Abstract:
An apparatus and method are disclosed for cooling one or more exercising or resting individuals by applying a water mist and dry air. The apparatus can be free standing, fixed to the walls or ceiling, or attached to an object on which an individual is resting or exercising. The mist and dry air can be applied together or separately, simultaneously or alternately, with varying timing and intensity. In some embodiments, the mist and dry air are manually controlled or operate according to the passage of time. In other embodiments the need for cooling is determined by one or more physiological parameters measured by sensors directed toward or attached to an individual, or embedded in an object on which an individual is resting or exercising. Still other embodiments estimate the heating of the individual by measuring the amount of work performed or the rate of energy expenditure.

Description:
FIELD OF THE INVENTION 
     The invention generally relates to devices and methods for cooling individuals, and more specifically to evaporative cooling of individuals. 
     BACKGROUND OF THE INVENTION 
     There are many circumstances wherein individuals can become overheated. Vigorous exercise is a clear example, as well as leisure activities under conditions of high temperatures and/or intense sunlight. Active and effective cooling of individuals under these circumstances can protect their health and significantly increase their comfort and enjoyment. 
     Evaporative cooling is well known as a highly effective means for cooling individuals. Indeed, it is the mechanism by which the body cools itself through perspiration. The discomfort and potential dehydration of cooling by perspiration can be avoided through the application of a mist of water to an individual, which cools the body in essentially the same manner as perspiration, and can be even more effective than perspiration since the mist impacts the skin at a temperature significantly below body temperature, and hence absorbs more heat than an equivalent quantity of perspiration. 
     Means for generating and applying a water mist to one or more individuals are well known. However, misting does not always provide sufficient cooling efficiency, due to limited evaporation rates. Also, misting can lead to wetness if the evaporation rate is not sufficient. 
     SUMMARY OF THE INVENTION 
     An apparatus and method are disclosed for cooling at least one individual with water droplets and dry air. The apparatus combines a device for applying water droplets to one or more individuals with a means for applying dry air so as to increase the rate of evaporation, thereby increasing the cooling efficiency, and reducing the tendency for water to accumulate. 
     In preferred embodiments, the water droplets are in the form of a mist, a spray, or a shower. In some preferred embodiments, the apparatus is attached to an object on which an individual is resting or exercising. 
     In further preferred embodiments, the apparatus is able to direct a flow of dry air onto an individual, and in various preferred embodiments the apparatus is able to control the direction and/or speed of the dry air, inject water droplets into the flow of dry air, continue to apply dry air while intermittently applying droplets, and/or alternate between applying dry air and droplets. 
     In preferred embodiments, the apparatus is free standing, is built into a wall or ceiling, or is part of the climate control system for an entire room. Depending on the preferred embodiment, the device for applying water droplets controls one or more of the duration of emitting of water droplets, frequency of emitting of water droplets, numerical density of emitted water droplets, size of emitted water droplets, temperature of emitted water droplets, direction of travel of emitted water droplets, speed of travel of emitted water droplets, and rate of divergence of emitted water droplets. 
     In some preferred embodiments, the apparatus is manually controlled, while in other preferred embodiments the apparatus is automatically controlled. In some of the latter preferred embodiments, the apparatus is controlled according to the passing of time and/or according to one or more measured physiological parameters such as the skin temperature, core body temperature, heart rate, and rate of perspiration. Physiological parameters can be measured by sensors attached to or directed toward an individual or sensors embedded in an object or device on which an individual is resting or exercising. In other preferred embodiments the apparatus is automatically controlled at least partly according to the amount of activity and/or the amount of energy exerted on an exercise machine. 
     Some preferred embodiments also include an airborne droplet detection device and limit the application of mist so as to avoid an undesirable amount of airborne droplets. 
     The method of the invention includes applying water droplets to an individual in coordination with providing dry air at least near the individual, so as to promote the evaporation of the water droplets. Preferred embodiments of the method include providing an apparatus as described above and applying dry air as a directed flow onto the individual. 
