In looking for a new AC, I ran across two with the same BTUs, same
manufacturer, same energy efficiency, but the difference is that one
removes 25% more humidity per 24 hr than the other. (Basically, that
one is the new model and the other is the discontinued but-still
-available-until-sold-out version of the same AC).

How can an AC be remodeled to remove more humidity?

Sue(tm)
Lead me not into temptation... I can find it myself!

"Curly Sue" wrote in message
...
In looking for a new AC, I ran across two with the same BTUs, same
manufacturer, same energy efficiency, but the difference is that one
removes 25% more humidity per 24 hr than the other. (Basically, that
one is the new model and the other is the discontinued but-still
-available-until-sold-out version of the same AC).

How can an AC be remodeled to remove more humidity?

Sue(tm)
Lead me not into temptation... I can find it myself!

Short answer yes. I had a American Standard with a VFD on the air handler.
Startup of the compressor the fan would ramp up to 30%... stay there for a
minute. Running 5 tons of cooling through the coil and only 30 % of the air
volume it removed a lot more than a single speed unit.

Check the specs carefully if there is no other difference in the mechanical
stuff, look especially at the specs for the blower and its operation.

Might be other ways to do it I know that method works.

Larger evaporator.

--

Christopher A. Young
Learn more about Jesus
www.lds.org
www.mormons.com


"Curly Sue" wrote in message
...
In looking for a new AC, I ran across two with the same BTUs, same
manufacturer, same energy efficiency, but the difference is that one
removes 25% more humidity per 24 hr than the other. (Basically, that
one is the new model and the other is the discontinued but-still
-available-until-sold-out version of the same AC).

How can an AC be remodeled to remove more humidity?

Sue(tm)
Lead me not into temptation... I can find it myself!

Curly Sue wrote:

In looking for a new AC, I ran across two with the same BTUs, same
manufacturer, same energy efficiency, but the difference is that one
removes 25% more humidity per 24 hr than the other. (Basically, that
one is the new model and the other is the discontinued but-still
-available-until-sold-out version of the same AC).

How can an AC be remodeled to remove more humidity?

Sue(tm)
Lead me not into temptation... I can find it myself!


Sizing down Btu/hr for more runtime, --is helpful.
- udarrell

--

What is the most Affordable Path to the "Human Comfort Zone" Goal?
http://www.udarrell.com/air-conditio...tent-heat.html

Curly Sue wrote:

How can an AC be remodeled to remove more humidity?

Partially block the cool air output with some duct tape.

Nick

"Curly Sue" wrote in message
...
In looking for a new AC, I ran across two with the same BTUs, same
manufacturer, same energy efficiency, but the difference is that one
removes 25% more humidity per 24 hr than the other. (Basically, that
one is the new model and the other is the discontinued but-still
-available-until-sold-out version of the same AC).

How can an AC be remodeled to remove more humidity?

Sue(tm)
Lead me not into temptation... I can find it myself!

This is Turtle.

The one that removes more humidity has a slower speed of blower to slow the air
down just a little to make the evaperator coil colder which will make more
moisture drop out. if you want to remove a 100% more humidity with any window
unit, you just use low speed on the blower and you got a super de-humidifier.
You can just slow or speed up the fan speed on the window unit to get more
humidity out or less out.

The slower the air passes through the evaperator coils, the more humidity is
dropped out.

The faster the air passes through the evaperator coil , the less humidity is
dropped out.

TURTLE

Nick, you are so lost.
Do you mean duct tape the coil? or the duct? or the grilles? You can
use dampers in the grilles to lower air flow, but better would be to
use a dehumidistat connected to a fan speed relay to lower the blower
speed when it is humid in the house. Using duct tape to fix the
problem is a bad idea. Nick, you should change your name to MacGyver!

Stretch

Try this link to a humidity control article:


http://www.contractingbusiness.com/C...S=&NI L=false

Stretch

Stretch wrote:

Do you mean duct tape the coil? or the duct? or the grilles?

One strip perpendicular to the output grill blocking ~10% will do.

