Loading...
Search for:
solar-heating
0.007 seconds
Total 30 records
Experimental evaluation of the effect of boulders and fines in biodegradable organic materials on the improvement of solar stills
, Article Solar Energy ; Volume 247 , 2022 , Pages 453-467 ; 0038092X (ISSN) ; Behshad Shafii, M ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
In this research, for the first time, the effect of primary particles (boulders) and secondary particles (fines) in organic mixtures of coffee, black walnut hull, madder, and tea (which are cheap, abundant, and biodegradable) on the improvement of solar stills' daily efficiency is evaluated as an alternative to metal-based nanofluids. A laboratory still simulator is utilised under laboratory conditions to measure the organic mixture's behaviour accurately. Furthermore, the effect of the concentration of organic mixtures and the particle size of organic materials are investigated, as well as the effect of boulders and fines, independently. In addition, two identical solar still systems are...
CFD simulation of thermal performance of hybrid oil-Cu-Al2O3 nanofluid flowing through the porous receiver tube inside a finned parabolic trough solar collector
, Article Sustainable Energy Technologies and Assessments ; Volume 50 , 2022 ; 22131388 (ISSN) ; Khodaverdian, R ; Doranehgard, M. H ; Chehrmonavari, H ; Xiong, Q ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
In this study, we perform numerical simulations to investigate the thermal and flow characteristics of a parabolic trough solar collector equipped with a porous receiver tube and internal longitudinal fins. The heat transfer medium is a synthetic oil-Cu-Al2O3 hybrid nanofluid. We examine the thermal characteristics of the nanofluid in response to variations in several system parameters. We find that at Reynolds numbers between 5 × 103 and 5 × 105, increasing the volume fraction of Cu nanoparticles can increase the temperature gain at the exit of the receiver tube by 6.4%. Furthermore, the temperature gradient in the cross-section of the collector increases as the direct normal solar...
Application of hybrid nanofluids in a novel combined photovoltaic/thermal and solar collector system
, Article Solar Energy ; Volume 239 , 2022 , Pages 102-116 ; 0038092X (ISSN) ; Salari, A ; Ma, T ; Lu, H ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Because of the low outflow temperature of the conventional photovoltaic thermal systems and lack of electrical production of the solar thermal collectors, a novel combined system is proposed to solve the two mentioned drawbacks. This novel system is achieved by connecting a photovoltaic thermal unit to a solar thermal collector in series. To increase the overall performance of this novel combined system, different hybrid nanofluids include (1) multiwall carbon nanotube-aluminum oxide (2) multiwall carbon nanotube-silicon carbide (3) graphene-aluminum oxide, and (4) graphene-silicon carbide are compared. The investigation is performed based on the three-dimensional simulation, and the...
A comprehensive comparative investigation on solar heating and cooling technologies from a thermo-economic viewpoint—A dynamic simulation
, Article Energy Science and Engineering ; Volume 9, Issue 5 , 2021 , Pages 724-742 ; 20500505 (ISSN) ; Behnam, P ; Abbasi Kamazani, M ; Mohammadi, O ; Kavian, S ; Ahmadi, P ; Rosen, M. A ; Sharif University of Technology
John Wiley and Sons Ltd
2021
Abstract
The yearly thermo-economic performance is dynamically investigated for three solar heating and cooling systems: solar heating and absorption cooling (SHAC), solar heating and ejector cooling (SHEC), and heating and solar vapor compression cooling (HSVC). First, the effects of important design parameters on the thermo-economic performance of the systems to supply the heating and cooling loads of the building are evaluated. The systems are parametrically analyzed with the weather conditions of Tehran, Iran. The results show that the life cycle costs (LCC) of the SHAC and HSVC systems are alike and much lower than those of the SHEC system. The HSVC system exhibits the best performance from...
A novel energy storage system for latent heat recovery in solar still using phase change material and pulsating heat pipe
, Article Renewable Energy ; Volume 163 , 2021 , Pages 2115-2127 ; 09601481 (ISSN) ; Rajabi Ghahnavieh, A ; Shafii, M. B ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
In this study, a latent heat storage unit and built-in condenser were integrated with a solar still. Storage of dissipated latent heat of vapor during the day and using it after sunset prolongs system operation. During the day, the entire solar radiation was consumed to heat the saline water and only the heat coming from the condensation of vapor was stored in the phase change material (PCM). The dissipated heat from the condenser body was transferred to the PCM and stored. Additionally, the existence of PCM on the outer surfaces of the condenser prevented the rise of condenser wall temperature during the day and kept the condenser temperature low. After sunset, the heat stored in the PCM...
