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The article investigates the dependencies of façade design and construction in the integration of a sustainable solar-powered cooling system based on closed adsorption. The presented work focuses on the possible design variants of the envelope surface of the façade -integrated adsorber. The principle of adsorption cooling is presented and, based on this, architectural options for façade integration are investigated. This is done both constructively and visually. For each variant, the solar gains are summed up and compared with each other. A functionally designed adsorber, similar to a flat plate collector, serves as a reference and starting point for the modifications. It provides the comparative value for the energy evaluation. The modification is limited to the visible surface of the absorber. The texture of the solar adsorbing sheet was changed and the glazing used was replaced by ETFE cushions and by a novel ETFE vacuum panel. Finally, the solar simulation results were integrated into the higher-level system simulation to evaluate the resulting gain in cooling capacity. The results show that the system could generate more than 100 W per installed square metre of adsorber façade. Furthermore, higher solar gains compared to the reference case can be obtained at particular times of the day due to geometry and material changes. However, the modifications always lead to a reduction of the total cooling power. In conclusion, the simulation results reveal that design flexibility is possible, but currently the studied design variants have a lower cooling capacity compared to the solely functionally designed adsorber.

Solar energy is an accessible and sustainable energy source to meet the rising air conditioning demand. This study investigated the performance of solar thermal assisted sorption cooling systems, namely, solar absorption (SABC) and adsorption cooling (SADC) systems. A novel analytical approach to determine the techno-economic potential for specific climate conditions has been developed. The climatic conditions of Malaysia were used as a case study. Both cooling systems were simulated using TRNSYS coupled with VISUAL BASIC and optimized using a multi-objective optimization algorithm implemented in MATLAB. The results show that the COPchiller and collector area have the most significant impact on the performance and primary energy consumption of SABC and SADC systems. On average, 36 % and 27 % of the useful energy gain of solar collectors was converted to the cooling effect in SABC and SADC systems, respectively. Meanwhile, the minimum amount of non-renewable primary energy, the non-renewable primary energy savings ratio, and the least payback period are 0.57 and 0.39, 7.6 % and 7.5 %, and 4 and 9 years, for the SABC and SADC systems, respectively.

Solar cooling systems are widely used in the building sector, as they can utilize low-grade solar energy to reduce carbon emissions. To improve the thermodynamic performance and economic performance of solar cooling systems, solar cooling systems driven by photovoltaic–thermal (PVT) collectors have been widely studied. This paper reviews the recent research on the technological improvement of PVT collectors, the development of thermally driven cooling cycles, and the performance of solar cooling systems driven by PVT collectors. Innovative heat sink structures and the utilization of a high-thermal-conductivity coolant are employed to increase the solar-energy-conversion efficiency of PVT collectors. The use of thermal and mechanical two-stage compression and cascade cooling expands the lower temperature limit of the heat source required for the solar cooling cycle. In addition, specific examples of solar cooling systems driven by PVT collectors are reviewed to explore their thermodynamic and economic performance. Finally, the technical developments in and prospects of different types of PVT collectors and solar cooling systems are explored in an attempt to provide some insight to researchers. This study shows that the PVT collector’s electrical and thermal efficiencies can be improved by 0.85–11% and 1.9–22.02%, compared to those of conventional PV systems and PVT systems based on water cooling, respectively. Furthermore, the lower limit of the heat source temperature for the new thermally driven cooling system expands by 4–20 °C. Finally, the performances of solar cooling systems driven by PVT collectors show a minimum payback period of 8.45–9.3 years, which proves favorable economic feasibility.

In this study, the thermodynamic behavior of a combined cycle power plant with integrated solar-driven inlet air cooling was simulated for Tehran, Phoenix, and Houston during warm-hot seasons. A considerable reduction in the output power was realized during hot ambient conditions due to the lower density of the air and lower mass flow rate to the turbines. The output power decreases from 306.6 to 260.8 MW as ambient temperature increases from 15 to 45 °C. This research focuses on utilizing solar cooling systems to achieve low inlet air temperature to generate high-electricity yields. Four different types of solar collectors and two different absorption chiller units were selected and simulated for each city to achieve the required goal. It was identified that integrating a solar inlet air cooling (SIAC) system can avert the reduction in output power with no impact on efficiency. The humid climatic condition in Houston and the low electricity cost in Tehran posed some challenges in designing a feasible SIAC system. However, by optimizing the solar collectors and cooling capacities, an optimal solution for utilizing inlet air cooling in humid climates is presented. In terms of overall impact, the evacuated flat plate collector (EFPC) coupled with a double-effect absorption chiller displayed the best economic performance among the four variants under study. In Phoenix, this combination can maintain output power during hot days with a DPR of 2.96 years.

Solar-powered adsorption chillers are a particularly interesting alternative to energy-intensive conventional refrigeration systems. Integration of the adsorption chiller with solar collectors is a very promising concept since the increase in solar radiation coincides with the increased demand for cooling. Such a solution is very economical and environmentally friendly. It also fits in with current trends related to energy policy and sustainable development. The article presents the results of tests conducted for a two-bed adsorption chiller integrated with solar collectors. The tests were performed on selected days of the summer period (July and August) at the KEZO Research Centre PAS in Jablonna (Poland). Based on the results obtained, the performance parameters of the adsorption chiller were determined, and the problems associated with the integration of all components of the system were identified and discussed. The values of the determined Coefficient of Performance (COP) and cooling capacity for the tested adsorption chiller are, depending on the day on which the tests were conducted, from 0.531 to 0.692 and from 5.16 kW to 8.71 kW, respectively. Analysis of the test results made it possible to formulate conclusions related to the design of integrated systems of adsorption chillers with solar collectors. [ABSTRACT FROM AUTHOR]

