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
  • F25B19/00—Machines, plants or systems, using evaporation of a refrigerant but without recovery of the vapour
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
  • F24F5/00—Air-conditioning systems or apparatus not covered by F24F1/00 or F24F3/00, e.g. using solar heat or combined with household units such as an oven or water heater
  • F24F5/0007—Air-conditioning systems or apparatus not covered by F24F1/00 or F24F3/00, e.g. using solar heat or combined with household units such as an oven or water heater cooling apparatus specially adapted for use in air-conditioning
  • F24F5/0035—Air-conditioning systems or apparatus not covered by F24F1/00 or F24F3/00, e.g. using solar heat or combined with household units such as an oven or water heater cooling apparatus specially adapted for use in air-conditioning using evaporation
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
  • F24F6/00—Air-humidification, e.g. cooling by humidification
  • F24F6/02—Air-humidification, e.g. cooling by humidification by evaporation of water in the air
  • F24F6/04—Air-humidification, e.g. cooling by humidification by evaporation of water in the air using stationary unheated wet elements
• • 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
  • F25B49/00—Arrangement or mounting of control or safety devices
• • 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
  • F25B2341/00—Details of ejectors not being used as compression device; Details of flow restrictors or expansion valves
  • F25B2341/001—Ejectors not being used as compression device
• • 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
  • F25B2600/00—Control issues
  • F25B2600/25—Control of valves
  • F25B2600/2515—Flow valves
• • 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
  • F25B2700/00—Sensing or detecting of parameters; Sensors therefor
  • F25B2700/04—Refrigerant level
• • 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
  • F25B41/00—Fluid-circulation arrangements
• • 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]
  • Y02B30/54—Free-cooling systems

Definitions

• the present invention is directed to improvements in evaporative cooling systems, and particularly to direct evaporative cooling systems.
• Evaporative cooling systems can be considered conditioning systems that utilize thermodynamic laws to cool a fluid.
• a change of a fluid from a liquid phase to a vapor phase can result in a reduction in temperature due to the heat of vaporization involved in the phase change.
• Evaporative coolers typically include a contact pad or media made of structured corrugated fill composed of cellulose, glass fiber, or other media. This fill is used to act as an extended surface for the contact of cooling fluid with the air that passes through the media.
• FIG. 3 represents a schematic of a typical direct evaporative cooler 100.
• Water or another suitable cooling liquid is recirculated from a reservoir or sump 110 through a supply line 1 12 to a distributor 1 16 using a pump 1 14.
• Distributor 116 evenly distributes the supplied water over a heat exchanger, such as evaporative pad 1 18.
• Supply air 124 is passed through the pad, where it is cooled and humidified to exit as cooled air 126.
• the water fed from distributor 16 flows down and through the pad and evaporates as it meets the warm supply air 124.
• a bleed stream controlled by valve 120 for example, is removed from the system through a bleed or drain line to drain 122 to control mineral build-up in the water.
• Fresh make-up water is added as needed from water supply 128 to replace the water evaporated and bled.
• the make-up water can be controlled by a float valve (not shown) provided in the reservoir 110.
• the present invention can improve the efficiency and effectiveness of evaporative cooling systems by utilizing energy available in the incoming water supply to create a recirculating loop to increase the water applied to the top of the media.
• an evaporative cooling system includes a heat exchange medium for receiving cooling fluid to cool supply air flowing past the heat exchange medium, a cooling fluid source for supplying fresh cooling fluid, a supply line communicating with the cooling fluid source for supplying the cooling fluid to the heat exchange medium, a return reservoir for collecting the cooling fluid supplied to the heat exchange medium, and a pump provided in the supply line for recirculating the cooling fluid collected in the reservoir into the supply line so as to provide recirculated cooling fluid along with fresh cooling fluid to the heat exchange medium.
• a gas conditioning system in another aspect of the present invention, includes a conditioning unit configured to condition a gas flowing therethrough, the conditioning unit utilizing a conditioning fluid to condition the flowing gas, a conditioning fluid source for supplying fresh conditioning fluid, a supply line communicating with the conditioning fluid source for supplying the conditioning fluid to the conditioning unit, a return reservoir for collecting the conditioning fluid supplied to the conditioning unit, and a pump provided in the supply line for recirculating the conditioning fluid collected in the return reservoir into the supply line so as to provide recirculated conditioning fluid along with fresh conditioning fluid to the conditioning unit.
• a method of cooling supply air in an evaporative cooling system includes supplying fresh cooling fluid from a cooling fluid source to a heat exchange medium through a supply line, collecting at least a portion of the fresh cooling fluid supplied to and having passed through the heat exchange medium in a return reservoir, recirculating the collected cooling fluid to the supply line to be supplied along with the fresh cooling fluid, and flowing the supply air through the primary heat exchange medium and the secondary heat exchange medium.