Optimal design for solar greenhouses based on climate conditions
, Article Renewable Energy ; Volume 145 , 2020 , Pages 1255-1265 ; Roshandel, R ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Greenhouses require energy in order to provide a proper environment for crop production. Utilizing solar energy in solar greenhouses is a sustainable solution to face this problem. In this study, a solar greenhouse concept is considered, and a dynamic thermal model is developed to predict the inside air temperature. The model is integrated into an optimization procedure to find the optimal greenhouse design that has the best thermal performance by adjusting its structural parameters. This optimization procedure provides a tool to find the optimal solar greenhouse design for each climate condition and predict its performance. For instance, for the case study of Tehran (Iran), the optimal...
A comprehensive comparative investigation on solar heating and cooling technologies from a thermo-economic viewpoint—A dynamic simulation
, Article Energy Science and Engineering ; December , 2020 ; Behnam, P ; Abbasi Kamazani, M ; Mohammadi, O ; Kavian, S ; Ahmadi, P ; Rosen, M. A ; Sharif University of Technology
John Wiley and Sons Ltd
2020
Abstract
The yearly thermo-economic performance is dynamically investigated for three solar heating and cooling systems: solar heating and absorption cooling (SHAC), solar heating and ejector cooling (SHEC), and heating and solar vapor compression cooling (HSVC). First, the effects of important design parameters on the thermo-economic performance of the systems to supply the heating and cooling loads of the building are evaluated. The systems are parametrically analyzed with the weather conditions of Tehran, Iran. The results show that the life cycle costs (LCC) of the SHAC and HSVC systems are alike and much lower than those of the SHEC system. The HSVC system exhibits the best performance from...
Distilled water production with combination of solar still and thermosyphon heat pipe heat exchanger coupled with indirect water bath heater – Experimental study and thermoeconomic analysis
, Article Applied Thermal Engineering ; Volume 176 , 2020 ; Kargarsharifabad, H ; Rahbar, N ; Shafii, M. B ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
The aim of this study is to provide a solution for supplying distilled water used in indirect water bath heaters in the pressure reduction stations. A particular type of distilled water production system consists of a typical solar still and a heat pipe heat exchanger was constructed for recovering heat from the exhaust of an indirect gas heater. The system was tested under the climatic conditions of Semnan-Iran. Experimental results showed that in active type, the average daily production rate of distilled water would be 2.06 times higher than passive type. Also, in the proposed system, the average daily energy efficiency and the exergy efficiency would be 65.5% and 41% higher than the...
A Novel, eco-friendly combined solar cooling and heating system, powered by hybrid Photovoltaic thermal (PVT) collector for domestic application
, Article Energy Conversion and Management ; Volume 222 , 2020 ; Liravi, M ; Babaie Rabiee, M ; Ghodrat, M ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Solar heating and cooling technologies can have a vital role to play in understanding the targets in energy security, economic development, and mitigating climate change. This study aimed to investigate the performance of the combined solar cooling/heating system using a Photovoltaic Thermal collector (PVT) for residential applications. The main advantage of using PVT is the conversion of the maximum amount of solar energy into electricity and thermal energy. In this work, water is used to cool the panel and, consequently, increase the efficiency. The cooling cycle comprises a hybrid ejector-compression refrigeration cycle with two evaporator temperatures. To reduce the effect of the global...
Nano-coated condensation surfaces enhanced the productivity of the single-slope solar still by changing the condensation mechanism
, Article Journal of Cleaner Production ; Volume 265 , 2020 ; Soltani Goharrizi, A ; Ayatollahi, S ; Feilizadeh, M ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Solar stills are considered an environmentally friendly technique to produce fresh water. The condensation surface plays an essential role in controlling the efficiency of the solar still. This main parameter is critically affected by the wettability of the condensation surface that affects the condensation mechanism, namely drop-wise or film-wise condensation. This study aims to enhance the efficiency of solar stills by altering the surface wettability hence changing the condensation mechanism using nanomaterials. In this experimental work, different condensation surfaces were coated by silicone nanoparticles to change the condensation mechanism from film to dropwise. Scanning electron...
