Solar Cooling Research Articles

Modeling of Materials Heating on Solar Furnace and Cooling of Melt

The possibilities of calculating the rate of heating and cooling of molten materials on the example of pyroxene rocks under the influence of concentrated solar radiation in the Big Solar Furnace are shown. The dependences of the microstructure of the material obtained from the cooled melt on the cooling rate of the melt are analyzed. It is shown that a different method of cooling the melt can achieve different cooling rates: 102 ; 103 and 104 deg/s.

Сонячні абсорбційні системи кондиціювання повітря на основі двоступінчастої регенерації абсорбенту

Розроблені принципові схеми багатофункціональних сонячних систем осушення повітря, теплопостачання (гарячого водопостачання та опалення), холодопостачання та кондиціювання повітря на основі відкритого абсорбційного циклу з прямою (безпосередньою) регенерацією абсорбенту. Такі системи базуються на попередньому осушенні повітряного потоку й наступному випарному охолодженні середовищ у сонячних холодильних системах (СХС) и термовологісної обробки повітря в сонячних системах кондиціювання повітря (ССКП). Авторами використовувався принцип двоступінчастої регенерації абсорбенту. Сонячна система складається з автономних осушно-охолоджувальних блоків, причому кожний ступінь регенерації замкнений на відповідний ступінь абсорбера-осушувача повітря, що дозволяє збільшувати концентрацію абсорбенту від ступеня до ступеня (у діапазоні можливих концентрацій використовуваного розчину бромистого літію LiBr). Розроблені принципові рішення для нового покоління газо-рідинних сонячних колекторів, що забезпечують безпосередню (пряму) регенерацію розчину абсорбенту. Робота тепломаcообмінних апаратів, що входять в осушувальний і охолоджувальний контури абсорбційних систем, базується на принципі плівкової взаємодії потоків газу й рідини з використанням багатоканальної структури із полімерних матеріалів для створення насадки. Попередній аналіз можливостей багатофункціональних сонячних абсорбційних систем виконувався на основі експериментальних даних авторів та моделювання процесів тепломасообміну в основних елементах систем, відносно завдань кондиціювання повітря (ССКП). Показано, що практично для будь-яких, «важких» параметрів зовнішнього повітря вирішення завдань забезпечення його комфортних параметрів може бути виконано без використання традиційної парокомпресорної техніки. Розроблені сонячні системи ССКП відрізняються малим споживанням енергії й екологічною чистотою.

Design of Solar Powered Air Conditioning System

Design of Solar Powered Air Conditioning System

Designing of Solar Air Conditioning for Four Wheeler

Designing of Solar Air Conditioning for Four Wheeler

Parametric Analysis of Solar Heating and Cooling Systems for Residential Applications

In this paper, a parametric analysis of two solar heating and cooling systems, one using an absorption heat pump and the other one using an adsorption heat pump, was performed. The systems under investigation were designed to satisfy the energy requirements of a residential building for space heating/cooling purposes and domestic hot water production. The system with the absorption heat pump was analyzed upon varying (i) the solar collectors’ area, (ii) the volume of the hot water storage, (iii) the volume of the cold water tank, and (iv) the climatic conditions. The system with the adsorption heat pump was evaluated upon varying (i) the inlet temperature of hot water supplied to the adsorption heat pump, (ii) the volume of the hot water storage, (iii) the volume of the cold water tank, and (iv) the climatic conditions. The analyses were performed using the dynamic simulation software TRNSYS in terms of primary energy consumption, global carbon dioxide equivalent emissions, and operating costs. The performance of the solar heating and cooling systems was compared with those associated with a conventional system from energy, environmental and economic points of views in order to evaluate the potential benefits.

