EP3488169A1 - Ultra narrow channel ultra low refrigerant charge evaporative condenser - Google Patents

Ultra narrow channel ultra low refrigerant charge evaporative condenser

Info

Publication number
EP3488169A1
EP3488169A1 EP17832023.0A EP17832023A EP3488169A1 EP 3488169 A1 EP3488169 A1 EP 3488169A1 EP 17832023 A EP17832023 A EP 17832023A EP 3488169 A1 EP3488169 A1 EP 3488169A1
Authority
EP
European Patent Office
Prior art keywords
water
housing
tube bundle
inches
refrigerant
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP17832023.0A
Other languages
German (de)
French (fr)
Other versions
EP3488169A4 (en
Inventor
Thomas Bugler
Trevor HEGG
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Evapco Inc
Original Assignee
Evapco Inc
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 Evapco Inc filed Critical Evapco Inc
Priority claimed from PCT/US2017/043557 external-priority patent/WO2018018049A1/en
Publication of EP3488169A1 publication Critical patent/EP3488169A1/en
Publication of EP3488169A4 publication Critical patent/EP3488169A4/en
Withdrawn legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B39/00—Evaporators; Condensers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B39/00—Evaporators; Condensers
    • F25B39/04—Condensers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28C—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA COME INTO DIRECT CONTACT WITHOUT CHEMICAL INTERACTION
    • F28C1/00—Direct-contact trickle coolers, e.g. cooling towers
    • F28C1/14—Direct-contact trickle coolers, e.g. cooling towers comprising also a non-direct contact heat exchange
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D1/00—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators
    • F28D1/02—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid
    • F28D1/04—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with tubular conduits
    • F28D1/0408—Multi-circuit heat exchangers, e.g. integrating different heat exchange sections in the same unit or heat exchangers for more than two fluids
    • F28D1/0426—Multi-circuit heat exchangers, e.g. integrating different heat exchange sections in the same unit or heat exchangers for more than two fluids with units having particular arrangement relative to the large body of fluid, e.g. with interleaved units or with adjacent heat exchange units in common air flow or with units extending at an angle to each other or with units arranged around a central element
    • F28D1/0435—Combination of units extending one behind the other
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D1/00—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators
    • F28D1/02—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid
    • F28D1/04—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with tubular conduits
    • F28D1/047—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with tubular conduits the conduits being bent, e.g. in a serpentine or zig-zag
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D1/00—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators
    • F28D1/02—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid
    • F28D1/04—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with tubular conduits
    • F28D1/053—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with tubular conduits the conduits being straight
    • F28D1/0535—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with tubular conduits the conduits being straight the conduits having a non-circular cross-section
    • F28D1/05366—Assemblies of conduits connected to common headers, e.g. core type radiators
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D5/00—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, using the cooling effect of natural or forced evaporation
    • F28D5/02—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, using the cooling effect of natural or forced evaporation in which the evaporating medium flows in a continuous film or trickles freely over the conduits
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D7/00—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
    • F28D7/0066—Multi-circuit heat-exchangers, e.g. integrating different heat exchange sections in the same unit or heat-exchangers for more than two fluids
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F1/00—Tubular elements; Assemblies of tubular elements
    • F28F1/02—Tubular elements of cross-section which is non-circular
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F1/00—Tubular elements; Assemblies of tubular elements
    • F28F1/10—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses
    • F28F1/12—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element
    • F28F1/24—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element and extending transversely
    • F28F1/32—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element and extending transversely the means having portions engaging further tubular elements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F9/00—Casings; Header boxes; Auxiliary supports for elements; Auxiliary members within casings
    • F28F9/26—Arrangements for connecting different sections of heat-exchange elements, e.g. of radiators
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2339/00—Details of evaporators; Details of condensers
    • F25B2339/04—Details of condensers
    • F25B2339/041—Details of condensers of evaporative condensers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2500/00—Problems to be solved
    • F25B2500/01—Geometry problems, e.g. for reducing size
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28C—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA COME INTO DIRECT CONTACT WITHOUT CHEMICAL INTERACTION
    • F28C1/00—Direct-contact trickle coolers, e.g. cooling towers
    • F28C1/14—Direct-contact trickle coolers, e.g. cooling towers comprising also a non-direct contact heat exchange
    • F28C2001/145—Direct-contact trickle coolers, e.g. cooling towers comprising also a non-direct contact heat exchange with arrangements of adjacent wet and dry passages
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D1/00—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators
    • F28D1/02—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid
    • F28D1/04—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with tubular conduits
    • F28D1/053—Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, in which the other heat-exchange medium is a large body of fluid, e.g. domestic or motor car radiators with heat-exchange conduits immersed in the body of fluid with tubular conduits the conduits being straight
    • F28D1/05308—Assemblies of conduits connected side by side or with individual headers, e.g. section type radiators
    • 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
    • Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
    • Y02B30/70—Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Definitions

  • the present invention relates to evaporative condensers and coolers.
