Its nice to have a high-quality control device, but its even nicer to use it to control your house. In this log I want to showcase how we use the ControlBox in our own house.

During the renovation of our house, we had to supply a calculation of the heat dissipation in our house to apply for the permits. I found a very useful example of such a calculation, made by Steven van Lier. The original calculation can still be found here. We converted this calculation to represent our own case, and we added some calculations to estimate what kind of heat sources we would need in different use cases to heat our house. It gave us a nice overview of what is required, and why. Our own variant of this calculation is available here.

Finally I created a schematic to supply an overview of how the different heat-supplying and heat-buffering devices in our house are inter-connected. The schematic is available here.

I think we did some less-conventional things to reduce energy consumption.

• We use a small heat-pump water boiler (input power 400 Watt) to supply heated tap water.
• We have a heat exchange between the tap water boiler and the two hot-water buffer boilers in the attic.
• We can provide heat from the heat-pump to those buffer boilers, but we can also bring back heat from the buffer boilers to the tap water.
• As we also have a vacuum-tube heat collector on the roof of the house, we are able to switch the (electricity consuming) heat pump off in summer time; in this period hot water is provided by the heat collector.
• In winter time, the heat transfer will be directed in the other direction; the heat pump and the heat collector will both heat the hot water buffers.
• Using those hot-water buffers we are able to lower the temperature at night, while we still have comfortable temperatures when the day starts.
• Because the heat pump we use is a air-to-water heat pump, we also use it to ventilate our house.  By supplying the heat pump with the relative warm ventilation airflow, the efficiency of the heat pump increases.

In order to regulate & coordinate all those tasks, the ControlBox is used. The ControlBox will:

• Read all temperature sensors t_x.
• Switch valve A, B and C. Use 24VAC for safety reasons
• Switch the motors on floor heater distribution group
• Control the flow of pump p₁ and p₄ via PWM signal.
• Switch all pumps on/off
• Check via internet outdoor temperature & weather forecast

With the input of the temperature sensors the ControlBox can:

• Verify if there is a request for heat on 1st floor (living room/kitchen) is (t₁₄).
• Verify if there is a request for heat on the 2nd floor (t₁₃).
• Calculate the amount of heat dissipation of the house (t₈ en t₉)
• Check if wood stove is burning:
  t₁₅ will go high: switch off floor heating. If delta between t₁₅ and t₁₆ gets too large switch p₁ on.
• Balance and regulate the heat in the heat-buffer boiler, tap water boiler and solar collector (t₁ to t₇ , t₁₀ to t₁₂ and t₁₈).

With pump p₃ and valve a, b and c heat can be exchanged from the heat buffers to the tap water boiler or vice versa. Direction of the heat flow can be regulated with valve a and c. In winter time, the heat buffers can be heated by the heat collector, the heat pump and the wood stove. In summer time, the heat collectors can heat also the tap water, and the heat pump can be left off.

Pump p₄ brings heat from the heatcollector to the buffer boiler. The PWM pump is regulated with a PID controller
that regulates the delta between t₁ and t₁₈.  The switch-on moment is defined by monitoring the cumulative amount
of energy that has been harvested by electrical solar panels since the last time it was switched off.

Pump p₂ en p₅ are switched off when not in use .

Heat transfer from wood stove to heat buffer boilers will basically happen via natural circulation (thermosyphon).
This will ensure a safe flow independent from pumps, hardware or software (ensuring safety).
If temperature of t₁₅ gets too high, pump p₁ can be switched on to cool down the heat stove.