DESC:FORM – 2
THE PATENTS ACT, 1970
(39 of 1970)

COMPLETE SPECIFICATION
(SECTION 10, RULE 13)

“AN IMPROVED DUAL REFRIGERANT EXPANSION SYS-TEMFOR INVERTER TYPE SPLIT AIR CONDITIONER”

JOHNSON CONTROLS-HITACHI AIR CONDITIONING INDIA LIMITED.
A Company Incorporated Under the Indian Companies Act,
Hitachi Complex , Karan Nagar , Kadi
Dist Mehsana – 382727
Gujarat, India.

The following specification particularly describes the invention and the manner in which is to be performed:
FIELD OF THE INVENTION

The present invention relates to an improved dual refrigerant expan-sion system for inverter type split air conditioner equipped with a vari-able speed compressor (single compressor unit connected with one In-door Unit only). More Specifically the present invention pertains an improved dual refrigerant expansion system for Inverter type split air conditioners for full load as well as part load conditions and achieving high performance in terms of cooling capacity, Coefficient of perfor-mance (herein after referred as COP) and reduction in power consump-tion. The improved dual refrigerant expansion system is economical yet efficient, it is simple and the working is efficient & it is all about an improvement without additional cost.
BACKGROUND OF INVENTION
A split-system air conditioner splits the hot side from the cold side of the system. The cold side, consisting of the an indoor unit also called as Evaporator unit, which has the heat exchanger called as Evaporator and a fan for delivering cool air, is generally placed into a room being cooled. The fan blows air through the coil and routes the air through-out the room. The hot side, known as the condensing unit, lives out-side the building. The unit consists of a heat exchanger called as Con-denser, compressor, expansion device & a fan. The fan is to blow air through the coil, along with a weather-resistant compressor and some control logic. Other than the fact that the hot and cold sides are split apart which ensures no internal heat transfer between Evaporator and Condenser to minimize cooling lose.These units (Evaporator unit and condensing unit) are joined by a set of copper tubing known as an “In-terconnecting piping” which transfers refrigerant from one unit to an-other.Generally only one expansion device is used for refrigerant ex-pansion within the refrigeration cycle of air conditioning system. Air conditioning system are classified majorly in 2 sections, fixed speed & Inverter type.An Inverter is used to control the speed of the compressor motor, so as to continuously regulate the temperature by regulating the refrigerant flow throughout the system according to the load in the room/space being cooled. Basically the refrigeration cycle is based up-on Vapor-compression refrigeration or vapor-compression refrigeration system (VCRS).
Vapor-compression refrigeration or vapor-compression refrigeration system (VCRS) in which the refrigerant undergoes phase changes, is one of the many refrigeration cycles and is the most widely used meth-od for air-conditioning of buildings and automobiles. It is also used in domestic and commercial refrigerators, large-scale warehouses for chilled or frozen storage of foods and meats, refrigerated trucks and railroad cars, and a host of other commercial and industrial services. Oil refineries, petrochemical and chemical processing plants, and nat-ural gas processing plants are among the many types of industrial plants that often utilize large vapor-compression refrigeration systems. Refrigeration may be defined as lowering the temperature of an en-closed space by removing heat from that space and transferring it elsewhere. A device that performs this function may also be called an air conditioner, refrigerator, air source heat pump, geothermal heat pump.
In a vapor compression air conditioning cycle; refrigerant expansion process is executed by means of expansion device which are of different types e.g. Capillary, Thermostatic expansion valve, Electronic expan-sion valve etc. (Applicable in cooling type as well as heating type air conditioners).
All Conventional refrigerant expansion system consists of one expan-sion device in the air conditioning cycle (Fig. 1A), before expansionpro-cess, refrigerant passes through compressor in which it is pressurized and its temperature & pressure increases, this pressurized high pres-sure and high temperature refrigerant gas goes through condenser wherein condensation process occurs and refrigerant changes its phase from vapor to liquid, dissipates the heat to outside and refriger-ant temperature comes down as compared to that when it was dis-charged out from the compressor. This medium temperature and high pressure liquid refrigerant now passes through expansion device in which refrigerant expansion occurs and refrigerant temperature and pressure reduces majorly to the minimum level , this is done because the refrigerant goes through a very small port diameter (0.5 ~ 3.0 mm).After Expansion process, refrigerant is fed to evaporator and cycle continues.
Different expansion devices were developed and used for above men-tioned function.
• The capillary tube, is a conventional expansion device; which is a copper tube of very small internal diameter. It is of very long length and it is coiled to several turns so that it would occupy less space.
• A thermostatic expansion valve (TXV) controls the amount of re-frigerant flow into the evaporator thereby controlling the super-heat at the outlet of the evaporator. Flow control of the refriger-ant is accomplished by use of a temperature sensing bulb, filled with a similar gas as in the system that causes the valve to open against the spring pressure in the valve body as the temperature on the bulb increases.
Said refrigerant expansion devices described above have their limita-tion in precise control of refrigerant flow at part heat loads (wherein the spontaneous response is to be executed precisely).
To overcome the limitation of above two, the Electronic Expansion Valve (herein after referred as EEV) was introduced for precise re-sponse/action towards part loads or variable loads in the room being cooled. The EEV operates with a sophisticated technical design. EEVs control the flow of refrigerant entering a direct expansion evaporator. They do this in response to signals sent to them by an electronic con-troller. A small motor is used to open and close the valve port. The mo-tor is called a step or stepper motor. Step motors do not rotate contin-uously. They are controlled by an electronic controller and rotate a fraction of a revolution for each signal sent to them by the electronic controller. The step motor is driven by a gear train, which positions a pin in a port in which refrigerant flows.
Inverter technology is a great innovation in HVAC (Heating Ventilation and Air Conditioning) field which facilitates air conditioner units to work in variable cooling loads in the room being cooled. The refrigera-tion cycle of an inverter air conditioning system than that of conven-tional is different in aspects of internal components used e.g. Com-pressor (DC variable speed); can vary its rotations according to the load present and the mass flow rate can be varied unlike convention system does,Expansion device (Electronic Expansion Valve) used for refrigerant expansion, Variable frequency drive; which is based on microprocessor control system, operates and commands compressor and expansion device to vary mass flow according to the load within the room being cooled. This variable speed compressor can vary its speed from mini-mum to maximum level according to the load variation in the room be-ing cooled likewise the EEV controls refrigerant flow into the system.So as a result of opting inverter technology the system performance is en-hanced and varied according to the load in room being cooled.
