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  • How to set up a Refrigerant Media File for KULI
    17.05.2019
  • KULI-System

    KULI hvac is an efficient tool to simulate air conditioning (A/C) systems. On the other hand, KULI base allows to calculate refrigerant properties. By default, media data of several widely-used refrigerants are distributed with KULI. However, custom-tailored applications can require additional ones which have not been provided. This manual describes how to set up a new refrigerant media file for KULI using the third-party software ©REFPROP by NIST.

    In the course of electrification, A/C systems get increasingly complex fulfilling new tasks. With the help of KULI hvac, dependencies and interactions between engine compartment flow, engine cooling system and A/C in the vehicle interior can be calculated. KULI base allows requirements-driven pre-selection of refrigerants based on calculation of key properties at given ambient conditions.

    Due to the described recent developments, there is a strong need for non-standard refrigerants or mixtures to be incorporated into KULI as custom-tailored media files. This manual describes in detail how to do so. First it gives general information about the KULI Refrigerant Media File explaining its structure and its content. Next it provides an overview on how to generate the input data for the file. Step-by-step instructions guide the user through the setup using ©REFPROP by NIST. Multiple screenshots illustrate how to select the substance, the reference state, the units and the data ranges in the pressure-enthalpy diagram. Further informative figures display selection of properties, change of property order, calculation of values, and copying of data into the KULI Media File. The latter steps need to be done for the Wet Steam and Vapor/Fluid Areas separately. Helpful tips complement the manual preventing common mistakes and representing the experience of the KULI development team. Last but not least, the KULI Media File needs to be verified; this can be done by KULI MediaX.

    Keywords: reference data, Mollier chart, Mollier diagram, heat pump, phase change, evaporator, evaporate, condenser, condensate

    Usable from release: KULI 8.0-1.04
    Necessary modules: KULI hvac


    Media Template File, 1 KB
    Documentation, 3 MB
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  • KULI / EXCEL - Transient Simulation
    20.07.2017
  • KULI-System

    The COM interface, developed by Microsoft®, provides a standardized interface for programs to communicate with each other. KULI has a set of built-in COM commands, which allow other programs to run and control a KULI simulation. 

    The current example is an Excel sheet which is created for the control and post processing of the time dependent simulation of a cooling system. The certain benefit of this Excel sheet is, that no Visual Basic programming knowledge of the user is required. Input and output parameters of a KULI file can simply be defined in a list, where the parameters can be chosen from an interactive menu. The sheet allows access to standard KULI COM objects but also to components directly via the KULI Direct Access Interface.

    Usable from release: KULI 8.0-1.04
    Necessary modules: KULI advanced + KULI drive


    KULI File, 154 KB
    Documentation, 432 KB
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  • A Simple Transmission Cooling System
    10.06.2014
  • KULI-System

    The gearbox delivers a significant amount of heat to the gearbox oil, depending on the efficiency of the gearbox in the current operating conditions. This model demonstrates how the amount of heat can be calculated and put into the appropriate locations in the circuits.

    The central element is an efficiency map, based on gear, torque, rpm, and temperature. The conversion from mean eff. pressure to torque is included with the help of calculation controllers. The heat of the gearbox is put into a point mass in an oil circuit. The point mass is also connected to another point mass via a heat conduction component with which it is possible to consider the heat transfer to the ambient.

    Usable from release: KULI 8.0-1.04
    Necessary modules: KULI base + KULI drive


    KULI File, 19 KB
    Documentation, 151 KB
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  • Automatic Creation of Radiator Files from Excel
    10.06.2014
  • KULI-System

    The COM interface, developed by Microsoft®, provides a standardized interface for programs to communicate with each other. KULI components has a set of built-in COM commands, which allows external programs to create KULI component files.

    The part of KULI components that allows to save component files is implemented as a dynamic link library (DLL). This KuliCompInterface.dll can be called by any other application that supports COM. The current example is a simple demonstration of the KULI compinterface. An Excel datasheet for KULI input of a radiator component has an integrated button that allows to store the data directly as an *.kulirad-file.

    Usable from release: KULI 8.0-1.04
    Necessary modules: KULI CompInterface + KULI MediaX


    KULI File, 131 KB
    Documentation, 427 KB
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  • Engine Modeled with Point Masses
    10.06.2014
  • KULI-System

    Only transient simulation allows using the full potential of computer aided engineering regarding component sizing & packaging.
    For the simulation of realistic temperature profiles the thermal capacities of the engine should be considered.

