U.S. patent application number 11/438841 was filed with the patent office on 2008-01-17 for system for improving both energy efficiency and indoor air quality in buildings.
Invention is credited to Frank E. Spadafora, Paul F. Spadafora, Ronald M. Spadafora.
Application Number | 20080014857 11/438841 |
Document ID | / |
Family ID | 38949844 |
Filed Date | 2008-01-17 |
United States Patent
Application |
20080014857 |
Kind Code |
A1 |
Spadafora; Paul F. ; et
al. |
January 17, 2008 |
System for improving both energy efficiency and indoor air quality
in buildings
Abstract
A building's Heating Ventilating and Air Conditioning (HVAC)
system is made more energy efficient and the indoor air quality
(IAQ) of the building's circulating air is improved by
incorporating a greenhouse as an integral part of the HVAC system
and by utilizing a novel feed forward control strategy that
maintains the proper levels of temperature, humidity and CO.sub.2
concentration in the building under varying conditions of day,
time, use and occupancy. A portion or all of the exhaust air from
the building is discharged into a greenhouse where the heat and
humidity are recovered in the winter by heating the greenhouse and
the air conditioning is recovered in the summer by cooling the
greenhouse. Selected plants are used in the greenhouse to remove
CO.sub.2 and pollutants from the building's exhaust air while
enriching the air with oxygen and beneficial negatively charged
ions. The oxygenated, improved quality air from the greenhouse is
then used to supply all or a portion of the intake air to the
building's HVAC system.
Inventors: |
Spadafora; Paul F.;
(Lagrangeville, NY) ; Spadafora; Ronald M.;
(Lagrangeville, NY) ; Spadafora; Frank E.; (Pella,
IA) |
Correspondence
Address: |
Ronald M. Spadafora
12 Alley Road
Lagrangeville
NY
12540
US
|
Family ID: |
38949844 |
Appl. No.: |
11/438841 |
Filed: |
May 23, 2006 |
Current U.S.
Class: |
454/229 |
Current CPC
Class: |
F24F 11/77 20180101;
F24F 2110/70 20180101; F24F 2110/50 20180101; F24F 8/175 20210101;
Y02B 30/70 20130101; F24F 3/16 20130101; F24F 11/30 20180101 |
Class at
Publication: |
454/229 |
International
Class: |
F24F 11/02 20060101
F24F011/02 |
Claims
1. An HVAC system for buildings and other structures consisting of
traditional HVAC components in conjunction with a greenhouse as in
integral part of the system consisting of: a) a heating
humidification section (oil, gas, coal, wood, electric, heat pump,
geothermal, solar or any other type) b) an air conditioning section
(air conditioner, heat pump, geothermal or any other type) c) Fans
or any other type of air movers, preferably variable speed, for air
circulation, exhaust air and inlet air. d) Air circulating ductwork
with appropriate air filters and grilles. e) Controllable dampers
and valves. f) Individual room radiators (optional). g) Sensors for
temperature, humidity, CO.sub.2, air flow, hot water flow and for
any heating and cooling medium flows. h) A computer or any other
type of programmable controller with algorithms to minimize air
circulation rates, exhaust air rates and inlet air rates while
maintaining the desired targeted room temperatures, humidity and
CO.sub.2 levels which will normally vary depending on day, time,
use and occupancy. i) An attached or separate greenhouse with
appropriate ductwork to accept 0 to 100% of the building exhaust
air and a means to supply 0 to 100% of the building's supply air
requirements. j) Selected plants in the greenhouse that have the
ability to absorb CO.sub.2 and other air pollutants at a high rate
and plants that have the ability to emit oxygen and beneficial
negatively charged ions into the air at a high rate. All of the
above components are not necessary to practice the teachings of
this patent.
2. A system of claim 1 whereby the greenhouse preferably has an
enclosed volume of more than two times the design hourly flow of
the building exhaust air.
3. A system of claim 1 whereby the greenhouse preferably has a
plant growing area of more than 4 square feet for each 100 cubic
feet of design hourly flow of building exhaust air.
4. A system of claim 1 where greenhouse plants are selected on the
basis of high CO.sub.2 and other pollutant uptake rates and their
ability to emit oxygen and beneficial negative ions and for their
commercial value or any combination. Typically these are leafy fast
growing plants, trees, fruits or vegetables and preferably where
the leaves have a large total surface area and account for a large
portion of the above ground biomass of the plant.
