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Abstract Two office layouts with high and low levels of thermal control were compared, respectively traditional cellular and contemporary open plan offices. The traditional Norwegian practice provided every user with control over a window, blinds, door, and the ability to adjust heating and cooling. Occupants were expected to control their thermal environment to find their own comfort, while air conditioning was operating in the background to ensure the indoor air quality. In contrast, in the British open plan office, limited thermal control was provided through openable windows and blinds only for occupants seated around the perimeter of the building. Centrally operated displacement ventilation was the main thermal control system. Users’ perception of thermal environment was recorded through survey questionnaires, empirical building performance through environmental measurements and thermal control through semi-structured interviews. The Norwegian office had 35% higher user satisfaction and 20% higher user comfort compared to the British open plan office. However, the energy consumption in the British practice was within the benchmark and much lower than the Norwegian office. Overall, a balance between thermal comfort and energy efficiency is required, as either extreme poses difficulties for the other.

Abstract Specification by central government of the heating levels which are to be maintained in British school buildings has recently been altered. This paper is concerned with examining the nature of changes that have been made by comparing present requirements with their counterparts during the preceding one hundred years. Attention is focused on the apparently contradictory implications of these changes for those charged with responsibility for maintaining heating levels in school buildings while, at the same time, conserving fuel. It is suggested that the new statutory requirements present those who are responsible with a duty which may, in practical terms, prove difficult or costly to discharge. Although discussion is specifically restricted to British school buildings, issues are raised which are pertinent to attempts to integrate regulation of heating with control of fuel consumption in other types of non-domestic buildings both in Britain and abroad.

Abstract Steady-state free and forced convective cooling of vertical, rectangular, 3 mm thick, 250 mm long fins, uniformly separated and protruding vertically upwards from a 250 mm × 190 mm isothermal horizontal base was investigated. For each combination of specified fin protrusion, horizontal forced air flow-rate in the direction along the fins and fin base temperature, the optimal fin spacing—corresponding to the maximum rate of heat loss—has been deduced. As the fin protrusion of the heat exchanger increases, this optimal value rises significantly in forced convection conditions, but declines slightly in the presence of free convection alone. The temperature distributions over the fins' surfaces were also studied, when the fin base was maintained at constant temperatures of either 40°C, 60°C or 80°C above that of the ambient environment. Large temperature depressions occurred near the leading edges and tips of the fins in forced convection, whereas much nearer isothermal temperature distributions were present under free convection conditions.

Abstract Algae have been considered as a promising biodiesel feedstock. One of the major factors affecting large-scale algae technology application is poor wintering cultivation performance. In this study, an integrated approach is investigated combining freshwater microalgae Chlorella zofingiensis wintering cultivation in pilot-scale photobioreactors with artificial wastewater treatment. Mixotrophic culture with the addition of acetic acid (pH-regulation group) and autotrophic culture (control group) were designed, and the characteristics of algal growth, lipid and biodiesel production, and nitrogen and phosphate removal were examined. The results showed that, by using acetic acid three times per day to regulate pH at between 6.8 and 7.2, the total nitrogen (TN) and total phosphate (TP) removal could be increased from 45.2% to 73.5% and from 92.2% to 100%, respectively. Higher biomass productivity of 66.94 mg L−1 day−1 with specific growth rate of 0.260 day−1 was achieved in the pH-regulation group. The lipid content was much higher when using acetic acid to regulate pH, and the relative lipid productivity reached 37.48 mg L−1 day−1. The biodiesel yield in the pH-regulated group was 19.44% of dry weight, with 16–18 carbons as the most abundant composition for fatty acid methyl esters. The findings of the study prove that pH adjustment using acetic acid is efficient in cultivating C. zofingiensis in wastewater in winter for biodiesel production and nutrient reduction.

Abstract The pressure-loss coefficient for a duct junction of square cross-section was determined using computational fluid dynamics (CFD). The predicted junction pressure-loss coefficient for combining flows was generally in good agreement with experimental data from the literature. The junction pressure-loss coefficient was associated with the flow from the side branch to the duct carrying the total flow.

Abstract A coiled-pipe exchanger was employed to extract heat rapidly at relatively high temperatures from a 90-litre hot-water charged tank, the water being initially at a temperature of approximately 80°C. The free-convective movements of the water around the outside of the coiled pipe (immersed in the store) were due to buoyancy forces induced by colder water being forced through the heat-exchanger's pipe. For the heat-exchanger orientations tested, the maximum effectiveness, with respect to the quality of the heat extracted was achieved (i) by having the axis of the coiled heat-exchanger arranged horizontally with its inlet at the lowest level; and (ii) with the lower rate tested (=6·6 litre/min) of water being passed through the heat-exchanger's pipe, partly because this led to a lower rate of disruption of the stratification of the water within the store.

Presentation des resultats des etudes realisees par Mandix pour the Welsh Development Agency concernant l'impact sur l'environnement de l'utilisation de l'energie et sur la necessite economique et ecologique d'une utilisation rationnelle de l'energie.Analyse de l'impact sur le plan d'occupation des sols et l'infrastructure des villes et des regions.Application a la vallee de Taff (Pays de Galles).

Abstract A promising and shortly emerging energy supply chain network based on residential-scale microgeneration through micro combined heat and power systems is proposed, modeled and optimized in this work. Interchange of electrical energy can take place among the members of this domestic microgrid, which is connected to the main electrical grid for potential power interchange with it. A mathematical programming framework is developed for the operational planning of such energy supply chain networks. The minimization of total costs (including microgeneration system’s startup and operating costs as well as electricity production revenue, sales, and purchases), under full heat demand satisfaction, constitutes the objective function in this study. Additionally, an alternative microgrid structure that allows the heat interchange within subgroups of the overall microgrid is proposed, and the initial mathematical programming formulation is extended to deal with this new aspect. An illustrative example is presented in order to highlight the particular significance of selecting a proper optimization goal that thoroughly takes into account the major operational, technical and economic driven factors of the problem in question. Also, a number of real-world size case studies are used to illustrate the efficiency, applicability and the potential benefits of the microgeneration energy supply chain networks suggested in this study. Finally, some concluding remarks are drawn and potential future research directions are identified.

Abstract In order to account for variations in the performances of buildings, it is necessary to construct explanatory models of water and energy consumptions. In this paper, a modelling approach is illustrated for those parts of the variances in consumptions of water and energy that are neglected in conventional monitoring and targeting procedures. It is shown that these parts of the consumption variance need not be random and that identifying an autoregressive component can generate better models. Additionally, conventional procedures do not exploit the seasonality that is common in many buildings. Such improved models permit the more reliable detection of significant changes in a building’s performance, and more accurate estimations of the effects of changes, whether the result of plant faults or operator intervention.