Reliable prediction of solar thermal power is essential for optimal operation and control of renewable energy driven distributed power systems. This paper presents a Convolutional Neural Networks (CNNs) based multivariate approach for forecasting power generation from solar thermal collectors over multiple horizons simultaneously. It also demonstrates an application of solar thermal power generation forecasting in a building cooling system as part of a predictive central controller. Historical data from an evacuated collector field and a single axis tracking collector field have been used to develop the prediction models and assess the performance of the proposed approach. Experimental results show that the proposed approach provides accurate prediction for multiple forecast horizons: MAPE is 2.99%–4.18% for 30 min to 24 h ahead prediction. The proposed approach utilising both historical and predicted future weather data achieves 25%–37% improvements of accuracy compared to its univariate counterpart that uses only lagged power data as input. It also outperforms existing data driven approaches based on NNs, LSTM, and RF, and achieves 5.46%–21.28% statistically significant improvements compared to them. ● Application of Convolutional Neural Networks to forecast solar thermal power output. ● Data cleaning based on an unsupervised ML method (called local outlier factor). ● Input variables selection by applying mutual information. ● Evaluation of prediction model using data for two types of solar thermal collectors. ● 5–21% improvement of prediction accuracy over existing data-driven approaches. [ABSTRACT FROM AUTHOR]

The work aims to analyse an ejector refrigeration system powered with solar energy through serially connected collectors to lower greenhouse gases. The collectors chosen for the work are Scheffler and parabolic collectors with an area of 2.5 m2 and 6 m2, respectively. The steam generated by the collectors is stored temporarily in a 15-l storage tank. The thermic fluid transfers heat between the steam storage tank and refrigerant, and thus the generator temperature increases. This design was intended as an alternate for a traditional 3.5 kW room air conditioner with substantially lower energy consumption. This modified system consumed lesser energy input of about 20–30% than conventional air conditioners. Further, for the same specification, the ejector system has consumed less power of about 2.475 kW than the traditional refrigeration system. [ABSTRACT FROM AUTHOR]

The building sector has great potential for contributing to the 2030 EU goals of decreasing greenhouse gas emissions and increasing production from renewable sources. This is even more important considering the increasing cooling energy needs. Among the available technologies, solar cooling (SC) represents a good alternative to traditional electric chillers. However, its use in residential buildings is still limited. The aim of this paper is to analyse the potential of solar cooling system in multi-family buildings. A dynamic model of a complete SC system with auxiliary components was developed in TRNSYS to meet the energy demand of a representative nearly zero energy multi-family building in Italy. The performance of different system design alternatives was analysed in eight different climates with special focus on energy storages. The results show how solar cooling should be optimally designed and provide quantification of achievable renewable energy ratios and related costs in the different climates. • Weather is a determining factor for the design of Solar Cooling (SC) systems. • Solar Cooling represent a valuable alternative for nZEB space cooling. • Dynamic modelling for optimization of thermal storage is crucial to ensure SC performance. • Global design choices should include cost-optimal analysis. • A best design scenario has been identified economically and energetically. [ABSTRACT FROM AUTHOR]

The article investigates the dependencies of façade design and construction in the integration of a sustainable solar-powered cooling system based on closed adsorption. The presented work focuses on the possible design variants of the envelope surface of the façade -integrated adsorber. The principle of adsorption cooling is presented and, based on this, architectural options for façade integration are investigated. This is done both constructively and visually. For each variant, the solar gains are summed up and compared with each other. A functionally designed adsorber, similar to a flat plate collector, serves as a reference and starting point for the modifications. It provides the comparative value for the energy evaluation. The modification is limited to the visible surface of the absorber. The texture of the solar adsorbing sheet was changed and the glazing used was replaced by ETFE cushions and by a novel ETFE vacuum panel. Finally, the solar simulation results were integrated into the higher-level system simulation to evaluate the resulting gain in cooling capacity. The results show that the system could generate more than 100 W per installed square metre of adsorber façade. Furthermore, higher solar gains compared to the reference case can be obtained at particular times of the day due to geometry and material changes. However, the modifications always lead to a reduction of the total cooling power. In conclusion, the simulation results reveal that design flexibility is possible, but currently the studied design variants have a lower cooling capacity compared to the solely functionally designed adsorber. [ABSTRACT FROM AUTHOR]

A lab-scale two-bed adsorption chiller can be driven by solar energy was designed, constructed and evaluated experimentally in Thermal Engineering Lab, Alexandria University, Egypt. Isotherms characteristics of silica gel that was packed in the two beds were determined depending on the experimental DVS (dynamic vapor sorption) analyzer results. To visualize the sorption phenomena in the two beds and in the evaporator during the adsorption and desorption cycle, a special transparent glass was used as the upper cover for these components. The time variations for the temperatures and pressures at each component were measured, simulated and analyzed. The system performance was experimentally investigated under various operating conditions. The results showed that the specific cooling capacity (SCC) was about 75 W/kg while the coefficient of performance (COP) was 0.42, when the hot water inlet temperature was 75–80 ℃, the cooling water inlet temperature was 25 ℃, and the chilled water inlet temperature was 14 ℃. Effects of adsorption/desorption times and chilled water temperatures (Tch) on the chiller performance were investigated.

