Energetic performances of an optimized passive Solar Heating Prototype used for Tunisian buildings air-heating application (original) (raw)
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A novel experimental investigation of a solar cooling system in Madrid
International Journal of Refrigeration-revue Internationale Du Froid, 2005
This paper reports novel experimental results derived through field testing of a part load solar energized cooling system for typical Spanish houses in Madrid during the summer period of 2003. Solar hot water was delivered by means of a 49.9 m2 array of flat-plate collectors to drive a single-effect (LiBr/H2O) absorption chiller of 35 kW nominal cooling capacity. Thermal energy was stored in a 2 m3 stratified hot water storage tank during hours of bright sunshine. Chilled water produced at the evaporator was supplied to a row of fan coil units and the heat of condensation and absorption was rejected by means of a forced draft cooling tower. Instantaneous, daily and period energy flows and energy balance in the installation is presented. System and absorption machine temperature profiles are given for a clear, hot and dry day's operation. Daily and period system efficiencies are given. Peak insolation of 969 W m−2 (at 12:30 solar time on 08/08/03) produced 5.13 kW of cooling at a solar to cooling conversion efficiency of 11%. Maximum cooling capacity was 7.5 kW. Cooling was provided for 8.67 h and the chiller required a threshold insolation of 711 W m−2 for start-up and 373 W m−2 for shut-down. A minimum hot water inlet temperature to the generator of 65 °C was required to commence cold generation, whereas at 81 °C, 6.4 kW of cooling (18.3% of nominal capacity) was produced. The absorption refrigeration machine operated within the generation and absorption temperature ranges of 57–67 and 32–36 °C, respectively. The measured maximum instantaneous, daily average and period average COP were 0.60 (at maximum capacity), 0.42 and 0.34, respectively. Energy flows in the system are represented on a novel area diagram. The results clearly demonstrate that the technology works best in dry and hot climatic conditions where large daily variations in relative humidity and dry bulb temperature prevail. This case study provides benchmark data for the assessment of other similar prototypes and for the validation of mathematical models.
Parametric optimization using dynamic simulation of a solar thermal system for producing hot water, space heating and cooling was developed. The system layouts include a single-effect absorption chiller activated by heat generated by flat plate solar collectors and stored in a solar storage tank. Two construction types were compared; the first is the typical construction in Algeria (low thermal mass with U-values of 1.25 W/m 2 K, single glazing), which represents the majority in the country, while the second is a High-Energy-Performance building (with U-values of 0.35 W/m 2 K, double glazing), representing the pilot project called ECO-BAT. Three of Algeria's regions were considered to evaluate the climatic effect of solar systems integration. Algiers represents the coastal region; Djelfa, the highlands region; Tam-anrasset, the Sahara region. In parametric study, two solar collectors' field parameters were analysed, including the surface area and the tilt angle. The results indicated that building loads are significantly reduced (12%, 44% and 22% for Algiers, Djelfa and Tamanrasset, respectively). The solar energy contribution is more than 60% for all cases, a significant contribution for an efficient building. In all cases, we observed that the solar fraction reaches more than 45% when the optimum parameters of the solar system are selected.
Energy, 2016
Parametric optimization using dynamic simulation of a solar thermal system for producing hot water, space heating and cooling was developed. The system layouts include a single-effect absorption chiller activated by heat generated by flat plate solar collectors and stored in a solar storage tank. Two construction types were compared; the first is the typical construction in Algeria (low thermal mass with Uvalues of 1.25 W/m 2 K, single glazing), which represents the majority in the country, while the second is a High-Energy-Performance building (with U-values of 0.35 W/m 2 K, double glazing), representing the pilot project called ECO-BAT. Three of Algeria's regions were considered to evaluate the climatic effect of solar systems integration. Algiers represents the coastal region; Djelfa, the highlands region; Tamanrasset, the Sahara region. In parametric study, two solar collectors' field parameters were analysed, including the surface area and the tilt angle. The results indicated that building loads are significantly reduced (12%, 44% and 22% for Algiers, Djelfa and Tamanrasset, respectively). The solar energy contribution is more than 60% for all cases, a significant contribution for an efficient building. In all cases, we observed that the solar fraction reaches more than 45% when the optimum parameters of the solar system are selected.
