Learning to live in a smart home

ABSTRACT

Smart homes promise to significantly enhance domestic comfort, convenience, security and leisure whilst simultaneously reducing energy use through optimized home energy management. Their ability to achieve these multiple aims rests fundamentally on how they are used by householders, yet very little is currently known about this topic. The few studies that have explored the use of smart homes have tended to focus on special-interest groups and be quite short-term. This paper reports on new in-depth qualitative data that explore the domestication of a range of smart home technologies in 10 households participating in a nine-month field trial. Four core themes emerge: (1) smart home technologies are both technically and socially disruptive; (2) smart homes require forms of adaptation and familiarization from householders that can limit their use; (3) learning to use smart home technologies is a demanding and time-consuming task for which there is currently very little support available; and (4) there is little evidence that smart home technologies will generate substantial energy savings and, indeed, there is a risk that they may generate forms of energy intensification. The paper concludes by discussing the implications of these findings for policy, design and further research.     

The shape of warmth: temperature profiles in living rooms

The most commonly used family of models in representing the UK building stock, BREDEM (the Building Research Establishment Domestic Energy Models), assume that all homes exhibit the same heating pattern and hence can be expected to have similar temperature profiles over the course of a day. The presented research shows that homes differ significantly in their respective temperature profile over the course of the day. A cluster analysis performed on temperature data from 275 living rooms in English homes over three winter months resulted in four different clusters of temperature profiles. The clusters differ significantly in their shape, as revealed by visual inspection, and supported by significant differences in minimum and maximum temperatures and temperature variability across the day. About 40% of homes showed a bimodal temperature pattern as assumed under BREDEM. However, the remaining 60% showed very different profiles. These findings challenge the assumption that one standard pattern fits all homes. Different temperature demand profiles have important implications for future peak power demands, particularly if domestic space heating is switched to electricity. It is also helpful for relating occupant demographics to appropriate forms of fabric retrofit.     

Energy use in non-domestic buildings: the UK government's new evidence base

Policy for reducing carbon emissions from non-domestic buildings in the UK relies at present on survey and modelling work carried out in the 1990s. The UK government's Department of Energy and Climate Change (DECC) is engaged in a programme of new research to update this evidence base. The work has two main components. The first is a database – the National Energy Efficiency Data framework (NEED) – in which floor area and activity data for non-domestic premises are being linked to electricity and gas consumption at the individual property level. The second is a research project of sample surveys designed to elicit information about buildings and energy use, but also opportunities for abatement and the behavioural and organizational factors affecting efficiency improvements. A pilot survey of the food and mixed retail sector has been carried out in advance of further surveys of the entire range of building types. The research programme is described along with some of the methodological problems it raises.     

An overview of domestic energy consumption in the UK: past,present and future

Global contribution from domestic sector towards energy use is quite remarkable, accounting for 20–40% of total primary energy consumption in developed countries. Current predictions indicate that the domestic energy consumption will steadily increase as a consequence of notable growth in world population, everlasting technological developments, growing demand for building services and rising comfort levels. In this respect, an accurate understanding and interpretation of energy consumption data in domestic sector is of vital importance for further amendments in energy policies at the global scale. Within the scope of this paper, an overview of the trends and some key drivers that have affected domestic energy consumption in the UK from 1970 to present is presented. Energy consumption by fuel type and end use, average domestic gas and electricity use in recent years, energy consumption per household and per person are illustrated in a comparable way.     

Second homes in Italy: every household’s dream or (un)profitable investments?

The use of a second home may result in different outcomes for households, ranging from financial profit and holiday use to uses that are clearly unprofitable. We contribute to the literature on second homes by exploring the case of second homes that are not let out, representing the least profitable outcome from an economic viewpoint. The empirical investigation relies on the 2002–2012 Bank of Italy Survey on Household Income and Wealth (SHIW), which also provides extensive information on property, including the actual use. Our results highlight: a gender gap, whereby the unprofitable use of second homes tends to be more clearly associated with male decision-makers; a lack of association with the economic characteristics of the household; and a strong association with the specific characteristics of the property, with inherited property more likely to be used unprofitably. In addition to casting doubt on the effectiveness of second homes as an investment vehicle, our results may have important policy or regulatory implications for housing and rental markets.     

