WO2020021253A1 - Chambre de croissance de plantes - Google Patents

Chambre de croissance de plantes Download PDF

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Publication number
WO2020021253A1
WO2020021253A1 PCT/GB2019/052064 GB2019052064W WO2020021253A1 WO 2020021253 A1 WO2020021253 A1 WO 2020021253A1 GB 2019052064 W GB2019052064 W GB 2019052064W WO 2020021253 A1 WO2020021253 A1 WO 2020021253A1
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WO
WIPO (PCT)
Prior art keywords
plant growth
gas
thermally
growth chamber
inlet
Prior art date
Application number
PCT/GB2019/052064
Other languages
English (en)
Inventor
Alexis Michael MOSCHOPOULOS
Richard Theodore BANKS
Original Assignee
Grobotic Systems Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Grobotic Systems Limited filed Critical Grobotic Systems Limited
Priority to GB2102206.6A priority Critical patent/GB2591623A/en
Publication of WO2020021253A1 publication Critical patent/WO2020021253A1/fr

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Classifications

    • A—HUMAN NECESSITIES
    • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01G—HORTICULTURE; CULTIVATION OF VEGETABLES, FLOWERS, RICE, FRUIT, VINES, HOPS OR SEAWEED; FORESTRY; WATERING
    • A01G9/00—Cultivation in receptacles, forcing-frames or greenhouses; Edging for beds, lawn or the like
    • A01G9/24—Devices or systems for heating, ventilating, regulating temperature, illuminating, or watering, in greenhouses, forcing-frames, or the like
    • A01G9/246—Air-conditioning systems
    • A—HUMAN NECESSITIES
    • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01G—HORTICULTURE; CULTIVATION OF VEGETABLES, FLOWERS, RICE, FRUIT, VINES, HOPS OR SEAWEED; FORESTRY; WATERING
    • A01G9/00—Cultivation in receptacles, forcing-frames or greenhouses; Edging for beds, lawn or the like
    • A01G9/24—Devices or systems for heating, ventilating, regulating temperature, illuminating, or watering, in greenhouses, forcing-frames, or the like
    • A01G9/26—Electric devices
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A40/00—Adaptation technologies in agriculture, forestry, livestock or agroalimentary production
    • Y02A40/10—Adaptation technologies in agriculture, forestry, livestock or agroalimentary production in agriculture
    • Y02A40/25—Greenhouse technology, e.g. cooling systems therefor
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P60/00—Technologies relating to agriculture, livestock or agroalimentary industries
    • Y02P60/14—Measures for saving energy, e.g. in green houses

