[Greenbuilding] Fw: Biochar as Annual Cycle Building Dehumidifier

[Alan Abrams]

this may be self evident, but with regard to loading up the interior of a
building with desiccant material--let's call it hygromass--unless the
envelope and mechanical system are capable of redesiccating during dry
periods, problems can result. things can cycle from wet to dry for years
before a slowly accumulating moisture content can hit the point of
sustaining mold, so there is the potential for a stealthy failure. a WUFI
analysis, run out for, say, ten years, can predict such outcomes.

-aa

Alan Abrams

*certified professional building designer, AIBDcertified passive house
consultant, PHIUS*
*certified passive house builder, PHIUS*
cell     202-437-8583
alan at abramsdesignbuild.com
HELICON WORKS *Achitecture and Education*
<http://www.heliconworks.com/index2.html>

On Fri, Jul 3, 2015 at 1:10 PM, John Salmen <terrain at shaw.ca> wrote:

> Sorry I didn’t see the video but wouldn’t zeolites (volcanic rock
> dessicant) be more effective than any source of carbon. It is a pretty
> common dessicant and pretty cheap – works by storing water to a saturation
> or equilibrium – so when the humidity level drops the zeolite will cycle
> and release moisture to about 80% of its dry weight – so a 100 lbs will
> hold about 12 gallons of water.
>
>
>
> Not sure what kind of moisture you need to pull out but if its about 12
> gallons a day you would need about 10,000 lbs or about 7 cubic yards –
> would definitely fill a crawlspace – but then you have to draw your air
> through the crawlspace.
>
>
>
> I could imagine making an air filter using a buried concrete or poly tank.
>
>
>
>
>
>
>
>
>
> *From:* Greenbuilding [mailto:
> greenbuilding-bounces at lists.bioenergylists.org] *On Behalf Of *conservation
> architect
> *Sent:* July-03-15 7:15 AM
> *To:* Green Building
> *Subject:* Re: [Greenbuilding] Fw: Biochar as Annual Cycle Building
> Dehumidifier
>
>
>
> Many of us living on the East side of the Mississippi River, have high
> humidity in summer and low humidity in winter inside our homes when
> heated.  The relative humidity can be high in the winter outside.  However,
> by heating the cold air, it becomes very dry inside.  In the summer, the
> common practice is to cool with refrigerant driven air conditioner.  Never
> mind that all the refrigerant will leak when the seals break.  We do not
> have air conditioning.  In mountains of Virginia, we are able to keep the
> house in 70sF all summer with night flushing and closing up during the day
> with HRV running.
>
>
>
> Setting aside the issue of biochar, let me speak of increasing the
> desiccant capacity of the house similar to the what was described in video
> referenced below.  I have observed that our house has an annual cycle of
> humidity.  After heating through the winter, the house is very dry.  In the
> spring as the humidity begins to rise, past the heating season, the house
> will act as a desiccant and dehumidify  the air coming in by aDsorbing the
> humidity.  As summer and early fall, continually adds moisture, the
> capacity to aDsorb humidity out of the air becomes saturated.  By late
> summer and early fall, without active dehumidification, the house will have
> it’s highest humidity.  Then when heating season starts again, the heat
> will begin to dry out the aDsorbed humidity.  In the gradation from being
> too high, to too low RH, there will be a time where humidity released by
> drying will be a beneficial humidifying of the air, just as late spring,
> early summer the house’s dehumidifying affect is a benefit.
>
>
>
> For the past 3 years, I have been reducing the humidity in my house in the
> summer by temporarily heating to 100F+ temperature for a few hours.  Living
> near a creek may be raising my ambient humidity above normal.  However,
> when I have done that with a wood stove, I am able to cool house again by
> the following morning with RH reduced by 15%.  Because initially, my wife
> did not want me to do this, I waited until it was 90%RH in late August.
> This brought it down to a still too high, 75%RH.  On a slightly cool day, I
> got permission to do a smaller fire to get RH to 65%.  The second year, I
> pointed to the mold forming to convince here it was a problem, also in
> August.  Similar results to first year.  This year, I convinced my wife to
> proactively dehumidify by drying the house when I first saw it get to 80%RH
> temporarily.  I did this last week to get down to 64%RH.  Also, on select
> days where RH is in 50s%, I ventilate the house with fans.  I was able to
> reduce by 5% the last time this way.
>
>
>
> Now if you could increase the desiccant capacity such that describe in
> video, we can lower the peaks of dry and wet to achieve desirable levels of
> humidity without the use of refrigerants.  This assumes you can maintain a
> suitable temperature by other means.  Now if people use biochar as the
> desiccant, they can prevent the readmission of half the carbon contained in
> the wood it was created from for millennias.  In addition to sequestering
> the carbon from wood, it also reduces the carbon from manufacturing and
> running refrigerant equipment to dehumidify.
>
>
>
> This video about charcoal in Japan shows its use as an annual cycle
> dehumidifier in a home.  The relevant part of 28 minute video for this
> aspect comes at 21:28.  Any thoughts? 4,500 kilograms of charcoal were laid
> in what looked like a crawl space to absorb humidity during the summer and
> give off humidity in the winter.  Much information was not included, like
> climate, size of house, thermal envelope construction, ventilation, et.
> However, this application of a desiccant is relevant to our core subject
> of  greenbuilding.  Does anybody on list have experience using enough
> desiccant to absorb humidity in summer and release back in the winter
> inside a thermal envelope?
>
>
>
> https://www.youtube.com/watch?v=jiVmKC8xXJ8
>
>
>
> Eli
>
>
>
> *From:* Reuben Deumling <9watts at gmail.com>
>
> *Sent:* Sunday, June 28, 2015 8:59 PM
>
> *To:* Green Building <greenbuilding at lists.bioenergylists.org>
>
> *Subject:* Re: [Greenbuilding] Fw: Biochar as Annual Cycle
> BuildingDehumidifier
>
>
>
>
>
>
>
> Does anybody on list have experience using enough desiccant to absorb
> humidity in summer and release back in the winter inside a thermal
> envelope?
>
>
>
> Some of us live in climates with low humidity in the summer and very high
> humidity in the winter. I'm thinking this would not work for us, eh?
>
>
>
>
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