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Cold weather performance of air sourced heat pumps

FlyWheel
Any heat pump experts on here? I’m looking at air sourced heat pump performance for a friend’s installation. They have NIBE F2040’s for the house, and Waterco Ultra 31’s for pool. Both use same R410A refrigerant, but that seem to be perhaps the only thing in common. NIBE (made in Sweden) twin rotary variable speed compressors are inverter controlled as standard (I guess vector or torque type drives), whilst the Waterco units are direct on line, capacitor start induction motors (I thought that technology went out long ago), with no soft start options.
 I’m interested in COP performance in the colder weather, the Ultra 31’s are specified as generally for use in ambient greater than 10 degrees C, although they do rate this particular model down to zero, BUT do not provide COP performance below 5 ambient, but enquiries suggest a COP of around 1 (perhaps even lower, ie, less power out than in!). The NIBE manufactures claim very much better, performance down to at least -25 ambient, with COP of around 2 even at this low temperature (is that even possible?).
Anyway, any thoughts on the subject, much appreciated.

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  • 0
    My dear friend John, 

    I explain the principle of operation and for that you need to know physics (we are in a professional association and I hope you understand me), how a heat pump works At any temperature exceeding minus 273 degrees C, there is heat in the air, the pump knows how to extract the heat from the air at any temperature and transfer it to a desired location. Also, these pumps take advantage of the natural air feature to balance by moving hot air to colder places. On the other hand, using a small amount of energy the heat pump makes this process, by injecting heat from the cold air outside the interior of the house more hotter. To do this, water, pumps, compressors and piping are used. The outside air comes in contact with water-filled pipes with a lower temperature than the air, which is constantly moving inside them by means of a pump. As a result, the air is drawn to the cold water in the cold pipe. Subsequently, the water is heated and transformed into a gas that passes through a compressor that compresses the gas, helping it to warm up. The heated gas works its way through the piping until it is a heat exchanger, which comes in contact with the house's water piping and greenhouse. This causes the gas to cool and return to the liquid that makes its way out again and then back again.  

    In summary I'm sorry you don't understand physics (because the post you uploaded is not at all related to hot weather). I would also love to have a deeper understanding of heat with a mathematical formula. have a good day.

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  • 0
    My dear friend John, 

    I explain the principle of operation and for that you need to know physics (we are in a professional association and I hope you understand me), how a heat pump works At any temperature exceeding minus 273 degrees C, there is heat in the air, the pump knows how to extract the heat from the air at any temperature and transfer it to a desired location. Also, these pumps take advantage of the natural air feature to balance by moving hot air to colder places. On the other hand, using a small amount of energy the heat pump makes this process, by injecting heat from the cold air outside the interior of the house more hotter. To do this, water, pumps, compressors and piping are used. The outside air comes in contact with water-filled pipes with a lower temperature than the air, which is constantly moving inside them by means of a pump. As a result, the air is drawn to the cold water in the cold pipe. Subsequently, the water is heated and transformed into a gas that passes through a compressor that compresses the gas, helping it to warm up. The heated gas works its way through the piping until it is a heat exchanger, which comes in contact with the house's water piping and greenhouse. This causes the gas to cool and return to the liquid that makes its way out again and then back again.  

    In summary I'm sorry you don't understand physics (because the post you uploaded is not at all related to hot weather). I would also love to have a deeper understanding of heat with a mathematical formula. have a good day.

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