Definitions

  • the present invention relates to a plant growth chamber, for growing plants or plant cells in soil, soilless culture, or sterile culture, under controlled environmental conditions.
  • Plant growth chambers are environmentally controlled chambers used by plant scientists to grow plants or plant cells in soil, soilless culture, or sterile culture, under carefully controlled environmental conditions.
  • a typical plant growth chamber allows for temperature and humidity inside the chamber to be controlled, along with the quality, intensity and duration of light.
  • the plant growth chamber can be heated and cooled by integrating the plant growth chamber into the climate control system of the building housing the plant growth chamber, but this requires complicated, dedicated infrastructure which can prove costly.
  • lighting units in existing plant growth chambers tend to run hot and are typically cooled by bulky and noisy high volume air ducts, which contribute to the size and cooling requirements of existing plant growth chambers.
  • the plant growth chamber may be used for growing plants or plant cells in soil, soilless culture, or sterile culture, under controlled environmental conditions.
  • the plant growth chamber comprises an interior region and a heat exchanger.
  • the heat exchanger comprises a fluid volume separated from the interior region.
  • a solid state heat pump is configured to transfer heat between the fluid volume and the interior region for controlling the environmental conditions in the interior region (for example, heating and/or cooling the interior region, and/or controlling the humidity of the interior region).
  • the interior region may comprise a plant growth region, where one or more plants or plant cells may be located.
  • the environmental conditions (such as temperature, humidity and/or lighting) of the plant growth region may be controlled, for example, as required by experiments that are being or to be conducted into the growth or health of the plants or plant cells.
  • the interior region may comprise a region adjacent a gas inlet (where air may be drawn in from outside the plant growth chamber, or a supply of another gas, such as carbon dioxide, may be provided).
  • the solid state heat pump may transfer heat between the fluid volume and inlet gas for heating and/or cooling the inlet gas into the plant growth chamber, and optionally for dehumidifying the inlet gas.
  • the interior region may comprise a region adjacent a gas outlet and the solid state heat pump may transfer heat between the outlet gas and fluid volume for recovering heat energy from the outlet gas, or more efficiently cooling the fluid volume.
  • the heat exchanger provides a way to control the temperature and/or humidity in the plant growth chamber which is more compact and lightweight than the vapour- compression based heating and cooling employed by existing plant growth chambers.
  • the plant growth chambers of the present invention are small and light enough to be stacked.
  • the plant growth chamber may have feet on the bottom of the plant growth chamber (for example, one foot adjacent to each corner of the plant growth chamber) which mate with corresponding recesses or fixtures on the top of another plant growth chamber.
  • the sides of the plant growth chamber may be constructed such that they are suitable for taking the weight of one or more plant growth chambers stacked on top.
  • the plant growth chamber of the present invention may be much more energy efficient than existing plant growth chamber, since the heat exchanger allows heat to be transferred from places where the heat is not needed to places where the heat can be used, therefore allowing heat energy to be recycled within the plant growth chamber to reduce wasted heat energy, minimise energy consumption and reduce noise (since cooling fans do not need to run so fast to get rid of waste heat).
  • the solid state heat pump may transfer heat between the fluid volume and the interior region of the plant growth chamber for heating and/or cooling the interior region, preferably including the plant growth region.
  • the heat exchanger may allow energy to be recovered from outlet gas (that is, the exhaust gas expelled from the plant growth chamber) which may then be used for heating and/or cooling other parts of the interior region, for example, the plant growth region.
  • the heat exchanger may also transfer heat between ambient air from outside the plant growth chamber that is drawn into the fluid volume and the interior region (for example, the plant growth region), acting as an energy efficient air source heat pump (for example, allowing heat to be extracted from the ambient air drawn into the fluid volume when heating the plant growth region above the ambient air temperature).
  • the heat exchanger may allow waste energy to be recovered from dehumidification, for example, from energy extracted from the air when cooling the air as part of the dehumidification process.
  • the plant growth chamber may further comprise a control loop configured to control the solid state heat pump in order to achieve a desired temperature in the interior region, such as the plant growth region.
  • the same, or a different, control loop may be configured to control the solid state heat pump, and optionally a humidifier, in order to achieve a desired humidity in the interior region, such as the plant growth region.
  • a control loop may comprise an algorithm employing one or more of: a proportional, an integral and a derivative term.
  • a control loop may control the power and/or polarity of the solid state heat pump to control the transfer of heat between the fluid volume and the interior region as required for heating and/or cooling the interior region, such as the plant growth region.
  • Measurements of the environmental conditions may be used as a feedback to a control loop.
  • measurements of the temperature, humidity and pressure of the interior region such as, the plant growth region and/or the inlet gas.
  • the measurements may be made using one or more sensors, such as individual temperature, humidity and pressure sensors, or a single sensor measuring temperature, humidity and pressure, or some other combination.
  • One or more sensors may be located in the interior region.
  • a sensor may be located in the plant growth region (for example, to measure how close the environmental conditions in the plant growth region are to a desired environmental condition, such as one or more of: temperature, humidity and carbon dioxide level).
  • a sensor may be located adjacent to the gas inlet (for example, to measure one or more of the temperature, humidity and pressure of the inlet gas to determine adjustments required to the temperature and/or humidity of the inlet gas to allow the plant growth region to reach the desired temperature and/or humidity).
  • a control loop particularly one employing one or more of a proportional, an integral and a derivative term can provide much smoother control of temperature than a simple thermostat, preventing or at least greatly reducing temperature fluctuations.
  • a control loop is not suited to existing compressor-based plant growth chambers which have moving parts that cannot be turned on and off quickly enough for precise control.
  • a solid state heat pump has no moving parts and the power to the solid state heat pump can be pulsed 10, 100, or even 1000 times per second, or controlled proportionally by varying the input current in an analogue fashion providing finely grained control over temperature that avoids or at least reduces temperature fluctuations.
  • the plant growth chamber may comprise a plurality of heat exchangers.