Thermoeconomic analysis and optimization of a solar micro CCHP by using TLBO algorithm for domestic application

ABSTRACTIn the present study, a micro solar Combined Cooling, Heating and Power (CCHP) system based on Organic Rankine Cycle (ORC) is thermodynamically and exergoeconomically investigated. Adding a storage tank will lead to the sustainable supply of energy for summer and winter seasons. The model of conservation of energy, conservation of mass, and conservation of linear momentum are applied in order to energy analysis, while a model based on the first and the second laws of thermodynamics are used to exergy analysis. Determining the effective parameters of the system efficiency, including turbine input pressure, turbine inlet temperature, turbine output pressure, and evaporator temperature leads to improve and optimize the system performance. The Teaching–Learning-Based Optimization (TLBO), for the first time in this paper, is employed for both single-objective and multi-objective optimizations of the system for three working fluids (R123, R134a, and R245fa). The accuracy of the proposed model is validated by data presented in three different papers. For the summer season, the values of the energy efficiency, exergy efficiency, and cost rate for R123 working fluid are calculated as 24.81%, 9.94%, and 5383$/year, respectively. The implementation of the multi-objective optimization using TLBO for R123 working fluid improves 27.85% thermal efficiency, 27.66% exergy efficiency and reduces 9.90% of the system cost rate.

Experimental and numerical analysis of seasonal solar‐energy storage in buildings

This paper presents seasonal-energy storage of solar energy for the heating of buildings. We distinguish several types of seasonal storage, such as latent, sensible, and chemical storage, among which the thermochemical storage is used and analysed in this research. In the first part, a laboratory heat-storage tank, which was made in the laboratory for heating, sanitary, and solar technology and air conditioning from the Faculty of Mechanical Engineering, University of Ljubljana, Slovenia, was presented. The experimental model was tested for charging and discharging mode. Two types of numerical models for sorption thermal-energy storage exist, which are microscale and macroscale (integral). For microscale analysis, the analysis system (ANSYS) model can be used to simulate the behaviour in the adsorption reactor. On macroscale or integral scale, TRaNsient SYStem (TRNSYS) model was used to perform the operation of the storages on the yearly basis. In the second part the simulation of the underfloor heating system operation with a built-in storage tank was carried out for two locations, Ljubljana and Portorož. Furthermore, the comparison between a thermochemical and sensible-heat storage was performed with TRNSYS and Excel software. In this comparison, the focus was on the surface parameters of the SCs and volume of the thermal-storage tank for the coverage of the energy demand for selected building. With this analysis, we would like to show the advantage of the thermochemical storage system, to provide greater coverage of the energy demand for the operation of the building, compared with the seasonal sensible-heat storage (SSHS). Such a heat-storage technology could, in the future, be a key contributor to the more environmentally friendly and more sustainable way of delivering energy needs for buildings.

Installation and Operation of a Solar Cooling and Heating System Incorporated with Air-Source Heat Pumps

A solar cooling and heating system incorporated with two air-source heat pumps was installed in Ningbo City, China and has been operating since 2018. It is composed of 40 evacuated tube modules with a total aperture area of 120 m2, a single-stage and LiBr–water-based absorption chiller with a cooling capacity of 35 kW, a cooling tower, a hot water storage tank, a buffer tank, and two air-source heat pumps, each with a rated cooling capacity of 23.8 kW and heating capacity of 33 kW as the auxiliary system. This paper presents the operational results and performance evaluation of the system during the summer cooling and winter heatingperiod, as well as on a typical summer day in 2018. It was found that the collector field yield and cooling energy yield increased by more than 40% when the solar cooling and heating system is incorporated with heat pumps. The annual average collector efficiency was 44% for cooling and 42% for heating, and the average coefficient of performance (COP) of the absorption chiller ranged between 0.68 and 0.76. The annual average solar fraction reached 56.6% for cooling and 62.5% for heating respectively. The yearly electricity savings accounted for 41.1% of the total electricity consumption for building cooling and heating.

