Controlled Environment Systems Research Facility Hypobaric Chambers for Biological Life Support Research Michael Stasiak, Cara Ann Wehkamp, Jamie Lawson, and Michael Dixon Controlled Environment Systems Research Facility Department of Environmental Biology University of Guelph
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Controlled Environment Systems Research Facility Hypobaric Chambers for Biological Life Support Research Michael Stasiak, Cara Ann Wehkamp, Jamie Lawson,
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Controlled Environment Systems Research Facility
Hypobaric Chambers for Biological Life Support Research
Michael Stasiak, Cara Ann Wehkamp, Jamie Lawson, and Michael Dixon
Controlled Environment Systems Research Facility Department of Environmental Biology
University of Guelph
Controlled Environment Systems Research Facility
Bioregenerative Life Support Systems
Edible Biomass Production Carbon Dioxide Absorption Oxygen Generation Water Recycling Waste Degradation
CO2O2
Edible Biomass
Processed Waste
Gray H2O
Pure H2O
Inedible Biomass
Controlled Environment Systems Research Facility
Plant Growth Structure on Mars
Two options exist:
Earth atmospheric pressure- heavy and opaque
Reduced atmospheric pressure- light-weight and transparent material
Controlled Environment Systems Research Facility
Benefits of Low Atmospheric Pressure
Need to minimize the pressure differential between the growth structure and the Martian atmosphere
- simplifies the engineering requirements of the structure
- decreases atmospheric leakage
- reduces the amount of supplemental gas required for startup
- ability to modify plant growth rates
Martian Atmosphere (0.6 kPa)
10 kPa
Plant Growth Structure
100 kPa
Controlled Environment Systems Research Facility
Mars is the best candidate for human exploration
Low pressure conditions may be advantageous to Martian habitation
Further investigation is required for the development of an atmospheric composition that allows for reduced pressure plant growth without compromising the plant production yields required for human life support
Summary
Controlled Environment Systems Research Facility
Chamber design Data acquisition and control Temperature and humidity Pressure Carbon dioxide and oxygen Lighting Nutrient delivery
Hypobaric chambers: design and function
Controlled Environment Systems Research Facility
Five full canopy plant growth chambers 1.0 x 1.8 x 2.5 m (WHD) 4500 litre volume Growing area of 1.5 m2
Highly closed systems with low leakage Internal surfaces 316 stainless steel 20.5 mm laminate glass roof panels Viton sealing rings on doors and glass Fully automated Capable of maintaining low pressures
Hypobaric chamber design
Controlled Environment Systems Research Facility
Co
nd
en
se
r
He
ate
r
Blower
InternalReservoir
DO
OR
Lighting System Canopy
2.5 m
1.8 m
External Hydroponics Reservoir
Blower
Co
olin
g C
oil
1.5 m
Vacuum
Nitrogen
CO2
Oxygen
GasSampling
Controlled Environment Systems Research Facility
Data acquisition and control
Argus Control Systems Inc. Distributed real-time control Stand-alone microcontroller (Motorola 68HC811) on
each chamber Proprietary RS 485 communications network Each hypobaric chamber operates independently All sensor readings sampled once per second Experimental data recorded once per minute (higher
speeds available) Operator interface provided through a PC-based
system access and management program (Argus for Windows)
PC component is not used for real time control - failure of the PC has no consequence on system control
Controlled Environment Systems Research Facility
Temperature and humidity
Variable speed blower Blower speed control coupled to pressure Chilled water (4°C) and hot water (55°C)
heat exchange coils Cold exchange coil controlled to achieve
required VPD setpoint Hot exchange coil used to reheat cooled
air to regulate final temperature setpoint Two Honeywell 4139 T/RH sensors Four Argus TN2 temperature sensors (2
soil, 2 heat exchange) Tipping bucket for evapotranspiration
