Design and control optimisation of adaptive insulation systems for office buildings. Part 1: Adaptive technologies and simulation framework

The increasing insulation levels imposed by building regulations have the effect of reducing heating energy use, while increasing cooling energy use and/or reducing thermal comfort especially in summer. Adaptive insulation technologies could provide an opportunity to reduce building energy use while simultaneously improving indoor environmental quality, but there is a lack of information about the performance of these novel technologies. This paper is the first of a two part study, which aims to evaluate the performance of adaptive insulation. Part 1 proposes a simulation framework for optimising adaptive insulation design and control parameters and explains its implementation. The customised simulation strategy optimises design and control aspects of adaptive building envelopes by minimising the total primary energy use and thermal discomfort within a building. Moreover the simulation model for adaptive insulation is validated qualitatively. Part 2 applies this framework in a parametric study to explore the potential of adaptive insulation.The British authors would like to acknowledge support from EPSRC Doctoral Training Grant (EP/K503009/1) and project RG70518, funded by Wintech ltd. The Chinese author would like to acknowledge the financial supports from the National Natural Science Foundation of China (Grant No. 51408427)

Design and control optimisation of adaptive insulation systems for office buildings. Part 2: A parametric study for a temperate climate

This paper is the second of a two part study, which aims to evaluate the performance of adaptive insulation. Part 1 proposes a simulation framework for optimising adaptive insulation design and control parameters, it describes its implementation, and validates the simulation strategy qualitatively. This second paper applies the simulation framework, by means of a parametric study on a specific building typology in a particular climatic region, to explore the potential of adaptive insulation in this context. Alternative adaptive insulation configurations and control strategies for opaque wall applications are evaluated, for an office room in a temperate climate of Shanghai, in order to optimise two design objectives: total primary energy saving and thermal comfort. It is found that adaptive insulation, when properly designed and controlled, has significant potential to improve both design objectives simultaneously. For the case study considered in this paper, yearly energy savings and thermal comfort improvements of up to 50% could be achieved by adaptive insulation compared to an equivalent astatic insulation alternative. The performance improvements of the adaptive insulation depend on the design choices (thermal mass, position of the adaptive insulation, switching range of insulation) and control strategy adopted.The Chinese author would like to acknowledge the financial supports from the National Natural Science Foundation of China (Grant No. 51408427). The British authors would like to acknowledge support from EPSRC Doctorial Training Grant (EP/503009/1) and project RG70518, funded by Wintech ltd. The authors would like to thank EU Cost Action TU1403 "Adaptive Facades Network" for providing excellent research networking

Review of current status, requirements and opportunities for building performance simulation of adaptive facades^†

Adaptive building envelope systems have the potential of reducing greenhouse gas emissions and improving the energy flexibility of buildings, while maintaining high levels of indoor environmental quality. The development of such innovative materials and technologies, as well as their real-world implementation, can be enhanced with the use of building performance simulation. Performance prediction of adaptive facades can, however, be a challenging task and the information on this topic is scarce and fragmented. The main contribution of this review article is to bring together and analyze the existing information in this field. In the first part, the unique requirements for successful modeling and simulation of adaptive facades are discussed. In the second part, the capabilities of five widely-used building performance simulation tools are reviewed, in terms of their ability to model energy and occupant comfort performance of adaptive facades. Finally, it discusses various ongoing trends and research needs in this field.The authors would like to thank EU Cost Action TU1403 “Adaptive Facades Network” for providing excellent research networking. The Dutch authors acknowledge the support from RVO EOSLT08016 project FACET. The British authors would like to acknowledge the support from EPSRC and project RG70518, funded by Wintech ltd.This is the published manuscrip

Occupant-Centred Control strategies for Adaptive Facades: A preliminary study of the impact of shortwave solar radiation on thermal comfort

Adaptive facades have the potential to shape resource-efficient and occupant-centred spaces only when their control strategies are tailored to meet transient, local and personal demands. State-of-the-art control algorithms are currently failing to provide occupant thermal satisfaction because the data on occupant response to the thermal environment is not sufficiently granular. This paper presents a preliminary assessment of the use of the adjusted operative temperature, which accounts also for the additional effect of shortwave radiation on occupants, to dynamically devise learning control strategies that meet individual occupant comfort requirements. Shortwave effects of solar radiation on occupant comfort and operative temperature are compared to those considering only longwave radiation and two alternative occupant-centred control strategies are devised and assessed. Lastly, a combined occupant-centred control strategy is also proposed for an open space office

Letters and records of the dissenting congregations: David Crosley, Cripplegate and Baptist Church life

The original publication is available at www.springerlink.comInternational audienceThis chapter examines the status and function of letters in manuscript records of dissenting Churches of the post-Toleration years, concentrating on the correspondence of the Baptist Church of Cripplegate. The letters are placed in the context of controversies about Church government and discipline and the rhetoric used during the scandal caused by the excommunication of its Northern minister David Crosley for drinking, lying and adultery is assessed. In doing so, the chapter pays particular attention to the epistolary exchanges between metropolitan and provincial congregations and to what they reveal about conceptions of the Baptist ministry

