FORM -2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE
Specification
(See Section 10; rule 13)
HYDROGEN ABSORBING,/DESORBING ALLOY BASED AIR CONDITIONER AND HEAT PUMP
THERMAX LIMITED
an Indian Company
of D-13, MIDC Industrial Area, R.D. Aga Road, Chinchwad,
Pune - 411019, Maharashtra, India.
NAME OF THE INVENTORS
1.NAVALE DEVADATTA
The following specification particularly describes the invention and the manner
in which it is to be performed.

FIELD OF THE DISCLOSURE
The present disclosure generally relates to hydrogen absorbing/ desorbing alloy based air conditioner and heat pump.
Particularly, the present disclosure relates to a combined direct and indirect cycle for hydrogen absorbing/ desorbing alloy based air conditioner and heat pump.
BACKGROUND
A metal hydride based system is widely used as an energy efficient substitute for a vapor absorption/compression machine for providing heating, air conditioning, refrigeration, and other heat transfer applications. In this type of system, hydrogen is used as the working fluid. The hydrogen reacts with metals to form metal hydrides, a reaction that is reversible depending upon the temperature and pressure. The metal hydride technology is gaining preference due to its compactness and higher performance with low energy consumption. The metal hydride based system uses the energy associated with the hydrogen and metal reaction to perform heating and cooling, and thereby consumes little energy. Furthermore, the metal hydrides can store thermal energy without any insulation. Metal hydride based systems can be used to provide: air conditioning or heating, preheating the engine on start-up, cooling the electronic components and cooling the engine inlet air. The source of energy can be hot exhaust gases, engine exhaust manifold or engine coolant. The air conditioning systems for vehicular applications known in the prior art have several drawbacks associated there-with, for example, the conventionally known air conditioning systems for vehicular applications have to be disposed near specific locations in the vehicle.

Further, the conventional air conditioning systems for vehicular applications require plurality of dampers for handling air used as the heat transfer fluid, however, such dampers are bulky, thereby increasing the overall size and reducing the energy efficiency of the air conditioning system. Further, one of the reasons for the limited use of metal hydride bjised air conditioners and heat pumps, is the low efficiency of the metal hydride systems as compared to vapor absorption/compression machines.
Accordingly, there is a need for an air conditioning system, particularly, for vehicular applications that can be placed anywhere within the vehicle. Further, there is a need for an air conditioning system for vehicular applications that has compact configuration and is energy efficient.
OBJECTS
Some of the objects of the system of the present disclosure, which at least one embodiment herein satisfies, are as follows:
It is an object of the system of the present disclosure to ameliorate one or more problems of the prior art or to at least provide a useful alternative. An object of the present invention is to provide Hydrogen absorbing/ desorbing alloy based, particularly, a metal hydride based air conditioner and heat pump that can be placed anywhere within the vehicle or at any available space within the vehicle, while still conveniently achieving integration of the air conditioning system with the exhaust system of the vehicle.
Another object of the present disclosure is to provide a-Hydrogen absorbing/ desorbing alloy based, particularly, a metal hydride based air conditioner and

heat pump suitable for mobile air conditioning applications and having a higher efficiency and compact-size with lower power consumption.
Yet another object of the present disclosure is to provide a metal hydride based system for cooling and heating which combines a direct and an indirect cycle.
Other objects and advantages of the system of the present disclosure will be more apparent from the following description when read in conjunction with the accompanying figures, which are not intended to limit the scope of the present disclosure.
SUMMARY
In accordance with one aspect of the present disclosure, a hydrogen absorbing/ desorbing alloy based air conditioner/ heat pump system is disclosed. The air conditioner/ heat pump system includes a pair of high temperature regenerating alloy reactors, a pair of low temperature refrigerating alloy reactors and a pair of heat exchangers. The pair of high temperature regenerating alloy reactors facilitates adsorption and desorption of hydrogen by means of regenerating alloy contained therein, wherein a first of the pair of high temperature regenerating alloy reactors cyclically receives exhaust gases for increasing temperature and pressure of the regenerating alloy housed therein and causes desorption of hydrogen from the regenerating alloy, and wherein a second of the pair of high temperature regenerating alloy reactors cyclically receives atmospheric air. The pair of low temperature refrigerating alloy reactors are functionally connected to the pair of high temperature regenerating alloy reactors and facilitate adsorption and desorption of hydrogen by means of refrigerating alloy contained therein, wherein a first of the pair of low temperature refrigerating alloy reactors is functionally