Diffusion-absorption refrigeration (DAR) is a cooling technology that uses a three-component working fluid and a thermally-activated bubble-pump for fluid circulation. DAR cooling modules can be manufactured at low cost and entirely driven by thermal energy, making this a promising technology for cold-chain services in off-grid regions. In this work, we investigate the performance potential of an ammonia-water-hydrogen solar-DAR system for application in rural India. In Part I of the investigation, a semi-empirical system model is developed that considers both the steady-state operation of the DAR system and dynamic behaviour during start-up with a solar-thermal heat source. The model is calibrated using experimental data from a laboratory DAR system where heat input rate and system charge pressure are variables that can be adjusted. Under steady-state conditions, the system achieves a maximum coefficient of performance (COP) of 0.25 with a system pressure of 14 bar. However, at the minimum heat input rate of 100 W the system can take up to 2 h or longer for bubble pump activation, prior to which no cooling is produced. In the accompanying paper (Part II), the model is used to investigate the influence of various parameters on system performance and to identify promising areas for improvement. • A model of a solar diffusion absorption refrigeration system is presented. • The system's steady-state and dynamic operation are characterised. • The role of system charge pressure and working fluid concentration are assessed. • The experimentally calibrated model predicts steady-state COP to within ±20%. • The peak heat source temperature during start-up is predicted to within ±10 K. [ABSTRACT FROM AUTHOR]

The diffusion-absorption refrigerator (DAR) is a cooling technology that can be driven entirely by thermal energy. With solar-thermal collectors as the heat source, this technology can provide a zero-emissions solution for essential cold-chain provision in the world's poorest regions. In the accompanying paper, a system model of a solar-driven DAR system was developed for simulating operation under variable solar conditions. In Part II of this study, we apply this model to assess the predicted performance of the system in its intended application: for on-farm refrigeration of harvested crops in rural India. The roles of the working-fluid charge pressure and collector array area for maximum cooling are investigated. A charge pressure of 16 bar is found to be optimal for ambient conditions during the October harvest season in Ahmedabad, with a collector-array area of 1.5 m2 found to be most appropriate for the nominal 70 W cooling-capacity system. However, the time taken to reach the required solar collector temperature for bubble pump activation results in a daily operating period of less than 5 h and a predicted overall solar-to-cooling efficiency of less than 1%. To address these limitations, modifications to various components are considered based on simple assumptions for improving performance. • An assessment is performed of a solar diffusion absorption refrigeration system. • Off-grid cooling operation is simulated for the target region of Ahmedabad, India. • A cooling output of 170 kJ/day is predicted with a solar collector area of 1.5 m 2. • An optimal charge pressure of 16 bar is determined for maximum cooling output. • Modifications to key system components are recommended based on the results. [ABSTRACT FROM AUTHOR]

Ammonia-based solar ejector cooling systems are greener cooling systems than conventional ones, however, the coefficient of performance (COP) of the conventional systems is higher than the Solar-driven ejector ones. This paper aims to evaluate the performance of ammonia-based solar ejector cooling by considering several ejector geometries. The effect of ejector inlet operating conditions (generator and evaporator temperatures) on the entrainment ratio is investigated at several condenser temperatures. The computational fluid dynamic model (CFD model) proposed in this study is validated with experimental and numerical data. The Realizable k–ε model enabled simulating turbulence characteristics with the compressible flow nature across the entire ejector, and the near-wall treatment is employed as a scalable wall function. The results showed that at an evaporator temperature of 15 °C and generator temperature of 90 °C, the highest coefficient of performance of 0.547 was obtained at an area ratio of 6.44. The maximum cooling capacity of 34.93 kW is reached at an area ratio of 6.77. The present findings complement experimental works by guiding the pre-experimental design and providing a better understanding of flow phenomena to improve the efficiency of ammonia-based solar ejector cooling systems and mitigate the environmental effect of cooling operations. • A CFD model is developed and validated to investigate the ejector performance. • The effects of the generator and evaporator temperatures and geometric parameters are studied. • Decreasing the nozzle and the ejector area ratios improves the critical back pressure. • Higher performances can be gained with ammonia when compared with many other refrigerants. [ABSTRACT FROM AUTHOR]

A solar cooling and heating plant with a 1000 l hot water storage tank has been operated since 2018. Two main problems were observed: (1) a fluctuating operation of the absorption chiller due to a high number of stat-up and shut-down procedures; (2) high electricity consumption caused by a low solar fraction SFn of 50.9% during the cooling period. In 2021, the solar plant was retrofitted by employing a shell and tube heat exchanger based on a PCM melting at 64 °C and by adjusting the control strategy. The system performance was evaluated and compared before and after retrofitting based on the operational data in 2021 and 2022. The total number of switch-on times of the chiller shrank by 33.5% and the operation time was increased by 65% in 2022 due to the stable hot water inlet temperature. Contributing to the high heat storage capacity of the PCM storage, more solar thermal energy was utilized and the average SF n reached 75.6% during the cooling period in 2022, leading to a 24.4% reduction in the total electricity consumption compared to 2021. • A fluctuating operation of the absorption chiller was observed before retrofitting due to a higher number of stat-up and shut-down procedures. • A high electricity consumption was caused by a low solar fraction SF n of 50.9% during the cooling period before retrofitting. • After retrofitting, the total number of switch-on times of the chiller shrank by 33.5% and the operation time was increased by 65% due to the stable hot water inlet temperature. • Contributing to the high heat storage capacity of the PCM storage, the average SF n reached 75.6% during the cooling period in 2022, leading to a 24.4% reduction in the total electricity consumption compared to 2021. [ABSTRACT FROM AUTHOR]