measurement
Controlled Environment Systems Research Facility
17
18
19
20
21
22
23
24
25
0 2 4 6 8 10 12 14 16 18
ambient
66 kPa
33 kPa
Temperature: Radish
Days after closure
Tem
pera
ture
(°C
)
Controlled Environment Systems Research Facility
7
8
9
10
11
12
0 2 4 6 8 10 12 14 16 18
ambient
66 kPa
33 kPa
Vapour pressure deficit: Radish
Days after closure
VP
D (
mb)
Controlled Environment Systems Research Facility
50
55
60
65
70
75
80
0 2 4 6 8 10 12 14 16 18
ambient
66 kPa
33 kPa
Relative humidity: Radish
Days after closure
%R
H
Controlled Environment Systems Research Facility
0
2
4
6
8
10
12
0 6 12 18 24
ambient
66 kPa
33 kPa
Evapotranspiration: Radish 18 DAP
Hours
H2O
Acc
umul
atio
n (li
tres
)
Controlled Environment Systems Research Facility
Pressure
Vacuum pump: Busch Vacuum Pressure sensors: Pribusin Inc Control Valve: Swagelok Control range +/- 0.1 kPa Pressure control ambient to 0.01 kPa Systems not designed for pressurization Leakage rate less than 1% per day
Controlled Environment Systems Research Facility
64.0
64.5
65.0
65.5
66.0
66.5
67.0
0 6 12 18 24
32.0
32.5
33.0
33.5
34.0
0 6 12 18 24
66 kPa
33 kPa
Hours
kPa
System leakage
Controlled Environment Systems Research Facility
9.0
9.5
10.0
10.5
11.0
0 6 12 18 24
4.0
4.5
5.0
5.5
6.0
0 6 12 18 24
10 kPa
5 kPa
Hours
kPa
System leakage
Controlled Environment Systems Research Facility
20
30
40
50
60
70
80
90
100
0 2 4 6 8 10 12 14 16 18 20
ambient
66 kPa
33 kPa
Pressure: RadishkP
a
Days after closure
Controlled Environment Systems Research Facility
Carbon dioxide and oxygen
CO2/O2 analyzer: California Analytical Instruments Inc. Model 200
NDIR CO2 and paramagnetic O2 sensors
One analyzer per chamber
CO2: 0 – 6000 µmol mol-1 (+/- 15 from set point)
O2: 0 -100%
Controlled Environment Systems Research Facility
Cold trapHypobaricChamber
CO2/O2 Analyzer
CO2
NC1
Cold trapNV2
Pump
O2
NC2
N2
NC3
Condensate return
NV1
CO2/O2 sampling system based on repressurization of hypobaric chamber air
Chamber air continuously removed by a vacuum pump (KNF Neuberger Inc)
Air is repressurized in a sampling loop controlled by a non-bleed precision pressure regulator (Parker) and needle valve (HAM-LET)
Pressure gauge (Noshok) used to monitor and manually set the sampling stream to 0.2 psi
Pressure regulator/gauge
Controlled Environment Systems Research Facility
1100
1200
1300
1400
1500
1600
1700
0 6 12 18 24
0
100
200
300
400
500
600
700
800
900
ambient
66 kPa
33 kPa
Carbon dioxide: Radish 18 DAP
Hours
µm
ol m
ol-1
mm
ol accumulated
Controlled Environment Systems Research Facility
20.0
20.5
21.0
21.5
22.0
22.5
23.0
23.5
24.0
0 6 12 18 24
ambient
66 kPa
33 kPa
Oxygen: Radish 18 DAP
Hours
Per
cent
oxy
gen
Controlled Environment Systems Research Facility
Lighting
six 1000 watt HPS lamps (P.L. Light Systems) per chamber
Maximum irradiation intensity at highest bench level approximately 1500 μmol m-2 s-1 PAR
Externally mounted lighting canopy cooled with chilled water heat exchanger coupled to a blower
Two LiCor PAR sensors continuously monitor irradiation
lighting schedule automated and under control of the Argus Control System.
NFT design 400 litre temperature controlled external stainless steel reservoir Circulation pump (International Pump Technology Inc.) provides
sufficient pressure for chamber delivery from ambient to 2 kPa Gravity return of water Electrical conductivity (2 - Argus Control Systems, Inc) pH sensors (2 - Honeywell Inc.) currently non-functional – pH is
manually adjusted daily Gravity feed of acid, base, and nutrient solutions
Nutrient delivery
Controlled Environment Systems Research Facility
Controlled Environment Systems Research Facility
0.8
0.9
1
1.1
1.2
1.3
1.4
0 5 10 15 20
ambient
66 kPa
33 kPa
Days after planting
Ele
ctric
al c
ondu
ctiv
ity (
mS
)EC: Radish
Controlled Environment Systems Research Facility
Nutrient delivery
Removable tray system Pump truck to move crop to harvest lab Quick-connect couplings for water delivery Gravity return to external tank