Or go buy a VFD system :-)

Nick

Stretch wrote:

Try this link to a humidity control article:

http://www.contractingbusiness.com/C...S=&NI L=false

OK. Try looking at Smart Vent's 12/19/2000 US patent no. 6,161,763
"Module-controlled building drying system and process" at
http://www.freepatentsonline.com.

It describes "...drying air circulation between inside and outside the
building based on absolute humidity and temperature sensor measurements"
and claims "a programmed controller... the input ports are connected to...
outside absolute humidity sensors... [and] inside absolute humidity sensors
[and] the output ports are connected to... [a fan system.] ...if the outside
air has a lower absolute humidity than the inside air... the fan system
output will be activated... if the outside air has a higher absolute
humidity than the inside air... the fan system will be shut down."

Nick

Hi , hope you are having a nice day

On 18-Jun-05 At About 09:49:46, wrote to All
Subject: AC humidity removal

n From:

n Stretch wrote:

n Try this link to a humidity control article:
n http://www.contractingbusiness.com/C...aw/ArticleDraw.
n aspx?CID=56 43&HBC=GlobalSearch&OAS=&NIL=fals

n Most dehumidifiers use the hot gas as condenser reheat, so they're
n self-contained and require no refrigerant piping. Therefore, they're
n easy to install... They also add some load to your air conditioning
n system, because the electricity they use shows up as heat in the
n house.

Wrong, In the basement it is cold enough that the heat doesn't really matter.
it never really warms up down there. In your world there is usually so much
that you don't take into consideration that it isn't even funny.

-= HvacTech2 =-


... "It's a small world, but I wouldn't want to have to paint it."- s.w.

___ TagDude 0.92á+[DM]
++++++++++++++++++++++++++++++++++++++++++++++++++ +++++++++++
spam protection measure, Please remove the 33 to send e-mail

Stretch wrote:

Try this link to a humidity control article:

http://www.contractingbusiness.com/C...S=&NI L=false

Most dehumidifiers use the hot gas as condenser reheat, so they're
self-contained and require no refrigerant piping. Therefore, they're
easy to install... They also add some load to your air conditioning
system, because the electricity they use shows up as heat in the house.

They forgot to mention the latent heat, about 60% more than the electrical
energy used, as I measured it.

Nick

Stretch wrote:

You can use dampers in the grilles to lower air flow...

The dampers I've seen in current window ACs only change direction.

...better would be to use a dehumidistat connected to a fan speed relay
to lower the blower speed when it is humid in the house...

Sounds good, with a $16 motor control, but the motor might hum at low speed,
and most current window ACs use a single motor with 2 fanblades, so this
would also reduce the condenser airflow.

Using duct tape to fix the problem is a bad idea.

Would you prefer an old sock? :-)

Nick

HvacTech2 wrote:

Hi , hope you are having a nice day

May you be having the finest of days as well.

n Stretch wrote:

n Try this link to a humidity control article:
n http://www.contractingbusiness.com/C...aw/ArticleDraw.
n aspx?CID=56 43&HBC=GlobalSearch&OAS=&NIL=fals

n Most dehumidifiers use the hot gas as condenser reheat, so they're
n self-contained and require no refrigerant piping. Therefore, they're
n easy to install... They also add some load to your air conditioning
n system, because the electricity they use shows up as heat in the house.

Wrong, In the basement it is cold enough that the heat doesn't really matter.

I just quoted the site, but it seems to me the quoted electrical gain is
an underestimate. If you disagree, would you have any evidence for this
peculiar article of faith? :-)

Nick

Sounds Interesting Nick. Is it actually available and how much does it
cost? Is it cheaper to operate than a dehumidifier and what is the
payback period? Due to outside RH levels here in Myrtle Beach, SC I
duobt that it would be effective here, but it may work very well in
other climates.

Stretch

Stretch wrote:

...Is it actually available and how much does it cost?

The Smart Vent? It seems to be available, at $365.

Is it cheaper to operate than a dehumidifier

Smart Vent says $8/year. BTW, all this was in my last posting.

and what is the payback period?

Compared to what?

Due to outside RH levels here in Myrtle Beach, SC I duobt that it would be
effective here, but it may work very well in other climates.

