Solar Cooling Research Articles

太阳能光伏电池板冷却及发电效率的研究

太阳能光伏电池板冷却及发电效率的研究

Experimental analysis of thermal energy storage by phase change material system for cooling and heating applications

International Energy Agency Solar Heating & Cooling programme states the fact that space heating and cooling demand account for over 75% of the energy consumed in single and multi-family homes. By avoiding conventional methods for thermal storage, phase change materials (PCMs) provide heat storage and provide nearly constant temperature and at much higher energy storage densities. This technology can meet up to maximum of this demand depending on the region’s climate. Active and passive systems are used for this purpose. This study belongs to passive system, night ambient temperatures and solar energy for cooling and heating of buildings. PCMs could be stored with building substance used in floor to enhance their thermal storage capacity. Compare to other principles for thermal energy storage latent heat storage is competent because of small changes in temperature leads to storage density, promising technologies with low heat losses and attractive prices. This research is carried out to assess the performance of air based PCM storage system for cooling and heating of building. The execution of the concentrated on Phase change material storage system was noted maximum when melting point of Phase change material was 22.5°C in winter season and 28.8°C(∼29°C) during summer period. Summer, whereas 26.8°C was found during remaining part of the year. When the temperature goes below 26.8°C, cooling capacity of system is more as compare to heating capacity. Study also concludes that the effect of melting point of PCM has a great effect on cooling in summer period and its storage can be used in winter season.

Investigation of Solar Cooling Cogeneration Plant

The deficiency in the energy for the space cooling is overcome by solar energy. Still the input energy is minimized by integrating both power and cooling cycle in common platform, such as working fluid, component and working parameters. The aqua-ammonia is used in both power cycle and vapor cooling cycle. The generator is common for cycles for the production of ammonia vapor. The analyses are made to find out the operational parameters for the cooling cogeneration cycle with solar as source. The analyses are done for the proposed cycle with various atmosphere temperatures. At absorber concentration of 0.42 and turbine inlet concentration of 0.90, with solar collector exit temperature of 155°C and atmosphere temperature of 30°C the generated power and cooling are 21.88 and 215.79 kW, respectively. The power and cooling output range can alter by varying turbine inlet concentration and temperature.

TRNSYS simulation for solar-assisted liquid desiccant evaporative cooling

ABSTRACTRecently, desiccant cooling systems are well thought of as a competent method for controlling the water content in the air. A solar flat-plate collector has been used as it decreases the dependency on non-renewable resources. Solar-aided liquid desiccant systems have been used to reduce the dependency of air-conditioning systems on non-renewable sources of energy. Manipal’s humid and searing climate provides certain benefits in setting up such a system. The suggested system has reliability and equipment life and also takes complete advantage of the available solar energy for the renewal of the liquid desiccant. TRNSYS simulation is used to predict the efficiency and feasibility of the system. The temperature and energy-load variations were successfully obtained. An effective simulation was developed whereby the solar air conditioning of a room was indicated.

Modeling and simulation of a desiccant assisted solar and geothermal air conditioning system

Abstract In this study, we investigated a desiccant assisted air conditioning system that includes borehole heat exchangers for direct cooling and solar energy for desiccant regeneration. We developed a system model and ran simulations of this model for five cities in the United States. Our research shows that the system can provide sufficient latent and sensible cooling throughout the cooling period. Depending on the location, a maximum Seasonal Energy Efficiency Ratio of up to 7.66 (kW/kW) is achieved. We further investigated the utilization of borehole heat exchangers within a desiccant assisted hybrid air conditioning system by comparing their energetic, economic and environmental performance to a vapor compression chiller that utilizes R410A as refrigerant. We found that electricity savings of more than 50% and CO2 equivalent emission savings of up to 91% are possible, while the geothermal system is not cost competitive at most of the investigated locations.

