The present embodiment generally relates to solar energy collection, and in particular, it concerns optimizing the allocation of solar radiation between applications.
Modern facilities use solar energy for a variety of applications. Three primary uses of solar energy are for heating, electrical power, and lighting. Referring to
Existing solar energy collection systems typically address only a single aspect, or at most two of these three primary uses of solar energy. As a result, the available solar energy falling on the external surfaces of a structure is not optimally utilized to meet the energy or commercial needs of the occupants or associated entities. An example of a conventional solar collection system is European patent application EP1993145, to Massimo Sillano for Solar energy collection panel for rooftop and similar installation, which teaches a mechanical system for “the exposure of the solar (thermal) collector only under optimum conditions of solar radiation, otherwise providing the total or partial covering of the solar collector itself by the photovoltaic collector.” Similar hybrid solar thermal/photovoltaic products are commercially available to alter the use of a given amount of solar exposure based on the environment or facility usage.
There is therefore a need for a method and system for allocating solar radiation between multiple applications based on optimization of multiple parameters.
According to the teachings of the present embodiment there is provided a solar allocation and distribution system including: an allocation sub-system; a distribution sub-system; and a controller configured for controlling the allocation sub-system and the distribution sub-system based on optimizing a cost function, wherein the cost function is time-dependent and based on energy utilization of a facility.
In an optional embodiment, the solar allocation and distribution system includes an array of reflectors that are independently adjustable by the controller in orientation along a given axis of each of the reflectors. In another optional embodiment, the solar allocation and distribution system includes one or more secondary reflectors configured to distribute solar radiation to one or more solar applications. In another optional embodiment, the reflectors are dichroic reflectors. In another optional embodiment, the solar allocation and distribution system includes an array of dichroic reflectors configured to distribute respective spectrums of incoming solar radiation between solar applications. In another optional embodiment, the solar allocation and distribution system includes a uni-axial opto-mechanical architecture, wherein the uni-axial control is East-West.
In an optional embodiment, the allocation subsystem includes at least two components selected from a group consisting of: solar thermal collectors; solar photovoltaic collectors; optically adjustable skylights; and optical lightguides for internal illumination.
In another optional embodiment, the system further include an array of reflectors that are dynamically configured to provide solar radiation to at least two components selected from a group consisting of: solar thermal collectors; solar photovoltaic collectors; optically adjustable skylights; and optical lightguides for internal illumination.
In an optional embodiment, the controller is configured to control the solar allocation and distribution system to provide solar radiation to at least two applications selected from the group consisting of: thermal conversion; photovoltaic conversion and light transmission. In another optional embodiment, the controller is configured to dynamically control the solar allocation and distribution system to provide solar radiation based on the cost function being time-dependent on a time of day.
In an optional embodiment, the cost function is additionally based on at least two parameters selected from a group consisting of: commercial parameters derived from energy use of the facility; environmental parameters derived from an environment of the facility; environmental parameters derived from an environment of the solar allocation and distribution system; technical parameters derived from the solar allocation and distribution system; and economic parameters derived from energy usage costs.
In another optional embodiment, the controller is configured to dynamically control the solar allocation and distribution system to provide solar radiation based on optimizing the cost function to minimize the expense of providing energy to a facility.
According to the teachings of the present embodiment there is provided a method including the steps of: providing a solar allocation and distribution system for supplying solar radiation to a plurality of applications; and distributing the solar radiation among the plurality of applications according to a cost function that is time dependent and based on energy utilization of a facility.
In an optional embodiment, the step of distributing includes dynamically controlling the allocation of solar radiation based on the cost function being time-dependent on a time of day.
In an optional embodiment, the cost function is additionally based on parameters derived from at least two parameters selected from a group consisting of: commercial parameters derived from energy use of the facility; environmental parameters derived from an environment of the facility; environmental parameters derived from, an environment of the solar allocation and distribution system; technical parameters derived from the solar allocation and distribution system; and economic parameters derived from energy usage costs.
