162 research outputs found
Retrofitting homes for a recessionary era; energy efficiency retrofitting services (EERS) sector characteristics and routes to increased activity
Full text linkWithin the UK, energy efficiency improvements within the existing housing stock is a key area in which governments have attempted to increase rates of activity to boost carbon reduction and end user cost savings. The most recent UK policy, the Green Deal, was a pay as you save scheme, linking the capital cost of improvements to ongoing energy bill payments.
The success of this policy was limited, with minimal uptake in comparison to expectations. This research investigates the viewpoints of retrofit industry practitioners, to assess their experiences of working under the Green Deal, and evaluate what pathways could be available to move forward into the future. UK and German based individuals interviews were used to compare experiences, along with UK group interviews and focus groups to develop findings via a grounded theory approach, to illuminate possible future strategies for UK retrofit.
Key findings suggest EERS expansion is most successful if policies are designed more holistically; UK policies show strategies which focus on simply the property and not the occupants have their disadvantages. Therefore, a move away from marginal financial incentives, such as the Green Deal's loan structure, to a wider consideration of how policy tools interact with supply chains and end users, would enable increased impact. Precise strategies identified to achieve this include; EERS sector members providing an attractive investment prospect to customers external to any government subsidy, linking of energy efficiency improvements with more standard property upgrades, and an increase in training levels to increase professionalism
A study of socio-spatial behaviour in traditional and contemporary shopping environments in Dubai, UAE
Full text linkShopping as a phenomenon which has existed since the early history of humanity to
meet human needs, has become one of the main daily life activities. Traditional
shopping environments are places where people in the past spent their time
shopping, talking to each other and discussing their issues. Today, shopping
environments are constructed in a modern architectural style and at much larger
scales. Arab and Islamic countries met with the initial concept of shopping malls in
the 1980s, which have become more common in most Arab countries in recent years.
The United Arab Emirates (UAE) is one of these countries where, as a result of rapid
economic growth, modern shopping environments have proliferated. These modern
shopping environments do not relate to the physical and cultural contexts of UAE.
Dubai, which has become an important tourist destination, is an Arab Islamic city
with several souks (traditional markets in the Arab world).
This research aims to develop our knowledge and understanding of the shopper’s
socio-spatial behaviour within the built environment in traditional and contemporary
shopping environments in Dubai, UAE. It addresses this issue through an in-depth
investigation of human perceptions and activities in a traditional souk (Souk Naif)
and a shopping mall (Dubai Mall).
The research methods divided into two stages: the first stage is based on qualitative
methods, which include literature review, analysis of documents, and physical
survey of the buildings. The second stage combines quantitative and qualitative
methods including a questionnaire (mostly quantitative, with a couple of questions
focusing on reasons for people’s behaviour and motivations) and two types of
unobtrusive observation – snapshot and individual behaviour mapping (qualitative
methods which generate quantitative data).
Shopping malls seem to encourage the involvement of young people, especially
shoppers who are 20-29 year, within the shopping environment more than traditional
souks, which the research showed older shoppers in Dubai still prefer. Malls, as
modern shopping places, display more density, longer duration and slower speed of
shoppers' behaviour in contrast to the lower density, shorter duration and faster speed
of shoppers' behaviour in souks
Energy yield enhancement of bifacial photovoltaic modules
Full text linkThe bifacial photovoltaic (BPV) module is an emerging renewable technology that
produces augmented energy yield due to its capability of receiving sunlight both on the
front and rear sides. This contrasts with conventional monofacial PV, which captures
sunlight only on the front side. The extensive deployment of bifacial PV is expected to
reduce the cost of solar energy considerably. However, there is limited evidence
regarding the field performance of bifacial PV. Uncertainty exists in modelling the
ground-reflected irradiance received by the rear side of BPV, which depends on ground
albedo and the view factor (VF) from solar PV to the ground. Existing research on the
view factor considers infinite lengths of the PV array, which prevents accurate
determination of ground-reflected irradiance for PV arrays with finite lengths.
In this research, the finite element method (FEM) is used to develop a view factor
computation model for the finite length of the PV array. The model can be utilised to
analyse the ground-reflected irradiance at the rear side of bifacial PV, which is necessary
to predict bifacial PV's energy generation correctly, adding scientific value to this
research. The developed model is verified with the analytical solution with an error
margin of ±2%. The model is validated by comparing calculated and measured reflected
irradiance, which shows a strong agreement at a root mean square error (RMSE) of 16
W/m2
and a mean bias error (MBE) of 7 W/m2
.