  • the plant growth chamber may comprise a gas inlet heat exchanger arranged adjacent to a gas inlet to control the temperature and/or humidity of the inlet gas.
  • the plant growth chamber may comprise a gas outlet heat exchanger arranged adjacent to a gas outlet (or exhaust) to extract waste heat energy from the outlet gas which may be reused in heating and/or cooling the interior region, such as the plant growth region.
  • the plant growth chamber may comprise a plant growth region heat exchanger arranged adjacent to the plant growth region, for heating and/or cooling the plant growth region.
  • the plant growth chamber may further comprise a gas inlet configured to deliver gas to the interior region.
  • the gas may comprise air (for example, ambient air from outside the plant growth chamber) or another gas or mixture of gases.
  • the gas may comprise an enrichment gas (such as carbon dioxide) to influence plant growth.
  • a gas inlet heat exchanger may be arranged adjacent to the gas inlet.
  • the gas inlet heat exchanger may comprise a solid state heat pump configured to transfer heat between the inlet gas and a fluid volume of the gas inlet heat exchanger for heating and/or cooling the inlet gas.
  • the gas inlet heat exchanger provides a compact way to control the temperature and/or humidity of the inlet gas, and provides a way to recycle any waste heat from dehumidification for heating and/or cooling the interior region (such as the plant growth region).
  • the plant growth chamber may further comprise a humidifier to increase the humidity of the gas in the interior region (such as the plant growth region) to a desired humidity.
  • the humidifier may be arranged adjacent to the gas inlet to increase the humidity of the inlet gas.
  • the humidifier may comprise ultrasonic water vaporisation, spray, nozzle, capillary wick, or other suitable humidification apparatus.
  • the plant growth chamber may further comprise a dehumidifier to decrease the humidity of the gas in the interior region (such as the plant growth region) to a desired humidity.
  • the dehumidifer may be arranged adjacent to the gas inlet to decrease the humidity of the inlet gas.
  • the dehumidifer may comprise the heat exchanger, that is to say, the heat exchanger may also act as the dehumidifier.
  • the dehumidifier may comprise a desiccant wheel.
  • the desiccant wheel may intercept the inlet gas, and moisture in the inlet gas may be absorbed by the desiccant wheel to reduce the humidity of the inlet gas.
  • the desiccant wheel may intercept (for example, pass through) a dry gas stream (such as the outlet gas stream from the adjacent gas inlet heat exchanger) which dries the desiccant to regenerate the desiccant.
  • the gas inlet heat exchanger may cool the inlet gas to a temperature below a dew point of the inlet gas (or to a temperature below a dew point for a desired humidity, such as a desired humidity in the plant growth region). This will condense water vapour from the inlet gas to generate inlet gas of a desired humidity.
  • the gas inlet heat exchanger may be configured to recover the heat energy extracted during cooling the inlet gas as part of dehumidification.
  • the gas inlet heat exchanger may transfer the heat energy extracted during cooling the inlet gas to the fluid volume. The heat energy recovered from dehumidification may be used for heating the interior region.
  • the gas inlet heat exchanger may further comprise a first thermally-conductive wall in thermal contact or thermally coupled with the inlet gas.
  • a first solid state heat pump may be thermally coupled to the first thermally-conductive wall.
  • the first solid state heat pump may be configured to transfer heat generated by dehumidifying the inlet gas to the fluid volume of the gas inlet heat exchanger.
  • a second thermally-conductive wall may be in thermal contact or thermally coupled with an interior region, such as the plant growth region.
  • a second solid state heat pump may be thermally coupled to the second thermally- conductive wall.
  • the second solid state heat pump may be configured to transfer heat from the fluid volume of the gas inlet heat exchanger to the interior region, such as the plant growth region.
  • the plant growth chamber may further comprise a gas outlet configured to remove gas from the interior region (for example, to outside the plant growth chamber).
  • a gas outlet heat exchanger may be arranged adjacent to the gas outlet.
  • the gas outlet heat exchanger may comprise a solid state heat pump configured to transfer heat between the outlet gas and a fluid volume of the gas outlet heat exchanger for recovering heat energy from the outlet gas which would otherwise be wasted when exhausted outside the plant growth chamber.
  • any of the heat exchangers may comprise a thermally-conductive wall in thermal contact or thermally coupled with the interior region.
  • the thermally-conductive walls may form part of a heat exchanger housing which separates the fluid volume from the interior region and may assist in transferring heat between the fluid volume and the interior region.
  • the solid state heat pump may be thermally coupled to the thermally-conductive wall.
  • One or more of the thermally-conductive walls may comprises a heatsink.
  • Such heatsinks increase the surface area of the thermally-conductive walls and therefore improve thermal transfer efficiency between the thermally-conductive walls and the surrounding gas.
  • the heatsinks may be aligned with the solid state heat pumps to further improve thermal transfer efficiency.
  • the gas inlet heat exchanger may have heatsinks coupled to the thermally-conductive wall adjacent to the gas inlet to improve thermal transfer efficiency between the inlet gas and its fluid volume.
  • the gas outlet heat exchanger may have heatsinks coupled to its thermally-conductive wall adjacent to the gas outlet, to improve thermal transfer efficiency between the outlet gas and its fluid volume.
  • the interior region may be filled with gas.
  • Gas to fill the interior region may be provided from the gas inlet.
  • the gas may comprise ambient air from outside the plant growth chamber. Additionally, or alternatively, the gas may comprise another gas or mixture of gases.
  • the gas may comprise an enrichment gas (such as carbon dioxide) that provides an enriched environment that influences plant growth.
  • the plant growth chamber may comprise a gas moving device (such as a fan or blower) for moving gas around the interior region to improve thermal transfer and even temperature distribution by encouraging the circulation of gas around the interior region.
  • the gas moving device may be located in the plant growth region, to improve the temperature distribution in particular around the plant growth region.
  • the gas moving device may be fixed to, or behind, the ceiling or side surfaces of the plant growth region, with an appropriate grille or aperture to allow gas flow as necessary.
  • the gas moving device may be coupled to a heatsink attached to a thermally-conductive wall facing the plant growth region, such as the thermally-conductive wall of the gas outlet heat exchanger which faces the plant growth region.
  • the heatsink may improve thermal transfer efficiency between the fluid volume of the gas outlet heat exchanger and the plant growth region.
  • a first surface of the solid state heat pump may be coupled to the thermally-conductive wall in thermal contact or thermally coupled with the interior region, such as the plant growth region.
  • a second surface of the solid state heat pump may be coupled to a thermally-conductive plate in thermal contact or thermally coupled with the fluid volume.
