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
  • F25B15/00—Sorption machines, plants or systems, operating continuously, e.g. absorption type
  • F25B15/02—Sorption machines, plants or systems, operating continuously, e.g. absorption type without inert gas
  • F25B15/04—Sorption machines, plants or systems, operating continuously, e.g. absorption type without inert gas the refrigerant being ammonia evaporated from aqueous solution
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K5/00—Heat-transfer, heat-exchange or heat-storage materials, e.g. refrigerants; Materials for the production of heat or cold by chemical reactions other than by combustion
  • C09K5/02—Materials undergoing a change of physical state when used
  • C09K5/04—Materials undergoing a change of physical state when used the change of state being from liquid to vapour or vice versa
  • C09K5/047—Materials undergoing a change of physical state when used the change of state being from liquid to vapour or vice versa for absorption-type refrigeration systems
• • 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
  • F25B15/00—Sorption machines, plants or systems, operating continuously, e.g. absorption type
  • F25B15/02—Sorption machines, plants or systems, operating continuously, e.g. absorption type without inert gas
  • F25B15/06—Sorption machines, plants or systems, operating continuously, e.g. absorption type without inert gas the refrigerant being water vapour evaporated from a salt solution, e.g. lithium bromide
• • 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
  • F25B27/00—Machines, plants or systems, using particular sources of energy
  • F25B27/002—Machines, plants or systems, using particular sources of energy using solar energy
  • F25B27/007—Machines, plants or systems, using particular sources of energy using solar energy in sorption type systems
• • 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
  • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
  • Y02A30/00—Adapting or protecting infrastructure or their operation
  • Y02A30/27—Relating to heating, ventilation or air conditioning [HVAC] technologies
• • 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
  • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
  • Y02A30/00—Adapting or protecting infrastructure or their operation
  • Y02A30/27—Relating to heating, ventilation or air conditioning [HVAC] technologies
  • Y02A30/272—Solar heating or cooling
• • 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
  • Y02B10/00—Integration of renewable energy sources in buildings
  • Y02B10/20—Solar thermal
• • 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]
  • Y02B30/62—Absorption based systems
• • 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
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P20/00—Technologies relating to chemical industry
  • Y02P20/10—Process efficiency

