Thermal and energy performance of a solar-driven desiccant cooling system using an internally cooled desiccant wheel in various climate conditions

2021 ◽  
Vol 185 ◽  
pp. 116077
Author(s):  
Xingchao Zhou
Keyword(s):  
Cooling System ◽  
Energy Performance ◽  
Climate Conditions ◽  
Desiccant Wheel ◽  
Internally Cooled

An alternative general method to evaluate the atmospheric down-welling radiation

2016 ◽  
Vol 38 (2) ◽  
pp. 133-150
Author(s):  
Yan Wang ◽  
Dongmei Pan ◽  
Lei Wang ◽  
Enshen Long ◽  
Shiming Deng
Keyword(s):  
Empirical Formula ◽  
Cooling System ◽  
Energy Performance ◽  
Building Roof ◽  
Climate Conditions ◽  
Roof System ◽  
Thermal Environments ◽  
Water Pond ◽  
Passive Cooling System ◽  
General Method

The importance of atmospheric down-welling radiation in studying building thermal environments and energy performance has been well identified, and empirical formulae to evaluate atmospheric down-welling radiation values developed with their inadequacies. In this paper, a study of developing an alternative general method for evaluating atmospheric down-welling radiation values to the water pond-based empirical formula by Clark and Allen is reported. The validity of the alternative general method has been demonstrated by comparing the atmospheric down-welling radiation values evaluated using the alternative general method and that using the Clark and Allen’s formula. Since the alternative general method developed is based on a building roof system, and no water is involved, the alternative general method developed in this paper appears to have more advantages. On one hand, this could eliminate any potential impacts on prediction accuracy when water is used in different climates. On the other hand, the application of the alternative general method is relatively easier as only a suitable existing roof system is required. Therefore, the use of alternative general method can provide a more reliable and economic alternative in evaluating atmospheric down-welling radiation, when compared to using Clark and Allen’s empirical formula. Practical application The alternative general method developed for evaluating atmospheric down-welling radiation values in this paper could be used as an alternative to the empirical formula proposed by Clark and Allen and is valid for all climate conditions and easy to be implemented to evaluate alternative general method values. It can be used when evaluating building night sky cooling, building passive cooling system, etc.

scholarly journals Performance Evaluation of LiBr-H2O Vapours Absorption System for an Office Building Cooling

2020 ◽  
pp. 9-21
Author(s):  
Abhishek Ajay ◽  
R. S. Gill ◽  
Rupinder Pal Singh
Keyword(s):  
Room Temperature ◽  
Cooling System ◽  
Thermodynamic Simulation ◽  
Lithium Bromide ◽  
Energy Performance ◽  
Coefficient Of Performance ◽  
Low Grade ◽  
Absorption System ◽  
Climate Conditions ◽  
Condenser Temperature

The aim of this paper is to assess the energy performance by simulation of a single effect LiBr-H2O vapour absorption system for office room cooling under Ludhiana (31°N) climate conditions. In an absorption cooling system, compressor which is using high grade energy, replaced by a combination of generator and absorber. The low grade heat is supplied to the generator which produces the cooling effect in the evaporator section. In the present work, lithium bromide is used as absorbent and water as refrigerant. A thermodynamic simulation of the cycle is carried out to investigate the effects of office room temperature and condenser temperature on the performance of the LiBr-H2O vapour absorption system. It was concluded that coefficient of performance (COP) increases from 0.55 to 0.75 as office room temperature increases from 22 to 30°C for fixed value of condenser temperature of 46°C. The maximum COP was observed when system runs on least value of condenser temperature.

scholarly journals Performance investigation of integrated PVT/adsorption cooling system under the climate conditions of Middle East

2020 ◽  
Vol 6 ◽  
pp. 168-173
Author(s):  
Ahmed A. Hassan ◽  
Ahmed E. Elwardany ◽  
Shinichi Ookawara ◽  
Ibrahim I. El-Sharkawy
Keyword(s):  
Middle East ◽  
Cooling System ◽  
Climate Conditions ◽  
Adsorption Cooling System

scholarly journals UNDERSTANDING THE EMBEDDED CARBON CHALLENGES OF BUILDING SERVICE SYSTEMS

2021 ◽  
Vol 1 ◽  
pp. 3279-3288
Author(s):  
Maria Hein ◽  
Darren Anthony Jones ◽  
Claudia Margot Eckert
Keyword(s):  
Energy Use ◽  
Cooling System ◽  
Current System ◽  
Energy Performance ◽  
Service Systems ◽  
Carbon Footprints ◽  
Embodied Carbon ◽  
Study Results ◽  
Operational Energy

AbstractEnergy consumed in buildings is a main contributor to CO2 emissions, there is therefore a need to improve the energy performance of buildings, particularly commercial buildings whereby building service systems are often substantially over-designed due to the application of excess margins during the design process.The cooling system of an NHS Hospital was studied and modelled in order to identify if the system was overdesigned, and to quantify the oversizing impact on the system operational and embodied carbon footprints. Looking at the operational energy use and environmental performance of the current system as well as an alternative optimised system through appropriate modelling and calculation, the case study results indicate significant environmental impacts are caused by the oversizing of cooling system.The study also established that it is currently more difficult to obtain an estimate of the embodied carbon footprint of building service systems. It is therefore the responsibility of the machine builders to provide information and data relating to the embodied carbon of their products, which in the longer term, this is likely to become a standard industry requirement.

scholarly journals A New Design of an Integrated Solar Absorption Cooling System Driven by an Evacuated Tube Collector: A Case Study for Baghdad, Iraq