  • the thermally-conductive wall and thermally-conductive plate may form a sandwich with the solid state heat pump in between, which may protect the solid state heat pump from the fluid of the fluid volume.
  • Space between the thermally-conductive wall and the thermally-conductive plate may be insulated, to improve thermal separation between the interior region and the fluid volume and therefore improve energy efficiency.
  • the heat exchanger may further comprise a first thermally-conductive wall with a first solid state heat pump thermally coupled to the first thermally-conductive wall.
  • the heat exchanger may further comprise a second thermally-conductive wall with a second solid state heat pump thermally coupled to the second thermally-conductive wall.
  • the first and second thermally-conductive walls may both be in thermal contact or thermally coupled with the interior region.
  • the first thermally-conductive wall may be in thermal contact or thermally coupled with a plant growth region for transferring heat between the fluid volume and the plant growth region.
  • the second thermally-conductive wall may be in thermal contact or thermally coupled with a region adjacent a gas inlet configured to deliver gas to the interior region in which case the second thermally-conductive wall is configured to transfer heat between the fluid volume and the inlet gas.
  • the second thermally-conductive wall may be in thermal contact or thermally coupled with a region adjacent a gas outlet to remove gas from the interior region, in which case the second thermally-conductive wall is configured to recover heat energy from the outlet gas.
  • One or more thermal bridges may thermally couple first and second thermally-conductive plates.
  • the first and second thermally-conductive plates may be thermally coupled to the solid state heat pumps adjacent to the fluid volume.
  • the thermal bridges may improve thermal transfer efficiency as compared with thermal transfer solely through the fluid volume.
  • the fluid volume may further comprise a fluid inlet and a fluid outlet.
  • the fluid inlet may be configured to draw fluid from outside the plant growth chamber into the fluid volume.
  • the fluid outlet may be configured to remove fluid from the volume to a region outside the plant growth chamber.
  • the solid state heat pump may be configured to transfer heat energy between the fluid and the interior region.
  • the fluid may be a gas, such as ambient air from outside the plant growth chamber, which is cheap and readily available. Using a gas may only require simple fans, rather than complicated and more expensive pumps.
  • the fluid may be a liquid, which has improved heat capacity and therefore improves thermal transfer efficiency. Using a liquid may also reduce noise.
  • the plant growth chamber may further comprise one or more lights for providing light to the plant growth region.
  • the lights may be fixed around the plant growth region, for example, mounted to or below the ceiling or sides of the plant growth region.
  • the lights may comprise light emitting diodes which reduce waste heat energy transferred into the interior region.
  • the lights may be thermally coupled to the heat exchanger, which may help to remove waste heat generated by the lights from the interior region and may allow the waste heat to be recycled for heating and/or cooling the interior region.
  • the one or more lights may provide photosynthetically active radiation (such as radiation between 400 nm and 700 nm), and/or photobiologically active radiation (such as radiation between 280 nm and 800 nm) to modify plant growth and development (including primary and secondary metabolite production).
  • the one or more lights may provide photosynthetically and/or photobiologically active radiation in order to assess plant or plant cell status, quality, metabolite production or other traits (for example, using a hyperspectral imaging camera).
  • the one or more lights may also provide radiation outside the range of wavelengths that are photobiologically active to assess plant or plant cell status, quality, metabolite production, or other traits (for example, using a hyperspectral camera) without influencing the growth and development (or primary and secondary metabolite production) of the plant or plant cell itself.
  • the solid state heat pump may be a thermoelectric heat pump, or any other solid state heat pump known to the skilled person, (such as a magnetic or thermoacoustic heat pump), transferring heat via conduction or convection.
  • Figure 1 is a three-dimensional view of a plant growth chamber according to an embodiment of the present invention.
  • Figure 2 illustrates a side view of the plant growth chamber of Figure 1 with side panels removed to show the internal arrangement of the plant growth chamber and the heat exchangers;
  • Figure 3 illustrates a top view of a heat exchanger in the top section of the plant growth chamber
  • Figure 4A is a side view of a portion of the bottom section of the plant growth chamber showing an optional desiccant wheel
  • Figure 4B is a three-dimensional exploded view of the bottom section of the plant growth chamber showing the optional desiccant wheel.
  • Figure 5 illustrates a control system for controlling the temperature and humidity in the plant growth chamber of Figure 1.
  • FIG. 1 illustrates a plant growth chamber 100.
  • the plant growth chamber 100 may be used for growing plants or plant cells in soil, soilless culture, or sterile culture, under controlled environmental conditions.
  • the plant growth chamber 100 has a housing 110 with a door 112 which, when open, gives access to a plant growth region 120 where one or more plants 121 or plant cells can be located and, when closed, isolates the plant growth region 120 from the environment outside the plant growth chamber 100, so that the environmental conditions (such as temperature, humidity and lighting) in the plant growth region 120 can be controlled as required by experiments that are being conducted into the growth of the plants 121 or plant cells.
  • the environmental conditions such as temperature, humidity and lighting
  • Lighting is provided by one or more lights 114 located around the plant growth region 120.
  • the lights 114 are located on the roof of the plant growth region 120, although the lights 114 could be located on the sides of the plant growth region 120 instead.
  • the lights 114 may be light emitting diodes to reduce unnecessary heat load into the plant growth chamber 100.
  • the plant growth chamber 100 has a bottom section 116 and a top section 118 which house heating and cooling equipment for controlling the temperature in the plant growth region 120, as well as equipment for adjusting the humidity in the plant growth region 120.
  • the heating and cooling equipment is compact and lightweight compared to existing plant growth chambers.
  • the plant growth chamber 100 is small and light enough to be stacked.
  • the plant growth chamber 100 has feet 108 on the bottom of the plant growth chamber 100 which mate with recesses or fixtures 109 on the top of another plant growth chamber 100, with the sides of the plant growth chamber 100 constructed such that they are suitable for taking the weight of one or more plant growth chambers 100 stacked on top.
  • Figures 2 and 3 illustrate the compact heating and cooling equipment in more detail. Specifically, Figure 2 illustrates a side view of the plant growth chamber 100 of Figure 1 with all of the side panels removed so that the configuration of the heating and cooling equipment can be seen in detail. Figure 3 illustrates a top view of a gas outlet heat exchanger 122b of the top section 118.
