Passive Solar Systems for the Promotion of Thermal Comfort in African Countries: A Review (original) (raw)
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Passive Solar Techniques to Improve Thermal Comfort and Reduce Energy Consumption of Domestic Use
World Academy of Science, Engineering and Technology, International Journal of Electrical, Computer, Energetic, Electronic and Communication Engineering, 2016
Passive design responds to improve indoor thermal comfort and minimize the energy consumption. The present research analyzed the how efficiently passive solar technologies generate heating and cooling and provide the system integration for domestic applications. In addition to this, the aim of this study is to increase the efficiency of solar systems system with integration some innovation and optimization. As a result, outputs of the project might start a new sector to provide environmentally friendly and cheap cooling for domestic use.
Overheating caused by passive solar elements in Tunis. Effectiveness of some ways to prevent it
Renewable Energy, 1993
Although Tunisian winters are mild compared with northern regions, there are heating requirements ; their limited level suggests that passive solar energy would probably be able to meet them. However, the summer is hot enough, and one may wonder whether a solar design oriented toward the cold season would not induce severe overheating. Numerous studies have dealt with the heating performance of passive solar elements, but very little has been done to analyze their behavior in hot climatic conditions. The National School for Engineers of Tunis has built a passive solar pavilion which has been carefully instrumented. Special care has been devoted to the summer behavior of the pavilion. In this paper we describe some of the actions taken to prevent overheating, and we investigate their efficacy both by analysis of recorded measurements and by simulation. It is found that night ventilation is the most responsible action in decreasing room temperature, and that Trombe wall screening is more efficient than operating the walls as a solar chimney ; overhangs are of valuable aid, and shuttering of the direct gain element also helps against overheating. The high thermal capacity results in a very stable room temperature, and plays an essential role for cooling when coupled with night ventilation. Finally, it is found that if appropriate action is taken in the hot season, a house equipped with passive solar heating elements can reach a very acceptable level of comfort in summer time.
Applied Thermal Engineering, 2019
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Solar Thermal Power Plants in West Africa: Site Selection and Potential Assessment
Proceedings of the ISES Solar World Congress 2011, 2011
In some countries like landlocked Burkina Faso, electricity production is dominated by diesel plants (68 % in Burkina Faso) whereas the totality of oil consumed in these countries are imported and carried either by train or by road from the coast. This heavily escalates electricity production cost and thereby making its expansion to poor rural and peri-urban areas a mirage. Moreover, environmental concerns are associated with conventional thermal power plants with the release of greenhouse gases and sulphur dioxide, source of acid rains. There is therefore the need to look for alternative sources to produce electricity in a sustainable manner in Africa. In that regard, Solar Thermal Power (STP) Plants appear to be good candidate; however, with the exception of Northern and Southern Africa where extensive work is being conducted, potential assessment of Solar Thermal Power Plant in West Africa is yet to be done. This paper presents results of an ongoing research which aims at assessing the potential of STP for electricity generation in West Africa. The study considered only 1 % of the suitable land area with daily DNI greater or equal to 5 kWh/m 2 .day, a land slope less or equal to 3 % and distance to transmission line not more than 100 km and showed that West Africa has a potential nominal capacity of 20.16 GW for Parabolic trough technology.
A passive solar system for thermal comfort conditioning of buildings in composite climates
Solar Energy, 2001
Passive solar heating is a well established concept in cold climates, but passive systems which provide heating, cooling and ventilation depending on the season are less common. Some of the known systems in this category are: Sky-Therm, earth-air tunnel, the Silvestrini Bell, and the Barra-Costantini System, which are applicable in composite climates. Large areas of Central and Northern India have a composite climate, which includes hot-dry, hot-humid and cold climatic conditions. The present paper describes the development of a solar passive system, which can provide thermal comfort throughout the year in composite climates. In the first phase, passive model 1 comprising two sets of solar chimneys was developed and monitored for its performance for 1 complete calendar year. Based on the feedback and experience, an improved version of model 2 was developed. In model 2 both the trombe wall and sack cloth cooling concepts were incorporated, in order to make it more effective and also to give it a more compact and aesthetic appearance. Detailed system descriptions along with year-round performance data are given in this paper.
