never does.  But that is what we are discussing.

[IanB]

I had always assumed that using CO2 was a zero sum game since I figured it was pulled out of the air to be put in tanks and eventually let back out into the air.

Not a zero sum game at all, hence all the fuss about climate change. Lots of carbon is bound up in fossil fuels like coal, oil and gas, where it is safely out of the way and not contributing to the greenhouse effect. But over the years, with the burning of these fuels, lots of carbon is being put into the atmosphere as CO2, which is a problem. It is not possible to get the CO2 back out of the atmosphere once it has been released, but it is possible to stop adding to the problem. Hence the need to switch to renewable energy sources, and to capture CO2 from the burning of fossil fuels and prevent its release.

[james_s]

Not a zero sum game at all, hence all the fuss about climate change. Lots of carbon is bound up in fossil fuels like coal, oil and gas, where it is safely out of the way and not contributing to the greenhouse effect. But over the years, with the burning of these fuels, lots of carbon is being put into the atmosphere as CO2, which is a problem. It is not possible to get the CO2 back out of the atmosphere once it has been released, but it is possible to stop adding to the problem. Hence the need to switch to renewable energy sources, and to capture CO2 from the burning of fossil fuels and prevent its release.

I'm not talking about CO2 resulting from burning stuff, I'm talking about the vast quantities of CO2 that are used for industrial purposes. Even just what is used in soft drinks must be non-trivial when looking globally.

[Marco]

It will be much more expensive due to technical challenges. For instance first hydrogen transport 116m ship will have just 1250 m³ capacity. Excerpt from article:

The first pilot ship is small and expensive? You don't say. The trucking industry is already making liquid hydrogen fuel tanks, huge amounts of practical development going on there with relatively little subsidy. Liquid hydrogen is piggy-backing on experience from LNG.

Trucking much like seasonal storage is where the rock meets the hard place ... liquid hydrogen is expensive, fine. Present a cheaper alternative ready to provide decarbonization in three decades. Nuclear is tentatively cheaper than seasonal storage with renewable, but for trucking you need power to liquid of some form and hydrogen has the greatest technical readiness. The promises from governments currently require hydrogen, it's that simple. Expensive can be done, fairy tales don't solve shit.