Method & system to design an optimized and balanced "automotive HVAC module" and unique design data bank for future optimization using the real time design operation technique.
FIELD OF INVENTION:-
The present invention relates generally to the designing method and system of air conditioner module for a climate control system and more specifically to the air conditioning module for a climate control system specifically suited and intended for vehicular applications and wherein the design data generated during the said designing methodology can be utilized to achieve futuristic optimization & performance enhancement abilities through out the product life cycle.
BACKGROUND AND PRIOR ART:-
Thermal management plays an important role in the vehicle design phase as it not only takes care of the comfort level of the occupants but is also necessary to ensure a safe and smooth running of the vehicle prime mover during the vehicle design life cycle. One of the important vehicle sub system directly influenced by the thermal management is the climate control module which maintains a comfortable temperature and humidity level of the vehicle cabin air. This system more popularly known as HVAC module is an integrated assembly conventionally located below the dash board and instrumentation panel. Figure 1 illustrates a schematic diagram of a typical HVAC module particularly for the vehicular applications. Designing of an automotive HVAC module presents multiple challenges and targets before the designer, some of them being the temperature targets, cool down targets, environmental compatibility, functional targets, performance targets, durability targets, size and weight considerations, energy consumption sealing, product cost targets, packaging the product in a given envelope and wide range of operational and environmental conditions to which the vehicle may be exposed to. HVAC design is unique for a given unique vehicle type and so a new concept has to be built for each vehicle type. Figure 2 displays a unique typical pressure zones for a unique typical vehicle and the said zone being a function of the body contour and vehicle speed explains the above quoted inherent design challenge. A brief description of HVAC design process and concerned system method is mentioned below in a chronological manner and is further divided into generation stages as per the HVAC design and functional features. Before we advance to describe the HVAC module prior design method and later to the method and system as established by the present work it will be further appreciated when seen in the light of a general technological advancements in the world of general design engineering and not limited only to the air conditioning design. The most recent trend in designing process (still in the infant stage) is the concept of real time designing technique wherein the real operational conditions are created and the actual sub systems are operated actually to optimize the design and thus leading to a design process. The trial & error reduces to minimum in this design method and almost zero in some cases and hence the no. of iterations is also phenomenally reduced. A brief description of HVAC design process and concerned methodology is mentioned below in a chronological manner and is further divide/ji into three generation
stages as per the design approach. The method & system disclosed in this work claims thereof to be the basis of next level of HVAC designing method and is called here from the 4th generation of automotive HVAC designing. The design features of various generations are described below in a summarized chart and are explained in the coming sections. There is no real type designing method for automotive HVAC and the present invention discloses a method & system for the same and this makes the current work where such an embodiment has been disclosed appreciable and unique.
(Figure Removed)
The first generation of designing was based fundamentally on the Proto fabrication and testing for desired targets. The flow chart given below illustrates the various steps of designing involved.
(Figure Removed)
Typical cycle as described in the flow chart below can be used to understand the basic inherent design problems leading to a vicious cycle which repeats itself making the design cost too high.
(Figure Removed)

The apparent disadvantages and limitations of such a design method are high and unpredictable design and development cost and time, uncertainty in degree of optimization achieved, hit and trial methodology which is against the basic scientific approach.
With advancements in science & technology, computer aided designing and computer aided engineering came into picture laying the foundation of the 2nd generation of HVAC module design process, method and system wherein and the designers were supported by thermal design, kinematics design, Structural design, modeling & simulation, 3-D solid modeling and other related softwares. The trial and error steps and number of iterations reduced phenomenally. HVAC module design advanced to a state in which the cad techniques are frequently incorporated in the development of a new vehicle. CAD is especially beneficial in packaging the various systems incorporated in a vehicle, to maximize the design and functional capabilities of the vehicle system and subsystems. Analysis software is also used during the design and development cycle to ascertain if the proposed design meets the packaging requirements and thus maximizing the design capabilities. Apart from the packaging aspects many of the design linked functional and performance targets can also be simulated using these design software (CAE & CFD) and thus all the designing aspects were addressed in logical manner at a fast pace and thus the design time and design cost reduced dramatically. Some of the related disadvantages and the limitations of this design approach are requirement of a lot of assumptions which tend to deviate the simulation result with the actual However, the 2- D analysis of the proposed design usually requires multiple drawings iterations and 3- D models as per design have to be tested for functional and performance targets making it quite expensive and time taking. Thus, many times hit & trial remains the only way out. The flow chart displayed below illustrates the design method, process and application of 2nd generation of HVAC
(Flow chart Removed)
Further, knowledge based expert system machines came to aid the computer aided designing of generation 2 (giving them a quantum of intelligence) and this lead to the 3rd Generation of HVAC module design and process and as a result the trial and error were further reduced and no. of iterations also reduced more dramatically than before. This generation saw knowledge based expert systems being developed which gave advice to the designer depending upon the specific environmental conditions and the knowledge base built by the previous design mistakes and the rules incorporated in the computer knowledge bank by the human experts. The inherent limitations of 2nd generation designing are present in 3rd generation also but with a phenomenally less severity and less re works during design phase. The flow chart shown below is for a 3rd generation of HVAC design method, process and application.
