WO2009089618A1 - Cooling system for building air supply - Google Patents

Cooling system for building air supply Download PDF

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Publication number
WO2009089618A1
WO2009089618A1 PCT/CA2009/000033 CA2009000033W WO2009089618A1 WO 2009089618 A1 WO2009089618 A1 WO 2009089618A1 CA 2009000033 W CA2009000033 W CA 2009000033W WO 2009089618 A1 WO2009089618 A1 WO 2009089618A1
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WO
WIPO (PCT)
Prior art keywords
heat exchange
exchange element
cooling
water
cooling tower
Prior art date
Application number
PCT/CA2009/000033
Other languages
French (fr)
Other versions
WO2009089618A4 (en
Inventor
Neil Mccann
Original Assignee
Mcnnnac Energy Services 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 Mcnnnac Energy Services Inc. filed Critical Mcnnnac Energy Services Inc.
Publication of WO2009089618A1 publication Critical patent/WO2009089618A1/en
Publication of WO2009089618A4 publication Critical patent/WO2009089618A4/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F3/00—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems
    • F24F3/06—Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the arrangements for the supply of heat-exchange fluid for the subsequent treatment of primary air in the room units
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F12/00—Use of energy recovery systems in air conditioning, ventilation or screening
    • F24F12/001—Use of energy recovery systems in air conditioning, ventilation or screening with heat-exchange between supplied and exhausted air
    • F24F12/002—Use of energy recovery systems in air conditioning, ventilation or screening with heat-exchange between supplied and exhausted air using an intermediate heat-transfer fluid
    • 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
    • F28D20/00—Heat storage plants or apparatus in general; Regenerative heat-exchange apparatus not covered by groups F28D17/00 or F28D19/00
    • F28D20/0034—Heat storage plants or apparatus in general; Regenerative heat-exchange apparatus not covered by groups F28D17/00 or F28D19/00 using liquid heat storage material
    • F28D20/0039—Heat storage plants or apparatus in general; Regenerative heat-exchange apparatus not covered by groups F28D17/00 or F28D19/00 using liquid heat storage material with stratification of the heat storage material
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F27/00—Control arrangements or safety devices specially adapted for heat-exchange or heat-transfer apparatus
    • F28F27/003—Control arrangements or safety devices specially adapted for heat-exchange or heat-transfer apparatus specially adapted for cooling towers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F12/00—Use of energy recovery systems in air conditioning, ventilation or screening
    • F24F12/001—Use of energy recovery systems in air conditioning, ventilation or screening with heat-exchange between supplied and exhausted air
    • F24F2012/007—Use of energy recovery systems in air conditioning, ventilation or screening with heat-exchange between supplied and exhausted air using a by-pass for bypassing the heat-exchanger
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F12/00—Use of energy recovery systems in air conditioning, ventilation or screening
    • F24F12/001—Use of energy recovery systems in air conditioning, ventilation or screening with heat-exchange between supplied and exhausted air
    • F24F2012/008—Use of energy recovery systems in air conditioning, ventilation or screening with heat-exchange between supplied and exhausted air cyclic routing supply and exhaust air
    • 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]
    • Y02B30/56—Heat recovery units
    • 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
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/14—Thermal energy storage

Definitions

  • the present invention relates to a system and method for cooling air, and in particular to a system and method for cooling an air supply to a building.
  • chiller units are commonly used to cool the air supply to a building.
  • a compression type conventional chiller vaporized refrigerant is compressed in a compressor which causes the refrigerant to heat up.
  • the hot gas is directed to the condenser where the refrigerant is cooled and condenses.
  • the condenser is cooled by water or air.
  • Many such chiller systems utilize cooling towers to provide a supply of cooled water to the condenser to absorb rejected heat.
  • the liquid refrigerant from the condenser passes through an expansion valve into the evaporator. As the fluid passes through the expansion valve, the pressure of the refrigerant is reduced causing vaporization of the liquid, which results in a large reduction in temperature.
  • the cold refrigerant in an evaporator is used to cool a separate circulatory water system (or any other suitable fluid).
  • the water cooled by the chiller is then pumped to a heat exchanger that is positioned in the flow of the air supply to be cooled.
  • the air passing over the heat exchanger is cooled and is then directed to the various spaces within the building that require cooling.
  • the warmed water exiting the heat exchanger is redirected to the chiller to be cooled again.
  • Conventional chiller units can quickly cool the interior of a structure, but they consume large quantities of electricity, particularly when ambient temperature and humidity are high.
  • a widely used gas absorption refrigerator system cools by evaporating liquid ammonia in a hydrogen environment. The gaseous ammonia is then dissolved into water, and then later separated from the water using a source of heat. This drives off the dissolved ammonia gas which is then condensed into a liquid. The liquid ammonia then enters the hydrogen-charged evaporator to repeat the cycle.
  • Other types of systems are also used.
  • DX Direct Expansion
  • a DX system operates in the same manner as a chiller with the exception that the evaporator is used to cool an air stream directly (there is no chilled water loop).
  • the condenser of a DX system is also typically air cooled.
  • DX systems can quickly cool the interior of a structure, but they consume large quantities of electricity, particularly when ambient temperature and humidity are high.
  • Evaporative coolers are used as an alternative to conventional chillers or DX systems to cool the air supply to residential and commercial buildings in areas of the world having suitable climatic conditions.
  • the use of evaporative coolers is a desirable method of cooling air because of their relatively low installation cost, their relatively lower maintenance costs, and their relatively low cost of operation in comparison with conventional chiller units and DX systems.
  • evaporative coolers use the latent heat of evaporation to cool process water, such evaporative systems do have some operational limitations and disadvantages.
  • the cooling effectiveness of an evaporative cooler is dependent on the ambient wet bulb temperature and is greatly reduced as the temperature or humidity, or both, of the ambient air increases.
  • Evaporative cooling units are usually not able to cool a fluid to a temperature less than the wet bulb temperature of the ambient air.
  • the present invention is directed to a system and method for cooling air and in particular, to a system and method for cooling an air supply to a residential or commercial building.
  • the present invention comprises an interconnected system for cooling the air supply to a building, the system having:
  • cooling tower at least one cooling tower; and (e) storage means selected from at least one stratified storage tank or at least two storage tanks; wherein the cooling tower may be operated at night to produce cooled water that is stored in at least one of the storage tanks for subsequent use in the day.
  • the system is interconnected by conduits having valve means for selectively diverting the flow of water between components of the system.
  • the storage means comprises at least one stratified storage tank, hi one embodiment, the storage means comprises at least two storage tanks, one storage tank being used for storing cooled water and one storage tank being used for storing warmed water.
  • the means for selectively forcing the air supply over the first heat exchange element comprises a duct, at least one bypass louver and a fan.
  • the system also has a second heat exchange element in series with the first heat exchange element, the second heat exchange element being interconnected to the system by conduits having valve means.
  • the system has means for activating and deactivating all, or any of, the cooling tower, the pump means and the valve means, hi one embodiment, the activation and deactivation means is automated and is responsive to any one, or any combination of, the following:
  • the heat exchange element comprises finned cooling coils
  • the system also has an additional heat exchange element proximate to the first heat exchange element, the additional heat exchange element being connected to a conventional chiller, hi another embodiment, there is an additional heat exchange element proximate to the first heat exchange element, the additional heat exchange element comprising the evaporator of a DX system.
  • cooling tower may be operated at night to produce cooled water that is stored in the at least one storage tank for subsequent use in the day.
  • it comprises a method of cooling the air supply to a building, the method comprising:
  • the heat exchange element comprises chilled slab, hi one embodiment, the heat exchange element comprises a chilled ceiling panel, hi one embodiment, the heat exchange element comprises a chilled beam.
  • Figure 1 is a diagrammatic depiction of a prior art system.
  • Figure 2 A is a diagrammatic depiction of one embodiment of the present invention having one heat exchange element and one storage tank.
  • Figure 2B is a diagrammatic depiction of one embodiment of the present invention having one heat exchange element and two storage tanks.
  • Figure 3 A is a diagrammatic depiction of one embodiment of the present invention having one heat exchange element and one storage tank.
  • Figure 3B is a diagrammatic depiction of one embodiment of the present invention having one heat exchange element and two storage tanks.
  • Figure 4 is a diagrammatic depiction of one embodiment of the present invention being used in conjunction with a DX system or a conventional chiller.
  • Figure 5 is a diagrammatic depiction of one embodiment of the present invention having two heat exchange elements and two storage tanks.
  • Figure 6A is a diagrammatic depiction of one embodiment of the present invention having two heat exchange elements and one storage tank.
  • Figure 6B is a diagrammatic depiction of one embodiment of the present invention having two heat exchange elements and two storage tanks.
  • Figure 7 is a diagrammatic depiction of a cross flow cooling tower.
  • Figure 8 is a diagrammatic depiction of a counter flow cooling tower.
  • FIG. 9 is a diagrammatic depiction of one embodiment of the present invention in which the heat exchange element comprises a chilled beam.
  • Figures 1OA and 1OB are diagrammatic depictions of embodiments of the present invention having two cooling towers.
  • Figures HA and HB are diagrammatic depictions of embodiments of the present invention having two cooling towers.
  • Figures 12A and 12B are diagrammatic depictions of embodiments of the present invention having three cooling towers.
  • Figures 13 A and 13B are diagrammatic depictions of embodiments of the present invention having three cooling towers.
  • Figure 14 is a diagrammatic depictions of an embodiment of the present invention having two cooling towers.
