U.S. patent number 3,867,980 [Application Number 05/311,076] was granted by the patent office on 1975-02-25 for air conditioning system.
This patent grant is currently assigned to Carrier Corporation. Invention is credited to Darwin G. Traver.
United States Patent |
3,867,980 |
Traver |
February 25, 1975 |
AIR CONDITIONING SYSTEM
Abstract
An air conditioning system including a ceiling air terminal
operable to discharge conditioned air into a room and adapted to be
connected to first and second sources of conditioned air. The first
source provides air at a temperature level which varies inversely
to changes in the outdoor air temperature. The air is discharged
from the terminal along the ceiling towards the peripheral wall of
the room to compensate for transmission gains or losses. The second
source provides air at a predetermined temperature level. The air
is discharged from the terminal along the ceiling of the room
towards the interior thereof to compensate for the remaining
cooling load therein, the volume of the air being varied in
accordance with changes in the cooling load. The volume of the
variable temperature air discharged into the room is maintained
constant irrespective of changes in the pressure of the air
supplied to the terminal.
Inventors: |
Traver; Darwin G. (DeWitt,
NY) |
Assignee: |
Carrier Corporation (Syracuse,
NY)
|
Family
ID: |
23205285 |
Appl.
No.: |
05/311,076 |
Filed: |
December 1, 1972 |
Current U.S.
Class: |
165/54; 165/59;
454/303; 236/91R |
Current CPC
Class: |
F24F
3/0444 (20130101); E04B 2009/026 (20130101) |
Current International
Class: |
F24F
3/044 (20060101); E04B 9/02 (20060101); F24f
013/06 () |
Field of
Search: |
;236/149 ;165/16,59,54
;98/4D,33A ;62/259 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Wayner; William E.
Attorney, Agent or Firm: Curtin; J. Raymond Deutsch; Barry
E.
Claims
I claim:
1. An air conditioning system for conditioning the air in a
plurality of enclosed areas in a building, each of the enclosed
areas having a peripheral portion requiring conditioned air having
a variable temperature and an interior portion requiring
conditioned air at a constant temperature, said system
comprising:
a. conditioned air supply terminal disposed in the ceiling of an
individual enclosed area;
b. first central station conditioning apparatus to provide
conditioned air at a varying temperature level;
c. means to supply said varying temperature conditioned air to a
first portion of said air terminal;
d. second central station conditioning apparatus to provide
conditioned air at a predetermined temperature level;
e. means to supply said conditioned air from said second central
station apparatus to a second portion of said air terminal, said
terminal including means to maintain the conditioned air in said
first portion separate from said conditioned air in said second
portion; and
f. said terminal further comprising discharge means, a first
section thereof being in communication with said first portion of
said terminal, said first section directing the varying temperature
conditioned air across the ceiling towards the peripheral wall of
said area, said conditioned air compensating for transmission gains
or losses caused by heat being transmitted through said peripheral
wall, a second section of said discharge means being in
communication with said second portion of said terminal to
discharge the conditioned air from said second portion across the
ceiling towards the interior portion of said area.
2. The air conditioning system in accordance with claim 1 wherein
the temperature of said varying temperature conditioned air is
maintained above the level at which transmission gains or losses
are exactly compensated for, to thereby maintain at least a minimum
flow of said second conditioned air from said second section of
said discharge means.
Description
BACKGROUND OF THE INVENTION
This invention relates to air conditioning systems for conditioning
the air in a plurality of areas or spaces in a common enclosure,
and more particularly, relates to a ceiling air terminal which is
provided for delivering the conditioned air into an individual
space.
