Results 51 to 63 of 63
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10-09-2011, 01:46 PM #51
Re: Air Source Heat Pump Buffer Vessel Sizing
MadFridgie -in fact the Mad is wrong chosen in your case - inverters are in split systems (ceiling, wall, ground..) the only setup which will eliminate most complaints about cold drafts. The thermal comfort is much better because the sensible heat is higher once at operating conditions. But that's perhaps what you meant with 'forced draft exchangers'
It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.
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10-09-2011, 04:39 PM #52
Re: Air Source Heat Pump Buffer Vessel Sizing
This forum is probably the closest thing we have to a survey of systems and their problems/attributes. I would like to see if there could be a proper survey of complaints and solutions to see how much of a problem "bufferless" air to liquid systems are. The problem is that happy people don't complain so how would we design such a survey and get a reasonable sample size?
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10-09-2011, 04:55 PM #53
Re: Air Source Heat Pump Buffer Vessel Sizing
Haven't read the whole thread, just on post 9. Perhaps someone responded but what you calculated is if you do it in 14 hour. If you want to do this in 7 minutes, you will need +/- 1.7 kW( not calculated it right now) And 2 kg ice on coils is a lot if you ask me.
Then the heat isn't coming all from the indoor: the motor windings are hot when you start your defrost, so a lot of heat will come from the windings. This is how the simple defrosts work on small icemakers, domestics,....It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.
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10-09-2011, 05:11 PM #54
Re: Air Source Heat Pump Buffer Vessel Sizing
It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.
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10-09-2011, 05:14 PM #55
Re: Air Source Heat Pump Buffer Vessel Sizing
If you speed down an inverter compressor while heating, still connected to the same evaporator, then SST will rise and this will increase COP.Something which isn't possible with a fixed speed.
If your smallest capacity step matches the smallest needed heating capacity, then you don't need a buffer. We never install one on an inverter one.It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.
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10-09-2011, 05:17 PM #56
Re: Air Source Heat Pump Buffer Vessel Sizing
Then look once to this site www.liveheatpump.be I don't have any connections with this brand but as a technician, I like the way how they prove figures, not being afraid that the figures will turn against them.
It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.
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10-09-2011, 05:21 PM #57
Re: Air Source Heat Pump Buffer Vessel Sizing
It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.
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10-09-2011, 05:28 PM #58
Re: Air Source Heat Pump Buffer Vessel Sizing
It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.
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10-09-2011, 10:38 PM #59
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11-09-2011, 10:59 AM #60
Re: Air Source Heat Pump Buffer Vessel Sizing
Sometimes difficult to understand technical issues in another language. The term 'forced draft exchangers' was something which I struggled with.
I agree completely with you that inverters are somehow useless in a static system.
The only advantage could be that the radiant heating is proportionally controlled with the outdoor temperature as the driven parameter (and some fuzzy logically predicting what needs to be preheated when past temperatures are known) So you could make 'colder warm water' at a lower speed with the same coil outside, increasing SST when the water doesn't need to be that hot.
Anyway, we install often DX/water heatpumps and we rarely use a VFD on the compressors for the reason you gave. We installed a year ago a VFD on the DX/water of a friend , very interested in controls and heatpumps and he's following this for us. What he does is reducing the speed manually when outside temperature increases so that the compressors runs longer at an elevated SST. He has an hour meter on it and he can read the kW the VFD is pulling at that moment. A kWh meter should be even better and perhaps we will install this on his system. The VFD costs him nothing because the Government is paying 90% of he costs for a VFD on a compressor.It's better to keep your mouth shut and give the impression that you're stupid than to open it and remove all doubt.
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11-09-2011, 03:28 PM #61
Re: Air Source Heat Pump Buffer Vessel Sizing
If the World did not Suck, We would all fall off !
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11-09-2011, 04:09 PM #62
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11-09-2011, 04:34 PM #63