  • Figures 15A and 15B are diagrammatic depictions of embodiments of the present invention having two cooling towers.
  • Figure 16 is a diagrammatic depiction of one embodiment of the present invention having three cooling towers.
  • FIGS. 17A and 17B are diagrammatic depictions of embodiments of the present invention having three cooling towers. Detailed Description of Preferred Embodiments
  • the present invention provides for a system and method for cooling air and in particular to a system and method for cooling an air supply to a residential or commercial building.
  • all terms not defined herein have their common art- recognized meanings.
  • the following description is of a specific embodiment or a particular use of the invention, it is intended to be illustrative only, and not limiting of the claimed invention.
  • the following description is intended to cover all alternatives, modifications and equivalents that are included in the spirit and scope of the invention, as defined in the appended claims.
  • the following words are intended to have the following meaning:
  • Building shall mean any structure, commercial or residential in nature, forming an open, partially enclosed, or enclosed space constructed by a planned process of combining materials and components to meet specific conditions of use.
  • Conventional chiller means any chiller unit commonly used with HVAC systems implementing vapor compression of a refrigerant (typically having a compressor, a condenser and an evaporator) or implementing an absorptive refrigeration system.
  • Cooling tower means a tower or other structure that incorporates an evaporative cooler, an evaporative cooler being a cooler that lowers the temperature of a water stream by exposing the water to unsaturated air, promoting evaporation. Evaporation consumes energy from the water stream, reducing the temperature of the water. This cooled water can be used directly (open circuit) or passed over an internal heat exchanger to cool a separate fluid stream (closed circuit).
  • the term cooling tower as used herein is intended to include both cross flow and counter flow type cooling towers. In a cross flow design, the air flow is directed substantially perpendicular to the water flow. In contrast, in a counter flow design, the air flow is substantially opposite of the water flow.
  • the term cooling tower as used herein also encompasses cooling towers having air flow generated by natural draft and mechanical draft including without limitation, induced draft, forced draft and fan assisted natural draft.
  • DX system means an air conditioning unit typically used in residential and smaller commercial buildings implementing vapor compression of a refrigerant, typically having a compressor, a condenser and an evaporator in direct contact with the air supply that requires cooling.
  • Weight bulb temperature means the temperature measured by a thermometer whose bulb is covered by a muslin sleeve which is kept moist with distilled and clean water, freely exposed to the air and free from radiation. At relative humidities below 100%, water evaporates from the bulb which cools the bulb below ambient temperature. To determine relative humidity, ambient temperature is measured using an ordinary thermometer, known as a dry-bulb thermometer.
  • the wet bulb is colder.
  • the precise relative humidity is determined by finding one's wet-bulb and dry-bulb temperatures on a psychrometric chart.
  • the wet bulb temperature is dependant on the dry bulb temperature and the relative humidity. A decrease in dry bulb temperature (with the humidity ratio constant) will also decrease the wet bulb temperature, but not by the same magnitude.
  • FIG. 1 depicts a prior art evaporative cooling system (11).
  • the system (11) is comprised of a cooling tower (12) connected to heat exchange element (14).
  • the purpose of the cooling tower (12) is to provide a source of cooled water to the heat exchange element (14).
  • a pump (18) moves water through the system.
  • the heat exchange element (14) is disposed in the flow of the primary air supply (16).
  • a fan (20) draws the air supply.
  • the cooling tower (12) and pump (18) are inoperative. If the need for cooling arises, the cooling tower (12) is activated and cooled water is circulated through the evaporative cooling system (11) to the heat exchange element (14) and then back to the cooling tower (12).
  • the air-flow (16) passes over the heat exchange element (14) and is cooled. If the cooling tower (12) and associated heat exchange element (14) cannot cool the air sufficiently, then a conventional chiller or DX system (13) having heat exchange element (15) may be activated to cool the air supply (16) provided that as cooling requirements are reduced, the conventional chiller or DX system, as the case may be, can be deactivated. On days where the wet bulb temperature exceeds a desired level, the efficiency of the cooling tower (12) may be so impaired that the conventional chiller or DX system is run alone to cool the primary air supply. These prior art evaporative cooling systems are limited to the capability of the cooling tower (12) to supply cool water to the heat exchange element (14).
  • the ambient temperature usually decreases and the wet bulb temperature correspondingly lowers. Accordingly, a cooling tower being operated at night will be able to cool water more effectively compared to a cooling tower being operated during the warmer day light hours.
  • peak cooling demands typically occur during the day when the ambient temperatures reach the highest level.
  • the system (10) and method of the present invention utilizes the beneficial ability of night time cooling by storing the cooled water for subsequent use during the daylight hours. As such, the system and method of the present invention (10) is able to provide a more steady supply of cold water to the heat exchange element, even on more humid days.
  • the conventional chiller is required less and a reduction in electricity to cool the air supply is possible.
  • the embodiments generally include a single, stratified storage tank or at least two storage tanks; at least one heat exchange element; and at least one cooling tower as described herein.
  • FIGS 2 A and 2B generally show basic components of the cooling system (10) of the present invention.
  • the system (10) has a cooling tower (12) and pump means for circulating fluid (18) which may comprise one or more suitable pumps as may be selected by one skilled in the art including, without limitation, centrifugal pumps, hi a preferred embodiment there are at least two pumps in the system.
  • the system (10) has a first heat exchange element (14) positioned in the air supply flow (16).
  • the first heat exchange element (14) of the system (10) and all heat exchange elements described herein, may comprise any suitable heat exchanger that may be constructed from any suitable metals including, without limitation, copper and aluminum.
  • the air supply (16) to be cooled by the system (10) may be entirely external fresh air, entirely return or exhaust air, or of a mixture of both.
  • the means for forcing the air supply (16) over the first heat exchange element (14) is a combination of a fan (20), a duct (21) and at least one bypass louver (17).
  • the fan (20) has modulated speeds to accommodate varying cooling requirements and to vary the force of the flow of the air supply.
  • the bypass louver (17) may be opened and shut to divert air the air supply (16) across the first heat exchange element (14) within the duct (21).
  • the system has either a single, stratified storage tank or at least two storage tanks for the storage of cooled and warmed water.
  • the storage means comprises a single storage tank (31) employing stratified storage means as are commonly employed by those skilled in the art.
  • at least two storage tanks (28, 30) are used to synchronously store cooled water and heated water.
  • the valve means (26) permits one tank to receive and store cooled water at night and to then provide cooled water to the heat exchange element (14) during the day.
  • the other tank receives warmed water from the heat exchange element (14), stores the warmed water and feeds warmed water to the cooling tower (12) for cooling at night.
  • conduits (19) which may constructed from any suitable piping as is employed in the art.
  • Suitable piping includes, without limitation, plastic piping, galvanized metal piping, and stainless steel piping.
  • the gauge and thickness of the piping will vary depending on the pressure requirements and load capacity of the particular system.
  • the conduits have associated valve means (26) which may be opened and closed to divert the flow of the water between the interconnected components of the system (10) as will described in more detail below.
  • the valve means may comprise any suitable valve employed by those skilled in the art to permit, or prevent, the flow of fluid through a conduit. Examples of suitable valves include, but are not limited to gate valves, butterfly valves and ball valves.
  • warmed water from either the single, stratified storage tank or the storage tank holding warmed water is directed to the cooling tower (12) through the conduits using one of the pumps (18) and by opening and closing the appropriate valves (26).
  • the cooling tower (12) is activated and it cools the incoming water by evaporative cooling. Water cooled by the cooling tower (12) gathers in a reservoir at the base of the cooling tower (12) and is then diverted to either the single, stratified storage tank (31) or one of the storage tanks (28, 30) through the conduits using one of the pumps (18) and by opening and closing the appropriate valves (26).
  • the cooled water is stored for subsequent use during the daytime or night time hours.
  • cooled water from either the single, stratified storage tank or the storage tank receiving and holding the cooled water is directed to the heat exchange element (14) through the conduits (19) using one of the pumps (18) and by opening and closing the appropriate valves (26).
  • Bypass louver (17) is closed and the air supply (16) is cooled.
  • Warmed water from the first heat exchange element (14) is diverted to either the single, stratified storage tank or the storage tank being used to hold warmed water by opening and closing the appropriate valves (26) in the conduits (19).
  • the warmed water is stored until night at which time the appropriate valves are opened allowing the warmed water to flow to the cooling tower (12) through the conduits (19) for cooling in the manner described above. It can be understood that if daytime conditions are suitable, the cooling tower (12) may be operated during the daytime to create cooled water for storage and subsequent use.
  • the single, stratified storage tank or the storage tanks are not the only source of cooled water for the heat exchange element (14) ( Figures 3 A and 3B).
  • the conduits (19) and valves (26) may be configured such that by closing the appropriate valves, the cooling tower (12) and the first heat exchange element (14) form a continuous loop. With the creation of such a loop, the cooling tower (12) feeds cooled water directly to the heat exchange element (14), bypassing either the single, stratified storage tank or the storage tanks (28, 30), with the heat exchange element (14) feeding warmed water directly back to the cooling tower (12) through the conduits (19).
  • Operation in this manner permits flexibility to reserve the use of previously cooled water being held in the storage tank until such time as the cooling tower (12) is unable to provide a sufficient supply of cooled water to the heat exchange element (14).
  • water can be cooled at night using the cooling tower (12) and can be stored in a storage tank.