connected to the first high temperature regenerating alloy reactor and absorbs the hydrogen desorbed from the first high temperature regenerating alloy reactor and the heat liberated during the absorption process is transferred to a heat transfer fluid, thereby increasing temperature of the heat transfer fluid, and wherein a . second of the pair of low temperature refrigerating alloy reactors cyclically desorbs hydrogen therefrom and the desorbed hydrogen is absorbed by the second high temperature refrigerating alloy reactors. The pair of heat exchangers are functionally connected to the pair of low temperature refrigerating alloy reactors, wherein a first heat exchanger of the pair of heat exchangers receives the heat transfer fluid heated in the first low temperature refrigerating alloy heat exchanger and partially cools the heat transfer fluid, and a second heat exchanger of the pair of heat exchangers is functionally connected to the second low temperature refrigerating alloy reactor and receives further cooled heat transfer fluid from the second low temperature refrigerating alloy reactor, wherein the further cooled heat transfer fluid absorbs heat from the air conditioning load. The hydrogen absorbing / desorbing alloy based air conditioner/ heat pump system further include a diverting mechanism for selectively diverting flow of air and exhaust gas to respective high temperature regenerating alloy reactors.
Generally, the hydrogen absorbing/ desorbing alloy based air conditioner/ heat pump system based air conditioner/ heat pump system may further include a pair of pumps, wherein a first pump, pumps heat transfer fluid from the first low temperature refrigerating alloy reactor to the first heat exchanger and a second pump, pumps further cooled heat transfer fluid to the second heat exchanger.
Typically, the pumps are centrifugal pumps or positive displacement pumps.

In accordance with one embodiment, the hydrogen absorbing/ desorbing alloy based air conditioner/ heat pump system based air conditioner/ heat pump system further includes a pair of liquid valves to define flow path of the heat transfer fluid to refrigerating alloy side, particularly to either of the refrigerating alloy heat exchangers.
Typically, the heat exchangers are finned type heat exchangers.
The regenerating alloy and the refrigerating alloy may be metal hydrides.
Generally, the heat transfer medium used in the high temperature regenerating alloy heat exchangers is exhaust gas and air.
Typically, the heat transfer medium used in the Tow temperature refrigerating alloy heat exchangers is liquid.
Particularly, the heat transfer medium used in the low temperature refrigerating alloy heat exchangers is water.
Typically, the diverting mechanism utilizes a diverter for selectively facilitating flow of hot exhaust gas to the casing of either of the high temperature/regenerating alloy metal hydride heat exchangers.
Alternatively, the diverting mechanism utilizes a diverter for selectively facilitating flow of ambient air to the casing of either of the high temperature/regenerating alloy metal hydride heat exchangers.
Typically, the second heat exchanger is selectively connected and disconnected with other components of the hydrogen absorbing and desorbing alloy based air

conditioner/ heat pump system by means of at least one liquid flow passage element.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
The metal hydride based air conditioner and heat pump of the present disclosure will now be explained in relation to the non-limiting accompanying drawings, in which:
FIGURE 1 illustrates a schematic of a conventional direct cycle of a metal hydride based air conditioner/heat pump;
FIGURES 2a and 2b illustrate schematics of a conventional indirect cycle of a metal hydride based air conditioner/heat pump; and
FIGURE 3a and FIGURE 3b illustrate schematics of a combined direct and indirect cycle of a metal hydride based air conditioner/heat pump, in accordance with one embodiment of the present disclosure.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The metal hydride based air conditioner and heat pump of the present disclosure will now be described with reference to the accompanying drawings which do not limit the scope and ambit of the disclosure. The description provided is purely by way of example and illustration.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing

techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
The description hereinafter, of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
FIGURE 1 of the accompanying drawings illustrates a conventional metal hydride based system employing a direct cycle; the system is generally referenced by numeral 10. The system 10 uses air as the heat transfer medium during the absorption and desorption of metal hydride. The system 10 comprises two pairs of reactors with different metal hydrides, in this case (12,14) and (16, 18). In the system 10, 12 & 16 and 14 & 18 are coupled on the hydrogen side, shown by D. One of the pair (12 and 16) is at high pressure and the other pair (14 and 18) is at low pressure. The ambient air flow B, return air (E, F) and

