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Water Temp and Room Temp

  1. Oct 16, 2012 #1
    °Hi all,
    It has been many years since I was in school, so my phisics is very rusty.

    I have a wood boiler that was made for me, that burns my access waist wood. The boiler gets my water to 155°, and maintains it.

    I have a "kiln" room that is fully insulated, no windows, insulated doors and a heat exchanger in the room.

    I need to get the internal temperature of the wood, Oak, to 175° to ensure it is dry and down to around 6% humiditey.

    I was told that a room can get warmer then the air being pumped in. Is this corect? If it is, any idea what temp the room can get.

    If this is not correct, any idea how to calculate the water temp required to get to 175°?

    Sorry if this is a stupid question, but I can't seem to find an answer.
  2. jcsd
  3. Oct 16, 2012 #2
    First of all, wood will 'dry' below 175 degrees. At 175 degrees it would typically take some length of time; at 155 degrees, for example, it would take longer; at 120 degrees, even longer. It would even eventually dry at 32 degrees F....via evaporation of any ice....

    If your heated water is 155 degrees, no further heat transfer will occur from the hot water to the room air when the room air reaches that temperature. The air cannot become warmer than the temperature of your heat source...water,air, or whatever. So you need water at 175 degrees of higher to meet you stated objective of 175 degrees room air.
  4. Oct 17, 2012 #3


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    Not in the sense you mean. Energy naturally flows from hot to cold. So if you heated the room to say 165F using electricity and then pumped in air at 155F the air would actually cool the room.

    A heat pump is an exception. A heat pump can extract energy from air at say 50F and use it to heat a room to say 71F. However I doubt using a heat pump is economic for your application.

    If you were drying wood in a kiln using electricity on a regular basis then it might be worth recovering the waste heat from the kiln and using it to heat your house/office.
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