11
Performance chart for the VUT 2000 WH-4 water heater parameters is shown in Fig. 9.
Fig. 9 Calculation of the VUT 2000 WH-4 water heater parameters
Water heater parameters calculation example:
Air Speed.
Starting from 2000 m
3
/h on the air flow scale draw a vertical line
till the air speed axis which makes 3.75 m/s.
Supply air temperature.
Prolong the line
up to the point where it crosses the outside air temperature (descending curve, e.g. -15°C) then draw a horizontal line
from this point to
the left till crossing water in/out temperature curve (e.g. 70/50). From this point draw a vertical line
to the supply air temperature axis on top of the graphic (31 °C).
Heating coil capacity.
Prolong the line up to the point where it crosses the outside air temperature (ascending curve, e.g. -15°C) and draw a horizontal line
from this point to the right
until it crosses water in/out temperature curve (e.g. 70/50), from here draw a vertical line
up to the scale representing the heating coil capacity (35 kW).
Water flow.
Prolong the line down to water flow axis at the bottom of the graphic
(0.43 l/s).
Water pressure drop.
Draw the line
from the point where line
crosses the black curve to the pressure drop axis. (9 kPa).
Air temperature at outlet from the heater [°C]
Air speed inside the heater [m/s]
Water flow through the water heating coils [l/s]
Wa
ter pressure drop [kP
a]
Air flow through the heater [m
3
/h]
Coil heating capacity [kW]
Ex
ternal air temperature [°C
]
VUT 2000 WH-4
