US20240133595A1 - Closed loop chiller system having single pass recycled water loop - Google Patents
Closed loop chiller system having single pass recycled water loop Download PDFInfo
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- US20240133595A1 US20240133595A1 US18/489,967 US202318489967A US2024133595A1 US 20240133595 A1 US20240133595 A1 US 20240133595A1 US 202318489967 A US202318489967 A US 202318489967A US 2024133595 A1 US2024133595 A1 US 2024133595A1
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- Prior art keywords
- water
- temperature
- condenser
- recycled
- refrigerant
- Prior art date
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 127
- 239000003507 refrigerant Substances 0.000 claims abstract description 26
- 238000001816 cooling Methods 0.000 claims description 43
- 238000010438 heat treatment Methods 0.000 claims 1
- 238000012358 sourcing Methods 0.000 claims 1
- 239000003570 air Substances 0.000 description 17
- 239000007788 liquid Substances 0.000 description 12
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 11
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 6
- 238000002156 mixing Methods 0.000 description 6
- 238000005057 refrigeration Methods 0.000 description 6
- 238000012546 transfer Methods 0.000 description 5
- 229910021529 ammonia Inorganic materials 0.000 description 4
- 239000003139 biocide Substances 0.000 description 4
- 238000005260 corrosion Methods 0.000 description 4
- 230000007797 corrosion Effects 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 238000004378 air conditioning Methods 0.000 description 3
- 229910002092 carbon dioxide Inorganic materials 0.000 description 3
- 239000001569 carbon dioxide Substances 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 239000012530 fluid Substances 0.000 description 3
- 239000003112 inhibitor Substances 0.000 description 3
- 238000009423 ventilation Methods 0.000 description 3
- 239000012080 ambient air Substances 0.000 description 2
- 230000003115 biocidal effect Effects 0.000 description 2
- 235000012206 bottled water Nutrition 0.000 description 2
- 239000003651 drinking water Substances 0.000 description 2
- 238000012423 maintenance Methods 0.000 description 2
- 238000005086 pumping Methods 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 241000589248 Legionella Species 0.000 description 1
- 208000007764 Legionnaires' Disease Diseases 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 239000002826 coolant Substances 0.000 description 1
- 230000001351 cycling effect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 230000001932 seasonal effect Effects 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
- 238000009736 wetting Methods 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B39/00—Evaporators; Condensers
- F25B39/04—Condensers
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2339/00—Details of evaporators; Details of condensers
- F25B2339/04—Details of condensers
- F25B2339/047—Water-cooled condensers
Abstract
A system for using recycled water to cool a condenser includes a water reclamation source. A water cooled condenser receives the recycled water. The received water has a first temperature. A second water at a second temperature, greater than the first temperature, is input to the water cooled condenser. The condenser heats the recycled water with the refrigerant to a third temperature greater than the first temperature and less than the second temperature, and inputs recycled water at the third temperature to the water reclamation source and lowers the temperature of the refrigerant to a fourth temperature less than the second temperature.
Description
- This application claims the benefit of U.S. Provisional Application No. 63/417,415 filed on Oct. 19, 2022. The entire contents of this application is incorporated herein by reference in its entirety.
- The present invention is directed to a structure for heat ventilation and air conditioning, and more particularly a heat ventilation and air conditioning system utilizing recycled water to act as a heat sink to cool condenser coils within the system.
- As known in the art, heat ventilation and air conditioning systems (HVAC) are the most commonly used technology to cool large buildings, commercial and industrial facilities and data centers. Chillers, the heart of the HVAC system, facilitate the transfer of heat from an internal environment to an external environment. The heat transfer device relies on the physical state of a refrigerant as it circulates through the chiller system. Chillers provide a continuous flow of coolant to the cold side of a process water system at a desired temperature of generally about 50° F. (10° C.).
- In the prior art, there are three commonly used cooling approaches for cooling condenser coils in chillers: air cooling, evaporation cooling and adiabatic cooling.