  • the valves are coordinated such that the cooling tower can be run alone to provide cooled water directly to the heat exchange element (14), provided that when the cooling tower (12) can no longer meet load requirements, the cooling tower (12) would be deactivated and the cooled water from the storage tank would be used to supply the heat exchange element by opening and closing the appropriate valves.
  • the warmed water is returned to either the single, stratified storage tank (31) or the other storage tank (28 or 30) to be held until nightfall when the cooling cycle can start over again.
  • FIG. 4 depicts a conventional chiller (13) having a heat exchange element (15) disposed in the duct (21) adjacent to the first heat exchange element (14).
  • I l exchange element (15) may be opened and closed as required to divert air flow across the heat exchange element (15).
  • An associated DX system or conventional chiller would preferably only be activated and used when the system (10) is unable to sufficiently cool the air supply (16).
  • a system may be employed to cool air such that there is more than one heat exchange element positioned in the air-flow (16).
  • Figure 5 shows a second heat exchange element (33) adjacent to a first heat exchange element (14).
  • the cooling tower (12) feeds cooled water to the storage tanks (28, 30) which in turn supply cooled water to the heat exchange elements (14, 33) as required.
  • the heat exchange elements may be employed selectively and sequentially to meet varying cooling demands and in response to varying ambient conditions.
  • FIGs 6A and 6B depict embodiments wherein the valves (26) of the system may be coordinated such that by closing the appropriate valves, the cooling tower (12) and the first heat exchange element (14) form a continuous loop. The advantages of such a configuration having been previously discussed.
  • the system of the present invention may also be used in an embodiment wherein rather then being disposed in the incoming air supply, the heat exchange element is disposed within the interior of the building, hi such systems the heat exchange element may comprise any suitable type that would be utilized by one skilled in the art for cooling, including but not limited to, a radiator, a chilled slab, a chilled ceiling panel or a chilled beam.
  • These types of heat exchangers cool the interior of the building by a combination of conductive, convective and radiant cooling. They can be passive in nature not employing any type of fan or draft system, or active incorporating fans or draft systems to actively draw in and move air across the surface of the heat exchange element.
  • the system may be connected to one such heat exchange element, or to a plurality disposed at varying locales within the building.
  • Figure 9 shows a diagrammatic depiction of a system of the present invention connected to a passive chilled beam (60) positioned on the ceiling (64) of a room within the interior of a building (62).
  • the cooling towers (12) used in the system described herein can be any suitable cooling tower as would be selected by one skilled in the art. It has been determined that the Baltimore Air Coil Series 3000 (VSD) 3473A-KM/Q with a 10 horse power fan is suitable, such suggestion not intended to be limiting of the invention claimed herein. Both cross-flow type cooling towers and counter-flow type cooling towers may be used with the systems of the present invention.
  • VSD Baltimore Air Coil Series 3000
  • FIG. 7 depicts a cross-flow cooling tower (12).
  • Cross-flow is a design in which the air flow (AF) is directed perpendicular to the water flow (WF). Air flow (AF) enters one or more vertical faces of the cooling tower (12) to meet the fill material (82). Water flows (perpendicular to the air) through the fill material (82) by gravity. The air passes through the fill material (82) and thus past the water flow (WF) into an open plenum area.
  • a distribution or hot water basin (84) consisting of a deep pan with holes or nozzles (not shown) in the bottom is utilized in a cross-flow tower. Gravity distributes the water through the nozzles uniformly across the fill material (82).
  • Figure 8 depicts a counter-flow cooling tower (12). In a counter-flow design the air flow
  • AF is substantially opposite of the water flow (WF).
  • the air flow (AF) first enters an open area beneath the fill media (92) and is then drawn up vertically.
  • the water is sprayed through pressurized nozzles (94) and flows downward through the fill (92), opposite to the air flow
  • both cross-flow and counter- flow cooling towers the interaction of the air and water flow allow a partial equalization and evaporation of water and the air supply, now saturated with water vapor (DA), is discharged from the cooling tower. Further, in each type of cooling tower a sump or cold water basin (86) is used to contain the cooled water after its interaction with the air flow. Both cross-flow and counter-flow designs can be used in natural draft and mechanical draft, and hybrid draft cooling towers.
  • the evaporative cooling systems will be connected to a water source to replenish the volume of water lost through evaporation in the cooling tower.
  • the water source may include without limitation, treated water or rain water, or a mixture of both.
  • some form of water treatment system and filtration system will be employed with the evaporative cooling systems to maintain the water quality and to minimize corrosive damage.
  • the water in the system may also be treated with various suitable chemicals and compounds to enhance its evaporative qualities.
  • the cooling systems described herein, including the individual components of each such system such as pumps, cooling towers and valves may be controlled by automated activation and deactivation means that is responsive to cooling demands and system output and to ambient temperatures.
  • activation and deactivation means may be controlled by a central computer processor that is adapted to receive and interpret sensory data regarding system output, cooling demands and ambient conditions.
  • the sensory system may also be programmed to monitor the volume and temperature of the water in the storage tanks, and to input and process data regarding the same.
  • WO 2008/138112 Al may be used in conjunction with the systems of the present invention.
  • WO 2008/138112 Al describes a cooling system comprising primary and secondary evaporative cooling towers.
  • the second cooling tower is used to provide cooled fluid to a heat exchange element over which the pre-cooled air stream to the primary cooling tower is passed.
  • the pre-cooled air stream delivery to the primary cooling tower results in an ability to cool water to a temperature below wet bulb temperatures.
  • Additional multiple cooling towers may be included to cool the air supply to adjacent cooling towers to meet increased cooling demands.
  • the cooling tower is used exclusively to cool the single, stratified storage tank.
  • cooling begins by opening the three-way valve Vl to allow flow from pump P2 to the cooling tower.
  • Valve V2 is opened to allow flow from pump Pl to the tank.
  • Pumps Pl, P2 and the tower fan are started.
  • the system runs until all tank content has passed through the cooling tower once during "optimal" low wet bulb temperature hours.
  • pumps Pl, P2 and the tower fan are stopped, with the tank cooled.
  • the fans 20a, 20b are started. If cooling is not required, bypass Bl is opened to allow air to bypass the coil. If cooling is required, bypass Bl is closed, allowing air to flow through the heat exchange element HEl .
  • Tank operation begins by opening valve Vl to HEl .
  • Valve V2 is opened to the tank, and pump P2 is started.
  • tank cooling begins at night by opening the three-way valve Vl to allow flow from pump Pl to valve V2 which is opened to the tank.
  • Valve V3 is opened to allow flow from the tank to the cooling tower.
  • Pumps Pl, P2 and the tower fan are started. The system runs until all tank content has passed through the cooling tower once during "optimal" low wet bulb temperature hours. At the end of the cooling period, pumps Pl, P2 and the tower fan are stopped, with the tank cooled.
  • fans 20a, 20b are started. If cooling is not required, bypass Bl is opened to allow air to bypass the coil. If cooling is required, bypass Bl is closed so that air flows through heat exchange element HEl.
  • valve Vl is open to heat exchange element HEl, with check valve C2 preventing errant flow to valve V3.
  • Valve V4 is opened to the cooling tower. The pump Pl and the tower fan are started. When the cooling tower cannot handle the load, pump Pl and the tower fan are stopped.
  • Tank operation begins by opening valve V3 to heat exchange element HEl, with check valve Cl preventing errant flow to valve Vl. Valves V4, V2 are opened to the tank and pump P2 is started.
  • valve Vl is opened to allow flow from the cooling tower to valve V2.
  • Valve V2 is opened to the tank and valve V3 is opened to the cooling tower from the tank.
  • Pumps Pl, P2 are started and the system runs until all tank content has been cooled. During the day, fans 20a, 20b are started. If cooling is not required, bypasses Bl, B2 are opened. If cooling is required, bypass B2 is opened, and valve Vl is opened to allow flow from pump Pl to heat exchange element HEl . If the single stage coil cannot handle the load, bypass B2 is closed, valve V3 is opened to allow flow from pump P2 to heat exchange element HE2, and valve V2 is opened to allow flow from heat exchange element HE2 to the tank.
  • the cooling tower is used exclusively to cool the single, stratified storage tank. Cooling begins at night by opening the three-way valve Vl to allow flow from pump P2 to the first cooling tower (12a). Valve V2 is opened to allow flow from pump Pl to the tank. Pumps Pl, P2 and first tower fan 12a are started. If conditions are favorable, the second cooling tower (12b) and pump P3 are started to precool the first cooling tower (12a). The system runs until the entire tank content has passed through the cooling tower once during "optimal" low wet bulb temperature hours. At the end of the cooling period, pumps Pl, P2 and first tower fan 12a are stopped (and second tower fan 12b and pump P3 if running), with the tank cooled.
  • fans 20a, 20b are started. If cooling is not required, bypass Bl is opened to allow air to bypass the coil. If cooling is required, bypass Bl is closed, allowing air to flow through heat exchange element HEl.
  • Tank operation begins by opening valve Vl to HEl . Valve V2 is opened to the tank, and pump P2 is started.
  • tank cooling begins at night by opening the three-way valve Vl to allow flow from pump Pl to valve V2 which is opened to the tank.
  • Valve V3 is opened to allow flow from the tank to the first cooling tower 12a.
  • Valve V5 is opened to allow flow from pump P2 to the first cooling tower 12a.
  • Pumps Pl, P2 and first tower fan 12a are started.
