10.07.2015   Sonar-Collecttors

Thickness K K cm w/mq K w/mq K External structural walls external plaster 1,5 Poroton Aktuell with insulation plaster 49 0,22 internal plaster 1,5 e x t Roof tiles 1 e air chamber 5 r waterproof layer 0,5 0,26 n Extrude polystirene insulation 12 a precompressed wood slab 1,5 i Pavement ventilated air chamber 50 solaio pignate e travetti precompressi 15 massetto 5 0,46 f Extrude polystirene insulation 5 a radiant pavement 10 c ceramic 1 e s Windows abete wood frame 6 1,67 low-e glass in layer 2 (solar gain) 0,4 argon gas chamber 1,2 1,1 1,5 glass 0,4 Tab. 1 — Characteristics of the external surfaces . The space heating energy demand

The house has been simulated with the DEROB LTH (Dynamic Energy Response Of Buildings) version 00.04, developed by the Swedish Department of Building Science belonging to the Lund Institute of Technology. Natural ventilation has been considered

2609 kWh/y for heating (29 kWh/m2y)

Fig. 8 — Model developed by DEROB LTH simulation programme

during the whole year.

The results indicate that the volume A will re and 2812 kWh/y for cooling (30 kWh/m2y). This is a lower demand compared to the heating demand of a typical Italian residential building.

4.2 The heating systems (solar and biomass)

Since the energy consumption for heating is low, a great part of it could be covered by a solar heating system. Therefore two solar heating systems have been designed: a water solar system with solar collectors to cover a great part of the heating demand and the DHW needs (Costruzioni Solari s. r.l.[16]) and an air solar system (Solarwall[17]) to preheat the inlet air during the winter sunny days. The

Fig. 9 — Conventional solar system winter behaviour

solar system will heat the house through a radiant pavement system at low temperature. The whole solar system is integrated with a wood stove to cover the complete heating demand during the coldest period.

The water solar system

Fig. 10- Solar water system for space and domestic water heating scheme

Six solar thermal collectors of 1,9 sq meters each and one boiler of 700 litres for the space heating system are located in the south wall as reported in figure 9. The solar system scheme is reported in figure 10. This system should cover from 64% to 100% of the heating demand. In order to increase this percentage, a solar air system has been designed.

Days/ month

Month

Days /month

Average daily radiation in the sloped surface

Average

system

efficiency

(Qa) Daily

average

thermal

energy

available/ sq

m

(Qa) Monthly thermal energy available/ sq m

Monthly

thermal

energy

available

(Ea) monthly

energy

demand

Surplus/integ

ration

% solar fraction

kWh/m2 day

kWh / m2 day

kWh / m2 month

kWh/

month

kWh/

month

kWh/

month

%

31

January

31

3,14

0,40

1,26

39

443

600

— 157

74%

28

February

28

3,42

0,40

1,37

38

437

542

— 105

81%

31

March

31

3,81

0,45

1,72

53

606

600

6

101%

30

April

0

0

0,50

0

0

0

31

May

0

0

0,50

0

0

0

30

June

0

0

0,50

0

0

0

31

July

0

0

0,50

0

0

0

31

August

0

0

0,50

0

0

0

30

September

0

0

0,50

0

0

0

31

October

0

0

0,50

0

0

0

30

November

30

3,04

0,45

1,37

41

467

581

— 113

80%

31

December

31

2,73

0,40

1,09

34

385

600

— 215

64%

365

TOTAL

151

3,23

0,47

1,36

205

2.338

2.923

80%

Table 2 — Heat production and the coverage (in %) of the solar system.