This paper proposes the first application of a split-range control technique on a concentrating solar collector to improve an absorption plant production. Solar absorption plants have solar power availability in phase with cooling demand under design conditions. Thus, it is a powerful cooling technology in the context of renewable energy and energy efficiency. These plants need control systems to cope with solar irradiance intermittency, reject irradiation disturbances, manage fossil fuels backup systems and dump closed-loop thermal-hydraulic oscillations. In this work, control techniques are proposed and simulated in an absorption plant in Spain. The plant consists of a concentrating Fresnel solar collector connected to an absorption chiller. The objectives are to operate with 100% renewable solar energy and avoid safety defocus events while reducing temperature oscillations and control actuators effort. Firstly, the current available plant controllers are defined, then two modifications are proposed. The first modification is a split-range controller capable of manipulating both flow and defocus of the Fresnel collector, the second modification is a PI controller to substitute the original chiller on-off controller. The results compare, through validated models, the different control systems and indicate that using both proposed controllers reduces 94% of the sum of actuators effort and 43% of the integral of absolute set-point tracking error compared to the plant's factory pre-set controllers. The suggested controllers increase 66% of energy production and 63% of exergy production. Besides, the split-range technique can be extended to any concentrating solar collector control. [Display omitted] [ABSTRACT FROM AUTHOR]

The rapid growth in smart technology and green energy contributing crucial role in taking our homes into next level. Meanwhile the solar powered thermal systems (STS) are much desired for energy conservation and management of houses. Domestic application of STS will not only reduce electricity consumption but also reduce carbon emission. This paper gives a scoping review on role of various types of STS namely, solar water heating, solar active and passive space heating and cooling, solar thermal water pumping, solar cooking, solar drying, solar distillation, solar green house, solar photovoltaic thermal systems (PVT) and solar thermal energy storage systems in domestic applications. The recent advancements with respect to each type of STS is outlined. Starting from various collectors and materials for STS, each system’s working principle and technological advancements in the view of adopting it to domestic applications are discussed in detail. Also, performance evaluation and role of each different STS in home application is elucidated. The research gaps and potential barriers for adopting STS for domestic homes are explored. [ABSTRACT FROM AUTHOR]

Refrigeration systems claim increasing research attention as the climate crisis intensifies. One of the most well-established viable and feasible solutions is solar cooling, as the necessary cooling energy is produced by exploiting the available solar irradiance. The utilization of solar thermal energy to produce cooling energy by absorption chillers fed by a driving heat source (such as solar energy) to produce cooling power. Existing works in the literature present mainly case studies and simulations for small-scale systems (less than 50 kWc). The case study presented investigates the performance of a single-effect 316 kWc absorption chiller under different renewable-only driving heat source scenarios (solar-driven, biomass-driven, and a hybrid approach). The results indicate a significantly advantageous performance in combined heat generation (solar field and biomass boiler connected in series) compared to the scenarios of biomass or solar energy as a sole heat source. Moreover, an absorption chiller's economic indicators appear more fetching than a centrifugal electric chiller of the same capacity, as the payback period is significantly reduced. The Net Present Value (N.P.V. – over 75% greater in the case of absorption chiller compared to the centrifugal electrical chiller) and Return on Investment (R.O.I.) values are increased in the case of the absorption chiller option (18.03% against 15.24% of the centrifugal electrical chiller). The system described in this paper operates in Eastern Macedonia and Thrace, Greece, and is part of one of the largest self-sufficient energy communities. The case study presented is the first attempt at performance evaluation of a large-scale (more than 250 kWc) cooling system operating in a local energy community. [ABSTRACT FROM AUTHOR]

A comparative study between two solutions which they usually work as a working pairs in pumpless absorption cooling system is achieved analytically with aid of ESS (Engineering Equation Solver) 9.43 software. The pump in this system is replaced by a vertical pipe (lift tube) to ensure the pressure difference between the condenser and the evaporator. These working pairs are Lithium Bromide-Water and Lithium Chloride-Water. The study intends Iraqi summer weather as an ambient circumstances. A thermodynamics model is designed to find the energy and Exergy loss in each of system components. By solving the thermodynamic model, and assuming the same generator, absorber, condenser and evaporator temperatures in each case. It’s found that the system coefficient of performance is relatively the same while the probability of agglomeration in case of Lithium Bromide-Water system is higher because of the large salt concentration. It’s concluded that the Lithium Chloride-Water is most suitable in Iraqi circumstances in spite of high values of total exergy loss which is obtained in case of Lithium Chloride-Water system if it is compared with the exergy loss value in case of Lithium Bromide-Water system.

This study discusses the technical, environmental, and economic feasibility of using absorption chillers driven by solar energy and/or natural gas, in selected shopping malls in Barranquilla, Caribbean region of Colombia. The high solar irradiation and the low prices of natural gas in the cities of the Caribbean region of Colombia are attractive conditions for the use of absorption chillers. To prove the feasibility of absorption chillers in the Caribbean region of Colombia, the use of water/LiBr absorption chillers of 352 kW cooling capacity was investigated considering the cooling loads in selected malls. A thermodynamic model was developed to study the performance of the absorption chiller and evaluate different scenarios proposed. The results evidenced that the absorption chiller could reach a maximum COP and SCOP of 0.77 and 0.52, respectively. The different alternatives could reduce gas emissions between 17% and 76% depending on the cooling load covered by the absorption chillers and driving energy input as compared to the current use of mechanical compression chillers. The economic results indicated that the best scenario, considering a lifetime of 20 years, is the gas-driven absorption chiller with IRR varying from 40% to 54.6% depending on the mall cooling load covered.

