Optimization of the design of polygeneration systems for the residential sector under different self-consumption regulations

Polygeneration systems enable natural resources to be exploited efficiently, decreasing CO2 emissions and achieving economic savings relative to the conventional separate production. However, their economic feasibility depends on the legal framework. Preliminary design of polygeneration systems for the residential sector based on the last Spanish self-consumption regulations RD 900/2015 and RD 244/2019 was carried out in Zaragoza, Spain. Both regulations were applied to individual and collective installations. Several technologies, appropriate for the energy supply to residential buildings, for example, photovoltaics, wind turbines, solar thermal collectors, microcogeneration engines, heat pump, gas boiler, absorption chiller, and thermal and electric energy storage were considered candidate technologies for the polygeneration system. A mixed integer linear programming model was developed to minimize the total annual cost of polygeneration systems. Scenarios with and without electricity sale were considered. CO2 emissions were also calculated to estimate the environmental impact. Results show that RD 900/2015 discourages the investment in self-consumption systems whereas the RD 244/2019 encourages them, especially in renewable energy technologies. Moreover, in economic terms, it is more profitable to invest in collective self-consumption installations over individual installations. However, this does not necessarily represent a significant reduction of CO2 emissions with respect to individual installations since the natural gas consumption tends to increase as its unit price decreases because of the increase of its consumption level. Thus, more appropriate pricing of natural gas in residential sector, in which its cost would not be reduced when increasing its consumption, would be required to achieve significant CO2 emissions reduction. In all cases, the photovoltaic panels (PV) are competitive and profitable without subsidies in self-consumption schemes and the reversible heat pump (HP) played an important role for the CO2 emissions reduction. In a horizon to achieve zero CO2 emissions, the net metering scheme could be an interesting and profitable alternative to be considered

Configured distribution of the celiac artery in blue-fronted amazon (Amazona aestiva)

Foram descritas a origem e a distribuição da artéria celíaca em 20 papagaios-verdadeiros (Amazona aestiva), por meio do preenchimento do sistema arterial com solução de látex corado, fixado em solução de formol, para posterior dissecação de seus ramos colaterais. Como primeiro ramo, a artéria célica emitiu a artéria proventricular dorsal, que seguiu para o ventrículo como artéria gástrica dorsal e, em seguida, enviou a artéria proventricular ventral, que em 85% dos exemplares se originou diretamente da artéria celíaca, ou do seu ramo esquerdo em 15%. Em 25% dos casos, a artéria esplênica foi emitida antes da bifurcação em ramo esquerdo e direito. O ramo esquerdo foi responsável pela origem de ramos proventriculares, ramos pilóricos, artéria esplênica e artéria proventricular ventral, a qual emitiu ramos ao proventrículo e ao esôfago. A artéria celíaca também originou as artérias gástrica ventral e gástrica esquerda, que foram responsáveis pela emissão da artéria hepática esquerda. O ramo direito emitiu artérias esplênicas − que variaram de uma a sete −, duodenal − destinada ao segmento mais caudal da alça ascendente do duodeno, hepática direita − para o lobo direito do fígado. Em seu segmento terminal, o ramo direito dividiu-se em artérias gástrica direita − para o ventrículo −, pancreaticoduodenal − para o pâncreas, alças ascendente e descendente do duodeno e segmentos cranial do íleo e caudal do jejuno. A irrigação determinada pela artéria celíaca nos papagaios segue o que é proposto para aves de outros gêneros, apresentando divergências como ausência das artérias vesicular e ileocecal, bem como da vesícula biliar e ceco. _________________________________________________________________________________ ABSTRACTThis research was performed aiming to describe the origin and the distribution of the celiac artery in 20 blue fronted amazon (Amazona aestiva), through the completion of their circulatory system with an aqueous solution of colored latex, followed by fixation in formol for later dissection of the collateral branches. The first branch emitted the proventricular dorsal artery that headed to the ventricle as gastric dorsal artery and next emitted the proventricular ventral artery which originated on the celiac artery in 85% of the cases and in 15% had its origin on the left branch of the celiac artery. In 25% of the cases the splenic artery was emitted before the bifurcation on left and right branches. The left branch was responsible for the origin of the proventricular branches, piloric branches, splenic artery and proventricular artery, which emitted branches to the proventricle and esophagus. The celiac artery also emitted the gastric ventral artery and left gastric. The right branch emitted splenic arteries (that varied from a number of seven); duodenal bound for the more caudal segment of the ascendant segment of the duodenum and the right hepatica to the right liver lobe. On its terminal segment the right branch was divided into right gastric arteries to the ventricle and pancreaticduodenal to the pancreas, ascendant and descendant braces of the duodenum and to the cranial segments of the ileum and caudal of the jejune. The irrigation provided by the celiac artery in parrots remains the same as described for other bird genders showing as divergences: the lack of vesicular arteries and ileocecal as well the gall bladder and the cecos