3D Lowest Landau Level Theory Applied to YBCO Magnetization and Specific Heat Data: Implications for the Critical Behavior in the H-T Plane

We study the applicability of magnetization and specific heat equations derived from a lowest-Landau-level (LLL) calculation, to the high-temperature superconducting (HTSC) materials of the YBa$_2$Cu$_3$O$_{7-\delta}$ (YBCO) family. We find that significant information about these materials can be obtained from this analysis, even though the three-dimensional LLL functions are not quite as successful in describing them as the corresponding two-dimensional functions are in describing data for the more anisotropic HTSC Bi- and Tl-based materials. The results discussed include scaling fits, an alternative explanation for data claimed as evidence for a second order flux lattice melting transition, and reasons why 3DXY scaling may have less significance than previously believed. We also demonstrate how 3DXY scaling does not describe the specific heat data of YBCO samples in the critical region. Throughout the paper, the importance of checking the actual scaling functions, not merely scaling behavior, is stressed.Comment: RevTeX; 10 double-columned pages with 7 figures embedded. (A total of 10 postscript files for the figures.) Submitted to Physical Review

Extreme Type-II Superconductors in a Magnetic Field: A Theory of Critical Fluctuations

A theory of critical fluctuations in extreme type-II superconductors subjected to a finite but weak external magnetic field is presented. It is shown that the standard Ginzburg-Landau representation of this problem can be recast, with help of a novel mapping, as a theory of a new "superconductor", in an effective magnetic field whose overall value is zero, consisting of the original uniform field and a set of neutralizing unit fluxes attached to $N_{\Phi}$ fluctuating vortex lines. The long distance behavior is related to the anisotropic gauge theory in which the original magnetic field plays the role of "charge". The consequences of this "gauge theory" scenario for the critical behavior in high temperature superconductors are explored in detail, with particular emphasis on questions of 3D XY vs. Landau level scaling, physical nature of the vortex "line liquid" and the true normal state, and fluctuation thermodynamics and transport. A "minimal" set of requirements for the theory of vortex-lattice melting in the critical region is also proposed and discussed.Comment: 28 RevTeX pages, 4 .ps figures; appendix A added, additional references, streamlined Secs. IV and V in response to referees' comment

Scaling critical behavior of superconductors at zero magnetic field

We consider the scaling behavior in the critical domain of superconductors at zero external magnetic field. The first part of the paper is concerned with the Ginzburg-Landau model in the zero magnetic field Meissner phase. We discuss the scaling behavior of the superfluid density and we give an alternative proof of Josephson's relation for a charged superfluid. This proof is obtained as a consequence of an exact renormalization group equation for the photon mass. We obtain Josephson's relation directly in the form $\rho_{s}\sim t^{\nu}$, that is, we do not need to assume that the hyperscaling relation holds. Next, we give an interpretation of a recent experiment performed in thin films of $YBa_{2}Cu_{3}O_{7-\delta}$. We argue that the measured mean field like behavior of the penetration depth exponent $\nu'$ is possibly associated with a non-trivial critical behavior and we predict the exponents $\nu=1$ and $\alpha=-1$ for the correlation lenght and specific heat, respectively. In the second part of the paper we discuss the scaling behavior in the continuum dual Ginzburg-Landau model. After reviewing lattice duality in the Ginzburg-Landau model, we discuss the continuum dual version by considering a family of scalings characterized by a parameter $\zeta$ introduced such that $m_{h,0}^2\sim t^{\zeta}$, where $m_{h,0}$ is the bare mass of the magnetic induction field. We discuss the difficulties in identifying the renormalized magnetic induction mass with the photon mass. We show that the only way to have a critical regime with $\nu'=\nu\approx 2/3$ is having $\zeta\approx 4/3$, that is, with $m_{h,0}$ having the scaling behavior of the renormalized photon mass.Comment: RevTex, 15 pages, no figures; the subsection III-C has been removed due to a mistak

Systematics of two-component superconductivity in YBa2Cu3O6.95YBa_{2}Cu_{3}O_{6.95} from microwave measurements of high quality single crystals

Systematic microwave surface impedance measurements of YBCO single crystals grown in $BaZrO_3$ crucibles reveal new properties that are not directly seen in similar measurements of other YBCO samples. Two key observations obtained from complex conductivity are: a new normal conductivity peak at around 80K and additional pairing below 65K. High pressure oxygenation of one of the crystals still yields the same results ruling out any effect of macroscopic segregation of O-deficient regions. A single complex order parameter cannot describe these data, and the results suggest at least two superconducting components. Comparisons with model calculations done for various decoupled two-component scenarios (i.e. s+d, d+d) are presented. Systematics of three single crystals show that the 80K quasiparticle peak is correlated with the normal state inelastic scattering rate. Close to Tc, the data follow a mean-field behavior. Overall, our results strongly suggest the presence of multiple pairing temperature and energy scales in $YBa_{2}Cu_{3}O_{6.95}$.Comment: 14 pages, 2-column, Revtex, 5 embedded postscript figures, uses graphicx. Postscript version also available at http://sagar.physics.neu.edu/preprints.htm