exhaust gas A are inputs to the system 10. The cycle is switched between two modules as per the cycle time, as shown in FIGURE 1. This cycle is initiated when the heat source used is exhaust gas.
The drawbacks of the system 10 are as follows: the system 10 requires twelve air switching/diverting mechanisms for the air streams or three 4-way and two position type diverting valves; integration of metal hydride based system with the existing air handling unit required in air conditioning systems is difficult due to many diverting valves operating in cyclic operation; and large amount of auxiliary power is required for the fans due to increased pressure drop in the increased number of diverting valves.
FIGS. 2a and 2b of the accompanying drawings illustrate a conventional metal hydride based system employing an indirect cycle; the system is generally referenced by numeral 20. The system 20 uses liquid as a heat transfer medium during the adsorption as well as desorption of the metal hydrides. The heat added or heat gained by this liquid is transferred to ambient air B, return air and exhaust gas A by a set of heat exchangers (32, 36, 34 &30). The heat transfer liquid / fluid exchanges heat with the metal hydride in the set of heat exchangers (22, 24, 26 and 28). The liquid input is switched between the modules as per cycle time. The different modules are illustrated in FIG. 2a & FIG. 2b. The system 20 requires diverting valves for the liquid, which are much smaller than those used in the system 10. Also, the system 20 can be easily integrated with the existing air handling units of the cooling/air conditioning systems as the cooling output is available in the form of chilled water C. However, the system 20 has the following limitations: integration of the metal hydride based system employing the indirect cycle with exhaust gas as the heat source is difficult as an intermediate heat transfer fluid circuit must be provided

for heat transfer; additional heat recovery heat exchanger is required in this system; additional pump and pumping power for exhaust heat recovery by intermediate heat transfer fluid is required; and additional heat exchanger is required for rejecting heat from high temperature metal hydride alloy to the ambient air.
The above-listed drawbacks of the conventional exhaust based vehicular air conditioning systems are addressed by providing a hydrogen absorbing and desorbing alloy based system in accordance with this disclosure, as illustrated in FIGS. 3a and 3b, which is a combination of the direct and the indirect cycle, for simple integration with the existing air handling unit of air conditioning systems using exhaust gas as a heat source. The system of the present disclosure overcomes the above-listed drawbacks by providing the high temperature metal hydride/regenerating alloy heat exchanger with the exhaust gases directly via a single diverting valve. This arrangement gives the following benefits:
a) due to the use of exhaust gas and ambient air in the high temperature metal hydride/regenerating alloy heat exchanger, additional heat transfer fluid circuit having pumping system and heat exchanger for heat rejection is eliminated;
b) elimination of additional heat exchanger and pumping system saves on the auxiliary power required to run the pumps and fans; and
c) the low temperature metal hydride/refrigeration alloy uses intermediate heat transfer fluid as a heat transfer media, which can be easily integrated with the existing air handling unit required in air conditioning.
The system of the present disclosure is illustrated in FIGS. 3a and 3b, the system is generally referenced by numeral 100. The system 100 comprises: air (B)/ exhaust gas (A) as media for heat transfer with high temperature metal

hydride/regenerating alloy reactor (102 and 104); a diverting mechanism 110 at the inlet of high temperature metal hydride/regenerating alloy heat exchanger (102 and 104) for ambient air (B) and exhaust gas (A); intermediate heat transfer fluid/liquid (D) as heat transfer media for heat transfer with low temperature metal hydride/refrigerating alloy reactor (106 and 108); a first pumping circuit (116) and valve mechanism (112 and 120) for intermediate heat transfer fluid/liquid and heat exchanger (118) for the heat rejection from low temperature metal hydride/refrigerating alloy heat exchanger (106 and 108) to the ambient air (B); a second pumping circuit (114) and valve mechanism (120 and 112) for receiving cooling from low temperature metal hydride/ refrigerating alloy heat exchanger (108 and 106) to the heat transfer fluid /liquid. The system 100 can be used in automobile / mobile air conditioning application.
The system 100 comprises a pair of high temperature/regenerating alloy metal hydride heat exchangers (102 and 104) connected with a pair of low temperature/refrigerating alloy metal hydride heat exchangers (106 and 108), respectively. This connection is only for the hydrogen flow from 102 to 106 and from 108 to 104. The heat exchangers 102 and 104 receive exhaust gases (A) and ambient air (B) via a diverting damper of the diverting mechanism 110 as the heat transfer media. The diverter damper of the diverting mechanism 110 has two inlet connections and two outlet connections for exhaust gas and ambient air streams. The outlet connections of the diverter 110 are connected to the casing;of the high temperature/regenerating alloy metal hydride heat exchangers 102 and 104.
The low temperature/refrigerating alloy metal hydride heat exchangers 106 and 108 are connected to finned heat exchangers 118 and 122 via 4-way actuating valves 112 and 120. The low temperature/refrigerating alloy metal hydride heat