  • evaporative condensers receive superheated refrigerant gas from a cooling/refrigeration system compressor and
  • the evaporative condensers include a series of round or slightly elliptical serpentine tubes through which the refrigerant passes. Water is flowed over the tubes containing the refrigerant, allowing heat to be transferred from the refrigerant to the water via indirect heat exchange and causing the superheated refrigerant gas to condense to liquid. The heated water in turn is cooled by direct heat exchange with ambient air as the water and ambient air pass over the tubes and/or through fill material.
  • the present invention is a new design for evaporative refrigerant condensers including an indirect refrigerant condensing tube bundle heat exchanger with single pass (no serpentine) extremely narrow elliptical tubes (ratios of tube height to tube width of 3 : 1 to 16: 1) to increase the refrigerant velocity (void fraction).
  • the preferred tube width of the tubes of the invention is
  • the preferred tube width of the tubes of the invention is approximately 0.025 inches to 0.125 inches, outside diameter, with tube height about 0.3 inches to 0.4 inches, outside diameter (vertical axis of ellipse).
  • Each single pass tube terminates at one end at an inlet refrigerant header and at the other end at an outlet refrigerant header.
  • the tubes may be galvanized or stainless steel.
  • the tubes may be provided with a flared inlet to reduce inlet refrigerant pressure loss.
  • tube spacing may be approximately 0.5 inches to .75 inches, center to center.
  • each tube may be offset vertically relative to adjacent tubes to reduce air dP loss so that adjacent tubes nest into one-another.
  • This design reduces the cross sectional refrigerant flow area significantly, thus significantly reducing the required refrigerant charge, while maintaining the external heat exchange surface and thus heat exchange capacity, resulting in an unexpected increase in efficiency of more than 20% relative to the same device with serpentine elliptical tubes.
  • the refrigerant condensing tube bundle of the invention may be substituted for the serpentine coil from a standard evaporative closed circuit cooler/condenser.
  • the refrigerant condensing tube bundle described above may be combined with (placed into) an otherwise standard counterflow direct evaporative cooling tower to create a new type of evaporative refrigerant condenser/cooling tower.
  • the tube bundle may be used as the structural support for fill, supporting various amounts of fill height, for example, but not limited to, 6 inches, , 1.5', 2', 2.5', 3', 3.5', 4' or more of film fill height, or any amounts in between.
  • the bottom fill bundles should preferably be run perpendicular to the condenser tubes for best water distributions on the tubes.
  • Standard cooling tower nozzle arrangements may be used with water flow rates as low as 2gpm/sf, with preferable amounts of 4 gpm/sf to 10 gpm/sf, and more preferably from around 5 gpm/sf to 7 gpm/sf.
  • the tubes in the tube bundle may have a slight slope from horizontal to allow for drainage of liquid refrigerant.
  • lengths of the tubes of the tube bundle may run either long or short way across the tower depending on thermal and refrigerant load.
  • the tube bundle of the invention may be used in a counterflow closed circuit cooler arrangement in which the fan, water distribution nozzles, heat and mass exchange fill and air inlets are all positioned above a water redistribution basin, which in turn is positioned above a closed circuit cooler coil of the invention.
