Geothermal pluses and minuses

[mooncliff]

If only it were so easy and cheaper...

http://www.scientificamerican.com/bl...art-2011-06-20

[Starving Steve]

Re: Geothermal pluses and minuses

I had thought that one could drill into the Earth, just maybe 40 feet ( 12 metres or so), and one would have rocks warm enough to heat an apartment house or condo building.

Within one block of Victoria General Hospital in Victoria, on Hemleken Road, there is a condo-complex being built now that is going to be heated by geo-thermal heat. Its foundation looks to me to be about 40 feet sunk into the Earth, at most. So how is this going to work, or would it work? I was told that geo-thermal is quite popular in Europe and also in Toronto, and this concept would work well in Victoria, BC.

What do you think? Is this going to work? I am a pragmatist in the tradition of Stalin, so I favour whatever works and works well. Results matter.

[Ghent12]

Re: Geothermal pluses and minuses

Geothermal is probably pretty good for thermal control of housing or other buildings, but it is a complete bust for electricity production. Thermal control applications would certainly be worth doing a bona fide investment analysis on.

Geothermal electrical power, or at least the type generated in some parts of California, might as well be called "earthquake plants" instead of power plants. It's not just the drilling that can set off "mini-earthquakes" as the intellectually dishonest Scientific American article implies, but the routine operation of the plant which sends water down into the earth to heat it up into steam and then collects it to produce power. This causes tremendous changes in the rocks that the water travels through and absorbs heat from, especially contractions near the point where liquid water enters. These set off numerous earthquakes.

[LorenS]

Re: Geothermal pluses and minuses

http://www.livescience.com/9777-eart...-projects.html


My cousin uses a geothermal heatpump to heat/cool her house. It's very efficient.

Combined with something like the IceEnergy system it could significantly reduce base load demand.

http://www.ice-energy.com/

[c1ue]

Re: Geothermal pluses and minuses

The problem with geothermal is that it uses tremendous amounts of water.

Fresh water is already at a premium worldwide.

Sure, pretty much all other fossil fuel plants also require water; it is not clear the relative levels vs. geothermal are.

[thriftyandboringinohio]

Re: Geothermal pluses and minuses

http://www.livescience.com/9777-eart...-projects.html


My cousin uses a geothermal heatpump to heat/cool her house. It's very efficient.

Combined with something like the IceEnergy system it could significantly reduce base load demand.

http://www.ice-energy.com/

There are two meanings for "geothermal" in common use today.

For individual homes and single buildings, a "geothermal" system is a heat pump that circulates water through a long loop of buried pipe. It exploits the constant ground temp below the frost line, making a big improvement to efficiency both for heating and cooling by the electric heat pump. That's probably what your cousin has.

At the power plant scale, "geothermal" means extracting large amounts of energy as the primary fuel for a steam turbine generator with output over 100 million watts. They exploit volcanic activity like hot springs, shallow magma domes, geysers, stuff like that. Huge reliability challenges due to high temps and corrosive chemicals at the heat source, and are really experimental pilot plants working through the issues.

Residential geothermal heat pumps work great; they are well-proven and only slightly different than any other heat pump system. The utility scale plants are experimental and difficult (but sure look like a good idea if we can engineer solutions to the problems).

[Starving Steve]

Re: Geothermal pluses and minuses

My computer does not run videos, so a few important questions about the ice-energy system:

a.) Does this use frozen (solid) water, I mean common and ordinary ice? Or does this use frozen (solid) anything, like ammonia?

b.) Does this employ the principle of latent heat of freezing; i.e, heat given-off as water ( or whatever ) freezes?

c.) Does this employ the principle of latent heat of melting: i.e, the heat absorbed to change a frozen solid ( ice or whatever ) into a liquid like liquid water?

d.) Do you use this ice system to heat and cool homes and buildings? Could one use the ice system alone and not supplement it with back-up heating and cooling systems?

e.) What does the ice system cost to install? And does it work well in extreme climates? Do you have a cost/benefit analysis?
Does this system simply depend upon ideal weather conditions and sucking-off government subsidies to become viable, much like solar energy and wind-energy systems do now?

f.) Is the ice system part of another energy system such as a geo-thermal energy system? In this way, does the ice system simply act as an energy storage system? And if so, who pays for this and how?

[thriftyandboringinohio]

Re: Geothermal pluses and minuses

My computer does not run videos, so a few important questions about the ice-energy system:

a.) Does this use frozen (solid) water, I mean common and ordinary ice? Or does this use frozen (solid) anything, like ammonia?

b.) Does this employ the principle of latent heat of freezing; i.e, heat given-off as water ( or whatever ) freezes?

c.) Does this employ the principle of latent heat of melting: i.e, the heat absorbed to change a frozen solid ( ice or whatever ) into a liquid like liquid water?

d.) Do you use this ice system to heat and cool homes and buildings? Could one use the ice system alone and not supplement it with back-up heating and cooling systems?

e.) What does the ice system cost to install? And does it work well in extreme climates? Do you have a cost/benefit analysis?
Does this system simply depend upon ideal weather conditions and sucking-off government subsidies to become viable, much like solar energy and wind-energy systems do now?

