Boosting Heating/cooling With a Convector

I'm heating my home with a heatpump. To keep the efficiency of the heatpump as high as possible I try to keep the water temperature as low as possible. A downside of low water temperature is that convection is very low, even convectors. To overcome this problem I've added a touch of smart home to the convectors, by adding PC fans to boost the heat exchange. These are dependent on the room and water temperature. In total 4 rooms are boosted like this.

A plus side is that the system also allows me to take full advantage of the heatpump by cooling the rooms during a hot summer evening.

1x 12v power supply

1x Shelly 1 (dry contact and 12v possible)

1x Shelly temperature addon

2x ds18b20 temperature sensor

4x low noise PC fans (120mm) (I'm very pleased with the Artic F12 silent)

Some Wago's

some various connectors (power supply to wire, PC fan connectors)

electrical wire (suitable for 12v)

Insulation tape

small electrical box

Foresee a regular electric socket close to the convector.

Connect the power supply in the correct way to the smart relay.

Make sure your fans are correctly connected as well (+ from the power source and - from the output of the relay)

In addition put the temperature extension on the relay and solder the sensor to the extension.

place everything nicely into an electrical box for safety.

here is a link containing the details on how to correctly connect.

Shelly 1 - Shelly Cloud

Place everything in the right place:

Pc fans in the correct way (airflow up). Best to also put them on small rubber feet to avoid vibration noise

electric box against the wall

One temperature sensor in the convector element and another outside of the heating enclosure to have the correct temperature measures at all time, this is not yet done on the picture, because I'm still looking for a nice "camouflaged" box.

Now you still have to program the relay. This can be easily done by the GUI interface of the relay, off course other ways are possible as well, but if you know this possible I shouldn't say more...

Sensor 1 = room temperature

Sensor 2 = water temperature

H&T: temperature sensor in a non conditioned room --> reference

The first picture describes the conditions for activation.

Heating: If water temperature is higher than 25°C and the room temperature is lower then 17°C turn on.

Cooling: If room temperature is higher than 26°C and the water temperature is lower then 21°C turn on.

An active time is set as well to avoid activations during the night

The second picture describes the conditions for shutting down.

The logic is the same, however for each step a reference is taken with (H&T) as this indicates the climate condition --> high temperature (summer), low temperature (winter). This is only necessary by combining cooling and heating.

Further more a daily shutdown is planned at 22h30 to avoid noise during the night

Now you can create a lot of evolutions:

in fact only one room has 2 sensors, the other rooms only have one (combined with humidity). For water temperature they refer back to the second sensor in the room where the heat is always on.

Another one I'm thinking of, is how to let the heatpump react to different room temperatures, now the heatpump is controlled by a one control unit which needs to be physically placed in a room. Given that all these sensors are present, it would make sense to start using them.