Case study of zero energy house design in UK

Possible solutions for zero energy building design in UK are discussed in this paper. Simulation software (EnergyPlus and TRNSYS 16) are employed in this study, where EnergyPlus simulations are applied to enable facade design studies considering building materials, window sizes and orientations and TRNSYS is used for the investigation of the feasibility of zero energy houses with renewable electricity, solar hot water system and energy efficient heating systems under Cardiff weather conditions. Various design methods are compared and optimal design strategies for typical homes and energy systems are provided.     

Urban energy generation: Influence of micro-wind turbine output on electricity consumption in buildings

Small scale wind turbines installed within the built environment is classified as microgeneration technology. Such turbines may soon become a commercial reality in the UK as a result of both advancements in technology and new financial incentives provided by the government. In addition, microgeneration technologies, especially those with appreciable resource, have the potential to reduce built environment related CO₂ emissions coupled with reductions in consumers’ electricity costs. In many cases payback on capital investment is within the lifetime of the device. Micro-wind turbines installed in certain areas in the UK will fit within such criteria. The work presented here addresses modelling of such installations around the UK and presents a methodology to assess the suitability and the economic viability of micro-wind turbines for domestic dwellings. A modelling tool “μ-Wind” has been developed specifically for studying both energy yields and the payback periods for micro-wind turbines. μ-Wind predicts wind turbine performance prior to installation according to specific power curves either defined by turbine manufacturers or the user. Numerical consideration of wind speed data at specific UK sites was used to estimate energy yields and the results are projected to real electricity demand data from monitored dwellings in the UK. The results show that it is possible to predict with a good degree of accuracy the expected financial payback period for a typical domestic dwelling. Furthermore, the paper postulates that micro-wind technology could have the potential to make a significant impact upon domestic electricity generation when located at the windiest sites in the UK. The likelihood of a proliferation of these turbines in the urban or suburban environment is low but at coastal or inland high elevation sites the technology appears to have a promising future.     

浅谈低压电气系统节能技术的发展及趋势

本文首先介绍了国内外低压电气节能技术的发展历史,然后从变配电室、变压器、供电电缆、动力及照明等方面阐述了当前节能技术所采取的措施,最后对低压电气节能新技术进行了描述。     

Use and storage of domestic pesticides in the UK

Several epidemiological studies, particularly from the United States, have suggested health concerns may arise from the chronic exposure of young children to pesticides in their home environment. Most of these studies are retrospective and the available pesticide exposure information is either subject to the problem of recall or derived from surrogate information. Currently, little is known about the extent of pesticide use in homes and gardens in the UK. This was investigated in this study using a sample of parents from the Avon Longitudinal Study of Parents and Children (ALSPAC) cohort in and around Bristol. The level and extent of pesticide use by parents was explored through interviews that took place at the homes of the participants during August to November 2001, followed by an inventory of products stored in the home. From the results, 93% of parents had used at least one pesticide over the preceding year with the highest use being in the garden, second inside the home, followed by treating pets and head lice. Most households reported using one to five different products over the past year, with a mean of 3.5. The frequency of pesticide use showed that a minority of parents are using pesticides in the high frequency range. Over 85 different pesticide products were found to be stored in 76% of homes, with 76 different types of pesticide active ingredients. Insecticides were the most commonly used and stored pesticide.     

Domestic electricity use: A high-resolution energy demand model

The pattern of electricity use in an individual domestic dwelling is highly dependent upon the activities of the occupants and their associated use of electrical appliances. This paper presents a high-resolution model of domestic electricity use that is based upon a combination of patterns of active occupancy (i.e. when people are at home and awake), and daily activity profiles that characterise how people spend their time performing certain activities. One-min resolution synthetic electricity demand data is created through the simulation of appliance use; the model covers all major appliances commonly found in the domestic environment. In order to validate the model, electricity demand was recorded over the period of a year within 22 dwellings in the East Midlands, UK. A thorough quantitative comparison is made between the synthetic and measured data sets, showing them to have similar statistical characteristics. A freely downloadable example of the model is made available and may be configured to the particular requirements of users or incorporated into other models.     

