U.S. patent application number 12/581806 was filed with the patent office on 2011-04-21 for energy recovery ventilator and dehumidifier.
Invention is credited to Kenneth W. Kayser.
Application Number | 20110088417 12/581806 |
Document ID | / |
Family ID | 43878246 |
Filed Date | 2011-04-21 |
United States Patent
Application |
20110088417 |
Kind Code |
A1 |
Kayser; Kenneth W. |
April 21, 2011 |
Energy Recovery Ventilator And Dehumidifier
Abstract
An energy recovery ventilator system includes a belt partially
located in each of a first chamber and a second chamber. First and
second desiccant units are positioned on the belt. At least some of
the first desiccant units are in the first chamber at a first
relative humidity, causing air received in the first chamber to
achieve a first air humidity. At least some of the second desiccant
units are in the second chamber at a second relative humidity, the
second relative humidity being caused by the air received in the
first chamber. The second relative humidity is modified to the
first relative humidity by air passing through the second chamber,
the air achieving a second air humidity. A controller causes the
belt to move second desiccant units from the second chamber to the
first chamber when the first air humidity fails to comply with a
specific air humidity.
Inventors: |
Kayser; Kenneth W.;
(Catawba, VA) |
Family ID: |
43878246 |
Appl. No.: |
12/581806 |
Filed: |
October 19, 2009 |
Current U.S.
Class: |
62/94 ; 62/176.1;
62/271 |
Current CPC
Class: |
F24F 2012/007 20130101;
Y02B 30/56 20130101; F24F 2203/1044 20130101; F24F 12/001 20130101;
Y02B 30/563 20130101; F24F 3/1423 20130101; B01D 53/261
20130101 |
Class at
Publication: |
62/94 ; 62/176.1;
62/271 |
International
Class: |
F25B 49/00 20060101
F25B049/00; F25D 23/00 20060101 F25D023/00 |
Claims
1. An energy recovery ventilator system comprising: a first chamber
and a second chamber; a moving belt having a first portion
positioned in the first chamber and a second portion positioned in
the second chamber; a plurality of desiccant units positioned on
the moving belt, the desiccant units including a plurality of first
desiccant units and a plurality of second desiccant units, each of
the desiccant units being in a saturated stated, the first
desiccant units being located in the first chamber at a first
relative humidity and causing air received in the first chamber to
achieve a first air humidity, and the second desiccant units being
located in the second chamber at a second relative humidity, the
second relative humidity being caused by the air received in the
first chamber, the second desiccant units being modified back to
the first relative humidity by air passing through the second
chamber, the air passing through the second chamber achieving a
second air humidity; and a controller communicatively coupled to
the moving belt and operable to cause movement of the moving belt,
the controller causing the moving belt to move at least some of the
second desiccant units from the second chamber to the first chamber
when the first air humidity fails to comply with a predetermined
air humidity.
2. The energy recovery ventilator system of claim 1, wherein a gap
is formed along an adjacent boundary between the first chamber and
the second chamber, the moving belt including a plurality of
separators positioned at predetermined intervals on the moving
belt, at least one of the separators being positioned in the gap to
seal the first chamber from the second chamber and prevent
cross-contamination between air in the first chamber and air in the
second chamber.
3. The energy recovery ventilator system of claim 1, wherein the
plurality of desiccant units are packets of silica gel.
4. The energy recovery ventilator system of claim 1, wherein the
first chamber operates in a dehumidifier mode in which moisture is
removed from the air in the first chamber by passing through the
first desiccant units, the second chamber operating in an energy
recovery mode in which moisture is added to the air passing through
the second chamber by passing through the second desiccant
units.
5. The energy recovery ventilator system of claim 1, wherein the
first chamber operates in a dehumidifier mode during a first time
period and in a reverse mode during a second time period.
6. The energy recovery ventilator system of claim 1, wherein, in an
energy recovery mode, the air passing through the second chamber is
expelled to the external environment.
