Testing on test benches take up a lot of resources, are tedious and expensive. We enable tests with virtual prototypes of heat pumps, refrigerators or energy technology plants. This increases your test coverage, improves the quality of your control software and avoids errors in the field.
We will be happy to discuss your use case.
Modelling thermal systems such as refrigeration cycles in heat pumps is complex. This is why control systems are often tested as they were 40 years ago: in elaborate experiments on test benches in the laboratory.
In contrast, hardware-in-the-loop (HiL) tests have long been established in the development of controllers for mechanical and electronic systems. Here, the controlled system is mapped virtually as a simulation model. In this way, the control unit can be tested in a closed control loop, even without a real prototype of the plant.
Test benches always fully booked
Is everything really tested?
Long iteration loops
Software problems only discovered by the customer
Risk of callbacks due to increasingly complex functions
Another compressor destroyed...
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Faults often occur under extreme conditions. On the test bench in the laboratory, extreme conditions are associated with a great deal of effort.
In hardware-in-the-loop tests, extreme conditions can be simulated very easily. No matter whether 20 °C or -60 °C. That way you can find errors already during tests and not only in the field.
Via HiL, you can test the current software status in a closed control loop at any time. Also automated over night.
Image source: speedgoat.com
Measurements on the test bench always contain uncertainties. Tests with simulation models are 100 % reproducible. This means that errors can be avoided in future software updates through regression tests.
HiL tests with a virtual prototype enable early and systematic testing. This allows you to detect problems and errors early in the development process. Not just on the test bench in the laboratory or in the field at the customer.
With the simulation models as virtual prototypes, control algorithms can be tested from the first idea to the final version, allowing software and engineering teams to work in parallel. This saves time and enables shorter development cycles.
To support technical sales at NEUMAN & ESSER, we have developed a customized web-based application for the dynamic simulation of hydrogen refueling stations.
Customer requirements such as type and number of refueled vehicles can be selected. The filling station can be configured in detail and in a simulation the dynamic behavior of the overall system is calculated for a typical period of time.
With this tool, sales staff can configure the product "filling station" according to customer requirements without time-consuming detours via engineers. Interested parties receive direct and detailed feedback.
Hydrogen Refueling Station Simulation and Design Tool by NEUMAN & ESSER, Youtube video
Emerson develops components and systems for supermarket refrigeration. Due to its environmental benefits CO2 as refrigerant is becoming more and more important in this sector. But compared to traditional refrigerants the thermodynamic properties of CO2 are totally different (high pressures and low critical temperature). Designing efficient CO2 cycles is challenging and there are many different cycle concepts proposed. Together with Emerson experts we have developed simulation models for a number of different concepts and run a simulation study to compare the seasonal efficiency of these cycles.
Eric Winandy et al.: Assessment of the seasonal efficiency of different CO2 booster architectures for different climates. DKV Jahrestagung, 2018
In their development process of heat pump controllers Vaillant has established a comprehensive testing strategy. Before they connect developed controllers to real heat pumps in their lab, they are connected to virtual heat pumps running on special real time simulation hardware and software from dSPACE. Crucial ingredients for this so-called Hardware-in-the-Loop (HiL) tests are simulation models of the heat pumps, that are accurate, fast and robust. We developed these models for Vaillant using our Modelica library TIL Suite and set up a reliable tool chain to export these models to dSPACE platform. The models include a full dynamic physical model of the refrigeration cycle. It can handle switching of refrigerant flow direction caused by different modes for defrost, heating and cooling. Vaillant is now able to detect issues in control code much earlier and saves with this virtual testing a considerable amount of expensive lab experiments.
Manuel Gräber et al.: Physical Modeling of Heat Pumps for Hardware-in-the-Loop Testing. 13th International Modelica Conference, 2019
Together with Volkswagen we have developed simulation models for battery thermal management systems. Geometry of cooling plates and its flow patterns are taken into account by discretization with finite volumes. Compared to detailed CFD simulations the spatial resolution is much lower but still high enough to achieve confident results. This approach reduces the computation time dramatically enabling usage of numerical optimization algorithms or large-scale simulation studies. Cooling systems can be designed with less pressure loss and increased energy efficiency.
Robert Wendland et al.: Dynamic Optimization of Thermal Management and Cooling Plate Design for Battery Systems. 27th Aachen Colloquium Automobile and Engine Technology, 2018
We have co-developed the TIL Suite together with our partner company TLK Thermo over the last 15 years and established it worldwide. With the latest methods, we can also robustly calculate zero mass flow and flow reversal.
In HiL tests, Euler solvers with a fixed step size are standard. For thermodynamic systems, this quickly reaches its limits. We use numerical differential equation solvers with variable step size. This way we can achieve 100 % robustness.
Thanks to the FMI interface, our models are compatible with HiL software from various suppliers such as dSPACE or Mathworks/Speedgoat. You can easily integrate our models into your existing in-house solutions.