Very informative seminar, though 21:46 I couldn't understand this part. * When temperature rises density goes down, as Mass Flow = Density*Velocity*Cross Section Area, mass flow should go down too. Why does it go up? I thought we should've *increased the coolant density* to increase the coolant capacity. * And how could the cooling capacity go up when the SST goes up and SDT stays the same? I thought more temperature difference between SST and SDT would increase the cooling capacity. (10:50 For people who didn't know about RLA, it's Rated Load Amps. It's the current when compressor works at rated power, also the current term for FLA.)
Great questions Ali. I am not an expert but When temperatures go up, mass flow goes up because the volume of refrigerant the compressor move. It can fit more gas into the chambers and move more gas.
Point one: - If you are referring to the compressor suction side your thoughts are on the right track but the premise is not. As the saturated suction/gas temperature rises so does the gas density, this is a thermodynamic property of the refrigerant. Cooling capacities increase when moving from left to the right of the table, so the cooling capacity is proportional to the SST. Point two: As the temperature difference between SDT and SST increases the cooling capacity decreases irrespective of which quantity (SST, SDT, or both) causes the increase. This is due to the increase in compression ratio, note that the capacity is inversely proportional to SDT and the compressor displacement volume can be considered constant.
You need to access the major compressor manufacture websites. Here are a few www.bitzer.de/websoftware/ webapps.emerson.com/online-product-information www.carlylecompressor.com/support/software/ www.danfoss.com/en/service-and-support/downloads/dcs/coolselector-2/ vap.bock.de/stationaryapplication/Pages/Index.aspx
@@RefrigerationMentor Thank you so much for your response but the product selection software of almost all of those(except for Copeland's) do not provide us with any information on efficiencies; neither isentropic nor volumetric. If you know where exactly should I search for such data please refer me to. Thanks a lot.
Thank you Trevor for this video. Design conditions are the conditions that I believe are the correct conditions for a specific application?
Thanks for sharing! Check out these refrigeration design videos offers.refrigerationmentor.com/micropipe
Very informative seminar, though 21:46 I couldn't understand this part.
* When temperature rises density goes down, as Mass Flow = Density*Velocity*Cross Section Area, mass flow should go down too. Why does it go up? I thought we should've *increased the coolant density* to increase the coolant capacity.
* And how could the cooling capacity go up when the SST goes up and SDT stays the same? I thought more temperature difference between SST and SDT would increase the cooling capacity.
(10:50 For people who didn't know about RLA, it's Rated Load Amps. It's the current when compressor works at rated power, also the current term for FLA.)
Great questions Ali. I am not an expert but When temperatures go up, mass flow goes up because the volume of refrigerant the compressor move. It can fit more gas into the chambers and move more gas.
Point one: - If you are referring to the compressor suction side your thoughts are on the right track but the premise is not. As the saturated suction/gas temperature rises so does the gas density, this is a thermodynamic property of the refrigerant. Cooling capacities increase when moving from left to the right of the table, so the cooling capacity is proportional to the SST.
Point two: As the temperature difference between SDT and SST increases the cooling capacity decreases irrespective of which quantity (SST, SDT, or both) causes the increase. This is due to the increase in compression ratio, note that the capacity is inversely proportional to SDT and the compressor displacement volume can be considered constant.
Thanks Trevor !! Really appreciate it .
You welcome Gurminder
Thank you Sir, this is Olson.
You are welcome Olson. What was the one thing you took away from the webinar that you believe will be helpful to you?
how to access to data like volumetric and isentropic efficiencies under different performance conditions?
You need to access the major compressor manufacture websites. Here are a few www.bitzer.de/websoftware/ webapps.emerson.com/online-product-information www.carlylecompressor.com/support/software/ www.danfoss.com/en/service-and-support/downloads/dcs/coolselector-2/ vap.bock.de/stationaryapplication/Pages/Index.aspx
@@RefrigerationMentor Thank you so much for your response but the product selection software of almost all of those(except for Copeland's) do not provide us with any information on efficiencies; neither isentropic nor volumetric. If you know where exactly should I search for such data please refer me to. Thanks a lot.
Oustanding
Thnaks