Steve, I read LorenS link and you have it exactly correct. It freezes ice at night and melts it during the day. Like any battery there must be losses, so it only makes economic sense if the owner can get cheaper power during off-peak.

By the way, have you ever wondered why your air conditioner is rated in "tons"? The very first refrigeration units were sold at the turn of the last century and purchased by people to manufacture blocks of ice delivered to home ice-boxes. Those buyers only cared about how many tons of ice they could make in a day. The engineers defined a standard thermodynamic cooling "ton" to describe that ice-freezing capacity. To this day we buy our air conditioners rated in "tons".

[Starving Steve]

Re: Geothermal pluses and minuses

Steve, I read LorenS link and you have it exactly correct. It freezes ice at night and melts it during the day. Like any battery there must be losses, so it only makes economic sense if the owner can get cheaper power during off-peak.

By the way, have you ever wondered why your air conditioner is rated in "tons"? The very first refrigeration units were sold at the turn of the last century and purchased by people to manufacture blocks of ice delivered to home ice-boxes. Those buyers only cared about how many tons of ice they could make in a day. The engineers defined a standard thermodynamic cooling "ton" to describe that ice-freezing capacity. To this day we buy our air conditioners rated in "tons".

One of the industries in the very early 20th Century was ice harvesting from frozen lakes. In Minnesota, for example, ice was harvested from Lake Superior in winter and early spring and sent, packed in straw, southward by train to Minneapolis-St. Paul to use to cool homes during the summer. Everything was very inefficient one-hundred or more years ago, so there was no shortage of work to do.

Duluth-Superior one-hundred years ago had jobs in ice-harvesting, ice shipping, ice delivery, coal delivery, coal trans-shipment from ships to trains, iron ore trans-shipment from trains to ore boats, grain storage, grain trans-shipment from trains/wagons to ships, paper production, steel production, paper shipping, steel shipping, metal-fabrication, warehousing, wholesaling, jobbing, power-generation, newsprint delivery, newspaper production, newspaper delivery, bridge management, railyard management, general railroad work, not to mention lumber-milling, brewing, baking, fishing, and food-processing. The decline in Duluth-Superior in the years that followed (especially 1946 to date) was emblematic of what happened in dozens of other ports along the Great Lakes and throughout the North-eastern U.S. Understanding what happened to employment in the rust-belt is key to understanding what is has happened in the rest of the U.S. and Canada, especially now during the Great Recession.... Hence, we are left with an America and Canada of hamburger-flippers, realtors, bankers, and vets. The rest of the work is done by robots, computers, machines, or out-sourced especially to China.

One more interesting fact: On the Great Lakes after the opening of the St. Lawrence Seaway in 1959, ship traffic increased. Tonnages of shipment increased. Productivity increased. Ocean-going ships were accommodated. Shipping and trade with the entire world began. Costs went down. And guess what: Paradoxically, employment in the Great Lakes region disappeared. After 1959, the out-migration from the Great Lakes region began in earnest.

In the 1960s, the port of Duluth-Superior had a large ship, either arriving or departing every five or ten minutes during the summer months... Yet, the jobs vanished. The population of Duluth and Superior decreased by about 20%.

[thriftyandboringinohio]

Re: Geothermal pluses and minuses

One of the industries in the very early 20th Century was ice harvesting from frozen lakes. In Minnesota, for example, ice was harvested from Lake Superior in winter and early spring and sent, packed in straw, southward by train to Minneapolis-St. Paul to use...

My father lived in western Minnesota over by Fargo-Moorehead, was born in 1918 and was a kid in the 1920s and 1930s. He and the neighbors cut ice for their own use from local lakes. They kept it in the barn under a big pile of saw dust and it lasted through August. As poor farmers (subsistance farmers, really) they wanted ice for the kitchen ice-box but saw no reason to pay money for something they could get for free, just a few miserable days of hard work with a saw on a frozen lake.

[wayiwalk]

Re: Geothermal pluses and minuses

My father lived in western Minnesota over by Fargo-Moorehead, was born in 1918 and was a kid in the 1920s and 1930s. He and the neighbors cut ice for their own use from local lakes. They kept it in the barn under a big pile of saw dust and it lasted through August. As poor farmers (subsistance farmers, really) they wanted ice for the kitchen ice-box but saw no reason to pay money for something they could get for free, just a few miserable days of hard work with a saw on a frozen lake.

Sounds like my long term plan for my off the grid post apocalypse home adjacent to a lake for fresh water, ice for cooling a storage freezer built into the earth, etc...but in a more comfortable climate than minnesota :P

[lektrode]

Re: Geothermal pluses and minuses

The problem with geothermal is that it uses tremendous amounts of water.

....

not sure about water use at the other geothermal plants, but it doesnt sound like this one uses much:
http://www.punageothermalventure.com/PGV
"...The 30-megawatt (MW) PGV plant uses air-cooled condensers and noise reduction enclosures. It is a low-profile plant, 24 feet high, and has near zero emissions. One hundred percent of its geothermal fluid and gas is reinjected into the deep earth..."