Retractable membrane ceilings for enhancing building performance of enclosed large-span swimming stadiums

Ceiling performance of enclosed large-span buildings, i.e., stadiums, airport terminals and swimming pools, is related to safety requirements, working serviceability and energy demands. Conventional plasterboard and/or aluminum plate ceilings of large-span buildings are potential dangerous under earthquake effects and energy-consuming during normal working conditions. To ensure safety performance and manage energy performance, a retractable membrane ceiling is proposed in relation to multiple functions and building complexity. This study concerns an experimental study on overall building performance enhancement of a typical large-span swimming stadium using retractable membrane ceilings. One-parameter and two-parameter analysis are performed to quantify crucial factors.Generally, safety performance of retractable membrane ceilings is validated using drop experiments. The corresponding structural advantages are provided compared with other ceiling systems. Moreover, long-term experimental results show building performance enhancement with membrane ceilings. In detail, one-parameter analysis indicates similar effects of membrane ceiling and air conditioning on temperature performance. A temperature enhancement of 1.56 °C demonstrates the critical influence of membrane ceilings. For two-parameter analysis, different effects of solar irradiance and air conditioning in summer result in more energy consumption. In winter, similar effects of membrane and air conditioning can save more energy than that of solar irradiance and air conditioning.

Coolfacade : Architectural Integration of Solar Cooling Technologies in the Building Envelope

Increasing cooling demands in the built environment present an important and complex challenge for the design of sustainable buildings and cities. Even though the first course of action should always aim to reduce energy consumption through saving measures and passive design; these are often not enough to avoid mechanical equipment altogether, particularly in the case of office buildings in warm climate contexts. Solar cooling technologies have been increasingly explored as an environmentally friendly alternative to harmful refrigerants used in common air-conditioning systems; besides being driven by renewable energy. Nonetheless, building application remains mostly limited to demonstration projects and pilot experiences. The thesis discusses the suitability of solar cooling technologies in terms of their potential for facade integration, exploring current possibilities and identifying main constraints for the development of solar cooling integrated architectural products. The potential for facade integration is assessed considering both the architectural requirements for the integration of building services in the facade development process; and the potential climate feasibility of self-sufficient integrated concepts, matching current technical possibilities with cooling requirements from several climates. Although interesting prospects were identified in this dissertation, important technical constraints need to be solved to conceive fail-tested facade components. Furthermore, several barriers related to the facade design and development process need to be tackled in order to introduce architectural products such as these into the market. The identification and discussion of these barriers, along with the definition of technology driven development paths and recommendations for the generation of distinct architectural products, are regarded as the main outcomes of this dissertation, serving as a compass to guide further explorations in the topic under an overall environmentally conscious design approach.

Cold Storage Capacity for Solar Air-Conditioning in Office Buildings in Different Climates

The building sector accounts for more than 40% of the global energy consumption. This consumption may be lowered by reducing building energy requirements and using renewable energy in building energy supply systems. Solar air-conditioning systems (SACS) are a promising solution for the reduction of conventional energy in buildings. The storage, especially the cold storage, plays an important role in SACS for unstable solar irradiation. In this paper, we took the absorption refrigerating unit as an example, and the solar air-conditioning system of an office building in Beijing was simulated. The accuracy of this model was verified by comparing with the SACS operation data. Moreover, based on the simulation data, the cold storage capacity of the solar air-conditioning system in different climatic regions was studied. The cold storage capacities of SACS in 20 cities distributed in different climate regions were studied systematically. The results simulated by our proposed model will be beneficial to the SACS design, and will enlarge the application of SACS.

