### CHPC: Cheap Heat Pump Controller v1.0
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.
## Development
State: active
## Applications:
| Usage. | Brief description. | Application examples | Available protections |
| ---------- | ------------------ | ------------------ | -------------------- |
| 1. Thermostat. | Precision thermostat. Simple and cheap.
Only 1 relay and 1 temperature sensor required.
| 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)
## 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).
\* 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)
## 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.
Prototype 1.
History ) But worked well for a season.
## BOM (Bill Of Materials), PCB v1.1:
| 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
| IC | ds18b20 | 6 | | 1 to 13, 6 recommended as fast start |
| Conv | usb→uart | 1 | | To upload firmware |
| - | current sensor sct-013-000 1
| Conv | rs485-USB | 1 | | To connect CHPC < - > PC/notebook |