Glazing Cover Research Articles

Techno-environmental assessment of outdoor glazing cover of a building with multi-passive solar systems

With the expansion of urban areas and the growth of welfare levels, the energy consumption of buildings will increase in the next decades. Passive solar systems are one of the technologies to reduce energy consumption. In this paper, a building-integrated passive solar energy technology was studied in six different Scenarios including photovoltaic (PV) and Building Integrated Photovoltaic (BIPV) glazing windows, PV glazing façades, PV glazing double-skin façade, and simple double-skin façade. They were compared to the base model, respectively. It has been determined each scenario may be superior in one or more cases compared to other scenarios. Results show in the BIPV model, the inside temperature of the building was decreased by up to 1.3 degrees. The annual energy consumption for heating in the double-skin Scenario was reduced by about 17% compared to the base Scenario. The annual energy consumption for cooling in the building with PV glazing façade compared to the base scenario has decreased by more than 21%. Annually, CO2 emissions by 140%, and the cost of energy have decreased by 3493.4$ in building with PV glazing double skin facade and building with PV glazing facade, respectively. Finally, the shadow effect of the energy of the building is examined.

The Effect of Installing Temperature Stratifiers in PV/T Systems on Their Power Generation Efficiency Increases under Different Climatic Conditions

With the advent of the energy crisis, more comprehensive approaches to solar energy use are gaining traction, such as the Photovoltaic/Thermal (PV/T) system. The goal of this research is to determine the power efficiency increase of the PV/T system brought about by the temperature stratifier installed in the thermal tank. This PV/T system consists of two parts: a plate PV cell with a glazing cover and a water-cooling system with a thermal tank. In this paper, an optimization method for cooling systems is presented. A temperature stratifier is installed in a thermal tank to create a temperature stratification in it. The water in the lower layer becomes colder, which leads to a better cooling effect of the cooling system and increases the power generation efficiency of the photovoltaic cell (PV cell). The optimization of the above system is verified by mathematical modeling, and it is found that this method can indeed optimize the power generation efficiency of the PV/T system. The efficiency increase can reach more than 3%, and a comparison of the results for different climatic conditions leads to the conclusion that PV/T systems installed with temperature stratifiers will gain relatively more in cities with higher average ambient temperature and solar irradiation, while the effect of wind speed on this increase is limited in non-extreme cases.

Indirect solar dryer with a single compartment for food drying. Application to the drying of the pear

This work presents the experimental results relating to agri-food drying in an indirect solar dryer with a single compartment. This compartment has four facades. Which consist of: glazed cover above and aluminium walls at the bottom and an air layer bounded by them. The drying chamber is under the aluminium walls. The layers of glass, air and walls subjected to the solar flux act as an absorber and play an important role to enhance the heat transfer in the drying chamber.The designed dryer is a single compartment with a south-oriented roof. Moreover, this roof has two inclined surfaces with optimal angles of 50° and 34° from the horizontal plane to absorb the maximum solar irradiation during the year. This dryer is made up in the solar energy and environmental laboratory of the Faculty of Sciences of Rabat city (longitude: 6°49′57″, latitude: 34°00′47″).After this choice, the study presents the thermal and economic performances of the designed dryer. Firstly, in terms of thermal performance, the experimental tests show that the relative humidity inside the dryer can decrease by up to 10% compared to an external relative humidity between 70 and 90%, and the average temperature inside the dryer was 50 °C, in comparison to the average ambient temperature is 25 °C. These thermal performances allowed the pear to dry just after 24 h. Secondly, in terms of economic cost, this new design of the solar dryer is less expensive than conventional two-compartment solar dryers and encourages its use by the local producer.

The effect of thermo-fluid properties of air on the solar collector system

The changing behaviour of the flat plate collector upon varying the carrier fluid (air) properties was investigated with the help of energy and momentum conservation. The finite element analysis of a collector was carried out using pdex3 type equations. The white box modelling approach was considered to determine the velocity and temperature fields across the collector system. It was postulated that the temperature gradient for the carrier fluid at the viscous sublayer was negligibly small. The thermophysical properties, density and heat transfer coefficient, of the carrier fluid, are varied and their effect on the temperature and velocity fields was qualitatively examined. With the help of the proposed scheme, the solar collector efficiency was found to vary from 38.57 to 77.45%. The velocity of the fluid layer onto the surface of the collector plate increased from 1.12 to 1.43 m·s−1 as the heat transfer coefficient decreased from 30 to 19.73 W·m−2·K−1; however, it had a reverse effect for the fluid layer flowing past the glazing cover. The velocity of the carrier fluid increased from 0.0097 to 0.0852 m·s−1 at the boundary of the glazing cover, whereas it decreased by 22% at the vicinity of the copper plate. The numerical solution of energy equation slightly overestimated temperature of carrier fluid by 2.1%.