  • Pump P3 and second tower fan 12b may be started to precool the first cooling tower 12a if ambient conditions are favorable.
  • the system runs until the entire tank content has passed through the cooling tower once during "optimal" low wet bulb temperature hours. At the end of the cooling period, pumps Pl, P2 and the first tower fan 12a are stopped, with the tank cooled.
  • fans 20a, 20b are started. If cooling is not required, bypass Bl is opened to allow air to bypass the coil. If cooling is required, bypass Bl is closed so that air flows through the heat exchange element HEl. If ambient conditions are such that the cooling tower can handle the cooling load, then valve Vl is open to heat exchange element HEl, with check valve C2 preventing errant flow to valve V3. Valve V4 is opened to the first cooling tower 12a. Valve V5 is opened to allow flow from heat exchange element HEl to the first cooling tower 12a. Pump Pl and the first tower fan 12a are started. If the first cooling tower 12a alone cannot handle the load, pump P3 and the second tower fan 12b may be started to precool the first cooling tower 12a if ambient conditions are favorable.
  • Tank operation begins by opening valve V3 to heat exchange element HEl, with check valve Cl preventing errant flow to valve Vl . Valves V4, V2 are opened to the tank and pump P2 is started.
  • the cooling tower is used exclusively to cool the single, stratified storage tank.
  • Tank cooling begins at night by opening the three-way valve Vl to allow flow from pump P2 to the first cooling tower 12a. Valve V2 is opened to allow flow from pump Pl to the tank.
  • Pumps Pl, P2 and first tower fan 12a are started. If conditions are favorable, the second cooling tower fan 12b and pump P3 are started to precool the first cooling tower 12a. If conditions are favorable, the third cooling tower 12c and pump P4 are started to precool the second cooling tower 12b. The system runs until the entire tank content has passed through the cooling tower once during "optimal" low wet bulb temperature hours.
  • pumps Pl, P2 and the first tower fan 12a are stopped, with the tank cooled.
  • fans 20a, 20b are started. If cooling is not required, bypass Bl is opened to allow air to bypass the coil. If cooling is required, bypass Bl is closed so that air flows through heat exchange element HEl .
  • Tank operation begins by opening valve Vl to heat exchange element HEl . Valve V2 is opened to the tank and pump P2 is started.
  • tank cooling begins at night by opening the three-way valve Vl to allow flow from pump Pl to valve V2 which is opened to the tank.
  • Valve V3 is opened to allow flow from the tank to the first cooling tower 12a.
  • Valve V5 is opened to allow flow from pump P2 to the first cooling tower 12a.
  • Pumps Pl, P2 and first tower fan 12a are started. If conditions are favorable, the second cooling tower fan 12b and pump P3 (and the third cooling tower fan 12c and pump P4) may be started to precool the first and second cooling towers 12a, 12b. The system runs until the entire tank content has passed through the cooling tower once during "optimal" low wet bulb temperature hours.
  • pumps Pl, P2 and the first tower fan 12a are stopped, with the tank cooled.
  • fans 20a, 20b are started. If cooling is not required, bypass Bl is opened to allow air to bypass the coil. If cooling is required, bypass Bl is closed so that air flows through heat exchange element HEl. If ambient conditions are such that the first cooling tower 12a can handle the cooling load, then valve Vl is opened to heat exchange element HEl, with check valve C2 preventing errant flow to valve V3.
  • Valve V4 is opened to the first cooling tower 12a.
  • Valve V5 is opened to allow flow from heat exchange element HEl to the first cooling tower 12a. Pump Pl and the first cooling tower fan 12a are started.
  • pump P3 and the second cooling tower 12b may be started to precool the first cooling tower 12a if ambient conditions are favorable. If conditions are unfavorable, pump Pl and the first cooling tower fan 12a are stopped. If conditions are favorable, pump P3 and the second cooling tower fan 12b are started. When the second cooling tower 12b can no longer support the cooling load, pump P4 and the third cooling tower fan 12c are started to precool the second cooling tower 12b. When the cooling towers cannot handle the cooling load, all components are stopped.
  • Tank operation begins by opening valve V3 to heat exchange element HEl, with check valve Cl preventing errant flow to valve Vl . Valves V4, V2 are opened to the tank and pump P2 is started.
  • tank cooling begins at night by opening the three-way valve Vl to allow flow from the first cooling tower 12a to valve V2 which is opened to the tank.
  • Valve V3 is opened to allow flow from the tank to the first cooling tower 12a.
  • Pumps Pl, P2 and first tower fan 12a are started. The system runs until the entire tank content has been cooled.
  • the second cooling tower 12b and pump P3 may be started to precool the first cooling tower 12a.
  • fans 20a, 20b are started. If cooling is not required, bypasses Bl, B2 are opened to allow air to bypass the coil. If cooling is required, bypass B2 is opened, valve Vl is opened to allow flow from pump Pl to heat exchange element HEl.
  • pump P3 and the second cooling tower fan 12b may be started to precool the first cooling tower 12a.
  • Bypass B2 is closed, valve V3 is opened to allow flow from pump P2 to heat exchange element HE2, and valve V2 is opened to allow flow from heat exchange element HE2 to the tank.
  • tank cooling begins at night by opening the three-way valve Vl to allow flow from the first cooling tower 12a to valve V2 which is opened to the tank.
  • Valve V3 is opened to allow flow from the tank to the first cooling tower 12a.
  • Pumps Pl, P2 are started.
  • the system runs until the entire tank content has been cooled.
  • the first and second cooling tower fans 12a, 12b and pumps P3, P4 may be started to precool the first and second cooling towers 12a, 12b, but the two and three stage towers would likely operate during the day.
  • fans 20a, 20b are started. If cooling is not required, bypasses Bl, B2 are opened to allow air to bypass the coil.
  • bypass B2 is opened, valve Vl is opened to allow flow from pump Pl to heat exchange element HEl. If the first cooling tower 12a alone cannot handle the cooling load, pump P3 and the second cooling tower fan 12b may be started to precool the first cooling tower 12a (the third cooling tower fan 12c and pump P4 may be started to precool the second cooling tower 12b in the event that it is unable to support the load).
  • Bypass B2 is closed, valve V3 is opened to allow flow from pump P2 to heat exchange element HE2, and valve V2 is opened to allow flow from heat exchange element HE2 to the tank.

Abstract

A system and method for cooling an air supply to a building. The system employs at least one stand alone cooling tower connected to either one stratified storage tank or multiple storage tanks. The water can be cooled during the cooler night time hours and stored for subsequent day time use.

Description

NIGHT COOLING SYSTEM Field of the Invention
The present invention relates to a system and method for cooling air, and in particular to a system and method for cooling an air supply to a building.
Background
Conventional chiller units are commonly used to cool the air supply to a building. In a compression type conventional chiller, vaporized refrigerant is compressed in a compressor which causes the refrigerant to heat up. The hot gas is directed to the condenser where the refrigerant is cooled and condenses. Typically the condenser is cooled by water or air. Many such chiller systems utilize cooling towers to provide a supply of cooled water to the condenser to absorb rejected heat. The liquid refrigerant from the condenser passes through an expansion valve into the evaporator. As the fluid passes through the expansion valve, the pressure of the refrigerant is reduced causing vaporization of the liquid, which results in a large reduction in temperature. The cold refrigerant in an evaporator is used to cool a separate circulatory water system (or any other suitable fluid).
The water cooled by the chiller is then pumped to a heat exchanger that is positioned in the flow of the air supply to be cooled. The air passing over the heat exchanger is cooled and is then directed to the various spaces within the building that require cooling. The warmed water exiting the heat exchanger is redirected to the chiller to be cooled again. Conventional chiller units can quickly cool the interior of a structure, but they consume large quantities of electricity, particularly when ambient temperature and humidity are high.
Another type of conventional chiller system commonly used employs an absorptive refrigeration system. This type of system utilizes a heat source to provide the energy needed to drive the cooling system rather than being dependent on electricity to run a compressor as with the chiller system described previously. Absorptive refrigerators are popular in situations where electricity is unreliable, costly, or unavailable, where noise from the compressor is problematic, or where surplus heat is readily available. A widely used gas absorption refrigerator system cools by evaporating liquid ammonia in a hydrogen environment. The gaseous ammonia is then dissolved into water, and then later separated from the water using a source of heat. This drives off the dissolved ammonia gas which is then condensed into a liquid. The liquid ammonia then enters the hydrogen-charged evaporator to repeat the cycle. Other types of systems are also used.
Conventional refrigerant based cooling systems, often referred to as DX (Direct Expansion) systems, are also employed to cool the air supply to buildings. A DX system operates in the same manner as a chiller with the exception that the evaporator is used to cool an air stream directly (there is no chilled water loop). The condenser of a DX system is also typically air cooled. Like conventional chiller units, DX systems can quickly cool the interior of a structure, but they consume large quantities of electricity, particularly when ambient temperature and humidity are high.
Evaporative coolers are used as an alternative to conventional chillers or DX systems to cool the air supply to residential and commercial buildings in areas of the world having suitable climatic conditions. The use of evaporative coolers is a desirable method of cooling air because of their relatively low installation cost, their relatively lower maintenance costs, and their relatively low cost of operation in comparison with conventional chiller units and DX systems. Because evaporative coolers use the latent heat of evaporation to cool process water, such evaporative systems do have some operational limitations and disadvantages. In particular, the cooling effectiveness of an evaporative cooler is dependent on the ambient wet bulb temperature and is greatly reduced as the temperature or humidity, or both, of the ambient air increases. This means that the use of evaporative coolers is limited on days when hot and humid conditions are being experienced, and is impractical in regions experiencing prolonged periods of hot and humid weather. Evaporative cooling units are usually not able to cool a fluid to a temperature less than the wet bulb temperature of the ambient air.
