Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
li'7l~8~
The present invention relates to a method of
heat insulating a building, particularly an industrial
building, allowing to remarkably decrease heat losses by
thermal dissipation, especially through the roof. The
invention also relates to a building with means for
carrying out the above method.
As is well known,-the heating of premises is
very expensive and the problem of reducing the relevant
costs by means of suitable measures is becoming a more and
more urgent matter.
Despite the fact that modern technology allows
the use of materials having an ever-increasing degree of
insulation, thermal dissipation or heat losses continue
to be excessively high. In particular, very high
buildings are those especially affected by heat losses
due to a concurrence of unfavourable causes.
In almost all cases, it is the lower part of
the building that is to be heated. On the other hand, in
order to keep this part at a proper temperature, it is
necessary to heat the whole of the building, and since
heat, due to a known physical effect, tends to rise, the
air temperature in upper level of a building is higher
than that at the working levelO
Furthermore, the roof is the least thermally
insulated area in industrial buildings (both for technical
and economic reasons), and it is in this area that the
greatest difference between outdoor and lndoor
temperatures occurs.
It follows that the maximum losses occur in that
part of a building where heating is not a major problem.
Moreover, the difference in temperature between the upper
and the lower parts of a building causes hot air to
escape through fissures and holes existing in the upper
part of the building, due to the so-called draught effect.
,~ ~
,~ .
''
This creates, by reaction,-corresponding filtration of a
certain amount of cold air at the lower level of the
building, where heating is most important.
In order to avoid the inconveniences mentioned
above,-the present invention provides a method of heat
insuIating buildings (industrial sheds in particular),
according to which a certain amount of air is allowed
from outside in the upper part of the shed, so as to
produce a laminar flow acting as a barrier against heat
losses due to conduction and radiation through the
building roof and walls.
The method consists substantially in allowing a
certain amount of over-pressured air to enter the upper
part of the building, and then to evenly spread it close
to the roof and walls,-so that the inner hot air does not
come into contact with the roof and walls and no loss of
heat occurs.
The admission of air such as the one described
above reduces the filtration of outside air in the lower
part of the building, permitting to recover the heat
hovering in strata in the upper part, and to utilize the
same to heat the air that was let in and that is heading
downwards.
Basically, the method consists in letting in a
certain amount of air from outside in the area of the roof,
so as to create a barrier preventing the inner hot air
from touching the roof itself and causing heat losses.
The air introduced into the room makes its way
downwards, absorbing heat from the upper hot air level,
until it reaches-the lower level at the desired temperature.
To prevent the air introduced into the room from
heading downwards following localized flow lines, there is
provided an air pervious porous barrier allowing an even
distribution of the flow over all of the surface of the
building.
~ - 2 -
li7~
Accordingly, the invention as broadly claimed
herein is a method of heat insulating a building having
a roof, comprising: blowing outside air in said
building through said roof and distributing said outside
air along said roof to create an outside air cushion
preventing warmer air in said building from reaching said
roof.
An air pervious barrier is preferably mounted
beneath the roof to define therebetween a heat insulating
zone, this barrier being suitable to allow over-
pressurization of the outside air in the zone with respect
to the pressure of the warmer air thus permitting the
outside air in the zone to move across the air pervious
barrier in the direction of the warmer air.
The invention is likewise broadly claimed
herein as a heat insulating assembly for a building
having a roof, comprising: a blower and means mounting
said blower on said roof to blow outside air into said
building, and means forcing said outside air to flow
along said roof, inside said building, to create an
outside air cushion along said roof suitable to prevent
warmer air in said building from reaching said roof.
According to a preferred embodiment, there is
provided an air pervious barrier which is mounted beneath
the roof and which defines therebetween a heat insulating
zone, which barrier is suitable to allow over-pressurization
of the outside air in the zone with respect to the pres-
sure of the warmer air thus permitting the outside air
in the zone to move across the air pervious barrier in
the direction of the warmer air.
