### CHPC: Cheap Heat Pump Controller v1.0 <b>The CHPC a minimal cost Heat Pump (HP) controller, which can be used as provided, or can be adopted to nearly all use cases due to open source nature.</b> ## Development State: active ## Applications: | Usage. | Brief description. | Application examples | Available protections | | ---------- | ------------------ | ------------------ | -------------------- | | 1. Thermostat. | Precision thermostat. <br> Simple and cheap.<br> Only 1 relay and 1 temperature sensor required.<br> | Room heat control.<br> Chicken coop climate control.<br> Distillation column or<br> Yogurt maker t. control.<br> | N/A | 2. Heat pump (HP) control. Controller drives HP system components: compressor, Cold and Hot side Circulating Pumps (CP). Protects system from overload, overheat and freezing up. Drives EEV* to optimize running conditions. DIY heat pump system. Repair module for commercial system. Water heater, house heating systems and same. Compressor: cold start or overheat. Discharge and suction lines protection. Short-term power loss. Anti-freeze. Power overload protection. ## <b>Applications:</b> ### <b>1. Thermostat.</b> _Brief_: <b>Precision thermostat.</b> Simple and cheap. Only 1 relay and 1 temperature sensor required. _Application examples:_ Room heat control. Chicken coop climate control. Distillation column or Yogurt maker temperature control. ### <b>2. Heat pump (HP) controller.</b> _Brief_: <b> Heat pump controler.</b> Controller drives HP system components: compressor, Cold and Hot side Circulating Pumps (CP). Protects system from overload, overheat and freezing up. Drives EEV\* to optimize HP running conditions. _Application examples:_ DIY heat pump system. Repair module for commercial system. Water heater, house heating systems and same. _Available protections_: Compressor: cold start or overheat. Discharge and suction lines protection. Short-term power loss. Anti-freeze. Power overload protection. Others. \* under development For more information about Heap Pumps look at [Wikipedia about HP](https://en.wikipedia.org/wiki/Heat_pump) <br> ### <b>Control interfaces:</b> <b>None:</b> 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. <b>0.96 OLED or 1602 LCD screen + buttons:</b> Simple, local screen controlled system. Remote control is not possible. <b>Remote computer terminal over RS-485 line. </b> Target temperature and running conditions under remote control. User can get stats from all T sensors. Up to 1.2 kilometer line.\* <b> Remote automated control/stats via RS-485.</b> Firmware was written with python scripting in mind (and real scripts at prototype 485 network). \* RS-485 specification. Hardware test succeeded on 400 meters line. <br> ### <b>Relays:</b> ### <b>"Thermostat"</b>: Only 1 Relay: drives electric heater (any) ### <b>Heat Pump.</b> 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) ### <b>Temperature sensors:</b> * 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) <br> ## PCB Design There are 2 PCB designs: type "F" and type "G". ## Type "F" features: - **mostly SMD** componens, - **internal power** source, - **10** output channels, - 4 input channels, - 5 relays: 1 * 16A + 4 * 7A, - buzzer, - EEV support, - 16 bit **i2c ADC: on board**, - i2c devices: allowed, - T sensors: ds18b20 on one lane. ## Type "G" features: - **no SMD** components, - **external or board-placed** power source, - **5** output channels, - 4 input channels, - 5 relays: 2 * 16A + 3 * 7A, - buzzer, - EEV support, - 16 bit **i2c ADC: off board**, - i2c devices: allowed, - T sensors: ds18b20 on one lane. # Type "F" PCB  # Type "G" PCB  .... .... Drafts below. Sensors abbreviations: | Abbr. | Full name | | ----- | -------------------- | | Tae | after evaporator | | Tbe | before evaporator | | Ttarget | target | | Tsump | sump | | Tci | cold in | | Tco | cold out | | Thi | hot in | | Tho | hot out | | Tbc | before condenser | | Tac | after condenser | | Touter | outer (outdoor) | | Ts1 | additional sensor1 | | Ts2 | additional sensor2 |