大学施設における太陽熱併用空調・換気・給湯システムの運用実績

大学施設における太陽熱併用空調・換気・給湯システムの運用実績

Energy saving potential of a solar assisted desiccant air conditioning system for different types of storage

In this study, the performances of a solar energy assisted desiccant air conditioning system with different types of storage materials are numerically investigated. In this study four types of storage materials (paraffin wax, stearic acid, capric‐palmitic, and CaCl2·6H2O) are used to obtained the better storage materials can be use for a solar energy assisted desiccant air conditioning system. The numerical results show that, at the same operating conditions the average percentage of energy saving potential approximately reached to 75.86%, 78%, 72.4%, and 64.6% for using paraffin wax, stearic acid, capric‐palmitic and CaCl2·6H2O as a thermal storage materials, respectively as compared to the case without storage materials and solar energy. The life cycle savings reached to 1727.5, 1997.6, 1766.1, and 1534.6 $for using paraffin wax, stearic acid, capric‐palmitic and CaCl2·6H2O as a storage materials, respectively at the same energy cost of 0.039 $/kWh. The results shows that the stearic acid represents a better thermal storage materials use in a solar assisted desiccant air conditioning with thermal storage materials. © 2017 American Institute of Chemical Engineers Environ Prog, 37: 1448–1454, 2018

Techno-Economic Analysis of Solar Absorption Cooling for Commercial Buildings in India

Space cooling and heating always tends to be a major part of the primary energy usage. By using fossil fuel electricity for these purposes, the situation becomes even worse. One of the major electricity consumptions in India is air conditioning. There are a lot of different technologies and few researchers have come up with a debate between solar absorption cooling and PV electric cooling. In a previous paper, PV electric cooling was studied and now as a continuation, this paper focuses on solar thermal absorption cooling systems and their application in commercial/office buildings in India. A typical Indian commercial building is taken for the simulation in TRNSYS. Through this simulation, the feasibility and operational strategy of the system is analysed, after which parametric study and economic analysis of the system is done. When compared with the expenses for a traditional air conditioner unit, this solar absorption cooling will take 13.6 years to pay back and will take 15.5 years to payback the price of itself and there after all the extra money are savings or profit. Although the place chosen for this study is one of the typical tropical place in India, this payback might vary with different places, climate and the cooling demand.Article History: Received May 12th 2017; Received in revised form August 15th 2017; Accepted 1st Sept 2017; Available onlineHow to Cite This Article: Narayanan, M. (2017). Techno-Economic Analysis of Solar Absorption Cooling for Commercial Buildings in India. International Journal of Renewable Energy Development, 6(3), 253-262.https://doi.org/10.14710/ijred.6.3.253-262

Techno-Economic Analysis of Solar Absorption Cooling for Commercial buildings in India

Space cooling and heating always tends to be a major part of the primary energy usage. By using fossil fuel electricity for these purposes, the situation becomes even worse. One of the major electricity consumptions in India is air conditioning. There are a lot of different technologies and few researchers have come up with a debate between solar absorption cooling and PV electric cooling. In a previous paper, PV electric cooling was studied and now as a continuation, this paper focuses on solar thermal absorption cooling systems and their application in commercial/office buildings in India. A typical Indian commercial building is taken for the simulation in TRNSYS. Through this simulation, the feasibility and operational strategy of the system is analysed, after which parametric study and economic analysis of the system is done. When compared with the expenses for a traditional air conditioner unit, this solar absorption cooling will take 13.6 years to pay back and will take 15.5 years to payback the price of itself and there after all the extra money are savings or profit. Although the place chosen for this study is one of the typical tropical place in India, this payback might vary with different places, climate and the cooling demand.Article History: Received May 12th 2017; Received in revised form August 15th 2017; Accepted 1st Sept 2017; Available onlineHow to Cite This Article: Narayanan, M. (2017). Techno-Economic Analysis of Solar Absorption Cooling for Commercial Buildings in India. International Journal of Renewable Energy Development, 6(3), 253-262.https://doi.org/10.14710/ijred.6.3.253-262

Preparation, characterization and thermal regulation performance of cement based-composite phase change material