7. The energy ventilator system of claim 1, further comprising a
plurality of sensors, including humidity and temperature sensors, a
position sensor, and a temperature sensor, a first one of the
humidity and temperature sensors being positioned near the first
chamber; a second one of the humidity and temperature sensors being
positioned near the second chamber; a third one of the humidity and
temperature sensors being positioned near an outlet duct of a heat
exchanger that is located adjacent to the first chamber and the
second chamber; and a fourth one of the humidity and temperature
sensors being positioned near an inlet duct of the heat exchanger;
wherein the position sensor is located in the second chamber near
the moving belt and the temperature sensor is located in the second
chamber.
8. The energy ventilator system of claim 1, wherein the controller
is coupled to a position sensor, the controller determining whether
a gap between the first chamber and the second chamber is properly
sealed based on positioning input received from a position sensor
located near the moving belt.
9. The energy ventilator system of claim 1, further comprising a
heat exchanger including a plurality of layers, each of the layers
having two plates separated by a plurality of separator
segments.
10. The energy ventilator system of claim 9, wherein the plurality
of separator segments include one or more foam tape segments or
molded tape segments.
11. The energy ventilator system of claim 9, wherein at least one
of the plates is an aluminum plate having at least one deformation
formed on a plate surface for deflecting flow of air in the heat
exchanger to create a turbulent air flow.
12. The energy ventilator system of claim 11, wherein the at least
one deformation is selected from a group consisting of a protrusion
deformation and an embossment deformation.
13. The energy ventilator system of claim 9, wherein at least one
of the plates has an array of deformations formed on a plate
surface, the array causing a turbulent air flow in the heat
exchanger.
14. A method for recovering energy in a ventilator system, the
method comprising: receiving fresh air from an external environment
into a dehumidifier chamber; adsorbing moisture from the fresh air
to a plurality of first desiccant units to lower the humidity of
the fresh air, the first desiccant units being in a saturated state
at a first relative humidity; sending dehumidified air into a room
environment; receiving room air from the room environment into an
energy recovery chamber; removing moisture from the room air to a
plurality of second desiccant units, the second desiccant units
being in a saturated state at a second relative humidity, the
removing of the moisture causing the saturated state at the second
relative humidity of the second desiccant units to change to the
saturated state at the first relative humidity; and in response to
determining that relative humidity of fresh air is higher than a
predetermined humidity, replacing at least one of the first
desiccant units from the dehumidifier chamber with a corresponding
one of the second desiccant units from the energy recovery
chamber.
15. The method of claim 14, further comprising expelling the room
air to the external environment after passing through the energy
recovery chamber.
16. The method of claim 14, further comprising sealing gaps formed
between the dehumidifier chamber and the energy recovery chamber
with separators formed in a rotating belt.
17. The method of claim 14, further comprising passing the
dehumidified air through layers of a heat exchanger, the layers
being formed by two adjacent plates separated by tape segments.
18. The method of claim 17, further comprising creating a turbulent
air flow by passing the dehumidified air passed an array of
deformations formed on a surface of at least one of the plates.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to an energy
recovery system, and, more particularly, to an energy recovery
ventilator and dehumidifier having a desiccant in a saturated
equilibrium state.
SUMMARY OF THE INVENTION
[0002] According to one aspect, an energy recovery ventilator
system includes a first chamber and a second chamber. A moving belt
has a first portion positioned in the first chamber and a second
portion positioned in the second chamber. A plurality of desiccant
units are positioned on the moving belt, the plurality of desiccant
units including a plurality of first desiccant units and a
plurality of second desiccant units, each of the desiccant units
being in a saturated stated. The first desiccant units are located
in the first chamber at a first relative humidity for causing air
received in the first chamber to achieve a first air humidity. The
second desiccant units are located in the second chamber at a
second relative humidity, the second relative humidity being caused
by the air received in the first chamber. The second desiccant
units are modified back to the first relative humidity by air
passing through the second chamber, the air passing through the
second chamber achieving a second air humidity. A controller is
communicatively coupled to the moving belt and is operable to cause
movement of the moving belt. Specifically, the controller causes
the moving belt to move at least some of the second desiccant units
from the second chamber to the first chamber when the first air
humidity fails to comply with a predetermined air humidity.
