Posted on 02/25/2011 11:11:36 AM PST by decimon
Engineers have started drilling a hole deep below Newcastle in the search for a renewable energy source.
The Newcastle and Durham Universities team plans to sink a hole 2,000m (6,562ft) below the planned Science Central site, in the city centre.
Scientists hope the £900,000 project will result in water at a temperature of about 80C (176F) being pumped out.
The plan is the water could be used to heat the site and surrounding city centre buildings.
The project, which started on Wednesday, is expected to last six months with the team hoping to pump out the first hot water in June.
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The Newcastle project is similar to one already operating in Southampton, where underground hot water is used along with oil and natural gas for a combined heat and power network.
(Excerpt) Read more at bbc.co.uk ...
It looked like that link was for a poster showing average January air temperatures.
You’re right about ground temp being average annual ambient temp. For most of the continental US, the temperature 3 feet down and deeper, is about 50-55degrees. If you go into Mammoth Cave in KY, it’s about 54 degrees year round, if you go into Jewel Cave in SD it’s about 50 degrees year round. If you dig a 4’ deep trench and put a water pipe at the bottom and then recover it, the water in the pipe will stay about 50-55 degrees year round.
Geothermal heating systems don’t dig down to magma or whatever. They rely on the difference between air temperature (-20 to 110 degrees) and ground temperature (50-55 degrees). Most systems use a heat pump to take water from the pipes in the ground and either transfer heat into that water from the surrounding air or to use that water to heat the surrounding air. The cool thing about the heat pump is that if you have a large enough sink (i.e., a couple hundred gallons of water running through the earth outside of your house), you’re not limited to merely keeping your house at ground temperature — in the winter there is enough heat energy in the sink to keep your house pleasant. In the summer, the sink can be used to absorb and dissipate excess heat energy in your house.
The heat pump uses electricity to pump water through the system and to power an exchanger. These systems can work pretty much anywhere. In extremely cold climates where ground temperatures are low year round, the amount of electricity necessary to run a heat pump to extract useable energy in the winter would be more efficiently used in directly heating the home, so it’s not cost effective. But the system can work anywhere.
Drilling for a geothermal well is a different option that isn’t trying to use the ground passively as a heat sink.
Yes you can. We do it for oil wells even deeper sometimes. Although most geothermal units do operate as a loop, the lift can be done, but the closed loop is more energy efficient.
ESP Systems
http://www.pump-zone.com/pumps/pumps/electric-submersible-pumps-in-the-oil-and-gas-industry.html
About 15 to 20 percent of almost one million wells worldwide are pumped with some form of artificial lift employing electric submersible pumps. In addition, ESP systems are the fastest growing form of artificial lift pumping technology. They are often considered high volume and depth champions among oil field lift systems.
Found in operating environments all over the world, ESPs are very versatile. They can handle a wide range of flow rates from 70-bpd to 64,000-bpd or more and lift requirements from virtually zero to as much as 15,000-ft of lift.
That’s very interesting. Which communities? Does the hot water itself heat the buildings?
Thermal mass geo doesn’t require a hot spot or a deep well. All it needs is a stable temp at -4’ to -5’ elevation and enough room to put in a ditch 1’ wide and 80’-100’ long. It can also be done with a shallow bore hole (about 100’). It’s really amazing technology. In SE Tennessee where the soil temps are a constant 54F at -5’ you pass propylene glycol through either a coaxial absorber plate or about 300’ of coiled PEX tubing. The fluid is circulated through the field, then is then compressed twice using a heat pump, exchanging the energy pulled from the soil to freon then back to glycol for circulation in the floor. It works so well that you have to use a heat exchanger tank to keep from making steam. It’s very easy to get fluid temps in the 130F-150F range, perfect for radiant baseboard, radiant floor heat or even fan coils, although you lose a large percentage of efficiency by heating air. The run cycles of the compressors are very short, so not much electricity is used. To cool, you reverse the process using fan coil units to pull the heat out of the air through condensation. The system I’m putting in for my hangar this spring, coupled to existing LP fired radiant floor heat, runs in the neighborhood of 545% efficient for heating and 375% efficient for cooling. Pretty much blows everything else on the market away.
From the video the bore appeared to be approximately four inch, that would allow a 1½ NPS supply and return.
80-100 gpm
With a 15° drop at the exchanger and 100 gpm perhaps 7500000 btu/hr.
Service life on a typical geothermal well, about 300’ with plastic is 40 years.
One million dollars would pay for a large supply of natural gas.
Need to keep the source load high to maximize payback. An interesting project.
The Merchandise Mart Chicago second largest area next to the Pentagon uses a huge valve that only feeds steam to two opposite sections at a time. No way to actually provide heat to the whole thing at once.
Note, these are warm or hot-water geothermal sources (like the one mentioned in the article). They are very different from using geothermal wells to produce superheated steam, to generate electricity. These geothermal wells may be deep (not all are); but, they aren't more complicated than ordinary drilled-water wells. The water is just a bit warmer. OTOH, using geothermal heat to produce superheated steam is complex, and problematic in practice.
Remember, the dwarves delved too greedily and too deep.
Bingo!
Here is some info from the first image in post #18. The dimensions are reduced but the size, in bytes, is of the full image:
Size: 1,674.99 KB (1,715,185 bytes)
Dimensions: 3,300px × 2,550px (scaled to 600px × 464px)
I think we’re both talking about the same thing, namely that you need the pump operating from below (pushing the water up) rather than from above (trying to suck water up using suction)
a hole 2,000m (6,562ft)... £900,000
Hey, watch that, pallie. ;-)
Sorry, no help here. I often scale down large pictures with a link to click and see the large.
You are correct. I assumed that water was sent from the surface, heated, and returned to the surface. Since the water is already down there, then yes it must be lifted up as you said.
Use adsorption coolers 80C is plenty hot enough for LI/Br or NH3 / Carbon coolers or use a binary organic cycle using geothermal heat and run a turboexpander with the organic Rankin cycle driving a heat pump compressor directly from the turboexpanders shaft output.
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