SOLAR POOL HEATER

An automated wirelessly-controlled solar pool heater including a floating water reservoir with active (DC electric) heating, an internal pump assembly, a first temperature sensor for sensing temperature in the water reservoir, a second temperature sensor for sensing ambient pool water, a microcontroller module with wireless transceiver for remote monitoring and operation, and a solar-charging battery. In operation, the pump assembly self-primes and automatically fills the entire water reservoir with pool water. Immersion heating elements inside the reservoir are activated and water in the reservoir begins to heat. Once fully heated to a preset max temperature the microcontroller activates the pump assembly to intermittently expel the heated water back into the pool, simultaneously refilling the water reservoir with unheated pool water. The recirculation program continues until the water temperature of the entire pool reaches its desired temperature.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to pool heaters and, in particular, a floating solar pool heater that employs a solar-charged battery-powered immersion water heater and a wireless-enabled processor for remote pool temperature control.

2. Description of the Background

Water heaters are often used in pools to maintain a comfortable water temperature. There are a variety of different types of pool water heaters. For example, flexible covers made of heat-absorbing materials are used to raise the temperature of the pool water. Unfortunately, pool covers restrict access to the water, are unwieldy and cumbersome to remove and replace, difficult to store, and often sink below the surface of the water.

Solar pool heaters are well-known. Solar heaters typically feed water to stationary solar panels installed nearby. The pool water may be pumped to the solar panels via electric pumps. However, most conventional solar pool heaters are very expensive, large and aesthetically unpleasant, and require substantial effort to install. They are also fairly inefficient due to heat loss in the return lines.

Consequently, there remains a need for a low cost modular high efficiency solar pool heater that can alleviate the disadvantages of the existing solar pool heating systems.

What is needed is a compact and efficient fully-automated and yet remotely controlled solar pool heater.

SUMMARY OF THE INVENTION

According to an embodiment of the invention, an automated wirelessly-controlled solar pool heater is disclosed that includes a floatation vessel carrying a water reservoir with internally-exposed immersion water-heating elements for DC-electric heating of pool water circulated there through, a pump assembly for intermittently pumping water through the water reservoir, and one or more temperature sensors for sensing temperature in the water reservoir and in the pool. A cover fits atop the water reservoir and a solar cell is mounted atop the cover for recharging a battery that powers the pump, heating elements and other electronics. A partition fits inside the flotation vessel, the cover/solar cell fits atop the flotation vessel, and the space between the cover and partition defines the water reservoir. In operation, heating of the water in the water reservoir occurs by exposure with the immersion heating elements. The water is intermittently pumped through the water reservoir by a pump assembly, both the pump assembly and heating elements being powered by a battery bank that is charged by the solar panel. The pool heater is controlled by a microcontroller module with wireless transceiver for remote monitoring and programmed operation. The pump assembly self-primes and automatically fills the entire water reservoir with pool water. Water in the water reservoir begins to heat via the heating elements. Initially it takes 4-6 minutes for the water in water reservoir to reach an optimal temperature, at which point the microcontroller module activates the pump assembly to intermittently expel the entire volume of the heated water residing therein back into the pool, simultaneously refilling the water reservoir with unheated pool water. The recirculation program continues until the water temperature of the entire pool reaches its desired temperature.

The present invention is described in greater detail in the detailed description of the invention, and the appended drawings. Additional features and advantages of the invention will be set forth in the description that follows, will be apparent from the description, or may be learned by using the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

As seen in FIG. 1, the present invention is an automated wirelessly-controlled solar pool heater 2 comprising a floatation vessel 10, and an internal computer-controlled solar-powered pump assembly and battery (to be described) for periodically inducting pool water into an internal water reservoir, heating it via immersion heating elements, and intermittently expelling the heated water back into the pool and inducting new unheated water. An external ON/OFF button initiates one-touch operation.

FIG. 2 is a bottom view of the solar pool heater 2, FIG. 3 is a side view, and FIG. 4 is a side cross-section taken along the line A-A of FIG. 3. With combined reference to FIGS. 2-4 the floatation vessel 10 comprises a buoyant disc-shaped housing with interior circular partition 12 seated inside flotation vessel 10, a cover 24, and a solar cell 60 seated atop cover 24. The area between the cover 24 and partition 12 defines a water reservoir 20 for active DC-electrical heating of water contained therein. The flotation vessel 10 includes a downwardly-protruding compartment 13 with pull-down spout 44 that when deployed protrudes well-beneath the water level for extended water intake and outlet. A separate water-proof housing 14 described below encloses a pump assembly 30, micro-controller chamber 70, and battery bank 50.