As per BEE India (Bureau of Energy Efficiency Govt. of India) Schedule 19,all Inverter Split type Air conditioners must have energy labels on the unit.The purpose of this schedule, the star rating shall be based on Cooling Seasonal Performance Factor (CSPF) as per clause 6.1 of ISO 16358-1: 2013(E). However for the purpose of star labelling, the term Indian Seasonal Energy Efficiency Ratio (ISEER) used instead of CSPF.According to the schedule 19 all Inverter Split type Air condi-tioners must be tested for 100% cooling load and 50% cooling load and the calculation is briefed inISO 16358 Part I: 2013 for calculating ISEER (CSPF) which elaborates “The standard asInternational Organi-zation for Standardization 16358 Part 1 is for Air-cooled air condition-ers and air-to-air heat pumps - Testing and calculating methods for seasonal performance factors: Cooling Seasonal Performance Factor” is applicable to all Split Inverter type air conditioners manufactured in India to classify the Unit performance in terms of BEE’s Star Rating bands. ISEER is Indian Seasonal Energy Efficiency Ratio (Applicable according to BEE Schedule 19A; Prepared for Inverter Split).The same can be accessed;
https://www.beestarlabel.com/Content/Files/Inverter%20AC%20schedule%20final.pdf
While installing an air conditioner the evaporator unit of the air condi-tioner is mounted on the wall of a confined room on a technically ad-vised height (usually bed room, Small office room, cabins etc.) The room must be insulated properly to ensure negligible cooling loss while unit operation in order to save energy consumption, the set tempera-ture is controlled by user from a user friendly remote handset against which unit operates and deliver the cooling according to the load avail-able in the room being cooled. To monitor the compressor operation and speed one room sensor called as thermistor is provided just ex-posed to room air , it is located such that the room air must come di-rectly in contact with this temperature sensor while air movement to the suction area of the Indoor unit. This temperature sensor is con-nected to the controller through electrical connection. The condenser unit is placed outside the room being cooled connected by means of appropriate interconnecting copper pipes of required diameter. The re-frigerant flows from compressor to condenser in the form of high pres-sure and high temperature superheated vapor then it gets converted into high pressure high temperature liquid refrigerant by rejecting the heat of compression and the heat present in the room being cooled. Af-ter leaving from condenser the refrigerant passes through expansion device wherein it expands and gets converted into low temperature and low pressure liquid refrigerant and after expansion device it is fed to evaporator where the refrigerant absorbs the heat from room only and gets converted into low pressure low temperature vapor form and then at the end of refrigeration cycle the refrigerant sucked by the compres-sor and the cycle continues.
The Electrical connections and communication are established be-tween evaporator unit and outdoor unit. When the air conditioner is turned ON; the micro processor based electrical controller starts. It first receives the signal of temperature of hot air from room sensor (thermis-tor) inside the room being cooled; compares it with pre-set value of set temperature for indoor cooling. The electricalcontroller also receives the signal of temperature of ambient air from ambient sensor from outside the room and compares it with pre-set value of set temperature of am-bient air to start cooling operation. Based on the temperature sensed by these two sensors, controller decides the mode of operation and sends signal to indoor unit and outdoor unit.
PRIOR ART
Referring to Fig 1A & 2A; a typical prior art uses a EEV based expan-sion system (1); wherein EEV expansion device (9) is placed between Evaporator unit (13) and condenser unit (5). SaidEEV expansion device (9) controls the refrigerant mass flow required in the room being cooled and regulates it before feeding to evaporator coil (14) as per the given load in Room. EEV (9) is observed to deliver efficient performance at 100% load whereas the efficiency decreases when unit switches to work at part loads as 75%, 50%, 25% load.(Wherein the load; Heating Load present in the Room by any means e.g. human occupancy, elec-tric appliances, Heat radiation through glasses and walls etc.) because the refrigerant mass flow varies in part load as per the requirement al-so according to Load variation Inverter Compressor (2) frequency varies likewise and at that moment refrigerant needs more restriction against its flow in the evaporator coil (14) to control the evaporator (13) and suction line (15) superheat which is managed by EEV (9) (By EEV’s (9) Internal Motor pulses variation) EEV’s (9) pulse variations are defined in the Microprocessor bases electronic controller’s software program which is based on the fuzzy logic of Compressor (2) frequency , Room temperature , Set temperature , Room Air humidity , Outdoor Ambient temperature etc.
Referring to the figure 1A which shows the cycle of flow of refrigerant wherein refrigerant flowsfrom EEV (9) to evaporator coil (14) through liquid service valve (11) passing through expansion outlet line (10) and liquid line (12) wherein EEV (9) expands the liquid refrigerant lowering the pressure and temperature of refrigerant to absorb heat from the room being cooled to deliver cooling solution and comfort to user pre-sent in the room being cooled.After evaporator coil (14) refrigerant is sucked to compressor (2) by suction service valve (16) through suction line (15), compressor (2) compresses the vapor refrigerant and refriger-ant gets pressurized into superheated vapor form; at this time the re-frigerant’s pressure and temperatureare increased.Thereafter, refriger-ant flows to condenser coil (6) by means of discharge line (3) through condenser inlet (4), in condenser coil (6) refrigerant gets condensed by means of rejecting the heat of compression and room heat absorbed while leaving evaporator coil (14) and the temperature of refrigerant re-duces now at the end of cycle it passes through the condenser outlet line (7) and strainer assembly (8)and goes back to EEV (9)for expansion and cycle continues likewise.
In this system (1) EEV (9) is observed to deliver efficient performance at 100% load whereasthe efficiency decreases when unit switches to work at part loadsas 75% , 50% , 25% load.
Analysis for the same was carried out using JCH IN’s (Johnson Con-trols Hitachi air conditioning India limited)one of the Inverter Split air conditioner system considered here is 2.0TR (Ton of refrigeration) with EEV (9) only.
It is observed in the prior art system (1) the actual mass flow rate ob-tained is higher than its requirement to achieve maximum COP when tested for 100% as well as for 50% Load. In a result of which Input power, Discharge pressure obtained higher and Net Refrigeration Effect (herein after referred as NRE) becomes lower in turn COP drops.
Further, certain patent documents disclose the prior art technologies as under:
US 6,581,397 B1, The invention is about air conditioner using R-32 (HFC refrigerant; Low GWP) and also with a bypass circuit to provide another path to facilitate the refrigerant flow except conventional path. The Objective of bypass path is to control and optimize the discharge temperatures as R-32 is the high pressure gas (Pressures are 1.6 times that of R-22).Therefore, it is an object of the present invention to pro-vide a refrigerating device capable of optimizing the discharge tempera-ture of compressor without deteriorating the efficiency of the compres-sor by using a working medium containing an R-32 refrigerant, so that the reliability of the refrigerating device is improved.
It doesn’t have relevance to efficiency improvement in cool mode for variableor part loads.

