Thanks randen for enlighten me, you are so right about plate heat exchangers as I ve also read on some romanian documentation which I ve found on google and it was amazing well done and made me understand a lot about the realities of these systems ... Anyway as you also spoke about the costs of the homemade version vs commercial units I realized that I never looked again for local prices for geothermal heat pumps as I already knew since a lot of years ago that they are huge in Romania. There is no second hand market for heat pumps here ... apparently no one needs to sell suck a think as its a pretty new technology here. Anyway, apparently the cheapest water to water unit here that is 13.6 KW in power output is about ......wait for it.....
9184 USD (39.268 RON in Romanian currency)
here is the unit:
POMPE DE CALDURA APA-APA VIESSMANN VITOCAL 300-G tip WW 13.6 kW - CALOR
scroll down a bit the page and you see a photo whith the inside of it and they are plate heat exchangers .... I though W*F how can they sell that at that price ???? I also don t understand how that unit is weight 152 KG (335 pounds) .... can someone explain me that .... i don t understand... the case of the unit is made out of lead or those heat exchangers are something else maybe gold bars ???
If those heat exchangers are the same thing with what you used and the Wiltech one I ve shown you and they are 3-4 kg heavy the whole unit should be maybe 15.2 Kg not 152 Kg heavy and thats 10 times less than how much they say it weight.
Than I have found another unit on the local market in the same huge price range:
https://www.ferroli.ro/media/pdf/Man...nic_HXW_EN.pdf
There is a lot of data inside there , take a deep look
They say that they are using "stainless steel
brazed plates" with water volume 2,56 Liters , so I ve search at Wiltech for a similar unit with 2,5 Liters of water inside and I ve found this 7.5 KG heavy steel brick which is 270 USD :
WilTec - Plattenwärmeübertrager | PWT | Solar | BHKW | Edelstahl Wärmetauscher 50 Platten Plattenwärmetauscher max. 285 kW 50683
I guess the "stainless steel brazed plates heat echangers" are much better than cooper ones for the well water because cooper is reacting with water. Using stainless steel plate heat exchangers I guess I will still have to unscrew the water lines from it from time to time (a reasonable amount I HOPE ... like 1-2 times in a winter at most ) and do some kind of chemical flush or ultrasounds or combined or something else
I really need more info on this, please help