Daikin ERLA16DAV3 - Selecting the Volume and Desired Temperature for the DHW Tank

6 | Application guidelines
Installer reference guide
52
ERLA11~16DAV3+W1 + EBVH16SU23DJ
Daikin Altherma 3 R F
4P655196-1 – 2021.09
6.4.2 Selecting the volume and desired temperature for the DHW tank
People experience water as hot when its temperature is 40°C. Therefore, the DHW
consumption is always expressed as equivalent hot water volume at 40°C.
However, you can set the DHW tank temperature at a higher temperature
(example: 53°C), which is then mixed with cold water (example: 15°C).
Selecting the desired temperature for the DHW tank consists of:
1 Determining the DHW consumption (equivalent hot water volume at 40°C).
2 Determining the desired temperature for the DHW tank.
Determining the DHW consumption
Answer the following questions and calculate the DHW consumption (equivalent
hot water volume at 40°C) using typical water volumes:
Question Typical water volume
How many showers are needed per
day?
1shower = 10min×10l/min = 100l
How many baths are needed per day? 1bath = 150l
How much water is needed at the
kitchen sink per day?
1sink = 2min×5l/min = 10l
Are there any other domestic hot water
needs?
—
Example: If the DHW consumption of a family (4 persons) per day is as follows:
▪ 3 showers
▪ 1 bath
▪ 3 sink volumes
Then the DHW consumption = (3×100l)+(1×150l)+(3×10l)=480l
Determining the desired temperature for the DHW tank
Formula Example
V
1
=V
2
+V
2
×(T
2
−40)/(40−T
1
) If:
▪ V
2
=230l
▪ T
2
=54°C
▪ T
1
=15°C
Then V
1
=359l
V
1
DHW consumption (equivalent hot water volume at 40°C)
V
2
Required DHW tank volume if only heated once
T
2
DHW tank temperature
T
1
Cold water temperature
DHW tank volume
Integrated DHW tank volume: 230l (=V
2
)
Energy saving tips
▪ If the DHW consumption differs from day to day, you can program a weekly
schedule with different desired DHW tank temperatures for each day.
▪ The lower the desired DHW tank temperature, the more cost effective. By
selecting a larger DHW tank, you can lower the desired DHW tank temperature.