    In this example the existing engine component from KULI drive is remodeled using the primitive components point mass and heat conduction. The engine can be modeled as two direct masses and two indirect masses.The direct masses are heated by combustion processes, and exchange heat with each other, the oil and the water circuit respectively, the ambient air and with the indirect masses. The indirect masses exchange heat via conduction with their respective direct mass only.

    Usable from release: KULI 8.0-1.04
    Necessary modules: KULI base + KULI drive


    KULI File, 17 KB
    Documentation, 146 KB
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  • Example of a Hybrid Passenger Car
    10.06.2014
  • KULI-System

    In this example we will investigate, how to model a hybrid passenger car with KULI. We will especially focus on the electric components and their integration into the overall cooling system.

    Focus on

    • Battery model (module level)
    • Module temperatures
    • Coolant temperatures
    • State of charge Simulation
    • Electric motor and power electronics
    • Cooling system integration
    Usable from release: KULI 8.0-1.04
    Necessary modules: KULI base + KULI drive


    KULI File, 111 KB
    Documentation, 3 MB
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  • Thermostat Modelling
    10.06.2014
  • KULI-System

    In the coolant circuit the thermostatic valve is one of the most important control units to maintain the system’s desired set point temperature. Due to its mechanical technology usually the thermostat has some delay in its reaction, which should be considered in transient cycle simulation. This example is based on the tutorial example ExEngine. The major modification is that it includes a more detailed model for the thermostat, placed in the subsystem “Thermostat”.

    The main idea is that a fluid point mass models the wax element including the metal housing of the thermostat. This point mass is responsible for the hysteresis of the thermostat. The mass of the point mass can be adjusted to fit the current application; moreover, also the heat transfer coefficient from the coolant to the mass can be adjusted, even depending on the flow rate. A corresponding characteristic line is prepared (but contains only a single value in this demo example). 

    The temperature of the mass (i.e., of the wax element) is then taken into a characteristic line in which the lift opening (between 0 and 100%) of the thermostat is calculated. Based on this lift opening two fluid resistances are calculated that have opposite behavior: If the temperature is still low, then the resistance of the bypass will be low, the resistance of the exit to the radiator branch will be high. If the temperature is high, then it is vice versa. 

    The example is given for a thermostat working as a branch; the method would work in the same way for a thermostat working as a confluence.

    Usable from release: KULI 8.0-1.04
    Necessary modules: KULI base + KULI drive


    KULI File, 24 KB
    Documentation, 224 KB
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  • Modelling Tanks
    23.05.2014
  • KULI-System

    Charge air cooler tanks may have a big impact on the efficiency of the heat exchangers behind. A simple approach to model those effects in KULI is the use of area resistances to block the air flow in the area where the tanks of the charge air cooler are located.

    The area resistances correspond to the size of the real -life tanks.To consider the high air resistance typically caused by the tanks a high pressure loss coefficient has to be set. To model the local impact regarding the heat exchanger surfaces the area resistances simply can be integrated to the cooling package using the KULI block function.

    Usable from release: KULI 8.0-1.04
    Necessary modules: KULI base


    KULI File, 99 KB
    Documentation, 209 KB
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  • Adding a Heater Matrix to a Cooling System
    23.05.2014
  • KULI-System

    The heater matrix uses coolant to warm the air that enters the passenger cabin. Of course, this can influence the behavior of the complete coolant water circuit. This example illustrates how to add a heater matrix to a System. 

    To take care of an additional heater matrix in an existing KULI cooling system one has to add a radiator component to the KULI system. On the fluid side it is integrated to a normal coolant circuit using branch and confluence components. On the air side it is necessary to use two parallel branches to simulate separate air paths for the engine cooling part and for the HVAC part. The example is based on the basic example “Ex_Fluid.scs” from the KULI installation setup.

    Usable from release: KULI 8.0-1.04
    Necessary modules: KULI base


    Lectures, 197 KB
    Documentation, 189 KB
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  • Advanced Cabin for Cool Load Determination
    23.05.2014
  • KULI-System

    In the passenger compartment typically a certain comfort temperature is demanded. In concept phase where only a few data are available, KULI supports the engineer in finding the required evaporator cool load to achieve the design temperature.

    The current example represents a very basic configuration of an HVAC system. Air duct, blower and evaporator are simply modeled by heat flow sources, temperature- and mass flow targets with input based on rough assumptions. Using this model, the user can optimize the evaporator air outlet temperature such, that the evaporator cool load will lead to the desired cabin temperature.

    Usable from release: KULI 8.0-1.04
    Necessary modules: KULI advanced + KULI hvac + KULI drive


    KULI File, 22 KB
    Documentation, 3 MB
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  • Cabin Cool Down Simulation with Partial Recirculation
    23.05.2014
  • KULI-System

    In the vehicle HVAC system air recirculation mode is used to reach a desired temperature faster and to prevent from bad outdoor smell. On the other hand passenger air quality may suffer from the recirculation. An approach to keep the advantage of recirculation but reduce its disadvantage is the use of mixed air.

    The current example is based on “Ex_AC_cool_down_recirc.scs” from the KULI installation setup. Here, the user can set a proportion of fresh and recirculation air that will blow into the cabin.

    Usable from release: KULI 8.0-1.04
    Necessary modules: KULI base + KULI hvac + KULI drive
    Kuli File

    KULI File, 104 KB
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  • Condenser Testbench Simulation
    23.05.2014
  • KULI-System

    On the standard condenser test bench the refrigerant inlet and outlet conditions are fixed and the refrigerant mass flow is the test result. For plausibility checks or for calibration: The corresponding KULI model allows a virtual reproduction of the test bench situation.

    The refrigerant condition can be defined by inlet-temperature,-pressure and outlet-subcooling value (à CND-Test_VariantEntryTemp.scs). The air inlet condition is fixed, the air flow can be varied to test for different operating points. The condenser test bench is packed to a subsystem and does not require the user’s attention in first instance. Test results like refrigerant mass flow, heat transfer and pressure loss are collected in another subsystem . Variants of the test bench model require inlet superheat instead of inlet temperature or mean pressure instead of inlet pressure as input (à CND-Test_VariantEntrySH.scs, CND-Test_VariantEntrySH(meanPressure).scs).

    Usable from release: KULI 8.0-1.04
    Necessary modules: KULI base + KULI advanced + KULI hvac


    KULI File, 33 KB
    Documentation, 1 MB
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  • Control Strategy for Cabin Air
    23.05.2014
  • KULI-System

    In the passenger compartment typically a certain comfort temperature is demanded. A possible control strategy to reach comfort level is the use of a PID controller.

    The input of the controller is the deviation of the actual temperature to the reference temperature of 22°C. The output value affects e.g. an electro heater with the purpose of minimizing the temperature gap.

    Usable from release: KULI 8.0-1.04
    Necessary modules: KULI base + KULI hvac + KULI drive


    KULI File, 23 KB
    Documentation, 167 KB
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  • Direct CFD Interface
    23.05.2014
  • KULI-System

    In real-life cooling packages there will be an non-uniform air flow distribution on heat exchangers, which can have a big effect on heat transfer rate. Using CFD results with KULI it is possible to consider this uneven air flow on heat exchangers.

    In the KULI direct CFD interface method *.txt-files containing a velocity distribution from CFD calculation and *.txt-files for writing output like a temperature distribution have to be defined. Unlike the standard/variable resistance matrix method, the direct CFD interface does not require the preprocessing step of calculating a matrix of local resistance corrections. Also unlike the two other methods, here the influence of fans or cp-values on the system air flow are neglected, the system airflow is taken directly from the velocities of the CFD input file. The big benefit of this method is, that KULI can be directly integrated in CFD code, e.g. for iterative underhood computation.

    Usable from release: KULI 8.0-1.04
    Necessary modules: KULI base + KULI advanced


    KULI File, 11 KB
    Documentation, 195 KB
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  • Example of a Commercial Truck
    23.05.2014
  • KULI-System

    This example compares the thermal simulation of a truck cooling system and a simple driving simulation. This proceeding allows the evaluation of the coolant temperatures and the determination of the consumption for a defined driving cycle.

    Focus on

     

    • Engine cooling system
    • Electrical water pump
    • Flow control unit
    • Thermostat and fan control

    Other results

     

    • Fuel consumption

    Input Data

     

    • Driving cycle (rpm, torque)
    • Ambient conditions, ...

