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Hey there guys pulled here from the engineering mindset calm now in the last video we looked at the basics of how a heat pump system works but in this video we're going to take a much deeper look we're going to be looking at how the pressure temperature enthalpy and entropy changes throughout the system as the refrigerant passes around between the main components of the compressor that condenser the expansion valve and the evaporator now I know some of you watches engineers out there and you're really keen to get hold of some numbers so don't worry we've got all the full numbers coming up as well I just want to point out that the numbers shown in this video may not represent the heat pump that you have in your buildings or that your server seeing etc these are purely as an example just to help you understand.
what's happening throughout the system so you shouldn't compare your figures against this system instead you should check with the manufacturer specifically for your heat pump and ask them and compare it against their design data all right so let's jump in so here we go we've got the the two different heat pumps they're in different modes we've got the heating mode and the cooling mode and you can see them pay attention to the evaporator and the condenser notice how on the heating mode I've labeled it there as well that the evaporator is on the outside whereas the condenser is on the inside and in the cooling mode the condensers on the outside and the evaporator is on the inside this is very important for the operation of the heat pump now just put up a schematic representation of this circuit and so in both circumstances the refrigerant is passing from the compressor compressor is there and it's passing around to the condenser see this one here you condenser here and also the condenser here then the refrigerant is passing through over to the expansion valve so after its passed really condenser in the heating mode passes to here to the expansion valve on the cooling mode after it leaves and goes freely condenser it passes through up into the expansion out there then you can see it comes round from the expansion valve to the evaporator so the expansion valve and then through the evaporator and on this slide for the expansion valve through the evaporator and then it goes lastly from the evaporator back to the compressor so from the evaporator background to the compressor same on this one from the evaporator background into the compressor and if you drew this out together properties with a temperature entropy and pressure enthalpy chart then this is the you know a simplified version of that profile so I've just marked out there up on the screen so you can now see all the different points so point one between the evaporator and the compressor you can also see that there on both the charts and then you can see the corresponding point on both the cooling mode and also the heating mode as obviously that point changes as the refrigerant is changing flowing directionally now the second point here which is between the compressor and the condenser again on the top right corner of the TS and pH charts and you can see on the heating mode that's just there
Before the condenser and on the cooling mode that's also just before the condenser same as it says there point 3 which is on the top left of the TS and pH charts and on the heating mode that is just here before the expansion valve as well as here just before the expansion valve on the indoor evaporator and lastly point 4 which is between the expansion valve and the evaporator again bottom left and on both the charts and point 4 here is just after the expansion valve before the evaporator same on the cooling mode so now we can see that all the points what the stage is going to be of the refrigerant so stage point 1 then the refrigerant will be a low-pressure low-temperature saturated vapor point two we know the refrigerants going to be a high-pressure high-temperature superheated vapor at point three we notice it's now going to be a high-pressure medium temperature saturated liquid at a point four we know this is now going to be a low-pressure low-temperature liquid vapor mix and that's going to make its way back to point one so here we are the goodies the numbers so a point one will start from here so it's a low-pressure low-temperature saturated vapor so we start off with a temperature here about two point five degrees Celsius thirty six degrees Fahrenheit and it's got a pressure of two hundred and sixty kilo Pascal's at two point six bar the entropy and see I'll put the letters down here so you know what they all are the entropy is non point nine kilojoules per kilogram per Kelvin or low point four five BTUs per pound by Fahrenheit and the enthalpy is going to be two four six kilojoules per kilogram 105 BTUs per pound now point two we can see from the charts we know it's going to increase in temperature we know it's going to increase in pressure it's also going to be some increase in the enthalpy as well so.