Numerical evaluation of the thermal performance of different types of double glazing flat-plate solar air collectors

As the main source of heat loss of flat-plate solar air collectors (FPSACs), single glazing cover reduces the thermal performance of FPSAC. This situation becomes serious when the ambient temperature is low or the inlet temperature is high. A double glass cover with good thermal insulation is a good solution. This work aims to investigate the thermal performance of double glazing FPSAC at low ambient temperature and high inlet temperature. The thermal performance of four FPSACs with single glazing (Model 1), double glazing filled with air (Model 2), double glazing filled with argon (Model 3), and vacuum glazing (Model 4) as the glass cover at different ambient temperatures, different heat transfer air (HTA) inlet temperatures, and different HTA volume flow rates are studied and compared. Result demonstrates that Models 2, 3, and 4 have better thermal performance at low ambient temperature and high inlet temperature compared with Model 1. When the inlet temperature is 65 °C and ambient temperature is −10 °C, the thermal efficiencies of Models 2, 3, and 4 are 1.65, 1.72, and 2.29 times higher than that of Model 1, respectively. The efficiency factor and total heat loss coefficient of Model 4 are 0.62707 and 2.21745, respectively.

Experimental investigation of a double glazing integrated solar water heater with corrugated absorber surface

The design of an integrated solar water heating system uses a single glazed cover does not keep the water heat at suitable temperature due to the heat loss occurred. This article is concerned about the effect of a double glass panel cover on the efficacy of the integrated solar water heater of an absorber made of metals with corrugated shape. A testbed was developed and used to conduct outdoor experiments. Two case scenarios were experimented, without flow rate and with a flow rate. The water temperature variation for both scenarios was observed and recorded for the 140 Liters storage tank. Due to the proposed thermal design enhancement, the temperature of the stored water had increased in both scenarios, compared to previous designs. In other words, the daily thermal efficiency got increased compares to previous designs as the heat losses were reduced due to the double-glazing cover. The results showed that domestic hot water appropriate for human use can be obtained using the proposed integrated solar water heater. Moreover, the present study in comparison with previous studies show increasing in daily thermal efficiency by 4.6%.

Experimental Evaluation of Double Air Pass Solar Collector in Humid Tropical Environment

The present work was focused on the experimental investigation of a double air pass solar collector which was designed and constructed at the Laboratory of Energetic and Thermal Applied of the National School of Agro-Industrial Sciences of the University of Ngaoundere. It consists of a double glazed cover with a surface of 0.47 m², an absorbent plate and a layer of thermal insulation. It allows simultaneous circulation and the same flow direction of the working fluid (air) on both side of the absorber. The experimental tests were conducted outdoor, in natural environment of Ngaoundéré city, during one month period, from 4 to 30 of April, between 9:00 am and 5:00 pm, local time. The research aim was to characterize, on one hand, the local weather conditions (solar radiation, ambient temperature, relative humidity and wind velocity), and on the other hand the collector performance. The solar collector was permanently oriented towards the South and tilted by 45° with respect to the horizontal plane. The analysis of the temperature profiles of different components of the collector showed that the maximum temperature was reached at 2:30 pm, when solar radiation was 1217 W/m² and they were 73.9°C, 61.7°C and 44.7°C for absorber, inner glass and outer glass, respectively. As concerning the outlet temperature of the heat transfer fluid, the analysis of the results shows that it goes up to 58.4°C and 52.2°C, while thermal efficiency was as high as 47.81% and 65.57% when the air flow velocities were setup at 0.5 m/s and 1.5 m/s, respectively.

CFD analysis of the thermal losses on the upper part of a flat solar collector

AbstractTo investigate the reduction of heat losses on the upper part of a flat solar collector, a two‐dimensional study was carried out by CFD analysis using Fluent. For this purpose, the heat transfer behavior in the air gap over a wide range of thicknesses of the latter (1‐20 mm) and the addition of a second glass cover fixed at midheight of the air gap spacing have been investigated. For small thicknesses of the air gap (1‐8 mm), the heat transfer is essentially conductive. An increase in the thickness leads to the intensification of the natural convection which induces high thermal losses. The simulation results have shown that the addition of a second cover glazing leads to the weakening of the natural convection and thus to an average enhancement of the solar collector temperature over the range of thicknesses studied of approximately 17%. The overall thermal losses coefficient is then reduced by an average of 26% compared with the single‐glazed solar collector. They have also shown that the thickness of the air gaps resulting in the minimum overall heat losses is 8 mm and that the thickness of the second glass cover has no significant effect on these results. In addition, this study has highlighted the importance of taking into account the radiation heat transfer in establishing the thermal balance of a flat solar collector. Indeed, this consideration leads to an average decrease of the absorber temperature of about 30%.