Actual electricity savings and audit predictions for residential retrofit in the pacific northwest

An important and unresolved issue concerning home energy audit programs is the accuracy of the engineering calculations. That is, the accuracy of audit predictions of energy savings for recommended retrofit measures is generally unknown. Data available from a recent evaluation of the Bonneville Power Administration Residential Weatherization Pilot Program allow comparison and analysis of the relationships between actual electricity savings and audit estimates of likely savings.The BPA program offered free home energy audits to identify cost-effective conservation measures to reduce space and water heating electricity use. The program also offered zero-interest, deferred-payment loans for installation of measures recommended during the audit.The actual reduction in annual electricity use averaged 4130 kWh across participant households. The cost of the retrofits that yielded this saving averaged $2100. The median ratio of actual-to-estimated saving is 0.66. Thus, on average, two thirds of the expected saving is actually realized. However, there is substantial variation in this ratio. Actual electricity use increases in the second year for more than 10% of these homes. On the other hand, actual savings are more than double the audit estimates in more than 10% of the homes.     

Financial appraisal of wet mesophilic AD technology as a renewable energy and waste management technology

Anaerobic digestion (AD) has the potential to support diversion of organic waste from landfill and increase renewable energy production. However, diffusion of this technology has been uneven, with countries such as Germany and Sweden taking the lead, but limited diffusion in other countries such as the UK. In this context, this study explores the financial viability of AD in the UK to offer reasons why it has not been more widely used. This paper presents a model that calculates the Internal Rate of Return (IRR) on a twenty year investment in a 30,000 tonnes per annum wet mesophilic AD plant in the UK for the treatment of source separated organic waste, which is judged to be a suitable technology for the UK climate. The model evaluates the financial significance of the different alternative energy outputs from this AD plant and the resulting economic subsidies paid for renewable energy. Results show that renewable electricity and renewable heat sales supported by renewable electricity and renewable heat tariffs generates the greatest IRR (31.26%). All other uses of biogas generate an IRR in excess of 15%, and are judged to be a financially viable investment. Sensitivity analysis highlights the financial significance of: economic incentive payments and a waste management gate fee; and demonstrates that the fate of the digestate by-product is a source of financial uncertainty for AD investors.     

Estimating the Housing Wealth of Older Home Owners in Britain

Household surveys have recently started to collect data on the original purchase price of owner occupiers' homes. This provides a firmer basis for investigating the joint distribution of housing wealth, income and other personal characteristics than has hitherto existed. However, a number of difficulties arise which are discussed in this paper. A method is presented and validated, developed in the course of assessing the housing wealth of older home owners, for dealing with the specific problems associated with those who purchased their properties at discounted prices, whether through the Right to Buy or other routes. The method is based on data from the British Household Panel Survey, and subsequently applied to the UK Family Expenditure Survey to explore the housing wealth of older people. It also yields estimates of housing equity for younger people and can be implemented with other similar surveys.     

Smart technology in the home: time for more clarity

ABSTRACT

The idea of the smart home has been around for decades but smart homes (under most definitions) are extremely rare, although digital technology and automated appliances are commonplace in the more affluent regions of the world. This commentary argues that there are inherent difficulties with expectations for smart homes and with making them viable; and with definitions and roles of ‘users’ in smart systems. It considers what a smart home might be and the problems that smart homes might address, identifying two types of narrative in the smart-energy literature. One centres on the highly automated dwelling with integrated appliances, emphasizing state-of-the-art technology, convenience and, in some sense, efficiency. The second narrative type focuses more on system-level issues such as peak demand, ancillary services and the spread of microgeneration, and on selective applications of information and communication technology (ICT) to address these. Both raise questions about the identity of users, nature of control, boundaries of the home and ecological impact.     