An investigation into the performance of BPV for four ground surfaces: soil, white
pebbles, concrete, and white tiles is undertaken to quantify the gain BPV can achieve.
Six empirical models are developed based on the measured data, which can be utilized
to estimate rear irradiance gain, bifacial energy gain and power output. A probability
distribution of bifacial energy gain data at a 95% confidence level shows that the bifacial
energy gain varies within 2%-25% depending on the reflectance of the ground surface
and the probability is low that the bifacial energy gain will be more than 30%. Based on
the annual bifacial energy gain analysis, the highest gain range is found for white tiles
ground surface, followed by concrete and white pebbles. Simulations have been
performed for various utility-scale PV arrays across the UK to verify the reliability of
measured field data. The results are found to be consistent with the measured bifacial
energy gain which showed a clear agreement of about 2%-5%. The findings of this
research will remove some uncertainty about BPV performance, which is crucial to
predict its energy generation accurately
Building Occupant Environmental Behaviour (BOEB) model for LEED-certified buildings
Full text linkEnergy consumption in most residential buildings became a critical issue that should be
focused upon to move towards a green built environment and mitigate global warming.
Green agencies are actively practicing in different regions of the world while hoping to
achieve carbon emission reduction. Unfortunately, there is still a performance gap between
as-designed and actual energy consumption after operation. Occupant behaviour accounts as
one of the major reasons behind this significant uncertainty. Little is known about how the
occupants of these buildings cause the performance gap. This micro-focus has therefore
created a research opportunity to investigate in detail the LEED-certified building occupant
environmental behaviour to gain a better understanding on how to improve their behaviour
and the existing uncertainty in order to achieve potential energy savings.
The findings in this research rely on data collected from four LEED-certified buildings in the
UAE. The data analysis for the main research study was mix method including quantitative
(survey with 203 occupants) and qualitative (interview with 10 occupants and 5 operators).
After that the data was analysed using Structural Equation Modelling (SEM) technique to
investigate the interrelationship among three unobserved variables which are occupant
Attitude, Knowledge and Behaviour (AKB). The Building Occupant Environmental
Behaviour (BOEB) model was then developed. The development of the model was based on
the literature review and the best fitting structural model confirmed through SEM, together
with inclusion of motivational factors found in qualitative analysis in this study. Finally,
academic researchers and industry professionals in the UAE and Canada validated the
developed BOEB model in order to review the applicability of, and barriers to, this model.
Such model can be used by LEED policy makers, industry professionals, and governmental
authorities to promote better environmentally-friendly behaviour to potentially bridge part of
the existing energy performance gap
An integrated approach towards identification of the barriers to implementation of rooftop Rainwater Harvesting Systems in urban residential areas of Pakistan
Full text linkWater conservation in relation to rooftop Rainwater Harvesting Systems for urban residential areas is underdeveloped in Pakistan. Due to increased urbanisation, water availability in the domestic sector is stressed in terms of the quality and quantity of water resources. Rawalpindi the 4th largest city was selected as a case study for this research.
The purpose of this research was to assess the feasibility of implementing rooftop Rainwater Harvesting Systems for non-potable purposes in urban residential areas of Pakistan. The study included four focus areas; (i) A technical feasibility assessment of rooftop Rainwater Harvesting Systems in relation to annual/monthly rainfall data, current non-potable water demand and rooftop catchment., (ii) A questionnaire survey aimed at households in residential areas to identify socio-economic barriers/attitudes to rooftop Rainwater Harvesting Systems and (iii) Face to face interviews with policy-makers to identify the current policy implementation barriers regarding rooftop Rainwater Harvesting Systems.
In terms of data and results the study demonstrated that Rooftop Rainwater Harvesting Systems are technically feasible in urban residential areas of Rawalpindi in terms of roof catchment area and rainwater as a potential source of non-potable water. Household surveys showed that majority of the respondents were relatively unwilling to implement rooftop Rainwater Harvesting Systems. Major reasons for this included a lack of systems knowledge and awareness. In addition, concerns about water quality and maintenance presented significant barriers for respondents. Similarly, respondents reported that financial barriers were constraints to implementing rooftop Rainwater Harvesting Systems; large numbers of respondents were “very much willing” to install systems but only if local government provided incentives.
