Thermal control in the renovation of a historic building

The Application Context

A few steps from the centre of Turin, adjacent to the park of Valentino overlooks a recently renovated building consisting of 5 apartments. The renovation has made it possible to enhance the historic facades of the building by modernising the thermo-electric plant with new automation and control functions.

Customer Requests

During the renovation it was decided to maintain a single boiler for the centralized management of the heating system and the heating of drinking water. To ensure maximum flexibility and meet the needs of each apartment, it was decided to use the Ekinex EK-LM2-TP logic module.

Ekinex Solutions

The EK-LM2-TP logic module is a KNX device that allows you to flexibly solve small automation needs. This can be done by completing the functions of existing devices, if they are not suitable for a specific need, but also by implementing autonomous logic, perhaps avoiding the need to resort to more complex and expensive devices. In this specific case, all the functions have been managed with a single module, but it is worth noting that several other functional blocks remain unused in the same device, which may in the future be used in other parts of the plant. In this case, the delivery pump of the heating system must be activated if one of the five apartments generate the call signal.

When all requests cease, the pump must remain in operation for another 10 minutes to avoid interruptions and frequent restarts.

The flow temperature of the heated water must always be at least 10°C higher than the setpoint set for the boiler; otherwise, an auxiliary electric heater must be activated until the minimum threshold is reached.

The electric heater may remain on for a maximum of 30 minutes; if at the end of this period the temperature is still too low, the heater must be switched off and a flashing warning light must be on.

It is interesting, by way of comparison, to see how the same application could have been developed using the EK-IA1-TP PLC. This is a device that can be programmed in the same way as industrial PLC, with which it shares the computing power and the vastness of the field of application (certainly higher than the needs of almost any KNX system); in a relatively simple situation such as that of our example, such a high performance device would not be required, but the comparison is equally instructive. The structure of the application has been deliberately kept unchanged for clarity, and for the same reason we preferred the use of "ladder" diagrams: