Energy efficient basement dehumidification?

[eeinpa]

Hello! Please pardon my ignorance in advance... I'm an EE, and my only thermo course remotely related to HVAC was at 8am 4 days a week

With increasing energy costs, I'm trying to greatly limit the amount of energy I use. My largest use of electricity this time of year comes when I turn on my basement dehumidifier (standalone unit--no central AC in house). My basement isn't WET, but it is damp, and the unit runs almost non-stop much of the time to keep it from becoming musty.

I was wondering if anyone has experimented with clever ways to ventilate a space such as this to try to control humidity without resorting to mechanical refrigeration? For example, could one use small ventilating fans with temperature and humidity sensors and a logic controller, taking advantage of swings in outside air temperature and humidity to decrease RH in a basement?

This may seem crazy to some people, but I believe it may take some crazy ideas to adapt our country to coming increases in energy costs!

I'd be quite interested in hearing from anyone who has done this or is trying to. I have industrial controls experience and could potential implement control strategies for someone who has the HVAC theory, but not the electronics background.

Thanks!

 

[DonPhillips]

I suggest you try to slow the water infiltration. Depending on the age of the house, you probably do not have footing drains, nor foundation waterproofing, and the grade arond the foundation probably has settled. Unless you have water coming up the slab, a good investment would be to excavate around the perimeter, install a footing drain, waterproof the foundation, and backfill with gravel around the drain and perhaps 2' to 4' up. May sure your finished grade slopes away at least 6" in 10' from the foundation, and the downspouts from the gutters are clear and freeflowing.

An added benefit to all this is reduced hydrostatic pressure on the wall, and of course, less water in the air and a reduced need for dehumidication. If the basement ever gets finish, it would reduce the likelihood of mold growth behind the finishes.



Don Phillips

http://worthingtonengineering.com

 

[KiwiMace]

In addition to Don's first step - Moisture that finds it's way in, needs an exit strategy. Given that your house is unconditioned, and you probably have all the windows open upstairs anyway, adding 4-6 air changes of ventilation will likely be more efficient than your mech dehumidification.

 

[cry22]

Now if you are at the bottom of the hill like I am in a 1958 house. your problem may be subterranean water from uphill.
I Had the dump smell when I moved in 8 years ago, I decided to finish the basement and install a sump pump with indoor footing drain all around the basement (the sump pump was more fore water filtration after a snow storm).
I installed insulation, vapor barrier, dry wall, etc.
I di have air conditioning. But the problem disapeared after I was dine with basement finish job.
now was it the insulation and vapor barrier or the sump pump, or a combination of both that got rid of the dump smell I cannot tell. The bottom line, the smell is long gone.
I do agree with Don above, I was recommended that approach by several peoples, but I decided to go for for the expensive way.

 

[eeinpa]

Thanks for the replies so far.

I appreciate that Don's solution is probably "the right" solution. But in classic modern American style, I'd rather address the symptoms, not the disease!

Seriously, what he proposes is beyond my resources. The house incorporates a porch, large deck, and patio as well as concrete and flagstone sidewalks and landscaping which interfere with access to the foundation. I could rent an excavator and expose the foundation if I could get to it, but I really can't without greatly impacting the property. If I were going to stay here another 10 years, it might be worth the investment, but I don't intend to.

As for trying to provide more air changes... great! But how do I do it? Should I install a turbine vent on the roof? A powered blower? Where should I bring in air, ground level or up high? Should I use a humidistat to turn off the ventilation when the outside RH is higher than inside? What type of inlet device to I use to exclude foreign objects? I've never seen an installation like this, so I have no idea what's available! There is no central air, so currently no provision at all to actively bring in outside air. Since the basement has only 3 newer windows, there isn't much leakage down there, either.

Thanks for additional suggestions!

 

[AbbyNormal]

get a humidifier with more than 40 pint per day capacity then like a thermastor santa fe or an aprilaire 1700

Take the "V" out of HVAC and you are left with a HAC(k) job.

 

[eeinpa]

Does the dehumidification capacity really have an effect on energy usage? I would think a large dehumidifier running part of the day would NOT be more efficient than a smaller dehumidifier running much of the time. In fact, intuitively I would suspect the converse, much as a diesel engine running at a steady load near its rated capacity is most efficient.

 

[AbbyNormal]

you mentioned the basement was still damp, so perhaps the 40 pinter is not enough

The ventialtion scheme will only work on cooler days or the winter. The sell junk for those schemes called a Humidex

Take the "V" out of HVAC and you are left with a HAC(k) job.