In recent years many multi-zone buildings, such as schools,
offices, apartments, and hospitals have employed central station
air conditioning systems to provide conditioned air to regulate the
psychometric properties of the air in each of the zones of the
building. One air conditioning system that has enjoyed wide-spread
commercial success is known as a dual conduit system. A dual
conduit system is designed to supply two air streams to enclosed
areas or rooms that have a reversing transmission load; that is,
during summer, heat flows from the ambient air into the building,
whereas during winter, heat flows from the building to the ambient
air. One air stream, called the secondary air is cooled the year
round and is constant in temperature and variable in volume. The
other air stream, called the primary air, is constant in volume and
the air temperature is varied; it is warm in winter and cool in
summer. Primary air is, therefore, a constant volume-variable
temperature air stream. To obtain the two air streams, central
station apparatus are employed to provide the air temperature and
volumes required.
The primary air apparatus varies the psychometric properties of the
air supplied thereto, which may comprise a mixture of outdoor and
return air. The apparatus includes filters to remove dirt or
foreign matter entrained in the air, preheat coils as required to
temper cold winter air, a humidifier to add winter humidification
and a dehumidifier to remove excess moisture and to cool the supply
air furnished at a constant volume to the enclosed areas contained
in the building.
The secondary air apparatus also varies the psychometric properties
of the air supplied thereto and supplies either all return air, a
mixture of outdoor and return air, or all outdoor air, depending
upon the season. The apparatus contains filters to remove dirt or
foreign matter entrained in the air and a dehumidifier to remove
excess moisture and/or to cool the supply air.
A refrigeration machine is necessary to complete the overall
system. Any of the three basic refrigeration cycles, absorption,
reciprocating, or centrifugal may be considered for the
refrigeration equipment. Either chilled water from the
refrigeration machine or direct expansion of refrigerant may be
used to obtain a desired temperature for the supply air. The
foregoing system is completely described in U.S. Pat. No.
2,609,743, issued Sept. 9, 1952, in the names of Carlyle M. Ashley
and William T. McGrath.
Heretofore, it has been the practice to provide at least two
separate air discharge terminals in each of the individual enclosed
spaces. One of the terminals is connected to the source of primary
air and serves the peripheral portion of the space or room. The
other terminal is connected to the source of secondary air and
serves the interior portion of the space. The initial cost for the
air conditioning system heretofore described has thus been
relatively expensive. In addition, the terminal servicing the
peripheral portion of the room has heretofore been typically
installed under the window or adjacent to the peripheral wall, thus
generally occupying a portion of the otherwise usable floor space
of the room. Furthermore, since the peripheral terminals have been
so installed, architects have been somewhat inhibited in designing
buildings having dual conduit systems.
SUMMARY OF THE INVENTION
It is therefore an object of this invention to decrease the initial
cost of providing a dual conduit system.
It is a further object of this invention to utilize a single
ceiling air discharge terminal to provide conditioned primary and
secondary air into each of the enclosed spaces.
It is yet another object of the present invention to provide a
ceiling air terminal which effectively discharges primary air to
either heat or cool the peripheral portion of an enclosed space,
and in addition effectively discharges secondary air to cool the
interior portion of the enclosed space.
These and other objects of the present invention are obtained by
providing a dual conduit air conditioning system. The system
includes a source of primary air and a source of secondary air. The
source of primary air is connected by suitable conduit means to a
first portion of a plenum which is provided in the ceiling of the
space being conditioned. The source of secondary air is provided by
suitable means to a second portion of the plenum. The primary air
is maintained separate from the secondary air.
Diffuser means are operably connected to the plenum for discharging
the primary air and secondary air streams into the space. The
diffuser means discharge the primary air from the air terminal so
that it is directed towards the peripheral wall of the space and
flows along the ceiling thereto. The diffuser means further
operates to discharge the secondary air along the ceiling of the
space so that it is directed towards the interior portion thereof.