[0003] According to another aspect, a method for recovering energy
in a ventilator system is directed to receiving fresh air from an
external environment into a dehumidifier chamber. Moisture is
adsorbed from the fresh air to a plurality of first desiccant units
to lower the humidity of the fresh air, the first desiccant units
being in a saturated state at a first relative humidity.
Dehumidified air is sent into a room environment, and room air is
received from the room environment into an energy recovery chamber.
Moisture is removed from the room air to a plurality of second
desiccant units, the second desiccant units being in a saturated
state at a second relative humidity. The removal of the moisture
causes the saturated state at the second relative humidity of the
second desiccant units to change to the saturated state at the
first relative humidity. In response to determining that relative
humidity of fresh air is higher than a predetermined humidity, at
least one of the first desiccant units from the dehumidifier
chamber is replaced with a corresponding one of the second
desiccant units from the energy recovery chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] The invention may best be understood by reference to the
following description taken in conjunction with the accompanying
drawings, in which:
[0005] FIG. 1 is a diagrammatic of an energy recovery ventilator
system, according to one embodiment.
[0006] FIG. 2 is a chart illustrating adsorbent capacities of
Silica Gel.
[0007] FIG. 3 is an illustration of the energy recovery ventilator
system in an energy recovery ventilator (ERV) and regeneration
mode.
[0008] FIG. 4 is an illustration of the energy recovery ventilator
system in a dehumidifier mode.
[0009] FIG. 5 is an illustration showing sensors of the energy
recovery ventilator system
[0010] FIG. 6 is a perspective view of a heat exchanger and duct
system, according to an alternative embodiment.
[0011] FIG. 7 is a side view illustration of the heat
exchanger.
[0012] FIG. 8 is a perspective exploded view of the heat
exchanger.
[0013] FIG. 9 is a top view illustration of a partial layer of the
heat exchanger having a plurality of air-diverting deformations,
according to one embodiment.
[0014] FIG. 10 is a top view illustration of a partial layer of the
heat exchanger having an array of air-diverting deformations,
according to an alternative embodiment.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
[0015] Although the invention will be described in connection with
certain preferred embodiments, it will be understood that the
invention is not limited to those particular embodiments. On the
contrary, the invention is intended to cover all alternatives,
modifications, and equivalent arrangements as may be included
within the spirit and scope of the invention as defined by the
appended claims.
[0016] Referring to FIG. 1, an energy recovery ventilator ("ERV")
system 100 includes an air inlet 102 through which, typically,
fresh air enters the ERV system 100. The ERV system 100 is useful
in stabilizing humidity year-round, including during the winter and
the summer, and has a theoretical efficiency near 100%. As
explained in more detail in reference to FIGS. 3 and 4, the ERV
system can be operated at least in an ERV mode and a dehumidifier
mode. A first motor control damper 104 (e.g., a fresh air damper)
is positioned generally proximate to the fresh air inlet 102. The
fresh air passes through a first filter 108 into a dehumidifying
chamber 110 in which a desiccant belt 112 is located, in part. The
desiccant belt 112 includes a plurality of separators 114, between
which desiccant units 116 (e.g., silica gel packets) are
located.
[0017] In the dehumidifying chamber 110, the fresh air is modified
to achieve a desired humidity. The modified fresh air exits the
dehumidifying chamber 110 at relative humidity through a first heat
source 118, past a first fan 120 (which drives the flow of air) and
a second filter 122, into a counterflow heat exchanger 124 to
achieve a desired temperature. From the heat exchanger 124, the
modified fresh air exits via an outlet duct 126, typically, into a
room that is being cooled.