exchangers 106 and 108 uses liquid, particularly, water as the heat transfer medium. Accordingly, the refrigerating alloy side of the hydrogen absorbing and desorbing alloy based air conditioner/ heat pump system utilizes a pair of liquid valves that define flow path of liquid, particularly, water to refrigerating alloy side particularly, to either of the refrigerating alloy heat exchangers. The liquid valves used for handling liquid are lighter, compact and energy efficient compared to dampers used for handling air used as heat transfer fluid used in conventionally known air conditioning systems for vehicular applications. Accordingly, the hydrogen absorbing and desorbing alloy based air conditioner/ heat pump system in accordance with the present disclosure is compact and energy efficient. A pump 114 is provided for circulating the heat transfer fluid/ liquid, which is cooled in the heat exchangers 106 and 108 and gets heated by taking heat from the air conditioning load from heat exchanger 122. The pump 114 is provided for circulating the heat transfer fluid/liquid, which takes heat from the heat exchangers 106 & 108 and rejects it to the ambient air (B) via heat exchanger 118. The operation of the actuating valves 112 and 120 is cyclic and connects the heat exchangers 106 and 108 to the heat exchangers 122 and 118, alternatively. The metal hydride in 102 and 104 is same and is a regenerating alloy/high temperature metal hydride. The metal hydride in 106 and 108 is -a refrigerating alloy/low temperature metal hydride. The operation of system 100 is cyclic and is divided in: a) first half cycle (FIG. 3a); and b) second half cycle (FIG. 3b).
Referring to FIGURE 3a, the diverting -diverter 110 allows hot exhaust gas to flow to the casing of the first high temperature/regenerating alloy metal hydride heat exchanger 102 and over the heat exchanger 102. Simultaneously, the diverter 110 allows ambient air to flow to the casing of second high temperature/regenerating alloy metal hydride heat exchanger 104 and over the

heat exchanger 104. During this cycle, the first low temperature metal hydride heat exchanger 106 is connected to the ambient air heat exchanger 118 and second low temperature metal hydride heat exchanger 108 is connected to the cold air heat exchanger 122 by means of actuating valves 112 and 120. Heat transfer fluid pumped by pump 116 flows through first low temperature metal hydride heat exchanger 106 and air heat exchanger 118 in a closed loop/circuit. Heat transfer fluid pumped by pump 114 flows through second low temperature metal hydride heat exchanger 108 and the cold air heat exchanger 122 in a closed loop/circuit.
Hot exhaust gases (A) heat the first high temperature metal hydride heat exchanger 102 and thereby the outlet temperature of the exhaust gases is reduced. The temperature and pressure of the regenerating alloy / high temp metal hydride of 102 increases due to heat addition from exhaust gases. During this process the first regenerating alloy / high temp metal hydride of 102 desorbs hydrogen. The hydrogen desorbed by the heat exchanger 102 flows to the first refrigerating alloy/low temperature metal hydride heat exchanger 106 via connected hydrogen pipe connection (D). Metal hydride in heat exchanger 106 absorbs hydrogen and heat liberated during absorption is transferred to the heat transfer fluid (C) flowing through tube side of heat exchanger 106. Temperature of the heat transfer fluid (C) increases in this process. Heat added in a heat transfer fluid in heat exchanger 106 is transferred to ambient air in the air heat exchanger 118 resulting in reduced temperature of heat transfer fluid.
In this first half cycle, ambient air (B) flows via the diverter 110 to the second regenerating alloy/high temperature metal hydride heat exchanger 104. The tube side of the second refrigerating alloy /low temperature metal hydride heat exchanger 108 is connected to the cold air heat exchanger 122 by means of

