31,482 research outputs found
Power and energy visualization for the micro-management of household electricity consumption
The paper describes a pilot system for the detailed management of domestic electricity consumption aimed at minimizing demand peaks and consumer cost. Management decisions are made both interactively by consumers themselves, and where practical, automatically by computer. These decisions are based on realtime pricing and availability information, as well as current and historic usage data. The benefits of the energy strategies implied by such a system are elaborated, showing the potential for significant peak demand reduction and slowing of the need for growth in generation capacity. An overview is provided of the component technologies and interaction methods we have designed, but the paper focuses on the communication of real-time information to the consumer through a combination of specific and ambient visualizations. There is a need for both overview information (eg how much power is being used right now; how much energy have we used so far today; what does it cost?) and information at the point-of-use (is it OK to turn this dryer on now, or should I wait until later?). To assist the design of these visualizations, a survey is underway aimed at establishing people's understanding of power and energy concepts
High resolution performance analysis of micro-trigeneration in an energy-efficient residential building
Trigeneration has long been proposed as a means to improve energy-efficiency for large and medium sized buildings. To curb increasing energy demand in the residential sector, researchers are now focusing their attention on adapting trigeneration to residential buildings. Literature is full of examples pertaining to the performance of trigeneration in large and medium sized commercial buildings, however little is known on the performance of micro-trigeneration inside residential buildings, particularly under a range of operating conditions. To understand the influence that parameters such as changes in thermal and electrical loading or different plant configurations have on the performance of micro-trigeneration, this research makes use of a detailed model of a Maltese apartment building, and associated micro-trigeneration system. The performance of the model is simulated using a whole building simulation tool run at high-resolution minute time frequency over a number of different operating conditions and scenarios. Each scenario was then assessed on the basis of the system's energetic, environmental and economic performance. The results show that, compared to separate generation the use of a residential micro-trigeneration system reduces primary energy consumption by about 40%, but also that the system's financial performance is highly susceptible to the operating conditions
Mitigating energy poverty: Potential contributions of combining PV and building thermal mass storage in low-income households
The issue of energy poverty has devastating implications for the society, and it has been aggravated in the past years due to the economic crisis and the increase of energy prices. Among the most affected are those with low incomes and living in inefficient buildings. Unfortunately, the bitter reality is that sometimes this part of the population are facing the next question: Heating, or eating? The declining prices of distributed energy technologies such as photovoltaics provides an opportunity for positive social change. Although their use does not address energy poverty directly, substantial contributions may be made.
Measurements of indoor temperatures in a social housing district of southern Spain in 2017 have revealed the unbearable temperatures that the occupants have to endure, both in summer and winter. Using this district as a case study, the present work aims to evaluate the benefits of exploiting its rooftop PV potential to cover part of the electricity consumption of the district (reducing the energy bills), and use the surplus electricity to supply power for the heat pumps in the district. Optimal alternatives regarding maximum PV production, maximum self-sufficiency ratio and minimum investment costs have been found, considering as well different options when sharing the available electricity surplus to improve the thermal comfort of the occupants. As far as the authors know, no previous study has followed an approach aimed at energy poverty alleviation such as the one presented in this work. The results show that using the surplus electricity to heat or cool the whole dwellings would improve the thermal comfort of the occupants in average up to 11% in winter and 26% in summer. If all the PV generation was used or more buildings in the area were employed to install PV modules, improvements up to 33% in winter and 67% in summer could be obtained, reducing at the same time the thermal comfort differences among the dwellings of the district
Solar-thermal and hybrid photovoltaic-thermal systems for renewable heating
Grantham Briefing Papers analyse climate change and environmental research linked to work at Imperial College London, setting it in the context of national and international policy and the future research agenda. This paper and other Grantham publications are available from: www.imperial.ac.uk/grantham/publicationsThis paper looks at the barriers and opportunities for the mass deployment of solar-thermal technologies and offers a vision for the future of solar-thermal systems.
HEADLINES:
-Heat constitutes about half of total global energy demand. Solar heat offers key advantages over other renewable sources for meeting this demand through distributed, integrated systems.