2020 ◽  
Vol 10 (10) ◽  
pp. 3622 ◽  
Author(s):  
Adil Al-Falahi ◽  
Falah Alobaid ◽  
Bernd Epple
Keyword(s):  
Thermal Performance ◽  
Air Conditioning ◽  
Cooling System ◽  
Electrical Power ◽  
Energy Performance ◽  
Coefficient Of Performance ◽  
Solar Absorption ◽  
Air Conditioning System ◽  
Solar Fraction ◽  
Design Variables

The electrical power consumption of refrigeration equipment leads to a significant influence on the supply network, especially on the hottest days during the cooling season (and this is besides the conventional electricity problem in Iraq). The aim of this work is to investigate the energy performance of a solar-driven air-conditioning system utilizing absorption technology under climate in Baghdad, Iraq. The solar fraction and the thermal performance of the solar air-conditioning system were analyzed for various months in the cooling season. It was found that the system operating in August shows the best monthly average solar fraction (of 59.4%) and coefficient of performance (COP) (of 0.52) due to the high solar potential in this month. Moreover, the seasonal integrated collector efficiency was 54%, providing a seasonal solar fraction of 58%, and the COP of the absorption chiller was 0.44, which was in limit, as reported in the literature for similar systems. A detailed parametric analysis was carried out to evaluate the thermal performance of the system and analyses, and the effect of design variables on the solar fraction of the system during the cooling season.

scholarly journals Economic aspects and energy performance of the cooled polycrystalline solar photovoltaic technology

2016 ◽  
Vol 5 (1-2) ◽  
pp. 162-170
Author(s):  
Henrik Zsiborács ◽  
Béla Pályi ◽  
Gábor Pintér ◽  
Nóra Hegedűsné Baranyai ◽  
Péter Szabó ◽  
...  
Keyword(s):  
Cooling System ◽  
Energy Performance ◽  
Climatic Conditions ◽  
Green Energy ◽  
Effect Of Temperature ◽  
Economic Aspects ◽  
Solar Pv ◽  
Pv System ◽  
Economic Relations ◽  
Cooling Technology

In this paper the economic aspects of the water spraying cooling technology of polycrystalline solar modules with respect to the effect of temperature on performance was examined. The main purpose of this work was to explore the economic relations of the spraying cooling technology of solar modules. In the study 5 kW PV system for residential customers, 5 kW and 50 kW PV system for business customer were studied. In Hungarian climatic conditions, considering the inflation values used, the interest rate, the annual utilization of the cooling system, the expected profit and the maintenance costs show us that neither of the cooling solutions is capable of better payback time than the reference uncooled solar PV system. The further research goal is to determine the usability of the cooling system in such countries which have on the one hand more ideal climatic conditions, on the other hand more predictable green energy feed regulations.

scholarly journals Cool Roof Impact on Building Energy Need: The Role of Thermal Insulation with Varying Climate Conditions

Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3354 ◽  
Author(s):  
Piselli ◽  
Pisello ◽  
Saffari ◽  
Gracia ◽  
Cotana ◽  
...  
Keyword(s):  
Thermal Insulation ◽  
Thermal Energy ◽  
Building Energy ◽  
Energy Performance ◽  
Cold Climate ◽  
Climate Conditions ◽  
Building Energy Performance ◽  
Cool Roof ◽  
Solar Reflectance

Cool roof effectiveness in improving building thermal-energy performance is affected by different variables. In particular, roof insulation level and climate conditions are key parameters influencing cool roofs benefits and whole building energy performance. This work aims at assessing the role of cool roof in the optimum roof configuration, i.e., combination of solar reflectance capability and thermal insulation level, in terms of building energy performance in different climate conditions worldwide. To this aim, coupled dynamic thermal-energy simulation and optimization analysis is carried out. In detail, multi-dimensional optimization of combined building roof thermal insulation and solar reflectance is developed to minimize building annual energy consumption for heating–cooling. Results highlight how a high reflectance roof minimizes annual energy need for a small standard office building in the majority of considered climates. Moreover, building energy performance is more sensitive to roof solar reflectance than thermal insulation level, except for the coldest conditions. Therefore, for the selected building, the optimum roof typology presents high solar reflectance capability (0.8) and no/low insulation level (0.00–0.03 m), except for extremely hot or cold climate zones. Accordingly, this research shows how the classic approach of super-insulated buildings should be reframed for the office case toward truly environmentally friendly buildings.

scholarly journals Energy Conservation Potential of Economizer Controls Using Optimal Outdoor Air Fraction Based on Field Study

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5038
Author(s):  
Goopyo Hong ◽  
Chul Kim ◽  
Jun Hong
Keyword(s):  
Energy Consumption ◽  
Energy Conservation ◽  
Temperature Control ◽  
Energy Savings ◽  
Cooling System ◽  
Energy Performance ◽  
Outdoor Air ◽  
Humid Climate ◽  
Differential Enthalpy ◽  
The Impact

In commercial buildings, HVAC systems are becoming a primary driver of energy consumption, which already account for 45% of the total building energy consumption. In the previous literature, researchers have studied several energy conservation measures to reduce HVAC system energy consumption. One of the effective ways is an economizer in air-handling units. Therefore, this study quantified the impact of the outdoor air fraction by economizer control type in cooling system loads based on actual air-handling unit operation data in a hospital. The optimal outdoor air fraction and energy performance for economizer control types were calculated and analyzed. The result showed that economizer controls using optimal outdoor air fraction were up to 45% more efficient in cooling loads than existing HVAC operations in the hospital. The energy savings potential was 6–14% of the differential dry-bulb temperature control, 17–27% of the differential enthalpy control, 8–17% of the differential dry-bulb temperature and high-limit differential enthalpy control, and 16–27% of the differential enthalpy and high-limit differential dry-bulb temperature control compared to the no economizer control. The result of this study will contribute to providing a better understanding of economizer controls in the hospital when the building operates in hot-humid climate regions.

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