     Another aspect of the method includes applying water droplets to an individual in an enclosed environment containing dry air, so as to take advantage of dry air properties that enhance evaporation of water droplets and thereby increase evaporative cooling efficiency. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a block diagram of a general embodiment of the invention; 
         FIG. 1B  is a functional diagram of a preferred embodiment wherein mist and dry air are applied simultaneously at a fixed ratio; 
         FIG. 1C  is a functional diagram of a preferred embodiment wherein mist and dry are applied simultaneously with a variable ratio; 
         FIG. 1D  is a functional diagram of a preferred embodiment wherein mist is applied separately, followed by dry air; 
         FIG. 1E  is a functional diagram of a preferred embodiment wherein dry air is applied separately, followed by mist; 
         FIG. 1F  is a functional diagram of a preferred embodiment wherein multiple bursts of mist and dry air are applied alternately; 
         FIG. 1G  is a functional diagram of a preferred embodiment wherein multiple bursts of dry air and mist are applied alternately; 
         FIG. 2A  is a perspective drawing of a reclining individual being cooled by a free standing, self-contained embodiment of the invention that uses a skin temperature sensor attached to the individual to detect the need for cooling, and applies dry air mixed with mist; 
         FIG. 2B  is a perspective drawing of an individual sitting on a lounge chair being cooled by an embodiment of the invention that includes an air drying apparatus and is externally supplied with water, uses a core body temperature sensor attached to the chair to determine the need for cooling, and applies separate streams of dry air and mist; 
         FIG. 2C  is similar to  FIG. 2B , except that the dry air is externally supplied, and the device is manually controlled; 
         FIG. 3A  is a perspective drawing of an embodiment wherein a plurality of individuals exercising in a room is cooled by mist from the ceiling and dry air from an air duct on the wall; 
         FIG. 3B  is a perspective drawing of an embodiment wherein a plurality of individuals exercising in a room is cooled by mist from the ceiling and a flow of dry air near the floor, while the need for cooling is monitored by skin temperature sensors attached to the foreheads of the individuals; 
         FIG. 4A  is a perspective drawing of an individual exercising on a stationary exercise device being cooled by a combined flow of mist and dry air from above, while the individual&#39;s heartbeat as measured by a sensor in a hand grip of the device is used to determine the need for cooling; 
         FIG. 4B  is a perspective drawing of an individual on a stationary exercise device being cooled by a flow of water droplets from above and a flow of dry air from below; 
         FIG. 4C  is a perspective drawing of an individual on a stationary exercise device being cooled by a flow of water droplets from above and a flow of dry air past the individual from the room into a vent below the exercise device; 
         FIG. 4D  is a perspective drawing of an individual on a stationary exercise device being cooled by a flow of water droplets from behind emitted by a water droplet emission device attached to the exercise device; 
         FIG. 5  is a perspective drawing of a plurality of individuals on exercise devices, each being cooled from above by a separate source of water droplets combined with dry air; 
         FIG. 6A  is a logic diagram that depicts cooling with mist followed by dry air where the need for cooling is determined by a sensor that measures a physiological parameter: 
         FIG. 6B  is a logic diagram that depicts cooling with mist followed by dry air where the need for cooling is estimated according to the amount of work done on an exercise machine: 
         FIG. 7A  is a graphical presentation of mist control strategies for exercising and resting individuals in preferred embodiments wherein the droplets are applied intermittently and wherein sensors are used to measure the skin temperatures of the individuals; 
         FIG. 7B  is a graphical presentation of a mist control strategy for an exercising individual in a preferred embodiment wherein the water droplets are applied intermittently and a sensor is used to measure the deviation of the core body temperature of the individual away from a baseline temperature; 
         FIG. 7C  is a graphical presentation of a mist control strategy for a resting individual in a preferred embodiment wherein the intensity of water droplets is varied until the cooling effect of the water droplets is sufficient to maintain a desired skin temperature; 
         FIG. 7D  is a graphical presentation of a mist control strategy wherein the density of the mist is varied according to a measured pulse rate of an exercising individual; 
         FIG. 7E  is a graphical presentation of a mist control strategy wherein the density of the mist is varied according to the ratio of the measured pulse rate of an exercising individual to the age related maximum pulse rate for the individual; 
         FIG. 8  is a front drawing of a control panel for a preferred embodiment wherein the user manually adjusts the desired level of misting intensity and dry air intensity; and 
         FIG. 9  is a front drawing of a control panel for a preferred embodiment wherein the apparatus is automatically controlled according to the measured skin temperature and percent of age-related maximum pulse rate of an individual, and wherein the apparatus controls the air flow and humidity of the air near the individual in addition to the application of mist. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     With reference to  FIG. 1A , the basic invention is a cooling apparatus  100  that includes a water droplet application device  102 , and a dry air application device  104 . If an individual is too warm  106 , cooling is requested, either due to direct adjustment of a manual control or due to an automatically generated signal according to the passage of time and/or according to one or more measured physiological parameters. The apparatus of the invention  100  responds by applying mist  102  and dry air  104  to the individual. 
