Hitachi YUTAKI M Bedienungsanleitung Seite 36

Drop in the delivery water temperature that the client is willing to allow in the installation.
Q = Heat loss during defrosting (kW)
DEF
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 = Heat demand from the installation (kW)
I
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 0°C WB and a delivery water temperature at, for example, 45°C.
Q = Cooling load on the YUTAKI M (kW)
Y
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: 6/7°C (WB/DB) and input/output temperature of the water: 40 / 45°C)

NOTE
The maximum time for defrosting considered is 6 minutes per hour.
The following table shows the minimum water volume needed in each unit.

NOTE
• The values shown on the table are based on theoretical installation conditions. In addition
YUTAKI units admits several hydraulic circuits configurations, 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.
PMEN0647 rev.0 - 11/2023
Water temperature drop
5°C
10°C
15°C
20°C
25°C
30°C
2 HP 3 HP
Volume (L)
212 212
106 106
71 71
53 53
42 42
36 36
5
28