FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
The Patent Rules, 2003
Complete Specification
(See section 10 and rule 13)
A Novel System For Cooling Faints Used In Industrial Painting
Processes
Mahindra and Mahindra Ltd.
An Indian company registered under the Indian Companies Act, 1956. Mahindra Towers, R.K. Kurne Chowk, Worli, Mumbai - 400 018, Maharashtra, India
The following specification particularly describes the invention and the manner in which it is to be performed.

A Novel System For Cooling Paints Used In Industrial Painting Processes
Field of Invention:
The present invention relates to tapping solar energy and using it to operate a chilling machine to cool the painting systems in the paint shops used in industrial units such as those used for manufacture of automotives, white goods, other household or industrial appliances that require painting. In particular the present invention related to reducing the load on the chillers used in industrial applications such as paint shops where paint that gets heated while painting articles or paint circulation, needs to be maintained at a certain cooler temperature range. However, the present invention is applicable to any applications that require a cooling operation.
Background of Invention:
Paint shops conventionally use electrically operated chillers to cool the paints. The chillers run on vapor compression principle. These chillers, which are normally electrically operated, typically consume large amount of electrical. This results in huge operating costs and also adds to CO2 emissions. An alternative system that could reduce these operating costs and also reduce the adverse environmental impact would be valuable to any industry that has cooling operations. There is therefore a need to have an alternative cooling source which would reduce / eliminate the costs and the environmental impact.

Objects of the invention:
Accordingly, one of the objects of the present invention is to tap heat from the sun in a useable form.
Another object of the present invention is to use the tapped heat towards the operation of a chiller that would reduce the operational costs and the adverse environmental impact
Summary of the invention:
A system is therefore proposed to harness the solar energy. The system uses a number of solar concentrators preferably working on principle of 'Scheffler's reflector'. This tapped heat is used to power a chilling machine, preferably working on 'Vapor absorption principle', and termed hereinafter as a solar vapour absorption machine or a SVAM,. The chilling effect created by this machine is used to cool a paint system through a set of heat exchangers which work on liquid to liquid heat transfer principle. The system disclosed here may be used in any other process that requires cooling of liquids.
Brief Description Of Figures:
Figure 1 shows conventional systems incorporating chillers and cooling towers deployed in paint shops
Figure 2 shows the system of present invention

List Of Parts:
Solar concentrator - '. Cooling tower - 7
Solar collector - 2 First loop - 8
Solar vapour absorption machine - 3 First piping network - 8 A
First evaporator - 3 A Second loop - 9
Heat generator - 3B Third loop - 10
First condenser - 3C Fourth loop - 11
Paint tanks - 4 Third piping network - 11A
Heat exchanger - 5 Fifth loop - 12
Chiller - 6 Fourth piping network - 12 A
Second evaporator - 6A Sixth loop - 13
Second condenser - 6B Second piping network - 13A
Detailed Description Of Invention:
The conventional process of using a number of electrically powered chillers working on 'vapor compression principle' is shown in Figure 1.
It shows a first loop (8) formed between the paint tanks (4) containing paints in which articles to be painted are immersed and heat exchangers (5) that cool the hot paint. This is a semi closed loop formed by a network of pipes that circulates paint through the heat exchangers (5) and brings it back to the paint tanks (4). The temperature of the paint throughout the loop is maintained between 25 to 30 °C.

Figure 1 also shows a second loop (9), which is a closed loop of liquid formed between the set of heat exchangers (5) and evaporators (6A) of a set of chillers (6). The fluid in this loop, also termed as the chilling water loop, is cooled to 7°C after exchanging the heat with the refrigerant in the chiller. The cooled fluid is returned to the set of heat exchangers (5) where it collects the heat from the paint from the paint tanks (4) and gets heated to a temperature of 12 °C, which is sent to the evaporators (6A) of the chillers, thereby completing this closed loop.
There's a third loop (10) in operation in the conventional systems. This loop is formed between the second condensers (6B) of the chillers (6) and the cooling tower (7). This is a semi open loop wherein the water coming to the cooling tower (7) from the condensers (6B) of the chillers (6) is at 37 °C which cools down to 32 °C after passing through the cooling tower (7) and is returned to the second condensers (6B). These three loops form the conventional system of cooling a fluid such as paint in an industrial application.
Figure 2 describes the system of the present invention. It introduces a solar vapour absorption machine (SVAM) (3), which serves as a heat generator as well as a cooler of fluids. It generates hot fluids in this process, which are cooled using the conventional cooling towers (7). The energy balance of SVAM (3) is such that the system results in substantial amount of net saving of energy over the conventional systems.