    Usable from release: KULI 8.0-1.04
    Necessary modules: KULI hvac + KULI drive


    KULI File, 1 MB
    Documentation, 2 MB
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  • Example of an Electric Passenger Car
    23.05.2014
  • KULI-System

    Beside conventional tasks in energy management, KULI software provides excellent opportunities for the simulation of hybrid- and pure electric vehicles.

    This example compares the influence in power consumption of a mid-sized electric car with and without preconditioning (e.g. during a connection with a charger is established).

    Focus on

    • Battery Conditioning System
    • Cabin Conditioning System
    • Power consumption (with / without Preconditioning)

    Other results

    • Battery SOC
    • Temperature distribution in advanced cabin model (2 row, head – torso – legs for driver and passengers)

    Input Data

    • Battery data (capacity, number of cells, cell voltage)
    • State of Charge (SOC)
    • Initial values (cabin temperature, cell temperatures,..)
    • Boundaries: Ambient temperature, solar intensity, ..
    • Driving cycle (rpm , torque)
    Usable from release: KULI 8.0-1.04
    Necessary modules: KULI base + KULI drive


    KULI File, 3 MB
    Documentation, 3 MB
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  • Heat Pump Cycle with Refrigerant R 134a
    23.05.2014
  • KULI-System

    An extended application of the refrigerant cycle is the use as a heat pump, where the evaporator is used as an auxiliary heater. KULI enables to perform quick analysis of heat pump concepts.

    In the corresponding KULI model the real-life evaporator is set up as an KULI condenser-model and vice versa the real-life condenser is set up as an KULI evaporator-model. For investigations in very cold ambient temperatures, where refrigerant low pressure level might fall below ambient pressure an extended media property file of Refrigerant R134a is attached to the example. Sensors and actuators on the inner circuit sheet of KULI allow a good overview on system parameters and results.

    Usable from release: KULI 8.0-1.04
    Necessary modules: KULI hvac


    KULI File, 175 KB
    Documentation, 208 KB
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  • Hot Gas Cycle with Refrigerant CO2
    23.05.2014
  • KULI-System

    Especially in HVAC systems using CO2 as refrigerant the evaporator can be used as an auxiliary heater. This can be implemented by switching of the condenser which leads to a triangular process.  

    In the corresponding KULI model the condenser simply does not exist. For convergence of the calculation model the operation mode “Hot gas cycle mode” has to be activated in the refrigerant circuit definition.

    Usable from release: KULI 8.0-1.04
    Necessary modules: KULI hvac


    KULI File, 31 KB
    Docmentation, 165 KB
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  • KULI / AVL CRUISE – Coupling with Driving Simulation
    23.05.2014
  • KULI-System

    The COM interface, developed by Microsoft®, provides a standardized interface for programs to communicate with each other. KULI has a set of built-in COM commands, which allow other programs to run and control a KULI simulation. 

    The current example is demonstration of KULI integrated in a driving simulation software like AVL CRUISE. Here there focus is on the impact of the A/C compressor driving power on the vehicle performance. This example also can be found in the AVL CRUISE tutorial. The KULI *.scs-file is contained in the folder “userdata”.

    Usable from release: KULI 8.0-1.04
    Necessary modules: KULI advanced + KULI hvac + KULI drive


    KULI File, 158 KB
    Documentation, 222 KB
    Please login for Download.
  • KULI / EXCEL - Change of Files and Other Properties
    23.05.2014
  • KULI-System

    The COM interface, developed by Microsoft®, provides a standardized interface for programs to communicate with each other.

    KULI has a set of built-in COM commands, which allow other programs to run and control a KULI simulation. 

    The current example is a simple demonstration of KULI controlled by Microsoft EXCEL. For a certain cooling system the mechanical fan is varied and its performance regarding mass flow and power demand is output. Input and output parameters in the KULI file are defined by so-called COM objects. 

    The example is based on “ExTruck.scs” from the KULI installation setup.

    Usable from release: KULI 8.0-1.04
    Necessary modules: KULI advanced


    KULI File, 29 KB
    Documentation, 419 KB
    Please login for Download.
  • KULI / EXCEL - Reading Direct Access Information from KULI File
    23.05.2014
  • KULI-System

    The COM interface, developed by Microsoft®, provides a standardized interface for programs to communicate with each other. 

    KULI has a set of built-in COM commands, which allow other programs to run and control a KULI simulation. KULI “Direct Access” allows to set and get component parameters of a cooling system without defining COM-objects in the *.scs-file. Hence, using Direct Access, a KULI file does not have to be prepared to be controlled by external programs but can be accessed directly, “as it is”. For the user this leads to a remarkable advantage regarding set-up time of the KULI cooling system. The current Excel sheet enables to list all accessible components of a defined cooling system. Furthermore, a list of all possible direct access attributes is provided.

    Usable from release: KULI 8.0-1.04
    Necessary modules: KULI advanced


    KULI File, 109 KB
    Documentation, 521 KB
    Please login for Download.
  • KULI / EXCEL – Steady State Simulation
    23.05.2014
  • KULI-System

    The COM interface, developed by Microsoft®, provides a standardized interface for programs to communicate with each other. KULI has a set of built-in COM commands, which allow other programs to run and control a KULI simulation.

    The current example is an Excel sheet which is created for the control and simulation of one steady state operating point of a cooling system. The certain benefit of this Excel sheet is, that no Visual Basic programming knowledge of the user is required. Input and output parameters of a KULI file can simply be defined in a list, where the parameters can be chosen from an interactive menu. The sheet allows access to standard KULI COM objects but also to components directly via the KULI Direct Access interface. If optimization parameters and targets are set in the KULI *.scs-file, one can simply run the optimization from Excel by activation of the “Run Optimization” option.

    Usable from release: KULI 8.0-1.04
    Necessary modules: KULI advanced


    KULI File, 63 KB
    Documentation, 416 KB
    Please login for Download.
  • Optimization on two Targets with two Parameters
    23.05.2014
  • KULI-System

    KULI advanced offers  an optimization toolbox which can be used for  quick parameter variation on one hand, and automatic minimization, maximization or goal seek on the other hand.

    The current example is a cooling system with goal seek on two targets, and two parameters respectively. The speed of the mechanical fan and the heat rejection of the radiator are adjusted to hit the target of a given radiator top hose temperature and a given charge air exit temperature. The cooling system is based on tutorial example ExCar.scs from the KULI Setup.

    Usable from release: KULI 8.0-1.04
    Necessary modules: KULI base + KULI advanced


    KULI File, 104 KB
    Documentation, 177 KB
    Please login for Download.
  • Statistic Monte Carlo Simulation to Evaluate the Influence of Uncertain Input Data
    23.05.2014
  • KULI-System

    KULI advanced offers  an optimization toolbox which can be used for  quick parameter variation on one hand, and automatic minimization, maximization or goal seek on the other hand. Based on those functions it is possible to perform statistical analysis as well. 

    This example shows the application of the Monte Carlo Method in KULI. The basic idea is that some input parameters do have a certain degree of uncertainty. In this example we assume that the charge air temperature has a temperature of 150°C, but we are not sure, so we apply a normal distribution with mean 150°C and a standard deviation of 10 K. Furthermore we assume that the built in resistance has a zeta of 400, again with some uncertainty resulting in a normal distribution with mean 400 and standard deviation of 10. And finally we assume that we don’t really know the exit cp-value; since we can’t even guess a mean value we apply a uniform distribution between -0.4 and -0.2. When we run this model we choose „Monte Carlo Simulation“ with a sample size of e.g. 500. A possible output is mean value and standard deviation of water and charge air temperatures.

    Usable from release: KULI 8.0-1.04
    Necessary modules: KULI advanced


    KULI File, 112 KB
    Documentation, 181 KB
    Please login for Download.
  • Radiator Variation at Constant Pressure Drop
    23.05.2014
  • KULI-System

    KULI advanced offers  an optimization toolbox which can be used for  quick parameter variation on one hand, and automatic minimization, maximization or goal seek on the other hand.

    This example shows how to simulate a component test rig preserving constant air pressure drop. Based on this method you can compare the performance of different radiators taking into account that a radiator with lower pressure drop allows more air flow such that the overall performance might be better than in the case of a radiator with better heat transfer characteristic but higher pressure drop. The optimization target is set to a given pressure difference and the fan rpm is optimized such that the demanded delta p will be achieved. Choose “Parameter Variation” after clicking the Analysis button!

     

     

    Usable from release: KULI 8.0-1.04
    Necessary modules: KULI base + KULI advanced


    KULI File, 51 KB
    Documentation, 181 KB
    Please login for Download.