Civil Engineering Reference
In-Depth Information
Table 1 Main features and climatic data of the LH
Climatic data
Building features
Minimum and maximum temperature (C)
-5; 37
Number of levels
3
Heated floor area (m
2
)
Mean annual humidity (%)
0.67
481.76
Mean annual horizontal solar radiation (W/m
2
)
Volume (m
3
)
302
1,475.33
Latitude
4328' N
Heated floor area to
volume
0.33
Longitude
1304' E
S/V ratio
0.73
Altitude (m)
130
Table 2 U-values for the envelope elements
External structures
U-value [W/(m
2
K)]
U-value [W/(m
2
K)]
Windows
Walls
0.15
Global
1.4
Floor
0.30
Glass only
1.15
Roof
0.25
Table
2
presents the thermal properties and the material composition on the
building envelope.
The required thermal energy is supplied with an equipment, made of a solar
collectors system, three geothermal probes, a heat pump, an air handling unit
(AHU), an auxiliary boiler, a photovoltaic system (Fig.
2
). The geothermal heat
pump exchanges with the ground through vertical probes, the solar thermal col-
lectors and the auxiliary boiler, which operates in case of failure of the other
systems.
Each flat is heated by means of a radiant floor supplied by the GHP. During the
summer season, excluding the hottest days, the cooling system uses the natural
cooling provided by a ground-coupled heat exchanger.
In winter, the solar system is integrated by the heat pump in heating mode in
order to reach around 40 C in the upper part of the storage tank, thus allowing the
production of domestic hot water (DHW) and of water for feeding the radiant
floors from the middle area of the tank. DHW is heated and then collected in a
smaller secondary tank, connected to an auxiliary gas burner that is employed
when the system needs a thermal integration according to a fixed set point
temperature.
During the summer season, the solar system fulfills the DHW requirement and
the GHP is used in cooling mode to produce cold water at 15-18 C through the
use of mixing valves, to feed the radiating floors.
A proper mechanical ventilation system is installed with heat recovery and
preconditioning in an underground air duct. The AHU supplies neutral air in rooms
and there is a heat recovery system before the expulsion of exhausted air. The
outer air is naturally preconditioned (heated in winter and cooled in summer)
through a 10-m-long underground duct placed before entering the air into the
AHU.
