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rmay635703 11-18-2015 01:11 PM

Just for thought, but why?
 
Capturing and Distributing Waste Heat From Power Generation | GreenBuildingAdvisor.com

I have long wondered why powerplants don't distribute hot water to surrounding houses and businesses.

And yes I am aware of the 1% in New York and Philly but lets ignore that for a moment.

In Weston WI, there are 4 coal fired plants, the general rule of thumb is if it can provide electricity for a house, that same energy can also heat the same house, meaning the power plant throws away about half its energy (at best)

Any thoughts why large scale co-generation is so unpopular?

ksa8907 11-18-2015 03:32 PM

I can think of one really big reason. Liability

jamesqf 11-18-2015 07:01 PM

One reason is that, at least hereabouts, thermal (fossil fuel and nuclear) power plants tend to be located quite a long ways - hundreds of miles, sometimes - from any significant number of houses.

Fat Charlie 11-18-2015 08:37 PM

Our society's record of maintaining and protecting infrastructure doesn't inspire much confidence in a widespread network of hot water pipes.

me and my metro 11-18-2015 09:10 PM

I work for a major power company. Many of our power plants have installed secondary heat recovery generators to use the cooler discharge water. They really are trying to be efficient.

niky 11-18-2015 11:45 PM

Quote:

Originally Posted by me and my metro (Post 499819)
I work for a major power company. Many of our power plants have installed secondary heat recovery generators to use the cooler discharge water. They really are trying to be efficient.

Makes sense. If you can sell the heat, stands to reason you can also use it in-house.

SDMCF 11-19-2015 02:13 AM

It can be done, if there is the will to do it. CHP is very common in this part of the world. As of 2011 (the latest detailed figures I have seen) there were 169 towns in Finland with district heating networks, totalling 13100 km of district heating pipelines. (Source)

An example I have visited is Naantali, where district heating production for 2011 was 1 315.6 GWh of which losses were 2.4 GWh. Not bad losses considering their output includes steam delivered to industry some of which is over 10 km away and some of the heat distribution network is above ground in a harsh climate and some, if I remember correctly, is even under the sea.

Another nice example is in Stockholm where they have a district heating network and also the world's largest district cooling network. So they can extract heat from places that need to be cooled or refrigerated and move it to places that need to be heated. Now that is cool, if you will pardon the pun.

rmay635703 11-19-2015 09:36 AM

Quote:

Originally Posted by jamesqf (Post 499806)
One reason is that, at least hereabouts, thermal (fossil fuel and nuclear) power plants tend to be located quite a long ways - hundreds of miles, sometimes - from any significant number of houses.

Weston 1-4 are located within 5 miles of 10,000 dwellings

jamesqf 11-19-2015 02:03 PM

Quote:

Originally Posted by rmay635703 (Post 499849)
Weston 1-4 are located within 5 miles of 10,000 dwellings

Well, that's not "hereabouts" for me. The local utility's fossil plants are located roughly 20-200 miles from large numbers of houses. And that's straight-line distance: there are a number of mountain ranges &c between.

I think it comes down to economics. How much would it cost to build a network of distribution pipes? And you'd have to have a return system too, since you wouldn't want to just dump the water in a sewer (in most places, which are rather drier than Wisconsin). Then you have to figure the cost of pumping water through the system...

There are better ways to use the waste heat. Secondary recovery is one, of course, but there are others. Back when I worked for the power company (a couple of decades ago) they used the heat for dehydrating potatos, looked at raising tilapia fish in the cooling ponds, and a number of other uses I don't recall offhand. There was even a guy who wanted to start an alligator farm, though I don't think it ever got off the ground.

rmay635703 11-19-2015 03:20 PM

Quote:

Originally Posted by jamesqf (Post 499879)
Well, that's not "hereabouts" for me.

I think it comes down to economics. How much would it cost to build a network of distribution pipes?

I don't know but we are constantly building systems that include 2 water pipes coupled with 1 "gas" pipe all underground to every house in our area.

One could assume the mission critical gas pipe would be omitted on homes with the extra pipe and it would be a differential of how much the cost difference is between a gas pipe that can't leak and a water pipe that has to be insulated.