In terms of qualitative analysis, interviews with different stakeholders involved in policy formulation to policy implementation showed poor commitment and a lack of understanding and coordination. There were ambiguities in the process of policy formulation to the implementation of rooftop Rainwater Harvesting Systems; the policy process is complex and lacks a cohesive strategy. Last but not least poor monitoring and evaluation of the policy document were found to be barriers in the implementation of rooftop Rainwater Harvesting Systems
The integration of heat pipe technology into photovoltaic panels to increase the operational efficiency
Full text linkThe Sultanate of Oman growth in population and infrastructure expansion in recent years
resulted in increased energy consumption. As a solution to meet the increasing energy
demand, energy management strategies and renewable energy-driven technologies are the
most viable alternatives. Among these technologies solar photovoltaics (PV) are the most
promising technology due to the strong support from the Omani government. This study
introduces a Heat Pipe Heat Exchanger (HPHE) technology as a passive cooling mechanism
to be integrated within PV terminals. The aim of this research is to increase the energy
capacity of rooftop PV modules in hot and arid climates like the Sultanate of Oman. The
performance of the existing grid photovoltaic system was benchmarked using a thermal
collector and data loggers which monitored the PV modules temperature. The experimental
investigation resulted in the establishment of the site solar irradiation of 911.11 ± 143.43
W/m2
and the Nominal Operating Cell Temperature (NOCT) of 61.4 ℃ which produced
the Peak PV Power efficiency of 54.8 %. The recorded findings of 63.8 ℃ in the NOCT had
reduced the PV Power efficiency by 2.19%. The Computational Fluid Dynamics (CFD)
modelling of the HPHE using a single independent PV panel and its analysis was made using
different methodology of investigation to specify the optimum configuration. The CFD
modelling results were used to identify that the efficient physical set up is made of PV-HPHE-DSCD (Double Sided Condenser) orientation with screen mesh wick. The optimum
configuration was made of 20 units HPHE arranged on 50 mm on centers at an angle of
inclination of 3 degree in the middle installation of the PV back surface. Water was used as
a refrigerant with a fill ratio of 65% which equates to 59 ml loaded into the evaporator section.
The results of the final stage of the experimental set up had an average PV-HPHE power
performance of 29.03 ± 0.047 % and an average power generation of 71.94 ± 2.41 W that
comprised of 23.98 % of the rated PV power capacity. The validation of the CFD model
using experimental testing was carried out by determining the error which was found to be
within the accepted range with a mass flow rate of 2.07e-05 kg/s equivalent to an average
flow rate of 8.13 e-05 m/s (Al-Mabsali et al., 2021) in the evaporator to condenser flow
direction. The significance of the research data indicates that if the heat pipe technology is
incorporated in typical outdoor conditions and the power efficiency of the device can be
improved to a maximum of 7.94% from an average power efficiency of 5.09%
Solar PV generation enhancement using radiation augmentation from improved reflectance horizons
No full textThe total incident irradiation on a surface such as a photovoltaic (PV) module is the sum of beam, sky-diffuse and ground reflected radiation. Ground albedo or ground reflectance is defined as the ratio between the ground reflected radiation and the global incident radiation. A constant albedo value of 0.2 for bare ground and 0.5 for dry tropical localities is widely accepted and is used in the modelling of PV systems. The real albedo values of foreground surfaces are different and hence using a constant value may be unsuitable to accurately predict the output of PV systems. This research investigated the real albedo values of various foreground surfaces and how it is affected by the factors such as ageing, solar altitude, rain and cloud cover (sky conditions).
To investigate the impact of such factors, an experiment was setup to measure the albedo of conventional foreground materials (grass, sand and cement) and non-conventional materials (white pebbles, white paint, white tiles and aluminium foil). These materials were selected based on the type of PV applications such as solar farms and Building Applied Photovoltaic. The measured average albedo values of grass, sand, cement, white pebbles, white paint, white tiles and aluminium foil were 0.20, 0.36, 0.56, 0.15, 0.70, 0.61 and 0.73 respectively. Research has shown that non-conventional materials, increased the slope irradiation and ultimately the energy generation of PV modules. These results were further validated using the long-term data from the Garston and Edinburgh database. Lastly, a new computational tool was developed, which considers various albedo values of foreground materials simultaneously for any tilt angle of a PV module to compute the ground-reflected component
Optimal Subsidies for Increasing Two-Year and Four-Year College Graduation Rates
No full textIn 2015, the Texas Education Agency (TEA) in collaboration with the Texas Higher Education Coordinating Board (THECB) undertook an ambitious 60 30 TX plan as a part of its implementation of House Bill 22, introduced by the 85th Texas House of Representatives to enhance public school accountability. The 60 x30TX is a higher education plan that focuses on attaining a postsecondary graduation rate of 60% amongst the 25-34 age demographic in Texas by the year 2030. In this paper, I estimate the cost per high school graduate of attaining this target. I also compare the per student cost of this policy objective with that of two other counterfactual policies; the fi rst being one in which community colleges are made tuition-free for all high school graduates and the second being one in which public four-year college tuition is subsidized annually by 2,114 per student. I find that a 10,594. Finally, I fi nd that a conditional cash transfer of 3,640 for two-year and four-year college enrollment, respectively, attains the targeted postsecondary graduation rate of 60% by age 29 and costs 2.3 billion. This is far in excess of the THECB's FY2018 operating budget of $807million
The current state and future opportunities for fuel cell CHP in the UK residential sector : an evaluation of end-user perspective
Full text linkThe UK housing stock remains among the least efficient with the highest fuel poverty
rates in Europe. Besides, direct CO₂ emissions from buildings in the UK amounted to 83
million tonnes of CO₂ in 2017, from which 77% are from homes. Efficient and lowcarbon technologies have the potential to contribute to the alleviation of energy problems.
