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Recycling Excess Heat From the Data Center

Posted by kdawson on from the talkin'-'bout-my-generation dept.

itwbennett writes "A new data center being built in Helsinki, scheduled to go live at the end of January, will generate energy and deliver hot water for the city. The data center is located in an old bomb shelter and is connected to the Helsinki public energy company's district heating system, which works by pumping boiling water through a system of pipes to households in Helsinki. The recycled heat from the data center could add about 1 percent to the total energy generated by the energy company's system in the summer." The article doesn't say what the overall efficiency of the heat recovery is. Researchers at MIT are working on a new energy-conversion technology based on quantum dots that they say has already demonstrated 40% of the Carnot efficiency limit — 4 times what is achieved by current commercial thermoelectric devices. The researchers believe they can reach 90% of the Carnot limit.

11 of 121 comments (clear)

  1. WTF, why is a Carnot reference here? by ElSupreme · · Score: 3, Insightful

    How is the Carnot cycle apply here? This is direct heat conversion, and the efficiency should be near 100%, you would have line losses.

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    1. Re:WTF, why is a Carnot reference here? by vlm · · Score: 3, Informative

      How is the Carnot cycle apply here? This is direct heat conversion, and the efficiency should be near 100%, you would have line losses.

      Reading thru a filter of journalist ignorance, I think the journalist is trying to say they're using a heat pump to reject the heat from the cooling system into the heating system's boiling water. There is a Carnot cycle limit to heat pumps.

      --
      "Science flies us to the moon. Religion flies us into buildings." - Victor Stenger
    2. Re:WTF, why is a Carnot reference here? by jank1887 · · Score: 4, Informative

      because the summary is talking about two entirely separate topics. (1) Helsinki data center will deliver waste heat in useful form to the city. (2)Researchers at MIT are working on a solid state heat-to-electric conversion element called a thermoelectric device. current devices are at best ~10% of Carnot (practical devices approach 10% total efficiency on a good day), and they say they'll hit 40-90% of carnot with their new quantum dot TEG's. We'll see.

      You are correct, though. Carnot efficiency discussion only really applies to (2) not (1). Mister itwbennett just decided to lump these two things into one submission.

  2. I think it's great, but... by natehoy · · Score: 3, Insightful

    Is pumping boiling water through pipes the most efficient way to heat houses? Isn't there a pretty massive heat loss in the pipes?

    Having said that, if they are already using this system for heat, the introduction of waste heat from a datacenter seems to make a lot of sense. Acts as a heat sink for the data center, reduces the amount of energy needed to heat the water.

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    1. Re:I think it's great, but... by onionman · · Score: 4, Informative

      Is pumping boiling water through pipes the most efficient way to heat houses? Isn't there a pretty massive heat loss in the pipes?

      Having said that, if they are already using this system for heat, the introduction of waste heat from a datacenter seems to make a lot of sense. Acts as a heat sink for the data center, reduces the amount of energy needed to heat the water.

      Actually, it's a reasonable system for heating large building complexes where a central facility can heat the water. Many Universities and large corporate complexes already use similar methods for heating their campuses. Insulation on the pipes keeps the water warm in transit. These complexes can also cool their buildings in the summer by pumping chilled water through the system.

    2. Re:I think it's great, but... by sfcat · · Score: 4, Insightful

      Yes and no, water actually is a very good "thermal" battery. That is why coastal regions have a more temperate climate than inland region. Its cheap and we know a lot about how to move it around and have existing infrastructure for doing exactly that. Its not the most efficient way, but often it is the most practical and economical.

      --
      "Those that start by burning books, will end by burning men."
  3. Valium and Xanax for Engineers and Physicists by NoYob · · Score: 5, Funny

    The pump is also very efficient -- you get five times the amount of energy you put in, he said.

    So, engineers and physicists, when you see statements like that, how do you cope:

    1. Stiff drink(s)
    2. Xanax(s)
    3. Dust off plans for your perpetual motion machine company to go public
    4. Cry yourselves to sleep.
    5. Other
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    1. Re:Valium and Xanax for Engineers and Physicists by JessGras · · Score: 5, Informative

      Heat pumps can be this efficient when you consider the claim is they can move five times as much (heat) energy as they consume (in electicity or other organized source). They are not claiming to generate more than they consume: only pump more than they consume - though vague and sensationalist phrasing in the journalism makes this unclear in the OP.

  4. That's good by Yvan256 · · Score: 5, Funny

    "Honey, why are you watching so many porn streams at once?"
    "Because I'm cold!"

  5. It IS great by dgr73 · · Score: 3, Informative

    Not to mention that when you have hot water coming out of the pipes, you don't need a water boiler, which is something all houses without kaukolämpö (remote heat) need. All in all, the infrastructure is in place in many places in Finland, with insulated pipes dug deep enough into the ground to keep the heat, so why not take advantage of it.

  6. Forced air is too dry by mi · · Score: 3, Informative

    Well, they have to be, because you're basically threading a steam bomb throughout your entire house. I'll stick with forced air thank you.

    Forced air will dry you into a raisin. It is December — do you notice, how dry your lips are in the morning?

    You need humidifiers to fight that effect... No, hot water — pumped through fixtures made of cast iron, or something, that's even slower to warm up and cool down — is the best heating solution... It could be expensive, but it is the most comfortable of what's commonly available today.

    The oft-used copper and/or aluminum fixtures are bad, because the temperature will be fluctuating widely between the times, the heat is turned on by your thermostat and the times, when it is off. Our bodies are more sensitive to changes in temperatures, than to the temperatures themselves. Also, a quickly-heating material ends up losing heat mostly through convection (heating up air, that rises to the ceiling), than through radiation, which warms you directly (via infra-red).

    Stainless steel is better in that regard than copper/aluminum, but not as good as cast iron, heavy and "unattractive" as those things might be...

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