  • This embodiment produces a substantial reduction in height due to the lack of serpentine tube bends in the tube bundle of the invention.
  • the tube spacing of the present invention used in a counterflow closed circuit cooler can be much tighter with less space between tubes, since only water and no air needs to flow between tubes.
  • the coil bundle of the invention may be located just above the fill and below the spray nozzles.
  • the tube bundle of the invention may be used with various crossflow arrangements.
  • the tube bundle is located above the crossflow fill and below the nozzle distribution system and air flows downward through the tubes before exiting to the fan plenum.
  • the tube bundles of the invention may be located above, below and in the middle of the crossflow fill. According to this embodiment, no air passes over the tubes, only water, as the cooled water flows from one fill section down to the next.
  • Figure 1 is a cross-sectional view of a tube according to an embodiment of the invention.
  • Figure 2 is a cross-sectional view of a tube according to another embodiment of the invention.
  • Figure 3 is a perspective view of a tube bundle according to an embodiment of the invention
  • Figure 4 is a top/overhead view of the embodiment shown in Figure 3.
  • Figure 5 is a side view of the embodiment shown in Figures 3 and 4.
  • Figure 6 is an end view of the embodiment shown in Figures 3-5.
  • Figure 7A is a representation of a prior art closed circuit cooler/condenser with serpentine coil.
  • Figure 7B is a representation of a closed circuit cooler/condenser with an ultra-narrow elliptical tube bundle according to an embodiment of the invention.
  • Figure 8A is a representation of a prior art counterflow direct evaporative cooling tower.
  • Figure 8B is a representation of a counterflow indirect evaporative refrigerant condenser/cooling tower according to an embodiment of the invention.
  • Figure 8C is a representation of different counterflow indirect evaporative refrigerant condenser/cooling tower according to an embodiment of the invention.
  • Figure 9A is a representation of a prior art closed circuit cooler.
  • Figure 9B is a representation of closed circuit cooler according to an embodiment of the invention.
  • Figure 1 OA is a representation of a prior art induced draft evaporative condenser/cooler.
  • Figure 10B is a representation of an induced draft evaporative
  • Figure IOC is a representation of another embodiment according to the invention.
  • Figure 10D is a representation of a further embodiment according to the invention.
  • Figure 10E is a representation of yet another embodiment of the invention.
  • Figure 1 shows a cross-section of a condenser tube according to an
  • the tubes of the invention are formed in the shape of an extreme ellipse, with the major axis of the tube at least 3x the minor axis.
  • the height of the tube (major axis) is at least 1.4 inches (outer diameter)
  • the width of the tube (minor axis) is no greater than 0.5 inches (outer diameter).
  • a preferred embodiment is shown in Figure 2, in which the ratio of the major axis to the minor axis is 6.4: 1.
  • the minor axis may be 0.1 inches to 0.25 inches
  • the major axis may be 1.4 inches to 1.6 inches with ratios of major axis to minor axis of 3 : 1 to 16: 1.
  • the tubes of the invention may be arranged in rows of parallel single pass tubes, each tube running from an inlet header to an outlet header.
  • the embodiment shown in Figures 3-6 shows multiple inlet and outlet headers, with each row of tubes having its own set of headers.
  • a single header may be provided at each end of the bundle, with all tubes from all rows terminating at one end at a single inlet header, and terminating at the other end at a single outlet header.
  • the lack of return bends as in the prior art serpentine tubes substantially reduces the height of the tube bundle for the same capacity.
  • Horizontal tube spacing is preferably 0.5 inches to .75 inches, center to center.
  • the spacing between adjacent tube sides is preferably 0.25 to .65 inches.
  • Vertical tube spacing is preferably 0.5 inches to 2.0 inches, center to center.
  • Figure 7B shows a closed circuit cooler/condenser in which the prior art serpentine coil has been replaced with an ultra-narrow elliptical tube bundle according to tn embodiment of the invention.