The partition 12 includes a central hub 15 that extends a radial-array of immersion heating elements 73 for active (DC electric) heating of the water in reservoir 20.

Referring back to FIG. 1 a solar cell 60 is mounted atop the cover 24. Solar cell 60 is preferably a circular solar cell that substantially spans the cover 24 for maximum efficiency. The cover 24 itself is a disc-shaped cover conforming to flotation vessel 10 and configured for snap-fit or twist-lock insertion thereon, and preferably with a recessed top surface for seating solar cell 60.

FIG. 2 illustrates the spout 44, which is an open-ended tubular member formed with hinge pins 45 at one end journaled into the walls of the bay 13. The spout 44 may be seated flush inside bay 13 or deployed to a downwardly extended position protruding 3-6″ beneath bay 13. Detent clips 46 may be provided to prevent inadvertent deployment. The water intake tube 23 enters the spout 44 at the hinged end. FIG. 2 also illustrates two opposing handles 49 molded into the bottom of the floatation vessel 10 to assist in carrying the solar pool heater 2.

With spout 44 extended, the pump 30 intermittently pumps water into the water reservoir 20 through intake tube 23, where it travels past one of at least two temperature sensors 41, 42 (one internal sensor 41 for sensing temperature in the water reservoir 20 and one external sensor 42 for the temperature of the pool water). A battery bank 50 is connected to the pump 30, to a plurality of immersion heating elements 73 radially-extending into water reservoir 20, to a solar panel 60 for maintaining battery bank 50 charge, and to a microcontroller module 70 with processor, software and wireless transceiver for remote monitoring and programmed operation of solar pool heater 2 as will be described. In operation, when first powered on via on/off button 53 and placed in the pool the pump assembly 30 is self-priming and automatically fills the entire water reservoir 20. In addition to temperature sensors 41, 42, there is a water fill sensor 43 that indicates to microcontroller module 70 when the heating elements 73 are fully submerged in water (so as not to burn them out). Once full, the microcontroller module 70 switches off the pump assembly 30 and polls the water fill sensor 43. If water fill sensor 43 confirms that the heating elements 73 are fully submerged in water, the microcontroller module 70 switches on the heating elements 73, and active heating occurs as the water resident in the water-heating reservoir 20 is exposed to the heating elements 73 therein. Given the active electric heating it initially takes only 4-6 minutes for the water in water reservoir 20 to reach a maximum temperature (e.g., 150 degrees F., calculated as being just below a threshold that burns the skin). Microcontroller module 70 monitors the internal temperature via internal temperature sensor 41, which is imbedded inside the water reservoir 20. Once the temperature of the water in the water reservoir 20 is heated to a preset temperature apex, microcontroller module 70 activates the pump assembly 30 to expel the full volume of the heated water residing in water reservoir 20 back into the pool, simultaneously refilling the water reservoir 20 with unheated pool water.

Water remaining in the water reservoir 20 mixes with the incoming pool water and heats it, allowing the temperature of the preset water in the water reservoir 20 to reach its apex more quickly. The recirculation program continues: each time the water in the water reservoir 20 reaches the preset apex the pump assembly 30 will again flush the full volume of the water, and the cycle continues. Microcontroller module 70 monitors the external temperature via external temperature sensor 42, which is outwardly exposed/embedded in the wall of the floatation vessel 10, and microcontroller module 70 continues to periodically recirculate the water in water reservoir 20 until the water temperature of the pool water as measured at external sensor 42 reaches its desired temperature. The microcontroller module 70 is wirelessly enabled and remotely-programmable by a software application resident on a laptop, smart phone or the like.

Referring to FIG. 5 the solar cell 60 is set into the disc-shaped one-part cover 24 which is in turn affixed atop flotation vessel 10. The circular partition 12 is set inside flotation vessel 10, and the space between partition 12 and cover 24 define the enclosed water reservoir 20. The water reservoir 20 is further subdivided two concentric chambers by a raised annular hub 15 that rises up from partition 12. The area inside hub 15 comprises an active heating chamber 14 and a plurality of heating elements 73 are suspended therein. The heating elements 73 are connected to contact terminals 77 that protrude outside hub 15, and from there are connected on to the microcontroller module 70 and battery bank 50. The entire partition 12 and hub 15 may be integrally formed of metal for heat conduction, so that heat from elements 73 is efficiently conducted into the water which fills the area outside hub 15. The microcontroller 70 selectively applies battery power to the heating elements 73 to actively heat the water inside water reservoir 20.