Summary: Worldwide cooling energy demands will increase by four times by 2050. Thermally driven cooling technology is an alternative solution to electric heat pumps in removing hazardous refrigerants and harnessing renewables and waste heat. We highlight the advantages of water-stable microporous aluminum-carboxylate-based metal-organic frameworks, or Al-MOFs, as sorbents in the application of producing cold from heat. Here, we synthesize the Al-MOFs with green and scalable processes, which are prerequisites for exploring various industrial and civil applications. A proof-of-concept full-scale adsorption chiller with different Al-MOFs is built up with optimized configurations derived from various characterization techniques. The tested Al-MOFs achieve thermal efficiency above 0.6 and specific cooling power over 1 kW/kg in typical cooling scenarios. Notably, when solar thermal energy is used as the heat source in an outdoor validation, Al-MOFs are weather-resilient solutions that exhibit a stable energy conversion efficiency under fluctuating operating conditions (ambient temperature and solar irradiation).

In contrast to standard vapor compression cooling systems, diffusion absorption refrigeration (DAR) systems are heatdriven and contain no moving parts. Solar diffusion absorption cooling systems can extract heat from a cooling chamber without electricity, enabling food and medicine to be cooled in remote places where there is high solar radiation with unavailable or unreliable electricity. This work aims to model the performance of a solar-driven DAR system with an evacuated tubes collector. The model inputs were the local hourly ambient temperature and solar irradiance for the time of June to August in Ashdod, Israel. Also, collector data, ammonia concentration in the solution, evaporator temperature and the DAR system geometry were considered. The model results showed that as the generator heat input increased rapidly the evaporator cooling capacity was kept almost constant for a given concentration and collector area. This resulted in reduction in the COP values at peak hour. An increase in the collector area had more impact on the heat applied to the generator and not resulted in a significant growth of the cooling capacity, thus, the authors concluded that for optimal COP it is advised to operate the system with lower collector areas. [ABSTRACT FROM AUTHOR]

Solar cooling technologies can play a vital role in renewable energy applications development. Thermoelectric systems have shown promising advantages over traditional refrigeration systems such as high thermal comfort, active adaptability, no moving parts, and refrigerants free. In this work, a novel thermoelectric air-conditioning system (TEACS) driven by photovoltaics (PV) is experimentally and theoretically investigated under the hot climate conditions of Sohag city (30°26′N, 42°31′E), Egypt for air conditioning of a typical small-size office room under different thermal loads. During day time, PV panels produce electricity which utilized to drive the TEACS directly and to charge batteries that store electricity to be exploited during nighttime. Moreover, a numerical model implemented in TRNSYS coupled with MATLAB software is developed to evaluate the performance of the proposed TEACS. The influences of varying the input electric current on the coefficient of performance (COP), cooling capacity, and average air room temperature are also studied. The results showed that a design point with an input current of 2.5 A for a cooling capacity of 30 W could be selected to maximize the cooling performance, in which the COP of the TEACS is found to be 2.2. Moreover, the daily average air temperature of the conditioned room was found to be 23.5, 25.5, 27.5, 28.5, and 30.5 °C for internal thermal loads of 0.0 W, 65.0 W,130.0 W, 195.0 W, and 260.0 W, respectively, at average air intake temperature of 36 °C, daily average input current of 4.28 A and air volume flow rate of 14.4 m3/h. It can be concluded that the TEACS powered by PV could be considered as a proper alternative to the traditional vapor compression systems. [ABSTRACT FROM AUTHOR]

The design of renewable energy systems for Nearly Zero Energy Buildings (NZEB) is a complex optimization problem. In recent years, simulation-based optimization has demonstrated to be able to support the search for optimal design, but improvements to the method that are able to reduce the high computation time are needed. This study presents a new approach based on deep residual learning to make the search for optimal design solutions more efficient. It is applied to the problem of system design optimization for an Italian multi-family building case-study equipped with a solar cooling system. Given a design space defined by set of variables related to Heating, Ventilation and Air Conditioning systems (HVAC) and renewable systems, a machine learning method based on residual neural networks to predict and minimize the objective function characterizing non-renewable primary energy consumptions is proposed. Results have shown that the approach is able to successfully identify optimized design solutions (energy performance improved by 47%) with good prediction accuracy (error smaller than 3%) while reducing the overall computation time and maximizing the exploration of the design space, paving the way for further advancements in simulation-based optimization for NZEB design. • Machine learning can innovate building renewable energy systems design optimization. • A deep residual learning method improves simulation-based optimization performance. • Larger design space exploration and computational effort focused on optimal solutions. • Faster optimization process without losing details of dynamic simulation. • Performance of a solar cooling system increased by 47% with error lower than 3%. [ABSTRACT FROM AUTHOR]

Ejectors are a kind of pump that does not have any moving components. In certain cases, the motor fluid may be a liquid, steam, or another gas. The research focuses on using nano adsorption combined with a multi ejector to fuel a sophisticated nano adsorption power plant, which is equipped with three shapes of steam boiler generators. The simulation was accomplished by implementing it with the cooperation of the two programs MATLAB A and MATLAB B, together with a solid flow. To raise the temperature of the working fluid before it enters the generator, a jet pump is positioned before the generator. To enhance the mass flow rate of vapor going into the ejector, a two-stage adjustable booster was added after the evaporator, which gives low evaporator temperature. A further experiment in which the two-stage adjustable booster was used before the generator to reduce the amount of work done by the generator. The ejector's cooling unit is powered by steam created from many energy sources powered by advanced hybrid heat and power systems, including solar energy and steam produced by the electric steam generator. The different devices are either directly triggered by a thermal source to achieve heating, cooling, or refrigeration. The steam boiler generator is the core of the cooling unit; in this research, various types of steam boiler generators are linked with adsorption units, such as steam-powered solar boilers, gas boilers, solid fuel steam boilers, and electric boilers. Heat exchangers were utilized to transfer heat from the solar chimney to the ejector cooling unit. The impact of various ejector geometries on the advanced cooling unit was studied and simulated for the single, double, and triple nozzle ejector. There were no issues with the more effective cooling unit. This unit performed better than traditional adsorption cooling units, having a greater efficiency. [ABSTRACT FROM AUTHOR]

