## 3 Results and Discussion  
Measurements of heating of PCMs have already come under examination many times. Our measurements and results of heating the proposed technology are shown in our previous articles [38; 39; 40]. Therefore, the crucial objective of this article was to determine the behaviour of PCM in temperature range specific for cooling. For this purpose, specific heat capacity is parameter of great importance. The value for PCM used is around 6.8 kJ\(\cdot\)kg\({}^{-1}\) K\({}^{-1}\) for temperatures ranging from 10 \({}^{\circ}\)C to 21 \({}^{\circ}\)C. The cooling power is about 400 W at temperature difference 12 \({}^{\circ}\)C.  
The risk of condensation of water vapour is the most important factor limiting the use of cooling devices. To prevent this from happening, ensuring that the temperature of their surface is at least 1 K above the dew point of the ambient air is crucial. For this purpose, the technology is able to monitor the value of the ambient temperature, humidity and dew point temperature. Technology is set to keep the temperature of the thermal panels as low as possible but still above the dew point. Simultaneously, technology is able to compared energy gained from the PV and consumed by TEC modules (or HP)--in case of low energy gains are turning off some TEC. Of course, this automatic control mode can be by-passed and the technology can be operated manually without all restriction.  
Figure 4: TEC assembly type L.L.-210-24-00-00.  
The heating and cooling performance of the accumulation device is also important. For this purpose, it is important to know the specific power, which is given by the value of the heat transfer coefficient and the active area. The average heat transfer coefficient is about 6.4 Wm\({}^{-2}\)K\({}^{-1}\) and the active area is 5.2 m\({}^{2}\). So, the specific heating/cooling power is around 33.2 WK\({}^{-1}\). It is, therefore, clear that the cooling power is dependent on the temperature difference between the surface of the panel and the ambient temperature. The higher temperature difference means higher the power. As previously mentioned, the used PCM has a temperature range of phase change between 18 \({}^{\circ}\)C and 22 \({}^{\circ}\)C. When active cooling is on, the sensible heat is removing as first (above 22 \({}^{\circ}\)C), then the phase change occurs (between 22 \({}^{\circ}\)C and 18 \({}^{\circ}\)C) and then the sensible heat is removing again (under 18 \({}^{\circ}\)C). The surface of the panels can be cooled to the dew point, but the most amount of energy is able to accumulate during the phase change. If the panel temperature is around 18 \({}^{\circ}\)C and the ambient air temperature is 25 \({}^{\circ}\)C, the cooling power is approximately 230 W. For example, at a temperature difference of 15 \({}^{\circ}\)C, the cooling power is about 500 W.  
As previously mentioned, the proposed technology is designed to be able to use the power produced by the PV. Energy production covers the consumption of TEC modules with an average cooling output of about 550 W. This power is higher than the average cooling power of the accumulation panel. However, TEC modules lower the latent heat of the PCM panel, i.e., the surface temperature does not change much, but accumulation panel is able to accumulate much more energy for later utilisation. If the phase change limit value is reached, the surface temperature of the panel starts to decrease rapidly. The lower temperature increases cooling output, but when the technology is turned off, the temperature returns quite fast back to the phase change range.  
During designing and initial measurements was discovered a technical problem with overheating in cooling mode. This is described in the following subsection. After this, there are presented results of measurements with solved the problem out.