Bergvärme Stockholm: www.xn--bergvrmeistockholm-ptb.se
You can see here there we go well see the compressor so that pressure is going up as it compresses so the pressure has raised to 1600 kPa 16 bar that results in the temperature of 63 degrees Celsius 149 degrees Fahrenheit the entropy is going to remain roughly the same but the enthalpy will have increased as well so that's now 282 kilojoules per kilogram or 121 BTUs per pound now at point three there's going to be some reduction in heat and also there's going to be a pressure drop because obviously there's a lot of pipe work and bends in here so this will be some resistance to the flow of refrigerant so as the pressure drops and you can see there's going to be a drop in entropy and enthalpy so we've run now from 63 to 56 degrees Celsius hundred thirty-three degrees Fahrenheit the pressure you can see there's a small reduction in pressure there 50 kPa down to just half a bar the entropy has also reduced it's almost hard to ignore point four six kilojoules per kilogram per Kelvin and 0.11 BTUs per pound per Fahrenheit and then the enthalpy has also dropped from 280 to tu-134 kilojoules per kilogram 57 BTUs per pound now our point four you can see there's been a big drop in both pressure and temperature and that's because of the expansion valve now you will notice hopefully you'll have spotted that that entropy has actually increased slightly and that's because the gas has been expanded with a lick there was a liquid state there and now it's a liquid vapor mix it's been expanded there and when it expands the entropy increases but notice there is no change in enthalpy or they'll be very little you can see that.
We'd expect that on the chart there as well so that has now come down in temperature from 56 degrees Celsius down to minus or negative one hundred one point two three Celsius which is 29 degrees Fahrenheit the pressure has dropped back down to the same pressure here well close enough so 280 kPa two point eight bars the entropy has gone down to increase our eternal point five five kilojoules per kilogram per Kelvin which is equivalent to null point one three BTUs per pound per Fahrenheit and the enthalpy has remained the same at one three four kilojoules per kilogram 57 BTUs per pound so the refrigerant it will then make its way from point four back to point one passing through the evaporator and there you can see there is some increase in temperature there is also a slightly pressure drop and that again because of the resistance to the flow now I've put these as a different pressure drop compared to the above that's just the way it is it might even if you have the same coils that it's not necessarily going to be exactly the same pressure drop in real life in calculations yes but in real life no and then as you can see both the entropy and enthalpy increase back to their normal state or just this at state one so there we go that is the technical overview of how a heat pump works the numbers will be a bit different depending on if they are in heating or cooling mode and that's because you're obviously taking thermal energy either out of the building or into the building so the obviously the energy is different in the edge you have there but this is just an overview of how all these components work and what's happening in much in great detail amongst them so that is the end of this video thank you very much for watching I hope this has helped and hasn't confuse you too much please don't forget to Like subscribe and share and if you have any questions please leave them in the comment section below also don't forget to check out our website and once again thank you very much for watching
what's happening throughout the system so you shouldn't compare your figures against this system instead you should check with the manufacturer specifically for your heat pump and ask them and compare it against their design data all right so let's jump in so here we go we've got the the two different heat pumps they're in different modes we've got the heating mode and the cooling mode and you can see them pay attention to the evaporator and the condenser notice how on the heating mode I've labeled it there as well that the evaporator is on the outside whereas the condenser is on the inside and in the cooling mode the condensers on the outside and the evaporator is on the inside this is very important for the operation of the heat pump now just put up a schematic representation of this circuit and so in both circumstances the refrigerant is passing from the compressor compressor is there and it's passing around to the condenser see this one here you condenser here and also the condenser here then the refrigerant is passing through over to the expansion valve so after its passed really condenser in the heating mode passes to here to the expansion valve on the cooling mode after it leaves and goes freely condenser it passes through up into the expansion out there then you can see it comes round from the expansion valve to the evaporator so the expansion valve and then through the evaporator and on this slide for the expansion valve through the evaporator and then it goes lastly from the evaporator back to the compressor so from the evaporator background to the compressor same on this one from the evaporator background into the compressor and if you drew this out together properties with a temperature entropy and pressure enthalpy chart then this is the you know a simplified version of that profile so I've just marked out there up on the screen so you can now see all the different points so point one between the evaporator and the compressor you can also see that there on both the charts and then you can see the corresponding point on both the cooling mode and also the heating mode as obviously that point changes as the refrigerant is changing flowing directionally now the second point here which is between the compressor and the condenser again on the top right corner of the TS and pH charts and you can see on the heating mode that's just there
