Vegetation insulation screen as a passive cooling system in hot humid climate: heat and mass exchanges

Abstract This study investigates the cooling performance of a passive cooling system for electric motor cooling applications. The metal-based phase change materials are used for cooling the motor and preventing its temperature rise. As compared to oil-based phase change materials, these materials have a higher melting point and thermal conductivity. The flow field and transient heat conduction are simulated using the finite volume method. The accuracy of numerical values obtained from the simulation of the phase change materials is validated. The sensitivity of the numerical results to the number of computational elements and time step value is assessed. The main goal of adopting the phase change material based passive cooling system is to maintain the operational motor temperature in the allowed range for applications with high and repetitive peak power demands such as electric vehicles by using phase change materials in cooling channels twisted around the motor. Moreover, this study investigates the effect of the phase change material container arrangement on the cooling performance of the under study cooling system.

Download Full-text

Modeling a Passive Cooling System for Photovoltaic Cells Under Concentration

ASME/JSME 2007 Thermal Engineering Heat Transfer Summer Conference, Volume 2 ◽

10.1115/ht2007-32693 ◽

2007 ◽

Cited By ~ 9

Author(s):

Allison Gray ◽

Robert Boehm ◽

Kenneth W. Stone

Keyword(s):

Solar Irradiance ◽

Waste Heat ◽

Cooling System ◽

Photovoltaic Cells ◽

Theoretical Data ◽

Photovoltaic System ◽

Passive Cooling ◽

Cell Temperature ◽

Worst Case ◽

Passive Cooling System

Cooling of photovoltaic cells under high intensity solar irradiance is a major concern when designing concentrating photovoltaic systems. The cell temperature will increase if the waste heat is not removed and the cell voltage/power will decrease with increasing cell temperature. This paper presents an analysis of the passive cooling system on the Amonix high concentration photovoltaic system (HCPV). The concentrator geometry is described. A model of the HCPV passive cooling system was made using Gambit. Assumptions are discussed that were made to create the numerical model based on the actual system, the methods for drawing the model is discussed, and images of the model are shown. Fluent was used to compute the numerical results. In addition to the theoretical results that were computed, measurements were made on a system in the field. These data are compared to the theoretical data and differences are calculated. Theoretical conditions that were studied included uniform cell temperatures and worst case weather scenarios, i.e., no wind, high ambient conditions, and high solar irradiance. The performance of the Amonix high concentrating system could be improved if more waste heat were removed from the cell. Now that a theoretical model has been developed and verified, it will be used to investigate different designs and material for increasing the cooling of the system.

Download Full-text

Performance evaluation of sub ground passive cooling system with Ecotech software simulation (Case study: Pasio Christi Church at Cibunut, Kuningan, West Java)

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/878/1/012006 ◽

2021 ◽

Vol 878 (1) ◽

pp. 012006

Author(s):

I Musdinar ◽

R A Ardli

Keyword(s):

Performance Evaluation ◽

Cooling System ◽

Passive Cooling ◽

West Java ◽

Tropical Regions ◽

Software Simulation ◽

Church Building ◽

The Difference ◽

Passive Cooling System ◽

The Church

Abstract The church in Cibunut, Kuningan, West Java has implemented a sub ground passive cooling system in its renovated building in 2018. This sub ground passive cooling system has not been widely applied in tropical regions, however the church is trying to implement it. This system is supported by making air wells and flowing cold air through distribution pipes into the room. Because not many people have implemented this system, performance evaluation through an ecotect software simulation is used to determine the success of the system in cooling the room. The research was carried out with the following steps: (i) Data collection in the form of CAD drawings of Cibunut Church building, (ii) Simulation using ecotect software, and (iii) Analysis of simulation results with thermal comfort standards in the tropics. The results of this study are conclusions from the results of simulations and analyzes, as an illustration in applying of the sub ground passive cooling system. This research helps illustrate the difference between buildings that have not applied sub ground passive cooling and buildings that have applied sub ground passive cooling.

Download Full-text

Active cooling photovoltaic with IoT facility

International Journal of Power Electronics and Drive Systems (IJPEDS) ◽

10.11591/ijpeds.v12.i3.pp1494-1504 ◽

2021 ◽

Vol 12 (3) ◽

pp. 1494

Author(s):

Muhammad Nizam Kamarudin ◽

Sahazati Md. Rozali ◽

Mohd Saifuzam Jamri

Keyword(s):

Real Time ◽

Cooling System ◽

Solar Panel ◽

State Of Charge ◽

Photovoltaic System ◽

Passive Cooling ◽

Active Cooling ◽

Passive Cooling System ◽

Pv Power Generation ◽

Sunlight Intensity

Harvesting energy from the sun makes the photovoltaic (PV) power generation a promising technology. To obtain a consistent state of charge (SOC), consistent energy must be harvested and efficiently directed to the battery. Overcharging or undercharging phenomena decreases the lifetime of the battery. Besides, the effect of irradiance toward solar in term of sunlight intensity effects the efficiency and hence, sluggish the SOC. The main problem of the solar panel revealed when the temperature has increased, the efficiency of solar panel will also be decreased. This manuscript reports the finding of developing an automatic active cooling system for a solar panel with a real time energy monitoring system with internet-of-things (IoT) facility. The IoT technology assists user to measure the efficiency of the solar panel and SOC of the battery in real time from any locations. The automatic active cooling system is designed to improve the efficiency of the solar panel. The effectiveness of the proposed system is proven via the analysis of the effect of active cooling toward efficiency and SOC of photovoltaic system. The results also tabulate the comparative studies of active-to-passive cooling system, as well as the effect of cooling towards SOC and efficiency of the solar panel.

