Cop and heat pumps speed control onoff.
Heat pumps are, as we all know, low temperature systems. By low temperature is meant a maximum of 50-55 degrees on supply on the coldest day of the year.
Cop and location
Today's heat pumps can perform a few degrees more at the expense of COP which is an abbreviation of Coefficient Of Performance, simply put, it can be described as efficiency, however, the word efficiency is actually banned, for efficiency can not be more than 1, but for the common man it is a word that most people understand the meaning of.
What then determines the cop In, for example, air water, it is the air temperature, the air flow rate and the temperature from the heat pump to the heating system.
Today's speed-controlled pumps are larger than ever, something that the lady of the house usually turns to when discussing a heat pump. But that's where we have our cop. When it gets colder outside, the energy in the air drops and to compensate for the energy loss in the air, the speed of the fan and even then of the compressor, which has a certain stroke volume, is increased. But as the speed increases, the flow of the refrigerant increases. And the effect is maintained further down in temperature.
To take an example.
Nibe 2120 with maximum power 12 kw gives at -18 as much as about 7 kw at 50 degrees supply temp. Fifteen years ago, the pumps were switched off at -7 / -10 depending on the brand in question. It was not considered profitable to operate below these temperatures. In today's pumps, the heat carrier pump is also speed-controlled and they usually control based on the so-called delta T, which means the difference between supply and return.
Heat pump techniques with or without limits.