FORM - 2 THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
PROVISIONAL
Specification
(See section 10; rule 13)


CHILLER-HEAT PUMP
THERMAX LIMITED
An Indian Company
of D-13, MIDC Industrial Area, R.D.Aga Road, Chinchwad,
Pune - 19, Maharashtra, India

THE FOLLOWING SPECIFICATION DESCRIBES THE INVENTION


FIELD OF THE INVENTION
The present invention relates to a system for generating hot water.
Further, the present invention also relates to a system for obtaining
refrigeration effect.
BACKGROUD OF THE INVENTION
Heating water is among the high energy consuming processes in industries. In most of the process industries, hot water in the range of 60 - 80 °C is required for heating applications, like paint booth in automobile industry, paper, food industry, hotels, and the like. Industries generally use oil / gas fired generators for generating hot water. The hot water is sent to the application point, loses its heat and is then resent to the hot water generator. These industries also normally require process water cooling. This application would be conventionally catered-to using either a compression chiller or a vapor absorption machine (typically cooling water from 12°C to 7°C).
A vapor absorption machine produces chilled water using heat source such as steam, hot water, gas and oil. Commercially, most of the vapor absorption machines use lithium bromide (Li-Br) - water as the absorbent-refrigerant pair. The vapor absorption machines use non-ozone depleting refrigerants (water) and require much lesser electricity compared to the vapor compression systems. These machines are even more beneficial for industrial applications where waste heat can be used to generate steam/hot water. The vapor absorption machine can also be used for heating applications by passing the hot refrigerant (water) vapors directly from the high temperature generator to the evaporator.
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The need for energy conservation has been highlighted by concerns about the environment, leading to development of energy efficient heating and cooling systems. Increased attention has been directed towards development of cost-effective and efficient heating pumps, that can provide heating and cooling, thus, reduce the energy consumption. As a result, the vapor absorption machines are gaining favor over conventional vapor compression heat pumps in industrial applications as they use little energy and are environmental friendly.
Also, in conventional absorption type heating-cooling equipments, switching between cooling operations and heating operations could be complicated. Plus, additional components like generators, pumps and chillers might be required. This will add to the initial capital investment and maintenance cost in terms heat and electrical input and utilities. Therefore, a suitable system is required that will provide heating and refrigeration at once.
OBJECTS OF THE INVENTION
An object of the present invention is to provide a system for dual purpose applications such as producing hot water and providing refrigeration effect.
Another object of the present invention is to provide a system that substantially reduces the quantity of oil/gas required for generating hot water.
Yet another object of the present invention is to provide a system that is environmentally friendly and substantially reduces carbon dioxide emissions.
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One more object of the present invention is to provide a system that does not require additional electrical or heat input to produce refrigeration effect.
Still one more object of the present invention is to provide a system that reduces the overall initial capital investment.
Yet one more object of the present invention is to provide a system that reduces the scope of utilities used in day-to-day handling operation.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The invention will now be described with reference to the accompanying drawings, in which;
Figure 1 illustrates a schematic diagram of the system that provides chilling and heating in a single vapor absorption machine showing a cycle in which the dilute LiBr solution flows first to the high temperature generator and the hot water first enters the condenser and then the high pressure absorber;
Figure 2 illustrates a schematic diagram of the system that provides chilling and heating in a single vapor absorption machine showing a cycle in which the dilute LiBr solution flows first to the high temperature generator and the hot water first flows to a absorber and then to the condenser;
Figure 3 illustrates a schematic diagram of the system that provides chilling and heating in a single vapor absorption machine showing a cycle in which the dilute LiBr solution first flows to the low temperature generator and the hot water first flows to the condenser and then to the absorber; and
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Figure 4 illustrates a schematic diagram of the system that provides chilling and heating in a single vapor absorption machine showing a cycle in which the dilute LiBr solution first flows to the low temperature generator and the hot water first enters the absorber and then the condenser.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The drawings and the description thereto are merely illustrative and only exemplify the invention and in no way limit the scope thereof.
In accordance with the present invention, FIGURE 1 illustrates the schematic diagram of the system that provides chilling and heating in a single vapor absorption machine showing a cycle in which the dilute LiBr solution flows first to a high temperature generator HTG and the hot water HW first enters a condenser COND and then a high pressure absorber ABSH. In this cycle, a refrigerant sprayed in a low pressure evaporator EVAL extracts heat from chilled water CW flowing in the evaporator tubes (cooling chilled water from 12-7°C) and gets converted into refrigerant vapors. The refrigerant vapors so released are then absorbed in concentrate Lithium Bromide (LiBr) solution which is sprayed in a low pressure absorber ABSL. As a result of this, the concentrate LiBr solution gets diluted.
Due to the absorption of refrigerant vapors in the LiBr solution, heat of dilution is generated. This heat of dilution is removed using cooling water CW fed to the low pressure absorber ABSL. This water leaves the low pressure absorber ABSL and is then fed to the high pressure evaporator
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EVAH tubes. This water is cooled back to its original temperature in the high pressure evaporator EVAH and is available for recirculation to the low pressure absorber ABSL.
The refrigerant leaving the condenser COND, after having passed through a flash heat exchanger FHE, enters the high pressure evaporator EVAH. This refrigerant extracts heat from the cooling water CW in the high pressure evaporator EVAH tubes. The refrigerant vapors released in this evaporator are absorbed in the concentrate LiBr solution sprayed in the high pressure absorber ABSH. It gets diluted and leaves the high pressure absorber ABSH section.