They say it works in Florida and Hawaii... NREL's Wilmington NC
weather station has these long-term averages:

Daily min/avg/max humidity ratio deep ground: 63.4 F

Apr 50.5/62.3/74.0 F 0.0080 w
May 59.3/70.1/80.8 0.0114
Jun 67.5/76.5/85.4 0.0147
Jul 71.7/80.1/88.5 0.0168
Aug 71.0/79.4/87.6 0.0167
Sep 65.3/75.3/85.2 0.0142
Oct 53.7/65.3/76.9 0.0099

Smart Vents seem very programmable. They mention 25 different control
algorithms. Ventilating with outdoor air (warmer in winter and cooler in
summer) at times when its humidity ratio is less than the hr of indoor air
seems energy-efficeint, but I suspect that can be improved, in a fairly
airtight house that can store heat and moisture.

In a house like that, with air conditioning, it seems more energy-efficient
to circulate air between the basement floor and the living space than to
exhaust basement air. Surrounded by RH% air, concrete stores about RH/20 %
moisture content by weight, with little dependence on the air temperature.

A 4"x1000ft^2 50K pound basement floor with 8K Btu/F of thermal capacitance
(or more, with no insulation below) can slowly store 500 pints of water as
the RH of the basement air rises from 40 to 60%. The ground below might have
an effective R10 thermal resistance.

If we keep a basement RH 60% all year, the moisture content of the concrete
won't change much. Maybe it's more energy-efficient to easily lower the RH
of the basement air by warming it with dry house air in wintertime to drive
moisture out of the concrete so it can absorb more moisture in summertime.

Nick

From:
To: nick pine
Sent: Monday, June 20, 2005 1:29 PM

We recently received data from an outside, independent year-long
investigation of a Smartvent equipped crawl space. Data was collected
every 4 hours.

Crawl space humidity averaged 46% for the year.

If you would like information about our new HI-IQ ventilator that
pressurizes a home or commercial building with fresh, filtered outdoor
air, let us know. This is the preferred approach throughout most of the
US. In fact, the HI-IQ is the only residential ventilation system that
measures outdoor weather. This product also uses our patented vapor
technology, outperforms ERVs HRVs and at 1/3rd the installed cost.

Used throughout the US, from Florida to Alaska, one Smartvent crawl space
ventilator usually will handle about 1800 sqft. In some cases, special
designs with extra fans are employed. In Hawaii, a 6400sqft crawl space
has additional Smartvent fans and an internal fan as well, all controlled
by one Smartvent main unit. Coastal areas usually need double capacity.

Take a look at the attachment enclosed with this email. It may shed some
light on better ventilation. Few understand the capacity of vapor
pressure based ventilation. Other foundation vents are usually closed by
hand (not sealed), and air will leak through the louvers of all your vents
when the Smartvent runs, rather than just the closest vents.

Virtually all passively ventilated crawl spaces throughout the entire US
exceed 90% RH throughout the summer, so mold and moisture damage are
serious issues.

High humidity in crawl spaces assists growth of molds, spores, and
bacteria. Under a vapor barrier, the humidity is 100%. About the only way
to keep these from migrating into the home is to cut the moisture and
ventilate, slightly depressurizing the crawl space.

Since a crawl space is never cleaned there are dead Ocritters¹, critter
droppings, etc. There may be radon or chemicals in the crawl space.
Gases from all these sources will migrate into the home unless exhausted
to the outside, replaced with fresh air.

On our web site, http://www.smartvent.netcrawlspacevent.htm if you look at
the Crawl Space Moisture Control Study, its chart on page 2, you will see
airborne water vapor is a controlling factor in crawl space humidity.
Measuring only humidity is likely to aggravate a moisture problem. The
original Smartvent that generated the information for the Crawl Space
Moisture Study produced about 90-100 cfm. The new model has been measured
at 295CFM, has upgraded software, and is considerably more effective.

To compare the Smartvent with other systems, the Smartvent is the only
system to compare inside and outside water vapor content. Some other
systems have fans on timers, some operate by measuring crawl space
humidity. Both systems are likely to make crawl space humidity worse.