At night time, the ambient air temperature generally drops and thus provides a window of time in which an evaporative cooler may be effectively operated to cool water. Unfortunately, this does not correspond with the peak cooling requirements which typically occur during the middle of the daytime.
What is needed is an evaporative cooling system having storage means that can be operated at night to create cooled water for use in the day. Summary of the Invention
The present invention is directed to a system and method for cooling air and in particular, to a system and method for cooling an air supply to a residential or commercial building.
In one aspect of the present invention, it comprises an interconnected system for cooling the air supply to a building, the system having:
(a) a heat exchange element;
(b) means for forcing the air supply over the heat exchange element;
(c) pump means for circulating water through the system;
(d) at least one cooling tower; and (e) storage means selected from at least one stratified storage tank or at least two storage tanks; wherein the cooling tower may be operated at night to produce cooled water that is stored in at least one of the storage tanks for subsequent use in the day.
Li one embodiment, the system is interconnected by conduits having valve means for selectively diverting the flow of water between components of the system. In one embodiment, the storage means comprises at least one stratified storage tank, hi one embodiment, the storage means comprises at least two storage tanks, one storage tank being used for storing cooled water and one storage tank being used for storing warmed water. In another embodiment, the means for selectively forcing the air supply over the first heat exchange element comprises a duct, at least one bypass louver and a fan. hi one embodiment, the system also has a second heat exchange element in series with the first heat exchange element, the second heat exchange element being interconnected to the system by conduits having valve means.
hi one embodiment, the system has means for activating and deactivating all, or any of, the cooling tower, the pump means and the valve means, hi one embodiment, the activation and deactivation means is automated and is responsive to any one, or any combination of, the following:
(a) changes in cooling requirements; (b) ambient wet bulb temperature; (c) the amount of water contained in either the stratified storage tank or the storage tanks; and
(d) the temperature of the water contained in either the stratified storage tank or the storage tanks.
In one embodiment, the heat exchange element comprises finned cooling coils, hi one embodiment, the system also has an additional heat exchange element proximate to the first heat exchange element, the additional heat exchange element being connected to a conventional chiller, hi another embodiment, there is an additional heat exchange element proximate to the first heat exchange element, the additional heat exchange element comprising the evaporator of a DX system.
In another aspect of the invention, it comprises an interconnected system for cooling the air supply to a building, the system having:
(a) a heat exchange element; (b) means for forcing the air supply over the heat exchange element;
(c) pump means for circulating water through the system;
(d) at least one cooling tower; and
(e) at least one stratified storage tank; wherein the cooling tower may be operated at night to produce cooled water that is stored in the at least one storage tank for subsequent use in the day.
In another aspect of the present invention, it comprises a method of cooling the air supply to a building, the method comprising:
(a) cooling water during the night using at least one cooling tower;
(b) storing the cooled water in storage means selected from at least one stratified storage tank, or one of two storage tanks;
(c) selectively forcing the air supply across a heat exchange element, the heat exchange element being supplied with cooled water from either the stratified storage tank, or the one of two storage tanks; and
(d) storing warmed water being discharged from the heat exchange element in the stratified storage tank, or the second of two storage tanks. In another aspect of the invention, it comprises an interconnected system for cooling the interior of a building, the system comprising:
(a) a heat exchange element disposed within the interior of the building;
(b) pump means for circulating water through the system; (c) at least one cooling tower; and
(d) storage means selected from at least one stratified storage tank or at least two storage tanks; wherein the cooling tower may be operated at night to produce cooled water that is stored in at least one of the storage tanks for subsequent use in the day.
hi one embodiment, the heat exchange element comprises chilled slab, hi one embodiment, the heat exchange element comprises a chilled ceiling panel, hi one embodiment, the heat exchange element comprises a chilled beam.
Brief Description of the Drawings
The invention will now be described by way of an exemplary embodiment with reference to the accompanying simplified, diagrammatic, not-to-scale drawings, hi the drawings:
Figure 1 is a diagrammatic depiction of a prior art system.
Figure 2 A is a diagrammatic depiction of one embodiment of the present invention having one heat exchange element and one storage tank.
Figure 2B is a diagrammatic depiction of one embodiment of the present invention having one heat exchange element and two storage tanks.
Figure 3 A is a diagrammatic depiction of one embodiment of the present invention having one heat exchange element and one storage tank.
Figure 3B is a diagrammatic depiction of one embodiment of the present invention having one heat exchange element and two storage tanks.
Figure 4 is a diagrammatic depiction of one embodiment of the present invention being used in conjunction with a DX system or a conventional chiller. Figure 5 is a diagrammatic depiction of one embodiment of the present invention having two heat exchange elements and two storage tanks.
Figure 6A is a diagrammatic depiction of one embodiment of the present invention having two heat exchange elements and one storage tank.
Figure 6B is a diagrammatic depiction of one embodiment of the present invention having two heat exchange elements and two storage tanks.
Figure 7 is a diagrammatic depiction of a cross flow cooling tower.
Figure 8 is a diagrammatic depiction of a counter flow cooling tower.
Figure 9 is a diagrammatic depiction of one embodiment of the present invention in which the heat exchange element comprises a chilled beam.
Figures 1OA and 1OB are diagrammatic depictions of embodiments of the present invention having two cooling towers.
Figures HA and HB are diagrammatic depictions of embodiments of the present invention having two cooling towers.
Figures 12A and 12B are diagrammatic depictions of embodiments of the present invention having three cooling towers.
Figures 13 A and 13B are diagrammatic depictions of embodiments of the present invention having three cooling towers.
Figure 14 is a diagrammatic depictions of an embodiment of the present invention having two cooling towers.
Figures 15A and 15B are diagrammatic depictions of embodiments of the present invention having two cooling towers.
Figure 16 is a diagrammatic depiction of one embodiment of the present invention having three cooling towers.
Figures 17A and 17B are diagrammatic depictions of embodiments of the present invention having three cooling towers. Detailed Description of Preferred Embodiments
The present invention provides for a system and method for cooling air and in particular to a system and method for cooling an air supply to a residential or commercial building. When describing the present invention, all terms not defined herein have their common art- recognized meanings. To the extent that the following description is of a specific embodiment or a particular use of the invention, it is intended to be illustrative only, and not limiting of the claimed invention. The following description is intended to cover all alternatives, modifications and equivalents that are included in the spirit and scope of the invention, as defined in the appended claims. In this patent the following words are intended to have the following meaning:
"Building" shall mean any structure, commercial or residential in nature, forming an open, partially enclosed, or enclosed space constructed by a planned process of combining materials and components to meet specific conditions of use.
"Conventional chiller" means any chiller unit commonly used with HVAC systems implementing vapor compression of a refrigerant (typically having a compressor, a condenser and an evaporator) or implementing an absorptive refrigeration system.
"Cooling tower" means a tower or other structure that incorporates an evaporative cooler, an evaporative cooler being a cooler that lowers the temperature of a water stream by exposing the water to unsaturated air, promoting evaporation. Evaporation consumes energy from the water stream, reducing the temperature of the water. This cooled water can be used directly (open circuit) or passed over an internal heat exchanger to cool a separate fluid stream (closed circuit). The term cooling tower as used herein is intended to include both cross flow and counter flow type cooling towers. In a cross flow design, the air flow is directed substantially perpendicular to the water flow. In contrast, in a counter flow design, the air flow is substantially opposite of the water flow. The term cooling tower as used herein also encompasses cooling towers having air flow generated by natural draft and mechanical draft including without limitation, induced draft, forced draft and fan assisted natural draft.
"DX system" means an air conditioning unit typically used in residential and smaller commercial buildings implementing vapor compression of a refrigerant, typically having a compressor, a condenser and an evaporator in direct contact with the air supply that requires cooling. "Wet bulb temperature" means the temperature measured by a thermometer whose bulb is covered by a muslin sleeve which is kept moist with distilled and clean water, freely exposed to the air and free from radiation. At relative humidities below 100%, water evaporates from the bulb which cools the bulb below ambient temperature. To determine relative humidity, ambient temperature is measured using an ordinary thermometer, known as a dry-bulb thermometer. At any given ambient temperature, less relative humidity results in a greater difference between the dry-bulb and wet-bulb temperatures; the wet bulb is colder. The precise relative humidity is determined by finding one's wet-bulb and dry-bulb temperatures on a psychrometric chart. The wet bulb temperature is dependant on the dry bulb temperature and the relative humidity. A decrease in dry bulb temperature (with the humidity ratio constant) will also decrease the wet bulb temperature, but not by the same magnitude.
