Swimming pool high velocity heating system

Information

  • Patent Grant
  • 6354573
  • Patent Number
    6,354,573
  • Date Filed
    Monday, September 25, 2000
    24 years ago
  • Date Issued
    Tuesday, March 12, 2002
    22 years ago
  • Inventors
  • Examiners
    • Bushey; C. Scott
    Agents
    • Chandler; Charles W.
Abstract
A jet reactor pump as used to circulate heated water into a swimming pool at near sonic velocity to heat the swimming pool water.
Description




BACKGROUND AND SUMMARY OF THE INVENTION




Swimming pools are conventionally heated by introducing hot water (110° to 120° F.) into the pool at a velocity not exceeding 12 ft/sec to avoid large pressure losses. The heating system (very much like a water heater) heats a copper coil inside which the water travels, wasting 80 to 90% of the heat. Enormous losses occur when trying to heat a standard swimming pool of 22 ft.×15 ft×5 ft with 12,000 gal of water. During the heating process, heat is lost by evaporation from the pool surface to the environment at a rate proportional to the difference in temperature between the pool water and the atmosphere. The slower the water is heated, the greater the heat loss.




Heat transfer velocity is a function of









E



t


=

f


(


Δ






V
2


,
φ
,

Δ





T


)












ΔV


2


=Relative Velocity of the two elements




φ=Flow rate of Heating Media




ΔT=Difference in temperature of the two elements




If superheated gas is introduced into the water at a very high velocity using a jet reactor pump, maximum heat transfer per unit time is possible since:




a) The gas can be introduced at a near sonic velocity (several orders of magnitude over 12 ft/sec)




b) Gas (air) can be heated to any temperature without the concern of vapor locking the system (for fabrication simplicity and safety, I recommend approximately 360° F. to 400° F.).




c) The gas/liquid flow efficiency of a jet reactor pump is well above 50% (volume to volume) which is several times a liquid/liquid pump. A liquid/liquid pump could be used, except that it has a maximum temperature limitation that gas/liquid does not.




d) A 4″ diameter pipe jet reactor pump could circulate all the water in a 12,000-gallon pool in two hours or less vs. 12 to 24 hours for present hot water systems.




e) The losses of heating the water pipe (convection—conduction), to heat the water (convection) and to inject in the pool water (conduction) is eliminated by simply heating the air inserted in the jet reactor that pumps the water as it is being heated.




f) As the water heats up, ΔT diminishes, reducing the heat transfer velocity (in the present systems)




T


water


≈120


20


T


start pool


≈50° F. T


finish pool


=70° F.




ΔT


start


=120−50=70° F.




ΔT


finish


=120−70=50° F.




with gas @ 360° F.




ΔT


start


=360−50=310° F.




ΔT


finish


=360−70=290° F.




This shows almost five times better temperature differential transfer rate at the start of heating, and almost six times better differential at the end of the cycle.




Preferably a compressor is used that is capable of delivering 50 to 75 ft


3


/min. of air @ 50 to 60 psig of pressure (this pressure assures gas sonic velocity in the jet reactor nozzles). Before inserting the air in the jet pump, a heater increases the air temperature to 360° F. to 400° F. The higher the gas temperature, the higher the thermodynamic efficiency of the heating cycle. The gas volume expansion at constant pressure will be:








V
2


V
1


=




T
2


T
1




T
2






and






T
1


=

Absolute





temperature








50







ft
3

/
min

×
860

520




83






ft
3


min











This represents a water flow of approximately 42 ft


3


/


min


of water from the jet reactor pump or over 300


gal


/


min


which would allow the recirculation of a 12,000 gal pool in less than 40 minutes, unheard of in any water heater/water pump system.











DESCRIPTION OF THE DRAWINGS




The description refers to the accompanying drawings in which:





FIG. 1

is a schematic diagram, including a temperature feedback control system for reducing the heater operating temperature as the water in the pool reaches the desired temperature. The system will then maintain the desired temperature, only making up for the convection losses to the atmosphere.





FIG. 2

is an enlarged elevational view of an illustrative pump; and





FIG. 3

is a sectional view of the preferred pump.











DESCRIPTION OF THE PREFERRED EMBODIMENT




Referring to the drawings, a compressor


10


compresses air received from a suitable source through a conduit


12


at 50 ft


3


/min at 50 psig. The compressed air then passes through a conduit


14


to a heater


16


at a rate of 80 c.f.m., which may be either electric or gas. The heater raises the temperature of the compressed gas to about 400° F. The heated gas passes through a conduit means


18


to a gas relief valve


20


and then to the intake of a jet reactor pump


22


. Pump


22


is disposed, for illustrative purposes, in a swimming pool


24


, which contains a body of water


26


having a water level


28


. Preferably, pump


22


has an inlet opening


30


that is three to six feet below water level


28


, a depth of “B”. The pump has an outlet opening


32


for discharging the mixture of water and air, preferably located a depth “A” about 1-3 feet below the water surface.




The general principles of such a jet reactor pump are described in my U.S. Pat. No. 6,039,917, issued Mar. 21, 2000 for “Jet Column Reactor Pump with Coaxial and/or Lateral Intake Opening”.





FIGS. 2 and 3

illustrate a pump useful for pumping and simultaneously introducing air into the body of water


26


. Pump


22


has a cylindrical inlet conduit


34


, a thin annular jet pump cover


36


, and an annular pump body


38


.




