If the line started at say -15C that would determine the mass flow in the low side evaporator to be not so much larger than the high side evaporator. This will determine a much larger mass flow in the low side evaporator than in the high side evaporator. You then get a short segment of line to the right of the compressor suction where it connects with the vertical line from B2.
Start the compressor line somewhere between -23C and the rightmost end of the low side evaporator line. That is if you have say 7C superheat on the low side evaporator, this will give an evaporator outlet of -23C. The start point for the compressor suction shall be somewhere on the superheated part on the low side evaporator line.
Then draw an exactly vertical line down from B2.ĭraw the low side evaporator line to the right where it intersects with the vertical line from B2. If you hav been given a B2 temp, then use this temp for the B2 point. The compressor suction temperature may be roughly somewhere between the low temp evaporator outlet and the high temp evaporator outlet depending on the relative flow rate between thse two evaporators.
Dont care on what temperatures you have been given except if you have been given an outlet temp for the high side evaporator. If it's not then you are violating physical laws. I think i have it right but i want to be sure. I think i have it, could you show me what it should look like like on a ph chart possibly ( i know it's a big ask) because this isn't what i have been taught today at college. Now draw the compressor line and conect it to the right end of the condenser line and you are done. If the mass flow is equal in the low and high evaporator then this point is roughly on the middle on this short line. The start line for the compressor suction is somewhere on this short horizontal line and exactly where depends on the mass flow ratio between the low pressure and the high pressure evaporator. Draw a short horizontal line to connect this newly drawn vertical line with the right end of the evaporator line for the low pressure evaporator. This vertical line express the suction pressure regulator for the high pressure evaporator. Then draw a vertical line from the right end of the high pressure evaporator line and down to the pressure line for the low pressure evaporator. When this is done draw the evaporator line for the high pressure evaporator, connect the left end of this line to the vertical line expressing the exv at the low pressure evaporator, draw the right end of this line to where it meets the temperature line for the evaporator outlet at correct superheat. Well, this solution gives a system with a horrible efficiencyīut to draw this system, start with the low pressure evaporator and draw this complete system with the condenser, but leave the line for the compressor at this point.
No the evap pressures are different -10 and -40 with an EPGWell, this solution gives a system with a horrible efficiencyīut to draw this system, start with the low pressure evaporator and draw this complete system with the condenser, but leave the line for the compressor at this point.