Another more radical thought, why not just use the existing pipes, the powerplant complex makes enough heat to heat 500,000 homes, more than are even in the area, why not just run all municipal water as hot through existing lines, the heat sync affect would eventually allow the water to be hot in most areas and to get cold water you would need a heat sync.

user removed 11-19-2015 03:26 PM

Think of the old triple and quadruple expansion steam engines, generate more electricity and use the existing distribution system. Any decent potential heat differential will get you there. Vary the working fluids as pressures drop. Running the next engine off this engines exhaust steam.

regards
mech

jamesqf 11-19-2015 11:55 PM

Quote:

Originally Posted by rmay635703 (Post 499882)
I don't know but we are constantly building systems that include 2 water pipes coupled with 1 "gas" pipe all underground to every house in our area.

Constantly building? To every house? No, most houses are already built, with the supply lines installed decades ago. (Thus amortizing the cost over those decades.) Much more disruptive & expensive to dig up roads & landscaping to retrofit.

Quote:

One could assume the mission critical gas pipe would be omitted...
Still used for cooking.

Quote:

Another more radical thought, why not just use the existing pipes, the powerplant complex makes enough heat to heat 500,000 homes, more than are even in the area, why not just run all municipal water as hot through existing lines, the heat sync affect would eventually allow the water to be hot in most areas and to get cold water you would need a heat sync.
Because in most cases the powerplants are not located anywhere near the water sources? Because the energy & equipment needed to cool water would wipe out most of the hypothetical savings?

rmay635703 11-20-2015 10:04 AM

Quote:

Originally Posted by jamesqf (Post 499927)
Constantly building? To every house? No, most houses are already built, with the supply lines installed decades ago. (Thus amortizing the cost over those decades.) Much more disruptive & expensive to dig up roads & landscaping to retrofit.

Most of the new construction in our area is by the powerplant, most of our houses have been getting sewer water recently.

The water treatment plant and pump facilities are also right next to the powerplant as are a variety of businesses including a shopping mall and cheese factory that could use waste heat.

Just seems so foolish that the waste heat does nothing but make steam on the road and keep the river clear

jamesqf 11-20-2015 12:51 PM

Quote:

Originally Posted by rmay635703 (Post 499950)
Most of the new construction in our area is by the powerplant...

OK, that's you. I imagine this isn't the case, most places. So you don't have e.g. economies of scale in producing the equipment, or architects & construction workers who know how best to install it. Same basic problem as solar space heat & hot water, which is an even better alternative in many places.

Also, what happens to all those water-heated houses in 20 years or so, when emissions regulations, increasing cost of fossil fuel, and decreasing cost of solar/wind/whatever make the plant uneconomic to run?

Xist 11-20-2015 01:58 PM

Obviously, you would still need water heaters, in case the water happened to not be hot enough, and then you would have hot water heaters! :eek:

freebeard 11-20-2015 07:37 PM

People don't set their standards high enough. A properly designed and constructed home (well insulated, with very high-tech glazing and an air-to-air heat exchanger) would be homeostatic (I made a pun!) and need power only for localized heat/cold shunting. And the grow lights.

Fat Charlie 11-20-2015 08:13 PM

The problems there are payback time and the market.

The housing market values square feet, number of bathrooms, bedrooms and garages. I've never seen a real estate listing that even mentioned insulation or furnace type (unless it was to mention radiant in the floors of a room or two). It's hard for them to factor in the value of reduced heating costs in the price of the house.

Payback time hurts at construction time, just like with solar. Building in a lifetime of reduced heating and cooling expenses costs a lot right now, while the benefits trickle in very slowly, if they can ever be quantified directly. Banks don't like financing extra insulation costs because when the house gets sold, it still comes back to just how many bedrooms you've got.

When I'm rich and famous I'll have a passive house. Solar and ****. Until then I'm stuck in a regular house and I try to be efficient in it.

Fat Charlie 11-20-2015 08:14 PM

Oops. I just got automatically censored. $#*+.

cRiPpLe_rOoStEr 11-20-2015 09:02 PM

If I had a genset at home I'd try co-generation.

freebeard 11-21-2015 04:08 AM

Quote:

Building in a lifetime of reduced heating and cooling expenses costs a lot right now, while the benefits trickle in very slowly, if they can ever be quantified directly.
I lived for a number of years in a geodesic dome. It was the cleanest, warmest and quietest place I've ever lived—all qualities due to it's hemispherical shape. Dust only settles in corners, toroidal air circulation conserves heat and the shape dissipates exterior sounds. A streamlined exterior shell and solar and wind powered operation don't have to cost more up front.

I'm stuck too. It's 256sq ft which is nice, but it's a long skinny rectangle instead of a circle.


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