Yupeng Wu

Building integrated solar thermal (BIST) technologies and their applications : A review of structural design and architectural integration

Solar energy has enormous potential to meet the majority of present world energy demand by effective integration with local building components. One of the most promising technologies is building integrated solar thermal (BIST) technology. This paper presents a review of the available literature covering various types of BIST technologies and their applications in terms of structural design and architectural integration. The review covers detailed description of BIST systems using air, hydraulic (water/heat pipe/refrigerant) and phase changing materials (PCM) as the working medium. The fundamental structure of BIST and the various specific structures of available BIST in the literature are described. Design criteria and practical operation conditions of BIST systems are illustrated. The state of pilot projects is also fully depicted. Current barriers and future development opportunities are therefore concluded. Based on the thorough review, it is clear that BIST is very promising devices with considerable energy saving prospective and building integration feasibility. This review shall facilitate the development of solar driven service for buildings and help the corresponding saving in fossil fuel consumption and the reduction in carbon emission.

Crystallized TiO2 (A)–VO2 (M/R) nanocomposite films with electrochromism–thermochromism dual-response properties

Thermochromic (TC) and electrochromic (EC) smart windows are the mostly studied categories of smart window, but they usually work in different wavebands, and each have their own advantages. This work offers a method to combine the advantages of TC and EC smart windows by synthesizing TC–EC dual-response TiO2–VO2 nanocomposite films. These films were prepared by dispersing VO2 nanoparticles (NPs) in TiO2 sols and then underwent annealing. The optimized film showed a luminous transmittance (Tlum) of 66.1% at 20 °C, 59.3% at 90 °C and a ΔTsol of 11.2%. By applying a voltage of −5 V, the film showed an EC transmittance modulation (ΔT) of 19.1% at 630 nm, a combined performance of Tlum = 44.7% and ΔTsol = 17.1% (increased by 52%). The color of the films could also be modified from a yellowish brown to a light blue, which is meaningful for practical usage. The current TiO2–VO2 nanocomposite film combines TC and EC performance, which may be an important breakthrough in energy saving smart windows.

Fluorescent carbon nanoparticles for sensitive and selective detection of palladium (Pd 2

Fluorescent carbon nanoparticles (CNPs) were synthesized using well-known citric acid and polyethylenimine precursors but under a modified microwave reaction conditions in order to achieve high sensitivity and selectivity for Pd2+. The as-synthesized fluorescent CNPs with an average diameter of 2-3 nm exhibited good water solubility and photo-stability. The CNPs were systematically characterized using various advanced techniques and the fluorescence study on the as-prepared CNPs showed the excitation-dependent emission properties. Finally, the as-synthesized carbon nanoparticles served as a promising fluorescence probe for Pd2+ sensing. The sensitivity and the selectivity for Pd2+ detection were investigated by fluorescence quenching titrations and comparison of various competing metal ions, respectively. The results show that besides the excellent selectivity to Pd2+ against other metal ions, the limit of detection to Pd2+ could also reach as low as 12.4 nM, which is much lower than the threshold concentration limit of Pd2+ in medicine and environmental samples. The findings here indicate that the as-prepared CNPs hold great promise as a low-cost sensing material for sensitive and selective detection of palladium.

An initial concept design of an innovative flat-plate Solar Thermal Facade for building integration

An initial concept design of an innovative flat-plate solar thermal facade for building integration

Optical and thermal analysis of different asymmetric compound parabolic photovoltaic concentrators (ACPPVC) systems for building integration

Ray-trace techniques have been used to predict the optical performance and angular acceptance of Asymmetric Compound Parabolic Photovoltaic Concentrator (ACPPVC) systems suitable for integration into vertical south facing building facades. Untruncated and truncated ACPPVC systems ACPPVC-50, ACPPVC-55 and ACPPVC-60, which have acceptance angels of 50° and 0°, 55° and 0°, 60° and 0°, respectively, have been simulated. The PV absorber was 0.125m wide in all simulations. Comparisons of angular acceptance between the untruncated and truncated systems are also discussed. Increased truncation leads to increased angular acceptance with reduced maximum concentration. From the simulations undertake, the angular acceptance was 100% in the range of incidence angles between the acceptance half angels for all ACPPVC systems. The highest optical efficiency predicted was 88.67% for all ACPPVC systems. The predicted solar flux distributions over the PV surface for the truncated ACPPVC-55 system are presented for selected angles of incidence along with concentration ratio. The temperatures within the truncated ACPPVC-55 system predicted using Computational Fluid Dynamics are presented for various solar incidence angles.