Summer thermal behaviour

Подпись: Solar Time (hs) ♦ Meetings Room о Doctor's Offices 4 and 5 д Doctor's Offices 1 to 3 —n—North Corridor —Ж— Outdoor Подпись: Solar Time (hs) • Access д South corridor —о— Laboratory —ж— Outdoor

A similar analysis was performed for both building sectors in a typical summer day. In the simulations, the openings added in the Health sector were considered closed, and the air chamber added in the Development sector was ventilated to avoid overheating. The thermal behaviour of the Health sector in summer (Figure 8) shows that, during the sunshine hours, the indoor air temperatures are around 30 °С with an average outdoor temperature of 22.9 °С. Only during the night the building enters inside the comfort zone. In the Development sector the mean air temperature is around 26 °С (Figure 9) with a mean outdoor temperature of 22.9°C..

Подпись: (b)(a)

Fig. 8. Summer hourly temperature in the Health Sector: (a) North thermal zones, and (b) South thermal

zones.

In this sector, the indoor temperature, even without internal gains, is always greater than the outdoor temperature. In the afternoon, the west windows cause glare and dazzling, because the sunlight incides on the corridor floor from 14PM to 16PM and on the internal wall connecting the corridor with classrooms and services since 14PM to sundown

In both sectors of the building, natural ventilation and ceiling fans are suggested. Aeolian extractors in the ceilings are suggested to remove the warm air. In the Health sector, the crossed ventilation cannot be practiced because of the location of the offices in the center of the building. In summer, when the sun exposition of walls should be minimized, the East and West envelopes of the Development sector are highly exposed. In addition, solar radiation from West will cause overheating and glare in the afternoon, so shading devices are imperative for glazed areas.

4. Conclusions

The improvements to the original design of the CIC building showed to be effective to reduce the heating and cooling loads and to obtain important energy-saving. The strategies to be applied were selected after a careful analysis of the thermal behaviour of the original design, that evidenced an uncomfortable indoor conditions in the Development Sector both in winter and summer: in winter, when high levels of solar collection are needed, this Sector only collects direct solar radiation from East and partially from West, due to the shading of neighbouring buildings; in summer, when direct solar radiation must be avoided, the Sector is unshaded and collecting both from East and West. Furthermore, in the afternoon, the west windows cause glare and increase overheating. The winter thermal behaviour of the Health Sector is better due to the high solar collection in North surfaces.

Some strategies were tested to improve the thermal behaviour of the building. Thus, to heat the offices of the Health sector in winter, the use of openings (1% of the wall area) connecting the North corridor and the offices was added, in order to introduce the hot air into the offices by natural convection. The openings must be closed during the night to prevent inverse air flow. In the Development sector, the addition of a tight air chamber in the roof (with ventilation in summer) was recommended.

In both sectors of the building, natural ventilation and ceiling fans are suggested for the summer period. The installation of aeolian extractors in the ceilings is proposed in order to remove the

warm air. The extractors can remove the warm air during the night. In the Health sector, the crossed ventilation cannot be practiced because of the location of the offices in the center of the building. In summer, when the sun exposition of walls should be minimized, the East and West envelopes of the Development sector are highly exposed. In addition, solar radiation from West will cause overheating and glare in the afternoon, so shading devices are imperative for windows and glazed areas.

It is expected that this project will serve as a demonstrative project, in order to to spread the application of passive strategies and solar equipment in public buildings of social use, and to minimize the impacts on the climate and the environment caused by the consumption of conventional energy. Also the training of professionals and design technicians of the Social Development Ministry, and the training of the people belonging to the cooperative work societies of Villa Zagala CICs in subjects like management, operation and control of CICs buildings is expected.

Aknowledgements

This project was partially supported by PAE (ex PAV) 22559, CIUNSa 1699, PICTO UNSa 36646, and the special project “Mejoramiento de la Envolvente y Equipamiento Solar con Fines Demostrativos y de Capacitacion para un Centro Integrador Comunitario (CIC) del Ministerio de Desarrollo Social en Villa Zagala — Partido de Gral. San Martin, Provincia de Buenos Aires”. SECYT.

References

[1] Righini R., Grossi Gallegos H., Raichijk C., (2004). Trazado de nuevas cartas de irradiacion solar global para Argentina a partir de horas de brillo solar (heliofania). Energias Renovables y Medio Ambiente, 14, 23-32.

[2] Hernandez A., (2003), Geosol: Una Herramienta Computacional Para el Calculo de Coordenadas Solares y la Estimacion de Irradiacion Solar Horaria, Avances en Energias Renovables y Medio Ambiente 7, 19 — 24.

[3] Flores Larsen S., Lesino G. A new code for the hour-by-hour thermal behaviour simulation of buildings. In: Proceedings of VII International Building Simulation Congress 2001, Rio de Janeiro, Brazil, 75-82.

[4] Flores Larsen S., Lesino G. Programa de diseno y simulacion de edificios. In: Proceedings of XI

Congresso Iberico e VIIbero-Americano de Energia Solar, Vilamoura, Portugal, 2002.

[5] LuzSol 1.1. http://www. labeee. ufsc. br/software/luzDoSol. html. Last accessed: July 29, 2008.

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