First regulating means are operably connected to the diffuser means
to maintain the discharge of primary air at a substantially
constant volume irrespective of changes in the pressure in the
first portion of the plenum. Additionally, second regulating means
are associated with the diffuser means to vary the discharge of
secondary air into the space in accordance with the changes of the
cooling load therein.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 of the drawing illustrates a typical space in a building
wherein the air terminal of the present air conditioning system may
be employed;
FIG. 2 schematically illustrates the air conditioning system in
accordance with the present invention; and
FIG. 3 illustrates a sectional view of a ceiling air terminal
suitable for use in the air conditioning system of the present
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings, and in particular to FIG. 1 thereof,
there is shown an enclosed space 18, which may be a room or area in
an office building or similar structure. Room 18 includes a
peripheral wall 20' having window 20 therein. The room further
includes a ceiling 19. Typically, in the modern office building,
ceiling 19 comprises a plurality of acoustical tiles 19' which are
suspended from the actual ceiling, the acoustical tiles defining a
"false" ceiling.
A ceiling air terminal 21 is disposed in the space between the
false ceiling and the actual ceiling. Ceiling air terminal 21 is
operable to discharge conditioned air in a manner that shall be
more fully explained hereinafter to condition room 18 to a desired
temperature and humidity level.
Referring now to FIG. 2 there is shown an air conditioning system
including terminal 21 in accordance with the present invention. The
air conditioning system 10, which may be described as a central
station type, includes an air conditioning equipment section
designated generally by the numeral 12, and a conduit system 14,
15, for conducting conditioned primary and secondary air,
respectively, to each of the areas or rooms 18 of the building
served by the air conditioning system. Equipment section 12 may be
in a basement or on the roof of the building.
For the purpose of this description, primary air may comprise fresh
air or ventilating air drawn from the outdoors, or a mixture of
outdoor air and return air treated in section 12, while secondary
air may comprise return air from the areas being conditioned and
treated in section 12. The apparatus for conditioning the primary
air preferably includes a filter 24 to remove foreign matter
entrained in the air, heating or reheating coil 26 to elevate the
temperature of the air flowing in the primary air system or circuit
and a cooling or dehumidifying coil 25 to remove excess moisture
and to cool the supply air as required, arranged in series flow
relationship and encased within a suitable housing 28. The passage
of primary air over coils 25 and 26 is regulated by dampers 59 and
60.
The portion of such central station equipment regulating the
secondary air preferably includes a suitable filter 30 to remove
foreign matter entrained in the air and a dehumidifier or cooling
coil 31 to remove the excess moisture and/or cool the supply air,
arranged in series flow relationship and encased within a suitable
housing 32. Chilled water is supplied to coils 25 and 31 via
suitable means (not shown).
Housings 28 and 32 are connected by duct 33 with return air exhaust
fan 34. The inlet of fan 34 is connected with return air plenum 40,
which is connected by suitable means (not shown) with the areas or
enclosed rooms 18 being served by air conditioning system 10.
Preferably, inlet air control vanes 35 are provided to vary the
flow of air through fan 34. Adjustable dampers 36 are provided to
vary the flow of return air to the primary air conditioning
apparatus. Exhaust dampers 37 connect duct 33 with the outdoors.
Dampers 37 control the volume of return air discharged to the
atmosphere. Housing 28 connects with primary air fan 38. Conduit
means 14 conveys primary air from fan 38 to the areas or rooms 18
being conditioned. Housing 32 is connected to the outlet of return
air fan 34. Preferably adjustable dampers 45 are provided to vary
the flow of supply air to the secondary air conditioning apparatus.
Adjustable dampers 46 are provided to regulate the flow of outdoor
air to the secondary air conditioning apparatus. Conduit means 15
conveys air from fan 47 to the area or rooms being conditioned.
Conduit means 14 and 15 provide the primary air and secondary air
to each ceiling air terminal 21; a single air terminal being
disposed in each of the rooms 18.
