The impact of evaporation from porous tile on roof thermal performance: A case study of Guangzhou’s climatic conditions

Zhang, Lei; Zhang, Rongpeng; Zhang, Yu; Hong, Tianzhen; Meng, Qinglin; Feng, Yanshan

doi:10.1016/j.enbuild.2016.12.012

Cited by 22 publications

(7 citation statements)

References 35 publications

(56 reference statements)

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“…There are other roofing methods which can provide passive cooling/heating and some of these methods have a similar features to the reviewed methods. As an example, for porous roof tiles, which absorb water from rainfalls or other sources, the same principles of water evaporation will lead to heat reduction under this roofing method [82]. This method can reduce the external surface temperature by up to 11.3 • C in a subtropical climate [82], and in another experiment the temperature can be decreased 6.4 • C and 3.2 • C, for external and internal roof surfaces respectively.…”

Section: Other Roofing Methodsmentioning

confidence: 99%

A Review of Roofing Methods: Construction Features, Heat Reduction, Payback Period and Climatic Responsiveness

Abuseif

Gou

2018

Energies

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The roofs of buildings play an essential role in energy efficiency because a significant amount of solar radiation is absorbed by roofs in hot weather and a significant amount of heat is lost through roofs in cold weather. This paper is a systematic literature review about roofing methods for flat roofs. Ten roofing methods are reviewed in this paper. They are concrete roof, cool roof, insulated roof, roof garden, photovoltaic panels’ roof, biosolar roof, double-skin roof, roof ponds, skylight roof, and wind catcher. The review covers each roof’s main features, heat flux reductions, payback periods, and the appropriate climate for its implementation. Furthermore, the basic principles for selecting appropriate roofing methods are discussed and future studies for integrating these roofing methods are suggested. Some of these methods can eliminate the need of installing HVAC (Heating Ventilation and Air-conditioning) systems and others can achieve a high percentage of heat reduction if they are the right choice and they are implemented in the right circumstances. An incorrect selection could result in mild to severe energy penalties. The review contributes to the increasing knowledge about sustainable roofing and helps designers to increase building energy efficiency by selecting the appropriate roofing method.

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Section: Other Roofing Methodsmentioning

confidence: 99%

A Review of Roofing Methods: Construction Features, Heat Reduction, Payback Period and Climatic Responsiveness

Abuseif

Gou

2018

Energies

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“…In a research conducted on porous tiles in Guangzhou China, it is noted that the thermal performance of the roof is influenced by moisture content in the porous tiles. The surface temperature of the roof can be decreased up to 11.3 °C if porous tiles contain a sufficient amount of water [24]. In the case of the green roof, there is …”

Section: Literature Review On the Green Roofmentioning

confidence: 99%

Impact of Green Roof and Orientation on the Energy Performance of Buildings: A Case Study from Saudi Arabia

Khan¹,

Asif²

2017

Sustainability

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Saudi Arabia is one of the largest countries in the Middle East region in terms of population, geographic area and scale of economy. It has a fast growing energy sector with over 76% of the total electricity being consumed in the building sector. Domestic buildings account for 51% of total electricity consumption. Predominantly due to hot climatic conditions, most of the energy consumption in buildings is attributed to the heating, ventilation and air conditioning (HVAC) loads. In terms of supply mix, the country entirely relies on oil and gas to meet its energy requirements. The high growth in energy demand is imposing stringent energy, environmental and economic challenges for Saudi Arabia. The present work aims to explore prospects of energy saving in buildings through the application of green roof technology. With the help of ECOTECT modelling, the work examines the effectiveness of green roof on considering modern faculty homes built in the King Fahd University of Petroleum and Minerals situated in the hot-humid climatic conditions of the Easter Province of the country. The same building has also been investigated for the hot-dry climate of Riyadh, the capital city. The work also examines the impact of orientations on the energy performance of buildings.

