U.S. patent application number 09/888204 was filed with the patent office on 2002-12-19 for smart air cleaning system and method thereof.
This patent application is currently assigned to Honeywell International, Inc.. Invention is credited to Arnold, Karin, Michalakos, Peter, Tom, Robert.
Application Number | 20020193064 09/888204 |
Document ID | / |
Family ID | 25392737 |
Filed Date | 2002-12-19 |
United States Patent
Application |
20020193064 |
Kind Code |
A1 |
Michalakos, Peter ; et
al. |
December 19, 2002 |
SMART AIR CLEANING SYSTEM AND METHOD THEREOF
Abstract
An air cleaning system and method employs both particulate and
gaseous contaminant removal from a flowing air stream to improve
air quality in a selected environmental space. Particulate
contaminants are removed by an appropriate filter. Gaseous
contaminants such as VOCs, CO, and O.sub.3 are removed using a
catalyst to oxidize such contaminants. The air stream is
selectively heated to provide an adequate catalyst reaction
temperature and the heat energy is then recovered by a heat
exchanger. Various sensors are employed to monitor flow rate, air
composition, temperature and pressure. A controller is programmable
to control air quality for either minimizing contaminants or
minimizing energy usage required to achieve a selected minimum air
quality over a period of time.
Inventors: |
Michalakos, Peter; (Chicago,
IL) ; Tom, Robert; (Redondo Beach, CA) ;
Arnold, Karin; (Toronto, CA) |
Correspondence
Address: |
Honeywell International, Inc.
Law Dept. AB2
P.O. Box 2245
Morristown
NJ
07962-9806
US
|
Assignee: |
Honeywell International,
Inc.
Morristown
NJ
|
Family ID: |
25392737 |
Appl. No.: |
09/888204 |
Filed: |
June 19, 2001 |
Current U.S.
Class: |
454/257 |
Current CPC
Class: |
F24F 8/167 20210101;
B01D 53/8696 20130101; F24F 11/30 20180101; F24F 3/16 20130101;
F24F 2110/00 20180101; B01D 53/8675 20130101; B01D 53/8668
20130101; B01D 53/8643 20130101; F24F 8/98 20210101 |
Class at
Publication: |
454/257 |
International
Class: |
A62C 002/06 |
Claims
1. An air cleaning system for reducing air contaminants within a
selected interior volume, the system comprising: at least one
catalyst device for oxidizing gaseous contaminants in said interior
volume; a plurality of sensors for determining selected
characteristics of air of said interior volume; said plurality of
sensors having at least one temperature sensor for measuring the
temperature of said air of said interior volume within said
cleaning system; and a heater for raising the temperature of said
interior volume air within said cleaning system for enabling
reaction of said gaseous contaminants with said at least one
catalyst device, said heater being controlled in accordance with
the measurement of temperature by said at least one temperature
sensor.
2. The air cleaning system recited in claim 1 wherein at least one
of said plurality of sensors is a composition sensor.
3. The air cleaning system recited in claim 1 wherein at least one
of said plurality of sensors is a pressure sensor.
4. The air cleaning system recited in claim 1 wherein at least one
of said plurality of sensors is a flow rate sensor.
5. The air cleaning system recited in claim 1 further comprising a
blower for increasing flow rate of an air stream through said air
cleaning system; and wherein at least one of said plurality of
sensors is a flow sensor.
6. The air cleaning system recited in claim 1 further comprising at
least one filter for removing particulate contaminants from air
within said interior volume.
7. The air cleaning system recited in claim 1 further comprising an
adsorbent device for removing by-products of said at least one
catalyst device.
8. The air cleaning system recited in claim 1 further comprising a
heat exchanger for recovering heat from air in said system heated
by said heater and output from said at least one catalyst
device.
9. The air cleaning system recited in claim 5 further comprising a
controller unit receiving signals from said plurality of sensors
and controlling said heater in accordance with the output of said
at least one temperature sensor and controlling said blower in
accordance with the output of said at least one flow sensor.
10. The air cleaning system recited in claim 9, said controller
having a user input setting control for permitting an occupant to
select a parameter relating to the degree of air contaminant
reduction in said air cleaning system.
11. The air cleaning system recited in claim 10, said controller
having an additional input based upon the occupancy level of said
interior volume.
12. The air cleaning system recited in claim 9, said controller
system having a programmable processor for controlling said air
cleaning system in a selected variable manner over a period of
time.