Figure 1 depicts a prior art evaporative cooling system (11). The system (11) is comprised of a cooling tower (12) connected to heat exchange element (14). The purpose of the cooling tower (12) is to provide a source of cooled water to the heat exchange element (14). A pump (18) moves water through the system. The heat exchange element (14) is disposed in the flow of the primary air supply (16). A fan (20) draws the air supply. When conditions in the building and external environment are such that the air supply does not require cooling, the cooling tower (12) and pump (18) are inoperative. If the need for cooling arises, the cooling tower (12) is activated and cooled water is circulated through the evaporative cooling system (11) to the heat exchange element (14) and then back to the cooling tower (12). The air-flow (16) passes over the heat exchange element (14) and is cooled. If the cooling tower (12) and associated heat exchange element (14) cannot cool the air sufficiently, then a conventional chiller or DX system (13) having heat exchange element (15) may be activated to cool the air supply (16) provided that as cooling requirements are reduced, the conventional chiller or DX system, as the case may be, can be deactivated. On days where the wet bulb temperature exceeds a desired level, the efficiency of the cooling tower (12) may be so impaired that the conventional chiller or DX system is run alone to cool the primary air supply. These prior art evaporative cooling systems are limited to the capability of the cooling tower (12) to supply cool water to the heat exchange element (14). On certain days, especially when there is high ambient humidity, the wet bulb temperature rises, greatly reducing the ability of the stand alone cooling tower to supply water cold enough to sufficiently cool the air supply. In such circumstances, the conventional chiller or DX system must be relied upon heavily which is costly due to the consumption of large amounts of energy.
At night, after the sun has gone down, the ambient temperature usually decreases and the wet bulb temperature correspondingly lowers. Accordingly, a cooling tower being operated at night will be able to cool water more effectively compared to a cooling tower being operated during the warmer day light hours. However, peak cooling demands typically occur during the day when the ambient temperatures reach the highest level. The system (10) and method of the present invention utilizes the beneficial ability of night time cooling by storing the cooled water for subsequent use during the daylight hours. As such, the system and method of the present invention (10) is able to provide a more steady supply of cold water to the heat exchange element, even on more humid days. Thus, the conventional chiller is required less and a reduction in electricity to cool the air supply is possible.
Various embodiments of a cooling system (10) of the present invention are shown in the figures, with details of operation provided in the Examples. The embodiments generally include a single, stratified storage tank or at least two storage tanks; at least one heat exchange element; and at least one cooling tower as described herein.
Figures 2 A and 2B generally show basic components of the cooling system (10) of the present invention. The system (10) has a cooling tower (12) and pump means for circulating fluid (18) which may comprise one or more suitable pumps as may be selected by one skilled in the art including, without limitation, centrifugal pumps, hi a preferred embodiment there are at least two pumps in the system. The system (10) has a first heat exchange element (14) positioned in the air supply flow (16). The first heat exchange element (14) of the system (10) and all heat exchange elements described herein, may comprise any suitable heat exchanger that may be constructed from any suitable metals including, without limitation, copper and aluminum. The air supply (16) to be cooled by the system (10) may be entirely external fresh air, entirely return or exhaust air, or of a mixture of both. Such mixtures are achieved using louvers (23) that divert or allow the relevant air flow. The means for forcing the air supply (16) over the first heat exchange element (14) is a combination of a fan (20), a duct (21) and at least one bypass louver (17). hi one embodiment, the fan (20) has modulated speeds to accommodate varying cooling requirements and to vary the force of the flow of the air supply. The bypass louver (17) may be opened and shut to divert air the air supply (16) across the first heat exchange element (14) within the duct (21).
The system has either a single, stratified storage tank or at least two storage tanks for the storage of cooled and warmed water. In the embodiments shown in Figures 2A, 3A, 6A, 10A- 13 A, 15A and 17 A, the storage means comprises a single storage tank (31) employing stratified storage means as are commonly employed by those skilled in the art. In the embodiments shown in Figures 2B, 3B, 4, 5, 6B, 10B-13B, 14, 15B, 16 and 17B, at least two storage tanks (28, 30) are used to synchronously store cooled water and heated water. The valve means (26) permits one tank to receive and store cooled water at night and to then provide cooled water to the heat exchange element (14) during the day. The other tank receives warmed water from the heat exchange element (14), stores the warmed water and feeds warmed water to the cooling tower (12) for cooling at night.
The components of the system (10) are interconnected by conduits (19) which may constructed from any suitable piping as is employed in the art. Suitable piping includes, without limitation, plastic piping, galvanized metal piping, and stainless steel piping. The gauge and thickness of the piping will vary depending on the pressure requirements and load capacity of the particular system. The conduits have associated valve means (26) which may be opened and closed to divert the flow of the water between the interconnected components of the system (10) as will described in more detail below. The valve means may comprise any suitable valve employed by those skilled in the art to permit, or prevent, the flow of fluid through a conduit. Examples of suitable valves include, but are not limited to gate valves, butterfly valves and ball valves.
If conditions are suitable for night cooling, warmed water from either the single, stratified storage tank or the storage tank holding warmed water is directed to the cooling tower (12) through the conduits using one of the pumps (18) and by opening and closing the appropriate valves (26). The cooling tower (12) is activated and it cools the incoming water by evaporative cooling. Water cooled by the cooling tower (12) gathers in a reservoir at the base of the cooling tower (12) and is then diverted to either the single, stratified storage tank (31) or one of the storage tanks (28, 30) through the conduits using one of the pumps (18) and by opening and closing the appropriate valves (26). The cooled water is stored for subsequent use during the daytime or night time hours. If cooling of the air supply (16) is needed during the day, or during the night, cooled water from either the single, stratified storage tank or the storage tank receiving and holding the cooled water is directed to the heat exchange element (14) through the conduits (19) using one of the pumps (18) and by opening and closing the appropriate valves (26). Bypass louver (17) is closed and the air supply (16) is cooled. Warmed water from the first heat exchange element (14) is diverted to either the single, stratified storage tank or the storage tank being used to hold warmed water by opening and closing the appropriate valves (26) in the conduits (19). The warmed water is stored until night at which time the appropriate valves are opened allowing the warmed water to flow to the cooling tower (12) through the conduits (19) for cooling in the manner described above. It can be understood that if daytime conditions are suitable, the cooling tower (12) may be operated during the daytime to create cooled water for storage and subsequent use.
The single, stratified storage tank or the storage tanks are not the only source of cooled water for the heat exchange element (14) (Figures 3 A and 3B). The conduits (19) and valves (26) may be configured such that by closing the appropriate valves, the cooling tower (12) and the first heat exchange element (14) form a continuous loop. With the creation of such a loop, the cooling tower (12) feeds cooled water directly to the heat exchange element (14), bypassing either the single, stratified storage tank or the storage tanks (28, 30), with the heat exchange element (14) feeding warmed water directly back to the cooling tower (12) through the conduits (19). Operation in this manner permits flexibility to reserve the use of previously cooled water being held in the storage tank until such time as the cooling tower (12) is unable to provide a sufficient supply of cooled water to the heat exchange element (14). For example, water can be cooled at night using the cooling tower (12) and can be stored in a storage tank. During the following day, the valves are coordinated such that the cooling tower can be run alone to provide cooled water directly to the heat exchange element (14), provided that when the cooling tower (12) can no longer meet load requirements, the cooling tower (12) would be deactivated and the cooled water from the storage tank would be used to supply the heat exchange element by opening and closing the appropriate valves. The warmed water is returned to either the single, stratified storage tank (31) or the other storage tank (28 or 30) to be held until nightfall when the cooling cycle can start over again.
The systems of the present invention may be used in an assistive manner in conjunction with a conventional chiller or a DX System. Figure 4 depicts a conventional chiller (13) having a heat exchange element (15) disposed in the duct (21) adjacent to the first heat exchange element (14). A bypass louver (17) associated with the conventional chiller heat
I l exchange element (15) may be opened and closed as required to divert air flow across the heat exchange element (15). An associated DX system or conventional chiller would preferably only be activated and used when the system (10) is unable to sufficiently cool the air supply (16). In certain geographical locations where ambient conditions are suitable, it is possible to install a system of the present invention without an associated conventional chiller or DX system. While geographic location of the subject building and the associated ambient conditions greatly influence the cooling capability of the systems of the present invention, it can also be understood that the required amount of cooling of an incoming air supply will also be influenced subjectively by the demands of the occupants of the building that is receiving the air supply.
As shown in Figure 5, a system may be employed to cool air such that there is more than one heat exchange element positioned in the air-flow (16). Figure 5 shows a second heat exchange element (33) adjacent to a first heat exchange element (14). In the system shown in Figure 5, the cooling tower (12) feeds cooled water to the storage tanks (28, 30) which in turn supply cooled water to the heat exchange elements (14, 33) as required. It can be understood that if more than one heat exchange element is employed, the heat exchange elements may be employed selectively and sequentially to meet varying cooling demands and in response to varying ambient conditions. As more heat exchange elements are employed in the flow path of the air (16), it may be necessary to increase fan speed, to utilize a larger fan, or to use more fans to physically force the air through the heat exchange elements. Figures 6A and 6B depict embodiments wherein the valves (26) of the system may be coordinated such that by closing the appropriate valves, the cooling tower (12) and the first heat exchange element (14) form a continuous loop. The advantages of such a configuration having been previously discussed.
The system of the present invention may also be used in an embodiment wherein rather then being disposed in the incoming air supply, the heat exchange element is disposed within the interior of the building, hi such systems the heat exchange element may comprise any suitable type that would be utilized by one skilled in the art for cooling, including but not limited to, a radiator, a chilled slab, a chilled ceiling panel or a chilled beam. These types of heat exchangers cool the interior of the building by a combination of conductive, convective and radiant cooling. They can be passive in nature not employing any type of fan or draft system, or active incorporating fans or draft systems to actively draw in and move air across the surface of the heat exchange element. The system may be connected to one such heat exchange element, or to a plurality disposed at varying locales within the building. Figure 9 shows a diagrammatic depiction of a system of the present invention connected to a passive chilled beam (60) positioned on the ceiling (64) of a room within the interior of a building (62).