Before the condenser and on the cooling mode that's also just before the condenser same as it says there point 3 which is on the top left of the TS and pH charts and on the heating mode that is just here before the expansion valve as well as here just before the expansion valve on the indoor evaporator and lastly point 4 which is between the expansion valve and the evaporator again bottom left and on both the charts and point 4 here is just after the expansion valve before the evaporator same on the cooling mode so now we can see that all the points what the stage is going to be of the refrigerant so stage point 1 then the refrigerant will be a low-pressure low-temperature saturated vapor point two we know the refrigerants going to be a high-pressure high-temperature superheated vapor at point three we notice it's now going to be a high-pressure medium temperature saturated liquid at a point four we know this is now going to be a low-pressure low-temperature liquid vapor mix and that's going to make its way back to point one so here we are the goodies the numbers so a point one will start from here so it's a low-pressure low-temperature saturated vapor so we start off with a temperature here about two point five degrees Celsius thirty six degrees Fahrenheit and it's got a pressure of two hundred and sixty kilo Pascal's at two point six bar the entropy and see I'll put the letters down here so you know what they all are the entropy is non point nine kilojoules per kilogram per Kelvin or low point four five BTUs per pound by Fahrenheit and the enthalpy is going to be two four six kilojoules per kilogram 105 BTUs per pound now point two we can see from the charts we know it's going to increase in temperature we know it's going to increase in pressure it's also going to be some increase in the enthalpy as well so.
Bergvärme Stockholm: www.xn--bergvrmeistockholm-ptb.se
You can see here there we go well see the compressor so that pressure is going up as it compresses so the pressure has raised to 1600 kPa 16 bar that results in the temperature of 63 degrees Celsius 149 degrees Fahrenheit the entropy is going to remain roughly the same but the enthalpy will have increased as well so that's now 282 kilojoules per kilogram or 121 BTUs per pound now at point three there's going to be some reduction in heat and also there's going to be a pressure drop because obviously there's a lot of pipe work and bends in here so this will be some resistance to the flow of refrigerant so as the pressure drops and you can see there's going to be a drop in entropy and enthalpy so we've run now from 63 to 56 degrees Celsius hundred thirty-three degrees Fahrenheit the pressure you can see there's a small reduction in pressure there 50 kPa down to just half a bar the entropy has also reduced it's almost hard to ignore point four six kilojoules per kilogram per Kelvin and 0.11 BTUs per pound per Fahrenheit and then the enthalpy has also dropped from 280 to tu-134 kilojoules per kilogram 57 BTUs per pound now our point four you can see there's been a big drop in both pressure and temperature and that's because of the expansion valve now you will notice hopefully you'll have spotted that that entropy has actually increased slightly and that's because the gas has been expanded with a lick there was a liquid state there and now it's a liquid vapor mix it's been expanded there and when it expands the entropy increases but notice there is no change in enthalpy or they'll be very little you can see that.
We'd expect that on the chart there as well so that has now come down in temperature from 56 degrees Celsius down to minus or negative one hundred one point two three Celsius which is 29 degrees Fahrenheit the pressure has dropped back down to the same pressure here well close enough so 280 kPa two point eight bars the entropy has gone down to increase our eternal point five five kilojoules per kilogram per Kelvin which is equivalent to null point one three BTUs per pound per Fahrenheit and the enthalpy has remained the same at one three four kilojoules per kilogram 57 BTUs per pound so the refrigerant it will then make its way from point four back to point one passing through the evaporator and there you can see there is some increase in temperature there is also a slightly pressure drop and that again because of the resistance to the flow now I've put these as a different pressure drop compared to the above that's just the way it is it might even if you have the same coils that it's not necessarily going to be exactly the same pressure drop in real life in calculations yes but in real life no and then as you can see both the entropy and enthalpy increase back to their normal state or just this at state one so there we go that is the technical overview of how a heat pump works the numbers will be a bit different depending on if they are in heating or cooling mode and that's because you're obviously taking thermal energy either out of the building or into the building so the obviously the energy is different in the edge you have there but this is just an overview of how all these components work and what's happening in much in great detail amongst them so that is the end of this video thank you very much for watching I hope this has helped and hasn't confuse you too much please don't forget to Like subscribe and share and if you have any questions please leave them in the comment section below also don't forget to check out our website and once again thank you very much for watching