- Generally, as seen in
FIG. 1 , in an air cooledchiller 100 the refrigeration cycle starts with a low-pressure liquid/gas mix being input to anevaporator 102.Evaporator 102 acts as a heat exchange, one part chills the water and a chilled water pump 104 to pump chilled water (generally 50° F.) to air handling units of HVAC 106 that cool a building, commercial facility, data center etc. The chilled-water return from the air handling units of a building, commercial facility, data center, etc. 108 comes back toevaporator 102 to initiate heat transfer between the water and refrigerant to produce chilled water again.Evaporator 102 boils the refrigerant such as R 717 (ammonia based) and R 747 (carbon dioxide based) used in closed loop chiller systems and converts the refrigerant from a low-pressure fluid to a low-pressure gas. The low-pressure gas is input to acompressor 110 where low pressure gas compressed to high pressure gas. The high-pressure gas enters acondenser 112 where ambient air provided via air cooling fan 114 removes heat to cool the refrigerant to a liquid state. The condensed liquid passes throughdry filter 116 to remove excessive moisture prior to being input to anexpansion valve 118, which controls how much liquid refrigerant enters theevaporator 102, beginning the refrigeration cycle again. - Generally, as seen in
FIG. 2 , in an evaporative cooledchiller 200, the refrigeration cycle starts with a low-pressure liquid/gas mix being input to anevaporator 202.Evaporator 202 acts as a heat exchange, one part chills the water and a chilledwater pump 204 pumps the chilled water (generally 50° F.) to air handling units of HVAC 206 that cool a residential building, commercial facility, data center, etc. The chilled-water return from theair handling units 206 of a building, commercial facility, data center, etc. 208 comes back toevaporator 202 to initiate heat transfer between the water and refrigerant to produce chilled water again.Evaporator 202 boils the refrigerant such as R 717 (ammonia based) and R 747 (carbon dioxide based) used in closed loop chiller systems and converts the refrigerant from a low-pressure fluid to a low-pressure gas. The low pressure gas is input to acompressor 210 where low pressure gas compressed to high pressure gas. The high-pressure gas enters thecondenser 212 where condenser water (cold water) 214 provided via a cooling tower 216 that removes heat to cool the refrigerant to liquid. The condensed liquid fromcondenser 212 passes through adry filter 218 to remove excessive moisture prior to entering anexpansion valve 220, which controls how much liquid refrigerant enters the evaporator, beginning the refrigeration cycle again. - While
condenser water 214 cools thecondenser coils 212, it subsequently generates a warm water stream also known ascondenser water return 222 which is pumped to a cooling tower 216 to cool the content. As water is cooled in cooling tower 216, thewarm air 224 is concurrently released into atmosphere. Adosing station 226 provides corrosion inhibitors and biocide for corrosion control and Legionella control in cooling tower 216. Cooling tower 216 is designed to operate a few cycles to reduce water consumption. As more cycles is achieved dissolved solids concentrate in thecondenser water 214 which requiresperiodic blowdown 228 to discharge the blowdown, generally to a sewer, to avoid excessive dissolved solids accumulation in cooling tower 216. To compensateevaporative losses 224 andblowdown losses 228, in cooling tower 216, a makeup water in the form of potable water or recycled water 230 is provided. A makeupwater storage tank 232 stores and conveys the makeup water 230 to cooling tower 216 water storage basin. A blend of make up water 230 and cooledwater 214 from the cooling tower 216 are input to condenser 212 to remove heat returning fromcompressor 210. - The prior art air cooling systems have been satisfactory however they suffer from the disadvantage that they are energy inefficient. During peak use seasonal periods, chillers consume more than fifty percent of a building's electrical energy. It is estimated that more than 120,000 chillers in the United States are expending a further thirty percent of building energy due to operational inefficiencies.