Maintaining mechanical ventilation has been identified as a potential strategy for reducing the risk of virus infections. However, in hot and humid climatic conditions, delivering fresh air to a building comes at an energy cost and could impact occupant comfort due to the persistent need for simultaneous cooling and dehumidification. In this paper, the performance of a novel hybrid air conditioning system that handles fresh air is studied. In this system, dehumidification is accomplished by a solid desiccant dehumidifier coupled with a cooling coil integrated with the cooling tower of an existing chiller system. Using the data available from an operational desiccant cooling system, a system-level model has been developed and validated to study the potential application of the system in hot and humid climates. The study found that such a system is effective in delivering sensible cooling in all types of climates; thanks to the two-stage cooling in cooling coil and chilled water coils, respectively. However, the system is effective in delivering thermal comfort in regions where the climate has a relatively moderate ambient humidity. For the tropical cities of Darwin, Kuala Lumpur and Bangkok, the system can provide comfortable temperatures, but faces challenges in keeping the humidity within the comfort zone. The system electrical coefficient of performance (COP) is higher than that of refrigerative systems. This system also has the benefit over the refrigerative system of the supply air, which is entirely fresh ambient air and is expected to improve the indoor environmental quality largely.

Growing populations, burgeoning economies, and technology-driven lifestyles demand an increasing supply of energy. The existing energy supply pattern primarily depends on fossil fuels that have initiated climate change–provoking myriad problems. Integration of renewable energy sources in the existing energy supply system is a complex and challenging task keeping in view the depleting fossil fuels and prevailing environmental challenges. The existing cold storage farms are working on traditional compressors and the HVAC system, causing more use of electricity. Similarly, existing data centers and supermarkets are also using conventional refrigerants. These systems also use hazardous environmental refrigerants, which make these systems more dangerous. In the summer season, comfort cooling and refrigeration requirements rise to peak in hot climate areas forcing utilities to supply more electrical energy to meet the demand. Therefore, a solar thermal cooling system employing a solar absorption chiller operated through a hot water stream generated by a solar evacuated glass tube collector with CO2 as a refrigerant is simulated in the TRNSYS® simulation environment. The results are generated for the hot climate of Multan, Pakistan, and the average obtained temperatures of the three rooms, cold storage, office, and kitchen room, were 18.43, 26.25, and 29.83°C, respectively. However, every startup or new idea needs a proper business model before entering into the market. This article offers a complete insight and a future perspective for the reader to develop a precise business model for the commercialization of his or her project. A business model is designed for solar thermal air conditioners for domestic, cold storage, and data centers applications in the world, after reviewing and interviewing manufacturers and customer segment in air conditioning fields. Data were collected through semi-structured one-to-one interviews from a convenient sample of 10 national and international respondents, and their views were thematically analyzed. The implementation of a business model using a case for the Pakistani market is presented. A business model for a solar cooling system utilizing abundant CO2 as a refrigerant is presented in this article. This business model is equally suitable for designing a business model for any renewable energy product in the world.

Solar cooling technologies are becoming increasingly popular. Technological innovation and mass production driven due to its use of renewable energy has led to a significant reduction in the initial cost of investment. However, due to the sporadic nature of solar energy coupled with other technical and economical limitations, it is difficult to solely depend on a solar cooling system. In this study, a solar powered absorption chiller system was mathematically modelled and simulated. Objective of this study was to compare the performance of an absorption chiller system using two backup modes; LPG fired auxiliary heating mode and using an electrically driven vapor compression chiller. Inclined solar collectors were generating the solar power for the system. Solar irradiance on the inclined plan of the solar collector were calculated using ASRC-CIE sky model. Sky model and the absorption chiller with auxiliary heater was validated by dissecting the system into major components and comparing the results with practically logged data. Both configurations were able to meet the cooling requirements. Annual simulations of the two systems showed that both systems could operate with a collector area to cooling power ratio of 2 m²/kWth. [ABSTRACT FROM AUTHOR]

Renewable energies including solar energy requirements for refrigeration and air conditioning are increasingly gaining interest due to the refrigerants friendly to the environment. However, it was found that these technologies have some limitations like the low performance and their high cost. This paper proposes a comparative study of a solar adsorption refrigeration machine. The study consists in determining the influence of thermodynamic parameters of operation on the performance of the system. This is based on a thermodynamic model using different types of adsorbent / adsorbate pairs. The main parameters considered in this study are: temperature of generation, evaporation, maximum heating temperature, condensation pressure as well as the type of the pair used: activated carbon / methanol and zeolite / water. Simulations for different thermodynamic parameters show that the COP is very sensitive to the generation and evaporation temperatures as well as the maximum heating temperature, on the other hand it was slightly influenced by the condensation pressure. The results obtained have shown that the AC / methanol pair is more profitable than the zeolite / water pair. [ABSTRACT FROM AUTHOR]