13. An air cleaning system for use in a substantially enclosed
environmental space for reducing air contaminants within the space,
such contaminants including particulate and gaseous contaminants;
the system comprising: a blower forming an air stream through the
system; a filter for removing said particulate contaminants from
said air stream; a heater for raising the temperature of said air
stream; a catalyst device for oxidizing said gaseous contaminants
in said heated air stream; and a heat exchanger for recovering heat
energy from said heated air stream output from said catalyst
device.
14. The air cleaning system recited in claim 13, further comprising
a pair of pressure sensors, one such pressure sensor upstream of
said filter and one said pressure sensor downstream of said filter
for determining air stream pressure drop through said air
filter.
15. The air cleaning system recited in claim 13, further comprising
at least one composition sensor for determining the amount of
selected contaminants in said air stream.
16. The air cleaning system recited in claim 13, further comprising
at least one temperature sensor for determining the temperature of
said air stream.
17. The air cleaning system recited in claim 13, further comprising
a flow rate sensor for determining the rate of said air stream
flow.
18. The air cleaning system recited in claim 13, further comprising
an adsorbent device for removing by-products of said catalyst
device from said air stream.
19. The air cleaning system recited in claim 15, further comprising
a controller unit receiving an output of said at least one
temperature sensor and controlling said heater in accordance with
said output, and receiving an output of said at least one flow
sensor and controlling said blower in accordance with said
output.
20. The air cleaning system recited in claim 19, wherein said
controller has a user input setting control for permitting an
occupant to select a parameter relating to the degree of air
contaminant reduction in said air cleaning system.
21. The air cleaning system recited in claim 20, wherein said
controller has an additional input based upon the occupancy level
of said interior volume.
22. The air cleaning system recited in claim 19, wherein said
controller has a programmable processor for controlling said air
cleaning system in a selected variable manner over a period of
time.
23. An apparatus for reducing particulate and gaseous contaminants
in a substantially enclosed environment, the apparatus comprising:
a blower creating a stream of air through said apparatus; a
particulate filter for removing said particulate contaminants in
said stream; a pair of pressure sensors, one said pressure sensor
located adjacent said filter upstream and one said pressure sensor
located adjacent said filter downstream for measuring the pressure
differential through said filter; a series of sensors for measuring
temperature, composition and flow rate of said stream downstream of
said filter; a heat exchanger located downstream of said series of
sensors; a heater located downstream of said heat exchanger for
selectively heating said stream of air; at least one catalyst
device for oxidizing at least one said gaseous contaminants in said
air stream, said heater raising the temperature of said stream to
cause an oxidizing reaction in said catalyst device; an adsorbent
device located downstream of said at least one catalyst device for
removing by-products of said reaction from said stream; the stream
emanating from said adsorbent device being returned to said heat
exchanger to transfer heat energy from said emanating stream to
said stream of air upstream of said heater; and a controller
receiving signals from said series of sensors and responsively
controlling said blower and said heater to achieve a desired
reduction of said contaminants within said enclosed
environment.
24. A method for reducing air contaminants in a substantially
enclosed environmental space; the method comprising the steps of:
a) providing an air stream; b) passing said air stream through a
heater and measuring the temperature of the air stream emanating
from said heater; c) oxidizing gaseous contaminants in said air
stream by reacting such contaminants in a catalyst; and d)
recovering heat energy from said air stream by passing said air
stream through a heat exchanger.
25. The method recited in claim 24, further comprising the step of:
e) passing said air stream through a particulate filter to remove
particulate contaminants from said air stream.
26. The method recited in claim 24, further comprising the step of:
e) controlling the flow rate of said air stream and the temperature
of said heater to improve the air quality of said environmental
space according to a selected program.
27. The method recited in claim 24, further comprising the step of:
e) adsorbing by-products of the oxidizing step c).
28. The method recited in claim 24, further comprising the step of:
e) sensing the level of contaminants in said air stream and
controlling said heater and the flow rate of said air stream to
reduce said level.
29. The method recited in claim 26 wherein step e) is carried out
based upon known data regarding oxidizing efficiency of said
catalyst with variable air stream temperature and flow rate.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to air treatment systems and,
more particularly, to a "smart" air cleaning system such as for
volatile organic compounds and carbon monoxide that may exist in a
variety of environments.
