Patent Application
20160010899
There is a need for reliable, cost-effective and cost-certain systems to control climate in an enclosed space. Provided herein are systems that facilitate control of temperature, specifically heating and cooling control, CO2 levels and electrical needs, all from a source of hydrocarbon fuel. Specific applications including rooms or buildings of an indoor agriculture facility where the climate is controlled to maximize plant growth and electrical needs are accommodated, all in a highly reliable, cost-effective, and environmentally friendly manner.
An efficient form of cooling for an indoor agricultural facility is a water chilled system. Those chiller plants are all run off electricity from the electric grid. The lights, of course, also run off electricity from the electric grid. The heating necessary is also often electric heat. This is now subject to demand rates and seasonal rates for electricity in some areas. This can significantly increase costs, especially during the summer when electricity demand on the grid is highest, often resulting in a corresponding increase in cost for cooling. This disadvantage may be avoided with a poly-generation agricultural plant, where everything is powered off hydrocarbon-fueled electrical generators. This also provides the capability of being completely disconnected from the power grid.
Greenhouses, the largest of indoor agricultural facilities, often suffer from the inability to properly control humidity, therefore providing prime conditions for many molds and other harmful organisms to grow. They also require supplemental lighting which must be powered from the electric grid. Often times, the largest of greenhouses are in very low population urban areas with poor power quality and frequent power outages. With a poly-generation agricultural plant, the humidity can be controlled with the simultaneous cooling and heating and the facility can also be completely disconnected from the grid, therefore providing the operator much better control over not only the environment the plants will be growing in, but also, avoiding power loss due to a failure in the electric grid.
For the highest production out of an indoor agricultural facility, CO2 enrichment of the air is commonplace. CO2 enrichment is currently only done via a controlled release of compressed CO2. This requires constant refilling of CO2 as storing large amounts of CO2 on site is not cost effective. This requires extra equipment and piping to provide CO2 enrichment throughout the facility. Accordingly, there is a need not only for supply of electricity, heating and cooling, but also for reliable CO2 control in a single system. The systems and processes provided herein are also useful for supplying a clean and constant supply of CO2 without additional equipment to maintain or install.
Co- and tri-generation are known in the art. For example, combined heat and power are advertised as being “more fuel efficient and environmentally beneficial than utility power and boiler heating.” See, capstoneturbine.com/prodsol/solutions/chp.asp. U.S. Pat. No. 6,446,385 describes a greenhouse system with co-generation power supply, heating and exhaust gas fertilization. U.S. Pat. No. 8,132,738 describes a device for heating, generating electric power, and cooling enclosed spaces. Each of those systems, however, are deficient in that they do not provide a reliable source of each of electricity, heating, cooling and CO2 to an indoor agricultural producing facility in a single integrated process.
Provided herein are systems and methods for controlling climate in an enclosed space, such as an indoor agricultural facility, in a reliable, cost-effective and environmentally friendly manner.
In an embodiment, a natural gas turbine or generator provides power for auxiliary equipment used in an indoor agricultural facility, such as lighting used for plant growth. The hot exhaust gases pass over an air to water heat exchanger to create hot water. This hot water is used to power an absorption chiller as well as provide heating in the indoor growing rooms. The absorption chiller simultaneously provides cooling for the large amount of lighting necessary in the indoor growing rooms. A portion of the exhaust gases are passed through a filter and into the indoor growing rooms providing CO2 enrichment of the air for the plants in order to increase the production of the plants.
In this manner, provided is combined cooling, heating, power, and CO2 enrichment for indoor agricultural facilities and may be referred herein as a poly-generation plant for an agricultural facility. The systems provide the best controlled environment for a plant to grow under while greatly reducing the operating costs, and greatly reducing CO2 emissions, also known in the art as greenhouse gas emissions.
A natural gas generator or a series of generators are installed as the primary power source for the facility. The exhaust gases are sent through a conduit into an air to water heat exchanger wherein heat in the exhaust gases is transferred to a water or water-glycol mixture. This hot brine solution is pumped first to an absorption chiller. The absorption chiller is considered an indirect fired absorption chiller as the primary source of heat (the burning of natural gas) is not directly heating the refrigerant. After the brine solution passes through the absorption chiller, it is pumped into a reservoir to complete the loop. From that same reservoir, hot water is provided into the growing rooms to provide heating when the lights are off and is controlled so as to match the cooling requirements for dehumidification or the heating requirements, as necessary.
The absorption chiller exhausts heat to a cooling tower or a dry cooler and provides chilled water to fan coil units in the growing rooms to provide cooling to the room as the lights provide a large amount of heat.
The hot water in the hot water loop as well as the chilled water in the chilled water loop may be used in combination with each other to provide complete climate control of the growing rooms.
After the hot exhaust gas passes through the air to water heat exchanger for the hot water loop, a portion of those gasses are provided in a conduit and through an air filter and into the growing rooms to provide CO2 enrichment in order to stimulate the plants and increase agricultural production. This conduit may have a shutoff valve operably connected to a CO2 sensor in the growing rooms to close when the CO2 level in the growing rooms or enclosed space is too high or above a user-selected threshold.
A benefit of this natural gas power is that natural gas can be bought on a contract for a long period of time. Therefore, the operating costs of the agricultural plant can be kept at a constant value over a long period of time. Furthermore, this minimizes or avoids demand rates for electricity, further reducing operating costs. On top of all this, the combustion of natural gas is considered very clean. It is one of the cleanest burning fuels and, compared to coal power generation, the reduction of greenhouse gas emissions can be orders of magnitude less without sacrificing the ability to achieve the same growth results. This complete system of quad-generation, cooling, heating, power, and CO2, can provide efficiency increases of the natural gas generator from around 35% to as high as 75%. Even higher efficiencies are achieved by biogas generation from waste plant matter with attendant natural gas provided as a fuel to the generator.
