Abstrict A liquid polymer-salt solution as a desiccant in an air conditioning
system comprised of a heat-pipe having its heat absorber section
in an outside air inlet duct following water vapor adsorption into
the desiccant by a contacter section of a dehumidifier, and the
heat-pipe having its heat rejecter section in an exhaust air duct
and preferably preceeding water vapor discharge from the desiccant
by a regenerater section of the dehumidifier.
Claims I claim:
1. An air conditioning system having an outside air inlet duct,
a conditioned air supply duct into a conditioned space, a return
air duct from said conditioned space and a relief exhaust air duct
exhausting return air displaced by outside air and with a blower
means to transport said outside, supply, return and relief air,
and comprised of:
a heat-pipe having a heat absorber section in the inlet duct for
removing the heat of adsorption in the dehumidified inlet air therefrom,
and a heat rejecter section in the relief exhaust air duct for applying
heat to exhaust air flow therethrough,
and an air dehumidifier means for processing a water adsorptive
liquid desiccant and having a distribution means for wetting said
heat absorber section of the heat-pipe for interface contact of
incoming outside air with said liquid desiccant applied thereto
to adsorb water vapor therefrom and thereby defining a dehumidifier
contacter section, and having a regenerater section in the exhaust
air duct following said heat rejecter section for interface contact
of relief exhaust air with weakened liquid desiccant from said contacter
section and applied thereto by distribution means for removing the
heat of adsorption in the dehumidifier air therefrom,
and a heat source means applying heat to the regenerater section
to remove water from the liquid desiccant and into the exhaust air.
2. The air conditioning system and dehumidifier means as set forth
in claim 1 wherein the incoming outside air flows over the heat-pipe
absorber section and dehumidifier contacter section for intimate
contact with said liquid desiccant regenerated and drawn from the
regenerater section, heat of regeneration being removed by heat
exchanger means to a cold source.
3. The air conditioning system and dehumidifier means as set forth
in claim 1 wherein the regenerater section is a heat exchanger
in circuit with the heat source means and wetted with weakened water
saturated desiccant from the contacter section and through which
outgoing relief exhaust air flows for intimate contact with said
liquid desiccant to remove water therefrom by means of heat transferred
thereto by the heat exchanger.
4. The air conditioning system and dehumidifier means as set forth
in claim 1 wherein the contacter section discharges weakened water
saturated desiccant through a heat exchanger and to the distribution
means of the regenerater section, and wherein the regenerater section
discharges regenerated heated desiccant through said heat exchanger
and to the distribution means of the contacter section for heat
transfer into and for regeneration of the first mentioned weakened
desiccant.
5. The air conditioning system and dehumidifier means as set forth
in claim 1 wherein evaporative cooling means wets the rejecter
section of the heat-pipe with evaporative liquid for increasing
the cooling effect of the heat absorber section thereof.
6. The air conditioning system and dehumidifier means as set forth
in claim 1 wherein a heat exchanger in the inlet duct ahead of
the contacter section is in circuit with the heat source means to
heat incoming outside air to an optimum range of temperature for
humidification and to deter icing conditions.
7. An air conditioning system comprised of a multiplicity of independently
operable air conditioner units and each having an outside air inlet
duct, a conditioned air supply duct into a conditioned space, a
return air duct from said conditioned space and a relief exhaust
air duct exhausting return air displaced by outside air and with
a blower means to transport said outside supply, return and relief
air, and each unit including:
an air dehumidifier means for processing a water vapor adsorptive
liquid desiccant and having a contacter section in the inlet duct
for interface contact of outside air with said liquid desiccant
applied thereto by a distribution means to adsorb water vapor therefrom
and thereby weakening the desiccant,
and a heat-pipe having a heat absorber section in the inlet duct
following said contacter section for removing the heat of adsorption
in dehumified air therefrom, and a heat rejecter section in the
relief exhaust air duct,
there being a regenerater section in an outside air transfer duct
to remove said adsorbed water vapor from said weakened desiccant
from the contacter sections of the multiplicity of conditioner units
and returned thereto by said distribution means thereof,
blower means to transport said outside air through transfer duct
and through said heat transfer means therein,
and a heat source means applying heat to said heat transfer means
for said removal of said water vapor from the liquid desiccant.