This paper deals with the energetic performances of a Solar Heating Prototype (SHP) conceived in our laboratory to prevail the Tunisian households' air-heating needs. The conceived SHP mainly consists of a flat-plate solar collector, solar hot water tank and an active layer integrated inside a single room. Firstly, a complete model is formulated taking into account various modes of heat transfer in the SHP by means of the TRNSYS simulation program. To validate the TRNSYS model, experimental tests under local weather conditions were performed for 2 days spread over 2 months (March and April 2013). Predicted results were compared to the measurements in order to determine the accuracy of the simulation program. A parametric study was then achieved by means of the TRNSYS program in order to optimize SHP design parameters (Collector area, collector mass flow rate, floor mass flow rate, storage tank volume and thickness of the active layer). The optimization of all design parameters shows that to achieve a maximum performances from the SHP it is essential to use a solar collector with an area equal to 6 m 2 area, a collector mass flow rate equal to 100 kg h À1 and a hot water storage tank with a capacity equal to 450 l. Concerning the floor heating, the optimal values of mass flow rate and the active layer thickness are 200 kg h À1 and 0.06 m, respectively. The long-term SHP performances were afterward evaluated by means of the Typical Meteorological Year (TMY) data relative to Tunis, Tunisia. Results showed that for an annual total solar insolation of about 6493.37 MJ m À2 the average solar fraction obtained is about 84%. The results show also that the request of auxiliary energy is limited to the cold months of the year chiefly from December to Mars. The results show also that the SHP reduce the relative humidity inside the monozone room of about 40%.
A Passive Solar Air-House Conditioning System Integrated in Tunisian households
Journal of Solar Energy Research Updates, 2021
In Tunisia, the buildings' space heating sector represents a major part of the total energy consumption budget. These issues have been increasingly prominent concerns since the energy crisis. Hence, interests have been growing to adopt renewable energies as viable sources of energy that offer a wide range of exceptional benefits with an important degree of promise, especially in the buildings sector. However, the management of renewable energy sources for space air heating/cooling is usually not economically feasible compared with the traditional carriers. In this chapter, we present a passive energy system, called airconditioning cupboard which exploits renewable energies (hot water supplied from solar collector [40-50°C] and cold groundwater (19°C)) as thermal sources, is conceived and tested in our laboratory (Laboratory of Thermal Procedure, LPT Tunisia). To evaluate the airconditioning cupboard efficiency indoor experiments were carried out under varied Tunisian environmental conditions for several days. Results show that the airheating system has good thermal effectiveness (80 %). It permits to the maintenance of the temperature inside the experimented room at the range of [24-27°C] during the cold months and [20-23°C] during hot months. A theoretical model is employed for the sizing of the airconditioning cupboard to obtain the required temperature values. This model allows also the determination of the air-cupboard conditioning thermal performances.
Heating performance of an experimental passive solar house in Tunisia
Renewable Energy, 1993
In Tunisia, heating requirements in winter are not very high; solar radiation is abundant and offers a high potential of energy for heating. Passive conversion seems suitable due to the low associated extra costs. Moreover, the high thermal capacity required for solar buildings is usually present in single family houses. The National School for Engineers of Tunis has built a solar passive pavilion which has been carefully instrumented. We present, in this paper, an analysis of the recorded measurements. One important question to investigate is whether, in our climate, passive solar energy can totally fulfil the heating requirements. Another interesting aspect is the simultaneous presence of Trombe wall and direct gain elements, which are complementary in many respects. It is found that direct gain element shows a higher efficiency, but Trombe wall supplies energy gains, which are very appreciable at evening. Thermal circulation in its air gap has shown to be useless in our climate. The combined effect of the two elements results in autonomy in heating requirements. Experimental testing has been completed by computer simulations, which have indicated that thermal insulation is decisive for the average room temperature, but thermal capacity results in high temperature stability. Simulations have also shown that the constructed Trombe wall is too thick, and that double glazing is more efficient than night insulation to protect this element ; whereas for the direct gain element, double glazing is hardly justified in our climate. Experimental and simulation results demonstrate that in Tunisian conditions, proper design of passive components can guarantee heating autonomy at low cost.