- Evaporative cooling chiller systems are more efficient as a result of their advantageous heat absorption capacity. However, they suffer from the disadvantages that they require high water consumption because of evaporative losses. Additionally, they are relatively more complex to operate and maintain; requiring continuous use of cooling tower chemicals such as corrosion inhibitor and biocides, as well as requiring structure for disposal of blowdown steam. Therefore, they require a higher initial investment as compared to air cooling systems.
- An adiabatic cooling system (not shown) is an air cooled system assisted by evaporative cooling. Wetting installed cooling pads, via water, pre-cools the ambient air, allowing a more efficient air cooling system. While the adiabatic cooling system is more energy and water efficient than air cooling and evaporative cooling it suffers from the disadvantage that it is more complex in operation and requires biocides, increasing the maintenance requirements.
- Accordingly, a structure and methodology to overcome the shortcomings of the prior art, is desired.
- A system for using recycled water to cool a condenser includes a water reclamation source. A water cooled condenser receives the recycled water. The received water has a first temperature. A refrigerant at a second temperature, greater than the first temperature, is input to the water cooled condenser. The condenser heats the recycled water with the refrigerant to a third temperature greater than the first temperature and less than the second temperature, and inputs recycled water at the third temperature to the water reclamation source and lowers the temperature of the refrigerant to a fourth temperature less than the second temperature.
- In a further embodiment of the invention the second water is water returned from HVAC systems for commercial building, data center and other large cooling operations. The first water may be returned to the water reclamation source after passing through the cooled condenser.
- The present disclosure will be better understood by reading the written description with reference to the accompanying drawing figures in which like reference numerals denote similar structure and refer to like elements throughout in which:
-
FIG. 1 is an operational diagram of an air cooled chiller constructed in accordance with the prior art; -
FIG. 2 is an operational diagram of an evaporative cooled chiller constructed in accordance with the prior art; and -
FIG. 3 is a system diagram of a cooling system constructed in accordance with the invention; - Reference is now made to
FIG. 3 in which a system, having two independent loops, generally indicated as 300 and 500, for chilling water for use in an HVAC system in accordance with the invention is provided. System 300 (lower loop) is a typical closed loop chiller system used in HVAC systems of commercial facility, data center, etc.System 500 includes awater reclamation plant 502 for generating and conveying recycledwater 504 to a flow distribution and recycledwater pump station 506 and pumping the required recycled water as condenser water supply 508 to be used in connection withsystem 300 to cool condenser coils 312 a of acondenser 312 of achiller system 500.System 500 also includes a blending and waterreclamation pumping station 512 which enables blending of the recycledwater 510 that is not used for cooling purpose with the warm recycledwater 520 generated from the cooling process as described below.Water reclamation plant 502 acts as a water reclamation source and treats wastewater to generate unrestricted recycled water in accordance with local state laws, such as California Title 22 and Arizona Class A Recycled Water and all other states making recycled water eligible for cooling and other all purpose non potable and other beneficial reuse purposes. - In the invention presented in
FIG. 3 , in a closed loop chiller with single pass recycledwater loop 500 to cool the condenser coils 312 b, the refrigeration cycle starts with a first closedloop 300 having a low-pressure liquid/gas mix being input to anevaporator 302.Evaporator 302 acts as a heat exchange, one part chills the water and achilled water pump 304 pumps the chilled water (generally 50° F.) to air handling units ofHVAC 306 that cool a building, commercial facility, data center or the like. - A
chilled water return 308 from the air handling units of HVAC of a building, commercial facility, data center, etc., fluidly connected toevaporator 302 returns chilled water toevaporator 302 to initiate heat transfer between the water and refrigerant to produce chilled water again.Evaporator 302 boils the refrigerant such as R 717 (ammonia based) and R 747 (carbon dioxide based) used in closed loop chiller systems and converts the refrigerant from a low-pressure liquid to a low-pressure gas. Acompressor 310 receives the low-pressure gas and compresses the low-pressure gas into high pressure gas. - A