In an embodiment, the invention is a system for controlling climate in an enclosed space. The system may have a hydrocarbon-fueled electrical power generator and an electrical power line for conducting electricity from the hydrocarbon-fueled electrical power generator to the enclosed space or to an electrically powered component of the system. An exhaust outlet conduit is operably connected to the electrical power generator for transporting a high temperature exhaust gas produced by the electrical power generator, such as by the combustion of the hydrocarbon fuel to generate electricity. A heat exchanger is thermally connected to the exhaust outlet conduit. Various fluid loops are provided to provide efficient thermal transfer and controls. For example, a recirculating thermal fluid loop is thermally connected to the heat exchanger, wherein high temperature exhaust gas introduced to the heat exchanger by the exhaust outlet conduit heats a recirculating thermal fluid in the recirculating thermal fluid loop. An absorption chiller is thermally connected to the recirculating thermal fluid loop, wherein the heated recirculating thermal fluid powers the absorption chiller. A heated thermal fluid loop is in thermal contact with the recirculating thermal fluid loop at a first end and in thermal contact with the enclosed space at a second end to provide a supply of a heated thermal fluid in thermal contact with the enclosed space and thereby heating control of the enclosed space. In this context, thermal contact is used broadly and may refer to a heated thermal fluid loop that is an integral part of the recirculating thermal fluid loop (e.g., the same thermal fluids in one loop is introduced to the other loop) or that is a distinct loop with physically separated thermal fluids between the two loops (e.g., no mixing between the thermal fluids in the two loops). A chilled thermal fluid loop is in thermal contact with the absorption chiller at a first end and in thermal contact with the enclosed space at a second end to provide a supply of chilled thermal fluid in thermal contact with the enclosed space and thereby cooling control of said enclosed space. The chilled thermal fluid loop first end may correspond to an outlet chilled line from the absorption chiller. In this manner, electricity, cooling and heating is provided to the enclosed space. A fourth input control, CO2 concentration, is provided by a downstream exhaust outlet conduit connected to the heat exchanger that removes high temperature exhaust gas from the heat exchanger. A CO2 conduit having a first end fluidically connected to the downstream exhaust outlet conduit and a second end fluidically connected to the enclosed space provides CO2 to the enclosed space. In the most fundamental form, the CO2 conduit may simply correspond to the exhaust outlet conduit, with desired filters, scrubbers or the like to provide a relatively pure source of CO2 gas with unwanted chemical species removed.
In an embodiment, any of the enclosed spaces provided herein may correspond to an indoor agricultural producing facility, such as a warehouse or a greenhouse. Depending on the size of the enclosed space, a generator size is selected, with more powerful generators generally corresponding to larger size enclosed spaces. One advantage of the systems and methods provided herein is if an enclosed space is too large for a single generator to supply sufficient climate control, multiple generators may be employed. The multiple generators may be incorporated together so as to provide climate control by one main system. Alternatively, the multiple generators may each be connected to their own systems so as to provide independent sources of climate control.
In an aspect, the hydrocarbon fueled electrical power generator is selected from the group consisting of a genset; a natural gas turbine; and a diesel generator. “Genset” is used herein to refer to a combination of a combustion engine and generator used to generate electricity.
In an embodiment, an artificial light source is electrically connected to the electrical power line, wherein the artificial light source stimulates growth of a plant in the enclosed space. In an aspect, the electrical power line may be connected to any number of electricity-requiring components in the system. Examples of components include, but are not limited to, an air-cooled chiller, a pump, a sensor (e.g., flow, pressure, temperature, humidity, CO2, etc.) a controller, a flow-valve, a light, a blower, a fan, and any combination thereof.
In an aspect, a heated thermal fluid reservoir is fluidically connected to the recirculating thermal fluid loop and fluidically or thermally connected to the heated thermal fluid loop, wherein the heated thermal fluid reservoir stores a volume of heated thermal fluid. The heated thermal reservoir may have an inlet and the absorption chiller may have a heated thermal fluid outlet, wherein the heated thermal reservoir inlet is fluidically connected to the absorption chiller heated thermal fluid outlet. The heated thermal reservoir may have an outlet that is fluidically connected to the heat exchanger. The absorption chiller may be fluidically connected to each of the heat exchanger and the heated thermal reservoir. This is one embodiment of a thermal fluid loop formed from three distinct components; a heat exchanger, an absorption chiller, and a thermal fluid reservoir.
The fluidic connection of any of the systems provided herein may comprise a conduit or a pipe, along with any fittings or connectors as desired to avoid leaks.
In an aspect, the recirculating heated water loop comprises: a heated thermal fluid supply line having a first end and a second end, wherein the heated thermal fluid supply line first end is thermally connected to the heated thermal fluid reservoir and the heated thermal fluid supply line second end is thermally connected to the enclosed space for supplying heat to the enclosed space; and a heated thermal fluid return line having a first end and a second end, wherein the first end is fluidically connected to the heated thermal fluid supply line and the second end is thermally or fluidically connected to the heated thermal fluid reservoir. The heated thermal fluid return line returns heated thermal fluid that has been cooled by the enclosed space to the hot water reservoir in an open loop configuration; or returns heated thermal fluid that has been cooled by the enclosed space for heating by the heater thermal fluid reservoir in a closed loop configuration. In an open loop configuration, the heated thermal fluid in the recirculating heated thermal fluid loop corresponds to the thermal fluid in the thermal reservoir, and may further then correspond to the thermal fluid contained in the recirculating thermal fluid loop.
In an aspect, the heated thermal fluid reservoir comprises a water tank having a volume that is greater than or equal to 10 gallons. In an aspect, the heated thermal fluid reservoir has a temperature that is greater than or equal to 100° F.