Figure 2 shows a fourth loop (11) that circulates fluids between the SVAM (3) and a system of solar concentrators (1) and collectors (2). It's a closed loop that provides energy to the generator section (3B) of SVAM that forms a part of the SVAM system (3). The SVAM (3) also has a condenser unit (3C) and an evaporator unit (3A) much as a typical chiller has.
A fifth loop (12) circulates fluids between a first condenser (3C) of the SVAM (3) and the condensers (6B) of the set of chillers (6) via a cooling tower (7). The fluid entering the cooling tower (7) cools down before entering the condensers (6B) of the chillers (6). The water leaving the condensers (6B) of the chillers (6) heats up while passing through the condensers (3C) of the SVAM (3), and which is sent to the cooling tower (7) for cooling, as we saw earlier. The cooling tower (7) effectively cools down the water coming out of condensers (6B) of both the chillers (6) and the SVAM (3). This puts additional load on the cooling tower (7) of the present invention as compared to that of conventional systems, however, as will be seen later, this is more than compensated by the reduced load that the chillers (6) of the invention experience which results in substantial net saving of energy for the system as a whole.
Figure 2 also shows a sixth loop (13) that is formed between the evaporators (6A) of the chillers (6), the set of heat exchangers (5), and the evaporator (3A) of the SVAM (3). The fluid passing from the evaporators (6A) of the chillers (6) and the

heat exchangers (5) is of the lowest temperature in this entire loop. It is this fluid which cools the hot paints or any fluid that needs cooling. In the process, it heats up as it emerges out of the heat exchangers (5) and goes to the evaporator (3 A) of the SVAM (3). The fluids that emerge out of the evaporator (3A) of the SVAM (3) have cooled down during their passage through the SVAM evaporator (3A) and reach the evaporators (6A) of the chillers (6) where they cool down further before emerging out of the evaporators (6A) of the chillers (6) and going to the heat exchangers (5). This completes the sixth loop (13).
The present invention also incorporates a first loop (8) that is similar to the earlier one described for the conventional systems.
It should be noted that the SVAM (3) is placed in series of the electrically operated chillers, in the return loop. The SVAM (3) takes up the part load of chilling by cooling the return water at 12 °C to up to 10.5 °C. This partly cooled water is further sent to the electrically powered chillers to further cool it to 7 °C.
The heat exchanger (5) used in the present invention could be a plate heat exchanger or the shell and tube type heat exchanger. As discussed earlier, the paint loop is a semi closed loop as the cooled paint delivers the paint in the tank. The paint in the tank is thus exposed to the atmosphere, although the paint tank (4) may be covered with lid or enclosure.

The SVAM (3) is powered with the help of a hot water circuit (First loop). This hot water of 147°C is generated with the help of solar concentrators (1) and collectors (2). After powering the SVAM (3) it returns back to the solar concentrators (1), thus completing a closed loop. The concentrators (1) are in principle the Scheffler's reflectors, which concentrate the sun rays on a collector (2). The collector (2) is an enclosed shell through which water is passed. This water inside gets heated in turn as the shell is heated from outside by the concentrated sun rays.
A heat pump used in the present invention is a machine which operates on vapor absorption principle. As we have seen earlier, it uses the solar heat for its operation and termed as a solar vapour absorption machine, or the SVAM (3). Figure 3 explains the workings of the SVAM (3). The SVAM (3) uses water as refrigerant and lithium bromide as carrier. The refrigerant absorbs the heat in its evaporator section which is essentially a shell and tube type heat exchanger. The refrigerant absorbs heat from the external water circuit called as chilled water in figure 4. Here it converts in to a vapor after evaporation and passes on to the next section, the absorber section. This section also essentially a shell and tube type heat exchanger. The heated lithium bromide, coming from the generator section, also enters absorption section and absorbs the water vapor and also rejects heat to a cooling water loop. The liquid solution of water and lithium bromide, called as diluted solution, is then is carried to the generator section, which is again a shell