5. A system of claim 1 whereby plants suitable for this purpose but
not limited to are as follows: TABLE-US-00002 Family Examples
(Common Name) Nephrolepis Boston Fern Dragaena Mothers In Law's
Tongue, Snake plant and Janet Craig Hedra English Ivy Fieus Weeping
Fig Phoenix Dwarf Date Palm Vegetables Lettuce, Spinach, Kale,
Zucchini and other squash
Or any other plants found to absorb CO.sub.2 and other pollutants
and emit O.sub.2 and beneficial negative ions and have some
commercial value or any combination.
6. A system of claim 1 whereby at night or during periods of low
light or for any other reason when the CO.sub.2 concentration of
the greenhouse air available for inlet air makeup air to the
building HVAC system is too high, high efficiency sunlamps can be
turned on to enhance or extend the conditions for plant growth
thereby increasing the rate of CO.sub.2 removal from the greenhouse
air and increasing the rate of O.sub.2 and beneficial negatively
charged ions addition into the greenhouse air.
7. An HVAC system of claim 1 whereby sensors for measuring
temperature, humidity, CO.sub.2 airflow and the flow of any other
heating or cooling medium are located strategically throughout the
system and continuously transmit the values of each of the
parameters to a central computer controller where algorithms are
stored and continuously updated to determine the slope of the
curves for the changes in temperature, humidity and CO.sub.2 levels
in the building and in the greenhouse.
8. A system of claim 1 and 7 whereby the slope or the rate of
change in any measured parameter is used to control the rate of any
of the controllable factors such as air flow or other fluid flows,
the temperature of the air and other fluids, the humidity of the
air and the CO.sub.2 level of the air.
9. A system of claim 1 and 7 whereby algorithms in the controller
determine the regulation priorities so as to maintain the proper
temperature, humidity and CO.sub.2 levels at the lowest air
circulation rate, lowest air exhaust rate and lowest makeup air
rate to improve energy efficiency so as to maintain good air
quality using the lowest practical total energy consumption based
on the sum of the energy used by all the components in the entire
system.
10. A system of claim 1 and 7 whereby the desired temperature,
humidity and CO.sub.2 level is used as a feed forward target and
not as a set point subject to overshooting, undershooting and
cycling which leads to occupant discomfort and lower energy
efficiency.
11. A system of claim 1 and 7 whereby the amount of the building
exhaust air discharged into the greenhouse is controlled at the
minimum rate required to maintain the ASHRE recommended CO.sub.2
level in the air in each room of the building or preferably below
0.4%. Preferably the exhaust air is directed to the lower portion
at one end of the greenhouse so that the higher density CO.sub.2 in
the exhaust air comes quickly in contact with the ground level
plants stimulating faster removal of the CO.sub.2 and pollutants
from the exhaust air, encouraging faster growth of the plants and
promoting more emissions into the air of oxygen and beneficial
negatively charged ions by the plants.
12. A system of claim 1 and 7 whereby the amount of makeup air from
the greenhouse to the building's HVAC system is controlled at the
minimum necessary to maintain the desired ASHRE recommended
CO.sub.2 level in the air of each of the rooms of the building or
preferably below 0.4%. Preferably the makeup air to the building is
drawn from the upper portion of the opposite end of the greenhouse
from the exhaust air inlet so that the lighter density lower
CO.sub.2 and higher oxygenated air containing beneficial negative
ions is drawn into the building's HVAC system.
13. A system of claim 1 and 7 whereby the air circulation rate and
the flow rate of any other heating and cooling fluid in each of the
rooms is controlled at the minimum necessary to maintain the proper
temperature, humidity and CO.sub.2 level dependant on day, time,
use and occupancy.
14. A system of claim 1 and 7 where a two-way proportioning exhaust
damper is used so that when ambient air conditions of temperature,
humidity or CO.sub.2 level may be beneficial, a portion or all of
the exhaust air from the building can be divided between the
greenhouse and the ambient air.
15. A system of claim 1 and 7 whereby a two-way proportioning inlet
damper is used so that when ambient air conditions of temperature
humidity and CO.sub.2 levels are beneficial all or any portion of
the inlet air to the building can be drawn from the greenhouse and
ambient air.
