Abstract:
A compact tank-less self-contained modular hot water supply system is provided for utilizing steam by-products from boiler systems for on-demand supply of temperature-controlled hot water in high volumes suitable for commercial applications. The modular system includes a brazed-plate type heat exchanger with a steam side providing a heating source, and a separate water side for production and delivery of hot water. Precise temperature control is provided by a module that adjusts the temperature of the hot water supply in communication with a module that regulates the flow of steam into the heat exchanger. The modular hot water supply system is contained within a housing which is mountable on a vertical or a horizontal surface.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims the benefit of U.S. Provisional Application No. 60/581,701 filed Jun. 23, 2004 entitled “Compact Steam-Fed Heat Exchange System.” 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates to the field of heat exchange systems, and more particularly, to compact/modular steam-fed heat exchange systems for on-demand high-volume output of controlled-temperature hot water.  
       BACKGROUND  
       [0003]     Commercial dry-cleaning operations have a high demand for hot water. Even a lower-capacity washing machine used in commercial dry-cleaning operations has four washing cycles per load with each cycle requiring at least two gallons of hot water (i.e., at a temperature approximately 65° C.). It is common for each machine to process two loads per hour thereby requiring a supply of sixteen gallons of hot water per hour. However, cosiderable heat is lost during the washing process and therefore, the total hourly hot water requirement for said low-capacity washing machine is double the, volume required for the physical washing process, i.e., a total of 32 gallons per hour (GPH).  
         [0004]     A small commercial dry-cleaning operation may have three of these types of low-capacity washing machines thereby requiring a hot water supply of 96 GPH. This translates into an energy requirement of approximately 150,000 British Thermal Units per hour (BTUH). Medium-sized dry-cleaning operations may have five or more such washing machines thereby requiring 160 GPH with a concomitant energy requirement of 250,000 BTUH. These hot water requirements are typically supplied by gas-fired insulated hot water heaters in the 100-gal range which sometimes feed larger storage tanks in the 500-gal. range. Larger plants for commercial laundry or dry-cleaning operations often require 800 to 1,000 GPH. Hot water requirements of this scale are supplied by boiler-generated steam. Furthermore, most commercial laundries and dry-cleaning facilities also require boiler-generated steam for operating presses and other equipment.  
       SUMMARY OF THE INVENTION  
       [0005]     According to one exemplary aspect of the present invention, there is provided a compact tank-less modular heat exchange system for utilizing energy derived from boiler-generated steam for production of an on-demand supply of temperature-controlled hot water. The steam side of the heat exchange system comprises a steam inlet, a steam trap, a steam valve feeding into the inlet side of a plate-type heat exchange unit. The steam side of the heat exchange unit exits into a steam trap feeding a condensate outlet line. The water side (i.e., the fluid side) of the plate-type heat exchange unit is connected to a cold water supply line which is passed through water strainer and check valve modules. The outlet of the fluid side of the heat exchange unit is connected to a dual pressure/temperature valve. The temperature of hot water exiting the fluid side of the heat exchange unit is modulated by a thermocouple connecting the outlet of the fluid side of the heat exchange unit with the steam valve.  
         [0006]     According to another exemplary aspect of the present invention, there is provided a heat exchange system for utilizing the energy derived from steam for production of an on-demand supply of temperature controlled hot water. The steam side of the heat exchange system comprises a steam inlet, a steam trap, a steam valve feeding into the inlet side of a plate-type heat exchange unit. The steam side of the heat exchange unit exits into a steam trap and a condensate outlet line. The water side (i.e., the fluid side) of the plate-type heat exchange unit is connected to a cold water supply line which is passed through water strainer and check valve modules. The outlet of the fluid side of the heat exchange unit is connected to a dual pressure/temperature valve. The temperature of hot water exiting the fluid side of the heat exchange unit is modulated by a thermocouple connecting the outlet of the fluid side of the heat exchange unit with the steam valve. The system is also provided with a dual pressure/temperature relief valve to facilitate the on-demand supply and delivery of temperature-controlled hot water.  