8. The air conditioning system and dehumidifier means as set forth
in claim 7 wherein the multiplicity of contacter sections discharge
weakened water saturated desiccant through a heat exchanger and
to the distribution means of the regenerater unit, and wherein the
regenerater unit discharges regenerated heated desiccant through
said heat exchanger and to the distribution means of the multiplicity
of contacter sections for heat transfer into and for regeneration
of the first mentioned weakened desiccant.
9. The air conditioning system and dehumidifier means as set forth
in claim 7 wherein evaporative cooling means in at least one of
said multiplicity of air conditioner units wets the rejecter section
of the heat-pipe with evaporative liquid for increasing the cooling
effect of the heat absorber section thereof.
10. The air conditioning system and dehumidifier means as set forth
in claim 7 wherein a heat exchanger in at least one of said multiplicity
of conditioner units is in the inlet duct ahead of the contacter
section and is in circuit with the heat source means to heat incoming
outside air to an optimum range of temperature for humidification
and to deter icing conditions.
11. The air conditioning system and dehumidifier means as set forth
in claim 7 wherein the incoming outside air flows through the wetted
contacter section of each of the multiplicity of air conditioner
units for intimate contact with said liquid desiccant regenerated
and drawn from the regenerater unit, heat of regeneration being
removed by heat exchanger means to a cold source.
12. The air conditioning system and dehumidifier means as set forth
in claim 7 wherein the regenerater unit is a heat exchanger in
circuit with the heat source means and wetted with weakened water
saturated desiccant from the contacter sections of the multiplicity
of air conditioner units and through which outside air is transfered
for intimate contact with said liquid desiccant to remove water
therefrom by means of heat transferred thereto by the heat exchanger.
13. An air conditioning system comprised for at least one independently
operable air conditioner unit and each having an outside air inlet
duct, a conditioned air supply duct into a conditioned space, and
with a blower means to transport said air, and including;
an air dehumidifier means for processing a water vapor adsorptive
liquid desiccant and with a contacter section in the inlet duct
for interface contact of outside air with said liquid desiccant
applied thereto to adsorb water vapor therefrom and thereby water
saturating and weakening the desiccant,
and a heat-pipe having a heat absorber section in the inlet duct
following said contacter section for removing the heat of absorption
in dehumidified air therefrom, and a heat rejecter section in the
relief exhaust air duct,
there being a regenerater means for removing said adsorbed water
vapor from said water saturated and weakened desiccant from the
contacter section of the at least one conditioner unit and returned
thereto for water vapor adsorption thereby,
the said regenerater means being a multi stage desiccant regenerater
boiler comprised of at least two stages and each with a pressure
control means to operate at successively lower discharge of water
vapor driven out of the water saturated and weakened desiccant,
whereby desiccant returned to the at least one conditioner unit
is strengthened,
and heat source means applying heat to a first stage of the multi
stage desiccant regeneration boiler.
14. The air conditioning system and dehumidifier means as set forth
in claim 13 wherein water vapor discharge from one stage of the
boiler to a successively lower pressure stage is through a heat
recovery coil in said successively lower pressure stage and condensed
thereby.
15. The air conditioning system and dehumidifier means as set forth
in claim 13 wherein water saturated and weakened desiccant counterflows
through the stages of the multi stage desiccant regeneration boiler
from a stage of lower pressure to a stage of higher pressure.
16. The air conditioning system and dehumidifier means as set forth
in claim 13 wherein the discharge of the water vapor driven out
of the water saturated weakened desiccant is condensed and exhausted
through a heat exchanger for transfer of heat into the weakened
desiccant entering into the multi stage desiccant regeneration boiler.
17. The air conditioning system and dehumidifier means as set forth
in claim 13 wherein the discharge of strengthened desiccant from
the multi stage desiccant regeneration boiler is through a heat
exchanger for transfer of heat into the weakened desiccant entering
into the multi stage desiccant regeneration boiler.
18. The air conditioning system and dehumidifier means as set forth
in claim 13 wherein the heat source means is at a temperature to
establish a water vapor discharge pressure within a first stage
of the multi stage desiccant regeneration boiler.