-Solar heat is a mature sustainable energy technology capable of mass deployment. There is significant scope for increasing the installed solar heat capacity in Europe. -Only a few European countries are close to reaching the EU target of 1 m2 of solar-thermal installations per person.
-One key challenge for the further development of the solar-thermal market arises from issues related to the intermittency of the solar resource, and the requirement for storage and/or backup systems. The former increases investment costs and limits adaptability.
-An analysis of EU countries with good market development, suggests that obligation schemes are the best policy option for maximising installations.
These do not present a direct cost to the public budget, and determine the growth of the local industry in the long term.
-Solar-thermal collectors can be combined with photovoltaic (PV) modules to produce hybrid PV-thermal (PV-T) collectors. These can deliver both heat and electricity simultaneously from the same installed area and at a higher overall efficiency compared to individual solar-thermal and PV panels installed separately. --Hybrid PV-T technology provides a particularly promising solution when roof space is limited or when heat and electricity are required at the same time.Preprin
It's About How and Where We Build: Connecting Energy and Smart Growth
In recent years, energy issues have become a growing concern for Americans. Largely missing from present energy discussions, however, is the role that land-use practices have on energy consumption and the use of alternative energy resources. By efficiently locating development, we can reduce the amount of energy needed for transportation and for other infrastructure as compared with spread-out, suburban development. Moreover, by including greater use of energy efficient design, these "smart growth" land-use practices could become even smarter -- and better achieve their goals of environmental protection, economic prosperity, and community livability. The smart growth land-use and energy efficiency movements are intrinsically linked, yet these two fields have mostly operated in separate worlds. Greater coordination between these two professions is warranted, yet substantial barriers exist. A recent survey reveals that planners' technical knowledge of energy issues is limited, as is their inclusion of energy factors in comprehensive planning, zoning, and development review. Heightened concern about foreign oil dependence, climate change, and the other ill effects of fossil fuel usage makes the energy-land-use collaboration especially important. Recently, there have been some hopeful signs of collaboration between energy professionals and community developers
Energy aspects and ventilation of food retail buildings
Worldwide the food system is responsible for 33% of greenhouse gas emissions. It is estimated that by 2050, the total food production should be 70% more than current food production levels. In the UK, food chain is responsible for around 18% of final energy use and 20% of GHG emissions. Estimates indicate that energy savings of the order of 50% are achievable in food chains by appropriate technology changes in food production, processing, packaging, transportation, and consumption. Ventilation and infiltration account for a significant percentage of the energy use in food retail (supermarkets) and catering facilities such as restaurants and drink outlets. In addition, environmental conditions to maintain indoor air quality and comfort for the users with minimum energy use for such buildings are of primary importance for the business owners and designers. In particular, supermarkets and restaurants present design and operational challenges because the heating ventilation and air-conditioning system has some unique and diverse conditions that it must handle. This paper presents current information on energy use in food retail and catering facilities and continues by focusing on the role of ventilation strategies in food retail supermarkets. It presents the results of current studies in the UK where operational low carbon supermarkets are predicted to save 66% of CO2 emissions compared to a base case store. It shows that low energy ventilation strategies ranging from improved envelope air-tightness, natural ventilation components, reduction of specific fan power, ventilative cooling, novel refrigeration systems using CO2 combined with ventilation heat recovery and storage with phase change materials can lead to significant savings with attractive investment return
Meeting Global Cooling Demand with Photovoltaics during the 21st Century
Space conditioning, and cooling in particular, is a key factor in human
productivity and well-being across the globe. During the 21st century, global
cooling demand is expected to grow significantly due to the increase in wealth
and population in sunny nations across the globe and the advance of global
warming. The same locations that see high demand for cooling are also ideal for
electricity generation via photovoltaics (PV). Despite the apparent synergy
between cooling demand and PV generation, the potential of the cooling sector
to sustain PV generation has not been assessed on a global scale. Here, we
perform a global assessment of increased PV electricity adoption enabled by the
residential cooling sector during the 21st century. Already today, utilizing PV
production for cooling could facilitate an additional installed PV capacity of
approximately 540 GW, more than the global PV capacity of today. Using
established scenarios of population and income growth, as well as accounting
for future global warming, we further project that the global residential
cooling sector could sustain an added PV capacity between 20-200 GW each year
for most of the 21st century, on par with the current global manufacturing
capacity of 100 GW. Furthermore, we find that without storage, PV could
directly power approximately 50% of cooling demand, and that this fraction is
set to increase from 49% to 56% during the 21st century, as cooling demand
grows in locations where PV and cooling have a higher synergy. With this
geographic shift in demand, the potential of distributed storage also grows. We
simulate that with a 1 m water-based latent thermal storage per household,
the fraction of cooling demand met with PV would increase from 55% to 70%
during the century. These results show that the synergy between cooling and PV
is notable and could significantly accelerate the growth of the global PV
industry
Changing demand: flexibility of energy practices in households with children (final report)
This report summarises the findings and recommendations from the âChanging Demand: Flexibility of energy practices in households with childrenâ research project funded by the Consumer Advocacy Panel. The project aimed to understand how households with children may be affected by electricity market reforms and demand management initiatives, such as cost-reflective pricing. The study involved 44 in-depth interviews, home tours and observations and a national survey with over 500 Australian households with children.
