Passive Solar Systems for the Promotion of Thermal Comfort in African Countries: A Review (original) (raw)
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.
Towards Sustainable Rural Development in South Africa through Passive Solar Housing Design
Wind Solar Hybrid Renewable Energy System, 2019
Rural low-cost housing in South Africa is characterised by poor thermal performance, as these houses are designed with no consideration of utilising ambient weather conditions for indoor thermal comfort. Hence, a prototype low-cost energy efficiency house was built based on the principle of passive solar design to avert the energy burden faced by low-cost house dwellers. Passive solar design in this context is the strategic selecting and locating of building envelope components to utilise the ambient weather factor of a house to enhance indoor thermal comfort. The aim of this study is to analyse the thermal performance of the passive solar house. To this effect, the indoor and weather conditions of the house which include air temperature, relative humidity, and solar radiation were monitored. The thermal contribution of the windows was determined from the measured data. In summer, 49% of the whole building air temperature and approximately 85% of its corresponding relative humidity were found within the thermal comfort. Only 23% temperature and 78% relative humidity distributions of the whole building were in the thermal comfort zone in the winter season. The daily cumulative heat contribution of the clerestory windows with no shading material was higher than that of the south-facing windows by 1.08 kWh/m 2 /windows in summer and 4.45 kWh/m 2 /windows in winter.
1980
In the southeast, there exist many climate zones where heating needs are low to minimal. If designed properly, a passive solar heating system can provide most of a home’s heating needs for much of the heating season. Because the sun is the main source of heat, a passive solar home includes four features that distinguish it from a conventionally heated home: A method to collect solar energy; A way of storing that energy; A system to distribute heat to the living spaces; and A means for controlling the heat that reaches living spaces. A passive solar home should always be built to meet high energy conservation standards for the region in which it is built. Carefully planning and designing a home to balance the glass and thermal mass storage areas is crucial in the southeast. Otherwise, the house may overheat, underheat, or have undesirable temperature swings.
Momona Ethiopian Journal of Science, 2021
A substantial share of the total energy in various countries is consumed by industries and manufacturing sectors. Most of the energy is used for low and medium temperature process heating (up to 3000C) as well as low and medium cooling capacity (up to 350kW). To meet the demand, the industrial sector consumes most of its energy in either thermal (heat) or electrical energy forms. The use of fossil fuels accounts for about half of the overall share. This resulted in a necessity to commercialize local and clean renewable energy sources efficiently considering the reduction of economic dependence on fossil fuels and greenhouse gases emission. As such, solar energy has proven potential and resulted in considerable development and deployment of solar heating industrial processes (SHIP) and solar cooling systems in recent times. Thus, an attempt to present a review of the available literature on overall energy intensiveness, process temperature levels, solar technology match, and solar th...
Solar Water Heating Systems Potential in Nigeria-A Review
International Journal of Advances in Scientific Research and Engineering (ijasre), 2019
A review of solar water heating systems potential in Nigeria with their applications is presented. Thus, the paper presents an extensive study of the research carried out on the solar water heating system. In the present study, both experimental and theoretical developments in the field of solar water heater have been reviewed thoroughly. Extensive study has been conducted to further optimize the thermal efficiency of solar water heating. The paper provides a consolidated summary of the various types and components of solar water heating system that includes collector, storage tank and heat transfer fluid. Review of related past works done is included in this paper that shows different approaches from different researchers in order to improve the system efficiency. In addition to this, detailed findings and discussion on the limitations of existing research, research gap and recommended possible modifications is made.