  • the bottom section 116 and the top section 118 of the plant growth chamber 100 each contain a heat exchanger 122.
  • Each heat exchanger 122 has an internal fluid volume 124 which is thermally separated from the interior of the plant growth chamber 100 by heat exchanger housing 126, which may be thermally insulated to prevent unwanted heat transfer.
  • the internal fluid volume 124 in each heat exchanger 122 is filled with a fluid, typically ambient air.
  • Air is drawn into the inlet 127 of each heat exchanger 122 from outside the plant growth chamber 100 using a fan 128 and expelled from the outlet 129 in that heat exchanger using a fan 128, allowing air to circulate through the internal fluid volume 124.
  • Each heat exchanger 122 has one or more solid state heat pumps 130, such as thermoelectric heat pumps.
  • each heat exchanger 122 has eight solid state heat pumps 130 (four coupled to the bottom of each heat exchanger 122 and four coupled to the top of each heat exchanger 122).
  • each heat exchanger 122 can have any number of solid state heat pumps 130 as required to achieve a desired level of heating and/or cooling.
  • the solid state heat pumps 130 transfer heat between the internal fluid volume 124 and the interior of the plant growth chamber 100 for heating and/or cooling the plant growth region 120.
  • the heat exchangers 122 allow energy to be recovered from outlet air 144 which can be used for heating and/or cooling the plant growth region 120.
  • the heat exchangers 122 may also transfer heat between the outside ambient air drawn into the internal fluid volume 124 and the plant growth region 120, acting as an energy efficient air source heat pump (for example, allowing heat to be extracted from the ambient air drawn into the internal fluid volume 124 when heating the plant growth region 100 above the ambient air temperature). Also, the heat exchangers 122 allow waste energy to be recovered from dehumidification.
  • each heat exchanger housing 126 are formed from a sandwich comprising a thermally-conductive wall 136 on the outer surface of the heat exchanger 122 which faces the interior of the plant growth chamber 100 and a thermally- conductive plate 137 on the inner surface of the heat exchanger 122 facing the internal fluid volume 124.
  • Solid state heat pumps 130 are coupled between the thermally- conductive walls 136 and the thermally-conductive plates 137.
  • the thermally-conductive walls 136 assist in transferring heat between the inside of the plant growth chamber 100 and the solid state heat pumps 130.
  • the thermally conductive plates 137 assist in transferring heat between the solid state heat pumps 130 and the internal fluid volume 124.
  • Insulation may be provided between a thermally-conductive wall 136 and its respective thermally-conductive plate 137, to improve thermal separation between the interior of the plant growth chamber 100 and the fluid-filled volume 124 which can improve energy efficiency.
  • the thermally-conductive wall 136 and the heatsinks 150, and the thermally-conductive plates 137 and the thermal bridges 156, may be constructed from a single piece of material, for example a milled or extruded section of aluminium.
  • a fan 131 draws fresh air from outside the plant growth chamber 100 into the gas inlet 132 in the bottom section 116 behind grille 119a.
  • the bottom section 116 may adjust the humidity of inlet air 134 to a desired humidity for the plants 121 or plant cells, and may heat or cool the inlet air 134 to the desired temperature for the plants 121. In this way, the bottom section 116 provides a compact way to control both the temperature and humidity of the inlet air 134.
  • the gas inlet heat exchanger 122a in the bottom section 116 has a thermally-conductive wall 136a on the bottom of the heat exchanger 122a, adjacent to the gas inlet 132.
  • Solid state heat pumps 130a are thermally coupled between the thermally-conductive wall 136a and thermally-conductive plate 137a which together transfer heat between the inlet air 134 and the internal fluid volume 124a.
  • the plants 121 or plant cells sit on a perforated floor 111 of the plant growth region 120.
  • the perforated floor 111 is made from a sheet of material with an array of holes (for example, being formed of a grid or mesh) which supports the plants 121 while allowing air to pass through.
  • Thermally-conductive wall 136b on the top of the heat exchanger 122a is offset below the perforated floor 111 to form a channel between the perforated floor 111 and the thermally-conductive wall 136b which allows inlet air 134 to pass over the thermally-conductive wall 136b as it passes through the perforated floor 111.
  • Solid state heat pumps 130b are thermally coupled to the thermally-conductive wall 136b and thermally conductive plate 137b which together transfer heat between the internal fluid volume 124a and the inlet air 134 as it passes over the thermally-conductive wall 136b on its way through the perforated floor 111. If the inlet air 134 is too cold (for example, colder than the desired temperature for the plant growth region 120), the inlet air 134 may be heated by transferring heat from the fluid volume 124a to the inlet air 134 using the solid state heat pumps 130a, and optionally solid state heat pumps 130b if further heating is required.
  • the inlet air 134 may be cooled by transferring heat from the inlet air 134 to the fluid volume 124a using the solid state heat pumps 130a, and optionally solid state heat pumps 130b if further cooling is required.
  • the humidifier 135 in the bottom section 116 may be controlled to increase the humidity of the inlet air 134.
  • the humidifier 135 may use ultrasonic water vaporisation, spray nozzle, capillary wick, or other suitable apparatus.
  • the bottom section 116 may dehumidify the inlet air 134.
  • the inlet air 134 is cooled below the dew point for the desired humidity by the solid state heat pumps 130a, with the waste heat from cooling the inlet air 134 being transferred to the internal fluid volume 124a. Cooling the inlet air 134 below the dew point causes water vapour to condense out of the inlet air 134.
  • the condensed water vapour may be collected in a tray in the base of the plant growth chamber 100 which may be emptied at the end of an experiment, or flow into channels in the base of the plant growth chamber 100 and through an outlet connected to a waste container or drain.
  • the dehumidified inlet air may be heated by transferring heat from the fluid volume 124a to the dehumidified inlet air using the solid state heat pumps 130b.
  • the dehumidified inlet air may be further cooled by transferring heat from the dehumidified inlet air to the fluid volume 124a using the solid state heat pumps 130b.
  • the gas inlet heat exchanger 122a provides a possible way to recycle heat energy extracted from the inlet air 134 when cooling the inlet air 134 during dehumidification.
  • the heat energy is transferred to the internal fluid volume 124a by solid state heat pumps 130a.
  • solid state heat pumps 130b can transfer heat energy from the internal fluid volume 124a, including the heat harvested when cooling the inlet air 134 as part of the dehumidification process thereby recycling at least some of the energy used in dehumidification.
  • the top section 118 has an air outlet 142 behind grille 119b on the front of the housing 110.
  • a fan 141 pulls stale air from the plant growth region 120 and expels it though air outlet 142 outside the plant growth chamber 100.
  • the gas outlet heat exchanger 122b in the top section 118 allows energy to be recovered from the outlet air 144 to reduce energy consumption when heating and cooling the plant growth region 120.
