Project tutorial
Cheap Heat Pump Controller - CHPC

Cheap Heat Pump Controller - CHPC © GPL3+

The CHPC is a minimal cost heat pump (HP) controller.

  • 5,977 views
  • 0 comments
  • 9 respects

Components and supplies

11113 01
SparkFun Arduino Pro Mini 328 - 5V/16MHz
×1
Mfr 25frf52 10k sml
Resistor 10k ohm
×2
Mfr 25frf52 1k sml
Resistor 1k ohm
×20
Mfr 25frf52 100r sml
Resistor 100 ohm
×1
4415447
Through Hole Resistor, 10 ohm
×1
4415447
Through Hole Resistor, 22 ohm
×1
4484179
Ceramic Disc Capacitor, 100 pF
×4
Panasonic eca2am220 image
Capacitor 22 µF
×4
PC817C
×4
DIP-16 bed
×2
ULN2003APG
×2
7805 case TO-220
×1
2n2222
×1
SMIH-12VDC-SL-C
×2
SRD-12VDC-SL-C
×3
TTL_485_MODULE_8PIN
×1
KF128 2.54_screw_3P
×1
KF128 2.54_screw_12P
×2
KF128 3.81_screw_2P
×7
KF128 5.08_screw_2P
×3
2.54_legs_female_2P
×1
2.54_legs_female_3P
×1
2.54_legs_female_4P
×2
2.54_legs_female_12P
×2
2.54_male_pins_40
×1
LED-2*5*7
×5
momentary switch 6x6x2
×3
1602 LCD with i2c interface
×1
Adafruit industries ada1536 image
Buzzer
×1
Ed01 09 0049 a 600x6001  23921.1539128511
Maxim Integrated DS18B20 Programmable Resolution 1-Wire Digital Thermometer
×6
usb→uart
×1
current sensor sct-013-000
×1

About this project

CHPC: Cheap Heat Pump Controller v1.x

The CHPC is 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.

Real life installation:

Works from ground heat collectors (loops) to radiant in-floor heating systems.

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.

Controlled via both RS-485 and 16x2 display with buttons.

Photos:

Change log:

17 May, 2019: PCB 1.3 tested, assembly instructions added.

  • 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.

Applications:

1. Thermostat

Brief: Precision thermostat. Simple and cheap. Only 1 relay and 1 temperature sensor required.Application examples: Room heat control. Chicken coop climate control. Distillation column. Else.

2. Heat pump (HP) controller

Brief: Heat pump controller. 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.

3. EEV controller

Brief: EEV driver, no relays. Requires 2 T sensors. Application examples: Upgrade your system from capilary tube to EEV. Available protections: Protects from liquid at suction line by design.

For more information about heat pumps look at Wikipedia about HP.

Features:

Takes care of system components health

  • 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
  • RS-485 or Serial (UART 5V) support
  • Automatically turns on/of system when heating required

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.

Example: day/night setpoint control and data visualisation with "pythonic rs485" way

Relays:

"Thermostat:"

Only 1 relay: drives electric heater (any)

"Heat pump" capillary tube, TXV, EEV:

5 relays, drives all you need:

4-way Valve (support coming up: autumn 2019)

  • 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)

Temperature sensors:

3 sensors needed for "HP with EEV" (absolute minimum scheme)

  • 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"

Temperature sensors installation example (medium scheme):

Get your own CHPC:

Somephotos, older revisions and prototypes:

PCB v1.1

EEV development started here.

Prototype 1. History, but worked well for a season.

More info and sources here: https://github.com/gonzho000/chpc

Author:

gonzho АТ web.de (c) 2018-2019

If you have any comments or questions, please do not hesitate to contact me.

Code

Github
https://github.com/gonzho000/chpc

Custom parts and enclosures

PCB Gerber file
PCB gerber, but look actual version at github
gerber_hp_v1_enVJAMy3SM.zip

Schematics

Scematics

Comments

Similar projects you might like

Making a Cheap Aquarium Parameters Controller

Project tutorial by Boisse Martin

  • 6,560 views
  • 3 comments
  • 19 respects

Soldering Iron Controller for Hakko 907

Project tutorial by Alexander

  • 33,252 views
  • 22 comments
  • 71 respects

Scorbot ER-V+ Controller & Simulator Design

Project tutorial by Amit Nandi (BigWiz)

  • 485 views
  • 2 comments
  • 5 respects

Soldering Iron Controller for Hakko 907 v.2

Project tutorial by Alexander

  • 24,566 views
  • 169 comments
  • 62 respects

Circuito Arduino Controller Pad

Project tutorial by AhmedAzouz

  • 3,459 views
  • 1 comment
  • 9 respects

Pool Controller

Project tutorial by Mike Mackes

  • 54,193 views
  • 43 comments
  • 124 respects
Add projectSign up / Login