Description BACKGROUND OF THE INVENTION
This invention relates to air conditioning wherein the intake of
outside air is dehumidified. Heretofore, the desiccants employed
have been expensive and because of their corrosive nature the dehumidifying
section of air conditioning equipment has been fabricated of exceedingly
expensive corrosive resistant materials, for examples calcium chloride
or lithium chloride desiccants employing copper-nickel steel equipment
is the usual requirement. Accordingly, it is a primary object of
this invention to provide a relatively inexpensive and less corrosive
desiccant, and a desiccant that is economically effective and which
is adapted to use in relatively inexpensive equipment made of commercial
grade materials such as steel that is protectively coated as by
a paint or sealant, plating, or galvanizing and the like. It is
cost effective dehumidification which is an object of this invention,
all of which is accomplished without change to the downstream refrigeration
and/or heating equipment.
There are a number of materials known to be useful as desiccants
and particularly polymers proposed to be used as solids adapted
to absorb water and to be regenerated as by drying for repeated
use. However, the use of solid desiccant involves equipment implementation
that can become bulky and oversized due to the nature of volume
increase by the cube of the structural dimensions. With solid polymer
the composition of the desiccant in a substrate is fixed. Therefore,
the water uptake is dependent only upon temperature. However, with
an aqueous polymer solution the liquid concentration can be variable,
so that the water uptake is controllable, since the vapor pressure,
concentration and temperature are all adjustable so as to maximize
their functions. It is therefore an object of this invention to
avoid objectionable size increase in the equipment by employing
liquid polymers which avoid the same as capacity requirements increase,
since they are fluid and are therefore more versatile in their applications.
Such polymers which are feasible to be used as packed desiccants
are:
Polystyrene sulfonic acids sodium salt
Polyacrylic acid ammonium salt
Poly (methacrylic acid) sodium salt
Poly (n-vinylacetamide vinyl sulfonate) sodium salt
Polyacrylic acid sodium salt
Cellulose sulfonate sodium salt
Methyl cellulose
However, it is a liquid desiccant of polymer material with which
this invention is concerned, and to this end it is an object to
provide the same in the form of hygroscopic fluids as a desiccant,
rather than in the form of solid salts.
Water vapor sorption by polymers is a recognized advantage, however
there is criticality involved in the salt to be employed therewith,
the water uptake capability being most important. The ion-dipole
interaction is therefore to be considered, reference being made
to FIGS. 3a, 3b and 3c of the drawings, which illustrate the comparisons
between the use of Lithium, Sodium and Potassium. It becomes apparent
that the Lithium ion Li+ accommodates a far greater amount of water,
of the three, due to its small cationic size as compared with either
Sodium Na+ Potassium K+. The atomic weight and corresponding cationic
size of various elements are considered, as follows:
______________________________________ Li Lithium 6.9 Na Sodium
23 K Potassium 39 Ca Calcium 40 Ca Cesium 133 ______________________________________
Therefore, it is an object of this invention to employ any one
of the known salts in the sulfonation of the aforementioned polymers
to be employed in a liquid form as a hygroscopic liquid, especially
as a desiccant. Accordingly, Polystyrene Sulfonic Acid Lithium Salt
Solution or PSSALS is a preferred embodiment herein (see FIG. 5b).
It is an object of this invention to implement the advantages of
a polymer-salt solution in dehumidification equipment, as a low
cost unit or section of equipment applicable to existant refrigeration
air conditioning equipment, without major change thereto. Air conditioning
involves generally, an outside air supply, a supply air discharge
into a building interior, return air intake from the building interior,
and a relief air discharge. The polymer-salt solution dehumidifier
of the present invention is adapted to the outside air intake and
to the relief air discharge of the existent air conditioning equipment.
It is an object of this invention to advantageously employ the outside
supply air intake temperature for desiccant treatment. It is also
an object of this invention to advantageously employ a heat-pipe
to extract heat after dehumidifier intake section herein disclosed
replaces an air intake or power section of usual equipment and is
preferably attached to a blower section unit that separates the
relief air from the return air, as shown.
An air conditioning system involves the discharge of relief air
that is replaced by outside supply air. The volume ratio of these
two columns of air varies as a result of variations in leakage from
the conditioned air spaced involved, the relief air being stale
interior air retrieved at a place or places of higher interior temperature
and where stale air exists. Consequently, relief air is substantially
warmer than supply air (the conditioned air), it being an object
of this invention to advantageously employ warmer relief air before
its discharge as exhaust air, by dissipating its usable heat energy
through the regenerater section of the dehumidifier. It is still
another object of this invention to advantageously employ the heat
energy rejected by the heat pipe, or pipes, for this purpose, as
disclosed in each of the embodiments of this invention as later
described.