Modern so‐called renewable energy storage technologies are actually broadening concerns over future sustainability awareness for facing the fossil fuel scarcity crisis. We need to be more innovative in using and storing the free‐cost energy sources that are essentially needed to be adopted in our modern societies. Several initiatives have been addressed for renewable energy storing capabilities. Recently, one of the areas gaining scientists attention is the solar energy storage via phase change materials (PCMs). PCMs are those materials that signified by storing surplus solar energy and releasing the accumulated energy collected when it is in deficiency for its later use in which they are situated. This ambition is based on capturing the heat provided by the solar field for useful utility applications, such as power production, solar cooling, and domestic water heating. This review is aiming to assist the researchers by providing an overview of PCMs basics, classifications and their technological applications. Additionally, a detailed information and literature reviewed toward enhancing the thermal conductivity of PCMs' systems via numerous nanomaterials additions are discussed and their various thermal energy storage applications are overviewed. The pros and cons of nanoadditives PCM are also discussed. Future perspectives and PCMs trends are provided. [ABSTRACT FROM AUTHOR]

This study applies the microchannel membrane-based module to develop a novel modular and compact thermal energy storage system to meet building requirements with solar or waste thermal energy in a low-carbon path. Compared to traditional systems, the novel system demonstrates significant improvements, with the charging and discharging rates increased by 2 and 3 times. The energy storage efficiency is enhanced from 0.470 to 0.772, while energy storage density based on fluid and setup volume are increased by 78.62% and 120.90% respectively. The charging/discharging rate and solution concentration glide increase continuously as the heat source temperature rises from 75 °C to 100 °C, leading to continuous increases in energy storage density and efficiency. As increasing channel length, width, number, and module number, or decreasing channel height improves the charging/discharging rate. Energy storage density can be enhanced by augmenting the channel height and width, increasing the quantity of both channels and modules, or diminishing the channel length. Conversely, smaller channel dimensions and larger channel heights are advantageous for higher efficiency. The scaling up combined with customizability, and popularization of the proposed compact modular microchannel membrane-based absorption thermal energy storage system would be required for mass uptake of this innovative solution in building cooling applications. • Microchannel membrane-based absorption energy storage system (MMATES) is proposed. • MMATES improves the charging and discharging rates by 2 and 3 times compared to ATES. • Energy storage efficiency is enhanced by MMATES from 0.470 to 0.772 • Energy storage densities based on fluid and setup volume are all enlarged by MMATES. • Impacts of heat source temperature and module geometries on MMATES are studied. [ABSTRACT FROM AUTHOR]

• This paper presents an experiment on solar-powered air conditioning. • The study compares two scenarios: on-grid and off-grid, offering insights into their respective performances. • Evaluation metrics include solar fraction, energy consumption, and operational time fraction. • The solar-powered air conditioning system exhibits superior performance under higher demand and elevated temperatures. • The economic viability of the system is attractive, enhancing its appeal and potential for widespread adoption. Air conditioning is vital in maintaining indoor comfort and improving air quality, particularly in regions with high temperatures and humidity. However, the increasing demand for air conditioning has significant implications for energy consumption and the environment. Solar air conditioning can play a vital role in mitigating such impacts. This study presents an experimental setup that utilizes a solar photovoltaic system to power an air conditioning unit. The system is installed in a 36 m2-research lab at The University of Jordan, equipped with PV panels with a capacity of 2.67 kWp, a battery pack, a charge controller, an inverter charger, and an air conditioning unit. Two testing scenarios are conducted: an on-grid system connected to the electrical grid and an off-grid system operating independently. A clear sky day and a partially cloudy day were selected for each scenario in testing. The results were evaluated based on the solar fraction, energy consumption, and operational time fraction (OTF). The solar fraction was found to be higher during periods of higher demand and ambient temperature, and the average OTF was 70 % for all trials. In off-grid trials, the system had maintained operation solely on PV power during the studied load profile in the clear sky day. In contrast, limitations in charging power caused system shutdown in the partially cloudy trial. An economic analysis for the local payback period (PBP) was conducted based on the Hourly Analysis Program and PVsyst software simulation, which shows an attractive simple local PBP for on-grid and off-grid systems of 6.91 and 6.4 years, respectively. [ABSTRACT FROM AUTHOR]

As a novel solar cooling facility in the building with many floors, the solar absorption-subcooled compression hybrid cooling system (SASCHCS) is not evaluated economically and environmentally. Consequently, the paper mainly contributes to the above-mentioned study to show the potential of the SASCHCS. The evaluation, performing by the dynamic simulation based on the monthly typical cooling demand and meteorological data, is by the comparison of SASCHCS and the solar PV cooling which is thought to be the most economical solution recently. It is found that the SASCHCS is economically better than the solar PV cooling though the saving of CO2 emission in the SASCHCS is less. Besides, the SASCHCS becomes more economical and attractive as the performance of its compression subsystem is poor. The payback period of the SASCHCS drops to 17.6 yr when the performance of compression subsystem comes down by 20%. The paper is helpful to promote the application of the SASCHCS.

Solar-powered adsorption chillers are a particularly interesting alternative to energy-intensive conventional refrigeration systems. Integration of the adsorption chiller with solar collectors is a very promising concept since the increase in solar radiation coincides with the increased demand for cooling. Such a solution is very economical and environmentally friendly. It also fits in with current trends related to energy policy and sustainable development. The article presents the results of tests conducted for a two-bed adsorption chiller integrated with solar collectors. The tests were performed on selected days of the summer period (July and August) at the KEZO Research Centre PAS in Jablonna (Poland). Based on the results obtained, the performance parameters of the adsorption chiller were determined, and the problems associated with the integration of all components of the system were identified and discussed. The values of the determined Coefficient of Performance (COP) and cooling capacity for the tested adsorption chiller are, depending on the day on which the tests were conducted, from 0.531 to 0.692 and from 5.16 kW to 8.71 kW, respectively. Analysis of the test results made it possible to formulate conclusions related to the design of integrated systems of adsorption chillers with solar collectors.