Exploitation of an insulated air chamber as a glazed cover of a conventional solar still

AbstractThe countries of North Africa suffer from a serious problem that affects a large number of people. The trouble is the provisioning of drinking water. Several techniques are used but solar distillation; which seems to be an appropriate, economical, and easy solution. Conventional solar distiller is used in the Saharan areas but the yield of this device is low, that's why there are several studies that are focused on improving this distiller. The technique of double glazing gives an increase in the efficiency of a solar collector; hence, the idea of using the same technique in a conventional solar distiller. Two covers of glasses separated by 1 cm, isolated from the four sides was put on a distiller of dimensions 0.5 × 0.5 m. The results show that this technique minimizes the distiller's yield by 56.52% when compared with the conventional solar distiller.

Intensification of a flat solar collector efficiency

An experimental study was carried out to investigate the intensification of the efficiency of a flat solar collector. To achieve this aim, we investigated the effect of the thickness of the air gap between the glazing cover and the plate absorber and the effect of presence of transparent partitions in the air gap. Indeed, when the thickness of the air gap is increased, the natural convection is intensified, which induces high thermal losses on the front part of the collector. The result of this study highlights that thicknesses larger than the reference one, given by the manufacturer, decrease the efficiency, while thicknesses smaller than the reference one increase the efficiency. The presence of transparent partitions in the air gap leads to the weakening of the natural convection and thus to the enhancement of the solar collector efficiency. Two situations were studied. In the first one, only transverse partitions were placed in the air gap; in the second one, longitudinal partitions were added to the transverse ones to form a crossed structure of partitions. The obtained results showed that in both situations the enhancement of the efficiency is significant and that the crossed structure induces the better efficiency.

Experimental and Numerical Simulation of Solar Still for the Production of Drinking Water in Desert Areas of Southern Algeria

Solar distillation is a simple method used for the production of drinking water from saline or brackish water. This method proposes a solution for the production of fresh water in arid and desert areas, where a large solar field is available and also the existence of underground sources of saline water. A solar distiller with a single basin and double slopes is theoretically examined. The theoretical model is based on the resolution of equations of heat and mass transfer dependent on time for glazing cover, water film and absorber basin. For validating the results of the theoretical model, a comparison with the experimental results was carried out. A series of experimental tests on a solar distiller with double slopes in the climatic conditions of Ouargla in Algeria were performed. The tests were carried out on 19th February 2009. The amount of water distilled was 2.7 liters, after a day’s work. The results show that the cooling of the glazing cover leads to increase in the amount of distilled water of about 17% in comparison with the reference case. In addition, we found a good agreement between the results of the theoretical model and the experimental data.

SOME ENGINEERING FACTORS AFFECTING THE PERFORMANCE OF SOLAR POWERED ADSORPTION REFRIGEARTION SYSTEM

In the present study three different collector cover materials, single or, double glazing and Polyethylene-plastic cover materials three different adsorbent material masses 12, 14 and 16 kg were used respectively for the determination of the optimal collector cover material and adsorbent mass proportion to methanol quantity. Collector thermal efficiency as affected by daily incident solar radiations kW.hr/m2/day and their effect on methanol saturation which directly reflected on the coefficient of performance for the refrigeration cycle were studied. Refrigeration load in ton of refrigeration and economical evaluation were also studied. Results showed that daily average solar radiation during these experiments was ranged between 6.6 to 7.9 kW.h/m2.day, the double glass cover material has the largest efficiency than both of single and polyethylene-plastic sheet, the thermal efficiency of single, double glazing and polyethylene plastic sheet cover were30.27%, 39.83% and 30.22% respectively. It is clear that the double glazing cover is the optimal cover material of all studied cover materials. Higher values of C.O.P % and refrigeration load were recorded for the 14 kg carbon mass than that of 12and 16 kg carbon mas.