(Flow chart Removed)

The most recent trend in designing process is the concept of real time designing technique wherein the already existing 3rd generation design tools are also supplemented by the data of actual components working at real operational conditions and thus leading to a design process with almost no assumptions. The trial and error reduces to a minimum in this design method and almost zero in some cases resulting in minimum iterations. The flow chart below shows the various design steps involved.
(Flow chart Removed)
Toshiba filed a design related patent on 30 March 1994 entitled as "System and method for evaluating a work space represented by a three dimensional model" (Patent no. = 5590268) which provides an
evaluation system and a method which suggest a workspace conforming to motions of an operator working in a workspace represented by a 3 D space. Another patent on similar lines is (Patent no. = 6113644) which provides a "method and system which can quickly provide accurate human factors reach studies for a vehicle design while allowing system packaging flexibility" using coordinate logic methodology for economically optimizing the design process. Another aspect of same domain is disclosed in the US patent 08/ 984806, entitled "Method & system for vehicle design using the occupant reach zone" which was patented by "Ford Global technologies" and describes the use of coordinate logic methodology for ergonomically optimizing the design process. However, the current invention is based on a new concept for designing HVAC module which uses computer application only for data management and also has the potential of future performance enhancement.
Another design related work (Patent no. = 6651037) entitled as "Method of optimizing design of an HVAC air-handling assembly for a climate control system on a vehicle" was patented by Visteon global technologies on 10th December 1999. Another patent on similar lines is (patent no 6487525) entitled as "method for designing a HVAC air-handling assembly for a climate control system on a vehicle." A patented example of the early efforts while the technology was drifting from first generation to the second generation is discussed in the (US patent no. 5197666) filed on 2nd January 1992, invented by "Gilbert L. Wedekind" and entitled "Method and apparatus for estimation of thermal parameters for climate control system" where an air conditioning module is controlled by a non-linear empirical model representing the climate control system efficiency and hence helping to design an energy efficient system. US patent no 6209794 describing computer-aided design method for designing a thermal management system of a vehicle patented by Visteon Global Technologies and entitled as "Method for designing a thermal management system for a vehicle" includes the parametric solid model of the interior thermal management system and the external thermal output of the vehicle and then using computer analytical techniques to arrive at some thermal parameters and calculating the remaining parameters which are essential for HVAC module designing and optimization. These patents can be viewed as an extension of the software analysis applications to facilitate design processes. On the contrary, the current invention proposes a new concept for designing HVAC module which does not use any known technique or computer application for thermal designing and also has the potential of future performance enhancement.
An example of a knowledge based technique is disclosed in US patent no. 5799293 "Method for optimizing the design of a product using knowledge based engineering technique" patented by Ford Global Technologies which signifies the advancement of design technique from computer aided engineering and modeling to the age where past knowledge and learning were utilized to make the expert system machines (gives advice to the designer depending upon the specific environmental conditions and the knowledge base built by the previous design mistakes and the rules incorporated in the computer knowledge bank by the human experts). Another US patent no 7,280,990 relating to a "method and system for designing and modeling a product in knowledge based engineering environment" which includes receiving or creating geometry of an object associated with a product. Engineering rules are retrieved that may be associated with the object. The geometry and the engineering rules are
associatively connected to one another such that changes to the geometry are automatically reflected in the engineering rules and changes to the engineering rules are automatically reflected in the geometry. A knowledge feature may be defined for the object with parameters that may place certain constraints on the design of the object and thus ensuring that attempted changes to the geometry or the engineering rules do not violate the constraints placed on the object by the knowledge feature. Yet another work "Publication number GB236557"9 entitled as "method of knowledge based engineering design of an HVAC air-handling assembly for a climate control system on a vehicle" describes a method of knowledge based engineering design of an air-handling assembly for a climate control system on a vehicle is provided that utilizes parametric automated design in light of predetermined design, manufacturing and engineering criteria and allows analysis of an occupant's thermal comfort early in the design process using knowledge-based design rules and parametric constraints. US patent no. 6477518 entitled as "method of knowledge-based engineering cost and weight estimation of an HVAC air-handling assembly for a climate control system on a vehicle" relates a method of knowledge-based engineering cost and weight estimation of an HVAC air-handling assembly for a climate control system on a vehicle and includes the steps of selecting a parametric model of the HVAC air-handling assembly design using a knowledge-based engineering library stored in a memory of a computer system and selecting a component part from the model of the HVAC air-handling assembly. US patent no 6,477,517 entitled as" method of knowledge-based engineering design of an instrument panel for a vehicle" includes the steps of comparing a result of the analysis of the model of the instrument panel to a predetermined criterion from the knowledge-based engineering library, and varying the parameter so that the model of the instrument panel meets the predetermined criteria. The basic designing methodology however still is computer aided engineering techniques supplemented by knowledge machines and thus with reduced no. of iterations but still possessing all the inherent limitations of the computer aided designing.