Thermal behavior of a building mass can be enhanced using phase change materials (PCMs) as latent heat thermal energy storage (LHTES) materials. Such type thermal enhanced construction materials can be used for passive solar heating, ventilating and air conditioning (HVAC) purposes in building envelopes. This work was focused on development, characterization of LHTES properties and establishment of thermal performance of a cement-based composite PCM (Cb-CPCM) plaster for low-temperature LHTES targets in buildings. The eutectic mixture of capric acid(CA)-myristic acid(MA) was absorbed as 28wt% by cement through vacuum embedding method. The chemical structures and morphology cement/(CA-MA) composite and its pure components were investigated by FT-IR, XRD and SEM techniques. The LHTES characteristics of the produced Cb-CPCM were determined by DSC analysis. The DSC results indicated that the form-stable Cb-CPCM melted and solidified at 21.13 and 17.90°C and had corresponding LHTES capacities as 41.78 and 39.56J/g, respectively. The TGA results and cycling test revealed that the Cb-CPCM had high thermal resistance, long-term cycling chemical stability and reliability. Furthermore, two cubic test rooms were built with/without Cb-CPCM to compare thermo-regulating performance in laboratory-scale. The temperature difference between the indoor temperatures of the cubes was measured as averagely 0.78°C during heating period. All results exhibited that the prepared Cb-CPCM could be considered as a potential composite PCM for low-temperature HVAC intentions in buildings.

Comparative Study on Implementing Home Air Conditioning for Passenger Carriages in the Indonesian Railway

Passenger comfort is important in railway transport system. The train operator company in Indonesia would like to increase passenger comfort by installing home air conditioning into all existing carriages of the economy train. The air conditioning is expected to give better passenger convince. Therefore, the aims of this research are to know the cooling load and compare characteristic between home Air Conditioning (AC) and train AC. The cooling load calculation is analyzed using Cooling Load Temperature Difference (CLTD)/Solar Cooling Load (SCL)/Cooling Load Factor (CLF) method. Comparison between both home air conditioning and train air conditioning are discussed to identify the benefits and drawbacks of each type. The total heat that needs to be removed from a passenger carriage with home AC is 104,334 Btu/h, while the total cooling capacity of home AC is 75,000 Btu/h. The passenger carriages with train AC have cooling capacity 119,100 Btu/h to remove heat 11,5290 Btu/h. The Energy Efficiency Ratio (EER) value of most home AC is higher than train AC, installation time of home AC is shorter than train AC, total cost for 20 years period of home AC is more than train AC. There is no guarantee for home AC, so everything that happens to it will become the full responsibility of train operator company. The train AC control system is more effective than the home AC. No fresh air is permitted to circulate within the home AC system hence, the same air is repeatedly processed in the system. Implementing home air conditioning in the existing passenger carriages is worthwhile for short time period in the goal to increase and improve the level of service provided by giving better comfortability to the passenger.

太陽熱のパッシブ利用に関する研究 : 第2報-ダブルスキンの性能評価

太陽熱のパッシブ利用に関する研究 : 第2報-ダブルスキンの性能評価

潜熱蓄熱材を適用した蓄熱ブラインドによる日射利用空調システムに関する研究 : 第1報-ダブルスキン内に設置した蓄熱ブラインドの日射遮蔽効果及び夜間換気駆動力

潜熱蓄熱材を適用した蓄熱ブラインドによる日射利用空調システムに関する研究 : 第1報-ダブルスキン内に設置した蓄熱ブラインドの日射遮蔽効果及び夜間換気駆動力

実験計画法を用いた太陽熱冷暖房・給湯システムの因子分析による省エネルギ効果と経済性に関する研究 : 第1報-実験計画の概要

実験計画法を用いた太陽熱冷暖房・給湯システムの因子分析による省エネルギ効果と経済性に関する研究 : 第1報-実験計画の概要

実験計画法を用いた太陽熱冷暖房・給湯システムの因子分析による省エネルギ効果と経済性に関する研究 : 第3報-省エネルギ効果と経済性の検討

実験計画法を用いた太陽熱冷暖房・給湯システムの因子分析による省エネルギ効果と経済性に関する研究 : 第3報-省エネルギ効果と経済性の検討

実験計画法を用いた太陽熱冷暖房・給湯システムの因子分析による省エネルギ効果と経済性に関する研究 : 第2報-シミュレーション結果と分析

実験計画法を用いた太陽熱冷暖房・給湯システムの因子分析による省エネルギ効果と経済性に関する研究 : 第2報-シミュレーション結果と分析

Aerogel-based solar thermal receivers

In any solar thermal application, such as solar space heating, solar hot water for domestic or industrial use, concentrating solar power, or solar air conditioning, a solar receiver converts incident sunlight into heat. In order to be efficient, the receiver must ideally absorb the entire solar spectrum while losing relatively little heat. Currently, state-of-the-art receivers utilize a vacuum gap above an absorbing surface to minimize the convection losses, and selective surfaces to reduce radiative losses. Here we investigate a receiver design that utilizes aerogels to suppress radiation losses, boosting the efficiency of solar thermal conversion. We predict that receivers using aerogels could be more efficient than vacuum-gap receivers over a wide range of operating temperatures and optical concentrations. Aerogel-based receivers also make possible new geometries that cannot be achieved with vacuum-gap receivers.