The cooling towers (12) used in the system described herein, can be any suitable cooling tower as would be selected by one skilled in the art. It has been determined that the Baltimore Air Coil Series 3000 (VSD) 3473A-KM/Q with a 10 horse power fan is suitable, such suggestion not intended to be limiting of the invention claimed herein. Both cross-flow type cooling towers and counter-flow type cooling towers may be used with the systems of the present invention.
Figure 7 depicts a cross-flow cooling tower (12). Cross-flow is a design in which the air flow (AF) is directed perpendicular to the water flow (WF). Air flow (AF) enters one or more vertical faces of the cooling tower (12) to meet the fill material (82). Water flows (perpendicular to the air) through the fill material (82) by gravity. The air passes through the fill material (82) and thus past the water flow (WF) into an open plenum area. A distribution or hot water basin (84) consisting of a deep pan with holes or nozzles (not shown) in the bottom is utilized in a cross-flow tower. Gravity distributes the water through the nozzles uniformly across the fill material (82).
Figure 8 depicts a counter-flow cooling tower (12). In a counter-flow design the air flow
(AF) is substantially opposite of the water flow (WF). The air flow (AF) first enters an open area beneath the fill media (92) and is then drawn up vertically. The water is sprayed through pressurized nozzles (94) and flows downward through the fill (92), opposite to the air flow
(AF).
In both cross-flow and counter- flow cooling towers the interaction of the air and water flow allow a partial equalization and evaporation of water and the air supply, now saturated with water vapor (DA), is discharged from the cooling tower. Further, in each type of cooling tower a sump or cold water basin (86) is used to contain the cooled water after its interaction with the air flow. Both cross-flow and counter-flow designs can be used in natural draft and mechanical draft, and hybrid draft cooling towers.
It will be understood by one skilled in the art, that in accordance with standard practice, the evaporative cooling systems will be connected to a water source to replenish the volume of water lost through evaporation in the cooling tower. The water source may include without limitation, treated water or rain water, or a mixture of both. It will also be understood by one skilled in the art that some form of water treatment system and filtration system will be employed with the evaporative cooling systems to maintain the water quality and to minimize corrosive damage. The water in the system may also be treated with various suitable chemicals and compounds to enhance its evaporative qualities. The cooling systems described herein, including the individual components of each such system such as pumps, cooling towers and valves may be controlled by automated activation and deactivation means that is responsive to cooling demands and system output and to ambient temperatures. In general terms, any suitable electronic sensory feed-back system may be utilized as would be selected by one skilled in the art. Such activation and deactivation means may be controlled by a central computer processor that is adapted to receive and interpret sensory data regarding system output, cooling demands and ambient conditions. The sensory system may also be programmed to monitor the volume and temperature of the water in the storage tanks, and to input and process data regarding the same.
Multiple cooling towers, such as those described in International Publication No. WO
2008/138112 Al, may be used in conjunction with the systems of the present invention. WO 2008/138112 Al describes a cooling system comprising primary and secondary evaporative cooling towers. The second cooling tower is used to provide cooled fluid to a heat exchange element over which the pre-cooled air stream to the primary cooling tower is passed. The pre-cooled air stream delivery to the primary cooling tower results in an ability to cool water to a temperature below wet bulb temperatures. Additional multiple cooling towers may be included to cool the air supply to adjacent cooling towers to meet increased cooling demands. In one embodiment, there are at least two cooling towers, as shown for example, in Figures 1OB, HB, 14 and 15B. The details of operation of systems of the present invention incorporating two cooling towers are described in Examples 4, 5 and 8 to accompany Figures 1OA, HA and 15 A, respectively. In one embodiment, there are at least three cooling towers, as shown for example, in Figures 12B, 13B, 16 and 17B. The details of operation of systems of the present invention incorporating three cooling towers are described in Examples 6, 7 and 9 to accompany Figures 12 A, 13 A and 17 A, respectively.
While the embodiments described above, are directed to cooling air, it can be understood that the heat exchange elements of the systems described herein may be used to cool any gaseous or liquid substance that needs cooling. Thus, the present invention would have equal application in industrial processes requiring the cooling of a process air supply or requiring the cooling of some process substance.
The Examples provided below are not intended to be limited to these examples alone, but are intended only to illustrate and describe the invention rather than limit the claims that follow.
Example 1
In the system shown in Figure 2A, the cooling tower is used exclusively to cool the single, stratified storage tank. At night, cooling begins by opening the three-way valve Vl to allow flow from pump P2 to the cooling tower. Valve V2 is opened to allow flow from pump Pl to the tank. Pumps Pl, P2 and the tower fan are started. The system runs until all tank content has passed through the cooling tower once during "optimal" low wet bulb temperature hours. At the end of the cooling period, pumps Pl, P2 and the tower fan are stopped, with the tank cooled. During the day, the fans 20a, 20b are started. If cooling is not required, bypass Bl is opened to allow air to bypass the coil. If cooling is required, bypass Bl is closed, allowing air to flow through the heat exchange element HEl . Tank operation begins by opening valve Vl to HEl . Valve V2 is opened to the tank, and pump P2 is started.
Example 2
In the system shown in Figure 3 A, tank cooling begins at night by opening the three-way valve Vl to allow flow from pump Pl to valve V2 which is opened to the tank. Valve V3 is opened to allow flow from the tank to the cooling tower. Pumps Pl, P2 and the tower fan are started. The system runs until all tank content has passed through the cooling tower once during "optimal" low wet bulb temperature hours. At the end of the cooling period, pumps Pl, P2 and the tower fan are stopped, with the tank cooled. During the day, fans 20a, 20b are started. If cooling is not required, bypass Bl is opened to allow air to bypass the coil. If cooling is required, bypass Bl is closed so that air flows through heat exchange element HEl. If ambient conditions are such that the cooling tower can handle the cooling load, then valve Vl is open to heat exchange element HEl, with check valve C2 preventing errant flow to valve V3. Valve V4 is opened to the cooling tower. The pump Pl and the tower fan are started. When the cooling tower cannot handle the load, pump Pl and the tower fan are stopped. Tank operation begins by opening valve V3 to heat exchange element HEl, with check valve Cl preventing errant flow to valve Vl. Valves V4, V2 are opened to the tank and pump P2 is started.
Example 3
In the system shown in Figure 6 A, valve Vl is opened to allow flow from the cooling tower to valve V2. Valve V2 is opened to the tank and valve V3 is opened to the cooling tower from the tank. Pumps Pl, P2 are started and the system runs until all tank content has been cooled. During the day, fans 20a, 20b are started. If cooling is not required, bypasses Bl, B2 are opened. If cooling is required, bypass B2 is opened, and valve Vl is opened to allow flow from pump Pl to heat exchange element HEl . If the single stage coil cannot handle the load, bypass B2 is closed, valve V3 is opened to allow flow from pump P2 to heat exchange element HE2, and valve V2 is opened to allow flow from heat exchange element HE2 to the tank.
Example 4
In the system shown in Figure 1OA, the cooling tower is used exclusively to cool the single, stratified storage tank. Cooling begins at night by opening the three-way valve Vl to allow flow from pump P2 to the first cooling tower (12a). Valve V2 is opened to allow flow from pump Pl to the tank. Pumps Pl, P2 and first tower fan 12a are started. If conditions are favorable, the second cooling tower (12b) and pump P3 are started to precool the first cooling tower (12a). The system runs until the entire tank content has passed through the cooling tower once during "optimal" low wet bulb temperature hours. At the end of the cooling period, pumps Pl, P2 and first tower fan 12a are stopped (and second tower fan 12b and pump P3 if running), with the tank cooled. During the day, fans 20a, 20b are started. If cooling is not required, bypass Bl is opened to allow air to bypass the coil. If cooling is required, bypass Bl is closed, allowing air to flow through heat exchange element HEl. Tank operation begins by opening valve Vl to HEl . Valve V2 is opened to the tank, and pump P2 is started.
Example 5
In the system shown in Figure 1 IA, tank cooling begins at night by opening the three-way valve Vl to allow flow from pump Pl to valve V2 which is opened to the tank. Valve V3 is opened to allow flow from the tank to the first cooling tower 12a. Valve V5 is opened to allow flow from pump P2 to the first cooling tower 12a. Pumps Pl, P2 and first tower fan 12a are started. Pump P3 and second tower fan 12b may be started to precool the first cooling tower 12a if ambient conditions are favorable. The system runs until the entire tank content has passed through the cooling tower once during "optimal" low wet bulb temperature hours. At the end of the cooling period, pumps Pl, P2 and the first tower fan 12a are stopped, with the tank cooled. During the day, fans 20a, 20b are started. If cooling is not required, bypass Bl is opened to allow air to bypass the coil. If cooling is required, bypass Bl is closed so that air flows through the heat exchange element HEl. If ambient conditions are such that the cooling tower can handle the cooling load, then valve Vl is open to heat exchange element HEl, with check valve C2 preventing errant flow to valve V3. Valve V4 is opened to the first cooling tower 12a. Valve V5 is opened to allow flow from heat exchange element HEl to the first cooling tower 12a. Pump Pl and the first tower fan 12a are started. If the first cooling tower 12a alone cannot handle the load, pump P3 and the second tower fan 12b may be started to precool the first cooling tower 12a if ambient conditions are favorable. If conditions are unfavorable, pump Pl and the first tower fan 12a are stopped. If conditions are favorable, pump P3 and the second tower fan 12b are started. When the cooling towers 12a, 12b can no longer handle the cooling load, all components are stopped. Tank operation begins by opening valve V3 to heat exchange element HEl, with check valve Cl preventing errant flow to valve Vl . Valves V4, V2 are opened to the tank and pump P2 is started.