  • the solid state heat pumps 130d recover heat energy from the outlet air 144.
  • the outlet air 144 cools thermally-conductive wall 136d, creating a temperature gradient between solid state heat pumps 130d and 130c which improves the efficiency with which solid state heat pump 130c transfers heat from the plant growth region 120.
  • the plant growth chamber 100 may have thermal bridges 156 aligned with the solid state heat pumps 130 which connect the thermally-conductive plates 137 to improve thermal transfer efficiency as compared with thermal transfer solely through the internal fluid volume 124.
  • the thermally-conductive walls 136 may have heatsinks 150 to increase the surface area of the thermally-conductive walls 136 and therefore improve thermal transfer efficiency between the thermally-conductive walls 136 and the surrounding air.
  • the heatsinks 150 may be aligned with the solid state heat pumps 130 to further improve thermal transfer efficiency.
  • the gas inlet heat exchanger 122a in the bottom section 116 may have heatsinks 150 coupled to thermally-conductive wall 136a to improve thermal transfer efficiency between the inlet air 134 and the internal fluid volume 124a.
  • the gas outlet heat exchanger 122b in the top section 116 may have heatsinks 150 coupled to thermally- conductive wall 136d to improve thermal transfer efficiency between the outlet air 144 and the internal fluid volume 124b.
  • Thermally-conductive walls 136 and associated heatsinks 150 with them may be constructed as a single piece of material, for example a milled or extruded section of aluminium.
  • the plant growth chamber 100 may have one or more fans 154 to improve thermal transfer and even temperature distribution by encouraging the circulation of air around plant growth region 120.
  • the fans 154 may be adjacent to a heatsink 152 attached to thermally- conductive wall 136c facing the plant growth region 120.
  • the heatsink 152 may improve thermal transfer efficiency between thermally-conductive wall 136c and plant growth region 120 and the fans 154 may improve thermal transfer efficiency between the surrounding gas and the heatsink 152.
  • An array of lights 114 is fixed beneath the top region 118 to illuminate the plant growth region 120.
  • the array of lights 114 may provide visible light to enable an operator to see inside the plant growth chamber 100.
  • the array of lights 114 may provide photosynthetically active radiation (such as radiation between 400 nm and 700 nm), and/or photobiologically active radiation (such as radiation between 280 nm and 800 nm) to modify the growth and development (including primary and secondary metabolite production) of plant 121 or plant cells.
  • the array of lights 114 may provide photosynthetically and/or photobiologically active radiation in order to assess the status, quality, metabolite production or other traits of plant 121 or plant cells (for example, using a hyperspectral imaging camera).
  • the array of lights 114 may provide radiation outside of the range of wavelengths that are photobiologically active to assess plant 121 or plant cell status, quality, metabolite production, or other traits (for example, using a hyperspectral camera) without influencing the growth and development (or primary and secondary metabolite production) of the plant 121 or plant cells.
  • the lights 114 are thermally coupled to the thermally-conductive wall 136c which allows at least some of the waste heat produced by the lights 114 to be removed from the plant growth region 120, reducing or eliminating warming of the plant growth region 120 by the lights, and recovering waste heat energy from the lights 114 to reduce energy consumption in heating and/or cooling the plant growth region 120.
  • Light emitting diodes may be used to reduce the amount of waste heat produced.
  • Figures 4A and 4B illustrate how an optional desiccant wheel assembly 160 may be incorporated into plant growth chamber 100 for dehumidifying the inlet air 132 in addition to, or instead of, using the gas inlet heat exchanger 122a for dehumidifying the inlet air 132.
  • Figure 4A shows an expanded side view of a portion of the gas inlet heat exchanger 122a in bottom section 116, showing the desiccant wheel assembly 160 in position.
  • Figure 4B is an exploded three-dimensional view of the bottom section 116 of plant growth chamber 100 to illustrate the position of the desiccant wheel assembly 160 with respect to air inlet 132 and outlet 129 in the gas inlet heat exchanger 122a.
  • grille 119a is not shown in Figure 4B and the desiccant wheel assembly 160 is shown offset from the front panel of bottom section 116. When assembled, the desiccant wheel assembly 160 would be placed in close proximity to the front panel of bottom section 116.
  • the desiccant wheel assembly 160 includes a housing 161 which encloses a rotating desiccant wheel 163 (illustrated as a dashed cylinder in Figure 4B).
  • the desiccant wheel 163 is a disc coated with desiccant material (such as silica gel) which absorbs moisture.
  • the desiccant wheel housing 161 has a first opening 162 aligned with air inlet 132 (as shown by dashed lines in Figure 4B). Air from outside the plant growth chamber 100 usually contains moisture.
  • the desiccant wheel housing 161 has a second opening 164 aligned with the outlet 129 of gas inlet heat exchanger 122a (as shown by dashed lines in Figure 4B) so that the desiccant wheel 163 intercepts air passing through outlet 129.
  • the desiccant wheel 163 continuously rotates into the path of the intercepted air to dry the wet desiccant material, for example, using waste heat generated by operation of gas inlet heat exchanger 122a.
  • FIG. 5 shows a control system 200 for controlling the temperature and humidity in the plant growth region 120.
  • the control system 200 has a microcontroller 210 with a wireless interface 220 in communication with a user control device 230, such as an app running on a user's smartphone or a web browser, either directly, or indirectly via a backend server and internet connection.
  • a user control device 230 such as an app running on a user's smartphone or a web browser, either directly, or indirectly via a backend server and internet connection.
  • the user sets a temperature and humidity set point using the user control device 230.
  • a sensor 139 in the plant growth region 120 measures the humidity, temperature and pressure in the plant growth region 120.
  • a sensor 138 in bottom section 116 measures the humidity, temperature and pressure of inlet air 134.
  • the microcontroller 210 executes a control loop (such as a proportional integral differential control loop) using the humidity, temperature and pressure measured by sensors 138 and 139 as feedback, to control the power to the solid state heat pumps 130, fans 128a and 128c, 131 and 141 and humidifier 135 to drive the temperature and humidity in the plant growth region 120 towards the temperature and humidity set points and then maintain the temperature and humidity in the plant growth region 120 around those temperature and humidity set points.
  • a control loop such as a proportional integral differential control loop
  • any thermally-conductive walls 136 and thermally-conductive plates 137 not involved in dehumidification are kept at a temperature above that of the dew-point of the air in thermal contact with them, to prevent unwanted condensation forming.
  • a minimum wall/plate temperature is calculated. This minimum wall/plate temperature is provided as feedback to the control loops controlling the solid state heat pumps 130 and the speed of the fans 128a and 128c, 131 and 141 to keep the thermally-conductive walls 136 and thermally-conductive plates 137 above the minimum wall/plate temperature to prevent unwanted condensation forming.