• FIG. 1 is a schematic view of an evaporative cooling system of a first embodiment of the present invention.
• Figure 2 is a view of an example of an eductor used in the evaporative cooling system of the present invention.
• Figure 3 is a perspective and schematic view of a typical direct evaporative cooling system.
• Figure 4 is a graph showing cooling effectiveness of evaporative media useable with the present invention.
• Figure 5 is a graph showing pressure drop of evaporative media useable with the present invention.
• cooling fluid flow rate applied to the top surface of the evaporative pad in an evaporative cooling system can influence the selection of the cooling fluid flow rate applied to the top surface of the evaporative pad in an evaporative cooling system.
• sufficient cooling fluid is applied to the media so that at no location within the media does all of the cooling fluid evaporate before it can reach the bottom of the media.
• the mineral content is concentrated in the remaining cooling fluid.
• Sufficient excess flow must be applied to ensure that the mineral content in no region becomes high enough that scale is deposited or precipitates out on the surface of the media. Scale deposits can eventually foul the surface and prevent sufficient or even air flow through the media.
• typical direct evaporative cooling systems are generally fitted with a recirculating pump so that a given volume of water is repeatedly applied to the pad surface via the top area. Evaporated water is replenished in a sump with fresh water. Without any other control, the mineral content in the recirculated water in the system would continue to increase until the minerals precipitate out and cause fouling. To counteract this effect, a bleed-off stream is usually added to the system.
• This bleed off may be implemented in a very simple fashion, with a manually set valve to remove a predetermined amount of water, or with a sophisticated control system that monitors the recirculated water properties and allows bleed-off to occur in a controlled manner to maintain a predetermined quality. In both cases, fresh water is used to refill the sump and replace the bled- off water. This has the net effect of reducing the mineral content in the water.
• the amount of bleed required to control the recirculated water quality is based on many factors involving the incoming water quality and its ability to be "cycled up” or concentrated without mineral precipitation.
• a good explanation of how the water quality affects the scaling indexes and the determination of an appropriate Cycles of Concentration (CoC) can be found in Munters Bulletin EB-WTGT-0406, which is also incorporated herein by reference.
• Cycles of concentration is a measure that compares the level of solids of the recirculating water to the level of solids of the original raw make-up water. For example, if the circulating water has four times the solids concentration than that of the make-up water, then the cycles of concentration is 4.
• a lower cost system termed “direct water,” does away with the pump and applies water directly from the water source to the top of the pad. These systems attempt to use as little water as possible by setting the flow rate to the lowest possible flow that will achieve even and complete media coverage. However, this generally requires that substantial excess water be applied as compared to the evaporation rate, resulting in a significant waste of water.
• the present invention is directed to a direct water system which uses energy available in an incoming cooling fluid supply to create a recirculating loop to increase the cooling fluid applied to the top of the media. This is accomplished through the use of an eductor, or venturi pump, to entrain water from the sump of the system into the direct water stream to increase the flow to the top of the media.
• FIG. 1 is a schematic view of an evaporative cooling system of a first embodiment of the present invention.
• Evaporative cooling system 200 utilizes a typical direct evaporative cooler described with respect to Figure 3.
• the system of the first embodiment of the present invention includes an evaporative pad (evaporative media) or heat exchanger 218, a sump or return reservoir 210, a supply line 212, and a distributor or spray head 216. These components are used to supply water or another suitable cooling fluid to the top surface of the evaporative pad 218 and allow the cooling fluid to flow downward over the side and middle surfaces of the pad.
• the cooling water flows down the evaporative pad or heat exchanger 218 and is collected in return reservoir 210.
• the fresh or raw cooling fluid is supplied from a source 228, such as municipal water, directly to the supply line 218 and then to distributor or spray head 216 and onto the evaporative pad. After the cooling fluid flows down the evaporative pad 218 and is collected in return reservoir 210, it can be recirculated back to the pad.
• an eductor, jet pump, or venturi pump 230 is provided in the supply line 212.
• Eductor 230 is connected to return reservoir 210 by recirculating line 232.
• An enlarged view of an example of the eductor 230 is shown in Figure 2.
• Evaporative pad 218 can be CELdek® or GLASdek® media available from Munters Corp., and the size of the media can be selected based on the needs of the particular system. Examples of cooling effectiveness and pressure drop per selected thicknesses over various parameters are shown in the graphs of Figures 4 and 5. Appropriate thicknesses can be selected in view of these criteria.