In an embodiment, the recirculating thermal fluid loop is a closed loop. In an aspect the closed loop further comprises a thermal fluid reservoir, such as an insulated fluid tank that serves as a reservoir of heated thermal fluid. In this aspect, heating control may be reliably provided even at times when the generator is not running.
Any number and kinds of heat exchangers may be used so as to provide desired heat exchange characteristics, which may depend on parameters such as thermal fluid type, flow rates, desired temperatures, outlet exhaust temperature, and the like. In an aspect, the heat exchanger is capable of increasing a thermal fluid temperature of thermal fluid introduced to the heat exchanger by a range selected from between 5° C. and 50° C.
Further temperature control in the system may comprise a cooling tower to remove heat from any portion of the system. For example, a cooling tower may be fluidically connected to the absorption chiller. In this manner, if the fluid in the absorption chiller is too hot, the cooling tower may decrease the temperature. If the fluid is at a desired temperature (or below), the cooling tower may be fluidically disconnected, such as by a flow-control valve.
The chilled thermal fluid loop of any of the systems provided herein may comprise a chilled loop inlet to the absorption chiller and a chilled loop outlet from the absorption chiller. In this aspect, the absorption chiller is capable of reducing a temperature of chilled water introduced to the absorption chiller by a range selected from between 5° C. and 20° C., such as a temperature decrease between liquid in the chilled loop inlet and the chilled loop outlet.
In an aspect, the recirculating thermal fluid loop thermally connected to the absorption chiller transports a steam and heated water composition within a conduit having a temperature that is greater than or equal to 200° F. Alternatively, the heated water composition may remain substantially in liquid form, but at a temperature that is less than boiling for the given pressure conditions within the conduit.
The chilled thermal fluid loop of any of the systems provided herein may further comprise a chilled thermal fluid supply line having a first end and a second end, wherein the chilled thermal fluid supply line first end is thermally connected to the absorption chiller and the chilled thermal fluid supply line second end is thermally connected to the enclosed space for supplying cooling to the enclosed space; and a chilled thermal fluid return line fluidically connected to the enclosed space at a first end and to the absorption chiller at a second end, wherein the chilled thermal fluid return line returns chilled thermal fluid from the enclosed space to the thermal fluid reservoir. The connections to the absorption chiller may correspond to the chilled loop inlet and a chilled loop outlet.
The actual components, geometrical configuration, and physical parameters for the heating and cooling of enclosed spaces by the respective fluid loops are selected as desired to achieve desired temperatures in the enclosed space. For example, a forced air conduit positioned in the enclosed space and in thermal contact with the chilled (or heated) thermal fluid supply line to generate a cooled (or heated) air stream in the enclosed space to cool (or heat) the enclosed space. In one embodiment, the cooled air stream is forced to flow over the one or more optical light sources powered by the electrical power generator, thereby dissipating heat build-up in the lights. Airflow may be provided by one or more blowers or fans, including blowers or fans that are powered by the generator.
In an aspect, the invention is further described in terms of components used to ensure a reliable and controllable supply of CO2 to the enclosed space. In one embodiment, any of the systems further comprise a filter positioned in the CO2 conduit or positioned upstream of the CO2 conduit for generating a CO2 rich gas in the CO2 conduit that is introduced to the enclosed space. The filter may remove unwanted species from the outlet exhaust gas, such as chemicals that are not desirable for applications that are agricultural growth in enclosed spaces. In an aspect, at least 80%, at least 90%, or at least 95% of an unwanted species is removed. In an aspect, the CO2 provided to the enclosed space is at least 80% CO2, at least 90% CO2, or at least 95% CO2, with the remainder mainly air.
In an aspect, the systems provided herein further comprise a CO2 storage vessel fluidically connected to the CO2 conduit for storing CO2 from the exhaust gas. In this configuration, CO2 may be stored for later on-demand use. For example, CO2 may then be provided even when the generator is not running.
In another embodiment, any of the systems may further comprise a CO2 sensor in the enclosed space for measuring CO2 concentration and a flow valve positioned in the CO2 conduit, wherein the flow valve is operably connected to the CO2 sensor to control a flow-rate of CO2 rich gas in the CO2 conduit to achieve a desired CO2 concentration.
Similar temperature sensors may be employed for the control of temperature in the enclosed space, such as be affecting flow rates or temperatures in the heated and/or chilled thermal fluids provided to the enclosed space. For example, precise and relatively rapid temperature control may be provided by cross-conduits between the heated and chilled thermal fluids along with pump and flow control valves, wherein mixture of high and low temperature thermal fluids provides the ability to control temperature over a range between the high and low temperatures.
In an aspect, the system provides CO2 concentration in the enclosed space selected from a range that is greater than or equal to 1000 ppm and less than or equal to 1500 ppm.
Another advantage of the systems herein where the outlet gas from the generator is used for heating, cooling and CO2 control of an enclosed space, is that the process may be considered a “green” process in that CO2 generated by hydrocarbon combustion may be captured in the form of plant growth. Furthermore, if there is excess CO2, it may be stored in a CO2 containing vessel for use in other applications. If the excess CO2 is not needed, post-combustion carbon capture equipment fluidically connected to the downstream exhaust outlet may be used. Examples of such equipment include one or more of chemical absorbers, chemical adsorbers, scrubbers, storage vessels, and underground geological formations for natural storage.
In an embodiment, the systems described herein relate to at least 50% of the CO2 generated by the hydrocarbon-fueled generator is used for plant growth and/or is captured by the post-combustion carbon capture equipment. In an aspect, even higher levels of CO2 are captured, such as at least 60%, at least 80%, at least 95%, or at least 99%.