In an optional embodiment, the step of distributing includes controlling the allocation of solar radiation to at least two applications selected from the group consisting of: thermal conversion; photovoltaic conversion; light transmission; and electricity storage. In another optional embodiment, the step of distributing includes optimizing the cost function to minimize the expense of providing energy to the facility.
The embodiment is herein described, by way of example only, with reference to the accompanying drawings, wherein:
The principles and operation of the method and system according to a present embodiment may be better understood with reference to the drawings and the accompanying description. A present embodiment is a method and system for allocating solar radiation between multiple applications based on optimization of multiple parameters. The system facilitates dynamically allocating a variable amount of solar radiation to or between multiple solar applications based on optimizing a time-dependent cost function using multiple parameters as inputs to the cost function. Also described is an optical architecture that enables dynamically channeling incident solar radiation to or between multiple solar applications based on the optimization of a cost function.
In contrast to conventional hybrid solar thermal/photovoltaic products, that alter the use of a given amount of solar exposure based on the environment or facility usage, the current embodiment can allocate a variable amount of solar radiation based on optimization of a multiple-parameter cost function, including economic parameters. Since the cost function is dependent on parameters that can be variable in time, the channeling optical architecture itself must be adjustable in response to the changing cost function.
Referring now to the drawings,
A cost function is typically based on a plurality of inputs. The cost function can be based on multiple parameters, including, but not limited to commercial parameters 212, technical parameters 214, environmental parameters 216, and/or economic parameters. Optimization 210 of the cost function facilitates control of the solar allocation and, distribution system 200. References to a cost function should be understood to also include evaluation of the cost function in the context of business models, operational policies, and operational goals. Cost functions and optimization of cost functions are known in the art. Based on this description, one skilled in the art will be able to design and implement optimization of a cost function appropriate for a specific implementation.
A cost function is provided that is time-dependent and based on energy utilization of a facility. In the context of this document, the term energy utilization generally refers to the types and quantities of one or more forms of energy being used by a facility. Energy utilization includes, but is not limited to, how much water heating 106, hot water storage 220, space heating 108, space cooling 222, photovoltaic conversion 110 (such as electricity generation for running electrical appliances), electricity storage 116, and light transmission (lighting/light for illumination) 112 are needed in a facility 120 and time dependence of the utilization.
A cost function can be based on commercial parameters. Commercial parameters 212 or structural parameters are associated with a facility 120. Commercial parameters that can be taken into account in the optimization and distribution of available solar energy include, but are not limited to:
The above-listed examples of commercial parameters can be time-dependent. Time dependencies of commercial parameters include, but are not limited to varying energy utilization of a facility. Time dependency is typically most significant depending on the time (hour) of the day. Controlling the solar allocation and distribution system 200 includes controlling the allocation and distribution of solar radiation to one or more of a plurality of applications based on a time-dependent cost function, dependent on a time of day. Other time dependencies include, but are not limited to, day of the week, week of the year, monthly cycles, time of year, yearly use, and/or a periodic use. Non-limiting examples of commercial parameters that are dependent on the hour of the day include, but are not limited to: the minimum amount of area lighting that is needed for a facility during the night, an increased energy requirement at a given hour of the day as workers arrive at a facility, and a sufficient amount of area lighting for workers or customers during business hours. A non-limiting example of an a periodic use is a special event that will occur at a company's facility next week (in the future), for which an anticipated additional amount of energy will needed to be used on the day of the special event.
Commercial parameters can be derived from energy use of a facility. Depending on the implementation, economic factors can be included in the commercial parameters, or the cost function can be additionally based on a separate set of economic parameters. Economic parameters include, but are not limited to, the above-listed costs of electricity provided by a utility company, and price paid for electricity provided to a utility company (commonly known as “selling back” electricity to the grid). A preferred implementation is controlling the solar allocation and distribution system 200 based on optimizing the cost function to minimize the expense of providing energy to the facility. Economic parameters, including economic metrics can be used in the optimization of a cost function facilitating the selection and determination time dependent redistribution of the available solar energy between and among applications.