• eductor 230 includes an inlet port 230-1, an outlet port 230-2, a suction port 230-3, a nozzle 230-4, and a diffuser 230-5.
• Eductor 230 is provided in line supply line 212 such that inlet port 230-1 is connected to an upstream side of the supply line and outlet port 230-2 is connected to a downstream side thereof.
• Recirculating line 232 is connected to the suction port of the eductor.
• an eductor Given a 50 psi water supply, an eductor can be designed to more than triple the volume of flow to the top of the evaporative media.
• the operation of an example of an eductor is described in Penberthy Jet Pump Technical Data Bulletin 1200 issued in May 1987, which is incorporated herein by reference.
• the chart on page 6 demonstrates that given a lift requirement of 10' of discharge head and utilizing a 50 psi water source, an entrained rate or suction capacity (Qs) of nearly double the motive rate (Qm) of inlet water can be achieved, in this case 33 gpm entrained with 17 gpm motive for a nominal sized eductor.
• the system may also be installed with an overflow line 234 to drain 236 to allow an overflow or bleed stream.
• This overflow or bleed stream can measured by a flow sensor 238 in overflow line 234 and the measured flow can then be compared to an inflow of source water from source 228, either measured directly through another sensor (not shown), or indirectly through a timer and assumed flow rate. The inflow and overflow values can then be used to calculate a Cycles of Concentration.
• a supply valve 240 is provided in supply line 212 upstream of eductor 230.
• Supply valve 240 can be variable or simply on/off and be controllable by a controller 242.
• Controller 242 can be any suitable systems microcontroller. The supply valve can be adjusted according to system conditions. A signal from flow sensor 238 to controller 242 can be analyzed so that controller 242 controls supply valve 240 to increase, decrease, or pulse the cooling fluid as the amount of overflow changes.
• the system is evaporating 59.2 kg/hr of water (10,000 m 3 /hr 1.2 kg/m 3 (0.01493 - 0.010) kg water/kg air) or 1.0 1pm (59.2 kg/hr ⁇ 1 1/kg ⁇ lhr / 60 min).
• this system is running in a location where the water has a mildly high hardness and a maximum Cycles of Concentration of 3 should be used.
• an additional 1/3 or 33% bleed should be designed into the system in order to control the mineral content in the recirculated water.
• the system will need a total make-up flow of 1.33 1pm.
• the media is being operated at a typical face velocity of 2.5 m/s and has dimensions of 1.1 m in height and 0.75 m in width.
• the top area of the media is 0.15 m 2 .
• the minimum amount of water to be applied to the top of the media to insure good water distribution and prevent mineral deposits is 3.9 1pm (0.15 m 2 ⁇ 25.8 lpm/m 2 ).
• the 1.33 1pm make-up water at 50 psi acts as motive flow to drive additional recirculated flow through the supply line 212 using eductor 230.
• the Penberthy document teaches a roughly 2: 1 ratio of entrained fluid to motive fluid if acting against a total lift of 10'.
• the evaporation rate will change based on the air entering conditions. When the evaporation rate is less, if the incoming motive flow is left the same there will be excess flow that will go to drain. The mineral content in the sump will decrease to a lower level, the CoC will be reduced, and water will be wasted. In these cases the incoming flow can be reduced to prevent the excess bleed. If the flow were reduced by reducing its pressure, the ratio of supply water to motive water would be reduced. This has the negative effect of reducing the top water flow to below the desired minimum flow for good distribution and scale prevention. In order to reduce the bleed flow, the motive flow is intermittently interrupted, or pulsed, to reduce the excess bleed flow.
• an eductor is used to provide the motive force for the recirculation.
• the energy in the incoming water could also be used to power a mechanical pump, such as a diaphragm pump, a piston pump, or a rotary vane pump. These solutions may be less efficient as they will have mechanical losses.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Sustainable Development (AREA)
• Devices For Blowing Cold Air, Devices For Blowing Warm Air, And Means For Preventing Water Condensation In Air Conditioning Units (AREA)
• Other Air-Conditioning Systems (AREA)
• Fuel Cell (AREA)

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• 2016
  • 2016-10-14 WO PCT/US2016/057140 patent/WO2017066636A1/en active Application Filing
  • 2016-10-14 JP JP2018519413A patent/JP2018530733A/ja active Pending
  • 2016-10-14 US US15/294,221 patent/US20170108251A1/en not_active Abandoned
  • 2016-10-14 CN CN201680067122.XA patent/CN108603725A/zh active Pending
  • 2016-10-14 EP EP16856314.6A patent/EP3362758A1/en not_active Withdrawn
  • 2016-10-14 AU AU2016338682A patent/AU2016338682A1/en not_active Abandoned

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