Even further efficiency may be achieved by use of a biogas upgrader fluidically connected to the CO2 conduit; and a natural gas output line having a first end and a second end, wherein the first end is connected to the biogas upgrader and the second end is operably connected to the electrical power generator, where natural gas produced by the biogas upgrader is a fuel source of the electrical power generator. Removed CO2 may then be reintroduced to the system for use by growing plants in the enclosed space.
In an aspect, the system further comprises an anaerobic digester connected to the biogas upgrader, wherein the anaerobic digester breaks down agricultural waste matter generated from plant growth in the enclosed space to produce a biogas stream that is provided to the biogas upgrader, wherein the biogas upgrader separates CO2 gas and unwanted species to generate substantially pure natural gas provided to the natural gas output line. This further reduces operation costs by the process that itself provides a hydrocarbon fuel used by the generator.
The systems provided herein are compatible with any number of thermal fluids. Examples include each of the recirculating thermal fluid loop, heated thermal fluid loop, and chilled thermal fluid loop having a thermal fluid that is independently selected from: water, a water/glycol mixture or glycol. In an aspect, any of two or three thermal fluids in the two or three loops are identical.
Also provided herein are methods for climate control of an enclosed space by any of the systems provided herein.
In an embodiment, provided is a method for controlling a climate in an indoor agricultural producing space. Electrical power is generated by combustion of a hydrocarbon fuel, wherein the generating also provides a high temperature exhaust gas stream. Electrical power is provided to a power consuming device. For example, the power consuming device may be in the indoor agricultural producing space, such as a light source, a sensor (temperature, humidity), a blower or fan, or may be associated with the method, such as a pump, conventional air chiller, heater, flow-control valves, sensors of a physical parameter (e.g., temperature, flow-rate, pressure, concentration). The high temperature exhaust gas stream is introduced to a heat exchanger to heat a heat exchange liquid. Thermal heating control of the indoor agriculture producing space is provided with the heated heat exchange liquid. An absorption liquid chiller is powered with the heated heat exchange liquid to chill an absorption liquid. Thermal cooling control of the indoor agriculture producing space is provided with the chilled absorption liquid. High temperature exhaust gas stream is removed from the heat exchanger, such as a high temperature exhaust gas stream that was introduced to the heat exchanger at an inlet port and used to heat a thermal fluid in the heat exchanger, and then removed at a somewhat lower temperature from the heat exchanger at an outlet port. Carbon dioxide (CO2) is obtained from the removed high temperature exhaust gas stream and provided to the indoor agriculture producing space, to control CO2 levels in the space. In this manner, the two thermal loops, one having chilled thermal fluid and the other having heated thermal fluid provides temperature control of the enclosed space. CO2 obtained from the exhaust gas of the generator provides CO2 control. The generator provides electricity for the process. In this manner, the methods provided herein may be referred as a “quad-generation” for indoor agricultural production, where the method provides: (1) electricity; (2) heating; (3) cooling; and (4) CO2 in a reliable, cost effective, and efficient manner to an enclosed space, such as an indoor agriculture producing space.
In an aspect, the heat exchange liquid (or thermal fluid) comprises water or a water/glycol mixture. The processes and systems provided herein, however, are compatible with any number of heat exchange liquid or thermal fluids, so long as the fluid does not freeze under foreseeably operating conditions. Water and water/glycol mixtures are preferable as they are relatively inexpensive, are relatively not toxic, and are easily handled. In an aspect, the absorption liquid comprises water or a water/glycol mixture. In an aspect, the absorption liquid and the heat exchange liquid are different liquids. In an aspect, the absorption liquid and the heat exchange liquid are the same liquids.
In an embodiment, the hydrocarbon fuel comprises natural gas and the electrical power is generated by a natural gas turbine or a microturbine. In this manner, cost certainty may be secured over a long period of time via the purchase of natural gas on a contract over a long period of time.
In an aspect, the power consuming device comprises one or more optical light sources that provide light to one or more plants grown in the agricultural producing space. The chilled loop may be used to generate a cooled air stream that is forced over the lights or is in thermal contact with the light sources for heat convection from the optical light sources. In this manner, cooling can be provided to localized regions in the enclosed space. Similarly, heating may be provided to localized regions in the enclosed space, such as to a region corresponding to growing plants. In an aspect, such as during times when plant lights are off and plants are not undergoing photosynthesis, CO2 to the enclosed space may be turned off, along with cooling, and heating provided to the enclosed space to ensure plants are maintained at an adequate temperature. This heating is facilitated by the heated thermal fluid reservoir in thermal connection with the heating loop that ensures the heating loop is maintained at a sufficiently high temperature even when the generator is not running. Accordingly, appropriate flow control valves may be engaged so that the only flowing fluid is in the heated thermal fluid loop.
In an embodiment, the optical light sources are cooled by the chilled absorption liquid. The cooling may be by direct cooling where liquid conduits are in direct thermal contact with a part of the optical light source, such as a reflector, so that a heat sink is effectively provided to components that otherwise generate unwanted heat. Alternatively, the cooling may be indirect, with one or more additional components there between, such as forced air over the chilled conduit, with the chilled air subsequently provided to the to-be-cooled component. One example of a light source that may be cooled is a light source that is part of the “Modular Stepped Reflector”, of U.S. Provisional App. No. 61/987,905 filed May 2, 2014, which is specifically incorporated by reference herein, particularly, for airflow connections such as duct flanges for connection to air ducts containing chilled air.
In an aspect, the chilled absorption liquid indirectly cools the optical light sources by cooling an air stream in thermal contact with the chilled absorption liquid and the optical light sources.