Numerical Investigation of Silica Gel-Water Solar Adsorption Cooling System with Simulink

This paper aims to study a numerical model of an adsorption chiller driven with solar energy that is confronted to experimental measurements. This article deals with numerical study of refrigeration systems using a pair of silica gel and water with simulink. The results include the temperature of desorber, the temperature of chilled, cooling and hot water, temperature of two adsorption/desorption beds, condenser and evaporator, the refrigerant saturation pressures in the two compartments and the time variation of water uptake in two adsorbent beds.

Thermal Analysis of a Solar Cooling Adsorption System by a Dynamic Model

Abstract—In this paper is shown the possibilities to implement an energy solar system, without auxiliary elements, made to cool. The new technologies (vacuumpacked tube, tanks of build-up with variable volume, etc.), allow the possibility to obtain easily a stand-alone refrigerating system. Today it is always more and more the case where during the summer season there is a surplus of thermal energy whose use is to be assigned within the energy optimization system. The most immediate solution to this problem is the ability to produce cold by means of simple adsorption solutions, thus contributing to the cooling problem with low COP values. The most beneficial adsorbent both for its thermal/physical and low cost is the silica gel, a polymer of silicon dioxide, commonly used for its dehydrating properties, especially in the preservation of electronic material [1,3,13].
 In this study we have developed a dynamic model with the software trnsys to verify the obtaining of appropriate warm fluid for an innovative cooling system absorption with gel of silica and water and it is tested on a real building as case study.
 The dynamic model analyzes the performance thermodynamic balance of a small size system has been made (about 20-50 kW), adequate to cool a Building of 900 sq m. and allow to assess the conformation (surface, storage volume, etc.). of a new generation solar power plant is able to guarantee a continuous operation during the summer period [2].
 We have tested a solar cooling system with solar vacuum collectors on a real Building with Meteo data of three Cities as Rome Milan and Tunisi and we have tested the model comparing the results obtained.
 The model in fact allows to make a preliminary design of principal part of the plant and to evaluate function cost-benefit of a complex investment for innovative technology The interesting results obtained allow at a later stage to make a prototype validating the theoretical results with experimental measures.
 Index Terms—Silica gel, Solar Cooling, Building

Experimental investigation of a novel multi-tank thermal energy storage system for solar-powered air conditioning

The volume of hot storage tank in sensible thermal energy storage (STES), integrated with solar-powered air conditioning to mitigate the misalignment between supply and demand, is too big which results in great thermal inertia. In this paper, a novel multi-tank thermal energy storage (TES) system for solar-power air conditioning, with the advantages of quick temperature rising and outstanding ability to fit variable weather, was proposed to mitigate the contradictions between demand and supply. In order to investigate effect of the number of tanks (NT) on system response time (SRT), total energy grade of water in tanks and temperature variations in charging and discharging periods, a series of experiments of TESs with different number of tanks (total volume of tanks is constant) were conducted under the same solar radiation conditions. Results show that the energy grade of water in tanks is improved through dividing thermal energy storage system into several tanks with different priorities of charging and discharging, and SRT decreases by 6.95h in four-tank TES, compared with one-tank TES. Furthermore, the duration time of ideal heating inlet water temperature (IHIWT) in entire operational period increases slowly with the number of tanks, because NT has opposite effects on duration time of IHIWT in charging and discharging periods. An optimized control strategy that tanks stored heat successively in charging period and released heat simultaneously in discharging period was proposed. It is notable that the duration time of IHIWT in four-tank TES increases 2.59h, about 26.67%, after the optimized control strategy is adopted. Therefore, the optimized TES makes the single-effect absorption chiller run at a high COP over a long time without strong variations of COP, compared with other TESs.