WO2015063731A1 - A solar water heater controller - Google Patents

A solar water heater controller Download PDF

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Publication number
WO2015063731A1
WO2015063731A1 PCT/IB2014/065741 IB2014065741W WO2015063731A1 WO 2015063731 A1 WO2015063731 A1 WO 2015063731A1 IB 2014065741 W IB2014065741 W IB 2014065741W WO 2015063731 A1 WO2015063731 A1 WO 2015063731A1
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WO
WIPO (PCT)
Prior art keywords
controller
solar
solar radiation
water
solar water
Prior art date
Application number
PCT/IB2014/065741
Other languages
French (fr)
Inventor
Robert Mark HOFMEYR
Original Assignee
Hofmeyr Robert Mark
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 Hofmeyr Robert Mark filed Critical Hofmeyr Robert Mark
Publication of WO2015063731A1 publication Critical patent/WO2015063731A1/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
    • F24D19/00—Details
    • F24D19/10—Arrangement or mounting of control or safety devices
    • F24D19/1006—Arrangement or mounting of control or safety devices for water heating systems
    • F24D19/1009—Arrangement or mounting of control or safety devices for water heating systems for central heating
    • F24D19/1042—Arrangement or mounting of control or safety devices for water heating systems for central heating the system uses solar energy
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
    • F24D17/00—Domestic hot-water supply systems
    • F24D17/0036—Domestic hot-water supply systems with combination of different kinds of heating means
    • F24D17/0063—Domestic hot-water supply systems with combination of different kinds of heating means solar energy and conventional heaters
    • F24D17/0068—Domestic hot-water supply systems with combination of different kinds of heating means solar energy and conventional heaters with accumulation of the heated water
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H15/00—Control of fluid heaters
    • F24H15/10—Control of fluid heaters characterised by the purpose of the control
    • F24H15/172—Scheduling based on user demand, e.g. determining starting point of heating
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H15/00—Control of fluid heaters
    • F24H15/10—Control of fluid heaters characterised by the purpose of the control
    • F24H15/174—Supplying heated water with desired temperature or desired range of temperature
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H15/00—Control of fluid heaters
    • F24H15/20—Control of fluid heaters characterised by control inputs
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H15/00—Control of fluid heaters
    • F24H15/20—Control of fluid heaters characterised by control inputs
    • F24H15/212—Temperature of the water
    • F24H15/223—Temperature of the water in the water storage tank
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H15/00—Control of fluid heaters
    • F24H15/30—Control of fluid heaters characterised by control outputs; characterised by the components to be controlled
    • F24H15/335—Control of pumps, e.g. on-off control
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H15/00—Control of fluid heaters
    • F24H15/30—Control of fluid heaters characterised by control outputs; characterised by the components to be controlled
    • F24H15/355—Control of heat-generating means in heaters
    • F24H15/37—Control of heat-generating means in heaters of electric heaters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H15/00—Control of fluid heaters
    • F24H15/40—Control of fluid heaters characterised by the type of controllers
    • F24H15/414—Control of fluid heaters characterised by the type of controllers using electronic processing, e.g. computer-based
    • F24H15/45—Control of fluid heaters characterised by the type of controllers using electronic processing, e.g. computer-based remotely accessible
    • F24H15/479—Control of fluid heaters characterised by the type of controllers using electronic processing, e.g. computer-based remotely accessible for programming the system
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24S—SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS
    • F24S50/00—Arrangements for controlling solar heat collectors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
    • F24D2200/00—Heat sources or energy sources
    • F24D2200/02—Photovoltaic energy
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
    • F24D2200/00—Heat sources or energy sources
    • F24D2200/14—Solar energy
    • 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
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B10/00—Integration of renewable energy sources in buildings
    • Y02B10/20—Solar thermal
    • 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
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B10/00—Integration of renewable energy sources in buildings
    • Y02B10/70—Hybrid systems, e.g. uninterruptible or back-up power supplies integrating renewable energies
    • 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
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/40—Solar thermal energy, e.g. solar towers

Definitions

  • This invention relates to a solar water heater controller and, more particularly, it relates to solar water heating systems of the type which include a hot water storage tank and a solar water heating panel for heating water held within the storage tank.
  • solar water heating panel as used herein includes all different forms of solar heating panels including those having, in particular, formed plastic heat collecting panels; generally glazed, flat plate heat collecting panels and evacuated tube heat collectors.
  • the simplest solar water heaters generally comprise a hot water storage tank at the upper end of an upwardly inclined solar water heating panel and hot water can be drawn off from the storage tank as and when required.
  • the solar water heating panel is typically supported on the exterior of the roof of a building in an inclined orientation, using a stand if necessary, so that it is directed generally towards the sun and preferably towards a median seasonal direction of the solar noontime position of the sun.
  • it is generally regarded as aesthetically unacceptable in many applications for the storage tank to be thus visible and the tendency has been to mount the hot water storage tank inside the building, typically within the ceiling space beneath the roof or in a utilities room or closet.
  • the storage tank may be below the level of the upper end of the inclined solar water heating panel and a pump may be installed to provide the required circulation of water.
  • solar water heaters have significantly increased in efficiency and therefore in popularity, they still suffer from various deficiencies.
  • solar water heaters in order to be capable of providing heated water throughout the day, solar water heaters generally include a connection to a conventional power grid which permits the water to be heated during times when there is no or very little solar radiation available.
  • solar water heaters In order to facilitate this procedure, solar water heaters generally include a controller which utilizes a timer and which is capable of activating the connection to the power grid so that water is heated utilizing the solar water heating panel during daylight hours and from the power grid in the late afternoon and early morning. The specific times may be varied for different usage requirements.
  • timers require seasonal adjustment due to variations in day light exposure and temperature from season to season.
  • inclusion of a timer does not provide for cloudy days, in which case only a minimum amount of energy may be generated by the solar water heating panel.