Any of the methods or systems provided herein may relate to an indoor agricultural producing space that is a substantially closed loop agricultural system. In this aspect, “substantially closed loop” refers to the ability to precisely track and control resources put into the system and resources removed from the system. For example, aspects of the systems and methods provided herein relate to the ability to provide good growth conditions solely by combustion of hydrocarbon fuel in the generator. Soil, fertilizer and other source materials put into the system are similarly easily tracked. Removed materials include agricultural product from the plants, waste plant matter (e.g., the non-commercially useful portion of the plant), and waste soil. In this manner, raw material input is readily and precisely tracked, along with corresponding commercially valuable output and less valuable waste matter from the process.
In an aspect, substantially complete climate control is provided by the method without external energy input. In this aspect, “substantially complete climate control” refers to the system that does not generally require input of energy from an external source in the form of the electrical grid. As desired, of course, the system may rely on other passive external inputs, such as sunlight for greenhouse application, passive heating or cooling from the surrounding environment, and/or other forms of alternative energy that is not dependent on the grid, such as solar, wind, or geothermal. One advantage, however, of the systems provided herein, is the ability to control climate in the enclosed space based solely on the combustion of the hydrocarbon containing fuel along with electrical and heated exhaust gas generation by the electrical generator.
In an aspect, any of the methods and systems provided herein are referred to as being of “high-efficiency” and/or “ecologically friendly.” In an embodiment, at least 60% of the energy of the combustion step is used in the systems or methods provided herein. In contrast, electricity generators are about 30% efficient, with the majority of energy being wasted in the form of heat that is dissipated as waste heat to the surrounding environment. The instant methods and systems, in contrast, harness the heat that is otherwise wasted to actively control heating, thereby increasing overall efficiency.
In an aspect, the enclosed space such as an indoor agricultural producing space has a volume that is selected from a range that is greater than or equal to 1 m3 and less than or equal to 10,000 m3. Also provided herein are methods and systems having a plurality of hydrocarbon-fueled electrical power generators. The outlet exhaust generated by the plurality of generators may be combined in a single exhaust outlet conduit, such as to provide temperature and CO2 control for the large size enclosed spaces. Alternatively, the generators may be configured to provide a plurality of distinct and separate climate controls.
In an embodiment, the method and systems relate to at least 30 MW of electricity generation by a generator. Of course, the methods and systems provided herein are generally compatible with any size generator, including microturbines, so that the electrical generation may be on the order of about 30 kW or greater. In general, the larger the enclosed space, the larger the generator or plurality of generators used.
In an aspect, the heated heat exchange liquid is heated to a temperature that is greater than 80° F., greater than 90° F., or greater than 100° F. for the step of providing thermal heating control of the indoor agricultural producing space.
In an aspect, the heated heat exchange liquid is heated to a temperature that is greater than 100° F., greater than 150° F. or greater than 200° F., including heated to provide a combined steam/hot water input for the step of powering the absorption liquid chiller.
In an embodiment, the method further comprises the steps of removing the heated heat exchange liquid from the absorption chiller and storing the removed heated heat exchange liquid in a thermal fluid reservoir. This can be useful for providing a large and stable source of heated heat exchange liquid for subsequent use in, or use by, the heated exchange liquid (e.g., heated thermal fluid) in a heated thermal fluid loop that provides heating control of the enclosed space. Accordingly, this heating can then occur even under conditions where the generator is not running.
In an aspect, the step of providing thermal heating control comprises removing heated heat exchange liquid from the thermal fluid reservoir, transporting the removed heated heat exchange liquid to the agricultural producing space, and returning the transported heated heat exchange liquid to the thermal fluid reservoir.
In an embodiment, the chilled absorption liquid is chilled to a temperature that is greater than or equal to 44° F. and less than or equal to 70° F. for the step providing thermal cooling control of the agricultural producing space.
In an aspect, the step of providing thermal cooling further comprises transporting chilled absorption liquid from the absorption liquid chiller to the agricultural producing space, cooling at least a portion of the agricultural producing space, or a heat generating electrical component associated therewith, with the transported chilled absorption liquid, wherein after cooling, the absorption liquid is at an elevated temperature; and returning the elevated temperature absorption liquid to the absorption chiller for chilling.
In an embodiment, the cooling step further comprises cooling air in thermal contact with the chilled absorption liquid, and forcing the cooled air over the heat generating electrical component. In an aspect, the heat generating electrical component comprises one or more optical light sources used for agricultural production. In an aspect, the cooled air has a temperature that is less than or equal to 70° F.
The systems and methods provided herein are compatible with a wide range of fluid flow rates, dependent in part on the heat transfer conditions as well as operating conditions. In an aspect, the transported chilled absorption liquid has a flow-rate that is greater than or equal to 1 gallon per minute and less than or equal to 10 gallon per minute. Similar flow-rates may be provided for the heated heat exchange liquid in the loop that provides heating control of the enclosed space.
In an aspect, any of the liquids are forced to flow by one or more pumps. In an aspect, the hot exhaust flow is provided by the generator which during operation forcefully expels exhaust gas from the engine. In the event the exhaust flow of hot gas is insufficient, the exhaust may be stored in a storage tank and brought up to a desired pressure to provide desired flow characteristics downstream. Alternatively, a pump may be used to force hot exhaust along with accompanying heated air to a desired flow rate or pressure.
Any of the methods or systems provided herein further comprise a post-combustion carbon capture technique, such as for capturing and/or storing CO2 for subsequent use for plant growth or to avoid unwanted emission to the surrounding environment. In an aspect, the post-combustion carbon capture technique is a technique selected from the group consisting of: filtering; absorption; adsorption; chemical reaction; or a combination thereof.
To further improve efficiency and avoid waste, any of the methods herein further comprise the steps anaerobically digesting waste plant matter from plants grown in the indoor agriculture producing space to generate a biogas. CO2 and unwanted contaminants are removed from the biogas to generate commercial-grade natural gas. The generated commercial-grade natural gas is provided as a fuel source for the generating electrical power step.