  • Standard cooling tower nozzles distribute water over the ultra- narrow elliptical tube bundle of the invention, and the water collects in a basin at the bottom of the device from which it is pumped back to the nozzles.
  • Ambient air is drawn into the plenum of the device at the bottom under the action of a fan and is drawn up through the tube bundle to exit the device from the top.
  • Figure 8B shows a counterflow indirect evaporative refrigerant
  • condenser/cooling tower in which a refrigerant condensing tube bundle according to the invention has been placed into a standard counterflow direct evaporative cooling tower.
  • the tube bundle can act as the structural support for the fill, the sheets of which run perpendicular to the condenser tubes.
  • Standard cooling tower nozzles distribute water over the fill, and the water collects in a basin at the bottom of the device from which it is pumped back to the nozzles. Ambient air is drawn into the plenum of the device at the bottom under the action of a fan and is drawn up through the tube bundle and the fill to exit the device from the top.
  • Figure 8B shows the tubes run parallel to the longitudinal axis of the tower.
  • Figure 8C shows an embodiment in which the tubes run perpendicular to the longitudinal axis of the tower.
  • Figure 9B shows the tube bundle of the invention in an open cooling tower embodiment having a closed circuit water-to-fluid heat exchanger below.
  • the tube bundle is located at the bottom of the device, and air is drawn into a plenum of the device through side openings located above the tube bundle. Air is drawn through the fill and forced out through the top of the device.
  • Spray nozzles from a water distribution system spray water over the fill. The water is collected in a tray and then redistributed over the tube bundle, cooling the fluid therein via indirect heat exchange.
  • the water collects in a basin at the bottom of the devices and is then pumped back to the spray nozzles. Since no air is directed over the tubes, the tube spacing can be much tighter, and the tube bundle of the present invention allows for much tighter spacing with the extreme elliptical shape and the lack of return bends.
  • Figure 10B shows a tube bundle according to the invention in an induced draft evaporative condenser unit with crossflow fill.
  • the tube bundle is located directly beneath the spray nozzles of the water distribution system, and the fill is located below the tube bundle. Air enters the device through the sides at the bottom, adjacent the fill, as well as through the top above the tube bundle. Air flows downward through the tubes before exiting to the fan plenum. Water flows over the tube bundle and then over the fill to collect in the basin, from which it is pumped back to the water distribution system.
  • the tube bundles of the invention may be located above (Figure IOC), below ( Figure 10D) and/or in the middle ( Figure 10E) of the crossflow fill. According to these embodiments, only water is directed over the tubes, and no air flow is directed over the tubes.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Thermal Sciences (AREA)
  • Geometry (AREA)
  • Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)

Abstract

A tube bundle for an evaporative refrigerant condenser having a plurality of straight single pass tubes extending between a refrigerant inlet header and a refrigerant outlet header, said tubes having a cross-sectional shape in the form of an ellipse having a major axis and a minor axis, wherein said major axis is longer than said minor axis by a factor of 3 to 7, wherein the amount of required refrigerant charge for a particular heat exchange capacity is substantially and unexpectedly reduced resulting in a substantial and unexpected increase in efficiency.

Description

ULTRA NARROW CHANNEL ULTRA LOW REFRIGERANT CHARGE
EVAPORATIVE CONDENSER
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
[0001] The present invention relates to evaporative condensers and coolers.
DESCRIPTION OF THE BACKGROUND
[0002] In certain cooling/refrigeration system, evaporative condensers receive superheated refrigerant gas from a cooling/refrigeration system compressor and
cool/condense it to refrigerant liquid, which condensed refrigerant liquid is then return to a cooling/refrigeration system evaporator for cooling/refrigeration of a desired space. The evaporative condensers include a series of round or slightly elliptical serpentine tubes through which the refrigerant passes. Water is flowed over the tubes containing the refrigerant, allowing heat to be transferred from the refrigerant to the water via indirect heat exchange and causing the superheated refrigerant gas to condense to liquid. The heated water in turn is cooled by direct heat exchange with ambient air as the water and ambient air pass over the tubes and/or through fill material.