A high-resolution domestic building occupancy model for energy demand simulations

Energy use in the home is a major source of carbon emissions and is highly dependent on the activities of the residents. More specifically, the timing of energy use, particularly electricity, is highly dependent on the timing of the occupants’ activities. Thus, in order to model domestic demand profiles with high temporal resolution, for example, in the context of designing and assessing demand side management systems (including the time-shifting of demand), it is of great benefit to take account of residents’ behaviour in terms of when they are likely to be using household appliances, lighting and heating. This paper presents a thorough and detailed method for generating realistic occupancy data for UK households, based upon surveyed time-use data describing what people do and when. The approach presented generates statistical occupancy time-series data at a ten-minute resolution and takes account of differences between weekdays and weekends. The model also indicates the number of occupants that are active within a house at a given time, which is important for example in order to model the sharing of energy use (shared use of appliances, etc.) The data from the model can be used as input to any domestic energy model that uses occupancy time-series as a base variable, or any other application that requires detailed occupancy data. The model has been implemented in Excel and is available for free download.     

Thermal building simulation using the UKCP09 probabilistic climate projections

This article investigates how to use UK probabilistic climate-change projections (UKCP09) in rigorous building energy analysis. Two office buildings (deep plan and shallow plan) are used as case studies to demonstrate the application of UKCP09. Three different methods for reducing the computational demands are explored: statistical reduction (Finkelstein-Schafer [F-S] statistics), simplification using degree-day theory and the use of metamodels. The first method, which is based on an established technique, can be used as reference because it provides the most accurate information. However, it is necessary to automatically choose weather files based on F-S statistic by using computer programming language because thousands of weather files created from UKCP09 weather generator need to be processed. A combination of the second (degree-day theory) and third method (metamodels) requires only a relatively small number of simulation runs, but still provides valuable information to further implement the uncertainty and sensitivity analyses. The article also demonstrates how grid computing can be used to speed up the calculation for many independent EnergyPlus models by harnessing the processing power of idle desktop computers.     

Policy implications for the performance gap of low-carbon building technologies

ABSTRACT

It is widely recognized that the actual impact of low-carbon technologies is often lower than predicted by models alone, a phenomenon which has been coined the ‘performance gap’. Despite this awareness, in many instances estimates of both energy savings and renewable energy generation in domestic buildings continue to rely on engineering models and building energy simulations rather than approaches that are based on measured parameters. Much of the existing literature on the performance gap focuses on energy efficiency and is concerned with the quantification of the scale of the performance gap. This paper adds to this body of evidence by drawing retrospectively on a range of grey literature evaluations of low-carbon technologies (including energy-efficiency measures, renewable heat and renewable electricity) in the UK household sector. The focus is on not only the quantification of the performance gap but also the qualitative factors often overlooked, such as installation issues or installer/user behaviour. Recommended policy changes include the development of evaluation standards, the experimentation with pay-for-performance programmes, ensuring that installation standards for low-carbon technologies are being enforced, and taking reasonable steps to ensuring that end users can use any new technology effectively.     

电冰箱替代工质及节能循环研究的动态及存在的问题

着重介绍了国内外关于电冰箱替代工质和节能循环方面的最新研究成果，并对我国在这一领域内的研究和实验工作提出了一些建议．     

企业供配电系统的节能监测与分析

随着我国经济的不断深化和发展,工业用电量占比节节攀高,然而,我国当前供配电技术与发达国家存在明显的差距,而且长期以来缺乏政策的引导,陈旧的用电设备无法得到及时更换,造成用电体系性能的整体下降。因此,推行工业节能监测,势在必行,这也是推动国家经济可持续发展的重要手段。     

Privacy,modesty, hospitality,and the design of Muslim homes: A literature review

Traditional Islamic teachings and traditions involve guidelines that have direct applications in the domestic sphere. The principles of privacy, modesty, and hospitality are central to these guidelines; each principle has a significant effect on the design of Muslim homes, as well as on the organization of space and domestic behaviors within each home. This paper reviews literature on the privacy, modesty, and hospitality within Muslim homes. Nineteen publications from 1986 to 2013 were selected and analyzed for content related to the meaning of privacy, modesty, and hospitality in Islam and the design of Muslim homes. Despite the commonly shared guidelines for observing privacy, modesty, and hospitality within each home, Muslims living in different countries are influenced by cultural factors that operate within their country of residence. These factors help to shape the architectural styles and use of space within Muslim homes in different ways. Awareness of the multifactorial nature of the influences on the Muslim perception of home and the use of space is necessary for architects, building designers, engineers, and builders to be properly equipped to meet the needs of clients.