Example 6
hi the system shown in Figure 12 A, the cooling tower is used exclusively to cool the single, stratified storage tank. Tank cooling begins at night by opening the three-way valve Vl to allow flow from pump P2 to the first cooling tower 12a. Valve V2 is opened to allow flow from pump Pl to the tank. Pumps Pl, P2 and first tower fan 12a are started. If conditions are favorable, the second cooling tower fan 12b and pump P3 are started to precool the first cooling tower 12a. If conditions are favorable, the third cooling tower 12c and pump P4 are started to precool the second cooling tower 12b. The system runs until the entire tank content has passed through the cooling tower once during "optimal" low wet bulb temperature hours. At the end of the cooling period, pumps Pl, P2 and the first tower fan 12a (and the second and third cooling tower fans 12b, 12c, and pumps P3, P4 if running) are stopped, with the tank cooled. During the day, fans 20a, 20b are started. If cooling is not required, bypass Bl is opened to allow air to bypass the coil. If cooling is required, bypass Bl is closed so that air flows through heat exchange element HEl . Tank operation begins by opening valve Vl to heat exchange element HEl . Valve V2 is opened to the tank and pump P2 is started.
Example 7
hi the system shown in Figure 13 A, tank cooling begins at night by opening the three-way valve Vl to allow flow from pump Pl to valve V2 which is opened to the tank. Valve V3 is opened to allow flow from the tank to the first cooling tower 12a. Valve V5 is opened to allow flow from pump P2 to the first cooling tower 12a. Pumps Pl, P2 and first tower fan 12a are started. If conditions are favorable, the second cooling tower fan 12b and pump P3 (and the third cooling tower fan 12c and pump P4) may be started to precool the first and second cooling towers 12a, 12b. The system runs until the entire tank content has passed through the cooling tower once during "optimal" low wet bulb temperature hours. At the end of the cooling period, pumps Pl, P2 and the first tower fan 12a are stopped, with the tank cooled. During the day, fans 20a, 20b are started. If cooling is not required, bypass Bl is opened to allow air to bypass the coil. If cooling is required, bypass Bl is closed so that air flows through heat exchange element HEl. If ambient conditions are such that the first cooling tower 12a can handle the cooling load, then valve Vl is opened to heat exchange element HEl, with check valve C2 preventing errant flow to valve V3. Valve V4 is opened to the first cooling tower 12a. Valve V5 is opened to allow flow from heat exchange element HEl to the first cooling tower 12a. Pump Pl and the first cooling tower fan 12a are started. When the first cooling tower 12a alone cannot handle the cooling load, pump P3 and the second cooling tower 12b may be started to precool the first cooling tower 12a if ambient conditions are favorable. If conditions are unfavorable, pump Pl and the first cooling tower fan 12a are stopped. If conditions are favorable, pump P3 and the second cooling tower fan 12b are started. When the second cooling tower 12b can no longer support the cooling load, pump P4 and the third cooling tower fan 12c are started to precool the second cooling tower 12b. When the cooling towers cannot handle the cooling load, all components are stopped. Tank operation begins by opening valve V3 to heat exchange element HEl, with check valve Cl preventing errant flow to valve Vl . Valves V4, V2 are opened to the tank and pump P2 is started. Example 8
In the system shown in Figure 15 A, tank cooling begins at night by opening the three-way valve Vl to allow flow from the first cooling tower 12a to valve V2 which is opened to the tank. Valve V3 is opened to allow flow from the tank to the first cooling tower 12a. Pumps Pl, P2 and first tower fan 12a are started. The system runs until the entire tank content has been cooled. The second cooling tower 12b and pump P3 may be started to precool the first cooling tower 12a. During the day, fans 20a, 20b are started. If cooling is not required, bypasses Bl, B2 are opened to allow air to bypass the coil. If cooling is required, bypass B2 is opened, valve Vl is opened to allow flow from pump Pl to heat exchange element HEl. If the first cooling tower 12a alone cannot handle the cooling load, pump P3 and the second cooling tower fan 12b may be started to precool the first cooling tower 12a. Bypass B2 is closed, valve V3 is opened to allow flow from pump P2 to heat exchange element HE2, and valve V2 is opened to allow flow from heat exchange element HE2 to the tank.
Example 9
In the system shown in Figure 17 A, tank cooling begins at night by opening the three-way valve Vl to allow flow from the first cooling tower 12a to valve V2 which is opened to the tank. Valve V3 is opened to allow flow from the tank to the first cooling tower 12a. Pumps Pl, P2 are started. The system runs until the entire tank content has been cooled. The first and second cooling tower fans 12a, 12b and pumps P3, P4 may be started to precool the first and second cooling towers 12a, 12b, but the two and three stage towers would likely operate during the day. During the day, fans 20a, 20b are started. If cooling is not required, bypasses Bl, B2 are opened to allow air to bypass the coil. If cooling is required, bypass B2 is opened, valve Vl is opened to allow flow from pump Pl to heat exchange element HEl. If the first cooling tower 12a alone cannot handle the cooling load, pump P3 and the second cooling tower fan 12b may be started to precool the first cooling tower 12a (the third cooling tower fan 12c and pump P4 may be started to precool the second cooling tower 12b in the event that it is unable to support the load). Bypass B2 is closed, valve V3 is opened to allow flow from pump P2 to heat exchange element HE2, and valve V2 is opened to allow flow from heat exchange element HE2 to the tank. As will be apparent to those skilled in the art, various modifications, adaptations and variations of the foregoing specific disclosure can be made without departing from the scope of the invention claimed herein.

Claims

WHAT IS CLAIMED IS:
1. An interconnected system for cooling the air supply to a building, the system comprising:
(a) a heat exchange element;
(b) means for forcing the air supply over the heat exchange element; (c) pump means for circulating water through the system;
(d) at least one cooling tower; and
(e) storage means selected from at least one stratified storage tank or at least two storage tanks; wherein the cooling tower may be operated at night to produce cooled water that is stored in at least one of the storage tanks for subsequent use in the day.
2. The system of claim 1 wherein the system is interconnected by conduits having valve means for selectively diverting the flow of water between components of the system.
3. The system of claim 1 wherein the storage means comprises at least one stratified storage tank.
4. The system of claim 1 wherein the storagemeans comprises at least two storage tanks, one storage tank being used for storing cooled water and one storage tank being used for storing warmed water.
5. The system of claim 1 wherein the means for selectively forcing the air supply over the first heat exchange element comprises a duct, at least one bypass louver and a fan.
6. The system of claim 1 further comprising a second heat exchange element in series with the first heat exchange element, the second heat exchange element being interconnected to the system by conduits having valve means.
7. The system of claim 1 further comprising means for activating and deactivating all, or any of, the cooling tower, the pump means and the valve means.
8. The system of claim 7 wherein the activation and deactivation means is automated and is responsive to any one, or any combination of, the following:
(a) changes in cooling requirements;
(b) ambient wet bulb temperature; (c) the amount of water contained in either the stratified storage tank or the storage tanks; and
(d) the temperature of the water contained in either the stratified storage tank or the storage tanks.
9. The system of claim 1 wherein the heat exchange element comprises finned cooling coils.
10. The system of claim 1 further comprising an additional heat exchange element proximate to the first heat exchange element, the additional heat exchange element being connected to a conventional chiller.
11. The system of claim 1 further comprising an additional heat exchange element proximate to the first heat exchange element, the additional heat exchange element comprising the evaporator of a DX system.
12. An interconnected system for cooling the air supply to a building, the system comprising;
(a) a heat exchange element; (b) means for forcing the air supply over the heat exchange element;
(c) pump means for circulating water through the system;
(d) at least one cooling tower; and
(e) at least one stratified storage tank;
wherein the cooling tower may be operated at night to produce cooled water that is stored in the at least one storage tank for subsequent use in the day.
13. A method of cooling the air supply to a building, the method comprising:
(a) cooling water during the night using at least one cooling tower;
(b) storing the cooled water in storage means selected from at least one stratified storage tank, or one of two storage tanks; (c) selectively forcing the air supply across a heat exchange element, the heat exchange element being supplied with cooled water from either the stratified storage tank, or the one of two storage tanks; and
(d) storing warmed water being discharged from the heat exchange element in the stratified storage tank, or the second of two storage tanks.
14. An interconnected system for cooling the interior of a building, the system comprising:
(a) a heat exchange element disposed within the interior of the building;
(b) pump means for circulating water through the system;
(c) at least one cooling tower; and (d) storage means selected from at least one stratified storage tank or at least two storage tanks; wherein the cooling tower may be operated at night to produce cooled water that is stored in at least one of the storage tanks for subsequent use in the day.
15. The system of claim 14 wherein the heat exchange element comprises chilled slab.
16. The system of claim 14 wherein the heat exchange element comprises a chilled ceiling panel.
17. The system of claim 14 wherein the heat exchange element comprises a chilled beam.
PCT/CA2009/000033 2008-01-16 2009-01-12 Cooling system for building air supply WO2009089618A1 (en)

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US61/021,549 2008-01-16

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AR070180A1 (en) 2010-03-17
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