SUMMARY OF THE INVENTION
[0003] The present invention is a new design for evaporative refrigerant condensers including an indirect refrigerant condensing tube bundle heat exchanger with single pass (no serpentine) extremely narrow elliptical tubes (ratios of tube height to tube width of 3 : 1 to 16: 1) to increase the refrigerant velocity (void fraction). For example, for a nominal tube diameter 1" round tube, the preferred tube width of the tubes of the invention is
approximately 0.1 inches to 0.5 inches, outside diameter, with tube height about 1.4 inches to 1.6 inches, outside diameter (vertical axis of ellipse). Similarly, at the other end of nominal tube diameter spectrum, for a nominal diameter 1/4" round tube, the preferred tube width of the tubes of the invention is approximately 0.025 inches to 0.125 inches, outside diameter, with tube height about 0.3 inches to 0.4 inches, outside diameter (vertical axis of ellipse).
[0004] Each single pass tube terminates at one end at an inlet refrigerant header and at the other end at an outlet refrigerant header. The tubes may be galvanized or stainless steel. The tubes may be provided with a flared inlet to reduce inlet refrigerant pressure loss.
According to a preferred embodiment, tube spacing may be approximately 0.5 inches to .75 inches, center to center. According to another embodiment, each tube may be offset vertically relative to adjacent tubes to reduce air dP loss so that adjacent tubes nest into one-another.
[0005] This design reduces the cross sectional refrigerant flow area significantly, thus significantly reducing the required refrigerant charge, while maintaining the external heat exchange surface and thus heat exchange capacity, resulting in an unexpected increase in efficiency of more than 20% relative to the same device with serpentine elliptical tubes.
[0006] According to a first embodiment of the invention, the refrigerant condensing tube bundle of the invention may be substituted for the serpentine coil from a standard evaporative closed circuit cooler/condenser.
[0007] According to another embodiment of the invention, the refrigerant condensing tube bundle described above may be combined with (placed into) an otherwise standard counterflow direct evaporative cooling tower to create a new type of evaporative refrigerant condenser/cooling tower. According to various alternative embodiments, the tube bundle may be used as the structural support for fill, supporting various amounts of fill height, for example, but not limited to, 6 inches, , 1.5', 2', 2.5', 3', 3.5', 4' or more of film fill height, or any amounts in between. According to these tube-bundle-as-fill-support embodiments, the bottom fill bundles should preferably be run perpendicular to the condenser tubes for best water distributions on the tubes. Standard cooling tower nozzle arrangements may be used with water flow rates as low as 2gpm/sf, with preferable amounts of 4 gpm/sf to 10 gpm/sf, and more preferably from around 5 gpm/sf to 7 gpm/sf.
[0008] According to some embodiments, the tubes in the tube bundle may have a slight slope from horizontal to allow for drainage of liquid refrigerant.
[0009] According to various different embodiments of lengths of the tubes of the tube bundle may run either long or short way across the tower depending on thermal and refrigerant load.
[0010] According to an alternative embodiment, the tube bundle of the invention may be used in a counterflow closed circuit cooler arrangement in which the fan, water distribution nozzles, heat and mass exchange fill and air inlets are all positioned above a water redistribution basin, which in turn is positioned above a closed circuit cooler coil of the invention. This embodiment produces a substantial reduction in height due to the lack of serpentine tube bends in the tube bundle of the invention. The tube spacing of the present invention used in a counterflow closed circuit cooler can be much tighter with less space between tubes, since only water and no air needs to flow between tubes.
[0011] According to further alternative counterflow embodiments, the coil bundle of the invention may be located just above the fill and below the spray nozzles.
[0012] According to further embodiments, the tube bundle of the invention may be used with various crossflow arrangements. According to one such embodiment, the tube bundle is located above the crossflow fill and below the nozzle distribution system and air flows downward through the tubes before exiting to the fan plenum. According to another such embodiment, the tube bundles of the invention may be located above, below and in the middle of the crossflow fill. According to this embodiment, no air passes over the tubes, only water, as the cooled water flows from one fill section down to the next. [0013] A more detailed description of the invention is set forth below with reference to the following figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 is a cross-sectional view of a tube according to an embodiment of the invention.