Description
US PATENT DOCUMENTS
TABLE-US-00001 [0001] 5005787 Apr. 9, 1991 Cullingford 5433923 Jul.
18, 1995 Wolverton 5853460 Dec. 29, 1998 Alcordo 6415617 Jul. 9,
2002 Seem 6727091 Apr. 27, 2004 Darlington
OTHER REFERENCES
[0002] Final Report NASA/Alca "Interior Landscape Plants for Indoor
Air Pollution Abatement" Wolverton Et al. 1989
[0003] Biofiltration of Air Pollution Control, J. S. Devinny et al.
1999
[0004] Biofiltration of Indoor Air. Llewellyn et, al. date
unknown
[0005] Development of Biofiltration system of ammonia and VOC. J.
R. Kastner March 2003
FIELD OF INVENTION
[0006] The present invention relates to HVAC systems and Indoor Air
Quality (IAQ) in structures and buildings and more particularly it
pertains to a system and method whereby a greenhouse and a unique
control system is integrated into the HVAC system to improve energy
conservation, reduce CO.sub.2 and pollutants and increase oxygen
and beneficial negative ions in the circulating air of the building
or structure.
BACKGROUND OF THE INVENTION
[0007] Because of the rising costs of energy, modern buildings are
increasingly designed to be more airtight in order to retain the
heat in the winter and to retain air conditioning in the summer.
However, proper ventilation becomes more difficult as the building
gets more airtight. In winter, when heating is required, reducing
the amount of warm, moist exhaust air to the atmosphere and
restricting the amount of cold, dry atmospheric makeup air aids
energy conservation but leads to the increase in the concentration
of CO.sub.2 and other pollutants in the circulating air resulting
in unhealthy conditions. In the summer when air conditioning is
required, reducing the amount of cold, dry exhaust air to the
atmosphere and restricting the amount of hot, moist inlet makeup
air from the atmosphere also saves energy but also leads to an
increase in the concentration of CO.sub.2 and other pollutants in
the building circulating air resulting in unhealthy conditions.
[0008] Sensors are available to measure CO.sub.2, temperature and
humidity and have been used to try to minimize the amount of
exhaust air from the building to the atmosphere and also minimize
the amount of inlet makeup air from the atmosphere into the
building. The recommended allowable ranges of temperature, humidity
and CO.sub.2 for various types of buildings for various uses are
available from the American Society of Heating, Refrigerating and
Air-Conditioning Engineers (ASHRAE). However, to maintain the
desired ranges, exhaust air is normally discharged into the
atmosphere and inlet air to the building HVAC system is normally
drawn from the atmosphere. This atmospheric inlet air must be
heated and humidified in the winter and must be cooled and
dehumidified in the summer. Heat exchangers can be used to preheat
or pre-cool the incoming air with the exhaust air, depending on the
season. These heat exchange systems are relatively expensive to
install and maintain, require a great deal of space and only a
relatively small amount of heat or cooling is recovered. The heat
exchangers are also subject to fouling, which reduces the heat
transfer and require periodic cleaning adding to maintenance
costs.
[0009] U.S. Pat. No. 5,005,787 (Cullingford) describes a life
support system for a spacecraft where a greenhouse is used as a
integral part of the spaceship. This patent calls for a completely
hermetically sealed greenhouse unit and states it is specifically
for spacecraft. It requires complex support systems including
ultraviolet radiation, a catalytic burner, an electrolyzer system
for water and a fuel cell system. One of the main purposes for the
greenhouse is to grow fresh vegetables for the space crew.
Supplemental removal of carbon dioxide from the air by mechanical
and chemical means is required. This patent also requires extensive
processing of water and humidity and the reduction of water to
hydrogen and oxygen. This patent clearly specifies it pertains to a
spacecraft crew cabin and other spacecraft systems and does not
pertain to or address normal ground based buildings and HVAC
systems as does our invention.
[0010] Studies by NASA also indicated that negative ions in the air
are required for good health and well-being. The studies indicated
synthetic building materials and furniture have positive static
charges that remove large quantities of beneficial negative ions
from the indoor environment. Therefore, the negative ion count in
many buildings is often too low for the well being of the
occupants. It was also found that plant leaves produce beneficial
negative ions when they emit water vapor.
