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    KULI Online library
  • Thermostat
    24.03.2015
  • KULI-System

    Thermostat to control the mass flow through two different branches.

    With the subsystem Thermostat it is possible to control the mass flows through two different branches. Over the temperature of the 1.PM fluid resistances are increased or decrease over 2D curves.
    To adjust the behavior of the thermostat to your own thermostat the following parameters have to be adjusted:

    • Mean thermostatic curve
    • Thermostat opening curve
    • Thermostat closing curve
    • Properties of the Wax element

     

     

     

    Usable from release: KULI 9.1-0.01
    Necessary modules: KULI base + KULI drive


    KULI File, 21 KB
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  • Rankine Circuit (Steam circuit, medium ethanol) of a truck including 2 evaporators (EGR and main exhaust gas evaporator)
    16.03.2015
  • KULI-System

    This example shows how a simple steady states simulation for a steam circuit of a truck – using ethanol as working fluid – can be set up. It consists of the steam circuit itself (closed circuit),  an exhaust gas circuit (as source of the heat) and an open water/glycol circuit which acts as heat sink (condenser). Two evaporators are used as heat sources – one in the EGR system and one in the main exhaust system. 

    The rankine circuit is – similar to the A/C circuit – a thermodynamic cycle. The principle works like this:

    In a first step the feed pump provides the working fluid for the expansion device, whereby the steam valves are used for controlling this system. They can either set the exit temperature at the evaporator or a defined mass flow. In this example two valves are used: One for the exhaust gas recirculation path (EGR path) and one for the main exhaust gas path.

     In a next step the evaporator transfers the energy from the hot exhaust gas to the fluid and changes the medium’s state from liquid to gaseous. This energy is converted in the expansion device (if not bypassed) to mechanical power and cooled down in the condenser (to guarantee a liquid state for the feed pump).

    Usable from release: KULI 10
    Necessary modules: KULI base + KULI ecodrive


    KULI File, 63 KB
    You do not have permission to download this file
  • Rankine Circuit (Steam circuit, medium ethanol) of a truck
    13.03.2015
  • KULI-System

    This example shows how a simple steady states simulation for a steam circuit of a truck – using ethanol as working fluid – can be set up. It consists of the steam circuit itself (closed circuit), an exhaust gas circuit (as source of the heat) and an open water/glycol circuit which acts as heat sink (condenser).

    The rankine circuit is – similar to the A/C circuit – a thermodynamic cycle. The principle works like this:
    In a first step the feed pump provides the working fluid for the expansion device, whereby the steam valve is used for controlling this system. It can either set the exit temperature at the evaporator or a defined mass flow. In a next step the evaporator transfers the energy from the hot exhaust gas to the fluid and changes the medium’s state from liquid to gaseous. This energy is converted in the expansion device (if not bypassed) to mechanical power and cooled down in the condenser (to guarantee a liquid state for the feed pump).

    Usable from release: KULI 10
    Necessary modules: KULI base + KULI ecodrive


    KULI File, 50 KB
    You do not have permission to download this file
  • Resistance Matrix based on a 2D Fan curve
    16.02.2015
  • KULI-System

    Based on the 2 dimensional characteristic, a 3D profile can be created by rotating the symmetric profile around the central axis. Based on this Profile, the pressure distribution of the fan can be added to the cooling package. Due to the uneven flow distribution, the performance of the cooling system will be influenced.

    Usable from release: KULI 9.1-0.01
    Necessary modules: KULI base


    KULI File, 68 KB
    Documentation, 489 KB
    You do not have permission to download this file
  • Automatic Creation of KULI Fan Files (rpm and stage controlled) from Excel
    27.11.2014
  • KULI-System

    These Excel Input sheets can directly be used to create KULI component files for speed and stage controlled fans. Additionally exiting component files can be imported and edited without a regular KULI installation.
    For the use of these templates, KULI CompInterface and KULI MediaX are required!

    Usable from release: KULI 10
    Necessary modules: KULI CompInterface + KULI MediaX


    KULI File, 157 KB
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  • Evaporator test bench (adjustment)
    17.11.2014
  • KULI-System

    KULI’s hvac components like the evaporator are based on a combination of geometrical and test data. To achieve a good accuracy of the model, a successful calibration is obligatory.   This virtual test bench provides a model that supports the user to find the ideal calibration factors.

    The evaporator is a core part of each HVAC system. In KULI, the model of the evaporator is based on a combination of geometrical and test data. In a first step all available geometrical data is defined directly in the component. Next, the simulation model is calibrated based on these input values by the use of various fitting values. These values influence the pressure losses at the refrigerant side and at the air side. Additionally they also effect the heat transfer for the refrigerant side and the air side as well as the condensate mass flow (evaporator) . The calibration can be done automatically in the KULI component, but for getting even more accurate results (with respect on specific simulation points) this Excel-KULI Co simulation test bench can be used.