  • the continuous adjustment of timers may result in frustration of users, who, in order to ensure continuous provision of hot water, may adjust the timer so that power is drawn from the power grid at times when the water could adequately be heated by the sun.
  • a solar water heater controller for use in a solar water heater assembly of the type which includes a solar water heating panel for heating water utilizing solar energy, and a hot water storage tank having an auxiliary heating element coupled to a power grid for supplementing the solar water heating panel, wherein the controller has an optionally separate solar radiation detection sensor with which it is capable of communicating in use, wherein the controller is configured to:
  • the controller and solar radiation detection sensor have connections that enable them to communicate over a wired communications channel in use.
  • the controller and solar radiation detection sensor each include a wireless communications module to enable communication over a wireless communications channel.
  • the solar radiation detection sensor and controller are capable of communicating via short range wireless communication, local wireless network, third generation (3G), fourth generation (4G), high-speed downlink packet access (HSDPA), general packet radio service (GPRS), short message service (SMS), and unstructured supplementary service data (USSD) communication protocols or the like.
  • the solar radiation detection sensor includes a photovoltaic module capable of provide electricity to the communications module as well as detecting the intensity of solar radiation available to the solar water heating panel.
  • the hot water storage tank to include a temperature sensor capable of determining the water temperature within the hot water storage tank; for the controller to be capable of communicating with the temperature sensor over a wired or wireless communications channel; for the controller to be configured to receive temperature data from the temperature sensor representative of the water temperature in the hot water storage tank; and for the controller to be configured to utilize the received temperature data in its determination of whether to activate or deactivate the auxiliary heating element.
  • the solar radiation detection sensor to be any one of a photovoltaic module, a thermopile, a pyrgeometer, a pyranometer, a phyheliometer or the like.
  • the controller to include an override switch; for the override switch to enable overriding of the controller so as to activate the auxiliary heating element when the controller has deactivated the auxiliary heating element based on the determination that sufficient solar radiation is available; and for the override switch to deactivate after a specific period of time or when the water temperature in the hot water tank has reached a pre-set level as recorded by the temperature sensor.
  • a solar water heater assembly comprising:
  • a solar water heating panel for heating water utilizing solar energy
  • an auxiliary heating element located in a hot water storage tank for supplementing the solar water heating panel in heating the water, the auxiliary heating element operatively being coupled to a power grid;
  • a controller for selectively activating or deactivating the auxiliary heating element the controller being capable of communicating with a solar radiation detection sensor configured to detect the intensity of solar radiation available to the solar water heating panel and to transmit data representative of the intensity of solar radiation sensed to the controller, and wherein the controller is configured to determine, based at least partially on the received data, whether sufficient solar radiation is available to heat the water in the hot water storage tank utilizing only the solar water heating panel, and, based on the determination, to activate the auxiliary heating element when insufficient solar radiation is available.
  • the controller and solar radiation detection sensor communicate over a wired communications channel.
  • the controller and solar radiation detection sensor each include a wireless communications module to enable communicate over a wireless communications channel as defined above.
  • FIG. 1 is a schematic illustration of one embodiment of a solar water heater assembly according to the invention.
  • FIG. 2 is a flow diagram illustrating a method of heating water utilizing the solar water heater assembly illustrated in Figure 1 .
  • a solar water heater assembly (10) includes a solar water heating panel (12), in this embodiment a multi-evacuated tube type of panel.
  • a solar water heating panel (12) has a number of upwardly inclined parallel evacuated heat absorbing tubes (14) that are interconnected at their upper ends by a heat exchange unit or manifold (16).
  • the manifold (16) is connected to a lower region of a hot water storage tank (18) by means of a feed pipe (20).
  • the feed pipe (20) includes an electrically operated circulation pump (22) to pump water from the cooler lower region of the hot water storage tank (18) into the manifold (16) so that the water can be heated by the heat absorbing tubes (14).
  • an outlet pipe (24) connects the manifold (16) with an upper region of the hot water storage tank (18) so that water heated by the solar water heating panel (12) can be pumped into the upper region of the hot water storage tank (18).
  • the solar water heater assembly (10) includes an auxiliary heating element (26), in this embodiment a conventional electrical water heater coil that is located in the hot water storage tank and which is coupled to a power grid (28).
  • the assembly (10) further includes a controller (30) which is connected to the circulation pump (22) and the auxiliary heating element (26).
  • the controller (30) in this embodiment of the invention, is a programmable microcontroller, and is programmed to activate or deactivate both the circulation pump (22) and the auxiliary heating element (26).
  • the controller (30) is further enabled to communicate with a solar radiation detection sensor (32) that is preferably located in close proximity to the solar water heating panel (12).
  • the sensor (32) in this embodiment, comprises a photovoltaic module (34) and a wireless communications module (36). Wireless communication between the wireless communication module (36) and the controller may take place over any form of wireless communication channel as indicated above.
  • the sensor (32) is capable of determining the solar radiation available to the solar water heating panel (12) and to transmit data representative of the intensity of solar radiation to the controller (30).
  • the controller (30) is configured to receive the data from the sensor (32) and to determine, based at least partially on the received data, whether sufficient solar radiation is available to heat the water in the hot water storage tank (18) utilizing only the solar water heating panel (12). If the controller (30) determines that sufficient solar radiation is available, then only the solar water heating panel (12) will be used to heat the water.
  • the controller (30) may periodically activate the circulation pump (22) so as to pump generally cooler water from the lower region of the hot water storage tank (18) to the solar water heating panel (12) to be heated by the heat absorbing tubes (14) and, once heated, to the upper region of the hot water storage tank (18).
  • the controller (30) determines that insufficient solar radiation is available to heat the water, then the controller (30) activates the auxiliary heating element (26) to assist the solar water heating panel (12) in heating the water. It will be appreciated that where no solar radiation is available, such as during the night, the controller (30) will determine that insufficient solar radiation is available and may then activate the auxiliary heating element (26) as will be described further below.
