NANOOK - open source DIY 19kW GWHP
 

Hi community, I just want to share my successful built of 19kW ground-water heat pump. It’s completely open source, incl. calculations, chassis drawing, schematics and control software.
Anybody who wants to clone the construction is highly welcomed!

Here are some highlights:
- 19kW heating power
- 65°C / 149°F max. output temperature
- r134a refrigerant
- 950 meters ground loop
- easy to build
- 8 temperature sensors
- 4 pressure sensors
- 2 flow sensors
- EEV (with supercapacitor backed up closure on power failure)
- Panasonic/Sanyo scroll compressor
- soft starter
- 2 circulation pumps
- onboard control system running Linux
- configuration via web browser

Image gallery:
ownCloud

3D model:
https://cad.onshape.com/.../e/8527985f7e35e0cf1587fe34

KiCAD schematics and PCB on my Github:
https://github.com/burgrp?utf8=%E2%9...ype=&language=

Looking forward to see your comments!

few images...
 

few images, just for case the link above does not work

That’s beautiful! What kind of C.O.P are you getting?

Thanks. COP is not measured yet. The built-in pulse flow meter is working, but is not calibrated yet. As soon as I do calibration by another flow meter, I will let the software calculate COP and will post it here.

Pavel

I'm impressed. That is a beautiful job.!!! You have went the extra mile with controls. Soft start will be well worth the effort for a machine that size. We can compare notes with my 5 ton DIY

Randen

Hi Randen, I like your drum design :) I wish my NANOOK will be as reliable as your machine - 5 years in service, that's impressive!

Budget
 

Any idea of the total price of equipment and time to spend?

In terms of time, it was almost one year of development. Construction of the pump itself, when I had everything on table, took few days only, it went smooth, including refrigerant charging. In terms of money, the pump was about 2500 USD, collector 3500 USD.

Costs
 

What are the typical costs for producing energy now?
Mantainance eletricity etc...

Here in Czech Republic, I would spend at least 3000 USD per year for direct electric heating. So it's quite a good ROI - if that's what you are asking for.

Nice build, professional look

Can you comment a bit on your start-up and shutdown procedure?

There are three sequences controlled by the software:

START:
- turn both circulation pumps ON
- close EEV by 500 steps, open EEV by 150 steps
- ramp compressor SSR up from 50% to 100% in 800ms
- switch compressor coil relay ON
- switch compressor SSR OFF
https://github.com/burgrp/nanook-js/...r.js#L218-L243

STOP:
- switch compressor SSR ON
- switch compressor coil relay OFF
- switch compressor SSR OFF
- close EEV by 500 steps
- turn both circulation pumps OFF
https://github.com/burgrp/nanook-js/...r.js#L252-L280

MEASURE:
Is a simple sequence launched every 5minutes when HP turned off. It just turns output circulation pump ON for 30seconds, measures water temperature, and then turns the circulation pump OFF. This way there is no need for external temperature sensor.
https://github.com/burgrp/nanook-js/...r.js#L327-L338

looks like you have 3 speed-circulator pumps; Have you allready experimented with the speed of these pumps? I guess you could control the speed via 2 relays

It could be controlled, but it seems to be not necessary. The secondary side is switched to minimum which is enough to transport the heat to accumulator tank. The primary side is switched to maximum, while the temperature drop is a bit higher then it should be - so I probably need more powerful pump here.

Git repositories have been moved under DEVICE.FARM organization:
https://github.com/device-farm?utf8=...ype=&language=