Experimental study on the thermal performance of solar air conditioning system with MEPCM cooling storage

Solar powered air conditioning system is a hot issue in the study field of building energy conservation. An experimental platform of solar powered air conditioning with microencapsulated phase change material (MEPCM) cooling storage system was carried out to evaluate the efficiency of the solar powered air conditioning system and the coupled relation with the solar radiation intensity. The outdoor and indoor environmental test system was used to collect the performance parameter data of test room to verify the cooling energy storage effect. The solar air conditioning combined with MEPCM cold storage system which was tested in Chengdu city, China. According to the analysis result, the transient thermal efficiency would decline with the rising normalized temperature difference. The transient thermal efficiency has the same variation trend with the solar radiation. The indoor air temperature of the test room was maintained between 18°C and 22°C. MEPCM cold storage system could maintain the indoor air temperature in the stable range. The energy saving rate of the completed system could reach at 30.5%. The research result could help to improve the study of solar powered air conditioning system and its application.

Solar hybrid air conditioning system to use in Iraq to save energy

The energy saving issues are becoming necessary worldwide, as excessive consumption of energy leads to the consumption of a larger amount of fuel, increases environmental pollution and negatively affects the ozone layer. In Iraq, in particular, the demand for central air conditioning systems and home air conditioners with high electrical capacity has become increasingly clear in the recent years. Air conditioning systems within residential and public buildings, as well as government facilities became a necessity for good internal comfort, which was driven by desertification, high temperature, air pollution and increased population, resulting in increased consumption of electric power and pressing of power plants. Aiming at usage of renewable energy sources, the proposed system uses solar collectors as auxiliary solar thermal compressors and integrate them with air conditioning systems. The proposed solution will increase the cooling system efficiency, reduce electricity consumption and pollution.

Off-Design Modeling and Simulation of Solar Absorption-Subcooled Compression Hybrid Cooling System

The solar absorption-subcooled compression hybrid cooling system (SASCHCS) is potentially an economical solution for high-rise buildings. The hybrid system is subjected to off-design operation frequently, owing to the changes in solar irradiance and cooling demand. However, a large amount of iterations and difficult convergence are encountered in the traditional off-design modeling. Hence, our present study contributes to the development of an off-design model that is exact and can be solved conveniently. A novel modeling method based on the combination of an absorption subsystem described by the characteristic equation and a compression subsystem modeled by the lumped parameter method is proposed. A prototype and corresponding experimental system are developed to verify the model. A good agreement between the theoretical result and test data is displayed. The maximum deviation is less than 4%. Subsequently, the performance of the facility for different operating conditions is simulated and analyzed. We found that the subcooling power relies significantly on the compressor speed, i.e., a reduction by 58.6% when the compressor speed reduces by 80%. In addition, a high temperature and low flow rate of cooling water in the compression subsystem is adverse to the performance of the hybrid system. Our study can serve as the foundation for the operational analysis of the solar absorption-subcooled compression hybrid cooling system as well as promote its development.

Impact of Storage Tank Size and Backup Heating Unit on a Solar Absorption Cooling System

Impact of Storage Tank Size and Backup Heating Unit on a Solar Absorption Cooling System

Enhancement of Hybrid Solar Air Conditioning System using a New Control Strategy

Enhancement of the performance for hybrid solar air conditioning system was presented in this paper. The refrigerant temperature leaving the condenser was controlled using three-way valve, this valve was installed after the compressor to regulate refrigerant flow rate towards the solar system. A control system using data logger, sensors and computer was proposed to set the opening valve ratio. The function of control program using LabVIEW software is to obtain a minimum refrigerant temperature from the condenser outlet to enhance the overall COP of the unit by increasing the degree of subcooled refrigerant. A variable load electrical heater with coiled pipe was used instead of the solar collector and the storage tank to simulate the solar radiation. Experimental data was measured to study the performance of the system. The proposed system was compared with the conventional one. Results show that the COP of the proposed system was higher than the COP of the conventional system by 10 %. In addition, the controlled system saved an electricity of 11.2 %. The optimum opening valve ratio fluctuated between 0.3 and 0.4 when the heater power was 500 W.

