Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Steam Networks

worksinprogress.co

Post reply on HN
Print view View original

91–100 of 161 posts

Re: Steam Networks

#91

Post by eldaisfish »

whatevaa wrote: post #80
jacobaul wrote: post #72

Earlier quoted context omitted.

Here is a great Technology Connections video which lays out why the sizing issue might not be as bad as you're thinking. The gist is that many people are steered away from heat pumps (or sold very expensive oversized units) by outdated industry thinking which vastly overestimates load calculations. I won't try to make his case here, but he is pretty convincing that a reasonably sized heat pump system can be sufficien…

It's all theoretical. In real life, retrofitting heat pumps into exisinting homes is a bit different, as those homes are neither made for air heat sources (at least in my region), nor they are insullated well. You might say, dough, insulate it, but it is easier said than done, as a lot of those old homes relied on their leakage for ventilation, not to mention that is very expensive investment (much more expensive tha…

I live in Canada in an older home with terrible insulation.

Out two tonne heat pump works just fine even at -25C this past winter.

We still have a natural gas furnace but our gas usage is down 65% despite this winter being colder than last year’s.

Tell me again how heat pumps don’t work in colder climates?

Re: Steam Networks

#92

Post by Loudergood »

whatevaa wrote: post #66
nebolo wrote: post #50

Earlier quoted context omitted.

The efficiency of modern cold-climate heat pumps plummets to 200-300% at 40F and perhaps 175% at 5F.

So at -20 and below they are basically very, very expensive resistive heaters. Good for medium climates, bad further north. Also either need very expensive oversizing or backup heat sources to compensate reduced heat output, even if you get occasional cold spikes. Unfortunately nothing in life is as simple as it first seems.

You have to go quite far north for -20F to become frequent.

Re: Steam Networks

#93

Post by bluGill »

whatevaa wrote: post #80
jacobaul wrote: post #72

Earlier quoted context omitted.

Here is a great Technology Connections video which lays out why the sizing issue might not be as bad as you're thinking. The gist is that many people are steered away from heat pumps (or sold very expensive oversized units) by outdated industry thinking which vastly overestimates load calculations. I won't try to make his case here, but he is pretty convincing that a reasonably sized heat pump system can be sufficien…

It's all theoretical. In real life, retrofitting heat pumps into exisinting homes is a bit different, as those homes are neither made for air heat sources (at least in my region), nor they are insullated well. You might say, dough, insulate it, but it is easier said than done, as a lot of those old homes relied on their leakage for ventilation, not to mention that is very expensive investment (much more expensive tha…

This is why I opposed historical designations. Most old buildings are obsolete and need to be destroyed. There are only a tiny number of buildings that are really historic, sure save them, but the vast majority are just old and need to be knocked down for something better. If it isn't taught in history class then it isn't historic.

It is easy to see the loss of something old. However the opportunity cost from not building new is something that is very hard to get people to understand.

Re: Steam Networks

#94

Post by 725686 »

Peanuts99 wrote: post #31
coryk135 wrote: post #25

This part really caught my attention: > in 1962, the anthracite seam under Centralia, PA – 25 miles to the west of Lehigh County – caught on fire and is still burning today.) That’s crazy to think that for over 60 years there’s been an underground coal mine on fire. I wonder how long the mines will burn for. The pictures on Google are quite interesting.

There's Burning Mountain in Australia which has been burning for thousands of years.

6,000 years, according to Wikipeda. That is wild.

Re: Steam Networks

#95

Post by bluGill »

Loudergood wrote: post #92
whatevaa wrote: post #66

Earlier quoted context omitted.

So at -20 and below they are basically very, very expensive resistive heaters. Good for medium climates, bad further north. Also either need very expensive oversizing or backup heat sources to compensate reduced heat output, even if you get occasional cold spikes. Unfortunately nothing in life is as simple as it first seems.

You have to go quite far north for -20F to become frequent.

If it EVER gets to -20 that is what matters. You need to prepare for the worst case weather, not the common ones.

Re: Steam Networks

#96

Post by kibwen »

blackeyeblitzar wrote: post #51

> The last total system failure was in 2007, when an 82-year-old pipe at 41st and Lexington exploded, showering Midtown in debris. Heavy rainfall had cooled the pipes, producing large amounts of condensate quickly, and a clogged steam trap meant that the system was unable to expel the water. When this build-up hit a critical level, the internal pressure shot up, causing the explosion. Almost fifty people were injured…

> I wonder how much the pent up infrastructure work to avoid these issues would cost.

The cost is essentially incalculable. Back in the 1800s people kept poor records of what they were stuffing under the streets, and the records that were kept were lost, and the ones that weren't lost are sitting in a box who knows where. NYC has effectively no idea what they're going to find under a street every time they tear one up, and the deeper you dig, the more you find.

Re: Steam Networks

#97

Post by [deleted] »

imglorp wrote: post #30

The article cites end-to-end efficiency as 60%. Plus the costs of maintaining steam generators and the pipe network. Electrical transmission systems are roughly 85% efficient to the consumer; together with boring old resistive electric radiators which are 100% efficient. So is there any reason to subscribe to the steam system for new construction?

[deleted]

Re: Steam Networks

#98

Post by bluGill »

outworlder wrote: post #57
a1371 wrote: post #52

Earlier quoted context omitted.

That's not true. Except for nuclear and solar collectors, all renewables, especially hydro, have nothing to do with steam.

What isn't true? > Most electricity is generated by using steam to turn turbines That is true. It is also true that renewables usually do not use steam. But they don't answer for "most electricity". That's natural gas, coal and other types of thermal plants, including nuclear.

Renewable power is 30% of the world grid.

Gas combined cycle power plants get part of their power from gas in the turbine directly, and part of it from steam cycles. I can't figure out what % over of power comes from which part, and not all gas power plants are combined cycled.

It seems reasonable to say that most electricity is not generated by steam turbines. However I'm not sure how to find the real data to verify this. (and pedantically the gas in a gas turbine is mostly steam)

Re: Steam Networks

#99

Post by UltraSane »

jasonthorsness wrote: post #5

Even Seattle has one of these! And the University of Washington as well. It’s amazing that the economics holds up even today. https://en.m.wikipedia.org/wiki/Seattle_Steam_Company

A LOT of universities have a central heat plant that pumps hot water to all the other buildings. I think steam has been phases out because it is so much more dangerous and electric pumps make it unnecessary.

Re: Steam Networks

#100

Post by bluGill »

perihelions wrote: post #39
imglorp wrote: post #30

The article cites end-to-end efficiency as 60%. Plus the costs of maintaining steam generators and the pipe network. Electrical transmission systems are roughly 85% efficient to the consumer; together with boring old resistive electric radiators which are 100% efficient. So is there any reason to subscribe to the steam system for new construction?

Yes: very low temperature steam is useless from a thermodynamic perspective, cannot be used to perform (meaningful amounts of) work or generate electricity. When sourced a waste byproduct of an electric power plant, it's essentially free—it has no other economic value. There's zero opportunity cost of "you could use it for some other purpose instead".

There is cost though - the pipes needed to get steam someplace are not free. Those pipes can explode when things go wrong so people can die. How you add those costs up is a debatable question, but it isn't free.
Post reply on HN