[0018] On an exhaust path, room air enters an inlet duct 128 of the
heat exchanger 124 and passes through a third filter 130, a second
fan 132 (which drives the flow of air), and a second heat source
134, into a regeneration chamber 136. The room air, as explained in
more detail below, is useful for regenerating the desiccant units
116 on the desiccant belt 112, which is movable between the
dehumidifying chamber 110 and the regeneration chamber 136.
[0019] A motor 137 is operated to move the desiccant belt 112
between the two chambers 110, 136. If the ERV system 100 is not in
a dehumidifier mode (which is described in more detail below in
reference to FIG. 3), the room air exits the ERV system 100 via an
air outlet 138. The second motor control damper 106 (which
functions as a bypass damper) is operable to divert the air flow
between the desiccant belt 112, in the dehumidifying chamber 110,
and a bypass duct 140. An anti-back flow flap 142 is operated
between an open position (as illustrated) and a closed position
(illustrated in FIG. 4) to control air flow towards the air outlet
138.
[0020] Referring to FIG. 2, a chart illustrates adsorbent
properties of various desiccants in relation to a Silica Gel
material, which, in contrast to other materials, has a generally
linear capacity versus relative humidity in the range of 20-80%.
For example, the Silica Gel can adsorb 10 kilograms of water (per
100 kilograms of Silica Gel) at about 20% relative humidity, and
about 30 kilograms of water (per 100 kilograms of Silica Gel) at
about 60% relative humidity. Thus, the adsorbent capacity of Silica
Gel increases, generally linearly, with the relative humidity at a
rate of about 1 kilogram of water for about 2% increase in relative
humidity.
[0021] For the ERV system 100 of the present application, a
material exhibiting properties similar to the Silica Gel is
preferred because such a material provides good adsorbent capacity,
adsorbing sufficient water from the passing air, and because such a
material can properly achieve a desired relative humidity based on
the linear adsorbent capacity relative to the relative
humidity.
[0022] Referring to FIG. 3, the ERV system 100 is illustrated in
the ERV mode in which fresh air is regulated to a desired humidity,
via the dehumidifying chamber 110, and a desired temperature, via
the heat exchanger 124. Then, the regulated air is exhausted to a
room environment through the outlet duct 126. When passing through
the dehumidifying chamber 110, the air passes through the desiccant
units 116 so that undesired air moisture is absorbed before the air
exits to the heat exchanger 124. The first control damper 104 is in
an open position, to allow exterior air to come in the ERV system
100, and the second control damper 106 is in a closed position to
divert the air into the dehumidifying chamber 110. The first fan
120 is operated to pull the air through the dehumidifying chamber
110, into the heat exchanger 124.
[0023] On the return path, air from the room environment enters the
inlet duct 128 and is pulled by the second fan 132 through the heat
exchanger 124 into the regeneration chamber 136. The second control
damper 106 is in the closed position to ensure that the air passes
through the regeneration chamber 136, and does not flow through the
bypass duct 140. From the regeneration chamber 136, the air exits
through the air outlet 138 to the exterior environment.
[0024] In the regeneration chamber 136, the desiccant belt 112
includes desiccant units 116 that require regeneration. After
adsorbing moisture from the air in the dehumidifying chamber 110,
the desiccant units 116 reach a state in which they become
saturated at a higher humidity level and, as such, the desiccant
units 116 are no longer removing the desired humidity from the air.
When this state is reached, the desiccant belt 112 is rotated to
move the desiccant units 116 from the dehumidifying chamber 110 to
the regeneration chamber 136. In the regeneration chamber 136,
heated and dry air that is expelled from the room environment is
utilized to regenerate (or dry) the desiccant units 116. In other
words, the relative humidity of the desiccant units 116 is reduced
in the regeneration chamber 136. Moisture from the desiccant units
116 (which are now in the regeneration chamber 136) is removed by
the passing heated and dry air, which would otherwise be expelled
directly towards the air outlet 138 (to the outside, external,
environment).