  • the controller (30) may further be programmed to base its determination of whether to activate the auxiliary heating element (26) on a variety of usage types or user requirement.
  • the controller (30) could be programmed to have three different user settings, such as economical, average and comfort, as well as specified heating times at which hot water will be required by a user. Based on these settings together with the data representative of the solar radiation available to the solar water heating panel (12) the controller would determine whether to activate the auxiliary heating element (26) or not.
  • the economical setting if less than 15 minutes of sufficient solar radiation has occurred on any given day prior to 2 pm, then only will the controller (30) activate the auxiliary heating element.
  • the controller (30) will activate the auxiliary heating element (26).
  • the controller (30) is capable of communicating with a temperature sensor (38) capable of measuring the temperature of the water in the hot water storage tank (18).
  • the controller (30) and temperature sensor (38) communicate over a wired communications channel (40).
  • a wireless communications channel is also possible, in which case the temperature sensor (38) includes a wireless communications module.
  • a user can program the controller (30) with a desired water temperature and the controller (30) then utilizes the water temperature measured by the temperature sensor (38) as well as the data representative of the solar radiation information determined by the solar radiation detection sensor (32) to determine whether sufficient solar radiation is available to heat the water in the hot water storage tank (18) to the projected desired temperature. As mentioned above, if insufficient solar radiation is available, the controller (30) will activate the auxiliary heating element (26) to supplement the solar water heating panel (12) with the heating. Also, once the temperature sensor (38) has determined that the water has been heated to the projected desired temperature, the controller (30) will deactivate the auxiliary heating element (26) so as not to heat the water beyond the projected desired temperature.
  • the temperature sensor (38) will measure this drop in temperature, communicate it to the controller (30) which will then determine whether sufficient solar radiation is available to heat the water to the projected desired temperature utilizing only the solar water heating panel (12) or whether the auxiliary heating element (26) will require to be switched on to supplement the solar water heating panel (12).
  • the controller (30) may be programmed to determine that once communication from the sensor (32) ceases, that no or insufficient solar radiation is available to heat the water utilizing the solar water heating panel, in which case, depending on how the controller (30) is programmed, the controller may activate the auxiliary heating element (26).
  • the photovoltaic module (34) can be utilized to determine the intensity of solar radiation available.
  • FIG. 2 A method of utilizing a solar water heater assembly (1 ) in accordance with the invention is illustrated in Figure 2.
  • the controller (30) determines whether sufficient solar radiation is available to heat the water utilizing only the solar water heating panel (12). During the night, the controller (30) determines that no solar radiation is available as the solar radiation detection sensor (32) has ceased to communicate with the controller (30). As described above, since the communications module (36) is powered by the photovoltaic module (34), no communication will be possible when no solar radiation is available. If insufficient solar radiation is available, then at a next stage (102), the controller (30) determines whether to activate the auxiliary heating element (26) based on the programmed settings..
  • the controller (30) activates the auxiliary heating element (26) to heat the water.
  • the controller (30) can be programmed so that there will be hot water in the hot water storage tank (18) at a specific time, for example 6 am, which will cause the controller (30) to activate the auxiliary heating element at about 4 am.
  • the temperature sensor (38) determines that the water has been heated to the pre-set desired temperature, then at a next step (106), it communicates the measured temperature to the controller (30) which then deactivates the auxiliary heating element (26). The heated water may then be used by a user.
  • the photovoltaic module (34) senses that solar radiation is available and it provides electricity to the wireless communications module (36), which then communicates the intensity of the solar radiation available to the controller (30).
  • the controller (30) determines based on the intensity of solar radiation as well as the temperature of the water in the hot water storage tank (18) and settings programmed on the controller (30) whether sufficient solar radiation is available to heat the water in the hot water storage tank (18) utilizing only the solar water heating panel (12), or whether the auxiliary heating element (26) needs to be activated. If the controller (30) determines that insufficient solar radiation is available, then at a next step (104), the controller (30) activates the auxiliary heating element (26).
  • the controller (30) determines that sufficient solar radiation is available, then at a next step (1 106), the controller (30) activates the circulation pump (22) to pump water to the solar water heating panel (12) and deactivates the auxiliary heating element (26).
  • the controller and solar radiation detection sensor could communicate with each other over a wired connection.
  • any form of solar water heating panel could be used, including integral collector storage (ICS) or batch collectors, flat plate collectors, unglazed or formed collectors or the like.
  • the solar radiation detection sensor could utilize any one of a thermopile, a pyrgeometer, a pyranometer, a phyheliometer or the like to detect the solar radiation.
  • the controller may be programmed in a variety of ways including, for example, to provide for a delay in activating the auxiliary heating element when insufficient solar radiation is available. The delay will ensure that the auxiliary heating element is not activated simply when a cloud or other obstruction overshadows the sensor for a period of time.
  • the controller (30) may also include an override switch (42) which enables overriding of the controller (30) and activating of the auxiliary heating element (26) when the controller (30) has determined that sufficient solar radiation is available to heat the water utilizing only the solar water heating panel (12). Where the controller (30) determines that sufficient solar radiation is available, and therefore deactivates the auxiliary heating element (26), a user could override the controller (30) and simply activate the auxiliary heating element (26) by utilizing the override switch (42).
  • an override switch (42) which enables overriding of the controller (30) and activating of the auxiliary heating element (26) when the controller (30) has determined that sufficient solar radiation is available to heat the water utilizing only the solar water heating panel (12).