Definitions

• the present invention relates to an absorption water chiller, which uses the lithium ammonia-nitrate mixture as a refrigerant-absorbent pair and in which all the heat exchangers of the equipment are heat-exchanged plate heat exchangers.
• the water chiller It is an absorption water chiller that operates according to a single-effect cycle designed to incorporate solar energy into air conditioning applications complying with the cooling requirements of buildings for maximum powers of 15 kW.
• the water chiller can operate in water-water mode or in air-water mode depending on the needs of the installation.
• the current technology of the absorption equipment is based on the use of the two conventional mixtures of the absorption cycles: H20-LiBr and NH3-H20.
• the H20-LiBr mixture has the advantage of offering a higher operating coefficient (COP) at lower generation temperatures 75-90 ° C.
• COP operating coefficient
• it has the disadvantage that it requires a cooling tower since at high temperatures of the absorber it presents crystallization problems.
• the need for cooling tower makes equipment more expensive, introduces a consumption of water from 4 to 6 kg / h per Kw. cold and increases maintenance costs associated with compliance with the legislation on the prevention of legionella.
• the NH3-H20 mixture does not present crystallization problems as the mixture is soluble in the entire concentration range. This allows a dry dissipation although at the cost of higher activation temperatures than H20-LiBr equipment. Therefore, the NH3-H20 absorption equipment requires higher temperature solar collectors that make the installation more expensive.
• Another drawback of the NH3-H20 absorption equipment is the relative volatility of the water (absorbent) that forces the vapors to be rectified at the generator outlet so that pure ammonia reaches the evaporator. This rectification, which is essential since the presence of water in the evaporator reduces its cooling capacity, penalizes the COP of the cycle that turns out to be lower than that of the H20-LiBr cycles.
• the limitations presented by the two traditional mixtures of absorption cycles have motivated the proposal and investigation of new mixtures. These include the mixtures that keep the ammonia as a refrigerant propose the replacement of water as an absorbent with a salt to eliminate the need to rectify the vapors at the generator outlet.
• the present invention proposes the use of lithium nitrate as an ammonia absorbent.
• the advantages of the NH3-L ⁇ N03 mixture over conventional mixtures are: a) In comparison with the H20-LiBr mixture it has no crystallization problems with air cooling and the cycle operates at pressures above atmospheric. b) Compared to the NH3-H20 mixture, it does not require rectification and the cycle activation temperatures are lower.
• the present invention makes it possible to activate the absorption cycle with hot water produced in solar collectors with temperatures between 80 and 1 0 ° C and also incorporates significant improvements that allow a reduction of the inconveniences which presents the state of the art in the field: a) The possibility of crystallization of the working fluid. b) The operation under vacuum conditions of the water-lithium bromide mixture. c) A difficult refrigerant-solution separation in the ammonia-water mixture. d) Finally, it is also intended to solve part of the inconveniences associated with the use of a water-water chiller, such as the use of a cooling tower, an aero-coolant or any other heat sink involved in the installation large space needs or hygienic-sanitary problems.
• the "Water-by-water or water-water absorption chiller of Ammonia and Lithium Nitrate consists of an absorption water chiller system that uses the ammonia nitrate nitrate mixture as a cooling-absorbent pair, in which all the heat exchangers of the equipment are heat-exchanged plate heat exchangers, improving the heat and material transfer processes and forming a simple effect cycle designed to incorporate solar energy into air conditioning applications, also allowing to address the cooling requirements of buildings for maximum powers of 15 kW.
• plate bubble absorber plate flow boiling generator, plate condenser and evaporator, plate heat exchanger and vapor exchanger, ammonia vapor separator tank and solution flow self-regulating valve.
• ammonia will be the refrigerant while as an absorbent the lithium nitrate will act when treated, the latter of a salt with a high affinity for ammonia vapor.
• the water chiller can operate in water-water mode or in air-water mode depending on the needs of the installation.
• This is achieved by having two models of absorption chiller, air-water and water-water, capable of adapting to the needs of any installation.
• all heat exchangers are corrugated plate exchangers.
• the air-water model two alternatives are distinguished, the first is to use an imbricated battery, so that part of it is used to condense refrigerant ammonia and the rest to cool the cooling water of the chiller absorber.
• the second alternative is to have a battery designed to cool the cooling water from both the condenser and the absorber.
• Figure 1 Diagram of the water-water absorption cooling process.
• Figure 2 a - Scheme of the refrigerant and solution distribution system located at the entrance of the absorber-Plant.
• Figure 2 b - Scheme of the refrigerant and solution distribution system located at the intake of the absorber-Elevation.
• Figure 2 d - Scheme of the refrigerant and solution distribution system located at the entrance of the absorber-Profile seen from the left.
• Figure 2 e - Scheme of the refrigerant and solution distribution system located at the entrance of the absorber-Profile Detail A.
• Figure 2 f - Diagram of the refrigerant and solution distribution system located at the absorber inlet-Profile Detail B.
• Figure 3. Diagram of the air-water absorption cooling process.
• Figure 4. Diagram of the cooling process by air-water absorption type with imbricated battery.
• Figure 5 a - Condenser configuration according to steel imbricated battery - Plant.
• Figure 5 b - Condenser configuration according to steel imbricated battery - Profile.