Download Full-text

VEGETATION INSULATION SCREEN AS A PASSIVE COOLING SYSTEM IN HOT HUMID CLIMATE: HEAT AND MASS EXCHANGES

International Journal of Advanced Research ◽

10.21474/ijar01/13693 ◽

2021 ◽

Vol 9 (10) ◽

pp. 1368-1378

Author(s):

Hodo-Abalo Samah ◽

◽

Magolmeena Banna ◽

Belkacem Zeghmati ◽

◽

...

Keyword(s):

Leaf Area Index ◽

Leaf Area ◽

Cooling System ◽

Gain Factor ◽

Passive Cooling ◽

Humid Climate ◽

Heat Gain ◽

Area Index ◽

Solar Heat ◽

Solar Heat Gain

Planted roofs are passive cooling techniques that reduce the thermal load of buildings. In this paper, a Dynamic mathematical model based ontime average Navier-Stokes equationsfor a plantedroof in hothumidclimates has beendeveloped for evaluating the cooling potential.Transfer equations are solved using a finite difference scheme and Thomas algorithm. The model was applied for the simulation of a planted roof in Togolese climate conditions. Results showed that, evapotranspiration and Solar Heat gain Factor are functions of the Leaf Area Index LAI which is the most important parameter when considering the foliage material. For LAI equal to 6, latent heat peak value reaches 900 W.m-2while that of sensible heat is around 350 W.m-2. Solar heat gain factor can bereducedto 15% fortheplantedroofagainst 45% forbareroof. It is clearly proved that the foliage density and hence the vegetation canopy type selection greatly influence the thermal efficiency of the bioclimatic insulation screen. A larger Leaf Area Index reduces the solar flux penetration and increases evapotranspiration which is an important parameter when considering surrounding microclimate formation.

Download Full-text

Design of passive cooling system for a building in composite climatic conditions in India

International Journal of Sustainable Design ◽

10.1504/ijsdes.2008.017060 ◽

2008 ◽

Vol 1 (1) ◽

pp. 110 ◽

Cited By ~ 1

Author(s):

Jyotirmay Mathur ◽

Rajeev Kathpalia

Keyword(s):

Cooling System ◽

Climatic Conditions ◽

Passive Cooling ◽

Passive Cooling System

Download Full-text

Flex House

ASME 2011 5th International Conference on Energy Sustainability, Parts A, B, and C ◽

10.1115/es2011-54549 ◽

2011 ◽

Author(s):

Stanley Russell ◽

Mark Weston ◽

Yogi Goswami ◽

Matthew Doll

Keyword(s):

Closed System ◽

State Of The Art ◽

Building Envelope ◽

Passive Cooling ◽

Optimum Level ◽

Seasonal Temperature ◽

Zero Energy ◽

Humid Climate ◽

Heat Gain ◽

Hot Humid Climate

Flex House is a flexible, modular, pre-fabricated zero energy building that can be mass produced and adapted easily to a variety of site conditions and plan configurations. The key factor shaping the design is central Florida’s hot humid climate and intense solar radiation. Flex house combines the wisdom of vernacular Florida houses with state of the art Zero Energy House technologies (ZEH.) A combined system of photovoltaic panels and solar thermal concentrating panels take advantage of the region’s abundant insolation in providing clean renewable energy for the house. Conservation is achieved with state of the art mechanical systems and innovative liquid desiccant dehumidification technology along with highly efficient lighting and appliances. The hybrid nature of the Flex house allows for both an open and closed system to take advantage of the seasonal temperature variation. Central Florida buildings can conserve energy by allowing natural ventilation to take advantage of passive cooling in the mild months of the year and use a closed system to utilize mechanical cooling when temperatures are too high for passive cooling strategies. The building envelope works equally well throughout the year combining an optimum level of insulation, resistance to air infiltration, transparency for daylight, and flexibility that allows for opening and closing of the house. Flex House is designed with a strong connection between interior spaces and the outdoors with carefully placed fenestration and a movable wall system which enables the house to transform in response to the temperature variations throughout the year. The house also addresses the massive heat gain that occurs through the roof, which can generate temperatures in excess of 140 degrees. Flex House incorporates a parasol-like outer structure that shades the roof, walls and courtyard minimizing heat gain through the building envelope. To be implemented on a large scale, ZEH must be affordable for people earning a moderate income. Site built construction is time consuming and wasteful and results in higher costs. Building homes in a controlled environment can reduce material waste, and construction costs while increasing efficiency. Pre-fabricating Flex House minimizes preparation time, waste and safety concerns and maximizes economy, quality control, efficiency and safety during the construction process. This paper is an account of the design and construction of Flex House, a ZEH for central Florida’s hot humid climate.

Download Full-text