Study on a high-performance photocatalytic-Trombe wall system for space heating and air purification

This article proposes a novel solar gradient-utilization photocatalytic-Trombe wall system that can realize the dual functions of space heating and removal of indoor formaldehyde. A photocatalytic layer is coated on the internal surface of the glazing cover in conventional Trombe wall system. Under solar radiation, ultraviolet light is absorbed by the photocatalytic layer to activate the photocatalytic oxidation of formaldehyde, and the rest of visible and infrared parts are collected by the absorber plate to heat indoor environment. In this article, firstly, an experimental testing set-up of photocatalytic-Trombe wall was constructed and a full-day experiment was conducted to investigate the performances of air heating and formaldehyde degradation. Secondly, a coupled kinetic, thermal and mass model was derived and verified by the experimental data. Finally, adopting the established model, the seasonal energy saving analysis and economic analysis in Hefei were conducted. Results are: (1) Based on the experimental results, the daily air heating efficiency was 0.351, and daily generated clean air and degradation mass of formaldehyde were 164.0 m3/(m2 day) and 100.0 mg/(m2 day), respectively; (2) Experimental results confirmed the model accuracy within 8%; (3) Compared with the total thermal load reduction of 246.9 MJ/m2 in heating seasons for conventional Trombe wall, photocatalytic-Trombe wall not only has a higher value of 309.9 MJ/m2, but also an additional valuable total generated clean air of 4764.9 m3/m2; (4) Photocatalytic-Trombe wall system takes about 12.1 years to recoup the initial investment only considering the saving electrical by indoor space heating.

Investigation of the Optical Performance of a Novel Planar Static PV Concentrator with Lambertian Rear Reflectors

Due to the demands for energy saving and environmental conservation, the development of sustainable zero-carbon buildings has become an inevitable trend. Building Integrated Photovoltaics (BIPV) is a promising technology capable of producing clean electricity onsite and replacing conventional building materials. This paper designs and investigates the performance of a planar Lambertian reflector-based concentrating BIPV system. A comprehensive 3D ray-tracing simulation was applied to study the optical characteristics of the proposed module. It was found that when the geometric concentration ratio is 2.0, the optical efficiency of the investigated Concentrating Photovoltaics (CPV) module is 62.5% and the radiant flux received by the solar cells is about 1.4 times that of the counterpart module without solar concentrators. Through parametric analyses, it was concluded that the optical performance can be enhanced by selecting a suitable glass thickness and type, integrating the glazing cover with edge mirrors, adjusting the distance between the solar cells and improving the reflectivity of the Lambertian reflectors. Comparative analysis was also conducted for the CPV systems integrated with Lambertian and v-groove rear reflectors under different incident light angles, respectively. It was confirmed that the system integrated with Lambertian rear reflectors shows less angular dependence.

Experimental study of the effect of slit width and slit spacing on the thermal performance of slit-glazed collectors

An experimental study on the thermal performance of slit-glazed collectors was conducted. Here, glass panes were used as slit glazing cover, and the air was blown continuously through the gaps betw...

Thermal performance of solar cooker with special cover glass of low-e antimony doped indium oxide (IAO) coating

Indium, cadmium and tin based transparent conducting oxide (TCO) films have low thermal emissivity values and these are suitable for energy efficient applications where controlling of thermal effect is an important factor. Among these films antimony doped indium oxide (IAO) coated glass has been explored to have resistivity ∼2×10−2Ωcm. The film is homogeneous and good adherence to glass even in large dimensions [500mm×500mm]. This film possesses emissivity ∼0.63 and it has been taken as the standard for the calculation of solar factor (gi) and absorbed solar energy reradiated and convected indoors (Ei) of transparent conducting oxide (TCO) films of 32 types. As calculated, the gi and Ei values of a TCO films are in the ranges 0.77–0.02 and 2.9–59Wm−2 respectively. Attempt has been made to use the IAO coated glass to improve glazing system in solar cooker with the principle that lowering of gi and Ei values would correspond to significant increase of heat insulation property. The thermal performance of solar cooker box having a cover of single layer low-e IAO coated glass was compared with the solar cooker box having a cover of uncoated double glaze soda lime silicate (SLS) glass initially and finally with the same solar cooker box with evacuated glazed cover maintaining vacuum (10−3atm) in the glazing system. Thermal performance of the solar cookers at ambient condition differs due to the variation of heat flow through glass cover with different glazing systems. The performance was promising for the solar cooker box with the cover of single glazed low-e IAO coated glass. The added advantages for domestic usage are low cost of production, relatively light weight and high mechanical durability along with relatively high thermal output.