  • the override switch (42) is simply a button on the controller (30) which may be pushed to override the controller (30), however, it will be appreciated that the override switch could also be separate from the controller (30) and communicate with the controller (30) over a wired or wireless communications cannel. Activation of the override switch (42) will result in the auxiliary heating element (26) heating the water in the hot water storage tank (18) until the water has reached the pre-set desired temperature, which is then sensed by the temperature sensor (38) and either the controller (30) deactivates the auxiliary heating element (26), or the temperature sensor (38) deactivates the auxiliary heating element (26).
  • the override switch (42) may of course also deactivate the auxiliary heating element (26) after a pre-set period of time. It will be appreciated that the override switch (42) will be particularly useful where, although sufficient solar radiation is available, a user requires that the water is heated at a faster rate, for example, where the user requires hot water within the next hour but the controller has determined that sufficient solar radiation is available, but which heating will take longer than one hour. It may also be possible to override controller (30) by simply switching the electricity to the auxiliary heating element (26) off and on again.
  • the controller determines whether to activate or deactivate the auxiliary heating element based on the amount of solar radiation available to the solar water heating panel, the assembly will utilize close to the optimum amount of both solar radiation and electricity to ensure that the water within the hot water storage tank will achieve the preset desired temperature.
  • no seasonal adjustments will have to be made to the controller as activation of the auxiliary heating element is dependent on the availability of solar radiation instead of the length of a day or the like.
  • Conventional solar water heater assemblies that utilize timers to activate the auxiliary heating element are generally set to activate the element between 4 and 6 pm so as to ensure that sufficient hot water is available at night, while utilizing most of the solar radiation available during the day. Furthermore, by activating the auxiliary heating element during those time periods, the assembly will ensure that sufficient hot water is available even on a cloudy day. Nevertheless, on a sunny day, unless the water temperature in the hot water storage tank has reached the desired temperature, the auxiliary heating element will activate even though sufficient solar radiation is available to heat the water.
  • the assembly of the present invention on the other hand will be able to determine whether sufficient solar radiation is available to heat the water to the desired temperature, and if available, will utilize the solar water heater panel to heat the water instead of the auxiliary heating element.
  • timers used for conventional solar water heating assemblies may be inaccurate over time, thereby causing auxiliary heating elements to heat water during times when more than enough solar radiation is available to heat the water.
  • this problem is of no relevance since the controller continuously determines whether sufficient solar radiation is available and activation of the auxiliary heating element is based on such a determination.
  • the controller can determine the average sunrise and sunset times over a period of time, it can reset an internal clock or timer to correct gross errors.
  • a conventional timer may over time be grossly incorrect, for example heating water between 8 and 10 am instead of 4 and 6 am, thereby not providing hot water when it is needed and utilizing electricity although sufficient solar radiation is available.
  • the controller of the present invention is enabled to determine the average sunrise and sunset times and adjust its internal clock accordingly, thus circumventing this problem.
  • the wireless communications signal could be utilized by an electricity provider to transmit signals to all controllers in a given area to not utilize electricity for the auxiliary heating element. For example, if the electricity provider experiences problems to provide sufficient electricity for a given area, the provider could simply send a signal to all controllers that sufficient solar radiation is available and the controllers would then simply deactivate the auxiliary heating elements, hence reducing the load on the provider.
  • the controller could simply be installed in the electricity distribution board of a premises, or the controller and solar radiation detection sensor could form a single device which is installed adjacent the solar water heating panel. Alternatively, the controller could be installed on the electrical conductor between the solar water heater isolator and solar water heater element.
  • the controller could be sold as a standalone device which can be retrofitted to an existing solar water heater assembly by simply removing the existing controller and replacing it with the controller of the present invention. Nevertheless, the controller could also be installed in addition to an existing timer.
  • controller could be utilized for any type of solar water heater assembly and the functioning thereof would be the same irrespective of whether the assembly is a direct or open loop assembly in which water is circulated through the collectors or an indirect or closed loop assembly in which an anti-freeze fluid runs through the collectors and a heat exchanger is used to derive the heat from the fluid.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Computer Hardware Design (AREA)
  • Heat-Pump Type And Storage Water Heaters (AREA)

Abstract

A solar water heater controller (30) is provided. The controller (30) may be used in a solar water heater assembly (1 ) that includes a solar water heating panel (12) for heating water utilising solar energy, a hot water storage tank (1 8) and an auxiliary heating element (26) coupled to a power grid (28) for supplementing the solar water heating panel (12). The controller (30) includes a solar radiation detection sensor (32) which is capable of detecting the intensity of solar radiation available to the solar water heating panel (12) and to transmit data representative of the intensity of solar radiation to the controller (30). The controller (30) is configured to determine, based on the received data, whether sufficient solar radiation is available to the heat water in the hot water storage tank (18) utilising only the solar water heating panel (12) and, if insufficient solar radiation is available, to activate the auxiliary heating element (26) so as to supplement the solar water heating panel (12).

Description

A SOLAR WATER HEATER CONTROLLER
CROSS-REFERENCE TO RELATED APPLICATION This application claims priority to South African provisional patent application number 2013/08124, which is incorporated herein.
FIELD OF THE INVENTION This invention relates to a solar water heater controller and, more particularly, it relates to solar water heating systems of the type which include a hot water storage tank and a solar water heating panel for heating water held within the storage tank. It is to be understood that the term solar water heating panel as used herein includes all different forms of solar heating panels including those having, in particular, formed plastic heat collecting panels; generally glazed, flat plate heat collecting panels and evacuated tube heat collectors. BACKGROUND TO THE INVENTION
The simplest solar water heaters generally comprise a hot water storage tank at the upper end of an upwardly inclined solar water heating panel and hot water can be drawn off from the storage tank as and when required. The solar water heating panel is typically supported on the exterior of the roof of a building in an inclined orientation, using a stand if necessary, so that it is directed generally towards the sun and preferably towards a median seasonal direction of the solar noontime position of the sun. However, it is generally regarded as aesthetically unacceptable in many applications for the storage tank to be thus visible and the tendency has been to mount the hot water storage tank inside the building, typically within the ceiling space beneath the roof or in a utilities room or closet. In such instances the storage tank may be below the level of the upper end of the inclined solar water heating panel and a pump may be installed to provide the required circulation of water.
