|Title of Invention||
A METHOD AND APPARATUS FOR GENERATING ICE SLURRY
|Abstract||A method and apparatus for generating ice slurry is disclosed. The method involves creating vacuum in an ice slurry generator using a lithium bromide vacuum absorption machine and the apparatus involves connecting the absorber of a lithium bromide vacuum absorption machine to the chamber of an ice slurry generator.|
THE PATENT ACT, 1970
(39 of 1970)
THE PATENT RULES, 2003
(See section 10 and Rule 13)
GENERATION OF ICE SLURRY IN LiBr VAPOR ABSORPTION MACHINE (VAM)
An Indian Company
of D-13, MIDC Industrial Area, R.D. Aga Road,
THE FOLLOWING SPECIFICATION DESCRIBES THE INVENTION
This invention relates to generation of ice slurry in LiBr Vapor Absorption Machine (VAM).
This invention more particularly relates to the development of configuration of Ice slurry generator and coupling it with LiBr VAM to generate ice slurry under vacuum condition.
Ice slurry is defined as a suspension of a crystallized water-based ice solution either in pure water or water containing additives like freezing point depressants. The ice slurry can be pumped. It is also called by brand names of "Liquid-ICE" or "Pumpable-ICE" or "Binary Ice" or "Flo Ice" or "Vacuum Ice". It has potential use as a secondary cooling medium, directly on product or alternatively for thermal energy storage, whilst remaining fluid enough to pump. Ice slurry offers superior performance over the conventional flake and block ice systems as a chilling medium. Ice slurry not only offers higher efficiency and cost effective ice production but also unique pumping and easy handling characteristics, provide totally sealed "Hygienic Systems" for applications in fisheries, supermarkets etc., increased production, flexibility of operating temperature and consistency of application, for optimum results.
It is already known in the prior art that ice slurry is produced by different methods, one of which is production of ice slurry under vacuum (commonly known as VACUUM ICE) utilizing triple point condition of water. The vacuum is created by using water vapor compressors. The system utilizes electricity as energy source. There are even systems where thermal
compressors have been used to create vacuum. The thermal compressors use thermal energy in the form of steam as energy source. The thermo compressors are generally low efficiency devices which require much larger quantity of steam to produce unit refrigeration effect.
On contrary, vapor absorption machines especially with double effect cycles are more efficient and consume considerably less steam to produce unit refrigeration effect.
Other types of ice slurry generators employ mechanical refrigeration for slurry production. Ice crystals are generated on refrigerated surface over which water along with freezing point depressants is flowing. Ice crystals are then scraped off mechanically from the surface to form slurry with water.
1. The main limitation of the prior art technique of ice slurry production under vacuum is the large size of water vapor compressors due to very high specific volume of water vapor under triple point condition. Another limitation is energy consumption in the form of electrical power and associated costs which are comparable to mechanical refrigerated systems.
2. The limitation of thermally driven ice slurry generators under vacuum is that low efficiency of thermo compressors resulting in very high steam consumption figures.
3. In case of mechanical systems, the surface temperatures are of the order of-10 to -15°C leading to higher electrical power consumption.
4. Another limitation of mechanical systems is that there is a much higher requirement of freezing point depressants since ice is produced at much lower temperatures.
5. LiBr VAMs are known for their limitation of producing refrigeration effect only at temperatures above the freezing point of water.
OBJECT OF THE INVENTION
It is therefore a primary object of this invention to propose a new technique of ice slurry generation which works on the principles of LiBr VAM thereby demonstrating capability of LiBr VAM's to produce ice under controlled conditions.
It is another object of this invention to propose a new configuration of ice slurry generator coupled to a LiBr VAM.
It is another object of this invention to generate ice slurry utilizing thermal energy in the form of steam which is substantially lower than what is currently available.
It is a further object of this invention to use LiBr VAM to produce ice in controlled manner which can be used as a thermal storage system in air conditioning applications.
A further object of this invention is to provide a control mechanism for producing and maintaining ice slurry under stable and homogeneous condition.
In accordance with this invention there is provide a process of ice slurry generation using LiBr VAM.
Typically the process may be for any application or may be formed by using pure water or any additive in pure water.
Un accordance with another aswpect of this invention there is provided a method of generation of ice slurry under vacuum condition, based on the principle of triple point of water, vacuum being created by LiBr VAM.
