Heat Pump Defrost Cycle Explained

[@domba312]

It is worth to mention that Panasonic Heat Pump can use water from domestic hot water tank ( ili PTV na hrvatskom ) for defrosting.. There you have more than enough hot water to do defrost with less interference on heating. Anyway - its always good to have something form you Mario as we learning that way. thanks..

[@HVACEducationHub]

Thanks. Yes, forgot to mention that but I was speaking generally without specific manufacturer.

[@pavlemilenkovic1683]

Thank you for this video! Really informative, good job. 👏👏

[@HVACEducationHub]

Thanks!

[@JamesSmith-d2s]

Thank you for this lesson, it is very important and useful information. I learned a lot of new things.

[@HVACEducationHub]

Thank you

[@klpd666]

It is not only the system volume, it is the volume in combination with the temperature of the volume. If you have 300 litres at 10 degrees, it will not defrost your unit, or it will take a lot of time compared to 30 litres at 90 degrees for example. I run a 7KW Panasonic J series, The pump will use its 3 KW backup heater for a defrost cycle for 10 minuutes if the inlet water temperature is below 27 degrees. I have enough volume (about 80 litres) but the temperature is too low. On a humid day at around 2 degrees outside when the inlet temperature is arround 22 degrees, i can expect a defrost cycle every hour. That is 12 KW consumption on the backup heater alone in 24 hours! The house does stay warm, no problems there, however the COP drops like a rock. The hidden cost of running on low temperature.

[@HVACEducationHub]

Thank you for feedback, good to hear different perspectives. House that I showed in video has around 250 L of water for 12 kW and no problem with 25 C inlet temperature, 10 min defrost with compressor, backup heater never turned on.

[@klpd666]

@@HVACEducationHub Interesting. Is there any way i can get this to work with my 7J series as wel?

[@HVACEducationHub]

I think J generation (R32) could be better than H (R410A). But I didn’t mention that it is underfloor heating with really high thermal mass (300 m2). So it is different than volumiser.