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  1. Jon_Doe

    Differences between modern AC and air source heat pump compressors

    MSZ-HR (cheap unit) 2 datasheets with different kind of info: https://aerconditionatmitsubishi.ro/index.php?controller=attachment&id_attachment=334...
  2. Jon_Doe

    Differences between modern AC and air source heat pump compressors

    Thanks. I think i was a little unclear. I know the costs, i don't know the exact technologies inside each unit. For example. I found 2 Mitsubishi units with what seems to be like identical specs but one is twice the price. Now, i don't know if it's because of bling functions like wifi and noise...
  3. Jon_Doe

    Differences between modern AC and air source heat pump compressors

    Thank for all the feedback. Cooling is inherently more efficient than heating since the summertime cooling Delta T's are much smaller than wintertime heating delta T's. By design, i would only use the unit with outside air above freezing (A2W when outside is above freezing or geothermal which...
  4. Jon_Doe

    Differences between modern AC and air source heat pump compressors

    Hi all. I'm wondering, what are the major differences between an AC compressor and an air source heat pump compressor. Wen i say AC, i mean small, domestic, split units, not the large industrial ones. There are a few differences i noticed from studying datasheets but couldn't find more in...
  5. Jon_Doe

    Variable speed refrigerant compressor at very low speed - efficiency

    Thanks for the concern. I've done the calculations and there's no point in having heating turned off while away mainly due to inertia but also the efficiency of the system. Depending on the exact system and circumstance, it may be cheaper to run permanently at low power than having high power...
  6. Jon_Doe

    Variable speed refrigerant compressor at very low speed - efficiency

    Thanks for your inputs. I do want to design for max load but not neglect the minimum load. Power cycling is not an issue, taking into account the minimum duty cycle. On inverter driven units this is less of an issue due to soft starting and smooth gliding to the operating point of the...
  7. Jon_Doe

    Variable speed refrigerant compressor at very low speed - efficiency

    Ok, so i guess my original post was unclear. Yes, it's my residence. It was designed and built, by me, to get the max out of the available funds (which were rather low). It's a timber frame with 20" straw bale infill walls and 2ft of fiberglass in the attic (which is empty, non livable space)...
  8. Jon_Doe

    Variable speed refrigerant compressor at very low speed - efficiency

    Thanks for your input. My primary heating source atm is Propane LPG. It's half the price of electricity and twice of natural gas (not available in my area - no pipeline - maybe in 10 years - maybe). So, if i need / want, i can stick to Propane for all needs, for the peak heating load, for DHW...
  9. Jon_Doe

    Variable speed refrigerant compressor at very low speed - efficiency

    THanks for all the feedback. Prices are wild, 1kwh electric is ~ 4 times the price of 1kwh natural gas. The thing here is i only have electricity, no natural gas pipeline. Even with bottled propane lpg i still get half of natural electricity costs. An 9kbtu to 12kbtu A+++ ac is $600 or up to...
  10. Jon_Doe

    Variable speed refrigerant compressor at very low speed - efficiency

    Hi there. It's actually heating as it turns out after a year of use, there's almost no need for cooling. Therefore, we're talking about COP. By 2 x 50% systems, you mean run one from min to max, and when reaching max starting the second one also going from min to max ? That would mean even...
  11. Jon_Doe

    Variable speed refrigerant compressor at very low speed - efficiency

    Hi there everyone. I know variable speed compressors can be overdriven and also run very low. Some sources indicate down to 10% but most it's no less than 30%. What i could not really find out is data about efficiency of the system at very low speeds. The reason i'm pondering this is that i...

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