[0002] There is substantial public and government concern over
contaminated air in commercial and residential buildings because of
the impact on health and safety, odors, and comfort. This is
especially true of modern "tight" buildings where the outside
ventilation rates are low to reduce air-conditioning and heating
costs, and also in locations where the outdoor air itself is
contaminated. Most air treatment technologies remove particulates,
but do not reduce odorous or harmful gaseous contaminants, like
volatile organic compounds (VOCs), carbon monoxide (CO), or ozone
(O.sub.3). Those that do address these additional contaminants
produce significant disadvantages. Adsorbent filters require
frequent replacement, have high-pressure drops, and have difficulty
removing the lighter of the VOCs, CO, and O.sub.3. Catalytic
systems have longer lifetimes, less maintenance, and treat a wider
variety of contaminants. However, a drawback has been the energy
cost of heating the airflow to reaction temperature on a full-time
basis.
[0003] U.S. Pat. No. 5,742,516 for Indoor Air Quality And
Ventilation Assessment Monitoring Device discloses sensors, the
outputs of which control an air handler which governs air flow
rates and thus ventilation rate. Fundamentally, the '516 patent
discloses a device which improves air quality by diluting a
contaminated air stream with a less contaminated air stream. The
'516 patent device relies on a mixing of external air and internal
air using the air handler to control fan speed, dampen settings and
filtration depending on detectors which monitor the extent of a
selected air contaminant such as carbon monoxide, methane or
ozone.
[0004] U.S. Pat. No. 5,976,010 for Energy Efficient Air Quality
Maintenance System And Method discloses a heating, ventilation and
air conditioning system which employs air contaminant sensors and
compares their measurements to setpoints or standards. The focus is
on the air contaminant CO.sub.2 and the air quality improvement is
also through dilution with less contaminated air (i.e., less
CO.sub.2).
[0005] U.S. Pat. No. 3,772,851 for Dust Monitoring System And
Method discloses the removal of particulates from industrial
exhaust. The system compares overall particulate level to a
standard and then varies the amount of contaminated flow to treat
depending upon the extent of overall contamination sensed.
[0006] As can be seen, there is a need for an air cleaning system
that eliminates VOCs and other gaseous contaminants, as well as
particulates.
SUMMARY OF THE INVENTION
[0007] The present invention improves air quality by eliminating
unwanted VOCs that are of high health and safety concern. In one
aspect of the present invention, the energy burden that catalytic
oxidation requires is reduced through integration of sensors to
measure contaminant concentrations and occupancy, and a control
methodology to match treatment efficiency to a specified air
quality standard. The controller may be programmed with many
algorithms, including prediction of catalyst efficiency, which
increases with increasing temperature and decreasing flowrate.
[0008] In another aspect of the present invention, the VOC
concentration in the treatment space decreases with increasing
number of air exchanges through the system; and larger differences
between actual VOC concentration and desired concentration require
more air treatment. In this way the present invention operates when
air treatment is needed and conserves power when air quality is
acceptable. Unlike the device of the '516 patent disclosure, the
present invention employs sensor outputs to control an air cleaner.
Control of the air cleaner is achieved by monitoring air
contaminant concentrations in both the inlet and outlet of the air
cleaner, and by knowledge of the air cleaner's efficiency that,
under a given set of conditions, can predict contaminant
concentrations in the outlet and enclosed space.
[0009] Thus, in yet another aspect of the present invention the air
cleaner of the present invention may self-select operating
conditions (flow rate and temperature) that achieve the desired air
quality or that minimize energy in achieving satisfactory air
quality.
[0010] These and other features, aspects and advantages of the
present invention will become better understood with reference to
the following drawing, description and claims.
BRIEF DESCRIPTION OF THE DRAWING
[0011] The Figure herein is a block diagram of an embodiment of the
present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0012] The following detailed description is the best currently
contemplated modes for carrying out the invention. The description
is not to be taken in a limiting sense, but is made merely for the
purpose of illustrating the general principles of the
invention.
[0013] It will be seen that the present invention differs in a
number of ways from the prior art. One such difference relates to
the use of air flow heating to permit catalyst reaction to remove
VOCs and CO, the use of temperature sensors to provide a proper
amount of heating, and the inclusion of a heat exchanger to recover
a portion of the energy employed to heat the air stream. Another
difference is the use of a controller to receive sensor data, and
to control the heater and air stream flow rate to clean the air
stream using catalyst reaction and adsorbent. Still another such
difference is use of the controller to run an algorithm which can
achieve desired air quality in minimum time or with minimum energy
expenditure.