condenser 312, in fluid communication with thecompressor 310, and a flow distribution and recycledwater pump station 506, receives the high pressure high temperature gas from thecompressor 310. The flow Distribution and recycledwater pump station 506 pumps recycled water as the condenser water supply 508 to the cooling coils 312 a ofcondenser 312. The condensed liquid from coils 312 b ofcondenser 312 passes through adry filter 320 to remove excessive moisture prior to being input to anexpansion valve 322, upstream ofevaporator 302, which controls how much liquid refrigerant enters theevaporator 302, beginning the refrigeration cycle again - In a second
closed loop 500, recycled water as condenser water supply source (cold) 508, as discussed above, is input to condenser coils 312 a ofcondenser 312 to cool the condenser coils 312 b ofloop 300. As a result heat is concurrently transferred from hot refrigerant to recycled water and it exists condenser as condenser water return (warm) 514, generally 10° F. warmer than the recycled water used as the condenser water supply source 508. As known in the art refrigerant may be water, fluorocarbons, hydrocarbons, even ammonia, or any combination thereof. - Depending upon season and relative contributions of
condenser water return 514 andrecycled water 504 generated atwater reclamation plant 502, thecondenser water return 514 either passes through aheat exchanger 516 or bypass 518 aroundheat exchanger 516 before entering the blending and reclaimedwater pump station 512.Heat exchanger 516, if used, can reduce the temperature ofcondenser water return 514 by typically 3° F. and produces a cooled condenserwater return stream 520. - The flow distribution and recycled
water pump station 506 has two functions: (1) It pumps the needed amount of condenser water supply source (recycled water) 508 to the condenser coils 312 and (2) conveys the remainingrecycled water 510 to the blending and waterreclamation pump station 512. Once the amount of condenser water supply for cooling is determined, the remainingrecycled water 510 is calculated by taking flow difference betweenstream 504 and stream 508. - The blending and water
reclamation pump station 512 receives flow streams fromstreams non-potable reuse purposes 522. The recycled water temperature in blending and waterreclamation pump station 512 may increase to a value that is dependent upon flow and temperature of the two streams (510 and 520) and it falls within the temperatures of thestreams - By constructing an HVAC system in accordance with the invention a simplified, more efficient cooling system is provided as there is no longer a need for a cooling tower of the evaporative system or energy intensive compressor condenser systems of the air cooled chiller systems. Furthermore because of its single loop and closed nature the above system lends itself to the use of recycled water only once without cycling it several times and without spraying the water and does not need to make us of complex biocide, corrosion inhibitor or other treatment systems significantly reducing operation and maintenance needs and associated costs for condenser cooling.
- A system for using recycled water as condenser water supply source, in accordance with the invention, provides a condenser in a closed loop chiller system in HVAC systems for commercial building, data center and other large cooling operations; recovering and utilizing recycled water from cooling operation that eliminates potable water use for cooling, eliminates need for cooling tower, reduces cost and complexity of the evaporative cooling, eliminates evaporative water losses and maximizes recycled water available for community; offering highly innovative and sustainable solution for commercial building, data center and large industrial scale cooling.
- It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in carrying out the above method and in the construction set forth without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
- It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.
Claims (2)
1. A system for using recycled water to cool condenser in a chiller comprises:
a water reclamation source for sourcing recycled water;
a water cooled condenser receives the recycled water from the water reclamation source, recycled water having a first temperature; the a water cooled condenser receiving a refrigerant, the second water having a second temperature, greater than the first temperature, the condenser heating the recycled water with the refrigerant to a third temperature greater than the first temperature and less than the second temperature, and inputs recycled water at the third temperature to the water reclamation source, and lowers the temperature of the refrigerant to a fourth temperature less than the second temperature.
2. The system of claim 1 , wherein refrigerant is water returned from an HVAC system for commercial building, a data center or other large cooling operations.
Publications (1)
Publication Number | Publication Date |
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US20240133595A1 true US20240133595A1 (en) | 2024-04-25 |
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