In an aspect, substantially all CO2 is used in the method or stored, thereby substantially avoiding release of CO2 to the surrounding environment. For example, less than 50%, less than 30%, less than 10% or less than 5% of the CO2 generated by the combustion of hydrocarbon containing fluid is released to the surrounding environment in the form of CO2 gas. In this manner, the methods and systems provided herein may be characterized as “environmentally friendly.”
In another embodiment, the invention is a device for implementing any of the methods provided herein.
Without wishing to be bound by any particular theory, there may be discussion herein of beliefs or understandings of underlying principles relating to the devices and methods disclosed herein. It is recognized that regardless of the ultimate correctness of any mechanistic explanation or hypothesis, an embodiment of the invention can nonetheless be operative and useful.
In general, the terms and phrases used herein have their art-recognized meaning, which can be found by reference to standard texts, journal references and contexts known to those skilled in the art. The following definitions are provided to clarify their specific use in the context of the invention.
“Enclosed space” refers to any building, or portion thereof such as rooms, where climate control is desired. As used herein, “climate control” or “controlling climate” refers to the ability to simultaneously provide heating, cooling, CO2 concentration and electricity. Of course, the ability to provide simultaneous heating and cooling may be combined so as to provide temperature control in a single system, regardless of whether cooling or heating is required to achieve the desired temperature. The term is used broadly herein and includes enclosed spaces that are not airtight. This is a reflection that the invention can accommodate defined spaces having open windows or other ventilation openings or periodic opening of doors with the surrounding environment.
“Electrically powered component” is used broadly herein to refer to any device run on electrical power useful in the application of interest. For example, for enclosed space used to grow plants, sensors that monitor physical parameters that impact plant growth are relevant including temperature, CO2, humidity, soil conditions, light levels, may be electrically powered, with independent battery back-up. Other relevant components include those required to ensure the process and systems provided herein perform as desired and may include pumps, flow controllers, flow control valves, in-line temperature and/or pressure sensors, heaters, coolers, and the like. Another relevant electrically powered component particularly useful for indoor agriculture applications are lights that provide desired wavelengths to facilitate plant growth and photosynthesis.
“Operably connected” refers to a configuration of elements, wherein an action or reaction of one element affects another element, but in a manner that preserves each element's functionality. For example, the action of an electrical power generator that produces electricity and exhaust gas may be operably connected to an exhaust outlet conduit without affecting the ability of the generator to generate electricity or affect the ability of the conduit to confine and transport the exhaust gas. In this example, the generator is said to be operably connected to the exhaust outlet.
“Thermally connected” refers to a configuration of elements, wherein the temperature of one element is able to influence or control the temperature of another element. For example, fluids are considered thermally connected when a first fluid is able to reliably affect a temperature change in a second fluid. The elements may or may not be in physical contact. For example, a first fluid may be in a pipe connected to fins or radiator elements for maximizing heat transfer with surrounding air. Such a configuration is referred herein as a “closed-loop” system. Alternatively, a first fluid may be introduced to a thermal reservoir of the first fluid that is maintained at a desired temperature, and then the first fluid removed from the thermal reservoir. Such a configuration is referred herein as an “open-loop” system because the fluid is not self-contained in the loop but instead may have openings.
“Fluidically connected” refers to a configuration of elements, wherein the fluid can flow from or between one element and another without adversely affecting the functionality of the elements and without substantial leakage.
“Thermal fluid” or “heat exchange liquid” is generally used interchangeably and refers to a fluid that is selected for its heat transfer characteristics. The fluid is preferably a liquid that is readily transported within conduits between components or in a loop configuration. Any of the thermal fluids provided herein may be transported by use of one or more pumps or may be transported under a natural pressure head without need for active pumps. A thermal fluid is useful for transferring thermal energy from one physical component or location to another. For example, a thermal fluid that has been heated to a relatively high temperature may be used for heating. Similarly, a thermal fluid that has been chilled to a relatively low temperature may be used for cooling. Thermal transfer components known in the art may be incorporated as desired, including one or more of radiators, heat exchangers, blowers, fans, or the like that are in direct or indirect thermal contact with the thermal fluid. An example of indirect thermal contact is a blower that blows air over or through a radiator that contains a source of thermal fluid at a desired temperature.
Examples of thermal fluids that may be used in systems and process provided herein include water, glycol, ethylene glycol, propylene glycol, and combinations thereof, such as water/glycol mixtures.
“High temperature”, in the context of high temperature exhaust gas, refers to a temperature that is sufficiently high so as to be useful in heating a thermal fluid to a temperature that can operably power an absorption chiller. The exact temperature depends on the operating conditions of the generator. Typical hydrocarbon-fueled generators, however, may have exhaust temperatures of about 300° C. to about 700° C., depending on the generator characteristics, fuel source, and operating conditions.
A “fluid loop” refers to a fluid flow circuit provided to a component in a supply line and correspondingly returned from the component by a return line, without substantial loss of fluid. Although the fluid may be a gas or a liquid, in various embodiments the fluid is a liquid having good thermal properties and that is able to be pumped at desired flow rates so as to maximize heat exchange, thermal control, and the like. In an aspect for high temperatures, the fluid may comprise a mixture of water in liquid and steam forms.
“Anaerobic digester” refers to a device that provides a collection of processes by which microorganisms break down a feedstock such as plant matter in the absence of oxygen, to produce a natural gas. Typically, the gas in the anaerobic digester is about 55% to 65% methane, and about 35% to 45% CO2, and trace amount of other gases, such as about 1% to 2% H2S and hydrogen. A “biogas upgrader” is used to further refine the biogas such as by chemical treatment or scrubbing to achieve natural gas that may be used as a fuel for the generator. To remove H2S an amine gas treatment may be used, as known in the art. Alternatively, chemicals such as FeCl2 may be used to inhibit H2S production. In an aspect, the biogas upgrader removes a substantial portion of carbon dioxide, hydrogen sulphide, water and contaminates from the biogas to achieve substantially pure methane or biomethane which is interchangeable with natural gas. Examples of processes used in the biogas upgrader to achieve substantially pure methane includes one or more of water washing, pressure swing adsorption, dissolving of acid gases and/or amine gas treatment. Substantially pure methane refers to about 95% or greater, 98% or greater, or 99% or greater methane.