[0014] Referring to the Figure, a smart air cleaning system 5 in
accordance with the present invention is shown. Its components in
one embodiment may comprise pressure sensors 11 and 21 on either
side of a particulate filter 20; temperature, composition and flow
rate sensors 22, 23 and 24 in front of or upstream of a heat
exchanger 30; temperature sensors 31 and 32; a heater 40; a blower
50; catalyst devices 60 and 70; adsorbent device 80; temperature
and composition sensors 81 and 82; and a controller 91.
[0015] Typical operation may be as follows. An air stream 10--such
as from a land vehicle, aircraft, or building--is brought into the
particulate filter 20 to remove mists and particulates. The
particulate filter 20 may be of a well-known design such as, --a
pleated, panel filter--. The air stream pressure on either side of
the filter is measured by sensors 11 and 21. The air temperature,
composition, and flowrate are measured by sensors 22, 23 and 24,
respectively. Alternatively, composition sensor 23 may be located
in one or more locations throughout the space to be treated. The
air stream 10 is then preheated by heat exchanger 30--such as an
air-to-air heat exchanger of any well-known design--and the
resulting temperature is read by sensor 31. Depending upon the
difference between temperature at sensor 31 and the required
operating temperature, the stream may be further heated by heater
40, such as an electric or gas fired heater.
[0016] In installations where the present invention does not
receive forced air, the air stream 10 may be moved through the
present invention with the blower 50, such as one having either an
axial or centrifugal design. The VOCs and CO may be oxidized over
catalyst 60, where O.sub.3 may be decomposed over catalyst 70.
Useful catalysts 60 may include noble metals such as platinum and
gold or transition metals such as manganese, iron, and cobalt,
supported on high surface-area metal oxides such as alumina,
silica, and titania and in a bed-type arrangement, for example.
Useful catalysts 70 may include noble metals such as palladium and
silver or transition metals such as manganese or copper supported
on high surface-area metal oxides such as alumina, silica, and
titania and in a bed-type arrangement, for example. Alternatively,
the catalysts 60, 70 may be placed in the opposite order or
combined into a single unit. By-products such as acid gases or
nitric oxides are removed by the adsorbent 80. The temperature and
composition of the treated air are read by sensors 81 and 82,
respectively. Energy is recovered from the treated stream by
passing it through heat exchanger 30. The temperature of the
treated air is read by sensor 32 before returning that air to the
environmental space 90.
[0017] Data from the sensors are collected by controller 91. The
controller is also the user interface and allows for programming of
algorithms, control actions, and setting of air quality standards.
The controller 91 may have a microprocessor to facilitate such
programming. A further input into the controller can be the
occupancy level of the environmental space, which allows efficient
operation of the invention when the space is occupied. The
controller 91 may automatically adjust the temperature and flowrate
of the air stream to achieve or maintain the desired air quality in
a timely manner. Further, the standards (setpoints) and control
methodology may be programmed remotely, e.g., in a wireless fashion
using an Internet connection. In one embodiment, the controller may
be programmed to take into account the known efficiencies of
respective catalyst devices based upon variations in air stream
temperature and flow rate.
[0018] The smart air cleaning system 5 may be deployed in different
ways. The terminal mode and the central mode are two examples of
possible deployment. In the terminal mode, the present invention
operates as a stand-alone unit and can be made to be portable. In
the central mode, the present invention is incorporated directly
into the heating, ventilation and air conditioning ductwork of a
vehicle, building or other structure, as examples. Forced air
circulation and some heating are provided to the unit. In either
mode, the sensors and control methodology allow the present
invention to be customized for a specific problem statement.
[0019] It will now be apparent that the invention has been
described in regard to one illustrative embodiment. It will be
understood that other embodiments are contemplated and those having
the benefit of the above disclosure will readily perceive such
other embodiments. By way of example, where the present invention
is integrated into an existing structure having an existing air
flow and heating system, the blower and the heater of the existing
system may be made a part of the invention thereby obviating the
need for a separate blower and heater as described herein in regard
to the preferred embodiment.
[0020] Thus, the scope of the invention hereof is to be limited
only by the appended claims and their equivalents.
* * * * *