Overview
In households with children, many of the practices which use energy are coordinated and concentrated in the late afternoon and early evening on weekdays. Parentsâ reliance on routine to manage the demands of family life limits the flexibility of energy use. With limited ability to shift practices to other times of the day, and priorities such as âdoing whatâs best for childrenâ and âusing time efficientlyâ taking precedence, households with children risk financial disadvantage under pricing strategies such as Time-of-Use (TOU) pricing. Financial insecurity is widespread in, but not limited to, low-income and sole parent households. Health concerns, thermally inefficient housing and appliances, housing tenure, safety and noise concerns, and widespread tariff confusion also restrict the capacity of households with children to manage energy use and costs. Many parents had little time, interest or trust to investigate tariff choice and available energy information. As such, increasing choice and complexity in electricity market offerings does not meet the needs of these households and TOU pricing is unlikely to achieve its aims with this household group.
Family routines were more amenable to disruption on an occasional basis for non-financial reasons. For example, 85 per cent of survey respondents said they would reduce electricity use for a âpeak alertâ in hot weather. Acting for the âcommon goodâ appealed to most parents, for example to prevent an electricity outage and/or be part of a community effort. Household activities considered inflexible for a hypothetical TOU tariff, such as home cooling, television and computer activities and cooking, were considered. Recommendations from this study include reassessing the energy policy focus on price signals, tariff choice and information to address issues of household demand in Australia. Several alternatives are proposed such as peak alerts, and affordable access to public cooling during hot peak days. 
Meeting Global Cooling Demand with Photovoltaics during the 21st Century
Space conditioning, and cooling in particular, is a key factor in human
productivity and well-being across the globe. During the 21st century, global
cooling demand is expected to grow significantly due to the increase in wealth
and population in sunny nations across the globe and the advance of global
warming. The same locations that see high demand for cooling are also ideal for
electricity generation via photovoltaics (PV). Despite the apparent synergy
between cooling demand and PV generation, the potential of the cooling sector
to sustain PV generation has not been assessed on a global scale. Here, we
perform a global assessment of increased PV electricity adoption enabled by the
residential cooling sector during the 21st century. Already today, utilizing PV
production for cooling could facilitate an additional installed PV capacity of
approximately 540 GW, more than the global PV capacity of today. Using
established scenarios of population and income growth, as well as accounting
for future global warming, we further project that the global residential
cooling sector could sustain an added PV capacity between 20-200 GW each year
for most of the 21st century, on par with the current global manufacturing
capacity of 100 GW. Furthermore, we find that without storage, PV could
directly power approximately 50% of cooling demand, and that this fraction is
set to increase from 49% to 56% during the 21st century, as cooling demand
grows in locations where PV and cooling have a higher synergy. With this
geographic shift in demand, the potential of distributed storage also grows. We
simulate that with a 1 m water-based latent thermal storage per household,
the fraction of cooling demand met with PV would increase from 55% to 70%
during the century. These results show that the synergy between cooling and PV
is notable and could significantly accelerate the growth of the global PV
industry
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