In a second embodiment of this invention, FIG. 4 the adsorption
element of the dehumidifier is a heat exchanger over which the polymer-salt
solution is wetted and through which a coolant is circulated for
reduced temperature intake air into the air conditioning equipment.
In practice, the coolant is controlled and circulated by a pump,
over or through a heat exchanger, and chilled or cooled as by means
of an evaporative cooling tower (employing water). The heat-pipe
relationship remains the same as in the first embodiment.
In a third embodiment of this invention, FIG. 6 the adsorption
element of the dehumidifier is the absorber section or hot end of
the heat-pipe and over which the polymer-salt solution is wetted
for water vapor sorption and through which the heat-pipe refrigerant
recirculates for heat absorption. There is a simultaneous heating
effect and cooling effect on the outside supply air, said air being
heated as a result of the water vapor sorption by the polymer-salt
solution while being cooled as a result of heat adsorption by the
hot end of the heat-pipe. It is to be understood that the use of
a hygroscopic desiccant liquid involves regeneration through the
application of heat, which is shown herein generally as a supplemental
heat source, all according to state of the art processes. In accordance
with this invention, regeneration is by means in the discharge of
relief air over the heat rejector section or cold end of the heat-pipe.
In a fourth embodiment of this invention, FIG. 9 a central regenerater
unit services a multiplicity of dehumidifier contactor sections.
That is, a multiplicity of dehumidifier means, each serving an independent
air conditioning unit, commingles weakened desiccant to be strengthened
by a single regenerater section or unit. This combination reduces
the complexity of the dehumidifier means operable with each air
conditioner unit, and makes possible the use of a larger most efficient
regenerater unit for cost efficient operation.
In a fifth embodiment of this invention, FIG. 10 the regenerater
section is a self contained and self operable unit wherein heat
is the prime mover directly applied to the water saturated desiccant
without resort to contact with blower motivated air. Reference is
made to the polymer-salt desiccant solution disclosed herein as
the preferred hygroscopic liquid for the adsorption of water vapor.
This preferred desiccant is known to be more viscous than the usual
prior art desiccant such as Lithium Chloride, and through spray
bar distribution is practical in the contacter section of a dehumidifier
means, regeneration by means of spray bar and interface heat application
presents liquid handling problems, because of the higher viscosity.
It is an object of this invention, therefore, to directly process
the weakened higher viscosity desiccant through a multi effect boiler
concentrater, using the direct application of heat in a first high
pressure stage followed by at least one or more lower pressure stages
and with a counter flow of desiccant from which water vapor is driven
out of the weakened water saturated liquid and returned to the contacter
section or sections as strengthened desiccant.
SUMMARY OF THE INVENTION
A polymer-salt solution is provided as the desiccant in the form
of a hygroscopic liquid than can be processed and transported most
efficiently in cost effective dehumidification equipment. There
are a number of salts that may be used in the formation of the desiccant
provided, preferably one of small cationic size such as Lithium,
Sodium or Potasium. The polymer materials do not vaporize and are
reasonably stable for the purpose intended, and they are sulfonated
and retained in solution and liquid state for transport between
and effective processing at the contacter section and regenerate
section of the dehumidifier. The preferred desiccant is sulfonated
Lithium, for its small dipole configuration as illustrated in FIG.
3a of the drawings, a cost effective material that is, for example,
approximately two thirds the cost of a comparable aqueous Lithium
Chloride solution, when prepared for the purpose under consideration.
And, by employing a polymer-salt solution as specified herein, corrosive
effect upon the equipment is minimized to the extent that cost effective
materials can now be used in their construction. Accordingly, commercial
grade low cost materials can be used to replaced high grade cooper-nickel
materials.
The aforesaid employment of polymer-salt solutions for dehumidification
is advantageously combined herein with the function of heat-pipe
means, in a system that has no adverse effect on the outside air
intake to the downstream air conditioning equipment, but rather
a beneficial effect. A feature of this invention is that the dehumidified
air discharge is through heat-pipe means that removes heat added
to the outside intake air in the preceeding process of adsorption.
Another feature of this invention is the use of relief air discharge
over the heat rejecter portion of the heat-pipe means whereby heat
energy in the relief air is advantageously employed and supplemented
by a controllable heat source to operate the regenerater section
of the dehumidifier.