• Figure 1 shows how it consists of the following components: a generator (1 1) where, thanks to the heat supplied by solar collectors, refrigerant vapor is obtained, which will be separated from the solution formed by lithium refrigerant-nitrate, thanks to a tank located behind the generator (12), a condenser (1) for the steam from the previous tank, a storage tank (2) of the condensed refrigerant from the condenser, a subcooler (3) for the liquid refrigerant at the outlet of the tank, a valve (4) to decrease the pressure of the refrigerant, an evaporator (5) that will re-gasify the liquid refrigerant that will pass, after circulating through the exchanger (3), to an absorber (7) in which amoni is absorbed pure coupling in a low concentration solution (Line 8), so that a rich solution is obtained (Line 1)
• a generator (1 1) where, thanks to the heat supplied by solar collectors, refrigerant vapor is obtained, which will be separated from the solution formed by lithium refrigerant-
• the coolant vapor phase is produced from the coolant-lithium nitrate solution by means of a generation device composed of a corrugated plate exchanger followed by a tank where the separation of the two phases occurs, coolant vapor and poor solution of refrigerant-lithium nitrate, obtained in the heat exchanger thanks to the heat input of a stream of hot water from the solar collectors and circulating in countercurrent with the solution.
• the solution circulates upwards in the plate exchanger.
• the hot water inlet temperature will comprise values between 80 and 1 1 0 Q C.
• connection between the separator tank (12) and the condenser (1) is produced in such a way that the steam outlet is located at the top of the tank to prevent liquid circulation in the line (9), while the outlet of Liquid is located at the bottom of the tank.
• This vapor condenses on a plate changer to obtain saturated liquid ammonia that is stored in the tank (2).
• the steam can also be condensed in a battery-type heat exchanger of finned steel tubes.
• the refrigerant as saturated liquid will circulate through the plate exchanger (2) to achieve subcooling conditions and will feed the expansion valve electronics (4), located at the inlet of the evaporator (5), to reduce its pressure as can be seen in Fig. 1.
• the subcooled liquid from the valve (4) will be gasified thanks to the heat supplied by a stream of cold water from the building to be cooled.
• the cold water supply temperature can take values between 8 and 15 Q C, depending on the building's air conditioning system.
• a device consisting of a corrugated plate exchanger
• the vapor refrigerant and the poor solution enter through one of the lower connections of the exchanger, the rich solution leaving the upper connection.
• the heat generated in the absorption process is dissipated by the cooling water that circulates in countercurrent. Due to the low speeds existing at the absorber inlet port, there is a risk that the poor solution and the steam entering the absorber will separate and enter through different channels. To avoid this problem, steam is injected into the inlet port through a distribution system.
• a diagram of the refrigerant and solution distribution system located at the inlet of the absorber is shown in Figures 2a, 2b, 2c, 2d and 2f.
• the distribution system starts with a T that connects the refrigerant vapor line and the poor solution line.
• the steam line smaller in diameter than the exchanger port, extends to the end of the inlet port of the exchanger.
• the end of the tube is clogged and in the lower part of the tube a trapezoidal opening has been made with a smaller opening at the beginning of the distribution port to widen towards the end of the port.
• the steam outlet area through the opening made in the lower part of the tube is slightly larger than the passage area of the tube.
• the tube referred to by way of example could be carried out according to an outside diameter of 1 9.05 mm and an inner diameter of 16.57 mm, with a trapezoidal opening at the beginning of the port of 0.2 cm and 0.3cm at the end of the port.
• the solution circulates through the annular zone between the steam tube and the distribution port of the exchanger.
• the biphasic flow that is generated then circulates in the channels of the plate exchanger where the absorption process takes place.
• the heat generated in the absorption process is dissipated by a stream of cooling water that circulates countercurrently with the solution.
• the inlet temperature of the cooling water to the condenser and absorber will comprise values between 35 and 45 Q C.
• the result of the absorption is a refrigerant-salt solution with a high concentration of ammonia and will be stored in a tank (8) located at the outlet of the absorber (7). This solution will circulate through the line (2) to go to the circulation pump (9) which will increase its pressure to the high pressure of the absorption cycle.
• the solution rich in ammonia and from the circulation pump (9) will increase its temperature in the exchanger (10) thanks to the counter current flow with the solution poor in ammonia from the tank (12). Finally, the ammonia-rich solution will pass to the generator and the poor solution, after passing through the expansion valve (13), will feed the steam (14) to the absorber, thanks to the special distributor located at its inlet.
• this refrigeration process scheme only differs from those described in Figure 1 and Figure 3 in the configuration of its condenser.
• the condenser is an imbricated steel battery as shown in Figures 5a, 5b and 5c, in which part of it is intended to condense the refrigerant and the rest to dissipate the heat of the cooling water.
• the battery consists of two rows of steel tubes with aluminum fins. One of the rows will be dedicated to condense ammonia and the other to cool cooling water. Each fluid that circulates through the battery (ammonia and water) will travel a different circuit according to the needs of the process. The battery will be curved according to the spatial needs of the water chiller structure.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Sustainable Energy (AREA)
• Life Sciences & Earth Sciences (AREA)
• Sustainable Development (AREA)
• Materials Engineering (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Combustion & Propulsion (AREA)
• Organic Chemistry (AREA)
• Sorption Type Refrigeration Machines (AREA)

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Cited By (2)

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• 2009
  • 2009-09-29 ES ES200930758A patent/ES2356542B1/es not_active Expired - Fee Related
• 2010
  • 2010-09-21 WO PCT/ES2010/070608 patent/WO2011039397A1/es active Application Filing
  • 2010-09-21 IN IN2686DEN2012 patent/IN2012DN02686A/en unknown
  • 2010-09-21 EP EP10819944.9A patent/EP2484992B1/en active Active
  • 2010-09-21 ES ES10819944T patent/ES2782356T3/es active Active

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