Validation of periodic solution for computing CLTD (cooling load temperature difference) values for building walls and flat roofs

Zainal, Omer A.; Yumrutaş, Recep

doi:10.1016/j.energy.2015.01.088

Cited by 26 publications

(13 citation statements)

References 10 publications

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“…a transient solution. Zainal and Yumrutas [6] used the CFFT technique to find the CLTD values numerically for multilayered roofs and walls. A one-dimensional solution to the transient problem is a new approach to estimate CLTD values.…”

Section: Methodsmentioning

confidence: 99%

Comparison of Thermal Performance of Newly Produced Lightweight Wall and Roof Elements for Energy-efficient Buildings

Oktay

Yumrutaş

Argunhan

2020

Hittite J. Sci. Eng.

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T he building sector is responsible for the enormous amount of total energy consumption in the World. Most of this energy is used for the provision of heating and cooling applications. The main objective of a cooling or heating system is to maintain the thermal comfort conditions to the occupants of the building that are required for indoor products and processes. The heat ratio that must be removed from a room to maintain a stable temperature at the comfort level is defined as a cooling load [1]. The heat gain through the building envelope, which includes roofs and walls in most buildings, constitutes a significant partition of the overall cooling load of space due to its large area [2]. If the structures having appropriate thermal properties are selected, also accurate cooling load calculation is performed, and then suitable HVAC system components can be selected. Therefore, estimation of the cooling load through the building envelope is an essential task in the selection of proper components of an HVAC system that influences the building's performance. However, an accurate calculation of the cooling load is quite complicated

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Section: Methodsmentioning

confidence: 99%

Comparison of Thermal Performance of Newly Produced Lightweight Wall and Roof Elements for Energy-efficient Buildings

Oktay

Yumrutaş

Argunhan

2020

Hittite J. Sci. Eng.

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“…where I b , I d and I represent beam, diffuse and total radiation on horizontal surface, respectively (kW/m 2 ); ρ g is the ground reflectance and is taken as 0.2 in the present study [39]; R b is geometric factor which is defined as the ratio of beam radiation on a tilted surface to that on a horizontal surface, which is expressed as…”

Section: Components Modelling 221 Building Modelmentioning

confidence: 99%

Scheduling distributed energy resources and smart buildings of a microgrid via multi‐time scale and model predictive control method

Jin

Jiang

et al. 2018

IET Renewable Power Generation

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Zening 2019. Scheduling distributed energy resources and smart buildings of a microgrid via multi-time scale and model predictive control method. IET Renewable Power Generation 13 (6) , pp.Abstract: To schedule the distributed energy resources (DERs) and smart buildings of a Microgrid in an optimal way and consider the uncertainties associated to forecasting data, a two-stage scheduling framework is proposed in this paper. In stage I, a day-ahead dynamic optimal economic scheduling method is proposed to minimise the daily operating cost of the Microgrid. In stage II, a model predictive control based intra-hour adjustment method is proposed to reschedule the DERs and smart buildings to cope with the uncertainties. A virtual energy storage system is modelled and scheduled as a flexible unit using the inertia of building in both stages. The underlying electric network and the associated power flow and system operational constraints of the Microgrid are considered in the proposed scheduling method. Numerical studies demonstrate that the proposed method can reduce the daily operating cost in stage I and smooth the fluctuations of the electric tie-line power of the Microgrid caused by the day-ahead forecasting errors in stage II. Meanwhile, the fluctuations of the electric tieline power with the MPC based strategy are better smoothed compared with the traditional open-loop and single-period based optimisation methods, which demonstrates better performance of the proposed scheduling method in a time-varying context.

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“…However, past studies only took into account the first two items on the right side of Eq. (6a) [28,29], which may overestimate the sol-air temperature with evaporation on the exterior roof surface. Thus, in this study, the sol-air temperature variation due to evaporation was considered as the third item in Eq.…”

Section: Appendix Amentioning

confidence: 99%

“…In their discussion of the surface heat balance equation, most previous studies have only considered the solar radiation term and the combined convection and radiation heat transfer term [28,29]. In this study, the evaporative latent heat flux, which was calculated using the statistical model in Subsection 2.1, was taken into account.…”

Section: One-dimensional Unsteady Heat Transfer Of Roofsmentioning

confidence: 99%

See 1 more Smart Citation

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

Zhang

et al. 2017

Energy and Buildings

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a b s t r a c tThe evaporative-cooling roof is a popular passive energy conservation technique. This article presents a novel approach for modelling and analysing the influence of evaporation on roof thermal performance. A multivariate nonlinear model was developed for the prediction of the evaporation rate from porous tile. A computer program was then developed based on the one-dimensional roof unsteady heat transfer theory. Finally, the computer program and hourly weather data of Guangzhou, China, were used to analyse the impacts of evaporation (including the evaporation start time and water-application frequency) and slope orientation on roof thermal performance. Evaporation beginning at 11:00 can reduce the external surface temperatures of a horizontal roof and 30 • -inclined east-sloping and west-sloping roofs by up to 11.3, 10.7, and 9.8 • C, respectively, from those of a non-evaporative roof. This, in turn, can reduce the peak-hour (16:00-20:00) internal surface heat flux. Additionally, with the horizontal roof, the reduction in the peak-hour heat flux can be doubled if the evaporative layer is frequently replenished with water.

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Validation of periodic solution for computing CLTD (cooling load temperature difference) values for building walls and flat roofs

Cited by 26 publications

References 10 publications

Comparison of Thermal Performance of Newly Produced Lightweight Wall and Roof Elements for Energy-efficient Buildings

Comparison of Thermal Performance of Newly Produced Lightweight Wall and Roof Elements for Energy-efficient Buildings

Scheduling distributed energy resources and smart buildings of a microgrid via multi‐time scale and model predictive control method

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

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