Appended Figures 1 to 4 are schematic elevation
views of four different ways of applying the method of
the invention.
f~
-- 3 --
- `:
: :
,
11~88~s1
Fig. 1 schematically shows the section of a
building divided in two by a ceiling 1 made of a porous,
preferably translucent air pervious barrier, which
defines, below the roof,-a heat-insulating zone 2 where,
through a duct 3 and an air distribution passage 4,
there is admitted from outside an amount of air sufficient
to keep the zone 2 over-pressured as compared to the lower
warmer zone. By porous barrier~ is meant a barrier apt to
cause a loss of pressure head.
Such a pressure spreads uniformly all over the
surface of barrier 1 and, as a consequence thereof, the
flow of air passes through the ceiling 1 and heads down-
wards. The air absorbs the heat in the room, and reaches
the lower zone at the desired temperature.
By this system, therefore,-thermal insulation
of the roof is achieved, in that the higher pressure of
zone 2 prevents the heated air present in the room from
going up and reaching the roof itself.
Due to the over-pressured air present in the
room it is then possible to avoid infiltration of cold
air correspondingly at the lower part of the premises,
wherein intake openings are usually provided.
The ceiling 1 is advantageously made of trans-
lucent material, with a view to allowing the light to
pass through, in the case of sheds with overhead lighting.
Fig. 2 schematically shows the section of a
building insulated by the system according to the invention,
in the case wherein the use of the porous barrier is not
opportune or possible.
If this is the case, the outdoor air can be
admitted, e.g. by means of a fan or other known device,
through a duct 5 and a passage 6, although suitable
deflectors must be provided in order to make the air touch
the whole inner surace of the roofing.
- 4 -
- li78~
In this way the air tends to stick tangentially
to the surface, according to the Coanda principle, and a
real cold air cushion is interposed between the inside
area and the roof. In this case too the air cushion
prevents heat from reaching the roof and escaping through
it.
In Fig. 3 there is schematically shown a
building, for instance a glasshouse or the like, wherein
the ceiling 7 is built by means of a number of inflatable
tubular elements 8, preferably made of transparent
material such as, e.gO, polyethyleneO
When there is also a considerable loss of heat
through the walls, for instance in the case of glass
surfaces of large size, it is possible to apply the
porous barrier even to the walls (as illustrated, always
schematically, in fig. 4). Here a hollow space 10 is
formed in correspondence to the walls by the porous
translucent barrier 9. In this space 10, the air which
has previously been admitted in the upper part of the
building through a duct 11 and a distributing passage 12,
is appropriately distributed.
As the amount of heat which is lost through a
wall is proportional to the difference between the out-
door and the indoor temperatures,the method according to
the invention provides for the admission of a certain
- amount of air in the upper part of an industrial building,
so as to form, in correspondence to the inner surface
of the roof and walls, an air cushion preventing heat
from reaching the roof and walls.
The air is spread so as to properly insulate
the dissipative surfaces, and recover the heat existing
in strata in the upper part of the room by exploiting it
to heat the air admitted from outside.
- 5 -
~i7884~
In this manner, heat dissipation through the
roof is avoided, in that the outdoor and the indoor
temperatures (very close to the wall) are the same.
Moreover, the state of over-pressure in which
the inside of the building is kept prevents cold air from
filtering in at the lower level thereof. Because of
this, no inconvenience is caused by dust which would other-
wise occur.
The method according to the invention may be
used in various buildings, for example in glasshouses,
stables, gymnasiums, swimming-pools, meeting-rooms,
cinemas, theatres, etc. It can be applied both to roofs
and walls,-or to glass surfaces only; in the latter case,
a suitable interspace is made by means of a porous
translucent barrier.
The existing experimental uses were found to
pay off in a very short time, due to the improvements in
the environmental conditions and a considerable saving in
energy. Many changes and variations could then be
provided by a person skilled in the art, although they
should all fall within the ambit of the present invention,
as herein claimed.
. -- 6 --