[0011] Therefore, plants that emit water vapor at high rates tend
to produce the most negative ions per unit. Studies by Wolverton
have shown that houseplants in rooms can reduce human stress and
increase productivity in an office environment. These beneficial
effects have been credited to the increase in negative ion levels
in the air.
[0012] Wolverton Environmental Services has done work on the use of
indoor plants to reduce the amount of toxins in the air inside
buildings. These studies and U.S. Pat. No. 5,433,923 (Wolverton)
all involve the use of houseplants inside the rooms of buildings.
U.S. Pat. No. 6,727,091 (Darlington) describes a system of using
hydroponic plants for cleansing the air in a room. This patent is
for a relatively small vertical panel which can be as small as 50
centimeters height times 50 centimeters wide and 1.5 centimeters
thick and can be configured as a wall unit or a free standing tower
which contains fibrous inert material where hydroponic plants are
grown to refresh stale air in a room. This method basically has the
same effect as having houseplants in the room. The unit described
in this patent has no relationship to the HVAC system of the
building and has the disadvantage in that it can promote mold
growth and release mold spores into the room. U.S. Pat. No.
5,853,460 (Alcordo) also describes a relatively small system of
plants and potting medium in flower pots in a room to cleanse the
air with no relationship to the HVAC system.
[0013] Our patent teaches the use of a separate greenhouse as an
integral part of the HVAC system of the building. This separate
greenhouse recovers the heating or cooling energy from the exhaust
air of the building and also has the advantage of providing much
more plant growing area as well as an opportunity to filter out any
mold spores that may be in the air.
[0014] U.S. Pat. No. 6,415,617 (Seem) describes a method whereby a
model in an HVAC control system is used to determine the minimum
and maximum outdoor makeup air to be used in the HVAC system. This
model determines the fraction of outdoor air that can be used to
minimize the HVAC load. This patent also has the disadvantage in
that it has to heat up and humidify the cold, dry ambient air in
the winter and cool down and dehumidify the hot, moist ambient air
in the summer.
[0015] Our invention describes how a greenhouse and a novel control
system can be used in conjunction with a normal building's HVAC
system to improve energy efficiency while improving the quality of
the circulating ventilation air in the building.
SUMMARY OF THE INVENTION
[0016] This invention describes a system whereby a greenhouse is
integrated into and is a functional part of a building's HVAC
system. The greenhouse serves as a means to recover heat and
humidity from the building's heated exhaust air in the winter and a
means to recover the cooling from the building's air conditioned
exhaust air in the summer. The greenhouse contains selected plants
that have the ability to remove CO.sub.2 and other airborne
pollution from the exhaust air and to emit oxygen and beneficial
negatively charged ions into the air. The resultant oxygenated air
containing the beneficial negatively charged ions is then used to
supply all or a portion of the makeup air to the building's HVAC
system. Energy consumption is further minimized and indoor air
quality in the building is kept at a high level by using
temperature, humidity and CO.sub.2 concentration sensors at
strategic points in the HVAC system and greenhouse and using a
computer controller containing algorithms that use a novel feed
forward control strategy. This control strategy uses the rate of
change in the slope of the temperature, humidity and CO.sub.2 level
curves to modulate the control devices. The change in the magnitude
of the slope prior to reaching the target levels of temperature,
humidity and CO.sub.2 is used to predict the equilibrium control
points and this information is used for feed forward control rather
than waiting for feed back information from set points before
taking action. This method prevents overshooting and cycling around
the set points while maintaining good indoor air quality. By
controlling building air circulation, air exhaust and inlet air
makeup rates at the minimum required to maintain the target levels
of temperature, humidity and CO.sub.2 concentration, energy
consumption is kept at the lowest practical level.
DESCRIPTION OF DRAWINGS
[0017] FIG. 1 Side view schematic of a school building HVAC system
with a greenhouse.
[0018] FIG. 2 Front view schematic of a school building HVAC system
with a greenhouse.
[0019] FIG. 3 Piping schematic of a school building HVAC system
with a greenhouse.
[0020] FIG. 4a Graph of the variation of the classroom temperature
for a typical school day.
[0021] FIG. 4b Graph of the variation of the hot water flow to the
classroom radiators for a typical school day.