Air conditioning systems (ACSs) represent one of the main demands for electricity in residential, commercial, and industrial buildings. The use of a photovoltaic air conditioning unit (PVACU) represents an attractive application to this demand for reasons such as environmental concerns and the match between diurnal cooling load and solar resource. A PVACU consists of a photovoltaic generator (PVG) that supply an ACS through direct current to direct current and frequency converters, without energy storage. This system considers the natural adjustment of the ACS cooling capacity according to the PVG power. Modeling the ACS, the PVG, and the thermal load (TL) makes possible to evaluate PVACU performance. For this, a small library's TL and an ACS supplied by a PVG were used as case study. The PVG installed capacity assumes values of 700, 1000, and 1400 Wp. The simulation results show that the PVACU with a 1400 Wp PVG would be sufficient to regulate internal temperature within international comfort standards in the range of 20 °C to 24 °C. According to the data obtained in the simulations, it was possible to conclude that the PVACU has a large potential to be used in air conditioning of other environments in regions with Amazonian climatic conditions. [ABSTRACT FROM AUTHOR]

A lab-scale two-bed adsorption chiller can be driven by solar energy was designed, constructed and evaluated experimentally in Thermal Engineering Lab, Alexandria University, Egypt. Isotherms characteristics of silica gel that was packed in the two beds were determined depending on the experimental DVS (dynamic vapor sorption) analyzer results. To visualize the sorption phenomena in the two beds and in the evaporator during the adsorption and desorption cycle, a special transparent glass was used as the upper cover for these components. The time variations for the temperatures and pressures at each component were measured, simulated and analyzed. The system performance was experimentally investigated under various operating conditions. The results showed that the specific cooling capacity (SCC) was about 75 W/kg while the coefficient of performance (COP) was 0.42, when the hot water inlet temperature was 75–80 ℃, the cooling water inlet temperature was 25 ℃, and the chilled water inlet temperature was 14 ℃. Effects of adsorption/desorption times and chilled water temperatures (T ch) on the chiller performance were investigated. [ABSTRACT FROM AUTHOR]

• Solar cooling/heating extended to cover over-night demand with storage systems. • A mixed tank, with PCMs for heating and cooling, is used. • Longer times can be achieved with PCM-based storage tanks than water tanks. • A reduction of more than 80% in electricity compared with compression cycle. • Heating can be provided for the whole night. The performance of different thermal energy storing systems to provide over-night air-conditioning for a limited space in an institutional building in south Spain are compared with conventional air-conditioning (both for refrigeration and heating). In summer, the storage tanks are charged with a solar-assisted absorption chiller during day-time, and used to cover the over-night demand, whereas in winter a heat exchanger is used during the day to charge the tanks. Thermal energy has been stored in two chilled water tanks (with total capacity of 5000 L) or in two tanks (total volume 4000 L) containing two phase change materials (PCM): a PCM with melting point of 10 ° C for refrigeration, and a PCM with melting temperature of 46 ° C for heating. Our results show that the storing in PCM is more convenient, providing air-conditioning service for approximately 4 h 30 min in refrigeration, with a significant reduction of the electricity consumption with respect to the conventional system. The chilled water tanks can cover the demand for 4 h (scaled down to 3 h 12 min if the capacity is 4000 L), with even lower electric consumption. In winter, on the other hand, the tanks can cover fully the demand of overnight heating. Our results prove the viability of thermal storing, in particular using PCM, to extend the application solar cooling and heating to night-time, which is economically feasible, in a fully operational building. [ABSTRACT FROM AUTHOR]

Reduction of the green-house effect can be obtained by reducing the emissions of CO2. One of the technologies that contributes to this purpose is using solar cooling systems. An example of such systems is Lithium Bromide Absorption Chillers-Driven by Hot Water (LiBr/H2O absorption chillers). These chillers are normally powered by solar collectors (ordinary plate or evacuate tubular), which are widely accessible. This paper includes a review of previous experimental and theoretical studies on the effect of single cooling absorption systems. In addition, new proposals regarding the design of the solar collectors, supporting systems for energy and cooling methods will be provided. Furthermore, the present paper also summarizes the major double influence of the cooling absorption systems, add to the two-stage and half-effect absorption coolers. The influence of double cooling absorption systems using solar power could be considered for the buildings with more cooling capacity requirements, but with structure of space restrictions. However, for these cases is important to consider the direct irradiation, which needs high levels. For dry regions with water shortage, half-absorption and two-stage absorption coolers are more suitable. Solar-powered cooling systems designs should follow and incorporate standard rules based on the characteristics of various areas in order to be applicable on a large scale. [ABSTRACT FROM AUTHOR]

In this study, a dynamic model is proposed to simulate a conventional intermittent solar adsorption cooling system in Adrar region located in southern Algeria. The system working with activated carbon and methanol. The model describes the instantaneous mass and heat transfers for each system component during different phases. The numerical fourth-order Runge–Kutta method was used to solve the mathematical model. The validity of this model has been tested by comparing it with the experimental data, a good agreement was obtained. System performance was evaluated using real meteorological data provided by the weather station. Results showed that the amount of energy received by the adsorber surface is 28.11 MJ/m2, this energy allowed the system to produce 4 kg of ice mass for a typical sunny summer day. The solar coefficient of performance corresponding is 8% and the cycle coefficient of performance is 42% with the adsorber efficiency of 20%. The influence of some key parameters on the cooling capacity was also studied in detail. [ABSTRACT FROM AUTHOR]