[0025] The desiccant belt 112 is rotated to maintain the desiccant
units 116 in a saturated equilibrium state to maintain a specific
relative humidity. The desiccant belt 112 includes a sufficient
volume of desiccant units 116 to achieve the desired relative
humidity. According to one embodiment, the volume of desiccant
units 116 is high enough to prevent continuous movement of the
desiccant belt 112. In other words, the volume of desiccant units
116 is high enough to permit a stationary time period of the
desiccant 112, before rejuvenation of the desiccant units 116 is
necessary.
[0026] Referring to FIG. 4, the ERV system 100 is illustrated in
the dehumidifier mode, in which air from the room environment is
dehumidified in the dehumidifier chamber 110. In the dehumidifier
mode, the first control damper 104 is in the closed position to
prevent fresh air from entering the ERV system 100, and the
anti-back flow flap 142 is also in the closed position to prevent
air expelled from the room environment to exit the ERV system 100
via the air outlet 138. The second control damper 106 is in the
open position to allow the air expelled from the room environment
to bypass the regeneration chamber 136 via the bypass duct 140.
From the bypass duct 140, the air is recirculated to the
dehumidifier chamber 110 by moving the second control damper 106 in
the open position. In the dehumidifier chamber 110, air from the
room environment is regulated to the desired humidity and, then, to
the desired temperature in the heat exchanger 124, after which it
is passed back toward the room environment.
[0027] The second heat source 134 can be a thermal mass that is
used to capture the heat of condensation transferred to the
incoming air stream in the heat exchanger 124. After a sufficient
amount of heat is captured by the thermal mass, the ERV system 100
switches temporarily to the ERV mode to regenerate the desiccant
units 116. In another embodiment, the heat source 134 can be a
condenser coil located in the high pressure/hot area of an
associated air conditioner unit for using waste heat from the air
conditioner unit to regenerate the desiccant when the ERV system
100 is in the dehumidifier mode. Thus, the dehumidifier mode
recirculates air to/from the room environment such that the only
actions are to regulate the air temperature and humidity in the
dehumidifying chamber 110. In comparison, the ERV mode circulates
air to/from the external environment such that the air temperature
and humidity is regulated in the dehumidifying chamber 110 and
desiccant units 116 are regenerated in the regeneration chamber
136.
[0028] Referring to FIG. 5, the ERV system 100 is illustrated with
a plurality of sensors, including humidity and temperature (HT)
sensors 144a-144d, a position (P) sensor 146, and a temperature (T)
sensor 148. The humidity and temperature sensors 144a-144d include
a first sensor 144a near the dehumidifier chamber 110, a second
sensor 144b in the regeneration chamber 136, a third sensor 144c in
the outlet duct 126, and a fourth sensor 144d in the inlet duct
128.
[0029] The sensors are communicatively coupled to a central
processing unit ("CPU") 150, which has an optional antenna 152 for
receiving/sending communications. This communication channel can be
used, for example, for reporting operational parameters,
maintenance status, and operating system upgrades. A power supply
154 provides the required electrical power to operate the ERV
system 100. The CPU 150 causes the desiccant belt 112 to move
intermittently when a determination is made that the air in the ERV
system 100 has degraded to an undesired temperature and/or
humidity. The humidity and temperature (HT) sensors 144a-144d
provide input to the CPU 150 to determine the amount of energy that
has to be recovered. Accordingly, when the energy being recovered
is lower than a predetermined energy value, the desiccant belt 112
is moved.
[0030] The position sensor 146 senses the position of the desiccant
belt 112 to identify movement of the separators 114, as they move
between the dehumidifier chamber 110 and the regeneration chamber
136. Two separators of the separators 114, such as a first
separator 114a and a second separator 114b, are always positioned
in an area between the dehumidifier chamber 110 and the
regeneration chamber 136 to seal the two chambers from each other
and, consequently, to prevent cross-contamination between air
flowing through respective chambers.