valves 112 and 120. With such configuration, only either of the low temperature metal hydride heat exchanger 108 and 106 is in charging mode at one time, while the other is in discharging mode. Heat transfer fluid that is cooled in the second refrigerating alloy /low temperature metal hydride heat exchanger 108, particularly, the chilled water is pumped from the second low temperature metal hydride heat exchanger 108 to the cold air heat exchanger 122 by pump 114 in a closed loop / circuit. With such a configuration, the Hydrogen absorbing, desorbing alloy based, particularly, a metal hydride based air conditioner and heat pump can be placed anywhere within the vehicle or at any available space within the vehicle, while still conveniently achieving integration of the air conditioning system with the exhaust system of the vehicle.
Heat transfer fluid which is normally maintained at low temperature takes cooling / air-conditioning load from the heat exchanger 122, thereby increasing the temperature of the heat transfer fluid. In the heat exchanger 122, the air is cooled which is used for air conditioning. As the heat transfer fluid with increased temperature passes through the second low temperature metal hydride heat exchanger 108, it gives heat to the refrigerating alloy / low temperature metal hydride in the heat exchanger 108. Due to addition of heat from the heat transfer fluid, metal hydride- in the heat exchanger 108 desorbs hydrogen. During this process the heat transfer fluid gets cooled. The desorbed hydrogen from the heat exchanger 108 flows to the second regenerating alloy/high temperature metal hydride heat exchanger 104 via the hydrogen pipe connection (D). This hydrogen gets absorbed in the regenerating alloy/ high temperature metal hydride in the heat exchanger 104, releasing heat of reaction during absorption process. The ambient air (B) flowing over the heat exchanger 104 takes the heat released during the hydrogen absorption process. During this

process temperature of the ambient air (B) increases and it is released to the atmosphere.
Thus, in first half cycle of operation:
■ the first high temperature metal hydride heat exchanger 102 is in desorption mode using heat from exhaust gases, the desorbed hydrogen is absorbed by the first low temperature metal hydride heat exchanger 106;
■ during desorption in the heat exchanger 102 the exhaust gas temperature is reduced;
■ during absorption in the first low temperature metal hydride heat exchanger 106, heat is transferred to the ambient air (B) via intermediate circuit of heat transfer fluid and air heat exchanger 118;
■ the second low temperature metal hydride heat exchanger 108 is in desorption mode using heat from heat transfer fluid received from heat exchanger 122 via the intermediate circuit, the desorbed hydrogen from heat exchanger 108 is absorbed in the second high temperature metal hydride heat exchanger 104;
■ during desorption in the second low temperature metal hydride heat exchanger 108, the heat transfer fluid get cooled;
■ during absorption in the second high temperature metal hydride heat exchanger 104, heat is transferred to the ambient air (B).
-This operation continues for half cycle time where cooling effect is realized in the second low temperature metal hydride heat exchanger 108. Referring to FIGURE 3b, the diverter 110 allows hot exhaust gases (A) to flow to casing of the second high temperature/regenerating alloy metal hydride heat exchanger 104 and over the heat exchanger 104. Simultaneously, the diverter

110 allows ambient air (B) to flow to the casing of first high temperature/regenerating alloy metal hydride heat exchanger 102 and over the heat exchanger 102. During this second half cycle, the second low temperature metai hydride heat exchanger 108 is connected to the air heat exchanger 118 and the first low temperature metal hydride heat exchanger 106 is connected to the cold air heat exchanger 122 by means of actuating valves 112 & 120. Heat transfer fluid pumped by pump 116 flows through the second low temperature metal hydride heat exchanger 108 and the air heat exchanger 118 in a closed loop / circuit. Heat transfer fluid pumped by pump 114 flows through the first low temperature metal hydride heat exchanger 106 and the cold air Jieat exchanger 122 in a closed loop / circuit.
Hot exhaust gases (A) heat the second high temperature metal hydride heat exchanger 104, the outlet temperature of the exhaust gases (A) is reduced. The temperature and pressure of the regenerating alloy/high temperature metal hydride of the heat exchanger 104 increases due to the heat from the exhaust gas. During this process the regenerating alloy/high temp metal hydride of the heat exchanger 104 desorbs hydrogen. The hydrogen desorbed by the metal hydride in heat exchanger 104 flows to the refrigerating alloy/low temperature metal hydride heat exchanger 108 via connected hydrogen pipe connection (D). Metal hydride in the heat exchanger 108 absorbs the hydrogen and the heat liberated during the absorption process is transferred to the heat transfer fluid (C) flowing through tube side of the heat exchanger 108. Temperature of the heat transfer fluid increases in this process. Heat added in the heat transfer fluid in the heat exchanger 108 is transferred to ambient air in the air heat exchanger 118, thereby reducing the temperature of the heat transfer fluid.

