### 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> <br><br> ## Development State: active <br><br> ## Applications: | Usage. | Brief description. | Application examples | Available protections | | ---------- | ------------------ | ------------------ | -------------------- | | 1. Thermostat. | Precision thermostat. Simple and cheap.<br> Only 1 relay and 1 temperature sensor required.<br> | Room heat control. Chicken coop climate control. Distillation column or Yogurt maker t. control. 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. | \* under development For more information about Heap Pumps look at [Wikipedia about HP](https://en.wikipedia.org/wiki/Heat_pump) <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> \* RS-485 specification. Hardware test succeeded on 400 meters line. <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)  ## Get your own CHPC: * download PCB gerber files * 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 * solder * install firmware * install CHPC at your system * enjoy ## T sensors abbreviations: This abbrevations used in interface during installation procedure | 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 | ## Photos: This is prototype 2. 1602 is the best choise.   ## BOM (Bill Of Materials): | Type | Name | Quantity | Case | Comment | | ---- | ---- | ----- | ---- | ---- | | R | 10k ¼W | 2 | R | 1k ¼W | 16 | R 100 ¼W 1 | R 22R ¼W 1 | R 10R ¼W 1 | Cap 0.1 uf 4 | Cap 22uf_16v 4 | IC PC817C 2 or 4 DIP-4 2 if you use buttons instead of inputs | Conn DIP-16 bed 3 DIP-16 | IC ULN2003APG 2 DIP-16 | IC 7805 TO-220 1 TO-220 | IC 2n2222 1 TO-92 | - SMIH-12VDC-SL-C 2 | - SRD-12VDC-SL-C 3 | Module TTL_485_MODULE_8PIN 1 | Module ARDUINO PRO MINI 328P 5V 1 | Conn KF128 2.54_screw_1x2 1 | Conn KF128 2.54_screw_1x4 1 | Conn KF128 2.54_screw_1x6 1 | Conn KF128 2.54_screw_1x12 1 | Conn KF128 3.81_screw_3P 5 | Conn KF128 5.08_screw_2P 3 | Conn 2.54_legs_female_x2 1 like used at arduino mega | Conn 2.54_legs_female_x3 1 | Conn 2.54_legs_female_x4 2 | Conn 2.54_legs_female_x12 2 | Conn 2.54_pins 20 | Button momentary switch 6x6 2 2 | Display 1602 LCD with i2c interface 1 | - buzzer 1 R9.0-2P-4.0PITCH | Module LM2596S module 0 or 1 XX-to-12 stab Needed only if you will use 24v as power source | - power source, 12v1.25A 70x30x40 1 70x30x40 | - ds18b20 6 1 to 13, 6 recommended as fast start | usb→uart 1 To upload firmware | - current sensor sct-013-000 1 | rs485-USB 1 To connect CHPC < - > PC/notebook