With all the above discussed restrictions or limitations, it is required to design an optimized and balanced HVAC module based on real time HVAC operation which is utilized to achieve the important HVAC design parameters with unprecedented accuracy and precision. The method and system disclosed in this work claims thereof to be the basis of a next level of HVAC designing methodology and is called here from the 4th generation of automotive HVAC designing. The disclosed method and system of designing an automotive HVAC module possessing futuristic vision capability as described in the present work is a way ahead of the current generation HVAC designing technique using "real time operation technology" for thermal designing and balancing (virtually zero assumptions) and using computer aided engineering only for the packaging problems or to arrive at a rough reference value of an important parameter.
OBJECTS OF THE INVENTION:
I.The principal objective of the present invention is to provide an optimized designing method and system for an air conditioning module specifically suited for the vehicle cabin.
2. Another objective of the present invention is to determine the exact cooling requirement of the vehicle cabin to achieve a desired set of comfort conditions as predefined by the designer.
3. Another objective of the invention is to provide a design method and system to optimize the system requirement of refrigerant charge for the said air conditioning module.
4. Still another objective of the present invention is to provide a method and system for optimizing the power consumption and coefficient of performance of the said air conditioning module.
5. Another object of the present invention is to provide a design method and system to ensure the perfect balancing of components of the said air conditioning module from the system point of view.
6.Another object of the present invention is to provide a design method and system for determining the cooling rate which can be achieved by the said cooling module at an initial design phase and thus a scope of improving the same if required.
7. Another object of the present invention is to ensure that predefined cool down targets are achieved by the said air conditioning module at the design conceptualization phase itself.
8. Another object of the present invention is to provide a design method and system for determining the amount of deterioration the vehicle cabinet has undergone at any time in the future so that the remedial actions can be taken to restore the vehicle heat load which was estimated at the designing phase of the car initially which will further result in increasing the effectiveness of the said air-conditioning module.
9.Another object of the present invention is to provide a design method and system for future optimization of the performance of the said air-conditioning module.
10. Another objective of the present invention is to create a design data bank for every different HVAC type being manufactured which may be looked upon as the DNA of a given HVAC and can also be used for any futuristic performance enhancement of the said air conditioning HVAC module.
11. Yet another object of the present invention is to minimize the HVAC module design and development time frame.
12. Yet another object of the present invention is to minimize the HVAC module design and development cost.
13. Another objective of the present invention is to take into account the effect of thermal bridge formation inside the vehicle cabin environment.
14. Another objective of the present invention is to take into account the effect of thermal stratification of environment of the vehicle cabin.
15. Another object of the present invention is to provide a well defined procedure and methodology for designing the said air conditioning module instead of the prior art designing which was primarily based on the hit and trial method.
16. Another objective of the present invention is to ensure that the HVAC module designed as per the method defined in the invention will satisfy the cooling targets not only at the design operation conditions but also at idling condition.
17. Yet another objective of the present invention is to define a design effectiveness number for HVAC module and then the methodology advances to find this number for the various design methods including the method and technique as disclosed in the present invention.
SUMMARY
A method & system to design an optimized and balanced automotive HVAC module using real time design operation technique comprising a vehicle for which the heating, ventilation and air conditioning (HVAC) module is to be designed and which houses a sensor network of atleast one sensor element 15 to sense the temperature of the cabin air, atleast one sensor element 18 to sense the temperature of the ambient air, air conditioning thermal circuit wherein the thermal circuit comprise of a HVAC proto module housed in a plastic casing of approximately same or slightly lesser size as compared to the available vehicle HVAC packaging space and the module further comprising an evaporator 10, a blower unit 11, atleast one sensor element to sense the blower 19 volume flow rate of air, an expansion valve 14 placed before the evaporator 10, atleast one sensor element 16 to sense the temperature and relative humidity of the air before the evaporator 10, atleast one sensor element 17 to sense the temperature and relative humidity of the air after the evaporator 10, compressor 12, and a condensing unit 13 placed in two different sub chambers inside the main chamber wherein all these components are interlinked thermally with each other via a network of hoses, tubes and connectors. The method & system to design an optimized and balanced automotive HVAC module as described in any of the preceding claims wherein, the AC thermal circuit comprises high capacity air-conditioning loop with two sensors before and after the evaporator to measure dry bulb temperature, wet bulb temperature and relativity humidity of air both before and after the evaporator during the load determining design stage and which may be retained in the designed HVAC for throughout the module life cycle and which may also play a pivotal role in designing of control system for the said vehicle and also for easy futuristic applications. The method & system to design an optimized and balanced automotive HVAC module as described in any of the preceding claims wherein, the complete methodology comprises the steps of simulation of vehicle ambient conditions as per predefined design input data, estimation of the exact cooling requirement of the vehicle cabin as per the user defined set of conditions, determination of the cabin cooling rate and synchronization of the cooling requirement and the target cooling rate (it is possible that despite satisfying the cooling requirement of the cabin the target rate of cooling load is not achieved and this is due to the vehicle body contour which plays an important role in the transient cooling phase), target setting of the quantum of cooling requirement, determination of the component capacity configuration for the desired air-conditioning module based on the above determined cooling requirement, component selection based on the above calculated component capacity, packaging the above selected components in a plastic casing, packaging analysis to match the exterior contour of the said module with the predefined vehicle packaging envelope, component resizing while keeping the same capacity configuration in case of packaging constraint and again doing the packaging study until a final outer skin is achieved which can comfortably be packaged into the space available in the vehicle, system balancing of the said designed cooling module by the optimization of refrigerant quantity and lastly recording and storing all design data of the above disclosed steps for future applications and the performance enhancement of the said module as described and disclosed in the present invention.
