Compared to single-layer wall with openable windows, a double-layer facade enables a different air circulation indoors. An additional layer of glass, which covers the windows, blocks the natural flow of air and reduces the exchange of air between indoors and outdoors. The difference between the air flow through windows situated from the side of prevailing winds and air flow through the window least exposed to the wind is lesser than in the case of traditional window. This circulation is also less affected by the extent of this window’s opening [K. Daniels].

[5] The collector was modeled after the CPC Star azzurro from Ritter GmbH & Co. KG with the following coefficients: po= 0.675, k1=0.697, k2=0.003.

[6] Introduction

The Italian Ministry for the Environment and Ministry of Justice signed a Memorandum of Understanding on November 7th, 2001 for the promotion of solar heating in Italian Jails. The main purpose of the agreement was the installation of up to 5,000 m2 (3.5 MWth) of solar thermal collectors.

Goals of the “Solar Jails” program are to reduce the energy consumption in jails, as buildings owned by public authorities with high and constant annual DHW demand, and to encourage the use of solar heat at large scale. However, besides the environmental and technical aspects addressed, the most challenging purpose of the initiative is the empowerment of the prisoners trained to install and to maintain the plant. In particular, the professional qualification gained on solar are expected afterwards to increase the reemployment opportunities.

[8] Until this moment only two sets of parameters are included in the standard. A set originally from f-chart method [6] applicable to solar pre-heat/solar only systems for hot water preparation and a set for a space heating system of type “direct floor heating” [3]

[9] Presently this area is no longer mandatory but the designer has to prove that, using a “better” collector then a defined reference collector the same Esolar is obtained with a lower collector area then the one obtained with the rule of 1m2/conventional occupant.

[10] Buildings studied

Two typical XVIII century residential buildings of the downtown area of Porto were chosen to be analysed in detail (figure 1). These buildings were undergoing a retrofitting process, already designed after the RCCTE became effective. The study concentrated in the analysis of the retrofitting design and on its compatibility with the regulation and with the conditionings of being at an historical area.

The magnitude of the retrofittings is such that it surpasses 25% of its value, so they must comply with the regulation for new buildings. On the other hand, the regulation foresees that it may not be fully applied in buildings in historical areas if incompatibilities (with the patrimonial values) are found and duly justified. 4 apartments were selected for detailed analysis in building 1, and 2 apartments in building 1.

[11] Suggested surface orientations refer to the northern hemisphere. For southern latitudes readapt the orientation accordingly.

[12] Intervention area and weather

The project is developed at the border of the Chubut plateau, near the pre­cordillera (Figure 4). The weather is the Patagonia Arid Weather Type, characterized by constant winds, low winter temperatures and snows, and strong and periodic aridity conditions.

Figure 4: Geographic situation.