US 2013/0213078 A1 , The invention is about air conditioner (Cool & Heat Mode) with one outdoor and multiple indoors (having individu-al expansion devices).The function is conventional only the super cool-ing heat exchanger is additionally provided (After Condenser) into the main circuit to sub cool the liquid refrigerant coming from the conden-ser and after this the refrigerant expands in the bypass circuit expan-sion device and flows towards accumulator (Surplus refrigerant collec-tion) having in opposite direction to the main flow.The Nature of flow of the refrigerant in main and bypass circuit is cross. Individual ex-pansion devices are installed in each of the indoors to control the mass flow according to the cooling load for a particular indoor unit. And the surplus refrigerant responsive to a transient operation change (A change in the number of active indoor units.)
No. of Outdoor unit-1, Expansion Device in Outdoor Unit – 1 (in By-pass Path), Indoor Unit – 4, Expansion device in Indoor units (1 per unit), Super Cooling Heat Exchanger-1
It doesn’t have relevance to efficiency improvement in cool mode for variableor part loads.
The study was carried out to understand the unit’s performance in broader aspect to identify the area of improvement:
The terms used in this analysis are as follows with their significance and effect on the air conditioning system:
i) Suction pressure: The refrigerant pressure at suction line where the refrigerant in vapor form is about to be sucked to compressor.
ii) Discharge pressure: The refrigerant pressure at discharge line through which the refrigerant flows to / discharges to the condenser heat exchanger.
iii)Specific volume is defined as the specific weight of the material. Usually expressed in terms of cubic ft. /lb., volume-reciprocal of densi-ty. The specific volume of the refrigerant is the number of cubic feet of gas, which is formed when one pound of refrigerant evaporates. This is an important factor to consider when choosing the size of refrigerators-system components. Vapor produced after vaporization of the liquid at the evaporator coil should occupy minimum volume, to keep pipeline diameter, compressor size, etc. small and compact. Thus refrigerant vapor should have low ‘Specific Volume’.

iv)Enthalpy of refrigerant: Enthalpy is the total amount of heat in unit mass of a substance. Its units are therefore BTU/Lb. The metric coun-terpart is kJ/kg. (Kilo joules/kilogram), it is carried out with the help of refrigerant’s P-H (Pressure-Enthalpy) for different pressures.

v) P-H Chart:Mollier charts are used in designing and analyzing per-formance of vapor compression refrigeration systems. Each refrigerant has its own chart which is a graph of the Enthalpy of a refrigerant dur-ing various pressures and physical states. Mollier charts are also called Pressure-Enthalpy diagrams. Pressure is shown on the vertical axis, enthalpy is on the horizontal axis.

vi) NRE: Net Refrigeration Effect isthe quantity of heat that a unit mass of refrigerant absorbs from the refrigerated space to produce useful cooling. It is the difference between enthalpy of refrigerant vapor leav-ing evaporator and enthalpy of vapor refrigerant entering evaporator in same units. It is carried out with the help of refrigerant’s P-H (Pres-sure-Enthalpy) for different pressures. The higher is the NRE the greater would be the efficiency.

vii)Heat of compression: An amount of enthalpy gain by the refrigerant while compression of refrigerant in compressor, this is equivalent to the heat energy or work done on the refrigerant. Therefore it is the dif-ference between enthalpy of refrigerant vapor leaving the compressor and enthalpy of vapor refrigerant entering compressor in same units. The higher is the heat of compression the lower would be the efficien-cy.

viii)Mass flow rate: The amount of refrigerant per hour to be required to produce the desired cooling effect. The higher the mass flow rate the lower would be the NRE.

ix) Compressor frequency: The compressor frequency refers to be rota-tions per second. The unit is Hz.

