151–160 of 161 posts
Earlier quoted context omitted.
Yeah, a lot of institutions are removing steam for heating and replacing it with glycol loops.
Must be a lot lower maintenance.
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?
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?
Those electrical systems are about 85% efficient once the chemical energy in the coal has been converted to kinetic energy in the turbine. Losses in the generators themselves and in voltage loss through transformers and wires add up to about 15%. But they're only about 33% (old tech) to 45% (best-case new tech) efficient when it comes to thermal potential. Burning coal or natural gas produces lots of heat, and while…
Earlier quoted context omitted.
Those electrical systems are about 85% efficient once the chemical energy in the coal has been converted to kinetic energy in the turbine. Losses in the generators themselves and in voltage loss through transformers and wires add up to about 15%. But they're only about 33% (old tech) to 45% (best-case new tech) efficient when it comes to thermal potential. Burning coal or natural gas produces lots of heat, and while…
There's also a hybrid approach: generate electricity and also reuse heat for centralised heating. This can reach 60% efficiency as far as I remember but might require building plants closer to heat consumers.
The water isn't quite as hot as it needs to be when it arrives, so it's heated additionally in the building itself.
The article mentions a similar approach, with steam instead of water:
> They also purchase additional steam from a 322 megawatt plant in Brooklyn
Growing up in Southern California and New Mexico, the first exposure I had to systems like this was in Cities Skylines. It boggled my mind that this type of thing was still used enough to feature in a modern simulator game until I started researching them and found them to be a great solution. Very interesting article.
[1] https://www.untappedcities.com/inside-roosevelt-islands-futu...
[2] https://www.untappedcities.com/pneumatic-tube-mail-new-york-...
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That reasoning isn't enough on its own, because on the clients' end, electric heat pumps can be more efficient than direct steam heating. Actually their "efficiency" is far above 100%, https://en.wikipedia.org/wiki/Coefficient_of_performance
And their efficiency plummets starting at 40F and below.
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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.
Earlier quoted context omitted.
In terms of thermodynamics, a electric resistive heater is 100% efficient, but if the measurement is how many BTU of heating you can put into a room in a day with a certain amount of watt hours, a modern heat pump will always beat it. Also of course 100% electric.
A heat pump is more than 100% efficient on that measure. I am not sure about "always". Does it not depend on the temperature difference? The use cases for steam seem to be where you need more than room heating though: the first paragraph mentions sterilising medical equipment, humidity control, and washing.
My understanding: A heat pump is always better than resistive electric heating. Sometimes a outside air using heat pump needs to use extra energy to defrost the outside unit (with resistive electric heating). The defrosting is driven by sensors, but rarely happens more than e.g. once an hour for 5 minutes at a time. Heat pumps really do win over resistive electric heating on everything except initial cost, and that's not even hard -- resistive electric heating is very wasteful.
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.