[0015] Figure 2 is a cross-sectional view of a tube according to another embodiment of the invention.
[0016] Figure 3 is a perspective view of a tube bundle according to an embodiment of the invention
[0017] Figure 4 is a top/overhead view of the embodiment shown in Figure 3.
[0018] Figure 5 is a side view of the embodiment shown in Figures 3 and 4.
[0019] Figure 6 is an end view of the embodiment shown in Figures 3-5.
[0020] Figure 7A is a representation of a prior art closed circuit cooler/condenser with serpentine coil.
[0021] Figure 7B is a representation of a closed circuit cooler/condenser with an ultra-narrow elliptical tube bundle according to an embodiment of the invention.
[0022] Figure 8A is a representation of a prior art counterflow direct evaporative cooling tower.
[0023] Figure 8B is a representation of a counterflow indirect evaporative refrigerant condenser/cooling tower according to an embodiment of the invention.
[0024] Figure 8C is a representation of different counterflow indirect evaporative refrigerant condenser/cooling tower according to an embodiment of the invention.
[0025] Figure 9A is a representation of a prior art closed circuit cooler.
[0026] Figure 9B is a representation of closed circuit cooler according to an embodiment of the invention. [0027] Figure 1 OA is a representation of a prior art induced draft evaporative condenser/cooler.
[0028] Figure 10B is a representation of an induced draft evaporative
condenser/cooler according to an embodiment of the invention.
[0029] Figure IOC is a representation of another embodiment according to the invention.
[0030] Figure 10D is a representation of a further embodiment according to the invention.
[0031] Figure 10E is a representation of yet another embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0032] Figure 1 shows a cross-section of a condenser tube according to an
embodiment of the invention. As shown in Figure 1, the tubes of the invention are formed in the shape of an extreme ellipse, with the major axis of the tube at least 3x the minor axis. According to preferred embodiments, the height of the tube (major axis) is at least 1.4 inches (outer diameter), and the width of the tube (minor axis) is no greater than 0.5 inches (outer diameter). A preferred embodiment is shown in Figure 2, in which the ratio of the major axis to the minor axis is 6.4: 1. According to further preferred embodiments, the minor axis may be 0.1 inches to 0.25 inches, and the major axis may be 1.4 inches to 1.6 inches with ratios of major axis to minor axis of 3 : 1 to 16: 1.
[0033] Referring to Figures 3-6, the tubes of the invention may be arranged in rows of parallel single pass tubes, each tube running from an inlet header to an outlet header. The embodiment shown in Figures 3-6 shows multiple inlet and outlet headers, with each row of tubes having its own set of headers. According to an alternative embodiment, a single header may be provided at each end of the bundle, with all tubes from all rows terminating at one end at a single inlet header, and terminating at the other end at a single outlet header. [0034] In either case, the lack of return bends as in the prior art serpentine tubes substantially reduces the height of the tube bundle for the same capacity. Horizontal tube spacing is preferably 0.5 inches to .75 inches, center to center. The spacing between adjacent tube sides is preferably 0.25 to .65 inches. Vertical tube spacing is preferably 0.5 inches to 2.0 inches, center to center.
[0035] Figure 7B shows a closed circuit cooler/condenser in which the prior art serpentine coil has been replaced with an ultra-narrow elliptical tube bundle according to tn embodiment of the invention. Standard cooling tower nozzles distribute water over the ultra- narrow elliptical tube bundle of the invention, and the water collects in a basin at the bottom of the device from which it is pumped back to the nozzles. Ambient air is drawn into the plenum of the device at the bottom under the action of a fan and is drawn up through the tube bundle to exit the device from the top.
