The green block is constructed with a 25-m² facade facing south, which is set up as a large sun wall completely integrated in the building design. The facade is the backbone of the passive solar system, which aims to accumulate and partly use the solar energy during daylight hours, and to use the remainder at night or in times of less solar activity.

The facade is constructed as a uniform solar collection area, made up of a heavy concrete wall painted dull black on the outward surface in order to adsorb the radiation optimally. The concrete wall is slightly withdrawn compared to the building facade, which consists of glass, and in between there is room for airflow. Erected on the inside of the concrete wall, a light yet well-insulated wall hinders direct and uncontrolled heat transmission into the building. As on the outside, an inside gap is constructed between the two walls. The two air gaps are connected at the bottom of the concrete wall.

In daylight hours the wall will heat the air in the outer gap, and subsequently transfer the heated air to the central ventilation system. The airflow is controlled and regulated by the ventilation system in correspondence with the heating demand of the building.

Inside the building, the ventilation system is designed as a conventional system with exhaust air from the cooking canopy and the bathroom exhaust, and supply of fresh heated air in the living rooms.

The central ventilation unit is equipped with cross heat exchangers, which transfer up to 70% of the heat in the exhaust air to the incoming fresh air. In order ensure a temperature in the incoming airflow that conforms to the heating demand, the influx is transferred to the top of the inside air gap, where it is distributed horizontally so the air can descend slowly in the inside air gap. At the bottom the cool air is drawn into the bottom of the solar wall by the lower pressure. In the outer gap the air is heated and ascends to the top and back into the ventilation system.

In order to ensure that the air in the outer gap is not heated to an uncomfortably high level, the air ducts are provided with a temperature regulated by-pass mechanism, which leads a part of the airflow round the sun wall. In order to mitigate excessive cooling in winter with ensuing energy losses, the same function is triggered if the sun wall is colder than the outside air coming in.

If there is a heating demand beyond the capacity of the sun wall, the ventilation system can heat the incoming air through surfaces heated by the hot water supply. The heating surfaces are dimensioned to enable low-temperature heat transfer, which ensures high over-all energy efficiency, particularly when it comes to the energy contributions from the solar system in periods with moderate solar activity. Domestic hot water is supplied partly by a solar collection system, and partly by the local district heating grid. The entire system is monitored and controlled by a central energy management system (EMS).

General information on the technologies:
Ventilation and heat exchange
Passive solar energy
Solar water collectors
EMS


Suppliers of technology:

Solar collection:
ARCON Solvarme A/S Arcon produces and markets four different flat-plate collector models for use with domestic solar energy systems and one special model for large plants. Furthermore Arcon offers storage-tanks, control-units, etc. for implementation in complete ARCON solar energy systems.
Address: Jyttevej 18
DK-9520 Skørping
Phone: +45 98391477
Fax: +45 98392005
e-mail: export@arcon.dk
www.arcon.dk

Ventilation: H.J.
Ventilation Service A/S
H.J. Ventilation implements and maintains ventilation systems.
Address: Herluf Trolles Vej 34
DK-5220 Odense SØ
Phone: +45 66156115
Fax: +45 66158933
e-mail: hj-v@hj-ventilation.dk
www.hj-ventilation.dk

Energy monitoring: TAC AB
TAC Vista is a software solution for building automation, which controls, checks and analyses all building operations.
Address: Jägershillgatan 18
S-213 75 Malmö Sweden
Phone +46 (40)386850
Fax: +46 (40)218287
e-mail: info@tac.se
www.tac-global.com