Thermal performance in a conventional fireplace and in an inset appliance

The objective of this study is to compare the performance of the equipment currently employed in the domestic heating with firewood, the conventional fireplace and the inset appliance with close firedoors. For such, it was followed the European Standard EN13229:2001/A2:2004. Efficiency and heat output is determined and the major heat losses that penalize the appliance performance are identified and calculated. Tests in laboratory were developed in two inset appliances, and tests in situ in one conventional fireplace. One of the appliances uses only staging as primary air, and the other only grate air In inset appliances, with a heat output near 10 kW, the average efficiency varies between 67% and 73%, while in a conventional fireplace that value lies at 30%. In all these devices the major losses take place as sensible heat in the flue gases, 23% to 30 % in inset appliances and above 50% in a conventional fireplace. The second most important heat loss happens by chemical losses in the flue gases. It takes values near 17% in a conventional fireplace and may be disregarded in an inset appliance.

Bio-removal of toxic metals by metal resistant anaerobic bacteria: molecular characterization and performance studies

Tese de dout., Ciências Biotecnológicas (Biotecnologia Ambiental), Faculdade de Ciências e Tecnologia, Univ. do Algarve, 2010

Dietary biodiesel-derived crude glycerol in gilthead seabream juveniles (Sparus aurata): effects on growth performance and metabolism

In the European Union the turn towards renewable energy sources has increased the production of biodiesel from rapeseed oil, leaving glycerol (also known as glycerin) as a valuable by-product. For every litre of biodiesel produced, approximately 79 g of crude glycerol are generated. As the biodiesel production grows, the quantity of crude glycerol generated will be considerable and its utilization will become an urgent topic. One possibility is the use of crude glycerol on animal feeds. Glycerol has been evaluated as a dietary energy source for several farm animals, including fish. A study was undertaken to assess the effect of dietary biodiesel-derived glycerol (from rapeseed oil) on the overall growth performance, digestive capacity and metabolic nutrient utilization in juvenile gilthead seabream fed a low fishmeal level diet. Two practical diets were formulated to be isonitrogenous (crude protein, 45.4% DM), isolipidic (18.5% DM) and isoenergetic (gross energy, 21.3 kJ/g DM). The control diet (CTRL) was formulated with intermediate levels of marine-derived proteins (19%). In the same basal formulation, 5% glycerol (GLY) was incorporated at the expenses of wheat. Each dietary treatment was tested in triplicate tanks over 63 days, with 20 gilthead seabream (Sparus aurata), with a mean initial body weight (IBW) of 27.9  0.12 g. At the end of the trial, fish fed the CTRL diet reached a final body weight of 84.3  2.2 g (more than 3-fold increase of initial body weight). Fish fed the GLY diet showed a significantly higher (P<0.05) growth, expressed in terms of final body weight and specific growth rate. Voluntary feed intake was similar between the two treatments, but both feed efficiency and protein efficiency ratio were significantly improved (P<0.05) in fish fed the GLY diet. Dietary glycerol had no effect (P>0.05) on the apparent digestibility of protein. In comparison to the control treatment, dietary glycerol significantly improved (P<0.05) protein and fat retention. Activities of digestive enzymes were significantly affected by the various dietary treatments. Fish fed the GLY diet showed an enhanced activity of alkaline phosphatase (ALP) and pepsin, while activities of lipase and leucine-alanine peptidase (LAP) were little affected by dietary glycerol. Fish show the ability to use crude glycerol as a dietary energy substrate.