       FIG. 1B  through  FIG. 1F  illustrate different strategies for applying mist and dry air for cooling an individual. In  FIG. 1B , mist and dry air are applied simultaneously with fixed relative amounts  108  whenever the individual is too warm, and the application of mist and dry air  108  is halted when the individual is no longer too warm. In  FIG. 1C , the ratio of mist to dry air is increased  110  if the individual is too warm, and decreased  112  if the individual is too cold. In  FIG. 1D , if the individual is too warm mist is applied separately  114 , and then dry air is applied  116 , while in  FIG. 1E  dry air is applied first  116 , followed by mist  115 .  FIG. 1F  is the same as  FIG. 1D , and  FIG. 1G  is the same as  FIG. 1E , except that the alternate application of mist  114  and dry air  116  is repeated multiple times. 
       FIG. 2A  is a perspective view of a preferred embodiment wherein cooling mist and dry air  200  are applied simultaneously and in a fixed ratio to an individual  202  lying down in a restful position. The mist and dry air application device  204  is supported by a free-standing base that includes containers of water and compressed dry air  206 . The need for cooling is determined at least partly according to the skin temperature of the individual  202  as measured by a sensor  208 , which in  FIG. 2A  is a thermocouple attached to the forehead of the individual  202 . The sensor  208  communicates with a mist and dry air controller  210  by transmitting wireless signals to the controller  210 . 
     In order to avoid false readings, whenever possible skin temperatures and core body temperatures are measured at locations that are not directly cooled by mist and dry air. For example, the head band in  FIG. 2A  is placed at a location where the sensor is not directly cooled by the mist. In addition, the headband is made from a water repellent material containing thermal insulation so as to further isolate the sensor from the mist, and so as to prevent any evaporative cooling of the skin region where the sensor is attached, including evaporative cooling by perspiration. In other embodiments, a tympanic membrane temperature sensor can be used, since the tympanic membrane will not be significantly cooled by the mist. In still other embodiments, the skin temperature of the individual  202  is measured by a sensor, such as an infra-red sensor, that is directed toward but not directly attached to the individual  202 . 
       FIG. 2B  is a perspective view of a preferred embodiment that is similar to the embodiment of  FIG. 2A , except that the individual  202  is resting on a reclining chair  214  and the mist  216  and dry air  218  are applied by separate devices  220 ,  222  that are separately controlled. Water for the mist  224  is supplied by an external source of water (not shown), and dry air is provided by an air drying apparatus  226  supplied by a source of electrical power (not shown). The need for cooling is determined at least partly according to the core body temperature of the individual  202  as derived from measurements made by a sensor  228  embedded in the back of the chair such that it rests against the neck of the individual  202 . 
       FIG. 2C  is a perspective view of an embodiment similar to the embodiment of  FIG. 2B , except that the dry air is supplied by an external dry air source  230 , and the cooling is controlled by the individual  202  through a manual control unit  232  attached at a convenient location to an arm of the recliner  214 . 