The high temperature exhaust gas may also be used for obtaining CO2 in step 470 and to provide a controllable level of CO2 480 in the enclosed space 5. The high temperature exhaust gas provided for subsequent CO2 capture/storage may actually be exhaust gas that has already been used to heat a thermal fluid and so may be of lower temperature, such as exhaust gas that exits a heat exchanger. As desired, the exhaust to the environment is then low temperature, CO2 poor gas 485.
Optionally, waste plant matter from the indoor agriculture production facility may be used to generate biogas 490. The biogas 490 may be refined into separate CO2 492 provided to the enclosed space 5 and substantially pure natural gas 495 that may be used at least as a fuel supplement 497 in the combustion step 400.
Enclosed space 5 is illustrated as having a number of inputs for indoor agricultural production, including soil 6 and nutrient input 7 (e.g., fertilizers and the like), as well as an agricultural harvest output 8. Other relevant inputs are the subject of the instant invention and include electrical 20, heating 76, cooling 88 and CO2 112, as explained herein below.
A hydrocarbon-fueled electrical power generator 10 provides electrical power such as by electrical power line 20. The electrical power line 20 is illustrated as connected to enclosed space 5 and may be used, for example, to power grow lights in the enclosed space. Line 20, of course, may also power any other electrical power device used in the system, such as pumps used to achieve desired flow rates in any of the flow conduits, sensors, controllers, valves or any other electrically powered component of the system.
Generator 10 also generates a flow of hot exhaust gas which is transported to a heat exchanger 40 by exhaust outlet conduit 30. The heat exchanger facilitates heat exchange between the heated exhaust gas and a relatively cooler thermal liquid provided to the heat exchanger. Various types of heat exchangers may be used in the system. Examples of different flow arrangements include parallel flow, counter-flow, and cross-flow heat exchangers. Examples of different types include, but are not limited to, double pipe, shell and tube, plate, plate and shell. A recirculating thermal fluid loop 50 is connected to the heat exchanger to provide a thermal fluid 51 to the heat exchanger for heating and to remove a heated thermal fluid 42 from the heat exchanger. An absorption chiller 60 is thermally connected to the recirculating thermal fluid loop 50, such as at a heated thermal fluid conduit containing the heated thermal fluid 42 that runs between the heat exchanger and the absorption chiller 60.
Heated thermal fluid 42 exits the absorption chiller 60 at a thermal fluid outlet conduit 44 from the absorption chiller. A heated thermal fluid loop 70 is in thermal contact with the recirculating thermal fluid loop 50. In this example, the thermal contact is illustrated as part of a heated thermal fluid reservoir 700. Alternatively, the heated thermal fluid loop 70 may be an integral part of the recirculating thermal fluid loop 50 to form a single larger loop. A first end of the heated thermal fluid loop is illustrated by 72 and 74 in thermal contact with recirculating thermal fluid loop 50, and specifically at the heated thermal fluid reservoir 700. A second end of the heated thermal fluid loop is illustrated by 76 and 78 in thermal contact with enclosed space 5. Accordingly, heated thermal fluid loop 70 provides heating control of enclosed space 5. Heated thermal fluid loop is further illustrated as having heated thermal fluid supply line 730 and heated thermal fluid return line 740. Ends of lines 730 and 740 correspond to elements 74 and 76 and 72 and 78. Open loop configuration then may refer to thermal fluid that is provided to reservoir 700 at 72 and provided from reservoir 700 to heated thermal fluid loop at 74. In contrast, a closed loop configuration refers to heated thermal fluid in the loop 70 that is maintained physically separate from the thermal fluid in reservoir 700. A coil or other heat exchange element may then be disposed in the reservoir 700 to provide heating of thermal fluid that has traversed the loop 70 and may require heating from the reservoir 700 to achieve a desired heating temperature of the enclosed space.
Chilled thermal fluid loop 80 comprises a first end (8284) in thermal contact with the absorption chiller and a second end (8688) in thermal contact with enclosed space 5. Accordingly, chilled thermal fluid loop 80 provides cooling control of enclosed space. Chilled thermal fluid loop is further illustrated as having chilled thermal fluid supply line 830 and chilled thermal fluid return line 840. Ends of lines 830 and 840 correspond to elements 82 and 88 and 84 and 86.
Forced air conduit (not shown) may be disposed in enclosed space 5 and in thermal contact with the chilled thermal fluid loop 80 for a source of chilled air to cool an optical light in the enclosed space.
Downstream exhaust outlet conduit 90 is connected to the heat exchanger 40 at a first end to remove exhaust gas from the heat exchanger. The removed exhaust gas is of lower temperature than the high temperature exhaust gas that was introduced to the heat exchanger by conduit 30 as a portion of the thermal energy is transferred to thermal fluid in the heat exchanger to raise the temperature of the thermal fluid. The exhaust gas in the conduit 90, therefrom, may be described as being of low temperature and CO2 rich. A CO2 conduit 110 has a first end 111 fluidically connected to the downstream exhaust outlet conduit 110 and a second end 112 fluidically connected to the enclosed space 5 to provide desired levels of CO2 to the enclosed space. As desired a CO2 sensor may be operably connected to a flow-control valve to provide CO2 as needed (see, e.g.,
A filter 102 positioned in the conduit 110 may facilitate production of a CO2 rich gas. CO2 storage vessel 100 may store excess CO2. Carbon capture equipment 95 fluidically connected to conduits 90 and 110 may facilitate capture of desired CO2.