With reference to FIG. 1 it is clearly observed that ceiling air
terminal 21 is disposed relatively close to peripheral wall 20' of
room 18. Conduit means 14 is connected to a first portion 61 of
plenum 63 of the terminal. Conduit means 15 is connected to a
second portion 62 of plenum 63. Thus, primary air, whose
temperature may be varied in accordance with changes in temperature
of the ambient air outside the enclosure, is discharged from plenum
portion 61 through diffuser section 64 of the unit and flows along
the ceiling 19 towards peripheral wall 20'. The discharged air then
flows along the wall 20' to thus blanket window 20 and wall 20'
with a layer of conditioned air. The temperature of the air will
compensate for transmission gains or losses that will occur as a
result of conduction through the peripheral wall, and in particular
through the window of the room.
Furthermore, it has been determined that air discharged from the
unit will establish an air circulation pattern that will prevent
any cold air flowing into the room and not neutralized by the
temperature of the primary air, from creating undesirable down
drafts. Such cold air will be recirculated in the air current
created by the flow of primary air across the ceiling.
The secondary air will be discharged from plenum 62 via diffuser
means 65 which will direct the air along the ceiling towards the
interior portion of room 18. As noted before, the temperature of
the secondary air is maintained relatively constant. Suitable means
(not shown) will sense the temperature of the room and will vary
the quantity of air discharged from the unit to maintain the
temperature in the room at a predetermined level.
A baffle or partition member 66 divides plenum 63 into first and
second portions 61 and 62 and thus maintains primary air separate
from secondary air so that there is no intermixing
therebetween.
With reference to FIG. 3, there is shown a ceiling air terminal of
a design suitable for use in the air conditioning system of the
present invention. Such ceiling air terminal is operable to cause
the air discharged therefrom to flow along the ceiling of the
room.
Plenum 63 is ordinarily lined with a sound absorbing material 67,
such as a glass fiber blanket. An air supply distribution plate 68
having a plurality of collared openings 69 therein is provided to
evenly distribute the supply air from plenum 63 into distribution
chamber 70 which is defined by the top and side walls of
distribution plate 68. To provide an optimum room air discharge
pattern, the air supplied to the distribution chamber from the
plenum should have minimal non-vertical velocity components. Since
the air supplied to the ceiling terminal is ordinarily introduced
horizontally into the end of the terminal, there is a large
horizontal velocity component to the air stream within the plenum.
The distribution plate employing a large number of collared
openings is very effective in providing an efficient, nonturbulent
vertical diversion of the air stream from plenum 63 into
distribution chamber 70. This minimizes noise generation within the
terminal. The collars divert the horizontal velocity component of
the air stream so that the velocity components of the stream within
distribution chamber 70 are vertical.
The bottom of distribution chamber 70 includes aligned cutoff
plates 71 which are provided with a curved surface 72 for
engagement by bladders 73 and 74 to form a damper. The curved
surfaces smooth the flow of air through the damper to minimize the
pressure drop therethrough when the bladder is fully deflated and
provide a lower noise level over the entire operating range of the
terminal as bladder inflation is varied between a fully deflated
position and a fully inflated position. Surface 72 is covered with
felt 75 to further minimize noise.
By varying the inflation of the bladders, the area of the openings
between the bladders and the cutoff plates may be varied. This
feature can be utilized to provide a variety of modes of terminal
operation. As noted before, it is desired to maintain a
substantially constant discharge of primary air from the terminal,
regardless of changes in the static pressure of the air in plenum
portion 61, to compensate for transmission gains or losses. A
suitable pressure responsive control may be employed to inflate
bladder 73, in response to supply air pressure to reduce the area
between the bladder and cutoff plate as duct pressure increases and
to increase the area therebetween as duct pressure decreases. It
should be noted that, as used herein, the term "substantially
constant" includes decreasing the flow of primary air by a minimal
amount to partially compensate for variations in the internal
cooling or heating load of the room. The minimal decrease in flow
may be obtained by varying the inflation of bladder 73 in response
to changes in temperature in the room as sensed by a suitable
thermostat.