A cost function can be based on environmental parameters 216. Environmental parameters can be derived from an environment of the facility and/or environment of the solar allocation and distribution system. In the context of this document, the term environment generally refers to external conditions and/or surroundings. Environmental parameters that can be taken into account in the optimization and distribution of available solar energy include, but are not limited to:
The above-listed examples of environmental parameters can be time-dependent. A non-limiting example of environmental parameters that are dependent on time is the typical intensity of solar radiation on a particular day at a particular hour, which can be used to pre-configure the allocation sub-system 202 to take advantage of the anticipated solar radiation. Another example is the current temperature outside a building, or the direction and speed of change of temperature outside a building, which can be used to provide an appropriate amount of heating or cooling to the building, or collection of solar energy in anticipation of future needs. In other words, the temperature outside is getting colder, so generate more hot water now and store the hot water in hot water storage 220 while the sun is out, so we can use the hot water later in the day to heat the building.
A cost function can be based on technical parameters 214. Technical parameters are derived from the solar allocation and distribution system 200. Technical parameters that can be taken into account in the optimization and distribution of available solar energy include, but are not limited to:
The above-listed examples of technical parameters can be time-dependent. A non-limiting example of technical parameters that are dependent on time is the degradation in efficiency of photovoltaic cells over the lifetime of the photovoltaic cells. Depending on the implementation, economic factors can be included in the technical parameters. Economic parameters that are related to the technical parameters and/or solar collection and distribution include the costs of operating and maintaining the collection systems and associated applications.
Optimization 210 of the cost function for control of the solar allocation and distribution system 200 includes modifying the distribution of available solar radiation between applications to match an economic optimization function. To further clarify possible implementations of the current embodiment and advantages over conventional solar collection systems, the following non-limiting examples of optimization are now provided:
In a preferred implementation, the applications 102 include electricity storage 116, typically implemented as a battery system receiving generated electricity from photovoltaic conversion 110. Electrical storage 116 facilitates storage of excess electricity from photovoltaic conversion 110, or in other words, when energy usage of a facility is being met by the solar allocation and distribution system, additional solar radiation available to the allocation sub-system 202 can be distributed 204 for photovoltaic conversion 110 and electricity storage 116. Stored electricity can be saved for future usage or anticipated energy usage, or optionally sold back to a utility company 226.
Similar to electricity storage 116, the applications 102 can include hot water storage 220. Hot water storage 220 facilitates storage of excess hot water from water heating 106. In a case where the hot water usage of a facility is being met by the solar allocation and distribution system, additional solar radiation available to the allocation sub-system 202 can be distributed 204 for water heating conversion 106 and hot water storage 220. Stored hot water can be saved for future usage or anticipated energy usage.
Specific distribution and operation can be based on optimization of the cost function, in particular the economic parameters. An example optimization outcome is shown in
Referring now to
One aspect of the solar allocation and distribution system is an opto-mechanical architecture, as the architecture of the system includes both optical and mechanical components. The exemplary implementation of
The controller 320 can be implemented as a processing system including one or more processors. Processing can be centralized, or distributed throughout the system, as appropriate for a specific implementation. For clarity, connections between the controller 320 and other system components are not shown. Optionally, the controller 320 can be connected to environmental sensors. Environmental sensors include, but are not limited to, thermometers to measure temperature in the environment of the solar allocation and distribution system, the temperature in multiple areas outside the facility 120 (such as on several sides of a building), the temperature in multiple areas inside the facility 120, light detectors (such as photodiodes) to measure available solar radiation in the visible and IR spectrums during daylight hours (varies with time of day and degree of cloud cover), and electrical load sensors to measure the amount of electricity usage of a facility, optionally in one or more areas of the facility.
The controller can be optionally and/or additionally be in communication with:
The controller 320 can be configured with an associated cost function for allocating and distributing solar thermal energy that is required by more than one application. A non-limiting example is a distribution of fluid flowing from a solar thermal collector between either a solar cooling application or a domestic hot water application. A solar cooling application requires substantially higher temperature fluid than a domestic hot water application. The controller can monitor the temperature of fluid coming from the solar thermal collector and divert the fluid from domestic hot water to solar cooling as soon as the temperature of the fluid reaches a temperature required for solar cooling. When the temperature of the fluids drops below the temperature required for solar cooling (for instance later in the day when solar radiation levels diminish) the controller can divert the fluid back to domestic hot water later. A similar example can be envisaged in certain climates where solar cooling is required in the daytime and solar heating in the nighttime. In this case, the fluid flow can be switched from cooling to heating in the afternoon hours.
