Hiya,
Does anyone have a copy of this software with discharge temperature in it? Official version doesn't include this. The version copeland uses does!
It would be sooooo helpful.
I want a copy =)
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Hiya,
Does anyone have a copy of this software with discharge temperature in it? Official version doesn't include this. The version copeland uses does!
It would be sooooo helpful.
I want a copy =)
hi ,
I dont belive that there is such version. visit ecopeland.com for software updates on select 6.
rojer
Beleive me - there is. The version Copeland use. Our version is a bit slimmed down.
"Advanced" version should have found it's way out :)
Discharge temperature depends (among others) of power loss factor of each compressor and conditions of compressor surrounding (air speed, temperature, humidity, insolation ). How software can calculate this without asking user that data?Quote:
Originally Posted by Copman
Sure. You are right. But select calculates for COP, Power input, power output etc. These are parameters that are also effected by what you describe above.Quote:
Originally Posted by nike123
No fiquiers are 100% accurate, but you get a good idea of what you can expect.
If it is assumption, than you could do that with Coolpack!
Interesting subject with discharge temperature. I've done some hastily research on Dorin and Copeland selection software, semihermetics only. Copeland software states the "heat rejection", while Dorin states the "condenser heat". I assume them to mean the same thing.
I've run simulation on Dorin K1500CS and Copeland D4DF-100X. Evaporating/condensing -30C/+30C, R404a. Two simulations each, one with -25C suction and the other with +25C suction temperature.
The actual compressor heat loss must inevitably differ hugely between those two different suction gas temperatures as the compressor itself inevitably has to be much warmer with +25C suction compared to -25C suction.
When running two simulations in Coolpack with the input and result parameters I have in the two different Dorin software simulations, I have to select the heat loss factor in Coolpack to zero in order to get the same "condenser heat" value returned by Coolpack as I get in the Dorin software! This result, zero% compressor heat loss, might very well be correct with a suction temperature of -25C, but can no way be correct with a suction temperature of +25C.
In the Coolpack simulation of the Copeland compressor, I also have to specify an identical heat loss factor of 5% in both simulations, with -25C and +25C suction temperature, to acheive the correct "heat rejection" value stated by the selection software.
None of these selection softwares take into account the inevitable different compressor heat loss factor caused by varying suction gas temperatures!
I have experience with that particular Dorin compressor. The suction channels between the motor and the inlet valves cover a large part of the outside of the upper compressor body section. In addition the whole of the cylinder head is covered by suction channels except a small port in the center of each head where the discharge pipes is attached. This construction of the suction channels result in the outside of the compressor to be surprisingly cool. If the suction gas is cool, lets say -25C, then it is fully possible to have a negative compressor heat loss factor! It is absolutely unnessecarry with a cooling fan on these compressors when running at low suction temperatures as the plant room temperature is normally warmer than most of the surface of the compressor!
At 25C suction temperature, the surface of the compressor will be warmer, possibly considerably warmer, than 20/25C thus lead to a considerable heat loss.
Assuming a "normal" plant room temperature of, lets say 20/25C, then the heat loss factor for this compressor, as expressed by the "condenser heat" value returned by the Dorin selection software, should range from a small negative value at low suction gas temperature to a positive value of maybe 10 to 20% at 25C suction gas temperature. It does however not do this, the software calculates the heat loss factor to zero independent of the suction temperature.
The same shortcoming applyes to the Copeland selection software. The upper compressor body and the compressor head will be warmer at any condition due to different suction channel layout, both in the compressor body and in the cylinder head, on this Copeland compressor compared with the Dorin compressor. It is maybe not possible with negative heat loss factor, and the heat loss factor will be higher under equal operating conditions.The software calculates the heat loss factor to 5% independent of the suction temperature. This value might be accurate at some low suction temperatures, lets say -25C, but cant possibly be correct at lets say +25C suction.
The conclusion is that if the "in house" Copeland selection software has the same flawed equations to calculate the "heat rejection" value as the comercially available software has, then the discharge temperature returned by that "in house" software us without any value whatsoever.
With all energy calculations we have to make certain assumptions. We may use 36C in summer to base our calculations or 21C in colder climates. The result is a vastly different calculation. We may calculated an entering load at 5000kg when the actual load ends up at 3500 kg. We are also assuming the compressor capacity is accurate when it may be 5% to 10% out. The same with condenser and evaporator. I think its pointless to worry about the heat picked up by the refrigerant for the 0.2 seconds it is in the cylinder with all these other imponderables in the system and for the sake of sanity assume isentropic compression.
Heat rejection and discharge temperature are completely differnt things.
Heat rejection is power and measured in kW, temperature is measured in °C.
As nike123 said, you could input the outdata from Select6 (or 7) into coolpack and simulate the discharge temperature.
For asercom certified compressors, a more encompassing test run is available through ASERCOM/ASERVAL software (http://www.asercom.org) by looking at Emerson compressors.
This is correct assuming you know what the heat loss (factor) from the compressor is. And this is the shortcoming of the compressor manufacturers calculation software, the heat loss is a fixed percentage in the calculation software despite the real life heat loss differs hugely dependent on the operating conditions of the compressor. It can differ from a slightly negative value on some Dorin semihermetic compressors at some operating conditions to as much as maybe 20 percent on many other semihermetic compressors at different operating conditions. The only accurate statement that can be made is that the discharge gas temperature from a compressor thoroughly thermaly insulated against the ambient air will have a discharge gas temperature equal to that calculated by software like Coolpack when a heat loss factor of zero is entered into that software.Quote:
Originally Posted by NoNickName