Efficiency improvement of solar stills through wettability alteration of the condensation surface: An experimental study
, Article Applied Energy ; Volume 268 , 2020 ; Soltani Goharrizi, A ; Ayatollahi, S ; Feilizadeh, M ; Dashti, H ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
The condensation process is of great importance in many heat transfer devices in which a large amount of energy must be transferred. Furthermore, condensation is a crucial part of energy conversion and affects the energy efficiency of thermal desalination plants and solar stills. During the condensation process in solar stills, an essential part of the energy is transferred through the condensation surface to produce fresh water. Therefore, the condensation surface plays a significant role in the working efficiency of solar stills. The wettability of the condensation surface influences the condensation mechanism, which, in turn, affects the efficiency of solar stills. This study aims to...
Economic and environmental assessment of a solar-assisted ground source heat pump system in a heating-dominated climate
, Article International Journal of Environmental Science and Technology ; Volume 16, Issue 7 , 2019 , Pages 3091-3098 ; 17351472 (ISSN) ; Saidi, M. H ; Abbaspour, M ; Sharif University of Technology
Center for Environmental and Energy Research and Studies
2019
Abstract
In recent years, increasing attention has been paid to the use of renewable energy sources in building sector. The ground source heat pumps are a promising alternative for heating and cooling applications. Despite the high coefficients of performance and significant environmental benefits, their performance may deteriorate over the long-term operation if the annual ground loads are not well balanced. An appropriate solution is the use of hybrid ground source heat pump system through which some portion of the thermal loads can be offset by supplemental components. The aim of this study is to assess the feasibility of a solar-assisted ground source heat pump system for heating a detached house...
Productivity enhancement of solar stills by nano-coating of condensing surface
, Article Desalination ; Volume 454 , 2019 , Pages 1-9 ; 00119164 (ISSN) ; Soltani Goharrizi, A ; Ayatollahi, S ; Feilizadeh, M ; Sharif University of Technology
Elsevier B.V
2019
Abstract
Wettability is one of the most important factors which significantly influences solar still efficiency. Moreover, it determines the condensation mode, i.e., filmwise or dropwise condensation. In the present study, materials with different wettability were applied as the condensing surface to evaluate the effect of wettability on the distillate production of a single slope solar still. To compare the effects of dropwise and filmwise condensation on the condensate yield, the wettability of the condensing surface was changed by applying a nano-silicon solution according to a dip coating technique. All the experiments were conducted at three surface inclination angles. The results revealed that...
Economic and environmental assessment of a solar-assisted ground source heat pump system in a heating-dominated climate
, Article International Journal of Environmental Science and Technology ; 2018 , Pages 1-8 ; 17351472 (ISSN) ; Saidi, M. H ; Abbaspour, M ; Sharif University of Technology
Center for Environmental and Energy Research and Studies
2018
Abstract
In recent years, increasing attention has been paid to the use of renewable energy sources in building sector. The ground source heat pumps are a promising alternative for heating and cooling applications. Despite the high coefficients of performance and significant environmental benefits, their performance may deteriorate over the long-term operation if the annual ground loads are not well balanced. An appropriate solution is the use of hybrid ground source heat pump system through which some portion of the thermal loads can be offset by supplemental components. The aim of this study is to assess the feasibility of a solar-assisted ground source heat pump system for heating a detached house...
Experimental investigation of a solar still equipped with an external heat storage system using phase change materials and heat pipes
, Article Desalination ; Volume 409 , 2017 , Pages 128-135 ; 00119164 (ISSN) ; Shafii, M. B ; Sharif University of Technology
Elsevier B.V
2017
Abstract
In this study, a novel idea of storing the latent heat of condensing vapor in solar stills by means of phase change materials (PCMs) as a thermal storage is experimentally investigated. During the daytime, the generated water vapor by the solar energy, is conducted to an external condenser filled with PCM to be condensed. The wasted latent heat is absorbed by PCM and thereby stored. It is worth noting that there is no direct contact between the saline water and the PCM, therefore, the solar energy is not directly stored in the PCM. In the evening, the energy stored in the PCM is transferred as heat to the saline water by heat pipes and enables the desalination process to continue. Several...
