buletinul institutului politehnic din iaşi - Universitatea Tehnică ...

Nr.
test
Bul. Inst. Polit. Iaşi, t. LVIII (LXII), f. 4, 2012 75
Table 2
Results of the test with vapour injection
Set points Experimental results without injection
P su ΔT SI Pex ΔT sub π t ex;cp
M cd
& cp W& Φcd Φ0 COPheat
bar K bar K C kg/s kW kW kW
1 2 5 17 2 8.50 102.20 0.070 6.67 16.23 10.2 2.43
2 2 6 20 2 10.00 107.60 0.080 7.51 17.72 10.9 2.36
3 3 9 12 3 4.00 81.14 0.087 5.60 21.04 15.6 3.76
4 4 5 12 2 3.00 67.22 0.119 5.77 26.69 21 4.62
5 5 3 14 2 2.80 65.89 0.140 6.38 29.90 23.8 4.69
6 5 5 17 3 3.40 74.23 0.161 7.56 32.78 25.7 4.33
7 6 11 19 4 3.17 84.88 0.181 8.63 36.84 28.8 4.27
Nr.
Test
Table 2 (continued)
Results of the test with vapour injection
Set points Experimental results without injection
Psu ΔTSI Pex ΔTsub π inj M& Pinj tinj;cp COPcool εs εv bar K bar K kg/s bar C
1 2 5 17 2 8.50 0.027 4.4 2.9 1.53 0.52 0.76
2 2 6 20 2 10.00 0.024 4.71 7.7 1.44 0.55 0.78
3 3 9 12 3 4.00 0.02 4.82 20 2.79 0.56 0.81
4 4 5 12 2 3.00 0.01 5.69 8.7 3.63 0.58 0.85
5 5 3 14 2 2.80 0.011 6.68 15 3.73 0.58 0.84
6 5 5 17 3 3.40 0.012 7.58 19 3.39 0.61 0.86
7 6 11 19 4 3.17 0.015 8.81 26 3.34 0.62 0.87
In the above Tables, P, p – pressure (bar), T – temperature (K), t – temperature
(ºC), COP –performance coefficient (-), M& – mass flow rate (kg/s), W & –
compressor power (kW), Φ – capacity (kW), ε – compressor efficiency (-), ΔTSI
– superheating temperature difference (K), ΔTsub – subcooling temperature
difference (K), π – pressure ratio (-), su –supply, ex – exhaust, inj – injection
point, cp –compressor, s – isentropic compression, v – isochor compression, cd
– condensing point, 0 – evaporating point.
The same phenomenon happens for the compressor exhausted
temperature. The discharge temperature increases very slightly up to 9%. After
this point the discharge temperature starts to decrease, as it can be seen from