International Journal of Thermodynamics, 2015
Solar or solar assisted heating and cooling systems are becoming widespread to reduce CO2 emissions. Efficient radiant space heating and cooling systems can be used to decrease the energy bills and improve occupant thermal comfort in buildings. This study uses the TRNSYS program, for the modeling and simulation of solar assisted radiant heating and cooling of a building with the domestic hot water supply, to examine the effects of various parameters on energy consumption. Calculations are performed for a typical meteorological year (TMY) and ten attached houses in Istanbul, Turkey with hot water and chilled water storages on a six minute time step basis. Graphs showing variations of the room temperature and room relative humidity indicate satisfactory thermal comfort. Daily average COP of the absorption cooling system is improved by suitable choice of the type and size of the collectors. Sizes of the hot water and chilled water tanks are also important parameters; their roles are shown by their effect on the discarded portion of the heat from the collectors and the energy amount supplied by the auxiliary heater. It is concluded that the presented model for a solar assisted radiant heating and cooling of ten attached houses, with the domestic hot water supply, natural gas fueled auxiliary heater, hot water and chilled water storage tanks have considerable advantages; these should be maximized by optimizing the sizes of the solar collectors and storage tanks using a simulation program.
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.
Efficiency of a Solar Hydronic Space Heating System under the Algerian Climate
Engineering, Technology & Applied Science Research, 2016
Hydronic heating systems supplied by renewable energy sources are one of the main solutions for substituting fossil fuel and natural gas consumption. This paper presents the development of modeling and analysis of a solar hydronic heating system in an existing single-family house built in 1990’s heated by low-temperature radiators. The simulation has been used to study the potential of using this system under climatic conditions in Algeria. And for this purpose, a component based on the simulation model for the thermal behavior of each component of the system are carried out in order to evaluate the economic performance for this system. The system is compared, with a conventional high-temperature boiler system. The results indicated that single-family houses could be heated with solar hydronic heating and provided an acceptable level of thermal comfort in the room with 22°C, according to the results of the analysis, the solar energy covers only 20.8% of the total energy consumption ...
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.
2023
The aim of this work is to investigate the energetic performance of a solar cooling system using absorption technology under Moroccan climate. The solar fraction and the coefficient of performance of the solar cooling system were evaluated for various climatic conditions. It is found that the system operating in Errachidia shows the best average annual solar fraction (of 30%) and COP (of 0.33) owing to the high solar capabilities of this region. Solar fraction values in other regions varied between 19% and 23%. Moreover, the coefficient of performance values shows in the same regions a significant variation from 0.12 to 0.33 all over the year. A detailed parametric study was as well carried out to evidence the effect of the operating and design parameters on the solar air conditioner performance.
Energy Procedia, 2015
In the present article, we present a numerical simulation (winter and summer) of a low energy housing of 70 m² surface area in Algiers region. This region is part of the climate zone, A which is characterized by a cool winter and hot and humid summer. In our simulation, we use the Pleiades and Comfie software. In Order to see the temperature variation of the comfort zone; we illustrate our simulations for two weeks, the hottest and coldest week of the year. To know the energy needs (heating and cooling) we run a simulation with the thermostat instructions (the comfort temperature must be between 20 ° C and 24 ° C).we take into account different scenarios: the occupancy, the ventilation, the occupation and the dissipated energy. Note that the external temperatures injected are measured values. We integrate also in the study a solar water heating system, the simulation is done with solo software developed by Tecsol. The results shows clearly that the comfort is attended in summer, but not quite in winter and the good efficiency of water heating installation.
Energies
This study was carried out to optimize a computational model of a new underground passive solar greenhouse to improve thermal performance, storage, and saving of heat solar energy. Optimized and conventional passive solar greenhouse were compared in regards of indoor air temperature, irradiation, and energy demand. Six different materials were used in the conventional model. In addition, TRNSYS software was employed to determine heat demand and irradiation in the greenhouse. The results showed that the annual total heating requirement in the optimized model was 30% lower than a conventional passive solar system. In addition, the resulting average air temperature in the optimized model ranged from −4 to 33.1 °C in the four days of cloud, snow, and sun. The average air temperature in the conventional passive solar greenhouse ranged from −8.4 to 24.7 °C. The maximum monthly heating requirement was 796 MJ/m2 for the Wtype87 model (100-mm lightweight concrete block) and the minimum value...