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In the context of desperate poverty, characterized by households at subsistence level that experience economic loss and social fracture, explanations for why individuals undertake entry into entrepreneurship are limited. We find that individuals rely on their social relationships to enable entrepreneurial activities that have the potential to create a reasonable income gain. In a sample of 1,049 households in rural Kenya, we test whether the disintegration of social structure attenuates entrepreneurial behavior. When coupled with factors such as income loss, gender of the household head, and access to communal resources, social structure plays a pivotal role in entrepreneurial action. We propose that the search for reasonable income gain is a key driver of entrepreneurial action at subsistence levels, thereby adding to behavioral explanations of entrepreneurship.

Marine current turbines are still in their infancy with many devices at the development stage. Studies are often carried out using small scale laboratory experiments in flumes, towing tanks and numerical simulations to investigate the wakes and performance of scale marine current turbines. However, the characteristics of the inflow turbulence used in such studies is often not fully considered. Tidal flows are highly turbulent with a broad range of eddy sizes and intensities. So differences are expected when predictions of array energy yields are made from towing tanks studies with zero turbulence. This work considers the effects of turbulent eddy size on the thrust and wake behind a porous disc rotor simulator commonly used to represent marine current turbines in small scale experiments. The results show an increase in thrust coefficient with increasing length scale and a corresponding reduction in velocity deficit in the wake. These findings have implications to array special planning and hence energy yields.

This paper investigates the impact of current user behaviour on the carbon savings from retrofit measures including Mechanical Ventilation with Heat Recovery (MVHR) in a council owned 107-flat tower block. Prior to the retrofit, temperature and relative humidity monitoring was undertaken in 18 flats for 35 days. The measurements were then used to develop occupant behaviour profiles and their relation to the heating system. Dynamic thermal simulation of the flats pre- and post-retrofit was performed using TRNSYS, with the identified user behaviour profiles as the key parameter. The results highlight that for these fuel poverty constrained flats the estimated carbon savings of retrofit will be typically half those predicted using standard rules for temperature in living spaces.

Tidal flows suitable for the installation of tidal stream turbines are highly turbulent with a broad range of turbulent scales, and intensities of around 10%. It is important to understand how turbulent flows affect the performance and wake profiles for the accurate prediction of the performance of single devices and arrays. Previous studies have considered the effects of turbulence intensity, but the effects of turbulent eddy size have not been investigated. This paper presents a new method for generating turbulence in large eddy simulations of uniform actuator disc rotor models. The advantage of the gridded actuator disc is that the generated turbulence may be controlled, so the effects of turbulence length scale and intensity may be investigated. Initial results show the wake recovery is faster behind a rotor generating larger turbulent length scales and intensities, with a corresponding increase in axial induction and thrust. Therefore turbines may be positioned closer together if they generate more turbulence, increasing the power output of an array for a given area, although the individual device performance may be lower. Future work will consider the effects of free-stream turbulence on the performance and wake profiles of the gridded actuator disc, and validation against experimental data.

It has previously been shown that ambient turbulence affects the results from computational fluid dynamics (CFD) models when using an actuator disc to simulate marine current turbines. The turbulence parameters are often estimated using an empirical equation that is dependent on a turbulence length scale. In most literature this length scale is commonly highlighted as the authors ‘best guess’ with little scientific reasoning. The work presented here investigates the effects of using different length scales on the development of a flow in a circulating water channel. The results showed that the best agreement is achieved with a length scale of one third the channel depth. The obtained turbulence parameters were then used with an actuator disc model. Agreement with experimental data was initially poor as the velocity deficit was severely under predicted. The addition of a turbulence source at the disc improved the agreement with experimental data significantly. It was found that the length scale of the disc turbulence should be the diameter of the holes used on the porous discs for experiments. However, there were still discrepancies between the experimental and model turbulence intensities. A possible cause of this may be that the turbulence intensity added at the disc was under predicted. Further work is needed to establish if better agreement can be achieved by increasing the turbulence at the disc.

England, Scotland and Wales planning regulations require zero carbon homes by 2016. This can be expected to accelerate the uptake of microgeneration technologies. To incentivise small low-carbon generators the UK Department of Energy and Climate Change (DECC) proposed two new systems: the Feed-in Tariffs (FIT) and the Renewable Heat Incentive (RHI). This paper investigates the impact of these two systems on the carbon performance and the economics of various microgeneration technologies under two scenarios: (a) at the single dwelling level and (b) a local microgrid at the street level. The economic implications of combining a number of houses to form a local microgrid are assessed and expressed in terms of percentage of capital investment outstanding. The paper concludes that the current structure of the FIT and RHI does not incentivise microgeneration technologies according to their carbon performance and does not favour street-level schemes such as the one investigated in this paper. However it is sufficient to drive the market forward.

This paper presents a pilot study which considers the overheating risk of classrooms in school buildings. Four schools in Southampton in the South of the UK, constructed during the period of the 1950s- 1980s were used as case study examples. The schools were studied in terms of the parameters or the combination of parameters that may drive classroom overheating. Topographic features, built-up area, urban density, adjacency to roads and parks and other characteristics such as building form and materials were assessed, looking at the urban, building and classroom scale. In addition to this a questionnaire survey was conducted to assess the teachers’ perception of their classrooms’ thermal environment. The survey responses are discussed and compared to the outcomes of the school parameter analysis, also considering the limitations of the survey approach. It was found that gaining an understanding of the occupants’ perception of the thermal conditions in a school’s classrooms is essential for developing recommendations for addressing overheating. The study appears to indicate that individual perception of overheating may outweigh the objective influence of urban design and construction parameters on the indoor thermal conditions.

This paper presents findings from an experimental study investigating the downstream wake response from marine current energy convertors operating in various degrees of vertical flow constraint. The paper investigates deep vertically unconstrained sites, mid-depth sites and there is a particular emphasis on shallow tidal stream sites. Shallow tidal resources could be utilised for the deployment of first generation farms. The nature of the downstream wake flow will be a critical factor when determining the farm layout and the wake length is heavily influenced by the flow depth or ratio of rotor diameter to flow depth. A porous actuator disk is used to model the marine current energy convertor and an Acoustic Doppler Velocimeter is used to map the downstream wake. Linear scaling of length ratios suggests mid depth sites of 30-50m will produce the shortest wake lengths and for deeper and shallower sites the wake length increases. It is hoped that these relationships between vertical flow constraint and wake length will help with the layout design of tidal stream farms

The Energy Saving Trust’s work in small-scale domestic wind dates back to 2005. A report compiled for the DTI1 concluded that ‘with the appropriate support, small wind could supply four per cent of the UK electricity requirement and reduce domestic CO2 emissions by six per cent’. Subsequently, our reports ‘Microwind Electricity Generation in the UK Residential Sector’ and ‘Generating the Future’, both completed in 2007, provided further predictions of the potential market for small wind turbines in the UK by 2050. These projections were based on modelled data and were produced before actual performance data from small-scale wind turbines was widely available. As such, it was difficult at the time to determine the accuracy of such future projections. Since these reports were published, the UK market for domestic small-scale wind has developed rapidly.