Mohammad Ariful Islam

Effect of external shading and window glazing on energy consumption of buildings in Bangladesh

ABSTRACT Energy efficiency of buildings is attracting significant attention from the research community as the world is moving towards sustainable buildings design. With fast increasing energy consumption attributed to residential buildings in Bangladesh, there is a need to concentrate on construction and design of building in order to improve the energy performance of buildings. This paper provides some guidelines to minimize the building energy use choosing best window glazing types of residential buildings in Bangladesh. External shading influences the solar energy on a window and the transmitted energy within the room through the window. In the present study using EnergyPlus software, advanced glazing and shading on the solar energy transmitted into or lost from the room through the fenestration areas have been evaluated for usual residential buildings in Jessore, Bangladesh. Huge reduction in the annual energy transferred into the buildings is possible with appropriate overhangs or side fins in the windows. Also, proper shaded simple glazing can have an energetic behaviour equivalent to high-performance glazing. From the results, it has been seen that choosing the best window with different glazing, overhangs and side fins based on energy evaluation is achievable.

Transport properties measurement on low GWP alternative refrigerants

New experimental data on the thermal conductivity and the viscosity of low-GWP refrigerants such as HFOs are reported in order to contribute to the development of low-GWP refrigeration/heat pump systems. Accurate data on thermodynamic and transport properties are indispensable to design and to manufacture the systems with high efficiency. However, there are only limited data on the properties. In this study, the thermal conductivity and viscosity of low-GWP refrigerants were measured by a transient hot-wire method and tandem capillary tubes method respectively with wide temperature and pressure range covered from subcooled liquid to superheated vapor region.

Application of the extended corresponding states model for prediction of the viscosity and thermal conductivity of cis-1,3,3,3-tetrafluoropropene (R1234ze(Z))

Prediction of the transport properties of low global warming potential refrigerants is a key issue for the refrigeration industry. In this work, the extended corresponding states models coupled with density-independent shape factors (empirical shape factors) or density-dependent shape factors (exact shape factors) are individually applied to predict the viscosity and thermal conductivity of 1,3,3,3-tetrafluoropropene (R1234ze(Z)). These models use 1,1,1,2-tetrafluoroethane (R134a) as a reference fluid. Empirical shape factors are obtained from the vapor pressures and saturated liquid densities of R1234ze(Z) and R134a. Exact shape factors are calculated from equations of state for these refrigerants. Predicted values with the extended corresponding states models are compared with experimental data, and the prediction capability of each model is discussed. In addition, viscosity and thermal conductivity shape factors are introduced to improve the prediction capability. With these additional shape factors, the extended corresponding states models represent the experimental data of the viscosity and thermal conductivity of R1234ze(Z) within ±2% and ±1%, respectively.