[0036] Figure 8B shows a counterflow indirect evaporative refrigerant
condenser/cooling tower according to an embodiment of the invention in which a refrigerant condensing tube bundle according to the invention has been placed into a standard counterflow direct evaporative cooling tower. As shown in Figure 8B, the tube bundle can act as the structural support for the fill, the sheets of which run perpendicular to the condenser tubes. Standard cooling tower nozzles distribute water over the fill, and the water collects in a basin at the bottom of the device from which it is pumped back to the nozzles. Ambient air is drawn into the plenum of the device at the bottom under the action of a fan and is drawn up through the tube bundle and the fill to exit the device from the top. According to the embodiment shown in Figure 8B, the tubes run parallel to the longitudinal axis of the tower. Figure 8C shows an embodiment in which the tubes run perpendicular to the longitudinal axis of the tower. [0037] Figure 9B shows the tube bundle of the invention in an open cooling tower embodiment having a closed circuit water-to-fluid heat exchanger below. As shown in Figure 9B, the tube bundle is located at the bottom of the device, and air is drawn into a plenum of the device through side openings located above the tube bundle. Air is drawn through the fill and forced out through the top of the device. Spray nozzles from a water distribution system spray water over the fill. The water is collected in a tray and then redistributed over the tube bundle, cooling the fluid therein via indirect heat exchange. The water collects in a basin at the bottom of the devices and is then pumped back to the spray nozzles. Since no air is directed over the tubes, the tube spacing can be much tighter, and the tube bundle of the present invention allows for much tighter spacing with the extreme elliptical shape and the lack of return bends.
[0038] Figure 10B shows a tube bundle according to the invention in an induced draft evaporative condenser unit with crossflow fill. The tube bundle is located directly beneath the spray nozzles of the water distribution system, and the fill is located below the tube bundle. Air enters the device through the sides at the bottom, adjacent the fill, as well as through the top above the tube bundle. Air flows downward through the tubes before exiting to the fan plenum. Water flows over the tube bundle and then over the fill to collect in the basin, from which it is pumped back to the water distribution system.
[0039] According to further embodiments, the tube bundles of the invention may be located above (Figure IOC), below (Figure 10D) and/or in the middle (Figure 10E) of the crossflow fill. According to these embodiments, only water is directed over the tubes, and no air flow is directed over the tubes.
[0040] Having now fully set forth the preferred embodiments and certain
modifications of the concept underlying the present invention, various other embodiments as well as certain variations and modifications of the embodiments herein shown and described will obviously occur to those skilled in the art upon becoming familiar with said underlying concept. It should be understood, therefore, that the invention may be practiced otherwise than as specifically set forth herein.

Claims

Claims:
1. A tube bundle for an evaporative refrigerant condenser comprising a refrigerant inlet header, a refrigerant outlet heater, and a plurality of straight single pass tubes extending between said refrigerant inlet header and said refrigerant outlet header, said tubes having a cross-sectional shape in the form of an ellipse having a major axis and a minor axis, wherein said major axis is longer than said minor axis by a factor of 3 to 10.
2. The tube bundle according to claim 1 wherein said major axis has a length of 1.4 inches to 1.7 inches, outside tube diameter.
3. The tube bundle according to claim 1, wherein said minor axis has a width of 0.1 inches to 0.25 inches, outside tube diameter.
4. The tube bundle according to claim 1, wherein said major axis has a length of 1.4 inches to 1.7 inches, outside tube diameter and wherein said minor axis has a width of 0.1 inches to 0.25 inches, outside tube diameter.
5. The tube bundle according to claim 1, wherein each tube is spaced from each horizontally adjacent tube by 0.5 inches to .75 inches, center to center.
6. The tube bundle according to claim, wherein each tube is spaced from each vertically adjacent tube by x inches to y inches, center to center.
7. An evaporative refrigerant condenser or closed circuit fluid cooler comprising: a housing;
a fan located near a top of said housing to draw air into said housing and force it through said top of said housing;
a water distribution system, including a pump and water distribution nozzles, said water distribution nozzles located beneath said fan;
a tube bundle located beneath said fan, said tube bundle comprising a refrigerant inlet header, a refrigerant outlet heater, and a plurality of straight single pass tubes extending between said refrigerant inlet header and said refrigerant outlet header, said tubes having a cross-sectional shape in the form of an ellipse having a major axis and a minor axis, wherein said major axis is longer than said minor axis by a factor of 3 to 10;
a plenum located beneath said tube bundle,
a water basin located at a bottom of said plenum for collecting water distributed from said water distribution system;
said pump configured to draw water from said water basin and force it through said water distribution nozzles;
an air inlet on at least one side of said housing adjacent said plenum to allow entry of air drawn by said fan.
