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Old 07-26-15, 05:37 AM   #1
Acuario
Apprentice EcoRenovator
 
Join Date: May 2011
Location: Tortosa, Spain
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Default Combined solar + heatpump central heating/cooling

Anyone following my adventures will have seen the thread on our new build.
As a result the old boiler room where I had the heat pump/solar etc. was demolished and a new room built to house everything. This also meant a major re-plumbing/mounting/installing etc.... So mk2 was born with a few changes and to incorporate under floor heating/cooling..

Originally I had a home made heat exchanger with a 100L water tank to do the transfer between the heat pump and water system. A while back I experimented with a second unit connected to a small plate heat exchanger and was pretty happy with the results so when my home made hx developed a leak I decided it was time to move to a slightly larger plate hx.

This worked well over the winter and then in reverse mode was working well for cooling the water for the under floor cooling.

My only concern was that the hx was at one end of the boiler room and the heat pump at the other, resulting in some losses due to distance. So when a broken heat pump came my way I had the perfect solution - a huge plate hx with mount and flow sensor and as a bonus a filter dryer - ok, it was for R410A and I'm using R417A but with a bit of a clean all should work out well.



So I re-plumbed the piping to the heat pump, connected up to flow and return and all now works exceptionally well.



I've also installed a second heat pump connected to the original hx so I can give a boost on those few cold days we get in February.





I also re positioned the hot water panels I have for winter heating - they are connected to the 100L water tank in the picture. They are angled high to capture maximum sun in the winter - in the summer they aren't used and I empty them. The controller (not shown) is home made using a pic and has anti-freeze protection built into it just in case...



The picture of the collector set shows the temperature of the water going into the floor at 18 degrees, this just about coincides with the exit temperature from the hx.



The system is being run by an AIR-80 heat pump controller - this unfortunately only works for heating (so I have the 4-way valve set to cooling)but will do until I build my own controller. It works perfectly in the winter in heating mode as it has a hot gas defrost cycle as part of its program.



You can find these cheaply on AliExpress.



In the picture of the 'mess :-)' you can see the boiler which is connected as a back-up of last resort should a)The weather is too cold for the heat pumps or b)We have no grid power - we have 4Kw solar electric that will happily run the boiler and circulating pump. Also visible on the left is my latest project, the Fan-coil internal aircon unit which is just there for testing.

Acuario

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