scholarly journals Effect of Turf Roof Slabs on Indoor Thermal Performance in Tropical Climates: A Life Cycle Cost Approach

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
R. U. Halwatura
Keyword(s):  
Life Cycle ◽  
Life Cycle Cost ◽  
Air Conditioning ◽  
Green Roof ◽  
Green Roofs ◽  
Scale Model ◽  
Small Scale ◽  
Indoor Temperature ◽  
Scale Models ◽  
Different Types

Urbanization related to population growth is one of the burning issues that the world is facing today. Parallel to this, there is visible evidence of a possible energy crisis in the near future. Thus, scientists have paid attention to sustainable development methods, and in the field of building construction also, several innovations have been proposed. For example, green roof concept is one of such which is considered a viable method mainly to reduce urban heat island effect, to regain lost land spaces in cities, and to increase aesthetics in cities. The present study was aimed at investigating the impact of green roofs on indoor temperature of buildings, the effect of different types of roofs on the air conditioning loads, and the life cycle cost of buildings with different types of roofing. The study was conducted in several phases: initial small-scale models to determine the heat flow characteristics of roof top soil layers with different thicknesses, a large-scale model applying the findings of the small-scale models to determine temperature fluctuations within a building with other common roofing systems, a computer simulation to investigate air conditioning loads in a typical building with cement fiber sheets and green roof slabs, a comparative analysis of the effect of traditional type roofs and green roofs on the air conditioning loads, and finally an analysis to predict the influence of traditional type roofs and green roofs on life cycle cost of the buildings. The main findings of the study were that green roofs are able to reduce the indoor temperature of buildings and are able to achieve better heat transfer through the roof, and, thus a lower cooling load is necessary for air conditioning and has the possibility of reducing life cycle cost of a building.

scholarly journals Roughness Lengths for Momentum and Heat Derived from Outdoor Urban Scale Models

2007 ◽  
Vol 46 (7) ◽  
pp. 1067-1079 ◽  
Author(s):  
M. Kanda ◽  
M. Kanega ◽  
T. Kawai ◽  
R. Moriwaki ◽  
H. Sugawara
Keyword(s):  
Wind Direction ◽  
Roughness Length ◽  
Scale Dependence ◽  
Scale Model ◽  
Small Scale ◽  
Physical Scale ◽  
Scale Models ◽  
Roughness Lengths ◽  
Urban Sites ◽  
Obstacle Height

Abstract Urban climate experimental results from the Comprehensive Outdoor Scale Model (COSMO) were used to estimate roughness lengths for momentum and heat. Two different physical scale models were used to investigate the scale dependence of the roughness lengths; the large scale model included an aligned array of 1.5-m concrete cubes, and the small scale model had a geometrically similar array of 0.15-m concrete cubes. Only turbulent data from the unstable boundary layers were considered. The roughness length for momentum relative to the obstacle height was dependent on wind direction, but the scale dependence was not evident. Estimated values agreed well with a conventional morphometric relationship. The logarithm of the roughness length for heat relative to the obstacle height depended on the scale but was insensitive to wind direction. COSMO data were used successfully to regress a theoretical relationship between κB−1, the logarithmic ratio of roughness length for momentum to heat, and Re*, the roughness Reynolds number. Values of κB−1 associated with Re* for three different urban sites from previous field experiments were intercompared. A surprising finding was that, even though surface geometry differed from site to site, the regressed function agreed with data from the three urban sites as well as with the COSMO data. Field data showed that κB−1 values decreased as the areal fraction of vegetation increased. The observed dependency of the bulk transfer coefficient on atmospheric stability in the COSMO data could be reproduced using the regressed function of Re* and κB−1, together with a Monin–Obukhov similarity framework.

Designing and Installing a Retrofit Heated Green Roof Using Either Co-Gen Waste Hot Water or Municipal Waste Steam Heat as Energy Source

2014 ◽  
Author(s):  
Robert Dell ◽  
C. S. Wei ◽  
Raj Parikh ◽  
Runar Unnthorsson ◽  
William Foley
Keyword(s):  
New York ◽  
New York City ◽  
York City ◽  
Waste Heat ◽  
Green Roof ◽  
Cooling Water ◽  
District Heating ◽  
Green Roofs ◽  
Hot Water ◽  
Small Scale

Municipal District Heating Services and Combined Heat and Power (CHP) systems can produce waste heat in the form of steam condensate and hot water. The authors have developed a system to use this thermal pollution to heat the soil and growth medium of green roofs and outdoor gardens. The system enables plant life to survive colder climates and increases growth often in excess of 20% (Power2013-98172). In New York City test heated green roofs, the system can save vast amounts of normally required cooling water that is tapped from the overburdened municipal supply (IMECE2013-65200). Existing small scale green roofs in New York City and larger scale heated green roof retrofit in New York City is presented to indicate additional construction details, thermal considerations, and potential code compliance considerations.