The systems and methods provided herein are compatible with biogas generation to produce a source of hydrocarbon fuel from plants grown in the enclosed space 5. For example, waste plant matter 118 may be removed from the enclosed space and provided to an anaerobic digester 120 containing microbes in an anaerobic environment so as to breakdown the waste plant matter and generate a biogas. The biogas is provided to a biogas upgrader 130 containing equipment, components and processes to refine the biogas into a commercially pure natural gas and separate out CO2 gas and unwanted contaminants (e.g., H2S). That commercially pure natural gas is provided as a fuel source to the generator 10 by a natural gas output line 497 having one end connected to the biogas upgrader and a second end operably connected to the generator 10. For example, an output line 497 may be connected to a fuel tank that is in turn connected to the generator or used as a source of fuel for the generator.
Waste that cannot be used in biogas generation is removed, as indicated by 116. In this manner, very little unwanted waste remains, with use of most of the plant matter and efficient use of the hydrocarbon fuel with minimal uncontrolled release of pollutants or CO2 gases to the surrounding environment.
Heated thermal fluid reservoir 700 provides a number of benefits to the systems and processes provided herein. First, a large reservoir of heated thermal fluid provides a base reservoir of thermal energy to provide rapid on-demand heating, as needed. In this manner, even if the generator 10 is not running, there is a reliable source of high thermal energy to continue to provide heating control via heated thermal loop 70. Reservoir 700 has a heated thermal fluid inlet 710 that provides heated thermal fluid that has exited the absorption chiller, and a heated thermal fluid outlet 720 connected to the heat exchanger 40 by flow conduit 725 to provide heating of thermal fluid that has transited the loop 50. Reservoir inlet and outlet are provided to fluidically and/or thermally connect at heated thermal fluid first end or inlet 72 and outlet 74.
The invention is able to accommodate variations in the geometry. For example, the absorption chiller may instead be positioned downstream of the thermal fluid reservoir 700 and upstream of the heat exchanger 40, instead of downstream of the heat exchanger and upstream of the fluid reservoir, as illustrated in
Absorption chiller 60 is an energy efficient manner to obtain chilled thermal fluid in an indirect manner, wherein heated thermal fluid is used to drive chilling of a thermal fluid for subsequent cooling control. A cooling tower 62, connected to the absorption chiller via cooling tower inlet line 64 and cooling tower outlet line 66, provides additional temperature control in the absorption chiller.
All references throughout this application, for example patent documents including issued or granted patents or equivalents; patent application publications; and non-patent literature documents or other source material; are hereby incorporated by reference herein in their entireties, as though individually incorporated by reference, to the extent each reference is at least partially not inconsistent with the disclosure in this application (for example, a reference that is partially inconsistent is incorporated by reference except for the partially inconsistent portion of the reference).
The terms and expressions which have been employed herein are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by preferred embodiments, exemplary embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention as defined by the appended claims. The specific embodiments provided herein are examples of useful embodiments of the present invention and it will be apparent to one skilled in the art that the present invention may be carried out using a large number of variations of the devices, device components, methods steps set forth in the present description. As will be obvious to one of skill in the art, methods and devices useful for the present methods can include a large number of optional composition and processing elements and steps.
When a group of substituents is disclosed herein, it is understood that all individual members of that group and all subgroups, are disclosed separately. When a Markush group or other grouping is used herein, all individual members of the group and all combinations and subcombinations possible of the group are intended to be individually included in the disclosure.
Every formulation or combination of components described or exemplified herein can be used to practice the invention, unless otherwise stated.
Whenever a range is given in the specification, for example, a temperature range, a flow range, an efficiency range, a time range, or a composition or concentration range, all intermediate ranges and subranges, as well as all individual values included in the ranges given are intended to be included in the disclosure. It will be understood that any subranges or individual values in a range or subrange that are included in the description herein can be excluded from the claims herein.
All patents and publications mentioned in the specification are indicative of the levels of skill of those skilled in the art to which the invention pertains. References cited herein are incorporated by reference herein in their entirety to indicate the state of the art as of their publication or filing date and it is intended that this information can be employed herein, if needed, to exclude specific embodiments that are in the prior art. For example, when composition of matter are claimed, it should be understood that compounds known and available in the art prior to Applicant's invention, including compounds for which an enabling disclosure is provided in the references cited herein, are not intended to be included in the composition of matter claims herein.
As used herein, “comprising” is synonymous with “including,” “containing,” or “characterized by,” and is inclusive or open-ended and does not exclude additional, unrecited elements or method steps. As used herein, “consisting of” excludes any element, step, or ingredient not specified in the claim element. As used herein, “consisting essentially of” does not exclude materials or steps that do not materially affect the basic and novel characteristics of the claim. In each instance herein any of the terms “comprising”, “consisting essentially of” and “consisting of” may be replaced with either of the other two terms. The invention illustratively described herein suitably may be practiced in the absence of any element or elements, limitation or limitations which is not specifically disclosed herein.
One of ordinary skill in the art will appreciate that starting materials, biological materials, reagents, synthetic methods, purification methods, analytical methods, assay methods, and biological methods other than those specifically exemplified can be employed in the practice of the invention without resort to undue experimentation. All art-known functional equivalents, of any such materials and methods are intended to be included in this invention. The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention that in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by preferred embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention as defined by the appended claims.
This application claims the benefit of U.S. Provisional Patent Application No. 62/018,414 filed on Jun. 27, 2014, which is herein incorporated by reference in its entirety to the extent not inconsistent herewith.
| Number | Date | Country | |
|---|---|---|---|
| 62018414 | Jun 2014 | US |