It is still another object of this invention to combine a dehumidifier
and a heat-pipe for simultaneous dehumidification and heat rejection
from outside intake air, ahead of refrigeration or heating by downstream
equipment. In accordance with this invention, the heat absorber
section of the heat-pipe means serves as the adsorption section
of the dehumidifier, its heat transfer surface being wetted with
the desiccant, preferably with the sulfonated Lithium solution as
described. In the summer mode of operation, outside dehumidified
air is pre-cooled. In the winter mode of operation, outside dehumidified
air is permitted to add heat through inherent reversal of the heat-pipe.
The downstream air conditioning equipment operates in either the
summer of winter mode.
The regeneration of weakened desiccant can be conducted on a unit
basis with a regenerater section assigned to each contacter section,
or on a central service basis with a common return to and supply
from a remoted regenerate unit of most efficient design. Further,
a most significant feature of this invention is the higher viscosity
of the polymer-salt solution used as the desiccant, wherein a direct
multi stage boiler regenerater section or unit is most efficient,
thereby eliminating the usual prior art liquid to air interface
contact for vaporization and water vapor discharge.
The foregoing and various other objects and features of this invention
will be apparent and fully understood from the following detailed
description of the typical preferred forms and applications thereof,
throughout which description reference is made to the accompanying
drawings.
THE DRAWINGS
FIG. 1 is a longitudinal side elevation illustrating the system
of the present invention, with the dehumidifier section installed
ahead of a downstream air conditioner.
FIG. 2 is an enlarged diagram showing a first embodiment wherein
a heat-pipe reduces outside intake air temperature and utilizes
the discharge of inside relief air.
FIGS. 3a, 3b and 3c illustrate the comparison in the cationic size
of Lithium, Sodium and Potassium ions, the preferred salts use herein
to form the polymer-salt solution as a desiccant.
FIG. 4 is a diagram similar to FIG. 2 showing a second embodiment,
wherein the adsorption section of the dehumidifier is a heat exchanger
that cools the outside intake air.
FIG. 5a and 5b are diagrams that illustrate Hydrogen and Lithium
anionic polymers, respectively.
FIG. 6 is a diagram similar to FIGS. 2 and 4 showing a third embodiment,
wherein the contacter section of the dehumidifier is combined with
the heat absorber section of the heat-pipe, and with heat rejection
into the relief air that is exhausted through the regenerator section
of the dehumifier.
FIG. 7 is a perspective fragmentary section of a heat-pipe configuration
as it is employed throughout this disclosure.
FIG. 8 is a sectional view showing the finned feature of the heat-pipe
for efficient heat transfer.
FIG. 9 illustrates a multiplicity of downstream air conditioner
units and each preceeded by a dehumidifier section, and wherein
the multiplicity of dehumidifier sections is serviced by a central
regenerater unit.
And FIG. 10 illustrates a desiccant regeneration multi stage boiler
servicing at least one or more downstream air conditioning systems
or units, and each of which has a contacter section for dehumidifying
incoming outside air.
PREFERRED EMBODIMENTS
Referring now to the drawings, FIG. 1 illustrates typical refrigeration
air conditioning equipment comprised of a power return section 10
a filter section 11 a coil section 12 a blower section 13 and
a diffuser and final filter section 14. The necessary refrigeration
compressor and condenser (not shown) are included in the coil section
12 or they are external. The power section 10 is preferably a blower
section that includes means that separates return air RA into recirculated
supply air SA which is supplemented by incoming outside air OSA
air and into relief air RE which is exhausted to outside atmosphere.
That is, a portion of the conditioned interior air is discharged
as relief air RE, and it is replaced by new incoming outside air
OSA. In practice, the discharge temperature of incoming outside
air OSA into the power return section 10 is proximate to the outside
air temperature, while the discharge temperature of relief air is
that of the warmer interior air. The sections 10-14 discharge supply
air SA into the conditioned interior at a temperature set by thermostat
control means (not shown). The downstream air conditioning equipment
is state of the art, having an intake duct at 15 to receive dehumidified
outside air, and a discharge duct 16 to deliver conditioned supply
air into a building structure. The power return section 10 is in
open communication with the intake duct 15 and receives dehumidified
outside air OAS therefrom. The power section 10 is characterized
by damper means or the like (not shown) that separates a portion
of the return air for discharge to atmosphere via a discharge duct
17 corresponding in capacity to an intake duct 18 (see FIG. 1),
ducts 17 and 18 opening at the interface of power section 10 with
the dehumidifier contactor D and regenerator section R later described. |