As noted before, it is desirable to control discharge of air from
plenum portion 62 to provide a constant room temperature under
varying cooling loads. The inflation of bladder 74 is thereby
selectively controlled by a thermostat responsive to room
temperature to provide an increased quantity of air flow from
plenum portion 65 as the cooling load increases and a decreased
quantity of air flow from the plenum portion as the cooling load
decreases.
Bladders 73 and 74 are adhesively mounted on a central partition
assembly comprised of opposed generally convex plates 76 and a
diffuser triangle 77. The plates have a V-shaped recessed area so
the bladders are completely recessed within the plate when
deflated. This provides a large area between the active walls of
the bladders and the cutoff plates for maximum air flow
therebetween. Further, the recessed bladder provides a smooth
surface along plate 76 to minimize air turbulence.
By reference to the drawings, it may be seen that the walls of the
bladders are concave. When bladders 73 and 74 are fully deflated,
the active walls thereof are out of the air stream to minimize the
possibility of bladder flutter. By recessing the bladder within the
plate 76 and providing the bladder with the concave wall, the
distance between the cutoff plate and the wall of the bladder is
increased. This provides a greater opening between the bladder and
the cutoff plate when the bladder is fully deflated for maximum air
flow therebetween. Further, a large movement of the wall from a
concave to convex position may be obtained without stretching the
bladder material.
The damper mechanism is disposed a substantial distance upstream
from the discharge openings in the terminal to provide sufficient
space therebetween to absorb any noise generated by the damper
mechanism. For maximum sound absorption, downwardly extending walls
78 which form air passages in conjunction with plates 76, are lined
with sound absorbing material such as a glass fiber blanket 79.
Outlet members 80 having outwardly flared portions 81 are fixed, as
by welding, to walls 78.
The convex plates prevent direct, straight line passage of sound
energy waves from the damper into the area being conditioned. The
sound waves generated at the damper strike sound absorbing blankets
79 where they are absorbed, to prevent passage of noise from the
terminal. The upper portion of the passageway formed between plate
76 and walls 78 has a constantly decreasing cross-sectional area in
the direction of air flow and the lower portion of the passageway
has a constantly increasing cross-sectional area in the direction
of air flow. The change in the cross-sectional area of the
passageway, in conjunction with the sound absorbing blanket, aids
in the dissipation of sound energy which may be generated upstream
of the passageway.
The ceiling air terminal hereinabove described is particularly
suitable to discharge the primary air in the manner required to
compensate for transmission gains or losses. In addition, the
terminal discharges the secondary air, and in combination with a
thermostat regulates the flow thereof to compensate for changes in
the internal cooling load. For a more detailed explanation of the
air terminal, reference may be made to U.S. Pat. No. 3,554,111,
issued Jan. 12, 1971, Darwin G. Traver and Fred V. Honnold, Jr.,
inventors. Other terminals that operate to discharge the
conditioned air therefrom so that the air will flow along the
ceiling of the room may be employed without departing from the
spirit of the invention.
Heretofore, if it has been desired to install an air conditioning
system of the type disclosed herein, it has been necessary to
provide two separate air terminals. In particular, it has been
thought that, the primary air terminal should be placed below the
window or on the floor adjacent to the peripheral wall, otherwise
proper conditioning would not be obtained in the room or space.
Applicant has determined a ceiling air terminal may be employed
satisfactorily to compensate for both transmission gains or losses
and to compensate for variations in the internal cooling load. An
air conditioning system including the ceiling air terminal as
disclosed hereinabove reduces the installation cost of a dual
conduit system without reducing the operating efficiency
thereof.
It has been found that, in order to insure proper air circulation
within the entire space, the primary air should be supplied at a
temperature slightly above the level at which total compensation
for transmission gains or losses will be accomplished. This will
insure that at least a minimum flow of secondary air will be
discharged from the terminal to obtain adequate circulation in the
entire room.
While a preferred embodiment of the invention has been described
and illustrated, the invention should not be limited thereto but
may be otherwise embodied within the scope of the following
claims.
* * * * *