Refrigeration – Refrigeration producer – Sorbent type
Reexamination Certificate
2000-08-22
2001-11-20
Doerrler, William (Department: 3744)
Refrigeration
Refrigeration producer
Sorbent type
Reexamination Certificate
active
06318117
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a generator of an absorption cooling system. More particularly, the present invention relates to the fluid flow pattern through the generator.
2. Description of Related Art
Typical absorption chillers have a refrigerant or working fluid consisting of at least a two-part solution, such as a solution of lithium bromide and water, or ammonia and water. Varying the solution's concentration by cyclical separation and absorption of the solution's two components allows the use of a pump, rather than a compressor, to circulate the solution through the chiller to create a cooling effect. A pump circulating a liquid solution generally requires less electrical energy or work input than other refrigerant cycles that use a compressor for compressing and circulating a comparable amount of gaseous refrigerant. However, for a given cooling effect, absorption chillers generally require more thermal energy input than other refrigerant systems that rely on compression and expansion of gaseous refrigerant. Thus, absorption chillers are often used where the savings in electrical energy out weighs the cost of the added thermal energy input.
An absorption chiller's generator uses much of the thermal energy input for separating the two components of the two-part solution. Often, a generator includes a heat exchanger in the form of coils, pipes or tubes through which steam is conveyed. For a lithium bromide and water solution, steam heat vaporizes the water out of solution, thereby leaving behind a liquid solution having a higher concentration of lithium bromide. Pressurized water vapor created by the generator then condenses upon entering an adjacent condenser. The condensed water, still pressurized, then passes through a flow restriction, which causes the water to expand to a much cooler, lower pressure water vapor. The relatively cool water vapor can then pass across a heat exchanger to cool a second fluid. The second fluid can then be used as needed, such as to cool a comfort zone of a building. The cool water vapor is subsequently reabsorbed by the higher concentrated liquid solution from the generator. This creates a solution of intermediate concentration, which is pumped back to the generator to complete the cycle.
In designing a generator for an absorption chiller, several factors need be considered. For example, lithium bromide and other absorption solutions can be expensive, thus it is often desirable to minimize the total amount of the solution in the chiller. One way to do this is to reduce the amount of the solution in the generator. However, insufficient solution in the generator can reduce a generator's efficiency, due to less heat transfer area. Insufficient solution can also create “hot spots” or areas where the steam coils of the generator rapidly heat a relatively small portion of solution. This can cause rapid, localized boiling of the solution, which can create a problem known as carryover.
Carryover is a generally undesirable effect where vaporous water entrains concentrated liquid lithium bromide solution from within the generator, and then carries the liquid over into the condenser. In some cases, evenly distributing the steam heat to the solution by increasing the liquid level of the solution in the generator can help reduce carryover. Of course, such an approach to solving the carryover problem unfortunately increases the total amount of solution in the generator.
Another problem often associated with steam-heated generators is a phenomenon known as water hammer. Water hammer is when the tubes or pipes that convey the steam through the generator produce a banging or hammering sound, due to superheated steam flash-heating condensate within the pipes. The resulting rapid expansion of the condensate causes a shockwave that creates the hammering noise. If the temperature of the steam is reduced in an attempt to avoid water hammer, the rate of heat transfer from the steam to the solution may be reduced as well. Yet, raising the temperature of the steam to reduce the amount of condensate within the steam pipes can reduce the efficiency of the generator.
Consequently, a need exists for a more efficient absorption generator that minimizes carryover, water hammer, and the e amount of solution in the generator.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an absorption chiller with a generator that conveys an absorption solution and a heat emitting fluid in a counter flow relationship to enhance heat transfer between the two and to provide other benefits.
Another object of the invention is to provide a generator that conveys steam downhill through a tube to minimize water hammer.
Another object is to place a heat emitting tube parallel to a bottom surface of a generator and tilt both the tube and the bottom surface to reduce water hammer and to simplify the construction of the generator.
Yet another object of the invention is minimize the amount of solution in a generator of an absorption chiller by varying the depth to which a heat emitting tube is submerged in the solution.
A further object of the invention is to vary the depth to which a heat emitting tube is submerged in an absorption solution of a generator to help reduce liquid carryover from the generator to a condenser.
A still further object of the invention is to provide a horizontally elongated generator that supplies a condenser with a vapor by evenly releasing the vapor across a broad area extending between opposite ends of the generator, whereby the broad, even dispersion of vapor helps reduce liquid carryover from the generator to the condenser.
Another object of the invention is to evenly distribute heat to a solution in an absorption generator by heating the solution with a tube bundle as opposed to a single tube, thereby minimizing liquid carryover from the generator to the condenser, which can be caused by violent boiling due to localized heating of the solution.
Yet another object is to enhance the heat transfer between an absorption solution and a fluid that heats the solution by conveying the solution and the heat emitting fluid in a counter flow relationship.
These and other objects of the present invention, which will better be appreciated when the following description of the preferred embodiment and attached drawing figures are considered, are accomplished in a horizontally elongated generator of an absorption chiller, wherein a heat emitting fluid and an absorption solution are conveyed through the generator in a counter flow relationship.
REFERENCES:
patent: 4315411 (1982-02-01), Vardi et al.
patent: 4343159 (1982-08-01), Vardi et al.
patent: 5253523 (1993-10-01), Bernardin
patent: 5271246 (1993-12-01), Yamauchi
patent: 5477696 (1995-12-01), Takahata et al.
patent: 5636526 (1997-06-01), Plzak et al.
patent: 6050083 (2000-04-01), Meckler
patent: 6055821 (2000-05-01), Song et al.
patent: 6098420 (2000-08-01), Furukawa et al.
patent: 6192694 (2001-02-01), Hiro et al.
Jandal Daoud A.
Lee Robin R.
Morse Michael P.
Sibik Lee L.
American Standard International Inc.
Beres William J.
Doerrler William
O'Driscoll William
Shulman Mark S.
LandOfFree
Absorption chiller with counter flow generator does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Absorption chiller with counter flow generator, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Absorption chiller with counter flow generator will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2592003