The present invention will be better and more pronouncedly appreciated after going through the following drawing details defining and describing the most preferred embodiment of the disclosed design
methodology and system and which is further followed by a detailed elaboration and explanation of the said vehicular HVAC module design aspects. The main applications, outputs of the said applications and achievements of the disclosed invention being to determine the exact cooling requirement of the vehicle cabin, compilation of design data for futuristic performance enhancement of air conditioning module of the said vehicle, component balancing of the said air conditioning module, refrigerant quantity optimization, definition and estimation of design confidence number of the design method of the said air conditioning module of the said vehicle, minimizing the design time and hence the design cost.
BRIEF DESCRIPTION OF THE DRAWINGS:-
It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention
and are therefore not to be considered for limiting of its scope, for the invention may admit to other
equally effective embodiments.
Figure 1 Schematic diagram of a typical automotive HVAC unit.
Figure 2 Unique pressure zones for a unique moving vehicle.
Figure 3 shows the System set up for the disclosed design technology of HVAC.
DETAILED DESCRIPTION OF THE INVENTION:
The heart of the said invention will be better understood and more appreciable after getting an insight into the method, system and the set up apparatus described below to practice the most preferred embodiment of designing an optimized and balanced HVAC module for the air conditioning applications in general and best suited and intended for vehicular applications. The complete methodology comprises the steps of simulation of vehicle ambient conditions as per predefined design input data, estimation of the exact cooling requirement of the vehicle cabin as per the user defined set of conditions, determination of the cabin cooling rate and synchronization of the cooling requirement and the target cooling rate (it is possible that despite satisfying the cooling requirement of the cabin the target rate of cooling load is not achieved and this is due to the vehicle body contour which plays an important role in the transient cooling phase), target setting of the quantum of cooling requirement, determination of the component capacity configuration for the desired air-conditioning module based on the above determined cooling requirement, component selection based on the above calculated component capacity, packaging the above selected components in a plastic casing, packaging analysis to match the exterior contour of the said module with the predefined vehicle packaging envelope, component resizing while keeping the same capacity configuration in case of packaging constraint and again doing the packaging study until a final outer skin is achieved which can comfortably be packaged into the space available in the vehicle, system balancing of the said designed cooling module by the optimization of refrigerant quantity and lastly recording and storing all design data of the above disclosed steps for future applications and the performance enhancement of the said module as described and disclosed in the present invention. This data may be looked upon as the DNA structure of the module for its entire life cycle. Reference can be made to figure 3 which details the methodology set up as per the method described in the present invention.
Step 1) Test chamber preparation:-
At first, a properly equipped test chamber (more commonly called as wind tunnel) is to be selected where the environmental conditions can be simulated as per the design inputs which are user specific. If such a facility is inaccessible, the methodology can also be carried out at a road where the environment conditions are close to our requirement. The said design validation chambers are used extensively in the automotive air conditioning industry for HVAC testing and will not be needed to be developed exclusively for the present invention. The chamber has the provision of adjusting the thermal parameters such as but not limited to the DBT (Dry bulb temperature) of the controlled environment within the chamber, solar load, wind speed of the controlled environment within the chamber, humidity level of the controlled environment within the chamber, vehicle speed simulation mechanism within the chamber. Thus it allows testing the HVAC module under different set of conditions which the vehicle may have to encounter in real life. The said test chamber may have but not be limited to the sub sections such as compressor sub section (to monitor compression process from outside vehicle), condenser sub section (to monitor condensation process from outside the vehicle), blower section (to maintain and sustain a user defined air flow inside the chamber), charging mechanism (to ensure a proper and accurate refrigerant charging from outside the vehicle), sun Load simulator (to maintain and sustain the solar load of chamber), control room (to maintain and sustain the chamber environment) and data storage room (test data monitoring & recording for further analysis). A typical set of conditions for carrying out the present embodiment may be taken as>
a. Chamber environment (Temperature and humidity):- 35 °C to 55 °C / 60% to 80%
b. Solar Load simulation in chamber environment:- 1000 W/m2 to 1400 W/m2
c. Vehicle cabin environment:- 16 °C to 27 °C/30% to 40%
Step 2) Vehicle preparation:-
The vehicle preparation comprise the steps of placing the said vehicle for which air conditioning module is to be designed in the test chamber, estimation of the HVAC packaging envelope provided in the vehicle, fabricating a proto HVAC module within the estimated packaging area, packaging the largest possible packagable size of evaporator assembly and blower only in the said proto module, completing the circuitry of air-conditioning cycle between said air-conditioning proto module with condensing unit and the compressor unit which are placed in their respective sub chambers followed by a general vehicle inspection to ensure all controls, sensors and functions are working properly as in a typical vehicle of that model.