[0022] FIG. 5a Graph of the variation of the humidity of the
classroom air for a typical school day.
[0023] FIG. 5b Graph of the humidity of the inlet air to the
classroom for a typical school day.
[0024] FIG. 6a Graph of the variation of the CO.sub.2 level in the
classroom for a typical school day.
[0025] FIG. 6b Graph of the variation of the inlet air flow into
the classroom for a typical school day.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THIS
INVENTION
[0026] Using a school building as one example of a type of
structure that can be used in the preferred embodiment of this
invention, refer to FIGS. 1, 2, 3, 4a, 4b, 5a, 5b, 6a, 6b. For a
school building (1) starting on Monday morning during the heating
season, the empty classrooms (2) would be at a lower temperature
and humidity with minimum circulating air flow. The building air
circulation rate, the exhaust air rate and the inlet air rate of
the HVAC system (3) would be minimal with low energy consumption.
At a preset time before school starts, the computer controller (4)
signals the HVAC system (3) to adjust the hot water flow control
valve (5) to increase the flow of hot water to the radiators (6) to
raise the temperature in the classrooms (2). At the control hot
water flow rate, the temperature in the classrooms (2) is below the
target value. As teachers and students arrive and the room is being
occupied the temperature, humidity and CO.sub.2 in the classroom
(2) will increase due to the body heat and respiration of the
occupants. As the temperature in the classrooms (2) begins to
increase, due to the arrival of more and more students, the slope
of the temperature curve is used by the algorithms in the computer
controller (4) to determine how much to throttle back on the hot
water flow to the radiators (6) to prevent overshooting the
temperature target. When equilibrium is obtained, the hot water
flow rate remains relatively constant until the class is dismissed
at the end of the school day. The computer controller (4) then
reduces the hot water flow rate and the classroom (2) is allowed to
cool down to the nighttime lower target temperature to conserve
energy. (See FIGS. 4a and 4b). If a hot air heating system is used
instead of a hot water heating system, the same principles are used
except instead of controlling the hot water flow the temperature
and flow of the hot air is controlled.
[0027] In a similar manner with the arrival of the students, the
humidity and CO.sub.2 concentration of the air in the classrooms
(2) will increase. The slope of the humidity and CO.sub.2
concentration curves are used by the computer controller (4) to
regulate the humidity and the flow rate of the circulating inlet
air to the classrooms (2). The circulating air flow into the
classrooms would increase fairly rapidly as the occupants increase
because of the sudden rise in the CO.sub.2 concentration in the air
in the room. The airflow into the room would throttle back as it
approaches the target levels for CO.sub.2 and humidity and then
would be fairly constant when equilibrium is obtained. At the end
of the school day when the children are dismissed,.the circulating
airflow to the classrooms (2) would be reduced to the lower
nighttime settings to conserve energy. The circulating airflow rate
is primarily controlled by varying the speed of the air circulating
fans (7). Preferably these fans would have different capacities to
extend the controllable air circulation rate from very low when the
building (1) is unoccupied to much higher rates when the building
(1) is fully occupied. The classroom (2) air flow control dampers
(8) are mainly used to trim the airflow to the classrooms (2) or to
minimize airflow to low occupancy classrooms (2) or to seal off
empty classrooms (2) during the school day to reduce unnecessary
circulating airflow through low occupancy or empty classrooms (2)
thereby saving energy (see FIGS. 5a, 5b, 6a and 6b).
[0028] The temperature sensors (9), humidity sensors (10) and
CO.sub.2 sensors (11) related to the classrooms (2) continuously
transmit data to the computer controller (4), which also receives
data on temperature, humidity and CO.sub.2 from sensors in the
exhaust air ducts (12), the recycle air duct (13) and HVAC inlet
air duct (14) as well as from the greenhouse (15) and ambient air
(16) in order to continuously update the control parameters to
maintain high quality indoor air and minimize energy consumption.