The Refrigerant Analysis of the prior art system:
Based on actual unit test results & the obtained value of refrigerant pressures at suction and discharge lines, the refrigerant analysis is carried out referring the P-H Chart. The result shows that refrigerant NRE is yet to be improved also the refrigerant mass flow rate is greater than its requirement.
PARAMETERS UOM @ 100% LOAD @ 50% LOAD
SUCTION PRESSURE
(COMPRESSOR INLET PRESSURE) Kg/Sq. cm 9.8 12.2
PSIG 139.356 173.48
PSIA 154.056 188.18
SPECIFIC VOLUME (Cu Ft/lb.) 0.3892 0.3151
(Cu m/Kg = 0.062428*Cu.ft/lb.) 0.0243 0.0197
ENTHAPLY @ COMPRES-SOR
INLET PRESSURE (BTU/lb.) 122 122.7
(Kcal/kg = 0.556*BTU/lb.) 67.83 68.22
DISCHARGE PRESSURE (COMPRESSOR OUTLET PRESSURE) Kg/Sq. cm 32.2 26.6
PSIG 457.884 378.25
PSIA 472.584 392.95
ENTHAPLY (BTU/lb.) @ COMPRESSOR OUTLET PRESSURE (BTU/lb.) 65.3 58.06
(Kcal/kg = 0.556*BTU/lb.) 36.31 32.28
PARAMETERS UOM @ 100% LOAD @ 50% LOAD
NRE (Kcal/Kg) 31.53 35.94
HEAT OF COMPRESSION (BTU/lb.) 12 9
(Kcal/kg = 0.556*BTU/lb.) 6.67 5
MASS FLOW RATE (Kg/Hr.) 191.85 84.14
REQUIRED
COMPRESSOR FREQUEN-CY REVOLUTIONS PER SECOND 70 25.83
EXPANSION VALVE % OPENING 65% 35%
OPENING
REFRIGERANT --- R-410A R-410A

Table 1: The unit performance mentioned above in which unit’s results are tabulated for 100% load as well as for 50% load. Based on refriger-ant properties i.e. suction pressure, discharge pressure, specific vol-ume, enthalpy etc. in the refrigeration circuit, NRE, heat of compres-sion, mass flow rate are calculated as 31.53 Kcal/Kg., 6.67 Kcal/Kg. & 191.85 Kg. /Hr. respectively @ 100% load and 35.94 Kcal/Kg., 5.00 Kcal/Kg. & 84.14 Kg. /Hr. respectively @ 50% load for the given com-pressor frequency as 70&25.83 for 100% load & 50% load respectively. The expansion valve is best opened at 65% and 35% for 100% load & 50% load respectively.
Analysis shown above is the refrigerant side unit performance which are briefly understood from refrigerant’s Pressure – Enthalpy & Pres-sure – Temperature charts can be accessed from one of the sources;
http://sporlanonline.com/literature/education/5-200.pdf

DISADVANTAGES OF THE PRIOR ART
In Summary,theAir conditioning system of the prior arthas following limitations:
1. The prior art Air conditioner (1) with single expansion system does not work in part load as efficient as it works for 100% load, as no additional control of liquid refrigerant during expansion process is available as a result of which the cooling capacity, Co-efficient of performance (herein after referred as COP) reduces and power consumption gets increased.

2. The prior art Air conditioner (1) with single expansion system possess higher mass flow than the requirement and the unit consumes additional input power as no additional control of liq-uid refrigerant during expansion process is available.

3. The prior art Air conditioner (1) with single expansion system has Electronic expansion valve {herein after referred as EEV (9)}as an expansion mean which cannot be optimized further af-ter reaching a certain level.

4. The prior art Air conditioner (1) with single expansion system has the higher discharge pressure thereby the heat of compres-siongetsincreased; the unit consumesadditionalinput power & overall Net Refrigeration Effect (herein after referred as NRE) drops.

5. The prior art Air conditioner (1) with single expansion system consumes additional input power consumption per hour thereby annual energy consumption is higher which increases the unit running cost.

6. The prior art Air conditioner (1) with single expansion system is optimized in such a way that at a set of compressor (2) frequen-cies and EEV (9) openings in 100% as well as at 50%, the power consumption is higher thereby ISEER gets decreased.

7. The prior art Air conditioner (1) with single expansion system has no additional control of liquid refrigerant during expansion process is available to expand liquid refrigerant in variable loads.

8. The prior art Air conditioner (1) with single expansion system possess the higher supply air temperatures (Grill temperatures) thereby the cooling capacity decreased with the given amount of air flow volume.

9. Therefore there is an unmet need to provide an improved dual re-frigerant expansion system (101) for inverter type split air condi-tioner to enhance the precision of refrigerant expansion of an In-verter type split air conditioner for full load as well as part load conditions and achieving high performance in terms of cooling capacity, COP and reduction in power consumption. When addi-tional parts are incorporated in air conditioner it generally leads to addition of cost and complexity of the air conditioner

