## 4 Methodology
### Analysis of an Upgraded Method of Operation of Various Building-Energy Systems
#### 4.3.1 Control of Thermal Barrier Operation in Active Thermal Protection Mode  
The principle of temperature control at the thermal barrier level in active thermal-protection mode is shown in Figure 10. The temperature of the heating or cooling water (sensor \"1\"), is regulated centrally in the source area, together with all circuits of the thermal barrier. The control actuator is a three-way mixing valve with actuator \"3\". The controller \"4\" calculates the actual temperature of the supply heat-transfer medium depending on the setpoint of the thermal barrier temperature (sensor \"2\") in the reference room, depending on whether it is in heating or cooling mode. For larger buildings, we recommend dividing the rooms with thermal barriers into zones according to the orientation to the cardinal directions N-S or NE-SW, where the temperature requirements of these zones for the supply temperature of the heat transfer medium may differ significantly due to the presence of heat gains from the sun. The flow of the heat carrier into the thermal barrier circuits is controlled by the controller based on the comparison of the desired value of the heating or cooling water temperature and the temperature at the outlet of the individual heat and cold storage tanks (sensors \"5\", \"6\", \"7\", \"8\") by controlling the actuators of the respective three-way switching valves, which are schematically shown as item \"9\" in Figure 10, and in more detail in the schematic in Figure 9.  
In the cooling operation, it is important to prevent airborne water vapor condensation on the wall structure's surface. Therefore, each thermal barrier circuit is equipped with a contact humidity sensor (sensor \"10\") installed at the coldest point of the system and a two-way actuated control valve \"11\". If the humidity in the room concerned reaches a threshold value, the controller closes the cooling water supply to the circuit concerned by operating the two-way control valve with an actuator, so-called passive protection. Figure 11 is a block diagram of the thermal barrier level temperature control system solution. The thermal barrier is built as a two-pipe system with switching between winter and summer operations. For each operation, the desired temperature value is set separately. The solar absorber, the long-term heat storage, and the short-term heat storage all supply heating water to the circuits during the heating process. The thermal barrier temperature \(\theta_{TB}\) is controlled to the desired value \(\theta_{sph}\) by changing the heating water supply temperature \(\theta_{s}\) by controlling the actuator of the three-way mixing valve. The outlet temperature of the solar absorber \(\theta_{SA}\), the outlet temperature of the long-term heat storage \(\theta_{L\text{-}THS}\), and the outlet temperature of the short-term heat storage \(\theta_{S\text{-}THS}\) are also sensed. If \(\theta_{TB}=\theta_{sph}\), no control intervention is needed. If this condition is not met, the procedure is as follows:  
1. If \(\theta_{TB}<\theta_{sph}\), the inlet temperature to the thermal barrier circuit \(\theta_{s}\) must be increased and at the same time the heating water supplied upstream of the three-way valve must have a higher temperature than the calculated inlet temperature \(\theta_{s}\). The controller compares the outlet temperatures \(\theta_{SA}\), \(\theta_{L\text{-}THS}\), and \(\theta_{S\text{-}THS}\) in a fixed order and redirects the heating water flow from the device that satisfies the condition. If \(\theta_{S\text{-}THS}<\theta_{s}\), it will commission the peak heat source. It then controls the actuation of the three-way mixing valve--opening the direct path;
2. If \(\theta_{TB}>\theta_{sph}\), the inlet temperature to the thermal barrier circuit \(\theta_{s}\) must be reduced. The controller controls the three-way mixing valve's actuator-closes the valve's direct path. Figure 10: The fundamentals of temperature regulation at the thermal barrier level while using active thermal protection.