       FIG. 3A  is a perspective view of an exercise room  300  in which a group of individuals  302  is exercising on a mat  304  while being cooled by mist  306  emitted by water droplet application devices  308  mounted in the ceiling of the room  300  and dry air  310  emitted from a duct in the wall of the room  300 . The mist  308  and the dry air  310  are separately controlled by a manually settable controller  312  mounted on the wall. 
       FIG. 3B  is a perspective view of an embodiment similar to the embodiment of  FIG. 3A , except that the controller  312  operates at least partly according to core body temperature measurements from sensors  314 , such as infrared temporal artery sensors, attached to the foreheads of the individuals  302  and transmitted wirelessly to an antenna  316  on the control unit. Also, in this embodiment the source of dry air  310  directs a flow of dry air onto the mat  304 , so as to prevent the mat  304  from becoming slippery due to water accumulation. 
       FIG. 4A  is a perspective view of an individual  400  exercising on an exercise device  402  while being cooled by a combined flow of water droplets  404  and dry air  406 . A water droplet emission device  408  injects water droplets into a stream of dry air from a dry air source  410 . The control unit  412  operates according to the pulse rate of the individual  400  as measured by a sensor embedded in a handle of the exercise device  402  and transmitted to the control unit  412  by a wire  414 . 
       FIG. 4B  and  FIG. 4C  are perspective views of preferred embodiments similar to the embodiment of  FIG. 4A , except that the water droplets  404  are not injected into the flow of dry air  406 . Instead, in  FIG. 4B  the droplets  404  are applied from above the individual  400  while the flow of dry air  406  is applied from below, while in  FIG. 4C  the droplets  404  are applied from above the individual  400  while dry air  406  flows past the individual and into a vent  410  in the floor below the individual. In the embodiment of  FIG. 4C , the ambient air in the room  406  is dry, either due to the local climate or due to drying of the air in the room by de-humidification or air conditioning means. Drawing of the air into a vent  410  in the floor therefore ensures that the individual  400  is always surrounded by and in contact with dry air  406 . 
       FIG. 4D  is a perspective view of a preferred embodiment in which a frame  416  is used to attach the apparatus of the invention to an exercise device  402 . In this embodiment, a mixture of water droplets  404  and dry air  406  is applied to the individual  400  from behind by a manually controlled device  418  supplied by an external source of water  224  and an air drying apparatus  226  supplied with electrical energy from an external source (not shown). 
       FIG. 5  is a perspective view of a preferred embodiment in which a plurality of individuals  500  using a plurality of exercise devices  502  are cooled by a combined flow of mist  504  and dry air  506  emitted by water droplet and dry air application devices  508  positioned above the exercise devices  502 . The water droplet and dry air application devices  508  are controlled by a single control unit  510 . The need for cooling is determined at least partly according to skin temperature measurements transmitted wirelessly from sensors  512  attached to the individuals  500  and received by an antenna  514  attached to the control unit  510 . 
     In preferred embodiments, the control unit  510  can operate according to average skin temperature measurements obtained from the plurality of individuals  500 , or they can separately control the misting and the application of dry air to each of the individuals  500 . In addition, airborne water droplet sensors  516  measure the density of water droplets in the air near the ground, and transmit this information wirelessly to the antenna  514  on the controller  510 . This information is used to limit the application of water droplets and increase the application of dry air, thereby preventing an excess density of water droplets in the air near the floor. 
       FIG. 6A  and  FIG. 6B  are logic diagrams that depict strategies for determining the need for cooling an individual. In  FIG. 6A , a comparison  600  is made between a sensor reading  602  and an allowable maximum sensor reading  604 , where in various embodiments the sensor reading  602  is a measurement of a physiological parameter such as skin temperature, core body temperature, or pulse rate. If the allowable maximum sensor reading is exceeded  606 , mist is applied  608 , followed by dry air  610 . In similar embodiments, other cooling strategies, such as those shown in  FIG. 1B through 1G , are used. For example, mist and dry air are applied simultaneously, dry air is applied followed by mist, or mist and dry air are applied simultaneously and continuously but the total intensity and/or the relative amounts of mist and dry air are varied. 