and tube type heat exchanger. Here the solution is heated and the water evaporates and separates out from the lithium bromide. The heating of the solution can be done by number of sources of energy like, LPG, HSD, Steam, Hot water or even waste hot gases. In our invention the heat source is the hot water, generated by the solar energy. The concentrated lithium bromide solution then passes on to the absorber section thus completing a closed loop. The evaporated water passes on to the condenser, again a shell and tube type heat exchanger to get cooled and condensed. The heat is rejected to the same cooling water loop which also passes through the absorber section. The condensed water is now sucked in to the evaporator, which is maintained at vacuum pressure, and vaporized. During vaporization it absorbs heat from the chilled water loop.
The evaporator and absorber sections form the lower shell of the heat pump and are typically maintained at a pressure (vacuum) of 6 to 7mm of Hg. The generator and condenser form the upper shell. The upper shell is maintained at about 70mm of Hg.
It is observed by the inventors that such a SVAM (3) running on solar power may or may not be sufficient to fulfill the cooling requirements of the paints or any other processes. Thus a provision for additional source of chilling is made in form of electrically operated chillers. The placement or the orientation of the chillers is made in a way so that maximum utilization of the solar powered SVAM (3) is done. The solar powered SVAM (3) is placed in series and before of the

electrically powered chiller (6) so that the SVAM (3) utilization is optimal or rather the utilization of the electrically operated chiller (6) is minimum. This results in the reduction in electrical power consumption.
The pipe network may carry any fluids for heat transfer, preferably liquids, more preferably water.
All the equipment in the system like the chillers (6), SVAM (3) and heat exchangers (5) work in synchronization and are elaborately automated. Complete system is controlled by PLC unit (not shown) and feedback given to and taken from any equipment enables the operation of the complex system. To maintain the required flows of liquids through the loops appropriate sized pumps are provided.
Example of the invention:
The invention was deployed in two separate paint shops installations located adjacent to each other. The first paint shop had overall physical plan dimensions of 330m x 116m. The second paint shop had plan dimensions of 200M x 50m.
The length of piping involved in the solar energy tapping process was approximately 300m. A pipe size of 300NB was laid for this purpose. The water was circulated through the hot water close loop at a rate of 400 m3/hr.

The input water temperature to the SVAM was at 147°C. After powering the SVAM the temperature of the water returning to the solar concentrators was of 140 °C. The chilled water passing through the evaporator of the SVAM was entering at 12°C and leaving at 10.5 °C. This water further entered the electrically powered chillers to further get cooled to 7 °C. The electrically powered chillers were placed in parallel configuration to each other. Each chiller was capable of generating maximum of 154 tons of refrigeration.
The Paint lines that were cooled in the two paint shops were located at 4 different points (2 each in each paint shop) away from each other. The distance of one user point to the other was approximately 60m. A pipeline of 550m length with a diameter of 200-NB was laid send the cooling water till the paint line heat exchangers and bring it back to the chillers. A flow of 270 m3/Hr was maintained through this loop of water. The paint volume need to be cooled in first paint shop was about 400m3 and 100m3 respectively at two different locations about 100m apart from each other and in the other paint shop the paint volume needed to be cooled was 235m3 and 35m3 respectively at two different locations 60m apart from each other. The SVAM used in the set up could generate a capacity of up to 160t of refrigeration depending upon the availability of the sunlight. Thus total installed capacity of chillers was 468t.

There were 70 Scheffler's collectors, alternatively, sometimes called as solar dishes in the solar yard, each having capacity to generate up to 4200 Kcal /hr of heat. Thus all the dishes put together could generate up to 2,94,000 Kcal/hr of heat. As per the study made for the availability of the sunlight, the SVAM (3) would operate for 2200 hours in a year and generate 110 tons of refrigeration on an average and supplement the chilling operations of the electrically operated. This would save up to 2,00,000 units of power per year. We consume additional energy of the order of 15000 units per year for additional cooling of the cooling water (5th loop).
It is thus obvious from the foregoing discussion that the present invention saves a huge amount of energy by harnessing the solar energy in a way that has not been implemented hitherto. The invention is applicable to all industrial processes that involve cooling of fluids. It is also evident that the present invention describes the following embodiments:
1) A system of cooling paint used in the industrial painting processes, said system comprising at least one solar concentrator (1),, a set of solar collectors (2), a solar vapour absorption machine (3), a set of heat exchangers (5), a set of chillers (6), and a cooling tower (7), characterized in that the heat energy tapped from the sun by said solar concentrators (1) and solar collectors (2) is used to operate the solar vapour absorption machine (3), and chillers (6) are used to supply chilled fluid to heat

exchangers (5) which cool the paints, heat exchangers (5) are connected to said solar vapour absorption machine (3), which in turn is connected to said cooling tower (7) to which said chillers (6) are also connected.
2) A system of cooling paint as described in embodiment 1, wherein a first loop (8) is formed between the paint tanks (4) containing said paint, and said set of heat exchangers (5), said first loop (8) being an open loop which is formed with a first piping network (8A) between said paint tanks (4) and said set of heat exchangers (5), said paint tanks (4) being a part of said first loop (8).
3) A system of cooling paint as described in embodiments 1 and 2, wherein a sixth loop (13) is formed between said set of heat exchangers (5) and the first evaporator (3 A) of said solar vapour absorption machine (3); said first evaporator (3 A) and the second evaporators (6A) of said set of chillers (6); and said second evaporators (6A) and said heat exchangers (5); said sixth loop (13) being a closed loop formed using a second piping network (13A).
4) A system of cooling paints as described in embodiments 1 to 3, wherein a fourth loop (11) is formed between said set of solar collectors (2), and a generator section (3B) provided in said solar vapour absorption machine

