In our diploma we tested a panel system filled with PCM for the purpose of cooling the air in the room. The system is a smart solution to reduce the energy consumption we use for cooling. In the first part of our diploma we made an overview of latent storage tanks and PCM in general. While doing the experimental measurments we measured the temperature in the air duct of the system, temperature of the plates and the time needed for PCM to fully melt and solidify. In the analysis we compared the measured temperatures, time needed for the processes to be completed and how much energy was used or was accumulated for an individual measurment. We found out that the fastest way for PCM to solidify, it is necessary to supply air for more than 3 hours to the air duct at the speed rate between 0,7 m/s and 1,7 m/s, and that it's better if the temperature difference between the air in the air duct and the air that is being blown in to the duct is as high as possible.