Although solar water heaters have significantly increased in efficiency and therefore in popularity, they still suffer from various deficiencies. For example, in order to be capable of providing heated water throughout the day, solar water heaters generally include a connection to a conventional power grid which permits the water to be heated during times when there is no or very little solar radiation available. In order to facilitate this procedure, solar water heaters generally include a controller which utilizes a timer and which is capable of activating the connection to the power grid so that water is heated utilizing the solar water heating panel during daylight hours and from the power grid in the late afternoon and early morning. The specific times may be varied for different usage requirements.
However, in order to maintain effectiveness of such solar water heaters, the timers require seasonal adjustment due to variations in day light exposure and temperature from season to season. Furthermore, the inclusion of a timer does not provide for cloudy days, in which case only a minimum amount of energy may be generated by the solar water heating panel. The continuous adjustment of timers may result in frustration of users, who, in order to ensure continuous provision of hot water, may adjust the timer so that power is drawn from the power grid at times when the water could adequately be heated by the sun.
SUMMARY OF THE INVENTION In accordance with a first aspect of the invention there is provided a solar water heater controller for use in a solar water heater assembly of the type which includes a solar water heating panel for heating water utilizing solar energy, and a hot water storage tank having an auxiliary heating element coupled to a power grid for supplementing the solar water heating panel, wherein the controller has an optionally separate solar radiation detection sensor with which it is capable of communicating in use, wherein the controller is configured to:
receive, from the solar radiation detection sensor, data representative of an intensity of solar radiation sensed by the solar radiation detection sensor and available to the solar water heating panel;
determine, based on data received, whether sufficient solar radiation is available to heat water utilizing only the solar water heating panel; and
if insufficient solar radiation is available, to operate a circuit that in use enables the auxiliary heating element to supplement the solar water heating panel. In one embodiment, the controller and solar radiation detection sensor have connections that enable them to communicate over a wired communications channel in use.
In an alternative embodiment, the controller and solar radiation detection sensor each include a wireless communications module to enable communication over a wireless communications channel. In this embodiment, the solar radiation detection sensor and controller are capable of communicating via short range wireless communication, local wireless network, third generation (3G), fourth generation (4G), high-speed downlink packet access (HSDPA), general packet radio service (GPRS), short message service (SMS), and unstructured supplementary service data (USSD) communication protocols or the like. In this embodiment the solar radiation detection sensor includes a photovoltaic module capable of provide electricity to the communications module as well as detecting the intensity of solar radiation available to the solar water heating panel. Further features of the invention provide for the hot water storage tank to include a temperature sensor capable of determining the water temperature within the hot water storage tank; for the controller to be capable of communicating with the temperature sensor over a wired or wireless communications channel; for the controller to be configured to receive temperature data from the temperature sensor representative of the water temperature in the hot water storage tank; and for the controller to be configured to utilize the received temperature data in its determination of whether to activate or deactivate the auxiliary heating element.
Yet further features of the invention provide for the solar radiation detection sensor to be any one of a photovoltaic module, a thermopile, a pyrgeometer, a pyranometer, a phyheliometer or the like. Still further features of the invention provide for the controller to include an override switch; for the override switch to enable overriding of the controller so as to activate the auxiliary heating element when the controller has deactivated the auxiliary heating element based on the determination that sufficient solar radiation is available; and for the override switch to deactivate after a specific period of time or when the water temperature in the hot water tank has reached a pre-set level as recorded by the temperature sensor.
In accordance with a second aspect of the invention there is provided a solar water heater assembly comprising:
a solar water heating panel for heating water utilizing solar energy; an auxiliary heating element located in a hot water storage tank for supplementing the solar water heating panel in heating the water, the auxiliary heating element operatively being coupled to a power grid; and
a controller for selectively activating or deactivating the auxiliary heating element, the controller being capable of communicating with a solar radiation detection sensor configured to detect the intensity of solar radiation available to the solar water heating panel and to transmit data representative of the intensity of solar radiation sensed to the controller, and wherein the controller is configured to determine, based at least partially on the received data, whether sufficient solar radiation is available to heat the water in the hot water storage tank utilizing only the solar water heating panel, and, based on the determination, to activate the auxiliary heating element when insufficient solar radiation is available.
In one embodiment of the second aspect of the invention, the controller and solar radiation detection sensor communicate over a wired communications channel.
In an alternative embodiment of the second aspect of the invention, the controller and solar radiation detection sensor each include a wireless communications module to enable communicate over a wireless communications channel as defined above.
Other features of the second aspect of the invention are as defined above in relation to the controller itself. BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described, by way of example only with reference to the accompanying representations in which: Figure 1 is a schematic illustration of one embodiment of a solar water heater assembly according to the invention; and
Figure 2 is a flow diagram illustrating a method of heating water utilizing the solar water heater assembly illustrated in Figure 1 . DETAILED DESCRIPTION WITH REFERENCE TO THE DRAWINGS
In the embodiment of the invention illustrated schematically in Figure 1 , a solar water heater assembly (10) includes a solar water heating panel (12), in this embodiment a multi-evacuated tube type of panel. Such a solar water heating panel (12) has a number of upwardly inclined parallel evacuated heat absorbing tubes (14) that are interconnected at their upper ends by a heat exchange unit or manifold (16). The manifold (16) is connected to a lower region of a hot water storage tank (18) by means of a feed pipe (20). The feed pipe (20) includes an electrically operated circulation pump (22) to pump water from the cooler lower region of the hot water storage tank (18) into the manifold (16) so that the water can be heated by the heat absorbing tubes (14). Further, an outlet pipe (24) connects the manifold (16) with an upper region of the hot water storage tank (18) so that water heated by the solar water heating panel (12) can be pumped into the upper region of the hot water storage tank (18).
