Kühlmediums

Kühlmediums, in engineering and laboratory contexts, are fluids circulated to remove heat from equipment, processes, or samples. They form the circulating part of heat-exchange circuits and determine the efficiency, temperature range and safety of the cooling system. In industrial process cooling, this can mean coolants in closed-loop systems, while in laboratory settings it may refer to circulating baths or chiller circuits.

Common Kühlmediums include water, often with corrosion inhibitors and anti-fouling additives; water–glycol mixtures (ethylene glycol or propylene glycol) to lower freezing point; mineral oils or synthetic oils used where water is unsuitable; dielectric fluids for electrical equipment such as transformers or high-voltage apparatus; and specialized refrigerant-based fluids in vapor-compression systems. Each medium offers trade-offs in heat capacity, viscosity, freezing/boiling points, chemical compatibility, and environmental and safety profiles. Water provides high heat capacity but risks corrosion and biological growth; glycol mixtures extend operating range but increase viscosity and cost; oils are good lubricants and non-conductive but poorer heat transfer in some cases; dielectric fluids minimize electrical risk but may be expensive or toxic.

Selection depends on operating temperature, system materials, required heat transfer performance, electrical safety, and environmental regulations. Maintenance includes monitoring concentration and pH or inhibitors, filtration to remove particulates, and periodic replacement to prevent microbial growth or phase separation. Environmental considerations favor low-toxicity and recyclable media. In critical applications, specifications from manufacturers and standards govern acceptable media.