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Re: frugal heating this winter?? - Page 2

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Posted by News on October 8, 2004, 6:25 pm

The Barra System

This system was developed by Horazio Barra in Italy and originally used as a
passive solar heating system. Floors of reinforced concrete are used with
embedded channels utilising hollow concrete blocks. Outdoor air is blown
through the channels and when originally used the hot air emerging from the
insulated southern facing collecting wall served as thermal storage. The
system may be modified and used as a cooling system as well. At night a fan
blows ambient air through the channels and thus cold night energy will be
stored within the ceiling mass.

During the daytime the cooled ceiling will absorb the heat from the interior
space passively.

Sounds a lot like Kachadorian's Solar slab. The Kachadorian idea appears
cheap to implement, especially for a selfbuilder.

TermoDeck Passive Temperature Control Systems

The Swedish developed TermoDeck system uses the slab as both a structural
component and also a means of ducting ventilation through the building
through oval or round shaped holes within the concrete structure. Over 200
projects have been installed in Sweden and Norway and latterly Holland and

With the TermoDeck systems the slab temperature is very close to the room
temperature and makes it suitable for displacement ventilation as well as
mixed flow ventilation (see later for comparison of displacement and mixed
flow). In Summer the supply air fans at night bring in the cool air into the
hollow slabs to cool the building and the warm outside air is cooled in the

Two systems have recently been installed in the UK and the latest building
The Elizabeth Fry Building uses mechanical ventilation with heating and no
mechanical cooling at all. Mixed flow ventilation is used throughout the
building except the Lecture Theatre where displacement ventilation is used.
The building has created much interest and is being closely monitored for
energy consumption and occupant satisfaction by the PROBE team (independent
organisation monitoring buildings after occupation). The slab temperature is
kept at 22C with a deadband of 1/2C for heating and 1.5C for cooling.
TermoDeck's inventor Loa Anderson predicts with computer modelling that at
an external peak of 29C the peak internal temperature should not rise above
26C with a daily average room temperature around 22C.

The PROBE team conclude that of 12 recently constructed buildings in the UK
this building had the highest occupant comfort scores and are also recorded
the highest comfort scores recorded by the independent survey specialists
Building Use Studies. Typical energy consumption for heating and ventilation
for the UK are around 200 kWh/msq./y and for Sweden using TermoDeck between
30-50 kWh/msq./y, this building seems to be following the Swedish trend.

The TermoDeck system has since been installed in hot climates such as Saudi
Arabia where the slab tends to be kept at a temperature of 19C. The
manufacturers claim that the cooling plant capacity and associated equipment
is substantially reduced and the Elizabeth Fry research appears to confirm
significantly reduced cooling loads and running costs.
The system may be used with mixed flow or displacement ventilation, night
cooling, free cooling, desiccant cooling, packaged equipment cooling, DX
equipment, chilled water equipment and so is versatile.

As the room temperature and slab temperature are similar the room
temperature tends to be uniform and therefore assists comfort.

Termodeck appears to be a cost effective solution for commercial building,
which I'm sure the Barra System is too.

Posted by nicksanspam on October 8, 2004, 8:30 pm

In the passive version, indoor air thermosyphons through an air heater (eg
a layer of glazing over a dark wall) outside the insulated wall of a house
and rises up and flows through concrete ceiling channels from south to north,
then drops from the ceiling into the room and flows back south through the
room to the air heater inlet. The upper air heater opening might have a
passive plastic film one-way damper, or David Delaney's flow organizer. The
ceiling might have a low-e coating beneath to store more heat in warmer mass
without overheating the room. A hydronic floor above the ceiling might add
more thermal mass and control.

That won't work passively.

That won't work passively either, from the web description. It warms
outdoor vs indoor air with fossil fuels, and it doesn't use air heaters.

So the slab stores little heat.


Posted by Raleighgirl on October 9, 2004, 8:44 pm
| > >...The  key thing when trying to save on heating costs is to
| > >air leaks.
| >
| > These might be 30-50% of a typical fuel bill.
| >
| > >So our first step of which we have started again is
caulking.  We do this
| > >every year.   It gets less but we always find a few small
air leaks.
| > >Caulking is a cheap and easy DIY project that more than pays
for itself.
| >
I hate to sound ignorant, but. . .
Where do you caulk?  Around the doors and windows inside or
outside?  What do you use?  Clear caulk?  Do you paint after you
THanks for pointers.

Posted by SoCalMike on October 9, 2004, 8:56 pm
 Raleighgirl wrote:

you definitely need caulk :)

Posted by Joel M. Eichen on October 9, 2004, 9:18 pm
 On Sat, 09 Oct 2004 20:56:06 GMT, SoCalMike

Its like chewing gum ........

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