Temperature control is a critical factor in stress and load testing during the development of alternative drive solutions, batteries, materials and other vehicle components.
This type of testing often dictates that the heat transfer fluid (HTF) used is a water-ethylene glycol mixture. For these applications, Huber has expanded its portfolio to include temperature control systems designed and tested specifically for use with water-ethylene glycol over the temperature range of -45°C to 95°C for the auto industry.
It is based on the proven Unistat technology, developed by Huber over 40 years ago. The solution operates with a very low volume of HTF, uses plate heat exchangers for efficient thermal transfer and has a sealed fluid system. This results in very short ‘time to temperature’ times, and extremely responsive, stable, accurate and repeatable temperature control.
The Unimotive series comprises five units with up to 35kW cooling capacity and 24kW heating capacity. The models are fitted with a magnetically coupled, speed-controlled pump with a maximum flow of 145l/min and pressure up to 5.5 bar.
New innovation: Unimotive XT with water-glycol up to +150 °C
The new Unimotive XT models are designed for working temperatures up to +150°C, operating with water-glycol. The high-temperature models set new standards, with a unique, fully integrated and variable system pressure concept.
The overpressure in the liquid circuit can be set to a fixed value or as a ramp for the ranges above the boiling point. Variable system pressure provides better protection for the application at low temperatures. Another advantage is that no external pressure is necessary for operation, i.e. Unimotive does not require any special infrastructure (for example nitrogen gas tanks or similar). Also, the Unimotive expansion tank remains pressureless, which simplifies the risk assessment.
Volume flow control for validated measurement results
The Flow Control Cube (FCC) was developed for flow rate measurement and control. This optional addition to the Unimotive devices is available in two options: either as a space-saving version mounted on top of the temperature control system or fitted with castors and placed directly on the floor. In both variants, the bypass, flow meter, interfaces etc. are housed in a compact stainless-steel module.
Flow measurement is carried out with magnetic-inductive flow meters or via a turbine flow sensor and operates over the range of 0.2l/min to 95l/min depending on the model.
Unimotive devices can be individually configured and adapted to various test situations or integrated into existing test benches. Various sensors, expansion vessels, pumps and data interfaces are available as accessories to adapt to an application.
Custom designed solutions for demanding applications where for example high pressures are required, or aggressive fluids are being used, can be designed and built. They incorporate a system separation design method splitting the primary and secondary circuit and thermally coupling them through an external heat exchanger.
All Unimotive models are operated using a touchscreen controller that supports the most common data communication protocols (including Profibus, Modbus, TCP, Ethernet, OPC-UA, RS232, USB), enabling easy integration into automated industrial environments.
The Unimotive devices can also be used as an alternative to, or to supplement/widen the temperature range of environmental chambers. One advantage here is the increased responsiveness of the temperature control, meaning the target temperature can be quickly and precisely achieved under varying thermal conditions in the test specimen. A combination of the Huber temperature control system plus an environmental chamber also enables simultaneous control of the test specimen temperature as a function of the ambient temperature.
In addition to the Unimotive systems, Huber offers a wide range of other temperature control solutions for applications from -125°C to +425°C. The Unistat product family includes more than 70 basic models with cooling capacities up to 130kW. In addition to closed circulation thermostats, the product range consists of chillers and heating/cooling circulators with open baths as well as calibration baths, heat exchangers and customized special devices.