In the second half cycle, ambient air flows via the diverter 110 to the first regenerating alloy / high temperature metal hydride heat exchanger 102. The tube side of the first refrigerating alloy /low temperature metal hydride heat exchanger 106 is connected to the cold air heat exchanger 122 via the valves 112 and 120. Heat transfer fluid is pumped from the first low temperature metal hydride heat exchanger 106 to the cold air heat exchanger 122 by means of
pump 114 in a closed loop / circuit. Heat transfer fluid which is normally
*
maintained at low temperature takes cooling / air conditioning load from the heat exchanger 122, and temperature of heat transfer fluid is raised. In the heat exchanger 122, cold air is produced which is used for air conditioning. As the heat transfer fluid with increased temperature passes though the first low temperature metal hydride heat exchanger 106, it gives heat to the refrigerating alloy / low temperature metal hydride in the heat exchanger 106. Due to addition of heat from heat transfer fluid, the metal hydride in the heat exchanger 106 desorbs hydrogen. During this process the heat transfer fluid gets cooled reducing its temperature. The desorbed hydrogen from the heat exchanger 106 flows to the first high temperature metal hydride heat exchanger 102 via the hydrogen pipe connection (D). This hydrogen gets absorbed in the first regenerating alloy/ high temperature metal hydride in the heat exchanger 102 releasing heat of reaction during absorption process. The ambient air flowing over the heat exchanger 102 takes the heat released during the hydrogen absorption process. During this process temperature of the ambient air increases and it is released to the atmosphere.
Thus, in the second half cycle of operation:
■ the second high temperature metal hydride heat exchanger 104 is in desorption mode using the exhaust heat, and the desorbed hydrogen is

absorbed by the second low temperature metal hydride heat exchanger 108;
■ during desorption in the second high temperature metal hydride heat exchanger 104 the exhaust gas temperature is reduced.
■ during absorption in second low temperature metal hydride heat exchanger 108, the heat is transferred to the ambient air via intermediate circuit of heat transfer fluid and the air heat exchanger 118;
■ the first low temperature metal hydride heat exchanger 106 is in desorption mode using heat from heat transfer fluid received from heat exchanger 122 via the intermediate circuit, the desorbed hydrogen from heat exchanger 106 is absorbed in the first high temperature metal hydride heat exchanger 102;
. ■ during desorption in the first low temperature metal hydride heat exchanger 106, the heat transfer fluid get cooled;
■ during absorption in the first high temperature metal hydride heat
exchanger 102 heat is transferred to the ambient air.
This operation continues for half cycle time where cooling effect is realized in the first low temperature metal hydride heat exchanger 106.
TECHNICAL ADVANCEMENTS AND ECONOMICAL
SIGNIFICANCE
The technical advancements offered by the system of the present disclosure which add to the economic significance of the disclosure include the realization of:
• Hydrogen absorbing/ desorbing alloy based, particularly, a metal hydride based air conditioner and heat pump that con be placed anywhere within

the vehicle or at any available space within the vehicle, while still conveniently achieving integration of the air conditioning system with the exhaust system, for example an exhaust system of a vehicle, for utilizing the exhaust gases for cooling of the coolant used in the air conditioning application;
• Hydrogen absorbing,/desorbing alloy based, air conditioner and heat pump that can be conveniently integrated with the vehicle;
• a combined direct and indirect cycle of a metal hydride based air conditioner/heat pump which has an improved efficiency;
• a combined direct and indirect cycle of a metal hydride based air conditioner/heat pump which has compact-size;
• hydrogen absorbing, desorbing alloy based system for cooling and
+ heating which combines a direct and an indirect cycle; and
• a combined direct and indirect cycle of a metal hydride based air
conditioner/heat pump which results in lower power consumption.
Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The use of the expression "at least" or "at least one" suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment to achieve one or more of the desired objects or results.
Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context

for the disclosure. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.