Design and experimental analysis of a solar thermoelectric heating, ventilation, and air conditioning system as an integral element of a building envelope

This study presents an innovative concept of a compact integrated solar-thermoelectric module that can form part of the building envelope. The heating/cooling modes use the photovoltaic electrical current to power the heat pump. The experimental analysis was carried out and the results of coefficient of performance were in the range 0.5–1 and 2.6–5 for cooling and heating functions, respectively. The study demonstrates that thermoelectric cooler can effectively be used for heating, ventilation, and air conditioning applications by integrating with solar panels especially in cooling applications. The system is environmentally friendly and can contribute in the implementation of zero energy buildings concept. Practical application: In order to help address the challenge of climate change and associated environmental effects, there is continuous demand for new technologies and applications that can be readily integrated into day-to-day life as a means of reducing anthropogenic impact. Heating, ventilation, and air conditioning, as one of the largest energy consumers in buildings, is the focus of many researchers seeking to reduce building energy use and environmental impact. This article proposes using facades and windows that have an integrated modules of solar photovoltaic cells and thermoelectric devices that are able to work together to achieve heating and cooling effects as required by the building without requiring any external operational power.

Review of Solar Cooling Technologies in the MENA Region

The demand for air conditioning and refrigeration has been increasing due to a rise in the global temperature and the burgeoning world population. Conventional electricity-driven vapor compression cycles (VCCs) use refrigerants, which are harmful to the environment, and are responsible for the consumption of huge amounts of electricity leading to high CO2 emissions. Therefore, solar-driven cooling cycles have great potential to address these issues, and the Middle East and North Africa (MENA) region has an abundant supply of solar radiation. In this study, the research carried out within the MENA region on solar cooling technologies is presented. The solar cooling cycles reviewed are the adsorption, absorption, solid desiccant, liquid desiccant, ejector, and solar electric-driven cycles. The interest over time and across countries in each of these cycles is also discussed. This review shows that interest in solar cooling technologies has increased sharply in the MENA region since late 2000s, and there are several issues like subsidized electricity prices hindering their adoption. In addition, this work shows researches where more investigations are needed.

Comparison of the Thermal Performance of Solar Adsorption Cooling System between Egypt and Morocco

This paper presents the thermal performance of a single stage solar adsorption system. The study includes a thermal performance comparison between two different locations in North Africa (Cairo and Casablanca) under different climate conditions. It was found that the solar fraction of the adsorption system is better under Cairo climate due to the relatively low daily solar radiation of Casablanca compared to Cairo. The solar fraction of the cooling plant was investigated theoretically for six months. The effect of the solar collector area and the mass flow rate of the solar loop on the solar fraction were investigated. The solar fraction was computed for 40 and 20 kW auxiliary heater capacity. The required solar collector area for optimum solar fraction was reduced from 140 to 88 m2 with using 20 kW auxiliary heater and reduced to 46 m2 with the 40 kW auxiliary heater using. The results proved that with the mass flow rate of the solar loop increasing from 0.18 to 1.5 kg/s the collector area required decreases from 110 to 60 m2. This study was performed by the TRNSYS simulation using.

Experimental Study of Hybrid Solar Air Conditioning System in Iraq

In this paper, an experimental study of the thermal performance for hybrid solar air conditioning system was carried out, to investigate system suitability for the hot climate in Iraq. The system consists of vapor compression unit combined with evacuated tube solar collector and liquid storage tank. A three-way valve was installed after the compressor to control the direction flow of the refrigerant, either to the storage tank or directly to the condenser. The performance parameters were collected by data logger to display and record in the computer by using LabVIEW software. The results show that the average coefficient of performance of hybrid solar air conditioning system (R=1) was about 2.42 to 2.77 and the average power consumption was about 1.1 to 1.12 kW when the ambient temperature was about 34.2 to 39.7 ˚C, while the average coefficient of performance of conventional system (R=0) was about 3.23 and the average power consumption was about 1 kW when the ambient temperature was about 30.8 to 34.3 ˚C. It can be concluded that the use of the hybrid solar system in Iraq with its current form could not be saved electricity.