Adaptive Comfort Degree-Days: an index to compare adaptive comfort standards and estimate changes in energy consumption for future UK climates

This paper introduces the concept of the Adaptive Comfort Degree-Day, a temperature difference/time composite metric, as a means of comparing energy savings from Adaptive Comfort Model standards by quantifying the extent to which the temperature limits of the thermal comfort zone of the Predicted Mean Vote Model can be broadened. The Adaptive Comfort Degree-Day has been applied to a series of climates projected for different locations (Edinburgh, Manchester and London) under different emissions scenarios in the United Kingdom for the 2020s, 2030s, 2050s and 2080s. The rate at which energy savings can be achieved by the European adaptive standard EN15251 (Category II) was compared with the ASHRAE 55 adaptive standard (80% acceptability) during the cooling season. Results indicate that the wider applicability of the European standard means that it can realise levels of energy savings which its counterpart ASHRAE adaptive standard would not achieve for decades

An assessment of the potential returns of energy certificates for the UK household sector

Purpose – This article seeks to investigate the interconnections between the expectations of the impact of energy certificates issued within the UK domestic building sector through the Energy Performance of Buildings Directive (EPBD) and the actual number and financial implications of the energy saving measures (ESMs) achieved. Design/methodology/approach – The methodology uses two previously published surveys and compares these with a third independent survey by the authors focusing upon the discrepancies between planned action and implemented action, introducing the term human factor element (hfe). Findings – The article concludes that annual carbon savings arising from implementation of the Energy Performance Certificate (EPC) may be as low as 73.4?ktC over the five year term of the Kyoto Protocol even though 44 per cent of energy saving measure costs of £200 million are recouped within the same time period and savings will continue for up to 40 years. Achieving annual savings of only 14.7?ktC by 2010, such a figure represents a mere 0.3 per cent of the annual domestic 4.8?MtC savings announced by the government in its 2006 Climate Change Programme. Practical implications – Since the principal determinant in the uptake of ESMs is initial cost, it is considered that the EPBD is likely to remain an under-performing instrument in the promotion of energy sufficiency until such time as other complementary provisions are introduced. Originality/value – Sheds light upon the likely financial impact upon energy efficiency in domestic buildings by energy certificates

Quantification Of Rigidity And Synthesis Of Cyclobutane Bisimide Building Blocks

The quantification of a molecule’s conformational rigidity was achieved via development of a new measure called the Rigidity Factor, Rgf. This value is a unit interval wherein molecules with corresponding Rgf values closer to 1 are rigid and values closer to 0 are more flexible. The value is determined as a ratio between the molecule’s Van der Waals volume, VW, and it’s Van der Waals potential volume, VWpot. The VWpot was defined as the minimum total volume occupied by a rotamer ensemble of the molecule which has been aligned according to the RMSD for all heavy atoms to achieve a minimum volume. The rotamer ensembles were constructed using CREST (a tool in the xtb suite of programs) or Gromacs. The volumes were calculated using a custom Python script written for this project which uses a Monte Carlo volume approximation method. The script was written to take advantage of parallel computing architecture when present.The Rgf was calculated for several series of similarly structured molecules. These series include straight-chain alkanes, cycloalkanes, diols, diacids, and polymer repeat groups. The values for each series fit the expected trend of longer backbones having a greater flexibility and thus lower Rgf. It was observed that rotamer ensembles which represented a molecule with the capability of intramolecular hydrogen bonding, these rotamers dominate the ensemble. This gives a higher Rgf than expected and is more similar to a cyclic isomer of similar length. In one case, the repeat unit for polybutylene succinate, PBS, the H-bond donors were replaced with methyl groups. This destroyed intramolecular H-bond potential and the Rgf of the molecule more closely resembled the expected value. Conformational entropy, Sconf, for each compound was calculated using CREST. These values were plotted against Rgf for each compound and found to have a general correlation, i.e. structures with lower Rgf have higher Sconf. Several compounds were identified which had a higher-than-expected Sconf despite having a very high Rgf. It was theorized that degenerate rotamers born from the rotation of methyl groups provide this entropy. Since these structures are spatially and volumetrically equivalent, this rotation is not reflected in Rgf calculations. A series of new cyclobutane-containing, difunctional monomers (CBDx) was developed for the intention of being used in polymeric materials. Two polymers were synthesized using two different CBDxs and were shown to be colorless and very lightweight. The monomers were built on a maleic anhydride skeletal core and each contain a central cyclobutane moiety created in the key [2+2]photocycloaddition step between two maleic anhydride or imide olefins. This key step was achieved using low power, fluorescent UV-A light sources. By using these sources, the syntheses were much more efficient and safer than traditional photochemical reactions which often necessitate the use of specialized glassware to mitigate the dangers of the broad-spectrum UV bulbs employed. A poly(cyclobutanebutanebisimide), or PCBBI-1, was synthesized using a cyclobutane-containing diester (CBDE-6) and 1,7-heptandiol. The polymer was confirmed via NMR and HRMS of the soluble oligomeric components. The bulk material had a foamy texture with a very low density. The polymer was colorless. A second polymer, PCBBI-2, was synthesized using a cyclobutane-containing diol (CBDO-2) and adipic acid. The extremely poor solubility of the material precluded NMR or HRMS analysis. Polymerization was assumed based on physical characteristics of bulk material which was extremely similar to PCBBI-1. A classic [2+2] photocycloaddition reaction between maleic anhydride and dissolved ethylene gas was improved on the measures of safety, efficiency, and reduced complexity. This was achieved by using a UV source which targeted the absorption of the maleic anhydride starting material. In doing so, the use of high-power UV photoreaction bulbs can be avoided. This eliminates the need for specialized cooling glassware thus reducing apparatus complexity. An isolated yield of 70% was achieved via vacuum distillation after 5 days reaction time. A similar reaction using acetylene gas was performed but did not provide the same high efficiency. However, the reaction was a success as a crystal structure of the desired product was collected for the first time. Additionally, a new polymorph of a side product of the reaction, biscyclopropanedicarboxylic anhydride, CPDAn-1, was collected. In total, 21 compounds are presented here. Aside from maleimide and its photo dimer, all of these compounds are either not present or virtually ignored in literature for various reasons as discussed. Eleven of these compounds are novel and initial characterizations are presented herein. Further characterizations are provided for the remainder. Characterization includes 10 initial crystal structures reported for both novel and extant species

Diffraction grating characterisation for cold-atom experiments

We have studied the optical properties of gratings micro-fabricated into semiconductor wafers, which can be used for simplifying cold-atom experiments. The study entailed characterisation of diffraction efficiency as a function of coating, periodicity, duty cycle and geometry using over 100 distinct gratings. The critical parameters of experimental use, such as diffraction angle and wavelength are also discussed, with an outlook to achieving optimal ultracold experimental conditions