Steady state analysis of a storage integrated solar thermophotovoltaic (SISTPV) system

This paper presents the theoretical analysis of a storage integrated solar thermophotovoltaic (SISTPV) system operating in steady state. These systems combine thermophotovoltaic (TPV) technology and high temperature thermal storage phase-change materials (PCM) in the same unit, providing a great potential in terms of efficiency, cost reduction and storage energy density. The main attraction in the proposed system is its simplicity and modularity compared to conventional Concentrated Solar Power (CSP) technologies. This is mainly due to the absence of moving parts. In this paper we analyze the use of Silicon as the phase change material (PCM). Silicon is an excellent candidate because of its high melting point (1680. K) and its very high latent heat of fusion of 1800. kJ/kg, which is about ten times greater than the conventional PCMs like molten salts. For a simple system configuration, we have demonstrated that overall conversion efficiencies up to ~35% are approachable. Although higher efficiencies are expected by incorporating more advanced devices like multijunction TPV cells, narrow band selective emitters or adopting near-field TPV configurations as well as by enhancing the convective/conductive heat transfer within the PCM. In this paper, we also discuss about the optimum system configurations and provide the general guidelines for designing these systems. Preliminary estimates of night time operations indicate it is possible to achieve over 10. h of operation with a relatively small quantity of Silicon

Authenticity in the bureau-enterprise culture: the struggle for authentic meaning

This article emphasises the extent to which conceptions of authenticity are forged through social interaction and socially mediated identities and how, in turn, authentic leadership involves the transformation of the organisational, social or cultural order in which leadership is situated. The overarching context for this exploration of authentic leadership is the loss of authentic meaning inherent in modern times and the importance of developing a fulfilled identity as a way of developing the possibility of meaning. An analytical distinction is made between three dimensions of authenticity (personal, ideal, social) before turning to the specific social context constituted by the contemporary modern era. This context—the enhancement of entrepreneurialism in public sector organisations which gives rise to bureau-enterprise culture—is outlined and, building on sociological work by the author, the nature of social authenticity and identities, and how they interlink with the other dimensions in this culture, are explored. The task for educational leadership concerned with authenticity is, it is proposed, to take a strategic approach to searching out and maximising the democratic potential within contemporary trends towards the bureau-enterprise culture.Peer reviewe