In addition to the solar water heating panel (12), the solar water heater assembly (10) includes an auxiliary heating element (26), in this embodiment a conventional electrical water heater coil that is located in the hot water storage tank and which is coupled to a power grid (28).
The assembly (10) further includes a controller (30) which is connected to the circulation pump (22) and the auxiliary heating element (26). The controller (30), in this embodiment of the invention, is a programmable microcontroller, and is programmed to activate or deactivate both the circulation pump (22) and the auxiliary heating element (26). The controller (30) is further enabled to communicate with a solar radiation detection sensor (32) that is preferably located in close proximity to the solar water heating panel (12). The sensor (32), in this embodiment, comprises a photovoltaic module (34) and a wireless communications module (36). Wireless communication between the wireless communication module (36) and the controller may take place over any form of wireless communication channel as indicated above.
The sensor (32) is capable of determining the solar radiation available to the solar water heating panel (12) and to transmit data representative of the intensity of solar radiation to the controller (30). The controller (30) is configured to receive the data from the sensor (32) and to determine, based at least partially on the received data, whether sufficient solar radiation is available to heat the water in the hot water storage tank (18) utilizing only the solar water heating panel (12). If the controller (30) determines that sufficient solar radiation is available, then only the solar water heating panel (12) will be used to heat the water. In this case, the controller (30) may periodically activate the circulation pump (22) so as to pump generally cooler water from the lower region of the hot water storage tank (18) to the solar water heating panel (12) to be heated by the heat absorbing tubes (14) and, once heated, to the upper region of the hot water storage tank (18).
On the other hand, if the controller (30) determines that insufficient solar radiation is available to heat the water, then the controller (30) activates the auxiliary heating element (26) to assist the solar water heating panel (12) in heating the water. It will be appreciated that where no solar radiation is available, such as during the night, the controller (30) will determine that insufficient solar radiation is available and may then activate the auxiliary heating element (26) as will be described further below.
The controller (30) may further be programmed to base its determination of whether to activate the auxiliary heating element (26) on a variety of usage types or user requirement. For example, the controller (30) could be programmed to have three different user settings, such as economical, average and comfort, as well as specified heating times at which hot water will be required by a user. Based on these settings together with the data representative of the solar radiation available to the solar water heating panel (12) the controller would determine whether to activate the auxiliary heating element (26) or not. Thus for example, in the economical setting, if less than 15 minutes of sufficient solar radiation has occurred on any given day prior to 2 pm, then only will the controller (30) activate the auxiliary heating element. Alternatively, in the average setting, if less than 30 minutes of sufficient solar radiation has occurred on any given day prior to 12 pm, then the controller (30) will activate the auxiliary heating element (26).
In addition and to assist the controller (30) in determining whether to activate or deactivate the auxiliary heating element (26), the controller (30) is capable of communicating with a temperature sensor (38) capable of measuring the temperature of the water in the hot water storage tank (18). In this embodiment, the controller (30) and temperature sensor (38) communicate over a wired communications channel (40). However, a wireless communications channel is also possible, in which case the temperature sensor (38) includes a wireless communications module.
A user can program the controller (30) with a desired water temperature and the controller (30) then utilizes the water temperature measured by the temperature sensor (38) as well as the data representative of the solar radiation information determined by the solar radiation detection sensor (32) to determine whether sufficient solar radiation is available to heat the water in the hot water storage tank (18) to the projected desired temperature. As mentioned above, if insufficient solar radiation is available, the controller (30) will activate the auxiliary heating element (26) to supplement the solar water heating panel (12) with the heating. Also, once the temperature sensor (38) has determined that the water has been heated to the projected desired temperature, the controller (30) will deactivate the auxiliary heating element (26) so as not to heat the water beyond the projected desired temperature. Should the water temperature then drop, for example due to usage of hot water, the temperature sensor (38) will measure this drop in temperature, communicate it to the controller (30) which will then determine whether sufficient solar radiation is available to heat the water to the projected desired temperature utilizing only the solar water heating panel (12) or whether the auxiliary heating element (26) will require to be switched on to supplement the solar water heating panel (12).
It will be appreciated that due to the solar radiation detection sensor (32) including a photovoltaic module (34), no additional power source will be required to enable the sensor (32) to utilize the wireless communications module (36). Further, since the module is powered by the photovoltaic module (34), the controller (30) may be programmed to determine that once communication from the sensor (32) ceases, that no or insufficient solar radiation is available to heat the water utilizing the solar water heating panel, in which case, depending on how the controller (30) is programmed, the controller may activate the auxiliary heating element (26). In addition to providing electricity for the wireless communications module (36), the photovoltaic module (34) can be utilized to determine the intensity of solar radiation available.