8. The evaporative refrigerant condenser or closed circuit fluid cooler according to claim 7, further comprising a direct heat exchange fill located between said water distribution nozzles for facilitating direct heat exchange between said air and said water.
9. The evaporative refrigerant condenser or closed circuit fluid cooler according to claim 7, wherein said direct heat exchange fill rests directly on said tube bundle, and said tube bundle provides structural support for said direct heat exchange fill.
10. A counterflow closed circuit cooler or refrigerant condenser comprising:
a housing;
a fan located near a top of said housing to draw air into said housing and force it through said top of said housing;
a water distribution system, including a pump and water distribution nozzles, said water distribution nozzles located beneath said fan;
a direct heat exchange fill located beneath said water distribution nozzles for facilitating direct heat exchange between said air and said water;
a plenum located beneath said direct heat exchange fill, a redistribution basin located beneath said plenum and configured to collect water distributed from said water distribution nozzles and redistributed it to a lower portion of said housing;
a tube bundle located beneath said redistribution basin, said tube bundle comprising a refrigerant inlet header, a refrigerant outlet heater, and a plurality of straight single pass tubes extending between said refrigerant inlet header and said refrigerant outlet header, said tubes having a cross-sectional shape in the form of an ellipse having a major axis and a minor axis, wherein said major axis is longer than said minor axis by a factor of 3 to 10;
a water basin located at a bottom of said housing for collecting water distributed from sai d water di stributi on sy stem ;
said pump configured to draw water from said water basin and force it through said water distribution nozzles;
an air inlet on a side of said housing adjacent said plenum to allow entry of air drawn by said fan.
11. An induced draft evaporative condenser or closed circuit cooler comprising:
a housing;
a fan located near a top of said housing to draw air into said housing and force it through said top of said housing;
a water distribution system, including a pump and water distribution nozzles, said water distribution nozzles located adjacent said fan;
a tube bundle located beneath said water distribution nozzles, said tube bundle comprising a refrigerant inlet header, a refrigerant outlet heater, and a plurality of straight single pass tubes extending between said refrigerant inlet header and said refrigerant outlet header, said tubes having a cross-sectional shape in the form of an ellipse having a major axis and a minor axis, wherein said major axis is longer than said minor axis by a factor of 3 to 10;
a direct heat exchange fill located beneath said tube bundle for facilitating direct heat exchange between said air and said water;
a plenum located beneath said fan,
a water basin located at a bottom of said housing for collecting water distributed from said water distribution system;
said pump configured to draw water from said water basin and force it through said water distribution nozzles;
an air inlet on a bottom side of said housing adjacent said fill to allow entry of air drawn by said fan.
EP17832023.0A 2016-07-22 2017-07-24 Ultra narrow channel ultra low refrigerant charge evaporative condenser Withdrawn EP3488169A4 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US201662365435P 2016-07-22 2016-07-22
PCT/US2017/043557 WO2018018049A1 (en) 2016-07-22 2017-07-24 Ultra narrow channel ultra low refrigerant charge evaporative condenser

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EP3488169A1 true EP3488169A1 (en) 2019-05-29
EP3488169A4 EP3488169A4 (en) 2020-03-25

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Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4755331A (en) * 1986-12-02 1988-07-05 Evapco, Inc. Evaporative heat exchanger with elliptical tube coil assembly
DK2722627T3 (en) * 2009-11-04 2016-10-10 Evapco Inc Hybrid heat exchanging.
US10655918B2 (en) * 2016-10-12 2020-05-19 Baltimore Aircoil Company, Inc. Indirect heat exchanger having circuit tubes with varying dimensions

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