10.07.2015   Sonar-Collecttors

Domestic hot water (DHW)

The water stored in the facade is warmed by solar energy and it is delivered to the do­mestic hot water network according to the consumer demand. When there is consumption, water enters to the accumulator in facade from the city network at a constant inlet tempera­ture considered equal to 15°C.

Top temperature at tank is considered to be the delivery temperature to the load. No heat losses through the pipes are considered. The demand temperature is assumed constant and equal to 43°C.

Two consumption profiles will be considered, profile 1 presents water use at noon, whereas profile 2 does not. They are described in Table 1 and Table 2.

Time

Use

Flow rate

Total [I]

From:

To:

[l/min]

[kg/s]

8:00

8:15

Shower

5

0.083

72

8:15

8:30

Face and hands washing

1.9

0.03

27.36

13:30

13:45

Food preparation

2.0

0.0331

28.80

15:00

15:15

Fland dishwashing

1.04

0.0182

14.976

19:00

19:15

Clothes washing

4.48

0.074

64.504

20:00

20:15

Face and washing hands

1.9

0.03

27.36

Total:

235

Table 1: Water consumption profile 1-With noon draw

Table 2: Water consumption profile 2 — Without noon draw

Time

Use

Flow rate

Total [I]

From:

To:

[l/min]

[kg/s]

8:00

8:15

Shower

5

0.083

72

8:15

8:30

Face and hands washing

1.9

0.03

27.36

19:00

19:30

Food + hand dishwashing

3.75

0.062

108

19:30

19:45

Face and washing hands

1.9

0.03

27.36

Total:

235

If outlet temperature from tank is called OTL and inlet temperature ITL, useful energy from facade to satisfy domestic hot water load, is calculated as:

TOC o "1-5" h z QLOAD = mcp(OTL — ITL) (3)

Domestic hot water load will be:

Load = mcp(T demand — IT L) (4)

Then, auxiliary energy necessary to complement energy delivered by the facade will be:

Qaux = mcp(Tdemand — OTL) (5)