The article discusses the question of reasonable application of UV LEDs for disinfection of the fluid mediums. There are the main advantages and failures of modern UV LEDs as well as the perspectives for their development and application presented. The low energy efficiency is noted among the main failures that significantly limit the possibility to use the semiconductor devices. In order to evaluate the efficiency of energy, the thermal model of the radiation system based on UV LEDs has been created. This system provides the energy flow of radiation similar to the flow of the gas discharge lamp of DB75 type. The simulation of this system operation is performed with the passive and active cooling applied to UV emitting diodes. The active cooling system is implemented by the thermoelectric modules used. There is calculation of the thermal processes at various parameters of the active cooling system carried out. Optimal parameters of the cooling system have been determined, at which the most favourable thermal mode of operation of UV LEDs is provided. Due to the active cooling applied it was possible to reduce the weight and size indicators of the system by 12 %. And at the same time its energy consumption increased significantly, that allowed additionally to decrease the energy efficiency. Basing on the developed models of the irradiation system with passive and active cooling there was the calculation of its daily energy consumption performed in accordance with a generic schedule of the water consumption per hour for the household and drinking needs of citizens. The results of calculation showed that if to use even the passive cooling, the system consumes the several times more electricity per day compared to the DB75 gas discharge lamp. It confirms that there are currently significant restrictions on the use of UV LEDs for disinfection of liquid media due to their low energy efficiency. But it should be noted that the technology of UV LEDs production is progressing dynamically. This fact allows us to say with optimism about the possibility to apply the semiconductor devices in systems of disinfection in the future.
