Yeah, yeah, I'm back one day from vacation and I have to de-lurk. Jeez.

We're having trouble in ASHRAE cultivating good preservation MEs, and it's
worse down south. There are about 4000 pages in the ASHRAE handbooks, and
the first mention of "historic buildings" appeared in the 1999 version of
Chapter 20 of the Handbook of Applications, on "Museums, Libraries and
Archive Buildings".

A year ago I reviewed an A/C design for Poplar Forest in Lynchburg VA.
They're rebuilding the home to the way it was described in Jefferson's
1820s corespondence. No pipes, no wires, no ducts, no noise. They did an
excellent job of rainwater evacuation away from the all-brick foundation,
which is the key to what follows. The board decided they wanted heat. The
preservation architect noted that the joists in the basement had had
nogging, so they decided to build a vault 400 ft from the site, install a
ground-loop heat pump, and circulate warm water through PEX piping under
the floor. That was being installed when I was there. Then the board
decided they wanted air conditioning. The architect and ME put their heads
together and came up with what I thought was an ingenious plan, with a good
chance of working. The building itself, with overhangs, shutters, opening
and closing of windows, does a good job of sensible temperature reduction.
They decided to run some fiberglass resin ducts below grade from the vault
to two hidden spots in the basement floor. Then they do some serious
dehumidification at the vault and send the air below grade into the
basement. The low dew point in the supply air keeps mold from forming in
the ducts, plus they're inspectable and cleanable. The exposed brickwork in
the basement becomes a sort of dryness sink for the house. I have no
updates, and I don't know if the system was installed for this summer. When
it is installed, or when something is installed, I know they plan to
experiment with manipulating all of the elements--windows, a fan,
dehumidification--for different weather, and rely heavily on the staff to
work the system. I'd give you the names of the the architect and the ME,
but I don't have them in the office here.

In general, step one seems to be to keep the foundation dry. Step two is
allow the indoor temperature to float upwards in warm weather--good for the
building and the artifacts, uncomfortable for regular occupants. Step 3 is
dehumidification. The only damage I've seen done by air conditioning in
historic buildings is done by the installation of air conditioning
equipment. (Mt. Vernon) There's mold that grows on overly-chilled surfaces,
but can't say I've seen that on old buildings with air conditioning.

Bill Rose
>
>Can you recommend any preservation minded HVAC contractors and engineers in
>the southeast?
>
>Also, I am looking for a project to hold up as an example of an historic
>building in the south that has delt (successfully or unseccessfully) with
>the installation of air-conditioning.
>
>Thanks for your help.
>
>John Leeke, Preservation Consultant
>
>mail: 26 Higgins St., Portland, ME, 04013, USA
>Phone: 01-207-773-2306
>email: [log in to unmask]
>website: www.HistoricHomeWorks.com
>
>