### CHPC: Cheap Heat Pump Controller v1.x <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> <br><br> ## Real life installation. Works from ground heat collectors (loops) to radiant in-floor heating system.  Driving: - EEV, - Heat Pump Compressor (1kW electrical power), - Circulating Pumps, - Sump Heater. Temperature sensors installed: - Before/After Evaporator, - Cold In/Cold Out, - Hot In(used as Target)/Hot Out, - Outdoor temperature, - Sump. Controled via both RS-485 and 16x2 display with buttons. ## Changelog - 13 apr, 2019: EEV support development started - 16 apr, 2019: Standalone EEV (no thermostat) with only 2 T sensors written and debugged - 30 apr, 2019: HP system updated to CHPC - 01 may, 2019: CHPC fully tested and released - 02 may, 2019: PCB rev.1.3 coming up, main feature: lot of DS18B20 inputs - 17 may, 2019: <b>PCB 1.3 tested, [assembly instructions added](https://github.com/gonzho000/chpc/wiki/assembly)</b> - 20 may, 2019: external display support development started <br><br> ## Applications: | Usage. | Brief description. | Application examples | Available protections | | ---------- | ------------------ | ------------------ | -------------------- | | 1. Thermostat. | Precision thermostat. Simple and cheap. Only 1 relay and 1 temperature sensor required.<br> | Room heat control. Chicken coop climate control. Distillation column. Else. | 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. | | 3. EEV controller. | Only drives EEV, no relays. Requires 2 T sensors. | Upgrade your system from capilary tube to EEV. | Protects from liquid at suction line by design. | For more information about Heap Pumps look at [Wikipedia about HP](https://en.wikipedia.org/wiki/Heat_pump) <br><br> ## Features: - Up to 13 T sensors (see "T sensors abbreviations" for full list) - 5 relays (Compressor, Hot CP or Air Fun, Cold CP or Air Fun, Sump Heater, 4-way valve) - 4 inputs - 5/6 pin EEV connection, - 1602 display support - RS485 or Serial(UART 5V) support - Automatically turns on/of system when heating required - Takes care of system components health <br><br> ## Control interfaces: <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.<br> <b>0.96 OLED or 1602 LCD screen + buttons:</b> Simple, local screen controlled system. Remote control is not possible.<br> <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.\*<br> <b> Remote automated control/stats via RS-485.</b> Firmware was written with python scripting in mind (and real scripts at prototype 485 network).<br> <b> Both screen + buttons and RS-485.</b> Combination allowed. \* RS-485 specification. Hardware test succeeded on 400 meters line. Example: day/night setpoint control and data visualisation with "pythonic rs485" way.  <br><br> ## 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) <br><br> ## 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) <br><br> ## Temperature sensors installation example (medium scheme)  <br><br> ## Get your own CHPC: * download PCB gerber file, *CHPC_v1.x_PCB_Gerber.zip* * search google [where to order PCB](https://www.google.com/search?q=order+pcb) or make your own at CNC machine * order electronic components, see BOM (Bill Of Materials) list, *CHPC_v1.x_PCB_BOM.html* * solder, [assembly instructions here](https://github.com/gonzho000/chpc/wiki/assembly) * install firmware *CHPC_firmware.ino* * install CHPC at your system * enjoy <br><br> ## T sensors abbreviations: This abbrevations used in interface during sensors installation procedure | Abbr. | Full name | Required for | | ----- | -------------------- | -------------------- | | Tae | after evaporator | EEV <br>Anti-liquid protection at suction line | | Tbe | before evaporator | EEV | | Ttarget | target | Thermostat<br>Thermostat+EEV | | Tsump | sump | Automatic Sump Heater<br>Sump overheat protection | | Tci | cold in | Antifreeze protection | | Tco | cold out | Antifreeze protection | | Thi | hot in | Hot CP automatic control | | Tho | hot out | Overheat protection | | Tbc | before condenser | Discharge overheat protection | | Tac | after condenser | | | Touter | outer (outdoor) | | | Ts1 | additional sensor1 | | | Ts2 | additional sensor2 | | <br><br> ## Photos:<br>    ## Older revisions and prototypes:<br> PCB v1.1   This is prototype 2 (PCB v1.0). 1602 is the best choise.  EEV development started here.   Prototype 1. History ) But worked well for a season.  <br><br> ## Author: gonzho АТ web.de (c) 2018-2019 If you have any comments or questions, please do not hesitate to contact me.