Cheap Heat Pump Controller

thingiverse

# Cheap Heat Pump Controller (CHPC) The CHPC is a minimal cost heat pump controller that can be used as provided or adopted to nearly all use cases due to its open source nature. ### Applications: 1. Thermostat _Brief_: A precision thermostat that is simple and cheap, requiring only 1 relay and 1 temperature sensor. _Application examples:_ Room heat control, chicken coop climate control, distillation column, else. 2. Heat Pump (HP) Controller _Brief_: A heat pump controller that drives HP system components: compressor, cold and hot side circulating pumps (CP). It protects the system from overload, overheat, and freezing up, and drives EEV to optimize HP running conditions. _Application examples:_ DIY heat pump system, repair module for commercial systems. Water heater, house heating systems, and more. _Available protections_: Compressor: cold start or overheat. Discharge and suction lines protection. Short-term power loss. Anti-freeze. Power overload protection. Others. 3. EEV Controller _Brief_: An EEV driver with no relays, requiring 2 temperature sensors. _Application examples:_ Upgrade your system from capillary tube to EEV. _Available protections_: Protects from liquid at suction line by design. For more information about heat pumps, see [Wikipedia about HP](https://en.wikipedia.org/wiki/Heat_pump). ### Features: * Up to 13 temperature sensors (more info: github page) * 5 relays (compressor, hot CP or air fan, cold CP or air fan, sump heater, 4-way valve) * 4 inputs * 5/6 pin EEV connection * 1602 display support * RS485 or Serial (UART 5V) support * Automatically turns on/off system when heating is required * Takes care of system components health ### Control Interfaces: None: Target temperature uploaded to board with firmware and cannot be changed. System used as fixed thermostat. Target temperature can be changed later with firmware re-upload. 0.96 OLED or 1602 LCD screen + buttons: Simple, local screen controlled system. Remote control is not possible. Remote computer terminal over RS-485 line: Target temperature and running conditions under remote control. User can get stats from all T sensors. Up to 1.2 kilometer line. Remote automated control/stats via RS-485: Firmware was written with python scripting in mind (and real scripts at prototype 485 network). Both screen+buttons and RS-485: Combination allowed. * RS-485 specification. Hardware test succeeded on 400 meters line. ### Relays: "Thermostat": Only 1 Relay: drives electric heater (any) Heat Pump: Capillary tube, TXV, EEV: 5 Relays, drives all you need: * Compressor (can be used as external relay driver for High Power systems) * Cold Circulating Pump (CP) * Hot CP * Sump Heater (optional, recommended for outdoor HP installations) * 4-way Valve (support coming up: autumn 2019) ### Temperature Sensors: Up to 13 temperature sensors can be connected to CHPC to control all processes that you want. Only 1 sensor needed for "Thermostat" or "Heat Pump capillary/TXV" 3 sensors needed for "HP with EEV" (absolute minimum scheme) See [https://github.com/gonzho000/chpc](https://github.com/gonzho000/chpc) for more details and firmware