         [0007]     According to another exemplary aspect of the present invention, there is provided a hot water supply system comprising: a first module having a steam path between a steam inlet and a steam outlet and a water path between a water inlet and a water outlet, the water path being in proximity to the steam path; a second module for supplying a flow of steam to the steam inlet of the steam path of the first module; a third module for receiving the flow of steam from the steam outlet of the steam path in the first module; a fourth module for supplying a cold water supply to the water inlet of the water path of the first module; a fifth module for receiving a hot water supply from the water outlet of the water path of the first module; and a sixth module for controlling the temperature of the hot water supply from the fifth module for delivery.  
         [0008]     According to yet another exemplary aspect of the present invention, there is provided a compact tank-less modular heat exchange system for production of an on-demand supply of temperature controlled hot water wherein the system is self-contained within a housing. The housing is mountable on a vertical wall or alternatively, on a horizontal support.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]     The present invention will be described in conjunction with reference to the following drawings in which:  
         [0010]      FIG. 1  is a cross-sectional right side view of one embodiment of the present invention;  
         [0011]      FIG. 2  is a cross-sectional left side view of the embodiment shown in  FIG. 1 ;  
         [0012]      FIG. 3  is a rear view of the embodiment shown in  FIG. 2 ;  
         [0013]      FIG. 4  is a cross-sectional left side view of another embodiment of the present invention; and  
         [0014]      FIG. 5  is a rear view of the embodiment shown in  FIG. 4 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0015]     Embodiments of the present invention provides a compact modular steam-fed heat exchange system for supplying an on-demand high-volume output of controlled-temperature hot water without the requirement for storage tanks to hold heated water; The tank-less heat exchange system uses the waste energy given off by boiler-generated steam used in commercial-scale laundry and dry-cleaning equipment such as driers and presses, to heat cold water to useful high temperatures. Embodiments of the present invention provide a wide range of thermal output capacities using a fraction of the space and volumes required by conventional hot water generating systems.  
         [0016]     One embodiment of the present invention for a modular steam-fed heat exchange system for providing on-demand high-volume output of temperature controlled hot water is illustrated in  FIGS. 1, 2  and  3 . The heat exchange system is comprised of a steam side that provides the energy source for heating water, while the fluid side provides the supply of water to be heated to various temperatures on demand.  
         [0017]     The steam side is illustrated in  FIG. 1  wherein waste steam from a boiler system is introduced through inlet  10  comprising a brass nipple  11 . Steam inlet  10  is fitted with a steam pressure relief valve  12  that is connected to nipple  21  by means of a tee coupling  13 . A modulating steam valve  14  controls the entry of steam into a heat exchange unit  15 . The outlet on the steam side of the heat exchange unit  15  is connected by inline coupling  16  to a steam trap  17 . As heat is transferred from steam during its passage through the steam side of heat exchange unit  15 , the steam condenses into water which is collected in the steam trap  17  and then removed from the system through the condensate line out  22 .  
         [0018]      FIG. 2  illustrates the fluid, i.e. water, side of the heat exchange system. Nipple  31  serves as the cold water inlet  30  connected at one end to a water strainer  32 , which serves to remove physical particles from water entering the system. Water strainer  32  is connected to a check valve  33  by nipple  41 . The water then passes into the heat exchange unit  15  where it is heated by the steam passing through the steam side of the heat exchange unit  15 . The heated water leaves the fluid side of the heat exchange unit through nipple  51 , which is attached at one end to the heat exchange unit  15  by means of a union  34 . The other end of nipple  51  is attached to a tee coupling  35 . One end of tee coupling  35  is attached to nipple  61 , which is fitted with an elbow (e.g., 90°)  36 , which is connected to a nipple  71 .  
         [0019]     The nipple  71  is connected to the inlet side of a dual pressure/temperature gauge/valve  37 . The outlet side of the dual pressure/temperature gauge is fitted with nipple  81  that serves as the hot water outlet  38  for the engineered modular steam-fed heat exchange system of the present invention. If so desired, a cold water supply may be connected to the dual pressure/temperature gauge by means of nipple  91  connected at one end to the water strainer  32  and at the other end to a mixing valve (not shown). A hex-nipple  23  is attached to the third opening of tee coupling  35 .  
         [0020]     One end of a thermocouple  20  is connected to the hex-nipple  23 , while the other end of thermocouple  20  is connected to steam valve  14 . Thermocouple  20  modulates the amount of steam allowed to pass through steam valve  14  into the heat exchange unit thereby precisely controlling the heating of cold water passing into the fluid side of the heat exchange unit  15 , to a selected temperature.  
         [0021]     Another embodiment of the present invention is shown in  FIG. 4  wherein the hot water transfer system exiting the fluid side of the heat exchange unit  15  through nipples  51  and  61 , is provided with a dual pressure/temperature relief valve  43 . Nipple  61  is connected to a tee coupling  42  which at one end is attached to the dual pressure/temperature relief valve  43  and at the other end, is attached to a nipple  121 , which is attached to a tee coupling  45 . Tee coupling  45  is connected to a dual pressure/temperature gauge  37  by means of a bushing  46 . The dual pressure/temperature gauge controls the release of hot water out of the hot water outlet by means of nipple  131 . The dual pressure/temperature pressure relief valve makes it possible to deliver a lower temperature of on-demand hot water under constant pressure by providing an outlet  44  for through nipples  91  and  111 . If so desired, a cold water supply may be connected to the dual pressure/temperature gauge  37  by means of nipple  91  connected at one end to the water strainer  32  and at the other end to a mixing valve (not shown).  
         [0022]     The modular steam-fed heat exchange system according to the various embodiments of the present invention for providing on-demand high-volume output of temperature controlled hot water does not require pre-heating, then storage and maintenance of heated water in insulated tanks. Rather, the various embodiments of the present invention provides a constant on-demand supply of hot water at temperatures that can be controlled by using steam generated by-products from boilers, passing said steam through the steam side of a heat exchange unit, and using the energy derived from the steam to heat a cold water supply passing through the fluid side of the heat exchange unit. The temperature of the hot water produced can be controlled using a thermocouple (for example) cooperating with: (a) a dual pressure/temperature relief valve on the fluid side of a heat exchange unit, and (b) a modulating steam valve on the steam side of the heat exchange unit. Furthermore, embodiments of the present invention do not require the use of electrical controls or connections for its operation.  
         [0023]     The various modular heat exchange systems according to embodiments of the present invention discussed above can be housed within a container having, as illustrated in  FIGS. 3 and 5 , a right side wall  19 , a left side wall  37 , a back wall  39 , along with a top, bottom and front wall (not shown). The heat exchange unit  15  is attached to the right side wall  19  of the container by mounting plate  18 . The container can be mounted on a wall or alternatively if so preferred, on a horizontal support (not shown). This results in a relatively compact practical implementation of a heat exchange system. By way of example, modules required for a 250,000 BTUH supply of on-demand hot water (i.e., to supply 250 GPH) can be housed within a steel container with the dimensions of 40 cm wide×50 cm high×20 cm deep (i.e., 16″×20″×8″). In this particular example, a plate-type heat exchange unit comprised of 8 plates can be used. In a second example, modules required for a 1.25 million BTUH supply of on-demand hot water (i.e., to supply 1,200 GPH) can be housed within a steel container with the dimensions of 50 cm wide×50 cm high×20 cm deep (i.e., 20″×20″×8″). In this particular example, a plate-type heat exchange unit comprised of 40 plates can be used.  
         [0024]     The present invention is amenable for producing hot water for a variety of commercial applications such as but not limited to, the dry-cleaning industry, laundry facilities for hotels and hospitals, restaurants and the hospitality industries.