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Old 10-21-20, 01:51 PM   #1
Lurking Renovator
Join Date: Mar 2013
Location: Oradea
Posts: 21
Thanks: 6
Thanked 4 Times in 2 Posts
Wink Inverter Ac converting into air-water heat pump

My current setup is an 24000btu R22 external unit.
This is heating my 1000L plastic tank once a day, which is insulated with 10cm of extruded polystyrene. Inside the tank I have 10mm copper tube/ 20m for heat transfer.
To have the best efficiency I programmed to start the pump once at 2PM when the outside temperature is the highest.

In the summer 20min of running heating the tank for 24 hours need.
In the winter if the temperature is dropping to 5degC it runing 1, 5 to 2 hours. Under 5 C I need to heat with an electric heater.

Now I want to improve something and extend it to house heating too, not just hot water.

I want to change the external unit with an inverter one.
The idea is simple, not so simple to do it.

I have 2 options:
1. Buy a new heat pump - no fun, spending lot of money
2. Converting an inverter AC unit - lot of chalanges, price is almost 10th of the new one + time spent for fine tuning. I have this idea from long time ago.

I have some knolege about automations, so I can jump in.
My passive house need is 5kW thermal heat, I guess one 18k unit will be fine. This thread can be used for bigger needs.

The chalange:
1. Install the external unit- easy
2. Connect the coil or one heat exchanger to the unit - easy. I prefer heat exchanger.
3. Controller setup
A. Use the indoor PCB and find a way how to cheat to have the needed control of the outside unit
B. Learn how to send specific command to the outdoor unit and build a simple arm based controller
C. Maybe sombody did it an I don't know
D. Buy a ready-made controller with 0-10V input - tried to search but hard to choose

Now I'm writing from the phone, I will put pictures of actual setup later. I will have more updates.

Have a nice day

ferox is offline   Reply With Quote