The circular partition 12 preferably snap-fits or twist-locks inside flotation vessel 10, cover 24 snap-fits or twist-locks atop flotation vessel 10, and solar cell 60 snap-fits or twist-locks inside cover 24, collectively presenting a 24″ diameter unit capable of easy lifting when filled with water. The flotation vessel 10 leaves room at the center beneath partition 12 for a separate water-proof housing 72 containing pump assembly 30, battery bank 50, and microcontroller module 70. The pump assembly 30 includes a pump, preferably a high-efficiency 12V solar water pump such as, for example, a Kamoer™ KLP02 micro diaphragm pump with 12V DC brushless motor calibrated to refill the entire water reservoir 20 within a range of from 10-15 seconds, most preferably in ten seconds. The input of pump 30 is preferably connected to port 31, which is in turn connected to the water intake tube 23 for inducting water into the spout 44 at the distal-extended end below pool surface level. The output of pump 30 is preferably connected via port 32 through the partition 17, and from there by a clear discharge tube 24 into spout 44, which likewise discharges water below the floating waterline of floatation vessel 10.

The solar panel 60 is calibrated to charge the battery bank 50 sufficiently each day to run pump 30 and heating elements 73. To this end the solar panel 60 may be a 100-watt solar panel capable of producing between 300 and 600 watt-hours (Wh) of solar energy per day. The heating elements 73 are mounted on the outside of hub 15 and extend radially therefrom. In a preferred embodiment, three immersion heating elements 73 extend radially at 120 degree increments and substantially traverse the water reservoir 20. The immersion heating elements 73 are electrically connected within hub 15 to a switch controlled by microcontroller module 70. Heating elements 73 are collectively capable of drawing 300 watts and the pump 30 another 50 W and so a 350 W hr lithium battery bank 50 is recommended.

FIG. 6 is a block diagram of the pump assembly 30, temperature sensor 40, temperature sensor 42, fill level sensor 43, battery bank 50, solar cell 60 and microcontroller module 70. The microcontroller module 70 includes a processor 72, on board non-transitory memory 74, and an on-board wireless transceiver 76 for remote communication. An external ON/OFF button initiates operation. The battery bank 50 provides power to the pump 30 through a first fuse block 71, to heating elements 73 through a second fuse block 71, and to microcontroller module 70 via a third fuse block 71. Processor 72 is in communication with temperature sensors 40, 42. As indicated above the temperature sensor 40 is imbedded inside the water reservoir 20 at or near the midpoint to provide a temperature measurement of the water inside the water reservoir 20 to processor 72. In contrast, temperature sensor 42 is preferably embedded in the bottom wall of flotation vessel 10. This way, processor 72 can also monitor the temperature of the pool water.

Fill level sensor 43 is embedded in the wall of hub 15 and protects heating elements 73 by ensuring that they are fully immersed before activation. Microcontroller module 70 may be any suitable low-power computer processor platform with on-board memory 74 and wireless communication capability by, for example, LA N and/or Bluetooth® connectivity via transceiver 76. A software application is stored in memory 74 for execution by processor 72.

FIG. 7 is a schematic diagram of an exemplary solar charging chamber for maintaining battery bank 50 via solar panel 60, which is based on a Texas Instrument™ MPPT BQ 25172 integrated 800-mA linear solar charge controller with solar input.

FIG. 8 is a schematic diagram of an exemplary microcontroller module 70 which is based on an ST™ STM32WB5MMG wireless microcontroller incorporating an Arm® Cortex®-M 4 processor core 72 running at 64 MHz (application processor) and an Arm Cortex-M0+ wireless core 76 (wireless front end), with onboard 1 M byte Flash memory 74 and capable of wireless Bluetooth LE 5.4 and 802.15.4 protocols.

The internal temperature sensor 40 and external temperature sensor 42 may be any suitable temperature sensors capable of accurately sensing a range of from 55° C.˜130° C., such as Texas Instruments™ LM19CIZ/LFT4. Fill level sensor 43 may be any suitable float switch or capacitive water level sensor.

FIG. 9 is a flow diagram of the resident software application stored in memory 74.