[0031] In reference to FIGS. 1-5, the ERV system 100 has been
described as both an ERV system and a dehumidifier typically as
used during the warm and humid months of the year (e.g., summer
season). However, the ERV system 100 can also be used during the
cold and dry months of the year (e.g., winter seasons), but in
reverse. For example, reversing the process, moist desiccant units
116 that require regeneration are now in the dehumidifying chamber
110 and dry regenerated desiccant units 116 are now in the
regeneration chamber 136. As such, cold dry air from the external
environment passes through the moist desiccant units 116 positioned
in the dehumidifying chamber 110, and is humidified in the process.
In the return path, hot humid air from the room environment passes
through the dry desiccant units 116 in the regeneration chamber
136, filling the dry desiccant units 116 with moisture to be used
(after the desiccant belt 112 is rotated) in the humidifying
chamber 136.
[0032] Referring to FIG. 6, a counterflow heat exchanger 600 has a
plurality of layers 602 through which air flows between an external
environment and a room environment. Fresh air is directed to the
heat exchanger 600 through a first inlet portion 604, from the
external environment, and exits through a first outlet portion 606,
to the room environment. Room air is directed to the heat exchanger
600 through a second inlet portion 608 from the room environment,
and exits through a second outlet portion 610.
[0033] Referring to FIG. 7, the heat exchanger 600 further includes
a plurality of plates 612 separated by a plurality of separator
segments 614 (also referred to as tape segments). The plates 612
can be made from any desirable material, such as foam tape (e.g.,
open foam tape) or molded tape, and can have a relatively small
thickness, such as a 10 thousandths of an inch thickness. The
separator segments 614 are, in general, attached around the
periphery of the plates 612 or in an internal area between the
plates 612. The heat exchanger 600 further includes a plurality of
deformations 616 that are formed on the surface of the plates
612.
[0034] Referring to FIG. 8, some separator segments 614a, 614b are
oriented across respective ones of the plates 612 to direct air
flow in a particular pattern. The deformations 616 are positioned
on each layer 602 in a desired pattern to create a respective air
flow within the heat exchanger 600. The orientation of the
deformations 616 is dependent on the direction of the air flow. For
example, the orientation of deformations 616 on a first layer 602a,
through which air may flow from the external environment to the
room environment, can be directly opposite to the orientation of
the deformations 616 on a second layer 602b, through which air may
flow from the room environment to the external environment.
[0035] The deformations 616 are positioned such that turbulent air
flow is achieved in the heat exchanger 600. The deformations 616
can include protruding deformations and/or embossing deformations.
Protruding deformations are deformations raised above a thickness
plane of the plate 602 (as illustrated in FIG. 8), and embossing
deformations are deformations punched below the thickness plane of
the pate 602 (not shown). Although the deformations 616 are shown
to have a triangular shape, the deformations 616 can have other
shapes.
[0036] Referring to FIGS. 9 and 10, the deformations 616 can be
positioned and oriented in various ways. For example, as
illustrated in FIG. 9, only a small number of deformations 616 can
be positioned on the plate 612, each of the deformations 616 being
oriented in the same direction on the plate 612. In another
example, illustrated in FIG. 10, a large number of deformations 616
can be positioned on the plate 612, each of the deformations 616
having a different orientation than at least some of the other
deformations 616.
[0037] The heat exchanger 600 may be considered to be a disposable
heat exchanger because it consists primarily of elements (e.g.,
plates 612 and separator segments 614) that are relatively
inexpensive and easy to manufacture. For example, the cost of one
embodiment of the disclosed heat exchanger 600 may be about $50, in
contrast to some present heat exchanger that may cost thousands of
dollars. Another advantageous aspect of having the separator
segments 114 is that they act as a muffler to reduce noise entering
the building.
[0038] While particular embodiments and applications of the present
invention have been illustrated and described, it is to be
understood that the invention is not limited to the precise
construction and compositions disclosed herein and that various
modifications, changes, and variations may be apparent from the
foregoing descriptions without departing from the spirit and scope
of the invention as defined in the appended claims.
* * * * *