Part load behavior of molten salt cavity receiver solar tower plants under storage mode operational mode
, Article ASME 2016 10th International Conference on Energy Sustainability, ES 2016, collocated with the ASME 2016 Power Conference and the ASME 2016 14th International Conference on Fuel Cell Science, Engineering and Technology, 26 June 2016 through 30 June 2016 ; Volume 1 , 2016 ; 9780791850220 (ISBN) ; Shafiei Ghazani, A ; Taylor, R. A ; Saberi, P ; Sharif University of Technology
American Society of Mechanical Engineers
2016
Abstract
The performance of the tower based concentrated solar thermal (CST-tower) plant is very sensitive to the operation strategy of the plant and the incident heat flux on the receiver. To date, most studies have been examined only the design mode characteristics of the cavity receivers, but this paper significantly expands the literature by considering non-design operating conditions of this important sub-component of the CST-tower plants. A feasible non-design operating conditions of the cavity receivers that was considered in this study is the storage mode of operation. Two practical dynamic control strategies were examined then to find the most efficient approach: fixed solar field mass...
Examination of a novel solar still equipped with evacuated tube collectors and thermoelectric modules
, Article Desalination ; Volume 382 , 2016 , Pages 21-27 ; 00119164 (ISSN) ; Shahmohamadi, M ; Faegh, M ; Sadrhosseini, H ; Sharif University of Technology
Elsevier
2016
Abstract
In this article, a novel solar still which is equipped with thermoelectric modules to utilize the heat of vapor condensation is experimentally investigated. The use of thermoelectric modules as devices for generating electricity from the temperature difference between two environments (hot vapor steam and cold ambient air) as well as taking outstanding advantages of evacuated tubes as collectors with high performances in adverse climatic conditions, led to utilizing of the energy dissipated due to vapor condensation and a considerable increase in the performance of the system. The effect of using the generated electricity to operate a small propeller fan for inducing forced convection was...
Effects of amount and mode of input energy on the performance of a multi-stage solar still: An experimental study
, Article Desalination ; Volume 375 , 2015 , Pages 108-115 ; 00119164 (ISSN) ; Karimi Estahbanati, M. R ; Ardekani, A. S ; Zakeri, S. M. E ; Jafarpur, K ; Sharif University of Technology
Elsevier
2015
Abstract
Effects of the amount and mode of input energy to an active multi-stage solar still were investigated in this work. To control the input energy, an electrical heater controlled by a PLC was utilized to simulate the energy absorbed by solar collectors. The study of the amount of input energy indicated that the freshwater production was a quadratic function of the collector over basin area (CBA) ratio. It was also found that stages 1 to 4 produced about 36%, 26%, 20% and 18% of the overall yield, respectively. Moreover, the effect of employing a thermal energy storage (TES) on the system performance was studied by comparing the mode of feeding energy according to the daily solar radiation...
Year-round outdoor experiments on a multi-stage active solar still with different numbers of solar collectors
, Article Applied Energy ; Volume 152 , 2015 , Pages 39-46 ; 03062619 (ISSN) ; Karimi Estahbanati, M. R ; Jafarpur, K ; Roostaazad, R ; Feilizadeh, M ; Taghvaei, H ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
The present work investigated the outdoor performance of a basin type multi-stage solar still as well as the effect of collector over basin area (CBA) ratio on the distillate production. The effect of CBA was studied in outdoor experiments for the first time. The system consisted of a still coupled with one, two or three flat-plate solar collectors. In order to study the effect of CBA more accurately, the experiments were conducted in both winter and summer. In these experiments, the distilled water production of the multi-stage still was measured during the whole 24. h of a day on an hourly basis. The results revealed that in the winter, the basin coupled to one solar collector (CBA. =...
A new radiation model for a single-slope solar still
, Article Desalination ; Volume 262, Issue 1-3 , 2010 , Pages 166-173 ; 00119164 (ISSN) ; Soltanieh, M ; Jafarpur, K ; Karimi Estahbanati, M. R ; Sharif University of Technology
2010
Abstract
In this paper, a new radiation model for a single-slope solar still has been developed which for the first time takes into account the effect of all walls of the still on the amount of incident solar radiation on the water surface and each wall. In this model, the walls are projected on the cover to calculate the amount of beam radiation received by any components inside the still. This is in contrary to the previous models in which stills' walls were projected on a horizontal surface and their shadows on the water surface and the walls were either neglected or not computed properly. The predictions of the proposed model are compared with the experimental data obtained in the present work...