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Abstract This paper presents preliminary results from the first nine months of monitoring the Oxford Solar House (OSH) which was built, in particular, to evaluate the potential for photovoltaics to contribute cost effectively to domestic energy supply in the UK. The house was built in a south facing site with good solar access. It has a 4kW PV system integrated into the roof structure and a 5m 2 solar thermal domestic hot water pre-heat. The house was designed to require a minimum of energy for heating, cooling and lighting, therefore optimizing the significance of the contribution of the solar electric supply. The performance of the PV system is presented, as well as an analysis of the whole design strategy to minimize energy loads.

Education can serve the purpose of trying to mitigate catastrophes. In a school context, teachers can have a role in enacting an interconnection between critical thinking (CT) as a potentially useful tool and education for sustainable development (ESD), in terms of educating and communicating the importance of sustainability to future generations. This paper uses discourse analysis, drawing on post-structuralism, to explore how Norwegian primary school teachers consider CT (skills, dispositions, and civic participation) in relation to ESD. The study draws on social constructivism and positioning theory (PT) in particular to find patterns in teachers’ own shifting standpoints through individual and collective assertations around ESD. Specifically, in this paper we make efforts to implement the PT to study (i) teachers’ own positioning about sustainability through their communication acts within primary-school contexts, and (ii) the functions of education in relation to ESD in this context. We explored the discussion between three teachers from the same school team during one focus group interview, by tracing the teachers’ uses of I and we (as markers) in relation to Biesta’s three functions of education in the discourse. Our discourse analysis has an exploratory character and is carried out on a limited dataset. PT was used as a framework to categorize the teachers’ statements; treated as content of discourse. The pronoun we is identified in the discourse analysis in three different ways: with the underlying meaning of a humanitarian we, an institutional we, and a classroom we. In the one focus group interview, we also identified teachers’ sense of belonging with the environment and nature, generally regarded to be prevalent in Norwegian society.

Direct characterisation of the annual performance of solar thermal and heat pump systems using a six-day whole system test

Abstract The Angstrom-Prescott (A-P) model, a highly rated model, has been widely used to estimate global solar radiation (H) at daily or monthly scales in different locations around the world. However, few studies focused on the interchangeability of the A-P coefficients at different time scales, especially finer scales. The objectives of this work were to determine the A-P coefficients at daily (TS1), 5-day (TS2), 10-day (TS3), and monthly (TS4) time scales and to investigate the variations of the A-P coefficients caused by the time intervals and how this variations impacts on H estimation. Long-term records of H (1961-2000) from a total of 15 stations in the Yangtze River basin were used in the present study. The model performance was evaluated using root mean squared error (RMSE), coefficient of determination (R2), mean absolute difference (MAD), and Pearson coefficient. Better fit were found at time scales of TS2 and TS3 (R2 = 0.86 and 0.84, respectively) between the observed and predicted H. For each station, slight differences existed between the coefficients at the studied time scales. In general, the difference in coefficients increased with the increased of time interval from TS1 to TS2, TS3 and TS4. The largest differences in the coefficients were found between TS1 and TS4. Nevertheless, further analysis demonstrated that the coefficients calibrated at finer time scale could be applied to estimate H at larger time scales with an acceptable accuracy, and vice versa. The results have significant implications to facilitate the calibration and choice of the A-P coefficients.

Solar reactors designed and constructed for thermochemical applications present different configurations and general performance. The selection of a solar reactor that optimizes a particular process is always a difficult challenge. This work studies two types of reactor configuration by means of a comparative experimental analysis. It was employed a solar device, which is able to operate as fixed reactor with packed bed samples and as rotary kiln. The reduction of CuO into Cu2O was tested under both operation modes, due to its proved potential and interest as thermochemical storage material. It was found that heat transfer was hindered in static experiments limiting the fraction of reactive sample. Thermal gradients of about 200 °C were found in the packed bed through thermocouple and IR camera measurement. Heating rates and total fed energy must be restricted at the risk of front of the sample to melt, resulting in several operation drawbacks. In contrast, mixing conditions in rotary kilns allowed for higher heating rates and led to homogenous sample temperature. Maximum reaction yields in stationary mode did not overpass 14% while it was achieved more than 80% in rotary mode at temperatures about 860 °C. Thermal efficiencies were very limited in both operation modes due to the high thermal inertia of the solar reactor. Because rotary mode admitted much more energy, its thermal efficiency was even lower than static. A solution to increase rotary kilns thermal efficiency is working in continuous mode.

Continuous-time optimization models have successfully been used to capture the impact of ramping limitations in power systems. In this paper, the continuous-time framework is adapted to model flexible hydropower resources interacting with slow-ramping thermal generators to minimize the hydrothermal system cost of operation. To accurately represent the non-linear hydropower production function with forbidden production zones, binary variables must be used when linearizing the discharge variables and the continuity constraints on individual hydropower units must be relaxed. To demonstrate the performance of the proposed continuous-time hydrothermal model, a small-scale case study of a hydropower area connected to a thermal area through a controllable high-voltage direct current (HVDC) cable is presented. Results show how the flexibility of the hydropower can reduce the need for ramping by thermal units triggered by intermittent renewable power generation. A reduction of 34% of the structural imbalances in the system is achieved by using the continuous-time model. Comment: Accepted for publication through the Power Systems Computation Conference 2020

Fuel gas production from biomass using circulating fluidised bed technology is presented in our laboratory. This improved technical concept is aiming at producing high quality gas, in terms of low tar level and particulates carried out in the fuel gas, and overall emissionstextquoteright reduction associated with fuel gas combustion, as well as stable and reliable operation with the minimum fluctuations in the producer gas volume and composition. Based on this concept, a characteristic theoretical modelling approach involving hydrodynamics, chemical reaction kinetics, and energy balance is accordingly discussed. In addition, very preliminary experimental results from a laboratory-made test rig are also given.

With increased global concerns on climate change, the need for innovative spaces which can provide thermal comfort and energy efficiency is also increasing. This paper analyses the effects of transitional spaces on energy performance and indoor thermal comfort of low-rise dwellings in the Netherlands, at present and projected in 2050. For this analysis the four climate scenarios for 2050 from the Royal Dutch Meteorological Institute (KNMI) were used. Including a courtyard within a Dutch terraced dwelling on the one hand showed an increase in annual heating energy demand but on the other hand a decrease in the number of summer discomfort hours. An atrium integrated into a Dutch terraced dwelling reduced the heating demand but increased the number of discomfort hours in summer. Analysing the monthly energy performance, comfort hours and the climate scenarios indicated that using an open courtyard May through October and an atrium, i.e. a covered courtyard, in the rest of the year establishes an optimum balance between energy use and summer comfort for the severest climate scenario.