A method of utilizing a solar water heater assembly (1 ) in accordance with the invention is illustrated in Figure 2. At a first step (100), the controller (30) determines whether sufficient solar radiation is available to heat the water utilizing only the solar water heating panel (12). During the night, the controller (30) determines that no solar radiation is available as the solar radiation detection sensor (32) has ceased to communicate with the controller (30). As described above, since the communications module (36) is powered by the photovoltaic module (34), no communication will be possible when no solar radiation is available. If insufficient solar radiation is available, then at a next stage (102), the controller (30) determines whether to activate the auxiliary heating element (26) based on the programmed settings.. If the settings require that water should be heated, then at a next stage (104) the controller (30) activates the auxiliary heating element (26) to heat the water. As described above, the controller (30) can be programmed so that there will be hot water in the hot water storage tank (18) at a specific time, for example 6 am, which will cause the controller (30) to activate the auxiliary heating element at about 4 am. Once the temperature sensor (38) determines that the water has been heated to the pre-set desired temperature, then at a next step (106), it communicates the measured temperature to the controller (30) which then deactivates the auxiliary heating element (26). The heated water may then be used by a user. Once the sun rises, then at a step (100), the photovoltaic module (34) senses that solar radiation is available and it provides electricity to the wireless communications module (36), which then communicates the intensity of the solar radiation available to the controller (30). The controller (30) then determines based on the intensity of solar radiation as well as the temperature of the water in the hot water storage tank (18) and settings programmed on the controller (30) whether sufficient solar radiation is available to heat the water in the hot water storage tank (18) utilizing only the solar water heating panel (12), or whether the auxiliary heating element (26) needs to be activated. If the controller (30) determines that insufficient solar radiation is available, then at a next step (104), the controller (30) activates the auxiliary heating element (26). Alternatively, if the controller (30) determines that sufficient solar radiation is available, then at a next step (1 106), the controller (30) activates the circulation pump (22) to pump water to the solar water heating panel (12) and deactivates the auxiliary heating element (26). It will be appreciated that many other embodiments of solar water heater assemblies exist which fall within the scope of the invention. For example, the controller and solar radiation detection sensor could communicate with each other over a wired connection. Also, any form of solar water heating panel could be used, including integral collector storage (ICS) or batch collectors, flat plate collectors, unglazed or formed collectors or the like. Further, the solar radiation detection sensor could utilize any one of a thermopile, a pyrgeometer, a pyranometer, a phyheliometer or the like to detect the solar radiation.
Also, and as described above, the controller may be programmed in a variety of ways including, for example, to provide for a delay in activating the auxiliary heating element when insufficient solar radiation is available. The delay will ensure that the auxiliary heating element is not activated simply when a cloud or other obstruction overshadows the sensor for a period of time.
In addition, the controller (30) may also include an override switch (42) which enables overriding of the controller (30) and activating of the auxiliary heating element (26) when the controller (30) has determined that sufficient solar radiation is available to heat the water utilizing only the solar water heating panel (12). Where the controller (30) determines that sufficient solar radiation is available, and therefore deactivates the auxiliary heating element (26), a user could override the controller (30) and simply activate the auxiliary heating element (26) by utilizing the override switch (42). In the embodiment illustrated, the override switch (42) is simply a button on the controller (30) which may be pushed to override the controller (30), however, it will be appreciated that the override switch could also be separate from the controller (30) and communicate with the controller (30) over a wired or wireless communications cannel. Activation of the override switch (42) will result in the auxiliary heating element (26) heating the water in the hot water storage tank (18) until the water has reached the pre-set desired temperature, which is then sensed by the temperature sensor (38) and either the controller (30) deactivates the auxiliary heating element (26), or the temperature sensor (38) deactivates the auxiliary heating element (26). The override switch (42) may of course also deactivate the auxiliary heating element (26) after a pre-set period of time. It will be appreciated that the override switch (42) will be particularly useful where, although sufficient solar radiation is available, a user requires that the water is heated at a faster rate, for example, where the user requires hot water within the next hour but the controller has determined that sufficient solar radiation is available, but which heating will take longer than one hour. It may also be possible to override controller (30) by simply switching the electricity to the auxiliary heating element (26) off and on again.
Further, it will be appreciated that because the controller determines whether to activate or deactivate the auxiliary heating element based on the amount of solar radiation available to the solar water heating panel, the assembly will utilize close to the optimum amount of both solar radiation and electricity to ensure that the water within the hot water storage tank will achieve the preset desired temperature. In addition, no seasonal adjustments will have to be made to the controller as activation of the auxiliary heating element is dependent on the availability of solar radiation instead of the length of a day or the like.
Conventional solar water heater assemblies that utilize timers to activate the auxiliary heating element are generally set to activate the element between 4 and 6 pm so as to ensure that sufficient hot water is available at night, while utilizing most of the solar radiation available during the day. Furthermore, by activating the auxiliary heating element during those time periods, the assembly will ensure that sufficient hot water is available even on a cloudy day. Nevertheless, on a sunny day, unless the water temperature in the hot water storage tank has reached the desired temperature, the auxiliary heating element will activate even though sufficient solar radiation is available to heat the water. The assembly of the present invention on the other hand will be able to determine whether sufficient solar radiation is available to heat the water to the desired temperature, and if available, will utilize the solar water heater panel to heat the water instead of the auxiliary heating element.
Furthermore, applicant has found that timers used for conventional solar water heating assemblies may be inaccurate over time, thereby causing auxiliary heating elements to heat water during times when more than enough solar radiation is available to heat the water. With the present system this problem is of no relevance since the controller continuously determines whether sufficient solar radiation is available and activation of the auxiliary heating element is based on such a determination. Also, because the controller can determine the average sunrise and sunset times over a period of time, it can reset an internal clock or timer to correct gross errors. Thus, where a conventional timer may over time be grossly incorrect, for example heating water between 8 and 10 am instead of 4 and 6 am, thereby not providing hot water when it is needed and utilizing electricity although sufficient solar radiation is available. The controller of the present invention is enabled to determine the average sunrise and sunset times and adjust its internal clock accordingly, thus circumventing this problem. In addition, in the event that the solar radiation detection sensor communicates with the controller over a wireless communication channel, the wireless communications signal could be utilized by an electricity provider to transmit signals to all controllers in a given area to not utilize electricity for the auxiliary heating element. For example, if the electricity provider experiences problems to provide sufficient electricity for a given area, the provider could simply send a signal to all controllers that sufficient solar radiation is available and the controllers would then simply deactivate the auxiliary heating elements, hence reducing the load on the provider.
It will be appreciated that the controller could simply be installed in the electricity distribution board of a premises, or the controller and solar radiation detection sensor could form a single device which is installed adjacent the solar water heating panel. Alternatively, the controller could be installed on the electrical conductor between the solar water heater isolator and solar water heater element.