We Claim:
1. A hydrogen absorbing and desorbing alloy based air conditioner/ heat pump system, said air conditioner/ heat pump system comprising:
• a pair of high temperature regenerating alloy reactors for facilitating adsorption and desorption of hydrogen by means of regenerating alloy contained therein, wherein a first of said pair of high temperature regenerating alloy reactors is cyclically adapted to receive exhaust gases for increasing temperature and pressure of said regenerating alloy housed therein and causing desorption of hydrogen from said regenerating alloy, and wherein a second of said pair of high temperature regenerating alloy reactors is cyclically adapted to receive atmospheric air;
• a pair of low temperature refrigerating alloy reactors functionally connected to said pair of high temperature regenerating alloy reactors and facilitating adsorption and desorption of hydrogen by means of refrigerating alloy contained therein, wherein a first of said pair of low temperature refrigerating alloy reactors is functionally connected to said first high temperature regenerating alloy reactor and adapted to absorb said hydrogen desorbed from said first high temperature regenerating alloy reactor and the heat liberated during said absorption process is transferred to a heat transfer fluid, and wherein a second of said pair of low temperature refrigerating alloy reactors is cyclically adapted to desorb hydrogen therefrom and said desorbed hydrogen is absorbed by said second high temperature refrigerating alloy reactors; and
• a pair of heat exchangers functionally connected to said pair of low temperature refrigerating alloy reactors, wherein a first heat exchanger of said pair of heat exchangers is adapted to receive

said heat transfer fluid heated in said first low temperature refrigerating alloy heat exchanger and partially cools said heat transfer fluid, and a second heat exchanger of said pair of heat exchangers is functionally connected to said second low temperature refrigerating alloy reactor and is adapted to receive further cooled heat transfer fluid from said second low temperature refrigerating alloy reactor, wherein said further cooled heat transfer fluid absorbs heat from the air conditioning load.
2. The hydrogen absorbing and desorbing alloy based air conditioner/ heat pump system as claimed in claim 1 further comprising a diverting mechanism adapted to selectively divert flow of air and exhaust gas to respective high temperature regenerating alloy reactors.
3. The hydrogen absorbing and desorbing alloy based air conditioner/ heat pump system as claimed in claim 1 further comprising a pair of pumps, wherein a first pump, pumps heat transfer fluid from said first low temperature refrigerating alloy reactor to said first heat exchanger and a second pump, pumps further cooled heat transfer fluid to said second heat exchanger.
4. The hydrogen absorbing and desorbing alloy based air conditioner/ heat pump system as claimed in claim 3, wherein said pumps are centrifugal pumps.
5. The hydrogen absorbing and desorbing alloy based air conditioner/ heat pump system as claimed in claim 3, wherein said pumps are positive displacement pumps.

6. The hydrogen absorbing and desorbing alloy based air conditioner/ heat pump system as claimed in claim 1 further comprising a pair of liquid valves adapted to define flow path of said heat transfer fluid to refrigerating alloy side, particularly to either of said refrigerating alloy heat exchangers.
7. The hydrogen absorbing and desorbing alloy based air conditioner/ heat pump system as claimed in claim 1, wherein said heat exchangers are finned type heat exchangers.
8. The hydrogen absorbing and desorbing alloy based air conditioner/ heat pump system as claimed in claim 1, wherein said regenerating alloy and refrigerating alloy are metal hydrides.

9. The hydrogen absorbing and desorbing alloy based air conditioner/ heat pump system as claimed in claim 1, wherein said heat transfer medium used in said high temperature regenerating alloy heat exchangers is exhaust gas and air.
10. The hydrogen absorbing and desorbing alloy based air conditioner/ heat pump system as claimed in claim 1, wherein said heat transfer medium used in said low temperature refrigerating alloy heat exchangers is liquid.
11. The hydrogen absorbing and desorbing alloy based air conditioner/ heat
pump system as claimed in claim 10, wherein said liquid is water.
12.The hydrogen absorbing and desorbing alloy based air conditioner/ heat pump system as claimed in claim 1, wherein said diverting mechanism

utilizes a diverter for selectively facilitating flow of hot exhaust gas to the casing of either of said high temperature/regenerating alloy metal hydride heat exchangers.
13.The hydrogen absorbing and desorbing alloy based air conditioner/ heat pump system as claimed in claim 1, wherein said diverting mechanism utilizes a diverter for selectively facilitating flow of ambient air to the casing of either of said high temperature/regenerating alloy metal hydride heat exchangers.
14.The hydrogen absorbing and desorbing alloy based air conditioner/ heat pump system as claimed in claim 1, wherein said second heat exchanger is selectively connected and disconnected with other components of said hydrogen absorbing and desorbing alloy based air conditioner/ heat pump system by means of at least one liquid flow passage element,