INSTALLATION
CHILLER-IOM-2004-E
17
4.7.
Desuperheater option (NEOSYS only)
The aim of the desuperheater is to recover high temperature heat from the compressor discharge gases by means of a heat exchanger
and without condensing. This point is important because in this case, no refrigerant receiver to compensate the volume difference between
the gas and liquid phase is then required. Therefore, we recommend mounting a regulating device on the water outlet temperature of the
desuperheaters to avoid condensing in the heat exchangers. The heat recovery capacity depends on the operating conditions (the
compressor discharge temperature comes from the HP/LP ratio), on the number of compressor running, on the water flow and on the water
inlet temperature.
The simplest regulation we recommend is the one on the scheme below: a 3-way valve with a regulation on the desuperheater water outlet
temperature (DOT). For instance, with 50/55°C operating conditions: if DOT>50°C, full flow through the desuperheater. If DOT<40°C, a
minimum flow below roughly 1/5th of the nominal flow versus operating conditions of the selection table. A better regulation can be achieved
by using an inverter driven pump that adjusts the flow to maintain the desired DOT.
Total heat
recovery
(at 50/55°C)
Total flow
(at 50/55°C)
Pressure
drop
(at 50/55°C
)
Total heat
recovery
(at 55/60°C)
Total flow
(at 55/60°C)
Pressure
drop
(at 50/55°C
)
Total heat
recovery
(at 50/55°C)
Total flow
(at 50/55°C)
Pressure
drop
(at 50/55°C
)
NAC 200
41
7,18
6
32
5,62
4
37
3,26
2
NAC 230
52
9,11
9
43
7,55
6
48
4,22
2
NAC 270
56
9,81
7
44
7,73
8
50
4,40
2
NAC 300
65
11,4
9
52
9,13
6
59
5,19
2
NAC 340
79
13,8
10
64
11,2
6
72
6,34
2
NAC 380
101
17,7
14
83
14,6
10
93
8,18
3
NAC 420
91
15,9
9
73
12,8
6
82
7,22
2
NAC 480
106
18,6
12
86
15,1
8
96
8,45
3
NAC 540
143
25,1
15
118
20,7
11
129
11,4
4
NAC 600
150
26,3
13
122
21,4
9
136
12,0
3
NAC 640
154
27,1
13
125
22,1
9
139
12,3
3
NAH 200
41
7,18
6
32
5,62
4
37
3,26
2
NAH 230
52
9,11
9
43
7,55
6
48
4,22
2
NAH 270
56
9,81
7
44
7,73
5
50
4,40
2
NAH 300
65
11,4
9
52
9,13
6
59
5,19
2
Note: there are 2 superheaters, so the flow per desuperheater is half of the total flow form the table
Unit boundary