The controller could be sold as a standalone device which can be retrofitted to an existing solar water heater assembly by simply removing the existing controller and replacing it with the controller of the present invention. Nevertheless, the controller could also be installed in addition to an existing timer.
Finally, it will be appreciated that the controller could be utilized for any type of solar water heater assembly and the functioning thereof would be the same irrespective of whether the assembly is a direct or open loop assembly in which water is circulated through the collectors or an indirect or closed loop assembly in which an anti-freeze fluid runs through the collectors and a heat exchanger is used to derive the heat from the fluid.

Claims

CLAIMS:
1 . A solar water heater controller (30) for use in a solar water heater assembly (1 ) of the type which includes a solar water heating panel (12) for heating water utilizing solar energy, and a hot water storage tank (18) having an auxiliary heating element (26) coupled to a power grid (28) for supplementing the solar water heating panel (12), wherein the controller (30) has an optionally separate solar radiation detection sensor (32) with which it is capable of communicating in use, wherein the controller (30) is configured to:
receive, from the solar radiation detection sensor (32), data representative of an intensity of solar radiation sensed by the solar radiation detection sensor (32) and available to the solar water heating panel (12);
determine, based on data received, whether sufficient solar radiation is available to heat water utilizing only the solar water heating panel (12); and
if insufficient solar radiation is available, to operate a circuit that in use enables the auxiliary heating element (26) to supplement the solar water heating panel (12).
2. A solar water heater controller (30) as claimed in claim 1 , wherein the controller (30) and the solar radiation detection sensor (32) have connections that enable them to communicate over a wired communications channel in use.
3. A solar water heater controller (30) as claimed in claim 1 , wherein the controller (30) and the solar radiation detection sensor (32) each include a wireless communications module (36) to enable communication over a wireless communications channel.
4. A solar water heater controller (30) as claimed in claim 3, wherein the solar radiation detection sensor (32) includes a photovoltaic module (36) capable of providing electricity to the wireless communications module (36).
5. A solar water heater controller (30) as claimed in any one of the preceding claims, wherein the hot water storage tank (18) includes a temperature sensor (38) capable of determining the water temperature within the hot water storage tank (18) and for the controller (30) to be capable of communicating with the temperature sensor (38).
6. A solar water heater controller (30) as claimed in claim 5, wherein the controller (30) is configured to receive temperature data from the temperature sensor (38) representative of the water temperature in the hot water storage tank (18) and to utilize the received temperature data in its determination whether to enable the auxiliary heating element (26) to supplement the solar water heating panel (12).
7. A solar water heater controller (30) as claimed in any one of the preceding claims, wherein the controller (30) includes an override switch (42) to enable overriding of the controller (30) thereby closing a circuit and activating the auxiliary heating element (26) when the controller (30) has deactivated the auxiliary heating element (26).
8. A solar water heater controller (30) as claimed in any one of the preceding claims, wherein the solar radiation detection sensor (32) is one of a photovoltaic module, a thermopile, a pyrgeometer, a pyranometer, or a phyheliometer.
9. A solar water heater assembly (1 ) comprising:
a solar water heating panel (12) for heating water utilizing solar energy; an auxiliary heating element (26) located in a hot water storage tank (18) for supplementing the solar water heating panel (12) in heating water, the auxiliary heating element (26) operatively being coupled to a power grid (28); and
a controller (30) for selectively activating or deactivating the auxiliary heating element (26), the controller (30) being capable of communicating with a solar radiation detection sensor (32) configured to detect the intensity of solar radiation available to the solar water heating panel (12) and to transmit data representative of the intensity of solar radiation sensed to the controller (30), and wherein the controller (30) is configured to determine, based at least partially on the received data, whether sufficient solar radiation is available to heat water utilizing only the solar water heating panel (12), and, based on the determination, to activate the auxiliary heating element (26) when insufficient solar radiation is available.
A solar water heater assembly (1 ) as claimed in claim 9, wherein the controller (30) and the solar radiation detection sensor (32) communicate over a wired communications channel.
A solar water heater assembly (1 ) as claimed in claim 9, wherein the controller (30) and the solar radiation detection sensor (32) each include a wireless communications module (36) to enable communication over a wireless communications channel.
A solar water heater assembly (1 ) as claimed in any one of claims 10 to 13, wherein the hot water storage tank (18) includes a temperature sensor (38) capable of communicating with the controller (30) and configured to determine the water temperature within the hot water storage tank (18). A solar water heater assembly (1 ) as claimed in claim 12, wherein the controller (30) is configured to receive temperature data from the temperature sensor (38) representative of the water temperature in the hot water storage tank (18) and to utilize the received temperature data in its determination whether to activate or deactivate the auxiliary heating element (26).
A solar water heater assembly (1 ) as claimed in any one of claims 9 to 13, wherein the controller (30) includes an override switch (42) to enable overriding of the controller (30) thereby closing a circuit and activating the auxiliary heating element (26) when the controller (30) has deactivated the auxiliary heating element (26).
PCT/IB2014/065741 2013-10-31 2014-10-31 A solar water heater controller WO2015063731A1 (en)

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CN116839244A (en) * 2023-09-01 2023-10-03 国网江苏省电力有限公司南京供电分公司 Control method and device for multi-heat source heat pump phase change energy storage combined cooling and heating system

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CN105243235A (en) * 2015-11-05 2016-01-13 中国建筑西南设计研究院有限公司 Heat storage volume determining method for solar hot water heating system
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CN116839244A (en) * 2023-09-01 2023-10-03 国网江苏省电力有限公司南京供电分公司 Control method and device for multi-heat source heat pump phase change energy storage combined cooling and heating system
CN116839244B (en) * 2023-09-01 2023-12-19 国网江苏省电力有限公司南京供电分公司 Control method and device for multi-heat source heat pump phase-change energy storage type cold and heat combined supply system

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