[lektrode]

Re: Geothermal pluses and minuses

There are two meanings for "geothermal" in common use today.

For individual homes and single buildings, a "geothermal" system is a heat pump that circulates water through a long loop of buried pipe. It exploits the constant ground temp below the frost line, making a big improvement to efficiency both for heating and cooling by the electric heat pump.

the primary benefit of using a mechanical refrigeration process to make heat is the 'coefficient of performance' (COP)
ie: put one KW of electric into a resistive heating element and you get 3412 btu of heat out of it..

put same KW of electric into the refrig compressor (heat pump) and you get somewhere between 2.5 and 5 or even 6 btu of heat out of the process of evaporation/boiling of the refrigerant (collection/concentration of latent heat via the phase-change from liquid to gas) then compressing the 'hot' gas and dumping the collected heat into some other space = why ground-source heatpumps work so well (in colder climates) = there's always a bunch of heat available 5or6 feet down, where the temp stays typically in the 50's year round.. and then add the benefit of the COP of the refrig process and you get a double winner, in terms of efficiency.. works great in the summer too, since the _mass_ of the earth can suck up a lot more heat, per cubic yard, than air can

this phenomena is also why a FULL refrigerator is more efficient than an empty one....

Residential geothermal heat pumps work great; they are well-proven and only slightly different than any other heat pump system.

yes, the main diff = vastly more expensive than an air-to-air heatpump, because ya gotta drill/dig/bury all that pipe for the evaporator/condensor coil, vs just blow air thru a finned-tube assembly that sits on a pad...

but when it goes much below freezing (40degF even), an air-to-air heatpump quickly gets to be less efficient

The utility scale plants are experimental and difficult (but sure look like a good idea if we can engineer solutions to the problems).

they're not all that 'experimental' anymore: http://www.punageothermalventure.com...thermal-Energy
but the politix of it make it more difficult than it ought to be...
again, the luddite brigade would rather US fight wars over oil than deal with stuff that works but has a few issues they cant seem to wrap their heads around without phreakin out....

[lakedaemonian]

Re: Geothermal pluses and minuses

I'm no SME on geothermal.....but I think Iceland and New Zealand have developed some geothermal.

Here's a wiki for NZ:

http://en.wikipedia.org/wiki/Geother...in_New_Zealand

I think I recall hearing about some places in NZ like Rotorua maybe that have free or quite cheap heating(electricity as well?) due to adjacent geothermal power.

But I guess the downside is the sulphuric rotten egg smell....and the possibility of your house falling into a geothermal vent/volcano if we get any more bloody seismic activity in our patch

[lektrode]

Re: Geothermal pluses and minuses

Steve, I read LorenS link and you have it exactly correct. It freezes ice at night and melts it during the day. Like any battery there must be losses, so it only makes economic sense if the owner can get cheaper power during off-peak.

apparently, theres a bit more to it than that, but yeah, essentially they make ice overnight, add an add'l air-to-air coil in the rooftop airhandler and then extract the 'stored cold' when the peak-rate power and higher afternoon temps make it advantageous - would expect it to require off-peak rate tariffs to make sense:
http://www.ice-energy.com/energy-sto...ompatible-hvac

ashrae_tes_final.pdf

As mentioned above, the storage section operates with
liquid overfeed. The refrigerant management system (RMS)
design effectively separates liquid and vapor, eliminating the
need to generate superheat in the storage section heat
exchanger. The entire internal surface of the ice storage heat
exchanger is wetted with liquid refrigerant, allowing utilization
of the full surface area of the heat exchanger for building
ice. The result is a heat exchanger that operates with an average
approach temperature of 5°F (2.8°C) during the charge
cycle. Minimizing the approach temperature reduces the efficiency
degradation that results from excessively low compressor
suction temperatures.
The RMS use of liquid overfeed also extends to the cooling
cycle, during which the building’s evaporator coil also
operates more efficiently, without the need for a thermostatic
expansion valve (TXV), and without any entrained oil. The
UTSS cooling cycle capacity is not a function of ambient
temperature, and this becomes an important source of efficiency
gains for the UTSS/DX system as a whole.

they talk about 'avoidance' of appx 30kwh during peak ops = suspect that its a softening of the hit on the ole demand-meter is what really makes it pay for commecial ops (a demand meter is what measures a biz's peak load and they pay LOTS for _each_ KW of peak demand: upwards of $10-19 per KW (out here), per month + the KWH charges)

By the way, have you ever wondered why your air conditioner is rated in "tons"? The very first refrigeration units were sold at the turn of the last century and purchased by people to manufacture blocks of ice delivered to home ice-boxes. Those buyers only cared about how many tons of ice they could make in a day. The engineers defined a standard thermodynamic cooling "ton" to describe that ice-freezing capacity. To this day we buy our air conditioners rated in "tons".

well... that and the fact that one ton of ice takes appx 12000 btu to melt