The package dimensions are taken from the rough estimation of HVAC module packaging in the vehicle. Since only one evaporator (10) core is being placed in the said plastic casing, the evaporator (10) core packaged size positioned in the casing is bigger than the final core size which the optimized HVAC has after the final design of the product is achieved according to the present invention. This is so because a complete HVAC unit has all the elements present in a typical HVAC (heater, filter, kinematics levers etc.). The AC thermal circuit comprises an evaporator 10 and a blower unit 11 in a plastic casing, a compressor 12, and a condensing unit 13 placed in two different sub chambers inside the main chamber, an

expansion valve 14 placed before the evaporator 10, at least one sensor element 15 placed on the driver side to sense the temperature of the cabin air, at least one sensor element 16 to sense the temperature and relative humidity of the air before the evaporator 10, at least one sensor element 17 to sense the temperature and relative humidity of the air after the evaporator 10, at least one sensor element 18 to sense the temperature of the ambient air, at least one sensor element 19 to sense the blower volume flow rate of air wherein all these components are interlinked thermally with each other via a network of hoses, tubes and connectors. After ensuring, that all sensors are properly placed and well calibrated, all sensing transducers have proper orientation and are perfectly located to reflect the actual intended readings, doors of the said vehicle are properly closed and all vehicle controls are properly functioning to ensure that working is being done on a typical vehicle sample, the vehicle is kept inside the climate control chamber.
Step3) Determination of cooling wattage requirement at idling
Determination of cooling wattage requirement of vehicle cabin when vehicle is operating at idling comprise of positioning the vehicle in the cabin of vehicle, maintaining the desired operational and environmental characteristics, soaking the vehicle for thermal stabilization, starting the thermal cycle of said air conditioning module after sufficient soaking has been achieved, monitoring the thermal parameters and recording of thermal parameters in analogue or digital form after cooling starts, calculating the vehicle heat load and cool down rate (It is possible that despite satisfying the cooling requirement of the cabin the target rate of cooling is not achieved and this is primarily due to the vehicle body contour, which plays an important role in the transient cooling phase), comparing the said achieved cool down rate with the target cooling rate, repeating the exercise with a different set of air flow and evaporator size and again checking for the cool down rate, concluding the evaporator size and air flow magnitude which satisfies the cooling rate target. Usually this may not take more than three iterations and all of them can be performed and calculated in a single go. After positioning the vehicle inside the said test chamber, air conditioning unit is put off, engine is on and the vehicle is made to operate at idling condition. The vehicle is left for a couple of hours so that the said vehicle is completely soaked and pre determined ambient conditions have been achieved and stabilized inside the chamber. Another objective of allowing this time is to allow for stabilization of heat generation and heat flow rate and hence taking into consideration the effects of thermal bridge formation and thermal stratification if any so that a proper mapping of transient thermal environment can be achieved. After the predefined and monitored soaking time has been achieved, the said AC module and the data logger devices are started to compile the data. A set of data is provided as an example in table 1:- (Table Removed)
Table 1 The value of heat load is calculated by following formula [Q = (hi - h2) x A] where hi is the enthalpy of the air after the evaporator core at the moment when the temperature of the cabin (initially T1) becomes equal to the target temperature (b), h2 is the enthalpy of the air before the evaporator core at the moment when the temperature of the cabin becomes equal to the target temperature. Thus the said cooling module is capable of throwing "Q" amount of heat outside the cabin. So, the value of Q will be the vehicle heat load.
Similarly, rate of cooling is estimated by calculating simple ratio of temperature difference in and out of cabin and the time taken for the stabilization. Mathematically, cooling rate determination formula is [CR = (b - T1) / 60- 0]. This value depends more on the vehicle contour instead of the AC system capacity. If the cooling rate falls less than the target, we move on to repeat the cooling load requirement and the cabin cooling rate with a different set of air flow and evaporator size. We will again have a set of data in tabular form as described in table (Table Removed)
Table 2
As before, (Q' = M - h2 x A' and R' = [(b - T1') 160 - 0]
If the cool down rate of the cabin is still not achieved, we move on to repeat the exercise with a yet another combination of evaporator size and air flow and thus we get a third data set as shown in the table below- (Table Removed)
Table 3 As before, Q" = (hi - h2) x A" and CR" = (b-T1") /60-0
Since the above data is for the same vehicle and under same set of thermal conditions, the heat load of
the vehicle should remain constant in all three cases.