OBJECT OF THE INVENTION:
The main objective of the present invention is to provide an improved dual refrigerant expansion system (101) for inverter type split air con-ditionerto enhance the precision of refrigerant expansion of an Inverter type split air conditioner for full load as well as part load conditions and achieving high performance in terms of cooling capacity, COP and reduction in power consumption.
Another objective of the present invention is to provide an improved dual refrigerant expansion system (101) for inverter type split air con-ditionerthat eliminates the problem associated to the single expansion system of excessive mass flow rate and additional input power con-sumption.Being the dual expansion system it facilitates additional ex-pansion process to control liquid refrigerant.
Yet another objective of the present invention is to provide an improved dual refrigerant expansion system (101) for inverter type split air con-ditioner that provides optimum level of expansion control through EEV (9).
Yet another objective of the present invention is to provide an improved dual refrigerant expansion system (101) for inverter type split air con-ditioner that significantly reduces the discharge pressure and heat of compression thereby overall NRE improves.
Yet another objective of the present invention is to provide an improved dual refrigerant expansion system (101) for inverter type split air con-ditioner that substantially reduces power consumption per hour thereby reducing overall annual energy consumption which in turn lowers the running cost.
Yet another objective of the present invention is to provide an improved dual refrigerant expansion system (101) for inverter type split air con-ditioner improves system performance in terms of ISSER keeping com-pressor (2) frequency and EEV opening at optimum level at 100% as well as at 50% load.
Yet another objective of the present invention is to provide an improved dual refrigerant expansion system (101) for inverter type split air con-ditioner that provides provision for additional expansion process to control the refrigerant flow and allow the maximum quantity of refrig-erant pass through said additional expansion provision only.
Yet another objective of the present invention is to provide an improved dual refrigerant expansion system (101) for inverter type split air con-ditioner which is easy to install and set for an optimum efficient sys-tem.
Yet another objective of the present invention is to provide an improved dual refrigerant expansion system (101) for inverter type split air con-ditioner that helps to get the supply air temperatures (Grill tempera-tures) lower to obtain higher cooling capacity with the same amount of air flow volume. This can be understood with the help of psychrometric chart (The part of Psychrometry) which is based on the air physical properties.
Yet another objective of the present invention is to provide an improved dual refrigerant expansion system (101) for inverter type split air con-ditioner is that the improved dual refrigerant expansion system is eco-nomical yet efficient, it is simple and the working is efficient & it is all about an improvement without additional cost.
Psychrometry can be understood and accessed;
http://nptel.ac.in/courses/112105129/pdf/R&AC%20Lecture%2027.pdf
BRIEF DESCRIPTION OF DRAWINGS
Fig.1A: Shows schematic diagram of prior art air conditioning system with EEV expansion system.
Fig.1B:Shows schematic diagram of present invention illustrating air conditioning system with dual expansion system.
Fig.2A: Shows flow diagram of prior art air conditioning system with EEV expansion system.
Fig.2B: Shows flow diagram of present invention illustrating air condi-tioning system with dual expansion system.

Meaning of reference numerals:
101: Dual expansion system
102: Improved air conditioner with improved dual expansion system
103: Secondary expansion device
1: Prior art air conditioning system
2: Compressor
3: Discharge line
4: Condenser Inlet line
5: Condenser unit
6: Condenser Coil
7: Condenser Outlet line
8: Strainer assembly
9: Primary expansion device or EEV(Electronic expansion valve)
10: Liquid Line
11: Liquid service valve
12: Evaporator inlet Line
13: Evaporator unit
14. Evaporator coil
15: Evaporator outlet line
16: Suction service valve
17: Suction line

DETAILED DESCRIPTION OF INVENSION
The embodiment of the present invention is to provide an improved dual refrigerant expansion system for split type inverter air conditioner (101) to enhance the precision of refrigerant expansion of an Inverter type split air conditioner for full load as well as part load conditions and achieving high performance in terms of cooling capacity, COP and reduction in power consumption.
Present improved dual refrigerant expansion system for split type in-verter air conditioner (101) mainly comprising of a secondary ex-pansion device (103) for complementary refrigerant expansion to the refrigerant expansion by existing primary expansion device (9) ena-bling expansion of liquid refrigerant through primary as well as sec-ondary expansion device (9 and 103) simultaneously and for feeding the expanded refrigerant to evaporator coil (14) at the same time keep-ing the compressor (2) frequency and primary expansion device (9) opening in an optimum balance point in a result of which the mass flow rate gets optimized and con-trolled precisely throughout the im-proved air conditioner with improved dual expansion system (102) in 100% as well as in 50% Load and lower to achieve desired ISEER.
Said secondary expansion device (103) is connected to the existing ex-pansion system so as to be placed parallel to the primary expansion device (9). Further, said primary expansion device (9) is preferably EEV and the secondary expansion device (103) is preferably a capillary ex-pansion device.
Wherein further, said primary expansion device is EEV (Electronic Ex-pansion Valve) (9) has a diameter of ? 0.5 ~ 5.0 mm; preferably of ? 1.8 mm bore diameter and secondary expansion device (103) is Capil-lary tube that has a diameter of 0.5 ~ 5.0 mm; preferablyof ? 1.4 mm and of 50 ~ 1000 mm; preferably 530 mm Length. Same can be re-ferred from TIS SPTP-031. Both the devices being parallel to each other to expand the liquid refrigerant at the same time. Working of the same can be referred from figure 1B & 2B.
The Selection of capillary is explained in TIS SPTP-031, wherein the graph is illustrated on the relationship between capillary length & pressure exerted on refrigerant while flowing in the refrigerant cycle of an air conditioning system. The appropriate length required to be for a refrigerant cycle of an air conditioning system shall be selected for a required cooling capacity by means of this standard. While selection all the related parameters i.e. Air flow volume of unit, diameter of cycle tubing pipes, compressor type, refrigerant flow rate etc. must be con-sidered to reach the best optimization.
Referring to the figure 1B & 2B which are showing the cycle of flow of refrigerant wherein refrigerant flows from“Dual expansion system (101)” {which possess the dual and parallel arrangement of two differ-ent means for refrigerant expansion at the same time mainly in-cludes,primary expansion device EEV (9) &Secondary expansion device called as capillary (103)} to evaporator coil (14) through liquid service valve (11) passing through expansion outlet line (10) and liquid line (12) wherein EEV (9) expands the liquid refrigerant lowering the pres-sure and temperature of refrigerant to absorb heat from the room being cooled to deliver cooling solution and comfort to user present in the room being cooled. After evaporator coil (14) refrigerant is sucked to compressor (2) by suction service valve (16) through evaporator outlet line (15) & suction line (17), compressor (2) compresses the vapor re-frigerant and refrigerant gets pressurized into superheated vapor form; at this time the refrigerant’s pressure and temperature are increased. Thereafter, refrigerant flows to condenser coil (6) by means of discharge line (3) through condenser inlet (4), in condenser coil (6) refrigerant gets condensed by means of rejecting the heat of compression and room heat absorbed while leaving evaporator coil (14) and the tempera-ture of refrigerant reduces now at the end of cycle it passes through the condenser outlet line (7) and strainer assembly (8) and goes back to “Dual expansion system (101)”for expansion and cycle continues likewise.
In this system (101), it is observed that system delivers efficient per-formance in terms of NRE & COP also reduction in input power con-sumption at 100% and as well as at 50& load. Which in turn overall Annual energy consumption reduces significantly.
Analysis for the same was carried out using JCH IN’s (Johnson Con-trols Hitachi air conditioning India limited) one of the Inverter Split air conditioner system considered here is 2.0TR (Ton of refrigeration) with “Dual expansion system (101)”.
It is observed in present improved air conditioner with improved dual expansion system (101) the mass flow rate obtained is lower than itwas obtained in air conditioning system based on prior art, the NRE ob-tained is greater than it was obtained in air conditioning system based on prior art, In a result of which Input power, Discharge pressure ob-tained lowerwhich in turn COP & efficiency increased. Overall perfor-mance is improved at 100% as well as at 50% Load.
WORKING OF PRESENT INVENTION
Referring to the figure 1B & 2B which are showing the cycle of flow of refrigerant with inverter type split air conditioner using present im-proved dual refrigerant expansion system (101):
As the air conditioner is turned on; the flow of refrigerant starts from compressor to condenser followed by its flow to present Dual expan-sion system (101). Said dual expansion system (101) receives liquid re-frigerant at high temperature and high pressure from condenser and facilitates the dual flow of refrigerant through said primary and sec-ondary expansion devices of the present dual expansion system. This allows the liquid refrigerant to pass through parallel placed expansion devices so as to enable optimum mass flow control and optimally high expansion of the liquid refrigerant. This is unlike prior existing single or multiple expansion devices that resulted in pressure loss, higher mass flow rate, reduction in refrigerant velocity, additional power con-sumption, higher heat of compression, lower NRE.
As a result; Dual expansion system (101) improves performance and efficiency especially in part loads by optimizing the refrigerant mass flow rate throughout the system. The refrigerant mass flow rate is es-sential factor to work on to achieve best efficiencies. Optimizing the re-frigerant mass flow rate results in reducing the input power consump-tion and annual energy consumption significantly and makes the sys-tem efficient. As this is a variable speed machine so the compressor (2) frequency varies according to the load variation in the room being cooled. Software program Logics are defined for the compressor (2)frequency setting from 13 ~ 126.