  • the operation of a control loop may be illustrated with the following example.
  • the microcontroller 210 runs a master control loop which calculates a dew point temperature for a humidity level based on the humidity set point, the humidity measured in the plant growth region 120 by sensor 139 and the humidity of the inlet air 134 measured by sensor 138. For example, if the humidity in the plant growth region 120 is too high, the microcontroller 210 calculates a dew point temperature for a desired humidity level below the humidity measured in the plant growth region 120.
  • a solid state heat pump 130a control loop controls the power to the solid state heat pump 130a so that the temperature of thermally-conductive plate 136a (measured by sensors fixed to, or embedded in, the surface of the thermally-conductive plate 136a) is at or around the dew point temperature, to reduce the inlet air 134 to the desired humidity level.
  • the master control loop calculates a heating/cooling temperature based on the temperature measured in the plant growth region 120 and the temperature of the inlet air 134 (or where the inlet air 134 has been dehumidified based on the temperature of the dehumidified inlet air) and a solid state heat pump 130b control loop controls the power to solid state heat pumps 130b so that the temperature of the thermally-conductive plate 136b (measured by sensors fixed to, or embedded in, the surface of the thermally- conductive plate 136b) is at or around the heating/cooling temperature and a solid state heat pump 130c control loop controls the power to solid state heat pumps 130c so that the temperature of the thermally-conductive plate 136c (measured by sensors fixed to, or embedded in, the surface of the thermally-conductive plate 136c) is at or around the heating/cooling temperature.
  • the master control loop calculates a heating temperature above the temperature of the plant growth region 120.
  • the solid state heat pump 130b control loop controls the power to the solid state heat pumps 130b so that the temperature of thermally-conductive plate 136b (measured by sensors fixed to, or embedded in, the surface of the thermally-conductive plate 136b) is at or around the heating temperature.
  • the solid state heat pump 130c control loop also controls the power to the solid state heat pumps 130c so that the temperature of thermally-conductive plate 136c (measured by sensors fixed to, or embedded in, the surface of the thermally-conductive plate 136c) is at or around the heating temperature.
  • the master control loop calculates a dew point temperature for a humidity level based on the humidity set point, humidity measured in the plant growth region 120 by sensor 139 and the humidity of the inlet air 134 measured by sensor 138.
  • a solid state heat pump 130d control loop is set to control the power to solid state heat pump 130d to keep thermally-conductive plate 136d above the dew point temperature (measured by sensors fixed to, or embedded in, the surface of the thermally-conductive plate 136d) to prevent condensation forming on thermally-conductive plate 136d.
  • the solid state heat pump 130d control loop also adjusts the power and polarity to solid state heat pump 130d, to maintain thermally-conductive wall 137d at or around the ambient temperature of the air outside the plant growth chamber 100 to recover waste heat energy from the outlet air 144 or to improve the efficiency with which solid state heat pump 130c transfers heat energy with the plant growth region 120.
  • the speed of fans 131 and 141 control air flow through the plant growth region 120.
  • the speed of fans 131 and 141 may be controlled to minimise energy consumption (for example, by keeping the number of air changes to a minimum) and maintain a desired carbon dioxide level in the plant growth region 120.
  • the sensor 139 may include a carbon dioxide sensor which may be used as a feedback to a fan control loop which controls the speed of fans 131 and 141 to achieve carbon dioxide in the plant growth region 120 at or around the desired level.
  • the speed of fan 128a (which controls air flow through the internal fluid volume 124a) is controlled in proportion to the temperature of the inlet air 134 and the difference in temperature between thermally-conductive plates 137a and 137b (as measured by sensors fixed to, or embedded in, the surface of the thermally-conductive plates 137a and 137b), to maximise heat transfer between the internal fluid volume 124a and air in the plant growth chamber 100 and minimise noise from fan 128a and wear on fan 128a.
  • the speed of fan 128b (which controls air flow through the internal fluid volume 124b) is controlled in proportion to the temperature of the inlet air 134 and the difference in temperature between thermally-conductive plates 137c and 137d (as measured by sensors fixed to, or embedded in, the surface of the thermally-conductive plates 137c and 137d), to maximise heat transfer between the internal fluid volume 124b and air in the plant growth chamber 100 and minimise noise from fan 128b and wear on fan 128b.
  • the fluid volume 124 could be filled with a gas other than air, for example, a gas which provides improved heat capacity.
  • the fluid volume could be filled with a liquid, like water or antifreeze with the fans replaced with suitable equipment for transporting liquids, such as pumps.
  • a liquid may provide better thermal transfer efficiency than a gas, but at increased expense due to the costs associated with pumping and handling the liquid.
  • gas filling the interior of the plant growth chamber 100 is described as being ambient air from outside the plant growth chamber 100, the interior may be filled with another gas or mixture of gases in addition to, or instead of, air (such as an enrichment gas, like carbon dioxide, which provides an enriched environment that influences plant growth).
  • the gas or gases may be provided via gas inlet 132.
  • gas inlet 132 could be attached to a gas cylinder or gas manifold.
  • the solid state heat pumps 130 may be thermoelectric heat pumps, or any other kind of solid state heat pumps known to the skilled person, such as magnetic or thermoacoustic heat pumps.
  • the lights 114 are shows attached to thermally-conductive wall 136c.
  • the light 114 could instead be attached to thermally-conductive plate 137c, where the lights are better protected from damage, and where the lights would be more directly thermally connected with the internal fluid volume 124d such that waste heat generated by the lights 114 may be more efficiently extracted.
  • thermally-conductive wall 136c could have apertures, holes or perforations to allow light into the plant growth region 120 which may be covered with a transparent window or cover.
  • the sensors 138 and 139 have been described as single sensors incorporating humidity, temperature and pressure sensing. However, one or more of the humidity sensor, temperature sensor and pressure sensor could be provided as individual sensors.
  • the controls system 200 has been described as having a wireless communications interface, the communications interface could instead be wired.
  • the communications interface could instead be wired.
  • a user control device 230 such as a smart phone or webpage
  • the plant growth chamber 100 may have humidity and temperature set point controls on the plant growth chamber 100 (for example, as buttons or knobs attached to the housing).
  • any other air circulating device could be used additionally or alternatively, such as blowers.