At step 110 the solar pool heater 2 is powered up using on/off button 53 and the software instantiates. The software requires several programmed parameter settings all of which initiate to default settings but may be user-customized by wireless transmission from a remote application running on a user's smartphone or other remote device.

Parameter
Description
Default

Low Volt Cut-Off
Min. Battery Charge
  9 v

Pump-time Duration
A Pump Cycle
 10 sec

Dwell Time
A delay
   1 min

Max Temp
Desired Pool Temp
115 F.

Count Limit

At step 115 the processor 72 waits a multiple of the Dwell Time (approx. 11 mins) to allow the user to place the solar pool heater 2 in their pool.

At step 120 the processor 72 measures and compares the battery bank 50 voltage to the Low Volt Cut-Off to ensure that the battery bank 50 has an operational charge. If not, at step 125 a battery error L E D flashes. If the battery bank 50 voltage is greater than the Low Volt Cut-Off, then processor 72 activates the pump assembly 30 for a Pump-time Duration sufficient to prime and automatically fill the entire water reservoir 20, e.g., a Pump-time Duration equals 10 seconds.

At step 130, the processor 72 then waits a predetermined delay period, the Dwell Time (e.g., one minute) for the water in water reservoir 20 to warm fully. The initial delay period is calibrated to ensure that the water in water reservoir 20 reaches its apex temperature, typically resulting in a temperature differential of twenty degrees between the pool water temperature versus the water temperature in the water reservoir 20. U se of an apex temperature differential maximizes the heating advantage of the water reservoir 20 and minimizes the amount of time needed to raise the pool water temperature.

At step 135 the processor 72 measures the apex temperature of the water in water reservoir 20 Ta at sensor 40 and stores the measured apex Ta. Processor 72 then compares the temperature of the water in water reservoir 20 Ta at sensor 40 to the pool water temperature Tp, and so long as Ta>Tp proceeds to step 140.

At step 140 the processor 72 again measures and compares the battery bank 50 voltage to the Low Volt Cut-Off to ensure that the battery bank 50 has an operational charge. If not, flow returns to step 115 to await a full charge. If so, processor 72 activates the pump assembly 30 for a single Pump-time Duration sufficient to refresh the water in water reservoir 20, e.g., one times a Pump-time Duration equals 10 seconds.

At step 141 processor 72 polls the water fill sensor 43 to ensure that the heating elements 73 are fully submerged in water.

If the water fill sensor 43 is fully submerged in water, then at step 143 processor 72 then activates the heating elements 73 to heat water inside active heating chamber 14.

Flow proceeds to step 145 and processor 72 then waits a predetermined delay period, e.g., a single Dwell Time (1 minute) for the new water inducted into water reservoir 20 to warm fully by active heating inside water reservoir 20.

Next, at step 150, the processor 72 measures the apex temperature of the water in water reservoir 20 Ta at sensor 40 and stores the measured apex Ta, and the pool water temperature Tp at sensor 42. Processor 72 the compares the temperature of the water in water reservoir 20 Ta at sensor 40 to the pool water temperature Tp, and if Ta>Tp A N D the pool water temperature Tp is less than the desired pool temperature M ax Temp (115F), flow proceeds to step 175.

At step 175 processor 72 activates the pump assembly 30 for a Pump-time Duration sufficient to refresh the water in water reservoir 20, e.g., one times a Pump-time Duration equals 10 seconds.

At step 180 processor 72 resets a cycle count and returns to step 145.

If at step 150 processor 72 compares the temperature of the water in water reservoir 20 Ta at sensor 40 to the pool water temperature Tp, and either Ta<Tp OR the pool water temperature Tp equals or exceeds the desired pool temperature M ax Temp (115F), flow proceeds to step 155.

At step 155 processor 72 increments the cycle count.

At step 160 processor 72 compares the current cycle count to the Count Limit (e.g., 5 sec). If the current cycle count is less than or equal to the Count Limit flow proceeds to step 145.

If the current cycle count exceeds the Count Limit flow returns to step 130 above. The recirculation steps 145, 150, 175 and 180 repeat as needed, flushing and inducting new water, until the water temperature of the entire pool reaches the desired preset maximum temperature M ax Temp. Use of the foregoing method and apparatus makes it possible to solar-heat an entire pool in approximately four hours. The foregoing disclosure of embodiments of the present invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. M any variations and modifications of the embodiments described herein will be obvious to one of ordinary skill in the art in light of the above disclosure. The scope of the invention is to be defined only by the claims, and by their equivalents.