Cover


36


is mounted between the upper end of conduit


34


and pump body


38


, as viewed in FIG.


3


. Pump body


38


is welded to cover


36


, and has an inlet opening


40


for receiving an air-receiving conduit


46


. Inlet opening


40


is connected to an annular passage


48


that extends around the path of motion of the water generally shown in the direction of arrow


50


. Conduit


46


delivers air from compressor


10


. The pump materials may be of any suitable material that is compatible with the swimming pool water.




The jet pump body has three annularly spaced jet openings


52


, connected to passage


48


to the downstream face of the pump body. Openings


52


are disposed at an angle “C” of about 7.5° with respect to water motion


50


, to deliver the air in a conical path at sonic or near sonic velocity (whichever is best suited to the application) into the water flow. This arrangement transfers the air momentum to the water thereby increasing the pump efficiency. The compressed air is introduced into the water and expands to create a flow from inlet opening


30


to outlet opening


32


which in turn circulates the water in swimming pool


24


.




Assuming the pool water temperature at the start of the heating cycle is at temperature T


1


of 50° F., and it is desired to increase the temperature of the water to a temperature of T


2


of 70° F. The pump circulates the water in the pool while at the same time heating the pool water with the heated air.




A sensing conduit


53


measures the water temperature and feeds back a signal to water temperature feedback valve


54


that controls the temperature output of the heater temperature controller


56


. The heater temperature controller adjusts the heat output of heater


16


to a rate that accommodates the difference between the actual temperature of the water and the desired temperature.




The pool can be heated very quickly in 1-2 hours vs. 48-64 hours using present heating systems. After the pool is heated, the system is automatically reset for holding the injected air at 140°-160° F. in a sonic velocity transfer process to maintain the pre-selected temperature.




Preferably, no one is permitted to swim in the pool during the accelerated heating, for safety reasons. It is believed that the system using a low gas (air) flow and inexpensive equipment and operation costs will cost about 10%-15% of currently available commercial systems.



Claims
  • 1. A method for heating a body of a liquid from a first lower temperature T1, to a second higher temperature T2, comprising the steps of:compressing a gas; heating the compressed gas to a third temperature T3, higher than a second higher temperature T2; introducing the compressed heated gas into an elongated heating conduit disposed in a body of a liquid having a lower temperature T1 such that the gas expands to induce a flow of the liquid in the heating conduit and raises the temperature of the flowing liquid in the heating conduit to a temperature greater than said second temperature T2, and then delivering the heated flowing liquid from the heating conduit into the body of the liquid to raise the temperature thereof toward temperature T2 at a heat transfer rate that is in accordance with the velocity of the heated liquid flowing from the heating conduit into the body of the liquid.
  • 2. A method as defined in claim 1, including the step of using a jet reactor pump to circulate the liquid in the body of liquid.
  • 3. A method as defined in claim 1, including the step of heating and compressing air.
  • 4. Apparatus for heating and circulating a liquid in a container having an initial temperature T1, comprising:an elongated heating conduit having a liquid inlet opening disposed beneath the surface of a liquid in a container of the liquid, the liquid having a lower temperature T1; the heating conduit having a liquid outlet opening for discharging liquid received in the inlet opening along a path of motion, to a location beneath the surface of the liquid in the container; means for compressing a gas; means for heating the compressed gas to a temperature T3, which is greater than the temperature T1 of the liquid in the container; a plurality of gas-discharge nozzles in the heating conduit disposed around the path of motion of the liquid flowing through the elongated heating conduit; a gas delivery conduit connected to the heating conduit for delivering heated, compressed gas to the gas-discharge nozzles such that the heated gas induces a flow of liquid from the inlet opening to the outlet opening of the heating conduit and heats the induced liquid flowing through the heating conduit to a temperature greater than temperature T1; and the outlet opening of the elongated conduit being disposed to introduce the heated liquid flowing from the conduit into the body of liquid to heat the body of liquid to temperature T2 at a heat transfer rate that is in accordance with the velocity of the heated liquid flowing from the outlet opening of the heating conduit into the body of the liquid.
  • 5. Apparatus as defined in claim 4, including a temperature feedback valve means for measuring the internal water temperature in the pool of water, and means connecting the feedback valve means to the heating means for controlling the heat input into the compressed air that accommodates the difference between the internal water temperature T1 and a desired water temperature T2.
  • 6. Apparatus as defined in claim 5, in which the feedback valve is operative to signal the heating means to heat the water at an accelerated rate when the difference between T1 and T2 is greater than a desired ΔT, and at a standby rate when the temperature difference is relatively stable.
US Referenced Citations (12)
Number Name Date Kind
520342 Sutro May 1894 A
1982258 Martin Nov 1934 A
2055211 Yoder Sep 1936 A
2135043 Seman Nov 1938 A
2297768 Hutchings Oct 1942 A
3095463 Chang et al. Jun 1963 A
3756220 Tehrani et al. Sep 1973 A
4189791 Dundas Feb 1980 A
5605653 Devos Feb 1997 A
5863314 Morando Jan 1999 A
6039917 Morando Mar 2000 A
6103123 Gantzer Aug 2000 A
Foreign Referenced Citations (1)
Number Date Country
201014 Mar 1907 DE