Thus, Q = Q" = Q" = VHL (Vehicle heat load)
We have to choose the combination of evaporator size (capacity) and air flow magnitude of the case as
discussed above where the calculated cool down rate matches or marginally exceeds the target cool
down rate. Thus we arrive finally to a value of
Q1 - Cooling load requirement and R1 - Cool down rate
Step 4) Determination of cooling wattage requirement of vehicle cabin when vehicle is operating
at average design conditions
Determination of cooling wattage requirement of vehicle cabin when vehicle is operating at average
design conditions comprising the steps of stabilizing the vehicle if this step is performed in the succession
of previous step, soaking the vehicle with engine on, air conditioning module off and vehicle running at
design speed, after soaking putting the AC in on condition and monitoring and recording the data as
described in the previous step. This will lead to a new set of values of
Q2 - Cooling load requirement and CR2 - Cool down rate
Step 5) Cooling requirement target setting
Cooling requirement target setting comprises the steps of comparing the value of Q1 and Q2, The higher
of the two values will be taken as the target heat load. Thus, we arrive at a value of Q (Target heat load or
target cooling requirement of the vehicle cabin)
Step 6) Component capacity configuration ofHVAC module:-
Now knowing the thermal performance requirement, evaporator component capacity and desired air flow
rate the remaining thermal parameters of the air conditioning cycle can be calculated after finalizing the
design suction and discharge pressure and the approximated pressure drops for every thermal function of
the cycle (this can be estimated very accurately by the use of design data books of refrigeration and air
conditioning or even by the study of benchmark data of existing systems without a significant error). Thus,
we can arrive at component capacity requirement of all the thermal elements of the air conditioning loop
(condenser, evaporator, expansion valve and compressor)
Step 7) Module designing and packaging:-
Now knowing the thermal performance requirement, and also the exact dimensional details of all thermal components to be used for the given air conditioning module, we can effectively utilize the three dimensional solid modeling design softwares for arriving at optimum HVAC module architecture which packages the components of capacity and size decided in the previous step and is also packagable in the provided vehicle packaging envelope.
In another embodiment, the HVAC components are selected from the component parametric library that may be knowledge based or non knowledge base and a HVAC architecture solid model is selected from the parametric library of the HVAC solid models, and also the vehicle's HVAC packaging envelope solid model is selected from the parametric library of varying solid models of the vehicle region. The selected component parts are placed in the HVAC model (configuration may be varied by changing the linear and angular positions of HVAC components) and the HVAC model is further placed in the vehicle HVAC packaging space model. In case of a non acceptable interference, the method of component selection is repeated from the said parametric library (keeping the component capacity same and varying only the dimensions). This step is repeated till the packaging outer skin of the HVAC having desired capacity components as determined above is successfully packaged into the envelope.
Step 8) HVAC module balancing:-
The design step of HVAC module balancing comprise of designing a proto air conditioning module as per the design concluded in the previous step, maintaining the test chamber environment as per the user defined conditions (similar to the set up as disclosed in the previous step of cooling requirement determination of the said vehicle cabin) with the only change that a separate mechanism comprise where the refrigerant amount can be gradually charged from a chamber located in the vicinity of the vehicle and the said charging mechanism is linked to computing machine and further to a data logger so that a continuous set of readings are taken) of charging the HVAC module is to be done which can be controlled from outside the vehicle and within the chamber from any suitable subsection , vehicle preparation similar to the one described in the previous step of cooling load requirement determination of the said vehicle cabin with the difference that the refrigerant charging is not done initially and the HVAC module proto positioned in the vehicle shall be the said concluded proto as per the previous step , positioning the vehicle in the chamber, soaking the vehicle for 2 to 3 hrs. so that the thermal behavior is stabilized, starting the vehicle engine and air conditioning module while the is vehicle simulated as running at design speed (40 Km/hr to 60 Km/hr), gradually charging the vehicle and monitoring the thermal parameters as they change with the charge addition, plotting a graph between charge magnitude and cooling achieved and finally concluding the optimum charge quantity by selecting the charge quantity corresponding to the peak point of the graph. (Table Removed)
Table 2
A graph is plotted between cooling capacity and the charge quantity. This gives a point of optimized
charge which provides a Optimized point balanced system. Please refer the

typical graph shown below (Figure Removed)
which may be the outcome of the said
methodology. Thus, we conclude the optimum charge quantity by selecting the charge quantity corresponding to the peak point of the graph.