     In  FIG. 6B , a sensor  610  in an exercise machine is used to determine the total work done  612  by an individual, and from this measurement an estimate is made  614  of the heating of the individual. The estimated heating  614  is compared  600  to an allowable maximum value  604 , and if the estimated heating  614  exceeds  606  the allowable maximum value  604  mist is applied  608 , followed by dry air  610 . As with  FIG. 6A , in similar embodiments other cooling strategies, such as those shown in  FIG. 1B through 1G , are used. For example, mist and dry air are applied simultaneously, dry air is applied followed by mist, or mist and dry air are applied simultaneously and continuously but the total intensity and/or the relative amounts of mist and dry air are varied. 
       FIG. 7A  is a graphical presentation of mist and dry air control strategies for exercising  700  and resting  702  individuals in preferred embodiments where the mist and dry air are applied alternately  704 ,  706  with a variable mist/dry air ratio  708 . In each case, the mist/dry air ratio  708  is adjusted according to the measured skin temperature  710  of the individual, with the mist/dry air ratio  708  being increased linearly as the measured skin temperature  710  rises. 
       FIG. 7B  is a graphical presentation of a mist control strategy for an exercising  700  individual in a preferred embodiment similar to  FIG. 7A , except that the mist/dry air ratio  708  is increased linearly as the measured core body temperature  712  rises above a baseline temperature. 
       FIG. 7C  is a graphical presentation of a mist and dry air control strategy for a resting individual  702  in a preferred embodiment wherein the density of water droplets in dry air  714  is varied  716 ,  718  until a point is reached  720  where no further changes of the density  714  are needed to maintain a desired skin temperature  722 . 
       FIG. 7D  is a graphical presentation of a mist control strategy for an exercising individual  700  wherein the density  724  of the water droplets in dry air is increased linearly as the measured pulse rate  726  of the individual rises. 
       FIG. 7E  is similar to  FIG. 7D , except that the density  724  of the water droplets is linearly increased as the measured heart rate approaches the age related maximum heart rate  728  for the individual. 
       FIG. 8  is a front drawing of a simple control panel for a preferred embodiment such as the embodiment of  FIG. 2C  wherein the user manually adjusts the desired level of misting intensity  800  and the dry air flow rate  802 . In different embodiments the misting intensity  800  represents the on/off ratio of an intermittent flow, a water droplet density of a continuous flow, an average rate of droplet application, or any other factor or combination of factors that determine the overall rate at which droplets are applied to the individual. In this embodiment, the user selects from between four levels of intensity, labeled “High,” “Medium,” “Low,” and “Off.” 
       FIG. 9  is a front drawing of a control panel for a preferred embodiment wherein the apparatus is automatically controlled according to the measured skin temperature and measured percent of age-related maximum pulse rate of an individual. A maximum skin temperature  900  is entered using pushbuttons  902 ,  904 , and is compared to a measured skin temperature  906 . Also, the individual&#39;s age  908  is entered using pushbuttons  910 ,  912 , and is used to compute the age related maximum pulse rate of the individual. The individuals actual pulse rate is measured by a sensor, and is displayed  914  as a percent of the individual&#39;s age-related maximum pulse rate. If the actual skin temperature  906  rises above the user specified maximum preferred skin temperature  900 , and/or if the percentage of age-related maximum heart rate  914  rises too high, then the controller applies a combination of mist  916 , and dry air  918 , according to a strategy such as one of the strategies shown in  FIG. 1B  through  FIG. 1G . The controller also controls the rate of dry air flow past the individual by use of a controllable fan  920 . A power indicating light  922  is also provided to indicate that the unit is switched on. 
     Other modifications and implementations will occur to those skilled in the art without departing from the spirit and the scope of the invention as claimed. Accordingly, the above description is not intended to limit the invention except as indicated in the following claims.