Installation is fast, installing a foundation vent with clear, outdoor, 35
or 50yr caulk; looks good, cleans up easy. We provide a 6' power cord
that you plug into a 120 volt receptacle in your crawl space. That is all
the wiring you need, no remote mounting required.

Dimensions of the Smartvent are 15 1/4 x 7 7/8 x 8, just slightly smaller
than a concrete block. A Smartvent costs only about $8.00 a year to operate.

You can purchase the Smartvent directly. The Smartvent is $365. We ship
upon receipt of a check, or UPS C.O.D at $8 extra. A two year replacement
warranty is in place. For a C.O.D. shipment, email us the address, and
we likely will ship same day. Note that with a C.O.D. someone must be
there to hand UPS a check.

Larger homes can daisy chain a 2nd (or 3rd, etc.) Smartvent fan-only unit
from the first fan/controller unit. The 2nd unit is $195.

Usually we ship same or next day.

Smartvent, Inc.
3255 Cimarron Drive
Conway, AR 72032

phone 501 329 4915
fax 253 295 9111

Nick,

It may work in the winter here, but we don't need it in the winter! It
would make the house too cold inside.

We don't have basements here, most places the water table is only about
3 feet down. Basements here are called indoor swimming pools. Storing
mosture in a basement slab could encourage mold growth. How good is
your mold insurance? The device would probably work in some parts of
the USA, but not here. Nick, You should go into HVAC contracting. It
would be interesting to see if you just went broke or got sued out of
existance. But you sure keep things interesting here! :-)

Stretch

Stretch wrote:

Storing mosture in a basement slab could encourage mold growth.

Nonono. Don't deliberately store mosture. Dry out a slab in wintertime
and let it absorb mosture in summer months to avoid energy-inefficient
compressive dehumidification, in a fairly airtight house, instead of
keeping the RH constant all year. Use the mosture storage capacity of
a house for good vs evil. But as you say, this won't work everywhere.

The device would probably work in some parts of the USA, but not here.

Which device? Wilmington NC has w = 0.0048 in January and 0.0168 in July.
If we dry out a 4"x2400ft^2 slab in a house at 65 F in January, how much
mosture can the slab absorb in July before the RH hits 55% at 80 F?

It weighs about 4/12x2400x150 = 120K pounds. In 55% air, its long-term
moisture content is about 5% of 55%, ie 2.75%, so it stores 0.0275x120K
= 3300 pints of water. Air with w = 0.0048 has Pa = 29.921/(0.62198/w+1)
= 0.229 "Hg, vs 65 F air at 100% RH with Pw = e^(17.63-9621/(460+65))
= 0.630 "Hg. RH = 100Pa/Pw = 36% makes the moisture content 0.05x36%
= 1.8%, so it stores 0.018x120K = 2160 pints. The difference is 1140.

If the house begins a humid spell with a 1.8% slab moisture content and
leaks 30 cfm of outdoor air with w = 0.0168, how long before it reaches
55% at 80 F indoors, after the slab stores 1140 pints of water?

At 36% RH, 80 F air has Pa = 0.36e^(17.863-9621/(460+80)) = 0.377 "Hg and
wid = 0.612198/(29.921/w-1) = 0.00794, and 55% 80 F air has wiw = 0.0122;
wiavg = 0.0101, and the slab might absorb 24hx60x30x0.075(0.0168-0.0101)
= 21.8 lb/day of water, filling up in 1140/21.8 = 52 days, approximately.

With a more accurate differential equation, if the slab stores
P = 60C0.075(0.0168-wi) net lb/h of water and wc = 0.018+Pt/120K
and 100% 80 F air has w80 = 0.02256 and RH = 100wi/w80 = 20x100wc,
wc = 0.4513wi, so wc = 0.018+dt-cwit, where c = 5.64x10^-4 and
d = 1.89x10^-5 and d/c = 0.0372 (the equilibrium moisture content
at 80 F with w = 0.0169 and 74% RH), so wc = 0.018 +(0.018-0.0372)e^-ct
= 0.0275 after 55 days, with an RC time constant with C proportional
to the slab mass in series with R = 1/cfm.

Summer sun might keep a concrete wall or a roof or a LiCl roofpond
under a greenhouse dry...

Nick