Daikin EWYQ-BAWP handleiding
Handleiding
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EWAQ016~064BAW + EWYQ016~064BAW
Packaged air-cooled water chiller
4PW70082-1E – 2016.12
Installation and operation manual
10
8.9.2. Checking the water volume and expansion
vessel pre-pressure
The unit is equipped with an expansion vessel of 12 litre which has a
default pre-pressure of 1 bar.
To assure proper operation of the unit, the pre-pressure of the
expansion vessel might need to be adjusted and the minimum and
maximum water volume must be checked.
1 Check that the minimum total water volume in the installation,
excluding the internal water volume of the unit, is according to
the table.
Refer to "Technical specifications" on page 3 to know the
internal water volume of the unit.
Example:
To illustrate the impact on the system when modifying the setting
[F-00] we will consider the unit EWAQ064 (cooling only) which has a
minimum permissible water volume of 66 l. The unit is installed 5 m
below the highest point in the water circuit and is charged with 30% of
ethylene glycol.
Assuming that the setting [F-00] is changed from 5°C (default value)
to 0°C. From the below table we see that 5°C corresponds to a
temperature differential of 3,5 K and 0°C to 1 K, which is actually the
lowest value we can set.
The water volume correction factor according to the curve shown in
the below graph is 3.5; this means that the minimum volume will be
3.5 times larger.
Correction factor curve for minimum water volume
When multiplying 64 l by the correction factor, we get 224 l,
which will be the minimum water volume allowed in the
installation if a temperature differential of 1 K is used.
Now it is very important to check that for the height difference of
the system, the volume in the system is less than the maximum
allowed value at that pre-pressure (Pg). If we take a look at the
ethylene glycol concentration curve of 30%, for 1 bar of pre-
pressure the maximum volume allowed is 240 l.
The total volume in the system will definitely be larger after
adding the internal volume of the unit. In this case, some pre-
pressure can be applied or an additional expansion vessel or
buffer tank has to be installed in the field piping.
2 Calculating the pre-pressure of the expansion vessel
The pre-pressure (Pg) to be set depends on the maximum
installation height difference (H). This is the difference between
the highest point in the system and the unit [m], and is calculated
as below:
Pg=(H/10+0.3) bar
3 Checking the maximum allowed water volume
To determine the maximum allowed water volume in the entire
circuit, proceed as follows:
1 Determine for the calculated pre-pressure (Pg) the
corresponding maximum water volume using the graph
below.
2 Check that the total water volume in the entire water circuit is
lower than this value.
If this is not the case, the expansion vessel inside the unit is too
small for the installation. Solution: Install an additional expansion
vessel in the field piping.
EWAQ
(cooling only)
Minimum total
water volume
(l)
EWYQ
(heat pump)
Minimum total
water volume
(l)
016 33 016 76
021 33 021 76
025 33 025 76
032 33 032 110
040 66 040 152
050 66 050 152
064 66 064 220
INFORMATION
In most applications this minimum water volume will have a
satisfying result.
In critical processes or in rooms with a high heat load,
though, extra water volume might be required.
INFORMATION
The implementation of the new controller will allow the
modification of the temperature step difference through the
settings [A-02] and [F-00], which used to be fixed in the old
version. This has an impact on the minimum water volume
required when the unit operates in cooling.
By default, the unit is set to have a water temperature
difference of 3.5 K which allows it to operate with the
minimum volume mentioned in the previous table.
However, if a smaller temperature differential is set, as in
the case of process cooling applications where the
temperature fluctuations have to be avoided, a larger
minimum water volume will be required.
To ensure the proper operation of the unit when changing
the values of the setting [F-00] (for cooling mode), the
minimum water volume has to be corrected. It is very
important that this volume is within the range allowed in the
unit, otherwise an additional expansion vessel or a buffer
tank has to be installed in the field piping.
[F-00] values (°C) Temperature differential [K]
01
11.5
22
32.5
43
53.5
64
74.5
85
95.5
10 6
11 6.5
12 7
13 7.5
14 8
15 8.5
Water volume correction factor = Water volume correction factor
Temperature differential [K] = Temperature differential [K]
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5
9
Temperature differential [K]
Water volume correction factor
Temperature differential [K]
4PWEN70082-1E_2016_12.book Page 10 Wednesday, December 7, 2016 2:18 PM
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Productinformatie
| Merk | Daikin |
| Model | EWYQ-BAWP |
| Categorie | Niet gecategoriseerd |
| Taal | Nederlands |
| Grootte | 9272 MB |