Smart solar concentrators for building integrated photovoltaic façades

In this study a novel static concentrating photovoltaic (PV) system, suitable for use in windows or glazing façades, has been designed. The developed smart Concentrating PV (CPV) system is lightweight, low cost and able to generate electricity. Additionally, this system automatically responds to climate by varying the balance of electricity generated from the PV with the amount of solar light and heat permitted through it into the building. It therefore offers the potential to contribute to, and control, energy consumption within buildings. A comprehensive optical analysis of the smart CPV is undertaken via 3-D ray tracing technique. To obtain optimal overall optical performance of the novel smart CPV analysis has been based upon all necessary design parameters including the average reflectivity of the thermotropic reflective layer, the glazing cover dimension, the glazing cover materials as well as the dimensions of the solar cells. In addition, a hydroxypropyl cellulose (HPC) hydrogel polymer, suitable for use as the reflective thermotropic layer for the smart CPV system, was synthesized and experimentally studied.

Performance improvement of adsorption solar cooling system

This paper presents the study of a tubular adsorber of solar adsorption cooling machine, driven by flat-type solar collector with three different configurations of glazes: (i) single glazed cover, (ii) double glazed cover and (iii) transparent insulation material (TIM) cover. The modelling and the analysis of the adsorber are the key point of such studies, because of the complex coupled heat and mass transfer phenomena that occur during the working cycle. The adsorber is heated by solar energy and contains a porous medium constituted of activated carbon AC-35 reacting by adsorption with methanol.The simulation technique takes into account the variation of ambient temperature and solar intensity along a simulated day, which corresponds to a total daily insolation of 26,12 MJ/m2 and an average ambient temperature of 27.7 °C. The obtained solution allows to know the daily thermal behaviour of a tubular adsorber. The model is used to study the influence of the solar collector type and its surface on the system's performances COPth and COPs (thermal and solar performance coefficient, respectively). It is found that the type of collector configuration and its surface have a big difference on the system's performance.

Experimental investigation of a solar adsorption refrigeration system working with silicagel/water pair: A case study for Bou-Ismail solar data

The objective of the present work is to build and test a solar adsorption refrigeration device with an adsorbent–adsorbate silicagel–water pair in the weather conditions of Bou-Ismail, Algeria. The refrigeration system proposed in this study consists of three major components: a solar collector (tubular adsorbent bed, reflecting surface, single glazed cover, and 4.5kg of silicagel material), an air-cooled condenser, an evaporator and supplementary system components. The working operation parameters of the cooling adsorption system were tested successfully. Experimental results indicated that the maximum temperature generated varied from 95°C to 117°C, 33°C of average ambient temperature, the condensing temperature varied from 45°C to 53°C, +5°C of minimum evaporator temperature, and the pressure values recorded in the adsorbent bed during the heating desorption period varied from 80 to 100mbar. With a total energy received of around 19MJ/m2, this solar adsorption refrigeration device can provide a solar COP ranging from 0.083 to 0.09. Such results show the practicability of our solar adsorption refrigeration module and that it has a favorable design for use in medical storage in areas without an electrical network (e.g. the Algeria Sahara region).

RETRACTED: Simulation of tubular adsorber for adsorption refrigeration system powered by solar energy in sub-Sahara region of Algeria

Abstract This paper presents a simulation and optimization of a tubular solar collector/adsorber destined for an adsorption refrigeration system developed in El Oued region, which is situated in the sub-Sahara regions of Algeria. The system uses activated carbon–methanol as a working pair, under real climatic data of the region. A theoretical model coupled between heat and mass transfer in adsorbent bed and energy balance in the solar collector/adsorber was presented in Dubinin–Astakhov equation was used to describe the adsorption phenomena. Effect of some important parameters, such as activated carbon types, adsorber tube size, tube wall material and collector glazing cover, on the system performances were investigated. The temperature, pressure and adsorbed mass profiles inside the adsorber have been shown and energy balance for the whole system was determined with relative error 0.014%. The optimized solar collector/adsorber was corresponded to a tube diameter of D = 0.118 m and a number of 8 tubes for filling 1 m 2 double glazed cover collector by about 38.59 kg of activated carbon based on stone coal. This design has a solar coefficient of performance about 0.21 and a collector efficiency η = 44.23% for a tilt angle 20.5° during August at this region. Use of this system, in this region, may be preserve electrical energy of about 28,303 MW h or 2434.058 toe of fossil fuel corresponding to 18396.950 tonne of carbon dioxide emission prevented from being released into the atmosphere.