(3), said fourth loop (11) being a closed loop and formed using a third piping network (11 A).
5) A system of cooling paints as described in embodiments 1 to 4, wherein a fifth loop (12) is formed between a first condenser (3C) which is a part of said solar vapour absorption machine (3), said cooling tower (7), and the second condensers (6B) that form a part of respective said chillers (6), said fifth loop (12) being a open loop formed by a fourth piping network (12A) and the said cooling tower (7).
6) A system of cooling paints as described in embodiments 1 to 5 wherein the solar heat is concentrated on said set of solar collectors (2) said solar reflectors and collected heat is transferred to said generator section of SVAM (3) through hot water via said fourth loop (11).
7) A system of cooling paints as described In embodiments 1 to 6, wherein said solar vapour absorption machine (3) cools the water received into said first evaporator (3A) before sending it on to said set of second evaporators (6A) wherein water is further cooled before it is sent to said set of heat exchangers (5) for the purpose of cooling paint.

8) A cooling system as described in embodiments 1 to 7 wherein said set of chillers comprises at least one electrically powered chiller.
9) A cooling system as described in embodiments 1 to 8 wherein said solar vapour absorption machine (3) is placed in a series configuration with said set of chillers (6) which are placed in a parallel configuration with each other.
While the above description contains much specificity, these should not be construed as limitation in the scope of the invention, but rather as an exemplification of the preferred embodiments thereof. It must be realized that modifications and variations are possible based on the disclosure given above without departing from the spirit and scope of the invention. Accordingly, the scope of the invention should be determined not by the embodiments illustrated, but by the appended claims and their legal equivalents.

We claim:
1) A system of cooling paint used in the industrial painting processes, said system comprising at least one solar concentrator, a set of solar collectors, a solar vapour absorption machine, a set of heat exchangers, a set of chillers, and a cooling tower, characterized in that the heat energy tapped from the sun by said solar concentrators and solar collectors is used to operate the solar vapour absorption machine, and chillers are used to supply chilled fluid to heat exchangers which cool the paints, heat exchangers are connected to said solar vapour absorption machine, which in turn is connected to said cooling tower to which said chillers are also connected.
2) A system of cooling paint as claimed in claim 1, wherein a first loop (8) is formed between the paint tanks containing said paint, and said set of heat exchangers, said first loop being an open loop which is formed with a first piping network between said paint tanks and said set of heat exchangers, said paint tanks being a part of said first loop.
3) A system of cooling paint as claimed in claims 1 and 2, wherein a sixth loop is formed between said set of heat exchangers and the first evaporator of said solar vapour absorption machine; said first evaporator and the second evaporators of said set of chillers; and said second evaporators and

said heat exchangers; said sixth loop being a closed loop formed using a second piping network.
4) A system of cooling paints as claimed in claims 1 to 3, wherein a fourth
loop is formed between said set of solar collectors, and a generator section
provided in said solar vapour absorption machine, said fourth loop being a
closed loop and formed using a third piping network.
5) A system of cooling paints as claimed in claims 1 to 4, wherein a fifth loop is formed between a first condenser which is a part of said solar vapour absorption machine, said cooling tower, and the second condensers that form a part of respective said chillers, said fifth loop being a open loop formed by a fourth piping network and the said cooling tower.
6) A system of cooling paints as claimed in claims 1 to 5 wherein the solar heat is concentrated on said set of solar collectors said solar reflectors and collected heat is transferred to said generator section of SVAM through hot water via said fourth loop.
7) A system of cooling paints as claimed in claims 1 to 6, wherein said solar vapour absorption machine cools the water received into said first evaporator before sending it on to said set of second evaporators wherein

water is further cooled before it is sent to said set of heat exchangers for the purpose of cooling paint.
8) A cooling system as claimed in claims 1 to 7 wherein said set of chillers comprises at least one electrically powered chiller.
9) A cooling system as claimed in claims 1 to 8 wherein said solar vapour absorption machine is placed in a series configuration with said set of chillers which are placed in a parallel configuration with each other.