Dr. Arne Jachens
[GPIO] [SPI] [I2C] [RS232] [PCB] [1wire] [motor] [zwave]

Solar Heating and Ventilation Control based on Raspberry Pi

Raspberry Pi Logo Keywords: RaspberryPI, Home Automation, Temperature Sensor, AD converter, Relay, Solar, Heating, Ventilation, Control with Web Interface,Data Logging

Abstract: To create a solar heating control this article describes how to connect temperature sensor via SPI to a RaspberryPI and how to use GPIO-pins to control relays. In the second part there are detailed control algorithms for a combined solar and combustion heating with web interface to visualize the data logging and as control pannel.

 

Motivation

When my heating control broke down I decided to create my own to

  • implement my own control algorithms
  • have an easy to use web interface
  • be able to repair it myself!
  • safe money

As heating setup I have one central hot water storage tank (550 l Water including 180 l tap water), which provides heat for warm water consumption and heating of my house.
There are two possibilities to heat up this tank which have to be controlled:

  1. Solar heating
    One solar collector (6.93 m2, (TK-Solar) with pump and sensors for hot loading temperature and return flow temperature .
  2. Wood pellet burner
    The Calimax "Twist 80/20" oven has its own control for lighting the fire and control the circulation pump.
    To activate it there are contacts which have to be closed without potentitial by my control. To do this a second relay is needed.
So far I have 4 sensors (Ttank, Tcoll, Tload, Tret) and 2 actuators (Asolar, Aoven) to handle... So let"s set up the RaspberryPI, design the electronis, implement the communication and design the control.