    Usable from release: KULI 9.1-0.01
    Necessary modules: KULI hvac


    KULI File, 165 KB
    Documentation, 882 KB
    You do not have permission to download this file
  • Steady state investigations of a cooling system including an indirect charge air cooler (CCFC)
    14.11.2014
  • KULI-System

    Due to constructive and performance reasons, indirect charge air coolers are more frequently used in state of the art cooling systems. Therefore this example demonstrates how a CCFC can easily be included in a steady state simulation model, whereby a low temperature radiator is added in the frontend and the coolant cooled cross-counter flow cooler (CCFC) is mounted next to the engine.

    The KULI file shows the simulation model of a passenger car, including the main cooling circuit with the heat input of the engine, a simplified oil circuit and both sides of the indirect charge air circuit.

    The CCFC is based on measurement values and geometrical input, therefore the data input differs from the traditional charge air cooler. At first, the user has to set up the geometrical properties and the configuration of the layers. In a next step, the measurement data defining the heat transfer and the pressure loss must be entered. The data can be input in a single table (no need for additional cold measurements of the pressure loss). To use this data, a calibration is obligatory. For the best result, the user can choose between different calibration methods like linear, quadratic or cubic.

    The calibrated CCFC is included in the charge air circuit (outer side) and in a low temperature coolant circuit, which is located in front of the main radiator.

    Usable from release: KULI 10
    Necessary modules: KULI base


    KULI File, 18 KB
    You do not have permission to download this file
  • Peltier Element (Thermo Electric Cooling)
    12.11.2014
  • KULI-System

    By the flow of electric current, the Peltier Element can be used for cooling/heating – similar to a traditional heat pump. Due the fact that for a good performance a high electrical conductivity but a very low thermal conductivity is required, semiconductors are usually used for such elements. 

    Basically this example demonstrates the use of a Peltier element in a steady state cooling system. The model consists of a cold and of a hot side, whereby electric current is used to cool down an air flow. Both sides of the element are connected by a heat conduction element with a very small lambda value. Keep in mind that due to the use in a steady state model, the point mass is only used for modeling the heat transfer, therefore the simulation ignores the thermal inertia. 

    Basically the amount of heat rejected / absorbed by each side is the sum of the Peltier effect (current [A] * temperature of the cold side [K] * alpha [V/K]) and half the Joule heat (0.5*current [A] * current [A] *resistance [Ohm]). Cause of the current being squared for the Joule heat, at a certain point increasing the current will lead to a reduced cooling effect (for high currents the cooling effect can even turn into a heating effect).

    Usable from release: KULI 9.1-0.01
    Necessary modules: KULI base + KULI drive


    KULI File, 45 KB
    You do not have permission to download this file
  • Advanced Modeling of PCM material (variant no. 2)
    09.10.2014
  • KULI-System

    In this example phase change material (PCM) is connected to a fluid circuit.
    Phase change material can store a high amount of energy due to its very high thermal inertia. This energy can e.g. used for a fast engine warm-up, to provide cooling performance in the HVAC system (evaporator) while no compressor is available, …
     

    For the modeling of the phase change material, a subsystem containing a network of controllers is included. Additionally a virtual point mass (Phase Change Point Mass, only for internal calculation) is created   and directly connected to the point mass in the fluid network. The heat is set at this virtual point mass, which directly sets the temperature at the coolant side PM. 

    The basic idea is that the sensible heat is calculated and only this “effective temperature changing” value is set at the virtual point mass. To take care of the melting / solidification energy, the actual change of enthalpy is calculated by a continuous evaluation. If the enthalpy is below / above the hold point, the subsystem can use the cp values for these areas and calculate the temperature change. 

    For simplification purposes, the cp value for the solid and for the liquid phase is constant, the change of enthalpy due to the phase change is considered in the melting heat.

    Usable from release: KULI 9.1-0.01
    Necessary modules: KULI base + KULI drive


    KULI File, 9 KB
    You do not have permission to download this file
  • Definition of constant pressure drop (air path)
    02.10.2014
  • KULI-System

    Usually the pressure loss in a component placed in the air path depends on the resistance, the mass flow rate and the temperature. Anyhow it could be useful to set a constant pressure loss. This can easily be done by the combination of a calculation controller with a media controller.

    Usable from release: KULI 9.1-0.01
    Necessary modules: KULI base


    KULI File, 27 KB
    You do not have permission to download this file