The implementation of an array of reflectors 302 can depend on the specifics of the operation of the system, and includes, but is not limited to the quantity of reflectors, type of reflector, array topology, and axis control. For a typical Northern hemisphere installation, in
In a uni-axial implementation, each reflector can be rotated on a single axis. A uni-axial implementation facilitates a simplified design and reduced costs, as compared to multi-axial designs. In a preferred implementation, each reflector is independently adjustable in orientation along an East-West axis. The current embodiment can be used with multi-axial designs, and based on this description one skilled in the art will be able to implement an appropriate reflector array. Reflectors can be planar or concave reflectors.
In one implementation, each of the reflectors in the array of reflectors 302 can be independently rotated, such that incoming light 300 is allowed to pass one or more of the reflectors and allowed to impinge 304 on solar thermal panel 306, or rotated such that incoming light 300 is reflected to secondary reflectors 310 and/or 316 for respective PV allocation 308 and/or illumination allocation 314 respectively to solar PV panel 312, and/or optically adjustable skylight(s) 318 or waveguides.
Reflectors can also be dichroic in design, allowing distribution between applications in the solar spectral dimension, in addition to distribution in the time domain. In an example implementation with dichroic reflectors, radiation outside the spectral domain of efficient photovoltaic conversion impinges entirely on the solar thermal collectors (arrows for thermal allocated 304 to solar thermal panel 306), while all photons of energy above the band gap of silicon are reflected towards the photovoltaic conversion panels (arrows for PV allocation 308 to solar PV panel 312).
In one implementation, the array of reflectors 302 is dynamically configured to provide solar radiation to at least two applications including thermal conversion, photovoltaic conversion, light transmission, and electricity storage or sellback to the grid. In a preferred implementation, the controller 320 optimizes a cost function that is time-dependent on a time of day. The controller can be configured to dynamically control the solar allocation and distribution system to provide solar radiation based on the cost function being time-dependent on a time of day. The cost function can be based on at least two parameters including: commercial, environmental parameters, technical parameters, and economic parameters. The controller can be configured to optimize a cost function that is based on a plurality of inputs, and evaluate the cost function in the context of business models, operational policies, and operational goals, which are used by the controller to control the solar allocation and collection system. Configuration of the controller includes being able to dynamically control the solar allocation and distribution system to provide solar radiation based on optimizing the cost function to minimize the expense of providing energy to a facility.
Additional and alternative options that can be included in the solar allocation and distribution system include, but are not limited to:
Integration of additional modules for optimization is foreseen. For example, a technique taught in U.S. Pat. No. 6,785,592 to Smith et al for System and method for energy management, teaches a business methodology for optimizing energy procurement, energy demand (usage), and energy supply for a facility or complex. The method of Smith et al could be added to an embodiment of the currently described system for solar allocation and distribution, for example on the “other side” of the facility, in other words, where electricity is purchased to provide the balance of energy not supplied by the solar allocation and distribution system. This method of Smith et al could provide additional inputs to the optimization function, for example the cost of electricity, for assisting in determining the optimal combination of collection and distribution.
Note that a variety of implementations for components and processing are possible, depending on the application. Processing is preferably implemented in software, but can also be implemented in hardware and firmware, on a single processor or distributed processors, at one or more locations. The above-described component functions can be combined and implemented as fewer modules or separated into sub-components and implemented as a larger number of modules. Based on the above description, one skilled in the art will be able to design an implementation for a specific application.
It will be appreciated that the above descriptions are intended only to serve as examples, and that many other embodiments are possible within the scope of the present invent on as defined in the appended claims.
This application claims the benefit of provisional patent application (PPA) Ser. No. 61/295,793 filed Jan. 18, 2010 by the present inventors, which is incorporated by reference.
Number | Date | Country | |
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61295793 | Jan 2010 | US |