Typically, the invention envisages a configuration of ice slurry generator consisting of generator shell, agitator, defrosting mechanism, ice slurry withdrawal pipe, return pipe and ice slurry pump.
In accordance with still another aspect of this invention there is provided a method of connecting ice slurry generator to the absorber of LiBr VAM.
Specifically, this invention provides a system comprising of set of LiBr VAM components such as high temperature generator, low temperature generator, absorber, condenser, solution heat exchangers, solution pump, ice slurry generator, ice slurry pump, slurry return pipe, agitator and defrosting mechanism operably connected so as to render generation of ice slurry with the desired concentration.
BRIEF DESCRIPTION OF THE DRAWING:
The invention will now be described with reference to the accompanying drawing where,
Figure 1 shows the drawing of new ice slurry generator connected to rest of
the components of LiBr VAM.
Figure 2 shows the drawing of an alternative arrangement for figure 1.
Referring to the drawings, In figure 1 and 2, (1) is the ice slurry generator shell in which ice slurry is produced when it is subjected to triple point condition. (2) is the agitator which keeps ice slurry in homogeneous form. (3) is defrosting mechanism. (4) is ice slurry pump which is used to take away the slurry produced for the desired applications. (14) is the return pipe through which dilute ice slurry or make up refrigerant is returned to the ice slurry generator. Rest of the components namely (5) Absorber, (6) Condenser, (7) Low Temperature Generator (LTG), (8) High Temperature Generator (HTG), (9) Low Temperature Solution Heat Exchanger (LTHE), (10) High Temperature Solution Heat Exchanger ( HTHE ), (11) Heat Reclaimer (HR), (12) Interconnecting Piping, (13) Solution Pump etc. are all common as in any standard or conventional LiBr VAM.
In this cycle, the weak solution from Absorber (5) is pumped by solution pump (13 ) to (8) [HTG] via LTHE (9) and HTHE (10). Heat is added from a high temperature heat source like steam to the LiBr solution in this
generator and refrigerant is evaporated. The high temperature heat source generally at a temperature higher than 140°C can be anything like high temperature pressurized hot water, steam, direct firing of oil / gas or waste heat from any exhaust gases such as DG sets.
The stronger LiBr solution flows to (7) [LTG] via shell side of high temperature heat exchanger (10). The refrigerant generated inHTG is then condensed on the tube side of LTG, thereby providing more heat to the solution arrived from HTG. More amount of refrigerant is generated in LTG (7). The strong solution from LTG (7) is then passed back to absorber (5) via shell side of the LTHE (9) to complete the cycle.
The refrigerant vapor generated in LTG (7) is condensed in the condenser (5). This liquid refrigerant is then passed to the ice slurry generator (1) to complete the refrigerant cycle. In another version of ice slurry generator it can also be taken out of the system and replenished with the new refrigerant.
By suitable control mechanism, pressure in the ice slurry generator is maintained at triple point of water. Due to this operating condition, ice crystals are formed in the ice slurry generator. With the help of agitator, ice crystals are mixed thoroughly with the solution present in the ice slurry generator and thus ice slurry is formed. Slurry pump is used to take away slurry, once it has reached the desired concentration. The diluted ice slurry or make up refrigerant is returned to the ice slurry generator via pipe (14). Part of the ice slurry is re circulated back to the generator for maintaining stable operation and consistency of ice slurry.
1. For ice slurry generation using thermal energy, reduction in operating cost.
2. For ice slurry generation using mechanical energy, reduction in overall capital cost as well as operating cost.
3. This new concept brings in ability to LiBr VAM to act as thermal storage system which otherwise was not possible with conventional LiBr VAM.
Thus it is apparent that there has been provided, in accordance with the invention, a system that satisfies the objects, aims, and advantages set forth above. While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications, and variations as fall within the spirit and broad scope of the invention.
|Indian Patent Application Number||1399/MUM/2006|
|PG Journal Number||22/2011|
|Date of Filing||31-Aug-2006|
|Name of Patentee||THERMAX LIMITED|
|Applicant Address||D-13, MIDC INDUSTRIAL AREA, R.D. AGA ROAD, CHINCHWAD, PUNE-411 019,|
|PCT International Classification Number||F25C1/16|
|PCT International Application Number||N/A|
|PCT International Filing date|