Also, the involvement of people affected by a problem in decision-making can encourage
sustainable energy transformations with reduced investment risks. Residential fuel cell
combined heat and power (CHP) energy systems have experienced significant uptake in
other countries such as Japan. This research evaluates these possibilities in the UK
context. The innovation-diffusion model by Rogers was used to analyse individuals’
adoption decision-making behaviour from the perspective of both current end-users and
potential end-users. For this purpose, a mixed-methods approach was adopted using an
online “public survey” (n=308), dealing with potential end-users, “qualitative semistructured interviews” (10 interviews), dealing with professionals, and “case studies” (4
case studies), dealing with current end-users.
The results confirmed the significance of typical variables of the diffusion of innovation
model, such as felt needs and problems, the relative advantage of technology, and the
novelty-seeking of individuals. It also confirms that activities take place in the
confirmation stage allow continued adoption. Issues that seem to impede the adoption of
fuel cell CHP in the residential sector in the UK relate to efficiency, performance and
safety. While other challenges relate to the high capital cost, availability of an intensive
mechanism and the large overall size of the system that must all be addressed in future
models of the technology. This study shows that there is scope for motivating individuals
to accept fuel cell CHP technology by communicating both individual and public benefits,
raising awareness with the use of demonstration projects and make information available
on trusted platforms to explain how users benefit from incentive schemes. Besides, in
future models and policymaking, several factors need to be considered, including the
willingness-to-pay no more than £1,000 over conventional energy systems’ capital cost
such as boilers, the availability of an incentive scheme similar to the pre-existed Feed-inTariff and the size of the system of no bigger than the washing machine. Besides,
recommendations are made about the way fuel cell CHP is presented to end-users and
whom to be targeted as early adopters.
The key contribution of this research is to offer a distinct evaluation of the current state
of fuel cell CHP in residential applications and forward-looking planning by providing
recommendations regarding future models of technology and its advertising behaviour in
a way that responds to the potential and current end-users’ needs. Recommendations for
future work are to explore the application of fuel cell CHP in housing associations and
community projects, to integrate fuel cell CHP into sales channels through power
companies, and to study the economics of the fuel cell CHP and make them available on
trusted platforms. The results can be of use to policy makers, designers and other
interested stakeholders
Energy efficiency retrofitting services supply chains: A review of evolving demands from housing policy
Full text linkAbstractAttention regarding the energy saving potential of existing houses has been occurring within the UK for a number of decades, producing an evolving landscape of policy mechanisms. Experience shows that innovative schemes are required, implemented at a large scale, to reach carbon reduction targets. In an unprecedented move within the UK, private industry was enlisted with the task of delivering the most recent domestic energy efficiency policy; the Green Deal (GD). This policy required the energy efficiency retrofit services (EERS) sector to increase capacity and deliver efficiency improvements to the UK's existing housing stock, at scale. This review evaluates this Green Deal policy landscape in relation to the requirement of EERS sector expansion. Previous UK retrofit policies act as comparative exemplars, to assess how policy is progressing in promoting private enterprises. Key findings suggest EERS expansion is most successful if policies are designed more holistically; UK policies show strategies which focus on simply the property and not the occupants have their disadvantages. Therefore, a move away from marginal financial incentives, such as the Green Deal's loan structure, to a wider consideration of how policy tools interact with supply chains and end users, would enable increased impact
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