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Environmental Sciences (AREA)
  • Cultivation Of Plants (AREA)
  • Greenhouses (AREA)

Abstract

Une chambre de croissance de plantes comporte une région intérieure, et un échangeur de chaleur. L'échangeur de chaleur présente un volume de fluide séparé de la région intérieure, et une pompe à chaleur à semi-conducteurs configurée pour transférer de la chaleur entre le volume de fluide et la région intérieure pour chauffer et/ou refroidir la région intérieure.
PCT/GB2019/052064 2018-07-23 2019-07-23 Chambre de croissance de plantes WO2020021253A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB2102206.6A GB2591623A (en) 2018-07-23 2019-07-23 Plant growth chamber

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GBGB1811965.1A GB201811965D0 (en) 2018-07-23 2018-07-23 Plant Growth Chamber
GB1811965.1 2018-07-23

Publications (1)

Publication Number Publication Date
WO2020021253A1 true WO2020021253A1 (fr) 2020-01-30

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ID=63364510

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Application Number Title Priority Date Filing Date
PCT/GB2019/052064 WO2020021253A1 (fr) 2018-07-23 2019-07-23 Chambre de croissance de plantes

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Country Link
GB (2) GB201811965D0 (fr)
WO (1) WO2020021253A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2022232916A1 (fr) * 2021-05-03 2022-11-10 Ferme D'hiver Technologies Inc. Système et procédé de gestion d'énergie dans des serres et fermes verticales combinées

Citations (5)

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Publication number Priority date Publication date Assignee Title
US6725598B2 (en) * 2001-07-05 2004-04-27 Ccs Inc. Plant cultivator and control system therefor
JP2005328733A (ja) * 2004-05-18 2005-12-02 Ccs Inc 除湿機構及び植物育成装置
EP2143320A1 (fr) * 2007-04-27 2010-01-13 Elm Inc. Appareil pour la germination et la croissance et dispositif pour la culture de végétaux
KR101354706B1 (ko) * 2013-02-25 2014-01-24 주식회사 경우 가정용 채소류 재배장치
US20160183477A1 (en) * 2014-12-31 2016-06-30 Cal-Comp Biotech Co., Ltd. Cultivating box for plants and cultivating method used by the cultivating box

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6725598B2 (en) * 2001-07-05 2004-04-27 Ccs Inc. Plant cultivator and control system therefor
JP2005328733A (ja) * 2004-05-18 2005-12-02 Ccs Inc 除湿機構及び植物育成装置
EP2143320A1 (fr) * 2007-04-27 2010-01-13 Elm Inc. Appareil pour la germination et la croissance et dispositif pour la culture de végétaux
KR101354706B1 (ko) * 2013-02-25 2014-01-24 주식회사 경우 가정용 채소류 재배장치
US20160183477A1 (en) * 2014-12-31 2016-06-30 Cal-Comp Biotech Co., Ltd. Cultivating box for plants and cultivating method used by the cultivating box

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2022232916A1 (fr) * 2021-05-03 2022-11-10 Ferme D'hiver Technologies Inc. Système et procédé de gestion d'énergie dans des serres et fermes verticales combinées

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GB202102206D0 (en) 2021-03-31
GB201811965D0 (en) 2018-09-05

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