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Firebird
Installation & Operation Manual
20
The following section shows how to calculate the minimum water
volume in the system for product protection (anti-hunting) and
temperature drop at defrosting.
1 Protective water volume for product. Ensure that the water
volume is equal or greater than those shown below, in order
to lower ON / OFF frequency of Enviroair unit at no load
or extreme light load. When water volume is less than the
volume indicated (minimum water volume), compressor
operation frequently stops at light load, which should result
in shorter life or failure.
NOTE
The factory default ON / OFF temperature differential is “4
°
C”.
Note that the minimum water volume varies for different setting
for each purpose as shown in the next table (unit: ltrs.):
Model
ON / OFF
temperature
differential
Enviroair
7kW
Enviroair
11kW
Enviroair
14kW
Enviroair
16kW
4ºC
28
38
46
56
3ºC
36
48
58
70
2ºC
50
65
80
96
1ºC
80
107
130
156
2 Minimum required water volume during defrosting
• The following formula is used to make the calculation:
Where:
V = Required water volume (m
3
)
The minimum volume of water needed in the installation to
cover the heat loss caused by a reduction in the delivery
water temperature during defrosting.
∆
T = Permissible water temperature drop (ºC)
Drop in the delivery water temperature that the client is
willing to allow in the installation.
Q
DEF
= Heat loss during defrosting (kW)
Heat loss caused in the system by reducing the delivery
water temperature, which may affect the user’s
comfort level of warmth. This value is the sum of
the two following items:
Q
I
= Heat demand from the installation (kW)
While defrosting is taking place, the unit is not providing the heat
required to cover the heat demand from the installation.
This value can be obtained in 2 ways:
1. By using the value of the energy demand from the installation,
if known.
2. If this value is not known, it can be estimated by using the
heating capacity of the unit at an air temperature of 0ºC WB
and a delivery water temperature at, for example, 45ºC.
QY = Cooling load on the Enviroair unit (kW)
In addition to not providing the heat required to cover the
heat demanded by the installation during defrosting, the unit
is also producing cold. It can be estimated that this value is
approximately 85% of the heating capacity on the unit under
standard conditions (air temperature: 6 / 7ºC (WB/DB) and input
/ output temperature of the water: 40 / 45 ºC).
NOTE
The maximum time for defrosting considered is 6 minutes
per hour.
The following table shows the minimum water volume needed
in each Enviroair unit in case of a permitted drop in temperature
of 10ºC (unit: ltrs.).
Model
Water
temperature
drop
Enviroair
7.5kW
Enviroair
11kW
Enviroair
14kW
Enviroair
16kW
5ºC
212
276
342
410
10ºC
106
138
171
205
15ºC
71
92
114
137
20ºC
53
69
86
103
25ºC
42
55
68
82
NOTE
• The values shown on the table are based on theoretical
installation conditions. In addition, Enviroair unit admits
several hydraulic circuits configurations (as shown in the
Manual of the system controller), and the value can be
different depending on each specific installation.
• Therefore, it rests with the client to recalculate these values
depending on the real conditions of the installation.
8.3 Minimum Water Volume Description
V =
360 x Q
DEF
; Q
DEF
= Q
I
+ Q
Y
∆
T x 4168.8
Содержание Enviroair 11kW
Страница 1: ...SUPERIOR HEATING SOLUTIONS SINCE 1980 Installation Operation Manual...
Страница 2: ...Firebird Installation Operation Manual 2...
Страница 9: ...9 5 General Dimensions Enviroair 11 16kW Enviroair 7 5kW 5 1 Service Space...
Страница 54: ...Firebird Installation Operation Manual 54 Notes...
Страница 55: ...55...