COMPARATIVE ANALYSIS OF PRIOR ART AND PRESENT INVEN-TION
When the improved air conditioner with improved dual expansion sys-tem (102) as described herein above is compared with the prior artair conditioning system (1) i.e. the prior arts, the advantages of the im-proved air conditioner with improved dual expansion system (102) are clearly established and the analysis of the comparison is shown herein after in various tables. When the unit performance of the present in-vention (102) is compared with that of the prior art air conditioning system (1); analysis shows 3% ~ 4.5% of cooling capacityimprovement as per the table 2 shown herein below when compared for 100%:

PARAMETERS UOM @ 100 % LOAD
EEV ONLY DUAL EX-PANSION
SUCTION PRESSURE (COMPRESSOR INLET PRESSURE) Kg/Sq. cm 9.8 9.2
PSIG 139.36 130.824
PSIA 154.06 145.524
SPECIFIC VOLUME* (Cu Ft/lb.) 0.3892 0.4127
(Cu m/Kg = 0.062428*Cu.ft/lb.) 0.0243 0.0258
ENTHAPLY @ COM-PRESSOR INLET PRESSURE (BTU/lb.) 122 121.9
(Kcal/kg = 0.556*BTU/lb.) 67.83 67.78
DISCHARGE PRES-SURE (COMPRESSOR OUTLET PRESSURE) Kg/Sq. cm 32.2 31.5
PSIG 457.88 447.93
PSIA 472.58 462.63
ENTHAPLY (BTU/lb.) @ COMPRESSOR OUTLET PRESSURE (BTU/lb.) 65.3 64.35
(Kcal/kg = 0.556*BTU/lb.) 36.31 35.78
NRE* (Kcal/Kg) 31.53 32
HEAT OF COMPRES-SION* (BTU/lb.) 12 11
HEAT OF COMPRES-SION* (Kcal/kg = 0.556*BTU/lb.) 6.67 6.12
MASS FLOW RATE REQUIRED (Kg/Hr.) 191.85 189.01
COMPRESSOR FRE-QUENCY REVOLUTION PER SECOND 70 70
EXPANSION VALVE OPENING % OPENING 65% 35%
AIR SIDE COOLING CAPACITY WATTS 6715.88 6917.38
POWER CONSUMP-TION WATTS 2016.4 1998.5
REFRIGERANT --- R-410A R-410A

* R410A PH & PT charts are referred to obtain the value of NRE, Heat of compression & Specific volume. Can be accessed; http://sporlanonline.com/literature/education/5-200.pdf
Table 2: As the Discharge temperature is reduced from 472.58 to 462.63 PSIA so the heat of compression is also reduced from 6.67 to 6.12 Kcal/Kg(by 8.33%). which in turn the NRE is increased from 31.53 to 32 Kcal/Kg (Improvement of 1.5%). Air side cooling capacity increased from 6715.88 to 6917.38W (Improvement of 3%), & Input power consumption reduced from 2016.4 to 1998.5W (by 1%), Re-quirement of mass Flow rate reduced from 191.85 to 189.01(by 1.48%); When tested for 100% Load.
As stated above NRE improvement is directly proportional to system performance and efficiency improvement, also the reduction in heat of compression & mass flow ratecauses reduction in input power con-sumption which all together improves system ISEER.
When the improved air conditioner with improved dual expansion sys-tem (102) as described herein above is compared with the prior art air conditioning system (1) i.e. the prior arts, the advantages of the im-proved air conditioner with improved dual expansion system (102) are clearly established and the analysis of the comparison is shown herein after in various tables. When the unit performance of the present in-vention (102) is compared with that of the prior art air conditioning system (1); analysis shows 3% ~ 4.5% of cooling capacityimprovement as per the table 3 shown herein below when compared for 50%:

PARAMETERS UOM @ 50 % LOAD
EEV ONLY DUAL EX-PANSION
SUCTION PRESSURE (COMPRESSOR INLET PRESSURE) Kg/Sq. cm 12.2 12.3
PSIG 173.48 174.906
PSIA 188.18 189.606
SPECIFIC VOLUME* (Cu Ft/lb.) 0.3151 0.3126
(Cu m/Kg = 0.062428*Cu.ft/lb.) 0.0197 0.0195
ENTHAPLY @ COM-PRESSOR INLET PRES-SURE (BTU/lb.) 122.7 122.7
(Kcal/kg = 0.556*BTU/lb.) 68.22 68.22
DISCHARGE PRES-SURE (COMPRESSOR OUTLET PRESSURE) Kg/Sq. cm 26.6 26.5
PSIG 378.25 376.83
PSIA 392.95 391.53
ENTHAPLY (BTU/lb.) @ COMPRESSOR OUTLET PRESSURE (BTU/lb.) 58.06 57.92
(Kcal/kg = 0.556*BTU/lb.) 32.28 32.2
NRE* (Kcal/Kg) 35.94 36.02
HEAT OF COMPRES-SION* (BTU/lb.) 9 8.3
HEAT OF COMPRES-SION* (Kcal/kg = 0.556*BTU/lb.) 5 4.61
MASS FLOW RATE REQUIRED (Kg/Hr.) 84.14 83.96
COMPRESSOR FRE-QUENCY REVOLUTION PER SECOND 25.83 25.83
EXPANSION VALVE OPENING % OPENING 35% 2% ~ 20%
AIR SIDE COOLING CAPACITY WATTS 3301.56 3452.29
POWER CONSUMP-TION WATTS 625.3 611.9
REFRIGERANT --- R-410A R-410A

Table 3:As the Discharge temperature is reduced from 392.95 to 391.53 PSIA so the heat of compression is also reduced from 5.0 to 4.61 Kcal/Kg (by 7.78%). which in turn the NRE is increased from 35.94 to 36.02 Kcal/Kg (Improvement of 0.22%). Air side cooling ca-pacity increased from 3301.56 to 3452.29W (Improvement of 4.5%), & Input power consumption reduced from 625.3 to 611.9W (by 2.1%), Requirement of mass Flow rate reduced from 84.14 to 83.96 (by 0.22%); When tested for 50% Load.
Further, as the ambient temperatures vary from place to place and therefore From city to city, comparison and analysis will vary when compare the improved air conditioner with improved dual expansion system (102) than the prior art air conditioning system (1). But the said analysis clearly shows the improvement in cooling capacity and input power saving using the improved air conditioner with improved dual expansion system (102).
This is shown in Table 4:

SUMMARY: TABLE - 4
PARAMETERS UOM @ 100 % LOAD
EEV ONLY DUAL EXPAN-SION
AIR SIDE COOLING CAPACITY WATTS 6715.88 6917.38
POWER CONSUMP-TION WATTS 2016.4 1998.5
COP WATTS / WATTS 3.33 3.46
PARAMETERS UOM 50 % LOAD
EEV ONLY DUAL EXPAN-SION
AIR SIDE COOLING CAPACITY WATTS 3301.56 3452.29
POWER CONSUMP-TION WATTS 625.3 611.9
COP WATTS / WATTS 5.28 5.64
ISEER 4.6 4.84

Table 4: Shows COP improvement from 3.33 to 3.46(by 3.90% at 100% Load),the same from 5.28 to 5.64 (by 6.82% at 50% Load) & ISEER im-provement from 4.60 to 4.84 (by 5.22%).
As the performance of an air conditioner is measured in terms of cool-ing capacity. Cooling capacity further depends upon air enthalpies measured or carried out with respect to supply air temperature (air leaves from indoor unit of an air conditioner) also called as grill tem-perature (as leaves from grill of indoor unit of an air conditioner)and return air temperature (air sucked by indoor unit of an air condition-er). The positive magnitude of the difference between these twois called as air enthalpy difference. As air enthalpy difference rises, cooling ca-pacity increases. The same is derived and calculated with the help of Psychrometric chart. Usually the performance of an air conditioner is carried out in Psychrometric Type Calorimeter Laboratoryatrated conditions (guidelines/norms from BEE INDIA)where all the results are obtained as a test report.
The terms DBT and WBT &Air Enthalpy are as follows:
DBT - The dry-bulb temperature (DBT) is the temperature of air meas-ured by a thermometer freely exposed to the air but shielded from radi-ation and moisture. DBT is the temperature that is usually thought of as air temperature, and it is the true thermodynamic temperature.
WBT - Wet Bulb temperature can be measured by using a thermometer with the bulb wrapped in wet muslin. The adiabatic evaporation of wa-ter from the thermometer bulb and the cooling effect is indicated by a "wet bulb temperature" lower than the "dry bulb temperature" in the air.
Air Enthalpy - The total heat content of the air or enthalpy of air com-prises of the sensible heat and the latent heat. The sensible heat is the heat absorbed or lost during the change in temperature of the air. The latent heat is the heat lost or absorbed during change in phase of the water vapor present in the air. Let us see these heats in more details.
The same is tabulated and compared for the improved air conditioner with improved dual expansion system (102)& the prior art air condi-tioning system (1).

