Comparative analysis of hydraulic refrigeration and mechanical vapour compression water cooling technologies in designing a technical system for oysters conservation.

The phenomenon of summer mortality in Pacific oysters cultures also occurs in Brazilian crops, with predominance in the adult phase, generating significant losses for local producers. In the search for a technological solution to mitigate its effects, the mechanical vapour compression and hydraulic refrigeration concepts are evaluated as two proposed cooling technologies. The comparative analysis carried out with numeric simulations indicated that the hydraulic cooling system presents disadvantages regarding both the size of the compression column and the energy efficiency, compared to the mechanical vapour compression cycle. By computing only the compression power, a COP value of 6.9 results for the MVCS at TCOND = 29.5 oC and TEVAP = 7.2 oC, while for HRS the COP value is around 3.1 for identical conditions. Results from the analysis contradict former publications, but are consistent with recent findings reported in literature.

Weather-based indicators for analysis of moisture risks in buildings.

Moisture is one of the main issues in building disorders. It can lead to microorganism's growth, material deterioration and impact on energy consumption. A comprehensive overview on the scale of the country considering climatic conditions may be an important starting point for potential moisture risks in building analyses. In this paper, we present a method in which weather-based indicators are developed for a first outline of the potential moisture risk in buildings considering the main climatic sources of moisture. The proposed method is related to weather parameters, comprising two new indicators - in a total of three - that are plotted in the country map using Geographic Information System to spatially represent the risk across the country territory. The method is applied for Brazil, and results indicate high weather-based moisture risks in highly densely populated areas. The case study highlights the importance of the presented methodology as a first analysis of potential moisture risk on a country scale.

Microstructural Characterization of Porous Clay-Based Ceramic Composites.

Clay-based materials are the most traditional components of buildings. To improve their performance in a sustainable way, agents can be mixed to fired clay acting as a pore-forming factor. However, firing temperatures highly influence their microstructure which is closely linked to a material's final performance as a ceramic block. To highlight the influence of the firing temperature on microstructure, and more specifically on the pore size distribution of clay-based materials, three innovative porous materials were manufactured. These materials were produced by mixing clay and pore-forming agents. They were characterized by optical and scanning electronic microscopy, x-ray diffraction, mercury intrusion and nitrogen adsorption. These techniques allow the phase identification of materials, show sample microstructure and quantify the pore size distribution at different scales. Furthermore, geometric parameters of sample microstructure such as grain diameter and roundness are estimated by using computer software. To conclude, results provide an enlightenment about the influence of material microstructure on the pore size distribution at two firing temperatures. These results can be useful to allow the tune of porous characteristics and, therefore, contribute to the production of more sustainable construction materials.