# Development of a Wireless System to Control a Trombe Wall for Poultry Brooding
## 3 Results and Discussion  
In Figures 7 and 8, it is possible to observe in the \"payload\" field the information arrival, in bytes, obtained from the temperature sensors located in the air gap and in the internal environment to the TTN platform (server). The corresponding response is also presented, as well as the Device ID and the time of the message. As previously referenced, the data are converted to decimal values throughout a decoder for further graphical plotting  
Figure 6: Implemented ThingHTTP to open the XPS boards. in ThingSpeak application. However, field 1 plays the key role to make a decision, once it gives the temperature differential between both sensors (DHTcam--DHTli). As pointed out, if that temperature range is below 10 \({}^{\circ}\)C, React and ThingHTTP schedule the downlink of one byte \"00\" in TTN, which in the microcontroller interpretation are closing the XPS boards. If the difference is higher than 15 \({}^{\circ}\)C, it schedules the downlink of \"01\", which gives the instruction to open the XPS boards. Additionally, as it is only possible to do a downlink schedule and the microcontroller also uplinks the external shading device state (0 if closed, 1 if opened, and controlled by the microcontroller's Real Time Clock), the server takes advantage of that and makes the downlink (send the data to the microcontroller while the receiving window is open). In this case, in order to save energy, a class A LoRa device is implemented, meaning that it is only possible to schedule downlinks, and therefore, the microcontroller only has a brief receive window after uploading a message to the server. As the proceeding of opening/closing the XPS boards is not urgent relatively to the frequency that data are sent from the end-node to the server, it can be performed in the next uplink, as seen in Figure 7 and 8. In the microcontroller, the recvfrom function returns the data in bytes, followed by the port by which the data were sent from the server. In Figure 9, after parsing the received information, the closing instruction of the XPS boards can be observed, after being analyzed. The graph presented in Figure 10 shows the temperatures values acquired during one week measurement period, when the experimental device was subjected to the climate conditions of a northern Portuguese city. Temperature measurements were made every five minutes. A data set of 1730 values was stored. As mentioned previously, the air vents opened when the temperature differential between the air gap and the interior was higher than 15 \({}^{\circ}\)C and closed when it was lower than 10 \({}^{\circ}\)C.  
Figure 8: Closing the XPS boards (field1 \(<\) 10 \({}^{\circ}\)C). Figure 7: Opening the XPS boards (field1 \(>\) 15 \({}^{\circ}\)C). Figure 9: Reception in the microcontroller. Although the daily opening periods of the XPS boards were reduced, the maximum temperature values compatible with brooding were easily achieved but not exceeded. In general, the higher values of interior temperatures were obtained when compared with the ones obtained outside, showing the influence of the heat storage capacity and heat delay of the Trombe wall system when integrated in the envelope of a poultry brooding building. Although this study constitutes a first approach to the implementation of a passive solar system remotely controlled by a long-range and low-cost wireless technology, it is possible to observe the suitability of these solutions to other types of buildings that are not residential or commercial, as usual, such as poultry brooding where controlled indoor temperatures are required. The obtained results show the crucial role of the air vents management to guarantee the interior comfort with low temperature fluctuations. Thus, sending a decision remotely to open or close the XPS boards contributes to the Trombe wall thermal performance optimization. Opening the XPS boards during winter periods improves the heat transfer through the air vents so higher temperatures values can be easily achieved inside the room.