The result is compared for 100% and 50% loads.
ROOM CONDITIONS (ENTERING AIR) TEMPERAURES (DBT / WBT) : 27/19°C
PARAMETERS UOM @ 100 % LOAD
EEV ONLY DUAL EX-PANSION
LEAVING AIR DBT °C 12.91 12.68
LEAVING AIR WBT °C °C 12.27 12.02
AIR ENTHAPLY OF ENTERING AIR KJ/kg 54.1 54.1
AIR ENTHAPLY OF LEAVING AIR KJ/kg 34.8 34.1
AIR ENTHAPLY DIFF. (LEAV.-ENT.) KJ/kg 19.3 20
PARAMETERS UOM 50 % LOAD
EEV ONLY DUAL EXPANSION
LEAVING AIR DBT °C 18.96 18.75
LEAVING AIR WBT °C °C 16.26 15.99
AIR ENTHAPLY OF ENTERING AIR KJ/kg 54.1 54.1
AIR ENTHAPLY OF LEAVING AIR KJ/kg 45.7 44.9
AIR ENTHAPLY DIFF. (LEAV.-ENT.) KJ/kg 8.4 9.2

The capacity tests are carried out at Psychrometeric Calorimeter chamber (@ JCH-IN) Indoor (DBT/WBT; 27°C/19°C) & Outdoor (DBT/WBT; 35°C /24°C).
Table 5: Shows improvement in air enthalpy difference (Entering air enthalpy – Leaving air enthalpy)from 19.3 to 20.0 (by 3.63%) & the same from 8.4 to 9.2(by 9.52%) for 100% and 50% load respectively.As a result of which cooling capacity improved.
Table 6 shows the comparison of ISEER and CSEC (Cooling seasonal energy consumption annual; in kWh) between the improved air condi-tioner with improved dual expansion system (102)& the prior art air conditioning system (1)
Table – 6
EEV ONLY DUAL EXPANSION

Table 6: Shows improvement in ISEERfrom 4.58 to 4.82 (by 5.24%)& CSEC reduced from1135.74 to 1109.88 (by 2.28%).This is the benefit to user.This ISEER table and the whole calculation can be seen at BEE India website schedule 19A (link mentioned on page no.4)for inverter type (variable speed) air conditioners at the 12th page of this document there is a link given to directly download the excel file of the same ap-pearance shown above and after filling the required criteria and values it shows the results / output. The Input required to be filled in the sheet are cooling capacity (Watts) and Input power consumption (Watts) for full capacity (100% load) as well as for half capacity (50% load).
The same can be accessed;
https://www.beestarlabel.com/Content/Files/Inverter%20AC%20schedule%20final.pdf
ADVANTAGES OF THE PRESENT INVENTION
The advantages of the present improved dual refrigerant expansion system (101) for inverter type split air conditioner are:
• It enhances the precision of refrigerant expansion of an Inverter type split air conditioner for full load as well as part load condi-tions and achieving high performance in terms of cooling capaci-ty, COP and reduction in power consumption.
• It eliminates the problem associated to the single expansion sys-tem of excessive mass flow rate and additional input power con-sumption. Being the dual expansion system it facilitates addi-tional expansion process to control liquid refrigerant.
• It provides optimum level of expansion control through EEV (9).
• It significantly reduces the discharge pressure and heat of com-pression thereby overall NRE improves.
• It substantially reduces power consumption per hour thereby reducing overall annual energy consumption which in turn low-ers the running cost.
• It improves system performance in terms of ISSER keeping com-pressor (2) frequency and EEV (9) opening at optimum level at 100% as well as at 50% load.
• It provides provision for additional expansion process to control the refrigerant flow and allow the maximum quantity of refriger-ant pass through said additional expansion provision only.
• It is easy to install and set for an optimum efficient system.
• It helps to get the supply air temperatures (Grill temperatures) lower to obtain higher cooling capacity with the same amount of air flow volume. This can be understood with the help of psy-chrometric chart (The part of Psychrometry) which is based on the air physical properties.
• The improved dual refrigerant expansion system is economical yet efficient, it is simple and the working is efficient & it is all about an improvement without additional cost.

TERMS FURTHER USED IN THIS ART:
• NRE : Net Refrigeration Effect
• EEV : Electronic Expansion Valve
• COP : Coefficient of Performance
• BEE : Bureau of Energy Efficiency
• ISEER : Indian Seasonal Energy Efficiency Ration
• CSEC : Cooling Seasonal Energy Consumption
• TXV : Thermostatic Expansion Valve
• ISO : International Organization for Standardization
• FREQUENCY : Revolutions / Rotations per Seconds
• LCD : Liquid Crystal Display
• PSIG : Pressure in Pounds per Square Inch (Gauge Pressure)
• PSIA : Pressure in Pounds per Square Inch (Absolute Pres-sure)
,CLAIMS:We claim:
1. An improved dual refrigerant expansion system for split type in-verter air conditioner (101) mainly comprising of a secondary ex-pansion device (103) for complementary refrigerant expansion to the refrigerant expansion by existing primary expansion device (9) enabling expansion of liquid refrigerant through primary as well as secondary expansion device (9 and 103) simultaneously and for feeding the expanded refrigerant to evaporator coil (14) at the same time keeping the compressor (2) frequency and primary expansion device (9) opening in an optimum balance point in a result of which the mass flow rate gets optimized and con-trolled precisely throughout the improved air conditioner with improved dual expansion system (102) in 100% as well as in 50% Load and lower to achieve desired ISEER;

wherein said secondary expansion device (103) is connected to the existing expansion system so as to be placed parallel to the primary expansion device (9);

wherein further, said primary expansion device (9) is preferably EEV and the secondary expansion device (103) is preferably a capillary expansion device;

2. An improved dual refrigerant expansion system for split type in-verter air conditioner (101) as claimed in claim 1; wherein said primary expansion device (9)can be of a diameter of ? 0.5 ~ 5 mm and secondary expansion device (103)can be a diameter of 0.5 ~ 5.0 mmand of 50 ~ 1000 mm.”.
Dated this 19th February 2018.

Gopi Trivedi (MS)
Authorized Agent of Applicant

To,
The Controller of Patent
Patent Office
At Mumbai