Water at higher temperature (say 60°C) is used as the heat rejecting medium. This water is first fed to the condenser COND. This step ensures lower condensing temperature and thereby lower generator pressure and temperature. The refrigerant leaves the condenser COND and enters the flash heat exchanger FHE. The hot water HW is then fed to the high pressure absorber ABSH for removing the heat of dilution generated due to refrigerant absorption. Hot water HW leaves the high pressure absorber ABSH at ~ 80°C.
Both the dilute solutions leaving the high pressure and the low pressure absorber mix at their outlet and are then passed through a set of heat exchangers HE. A part of this dilute LiBr solution passes through a set of low temperature heat exchangers LTHE. In the first low temperature heat exchanger LTHE 1, the dilute LiBR exchanges heat with the concentrated LiBr solution entering the low pressure absorber ABSL. The solution then
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passes through the second low temperature heat exchanger LTHE 2 where it exchanges heat with a concentrated solution leaving the low temperature generator LTG.
The concentrated solution leaving the low temperature generator LTG after losing heat in the second low temperature heat exchanger LTHE 2 bifurcates into two streams, one entering the high pressure absorber ABSH (for starting the absorbent cycle) and another entering the first low temperature heat exchanger LTHE 1 to reject further heat to dilute the LiBr solution before entering the low pressure absorber low pressure absorber ABSL.
The other part of the dilute LiBr solution absorbs heat in two heat exchangers HE, the flash heat exchanger FHE and a drain heat exchanger DHE. Since the condensate temperature is relatively higher, this refrigerant is cooled in the flash heat exchanger FHE before it enters the high pressure evaporator EVAH. The refrigerant cools down; the LiBr solution in turn gets heated. This LiBr solution is then passed through the drain heat exchanger DHE. In the drain heat exchanger DHE, the LiBr solution exchanges heat with the refrigerant condensate leaving the low temperature generator LTG. The condensate then enters the condenser COND thus helping to reduce the condenser duty.
These heated dilute solutions are then mixed and fed to the high temperature heat exchanger HTHE. In the high temperature heat exchanger HTHE the dilute LiBr solution extracts heat from high temperature intermediate solution leaving the high temperature generator HTG. This heated solution
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leaving the high temperature heat exchanger HTHE is then fed to the high temperature generator HTG. Using direct heat input like steam or fuel firing, the dilute LiBr solution is boiled in the high temperature generator HTG. The solution gets concentrated to an intermediate concentration and is then fed to the low temperature generator LTG via high temperature heat exchanger HTHE.
The vapors released in the high temperature generator HTG act as a heat source for further LiBr concentration in the low temperature generator LTG. The LiBr solution achieves its final concentration in the low temperature generator LTG. This solution is then fed to both the absorbers ABS via the low temperature heat exchangers LTHE as discussed before, to begin a fresh absorption cycle.
The refrigerant vapors released in the low temperature generator LTG pass through the eliminators and are condensed in the condenser COND. The high temperature generator HTG vapors after losing heat in the low temperature generator LTG and the drain heat exchanger DHE get condensed and are fed back to the condenser COND. The condensed refrigerant is first fed to the high pressure evaporator EVAH via flash heat exchanger FHE and then to the low pressure evaporator EVAL, thereby competing the cycle.
If the direct heat input used is steam, the hot water leaving the high pressure absorber ABSH can be further heated to 85°C by recovering heat from steam condensate in a heat reclaimer. The description given above is for cycle in which the dilute LiBr solution would flow first to the high temperature generator HTG. The hot water HW would first enter the
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condenser COND and then the high pressure absorber ABSH. This helps to reduce the generator temperature and pressure.
The various embodiments in the above cycle are envisaged in Figs. 2, 3 and 4.
FIGURE 2 illustrates a schematic diagram of the system that provides chilling and heating in a single vapor absorption machine showing a cycle in which the dilute LiBr solution flows first to the high temperature generator HTG, and the hot water HW first flows to a absorber ABS and then to the condenser COND. This arrangement can be used if the heat source is of high temperature heat content and higher refrigeration capacity requirement is of prime importance.
FIGURE 3 illustrates a schematic diagram of the system that provides chilling and heating in a single vapor absorption machine showing a cycle in which the dilute LiBr solution first flows to the low temperature generator LTG and the hot water HW first flows to the condenser COND and then to the absorber ABS. This arrangement can be used if the hot water inlet HWI temperature itself is relatively high and maintaining low generator temperature and pressure is critical.
FIGURE 4 illustrates a schematic diagram of the system that provides chilling and heating in a single vapor absorption machine showing a cycle in which the dilute LiBr solution first flows to the low temperature generator LTG and the hot water HW first enters the absorber ABS and then the condenser COND. This arrangement can be used when heat source is of relatively lower temperature and higher refrigeration capacity is required.
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Thus, various cycle combinations can be made depending on the final application or customer requirement.
Depending on the cycle used, the heat exchanger positioning might change. But the basic principle of operation and equipments / heat exchangers involved will remain unchanged. All the temperatures mentioned in the cycle description are indicative and may change as per change in process parameters.
TECHNICAL ADVANCEMENTS & ECONOMIC SIGNIFICANCE
A system to provide both chilling and heating effects in a single vapor absorption machine in accordance with the present invention offers several technical advancements including but not limited to the following:
• The system substantially reduced the overall quantity of oil/gas required for generating hot water as compared to a conventional hot water generator.
• The system also substantially reduces the amount of C02 emissions as quantity of fuel firing is reduced, thus environmental friendly.
• The system uses the same machine to produce hot water and generate the refrigeration effect, thus, additional electrical and heat input is not required.
• The system reduces the overall initial capital investment as no separate units are required.
• The system also reduces the scope of utilities used in day-to-day handling operation
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While considerable emphasis has been placed herein on the system of the preferred embodiment, it will be appreciated that many modifications and alterations can be made in the preferred embodiments without departing from the principles of the invention. These and other changes in the preferred embodiment as well as other embodiments of the invention will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.