At night and before the school day starts, the circulating airflow
rate is very low, the fresh makeup air flow rate from the
greenhouse is very low and the exhaust air flow rate, which is
equal to the makeup air rate, is also very low and a high
proportion of the circulating air is being recycled through the
recycle air duct (13). As the classrooms (2) begin to be occupied
and the concentration of the CO.sub.2 in the exhaust air from the
classrooms increases the speed of the air circulating fans (7)
increase and the inlet air flow control damper (17) opens wider to
increase the flow of fresh air from the greenhouse (15) by way of
the inlet air two-way proportioning damper (18) and inlet air duct
(14) and the variable speed exhaust fans (19) increase speed and
the exhaust airflow control damper (20) opens to increase the flow
of exhaust air through the exhaust air duct (12) and out of the
exhaust air two-way proportioning damper (21) into the greenhouse
(15) and the recycle airflow control damper (22) closes down to
reduce the amount of recycled air. At the end of the school day,
the process is reversed and the fan speeds and damper settings will
slope back to the nighttime settings to conserve energy.
[0029] In the greenhouse (15), the exhaust air from the building
(1), containing a high level of CO.sub.2 and possible airborne
pollutants such as volatile organic compounds (VOC), is directed to
the lower ground level where selected species of plants (23) are
grown which remove the CO.sub.2 and pollutants from the exhaust
air. The plants (23) use the CO.sub.2 and water and nutrients from
the soil for growth and in combination with the bacteria in the
soil around the roots of the plants (23) transform the pollutants
into harmless compounds. The photosynthesis process in the selected
plants (23) takes up the CO.sub.2 and emits oxygen into the air and
the selected plants (23) also have the ability to emit beneficial
negatively charged ions into the air. The oxygenated air containing
the beneficial negatively charged ions is less dense than the
CO.sub.2 laden exhaust air and will tend to rise in the greenhouse.
The opening to the inlet air duct (14) to the building (1) is
therefore placed higher and at the opposite side of the greenhouse
(15) to reduce intermingling of the exhaust air with the fresh
makeup air to the building (1).
[0030] During periods of low light or at night, high efficiency
sunlamps (24) can be activated to improve plant growth and to
extend the time available for CO.sub.2 and pollutant removal. As a
further refinement an inlet air two-way proportioning damper (18)
can be utilized to divide 0 to 100% of the inlet makeup air to the
building between the greenhouse (15) and the ambient air (16).
Similarly an exhaust air two-way proportioning damper (21) can be
utilized to divide 0 to 100% of the exhaust air from the building
into the greenhouse (15) or the ambient air (16). The decision on
whether to turn on the high efficiency sunlamps (24) or use the
inlet air two-way proportioning damper (18), and exhaust air
two-way proportioning damper (21) or any combination is determined
by the algorithms in the computer controller (4).
[0031] The algorithms in the computer controller will continuously
calculate what settings to use for the hot water flow control
valves (5), the inlet air flow control dampers (17), the exhaust
air flow control damper (20) and the inlet air controllable two-way
proportioning damper (18), the exhaust air controllable two-way
proportioning damper (21), as well as the speeds of the variable
speed air circulating fans (7) and variable speed exhaust air fans.
(19) The settings on all the controllable equipment are adjusted so
as to insure that the CO.sub.2 concentration and the air quality in
each of the classrooms (2) are at a high standard and the
temperature and humidity targets are being achieved using the
lowest practical total energy consumption based on the sum of the
energy used by all the equipment in the entire system.
[0032] FIG. 4a represents a graph of the variation of the
temperature of the classrooms (2) during a typical school day. FIG.
4b represents a graph of the hot water flow to the radiators (6) in
the classrooms (2) during a typical school day. FIG. 5a represents
a graph of the variation of the humidity of the classrooms (2)
during a typical school day and FIG. 5b represents a graph of the
humidity of the inlet air flow to the classrooms (2) for a typical
school day. FIG. 6a represents a chart of the variation of the
CO.sub.2 level of the air in the classrooms (2) during a typical
school day. FIG. 6b represents a graph of the variation of the
inlet air flow into the classrooms (2) for a typical school
day.
[0033] On weekends and holidays, all of the parameters default to
the nighttime settings when the classrooms (2) are not occupied.
The same basic control strategy is used in the offices (25) and the
gymnasium/cafeteria (26) and other zones of the building (1).
During the cooling season the same strategy is used except for
cooling rather than heating.
[0034] The airflow indicators (27) throughout the system aid in
establishing empirical values required by the algorithms in the
computer controller (4) and for troubleshooting operational
problems that may come up due to mechanical failures or other
causes.
* * * * *