(Flow chart Removed)
Step 9) Defining confidence number and design process rating of current and as disclosed in the present invention:-
Confidence number as interpretated in the present invention is a method to quantify the amount of effectiveness of a particular design method. Confidence number for each designing process is calculated by monitoring the method of designing of each design parameters at each step which will taken together give an idea of how accurate and optimize the design method and process will be. In the case of HVAC designing method, the design steps and the relevance of each step in percentage is taken as illustrated below:-
Confidence number (100 %) = Temperature Target (25%) + Cool Down targets (15%) + Performance targets (15%) + Packaging targets (25%) + Functional targets (15%) + Durability targets (5%). The sub steps of each designing step can be bifurcated as
Temperature Target ► F (Amount of cooling requirement) ►F(Amount of heat addition to cabin) ► F(Factors which add heat amount are heat transfer through engine + solar heat transfer + Equipment load + leakage air load + Occupants Load + Door operation load)
Cool Down targets ► F(Transient response of cooling kinetics) ► F (Depends on body contour, HVAC
mouth positioning, Air Flow distribution, Duct design and a variety of other complex factors most of which
can not be calculated even with a sufficient)
Performance targets = ► F (power consumption, air distribution, air flow quantity, Vibration level and
noise targets)
Packaging Targets ► F (Vehicle space co - ordinates for mounting and positioning HVAC module and
the designed HVAC outer skin space co - ordinates)
Functional targets ► F (Linearity of HVAC functioning + Serviceability ease + Sudden climate change +
Kinematics forces) ► F (Component characteristics, kinematics designing and material properties and in
general overall design aspects)
Durability Targets ► F (component life) ► F (Stress on components working) ► F (depends on
individual component quality level and overall designing)
Tabular representation of the design steps of each generation designing method defines and calculates
the confidence number of each step and a gross confidence number to assess the overall design
capabilities in respective generation stages particularly for the HVAC designing for a vehicular application
as explained in the table below (Table Removed)
Advancement of confidence number from conventional systems &the present invention
Step 10) Data bank generation and methodology for futuristic optimization:-
To ensure the future use of design data, the amount of heat infiltrating into the vehicle at given ambient conditions and other design data are monitored and recorded during the design phase of HVAC module. There are a variety of factors which affect the performance and efficacy of the HVAC functioning both on the vehicle side as well as on the air conditioner module side. Some of the factors contributing to this performance and functional deterioration are down gradation of thickness and the sheet panel insulation amount and related thermal properties, glass panel thickness and related thermal properties, sturdiness of the vehicle, engine heat transfer and many more similar factors which are well understood by the people who are expert in the field.
Data bank generation and methodology for futuristic optimization comprise of the steps of archiving the design data obtained in the design phase so that it may be referred at a later stage of product life cycle, repetition of cooling requirement of the vehicle after a said number (say, 3 years) of years or in case of any specific problem, calculating the vehicle heat load, comparing the load with the initial load as per the design data in he archive, bridging the gap by taking suitable measures such as air flow increase, insulation increase or even component resizing. Most often the air flow rate increase should suffice the purpose. Numerous modifications and adaptations of the system of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the true spirit and scope of this invention.

We Claim:-
1. A method & system to design an optimized and balanced automotive HVAC module using real
time design operation technique comprising a vehicle for which the heating, ventilation and air
conditioning (HVAC) module is to be designed and which houses a sensor network of atleast one
sensor element 15 to sense the temperature of the cabin air, atleast one sensor element 18 to
sense the temperature of the ambient air, air conditioning thermal circuit wherein the thermal
circuit comprise of a HVAC proto module housed in a plastic casing of approximately same or
slightly lesser size as compared to the available vehicle HVAC packaging space and the module
further comprising an evaporator 10, a blower unit 11, atleast one sensor element to sense the
blower 19 volume flow rate of air, an expansion valve 14 placed before the evaporator 10, atleast
one sensor element 16 to sense the temperature and relative humidity of the air before the
evaporator 10, atleast one sensor element 17 to sense the temperature and relative humidity of
the air after the evaporator 10, compressor 12, and a condensing unit 13 placed in two different
sub chambers inside the main chamber wherein all these components are interlinked thermally
with each other via a network of hoses, tubes and connectors.
2. The method & system to design an optimized and balanced automotive HVAC module as
described in any of the preceding claims wherein, the AC thermal circuit comprises high capacity
air-conditioning loop with two sensors before and after the evaporator to measure dry bulb
temperature, wet bulb temperature and relativity humidity of air both before and after the
evaporator during the load determining design stage and which may be retained in the designed
HVAC for throughout the module life cycle and which may also play a pivotal role in designing of
control system for the said vehicle and also for easy futuristic applications.