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“…A porous tile was selected as the water-storage medium for the present study because it is commonly used to decorate the exterior surface of building envelopes (roofs and walls), and its evaporative cooling performance has also been previously demonstrated [10,21,22]. The considered tile was 240 mm long, 50 mm wide, and 10 mm thick, and had a mass saturated water content of 11.80% [23].…”

Section: Water-storage Mediummentioning

confidence: 99%

“…2491 (6) Evaporation from the porous tiles is mainly by vapor movement from a high vapor pressure region to a low vapor pressure region [31]. An analysis of the process involves a mathematically rigorous and complex convergence procedure, which makes the calculation of the evaporation rate complex [21]. To address this issue, based on the measured evaporation rate, Zhang et al developed a multivariate nonlinear model for predicting the evaporation rate of the porous tile [21].…”

Section: Evaporative Cooling Modulementioning

confidence: 99%

“…An analysis of the process involves a mathematically rigorous and complex convergence procedure, which makes the calculation of the evaporation rate complex [21]. To address this issue, based on the measured evaporation rate, Zhang et al developed a multivariate nonlinear model for predicting the evaporation rate of the porous tile [21]. The model, which is presented as equation (7), was used in the present study to calculate the evaporation rate and the corresponding latent heat transfer from the porous tiles.…”

Section: Evaporative Cooling Modulementioning

confidence: 99%

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Impact of post-rainfall evaporation from porous roof tiles on building cooling load in subtropical China

Zhang

Hong

et al. 2018

Applied Thermal Engineering

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Abstract:Rainfall occurs frequently in subtropical regions of China, with the subsequent water evaporation from building roofs impacting the thermal performance and the energy consumption of buildings. We proposed a novel simulation method using actual meteorological data to evaluate the impact of post-rainfall evaporation from porous roof tiles on building cooling load. New features were developed in EnegryPlus to enable the simulation: (1) an evaporation latent heat flux source term was added to the heat balance equation of the external surface, and (2) algorithms for the evaporative cooling module (ECM) were developed and implemented into EnergyPlus using the EnergyPlus Runtime Language (Erl). The ECM was validated using experimental data and there was good agreement between the simulated and experimental result. Then the ECM was used to assess the impact of evaporation from porous roof tiles on the cooling load of a one-floor building in subtropical China. The results show that the evaporation process decreased the maximal values of the external and internal roof surface temperatures by up to 6.4 °C and 3.2 °C, respectively, while the lower internal surface temperature decreased the room accumulated cooling load by up to 14.8% during the hot summer period. The enhanced EnergyPlus capability can be used to evaluate the evaporative cooling performance of roofs with water-storage mediums, as well as to quantify their impact on building cooling loads. Keywords:Rainfall event; Evaporative cooling; EnergyPlus; Building energy simulation; Cooling load; Subtropical China 2 IntroductionThe subtropical areas of China are characterized by a monsoon climate, with the precipitation between May and October accounting for approximately 85% of the annual precipitation [1]. In addition, this period of frequent rainfall coincides with that of high temperatures [2]. This climatic feature facilitates evaporative cooling through the phase change of rainwater received in porous building materials and other specially designed structures. The consequence is a significant reduction of the external surface temperature of building envelopes [3][4][5], decreased heat flow into buildings [6][7][8], and lower cooling energy demands [9][10][11]. However, existing building energy simulation platforms such as EnergyPlus do not consider this evaporative cooling effect in heat gain calculations for building envelopes in areas of frequent rainfall [12].Although several studies have been conducted to investigate the effect of rainfall on building envelopes, they mainly focused on moisture content and transport, and their effects on the building's performance and durability [13][14][15]. Moreover, most of the pioneering studies in the field were conducted in cold or temperate areas, where the buildings are exposed to alternating cold and hot seasons, and the combination of rainfall loads and cold temperatures constitute a huge challenge to building materials and construction systems [16][17][18]. It is obvious that this condition is dissimilar f...

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The impact of evaporation from porous tile on roof thermal performance: A case study of Guangzhou’s climatic conditions

Cited by 22 publications

References 35 publications

A Review of Roofing Methods: Construction Features, Heat Reduction, Payback Period and Climatic Responsiveness

A Review of Roofing Methods: Construction Features, Heat Reduction, Payback Period and Climatic Responsiveness

Impact of Green Roof and Orientation on the Energy Performance of Buildings: A Case Study from Saudi Arabia

Impact of post-rainfall evaporation from porous roof tiles on building cooling load in subtropical China

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