Analyze the energy balance and energy-saving benefits of  green roofs

2021 ◽  
Author(s):  
Chuan Ching Pang
Keyword(s):  
Energy Balance ◽  
Energy Saving ◽  
Green Roof ◽  
Green Roofs ◽  
Radiant Heat ◽  
Building Energy ◽  
Control Group ◽  
Indoor Temperature ◽  
The Impact ◽  
Experimental Group

<p>In the context of rapid global urbanization, problems such as urban thermal effects often occur, which may cause the increase in building energy consumption. Green roofs have the effect to regulating the indoor temperature of buildings. This study is expected to evaluate the cooling and energy-saving benefits of green roofs and build an experimental to simulation buildings situation , the control group without green roof and the experimental group with green roof, compare the indoor temperature and heat flux changes in the control group and the experimental group, and calculate the radiant heat, latent heat, sensible heat, conduction heat in the green roof layer , And build a model to simulation energy project to discuss the energy balance of the green roof and the impact on the energy of the buildings below, and analyze the cooling and energy saving effects of the green roof.</p>

COMPARISON OF LIFE CYCLE COST OF CENTRALIZED AND SPLIT AIR CONDITIONING SYSTEMS

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Dharma Hagare ◽  
Jason Ho ◽  
Swapan Saha
Keyword(s):  
Life Cycle ◽  
Life Cycle Analysis ◽  
Life Cycle Cost ◽  
Air Conditioning ◽  
Residential Buildings ◽  
Operating Conditions ◽  
Central System ◽  
Operating Schedule ◽  
Ac Systems ◽  
Split System

Central and split systems are the two most common air conditioning (AC) systems used in residential applications. Central system employs one large unit to produce and distribute conditioned air through a system of ductwork. On the other hand, the split system, employs several small ACs. Each AC consisted of outdoor and indoor units to produce conditioned air directly to the designed area. Each system has distinct strengths and weaknesses. Depending on the structure of cooling area and operating schedule, the performance of each system will be different. The aim of this paper is to examine the impact of various parameters such as operating schedule and building characteristics to the performance of central and split AC systems over the 25 years of their operation. The life cycle analysis (LCA) considered essential factors which have significant impact on the energy consumption and both initial and operating costs of the two systems. All required sections of life cycle analysis are included according to the relevant Australian Standards. The results indicated that under standard operating conditions, central system is more economical and energy efficient than split system. However, when the flexibility in operation of split system is considered, there was a significant reduction in its operating cost, which was below that of central system. Overall, total life cycle cost of split system was slightly lower than central system. Also, considering the usage flexibility and the comfort of users, it appears that the split system is more suitable than the central AC system for residential buildings.

scholarly journals Life Cycle Cost Comparison Study of PV and Concrete Rooftop in Jakarta

2018 ◽  
Vol 2018 ◽  
pp. 1-5 ◽  
Author(s):  
Religiana Hendarti
Keyword(s):  
Life Cycle ◽  
Life Cycle Cost ◽  
Department Of Energy ◽  
Cost Comparison ◽  
Electricity Production ◽  
Solar Panels ◽  
The Us ◽  
Different Types ◽  
Building Life Cycle ◽  
Total Life

This paper presents a comparative study of “life cycle cost” or LCC of a building school rooftop element in Jakarta. The simulation applied two different types of roof: a concrete roof and a PV rooftop. The aim of this study is to investigate the electricity production of the solar panels, the saving to investment ratio or SIR, and the total life cycle cost of each rooftop element. To accommodate those objectives, the calculation utilized a software called “Building Life Cycle Cost (BLCC) version 5” which is a product of the US Department of Energy. The simulation results showed that the LCC can be improved by 27.6%, and the “discounted payback” is reached at year 15. Indeed, this indicates that a roof made of solar panels is promising to replace the existing concrete roof.

Enhancing the Built Environment by Green Roofs

2010 ◽  
Vol 150-151 ◽  
pp. 267-273
Author(s):  
Jin Sheng Du ◽  
Pui Lam Ng ◽  
Jia Jian Chen ◽  
Wilson Wai Sin Fung
Keyword(s):  
Built Environment ◽  
Green Roof ◽  
Green Roofs ◽  
Materials Design ◽  
Urban Habitat ◽  
Structural Arrangement ◽  
Different Types

Green roof systems are living vegetation integrated on top of roofs. They could enhance the built environment in a number of ways. Herein, different types of green roof and their structural arrangement and materials design are introduced. Various benefits offered by green roof to the urban habitat are discussed. Finally, examples of applications of green roofs are presented.

Small-Scale Models for Testing Masonry Structures

2010 ◽  
Vol 133-134 ◽  
pp. 497-502 ◽  
Author(s):  
Alvaro Quinonez ◽  
Jennifer Zessin ◽  
Aissata Nutzel ◽  
John Ochsendorf
Keyword(s):  
Large Scale ◽  
Low Cost ◽  
Three Dimensional ◽  
Model Testing ◽  
Scale Model ◽  
Small Scale ◽  
Material Strength ◽  
Masonry Structures ◽  
Scale Models ◽  
Set Up

Experiments may be used to verify numerical and analytical results, but large-scale model testing is associated with high costs and lengthy set-up times. In contrast, small-scale model testing is inexpensive, non-invasive, and easy to replicate over several trials. This paper proposes a new method of masonry model generation using three-dimensional printing technology. Small-scale models are created as an assemblage of individual blocks representing the original structure’s geometry and stereotomy. Two model domes are tested to collapse due to outward support displacements, and experimental data from these tests is compared with analytical predictions. Results of these experiments provide a strong understanding of the mechanics of actual masonry structures and can be used to demonstrate the structural capacity of masonry structures with extensive cracking. Challenges for this work, such as imperfections in the model geometry and construction problems, are also addressed. This experimental method can provide a low-cost alternative for the collapse analysis of complex masonry structures, the safety of which depends primarily on stability rather than material strength.

Sign in / Sign up

Export Citation Format

Share Document