3. The method & system to design an optimized and balanced automotive HVAC module as
described in any of the preceding claims wherein, the complete methodology comprises the steps
of simulation of vehicle ambient conditions as per predefined design input data, estimation of the
exact cooling requirement of the vehicle cabin as per the user defined set of conditions,
determination of the cabin cooling rate and synchronization of the cooling requirement and the
target cooling rate (it is possible that despite satisfying the cooling requirement of the cabin the
target rate of cooling load is not achieved and this is due to the vehicle body contour which plays
an important role in the transient cooling phase), target setting of the quantum of cooling
requirement, determination of the component capacity configuration for the desired air-
conditioning module based on the above determined cooling requirement, component selection
based on the above calculated component capacity, packaging the above selected components
in a plastic casing, packaging analysis to match the exterior contour of the said module with the
predefined vehicle packaging envelope, component resizing while keeping the same, capacity
configuration in case of packaging constraint and again doing the packaging study until a final outer skin is achieved which can comfortably be packaged into the space available in the vehicle, system balancing of the said designed cooling module by the optimization of refrigerant quantity and lastly recording and storing all design data of the above disclosed steps for future applications and the performance enhancement of the said module as described and disclosed in the present invention.
4. The method & system to design an optimized and balanced automotive HVAC module as described in any of the preceding claims wherein, the vehicle is left for a couple of hours so that the said vehicle is completely soaked and then the actual cooling requirement of the vehicle as per the pre defined user input design conditions is estimated using a unique design concept of "real time operation"
5. The method & system to design an optimized and balanced automotive HVAC module as described in any of the preceding claims wherein the effect of thermal bridge formation is also taken into consideration during load determination as thus the actual heat load value is obtained which further leads to a balanced design.
6. The method & system to design an optimized and balanced automotive HVAC module as described in any of the preceding claims wherein the effect of thermal stratification is also taken into consideration during load determination as thus the actual heat load value is obtained which further leads to a balanced design.
7. The method & system to design an optimized and balanced automotive HVAC module as described in any of the preceding claims wherein the rate of cooling is also determined and matched with target cooling rate and in case of low rate a new cooling load can be decided which will suffice the cooling rate also as per target value.
8. The method & system to design an optimized and balanced automotive HVAC module as described in any of the preceding claims wherein the cooling load and cooling rate are determined at idling operation as well as design condition are taken into consideration. This ensures that the module will give a sustained good performance at varying operational conditions.
9. The method & system to design an optimized and balanced automotive HVAC module as described in any of the preceding claims wherein, a design method and system for the same is disclosed to determine the cooling rate which can be achieved by the said cooling module at an initial design phase and thus a scope of improving the same if required.
10. The method & system to design an optimized and balanced automotive HVAC module as described in any of the preceding claims wherein, the refrigerant amount is gradually charged and all the parameters are monitored through real time operation technique and thus ensuring the optimization of the system requirement of refrigerant charge for the said air conditioning module.
11. The method & system to design an optimized and balanced automotive HVAC module as described in any of the preceding claims wherein, a method is specified of optimizing the power consumption and coefficient of performance of the said air conditioning module.
12. The method & system to design an optimized and balanced automotive HVAC module as described in any of the preceding claims wherein, a design method and system is provided to ensure the perfect balancing of components of the said air conditioning module from the system point of view.
13. The method & system to design an optimized and balanced automotive HVAC module as described in any of the preceding claims wherein, a design system and method is provided with an inherent control system inbuilt with the design methodology.
14. The method & system to design an optimized and balanced automotive HVAC module as described in any of the preceding claims wherein, the system and method provided claims to minimize the HVAC module design and development time frame.
15. The method & system to design an optimized and balanced automotive HVAC module as described in any of the preceding claims wherein, the system and method provided claims to minimize the HVAC module design and development time frame.
16. The method & system to design an optimized and balanced automotive HVAC module as described in any of the preceding claims wherein, a system and method is disclosed to provide a design method and system for future optimization of the performance of the said air-conditioning module.
17. The method & system to design an optimized and balanced automotive HVAC module as described in any of the preceding claims wherein a design method and system for determining the amount of deterioration the vehicle cabinet has undergone at any time in the future so that the remedial actions can be taken to restore the vehicle heat load which was estimated at the designing phase of the car initially which will further result in increasing the effectiveness of the said air-conditioning module.
18. The method & system to design an optimized and balanced automotive HVAC module as described in any of the preceding claims wherein, a design data bank for everv different HVAC
type being manufactured is created and which may be further may be looked upon as the DNA of a given HVAC and can also be used for any futuristic performance enhancement of the said air conditioning HVAC module.
19. The method & system to design an optimized and balanced automotive HVAC module as described in any of the preceding claims wherein a method and system is provided to define a design effectiveness number for HVAC module and then the methodology advances to find this number for the various design methods including the method and technique as disclosed in the present invention.
20. The method & system to design an optimized and balanced automotive HVAC module as described in any of the preceding claims wherein, a method and system is disclosed to provide a well defined procedure and methodology for designing the said air conditioning module instead of the prior art designing which was primarily based on the hit and trial method.