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[en] The author takes stock on the renewable energies available for a house, their advantages and efficiency. A special part is devoted to the heating (solar, wood and geothermal energy) and another to the electric power production and consumption. (A.L.B.)
[en] Coal-condensing power is marginal production in the deregulated Nordic power market and an increase in electricity consumption will therefore result in increased CO2 emissions. One goal of the Swedish energy policy is to reduce the amount of electricity used for heating in the building sector. This paper investigates the potential for reduction in electricity dependency and CO2 emissions from heating, taking the energy infrastructure into account, here defined as the capital stock of the buildings and heating systems together with geographical variations in heat intensity. In order to include the energy infrastructure in the analysis the study is made on a regional level (Southern Sweden) applying a comprehensive database describing the energy infrastructure of the region. The paper compares two scenarios for converting the heating systems of the region: one employing energy savings and with the aim to phase out the oil and most of the electricity used for heating purposes and a second which illustrates the effect if the current trend in the heating market continues. Both scenarios apply commercially available technologies only. From the second scenario it is seen that the current trend-contrary to the aim of the Swedish Governmental policy-shows an increase in electricity dependency for heating, mainly due to a large diffusion of heat pumps, but also due to installations of electrical floor heating and electricity heating systems installed in newly constructed one- and two-dwelling buildings. However, the options proposed in first scenario show that it is possible to reach significant reductions in the electricity dependency due to heating and in corresponding CO2 emissions. An analysis of the age structure of the heating systems shows that the transformation of the heating system is not completed until the year 2025, if new investments for replacement of heating systems are made only provided they have reached their economical life time, and only applying heating technologies which at present are known to be economically competitive. It can be concluded that future policies on transforming the energy system should be based on an analysis that takes the entire energy infrastructure (in this case of heating system) into account (e.g. not directed towards single technologies). More specifically for the region studied, which is considered representative for Sweden as a whole, policies should aim at installing heat pumps to replace electricity heating only in regions with low heat density where district heating is not competitive, in contrary to the present situation where heat pumps replace all types of heating systems
[en] In this study, in a floor heated room, natural convection heat transfer over the floor is analysed numerically for different thermal conditions. An equation relevant to Nusselt number over the floor has been obtained by using the numerical data. Different equations are given in the literature. They consider the effect of floor Rayleigh number while neglecting the effect of wall and ceiling thermal conditions. Numerical data obtained in this study show that the Nusselt number over the floor depends on not only the floor Rayleigh number but also the wall Rayleigh number (for insulated ceiling conditions). The equations given in the literature are different from each other due to their not considering the effect of wall and ceiling Rayleigh numbers. This difference between the equations may be eliminated by obtaining an equation containing the effect of floor, wall and ceiling Rayleigh numbers. In this new approach, an equation relevant to the floor Nusselt number that depends on the floor and wall Rayleigh numbers has been obtained in the floor heating system for insulated ceiling conditions. The equation obtained in this study has been compared with the equations given in the literature. It has been seen that the equation obtained in this study matches the numerical values under more extensive thermal conditions than the equations given in the literature. The maximum deviation for the equations given in the literature is 35%, but in the current study, the maximum deviation has been found to be 10%. As a result, it is more convenient to use the equation found in the new approach as a function of Rayleigh number over the floor and wall for insulated ceiling conditions
[en] Under the International Energy Agency Solar Heating and Cooling Programme, Task 24 Solar Procurement 5 countries co-operate (the Netherlands, Sweden, Canada, Switzerland and Denmark) on increased sale of solar heating plants i.a. by identifying buyer groups, joint calls for tenders and specification of requirements. The work is divided into 2 subtasks. Subtask A concerns the work connected with identifying buyer groups and starting sales and subtask B concerns the delivery of the necessary background material. Subtask B is managed by Denmark, which has been responsible for collecting and organising background material. This work started in 1998. From the beginning, the idea was to organise the background material in a book called 'The Book of Tools', but during the course of preparation it became obvious that it would be an advantage to place the material on the Internet. An initial version of the material has been finished in the winter 1999/2000 and has been incorporated in IEA's Task 24 homepage on the Internet address: www.ieatask24.org. The Internet home page is up-dated by the Canadian participants in IEA task 24. The target group is partly new potential buyer groups and current buyer groups and their advisors. It is possible to download the material for printing. (au)
[en] Thermal sensations of space, namely temperature, humidity and the movement of air, can be difficult to separate from other sensory information such as the sound of fans or ventilation equipment, or the smell of damp or cool fresh air. Despite this factor, efforts to reduce the consumption of energy through the installation of low-carbon technologies including sealed whole-building systems frequently isolate the thermal environment and fail to recognise and respond to the influence of other sensory information on personal preferences and behaviours. Older people represent an increasing proportion of the UK's population, can be faced with a range of physiological challenges associated with ageing, and sometimes have long-established personal preferences. Drawing from data collected across the Conditioning Demand Project, this paper explores the embodied nature of older people's experiences of low-carbon and more traditional thermal technologies in private residences, extra-care housing and residential care-homes, focussing specifically upon auditory and olfactory stimulus. Exploring the management of the sensory experience across these settings, we analyse each case to inform the development of new design and policy approaches to tackling housing for older people. In doing so, we further build connections between energy research and debates around sensory urbanism. -- Highlights: •Some thermal technologies present particular sensory issues and problems for older people. •Older people use a range of sensory stimuli in evaluating and controlling thermal environments. •Older people use non-thermal sensory information when selecting between thermal technologies. •Sensory information plays an important role in thermal technology maintenance
[en] A certificate system with an obligation to buying is a very relevant instrument in energy policy in order to stimulate the implementation of new renewable energy sources. This solution is widely supported; it is being institutionalized in many countries, especially in Europe and in the electricity sector, and the heating sector is soon to follow. This report discusses the broad lines of a possible green certificate system for the heating sector in Norway and concludes that it is might well be linked with a similar system for the electricity sector. For Norway, an isolated certificate system for the electricity sector would not be cost-effective. This is because this system would emphasize relatively expensive renewable electric energy rather than utilizing the large potential for replacing the electric heating of buildings with much cheaper renewable heat
[en] The purpose of this paper is to examine the lessons from the recent history of telecoms deregulation for electricity (and by implication heat) network regulation. We do this in the context of Ofgem's RPI-X-20 Review of energy regulation in the UK, which considers whether RPI-X-based price regulation is fit for purpose after over 20 years of operation in energy networks. We examine the deregulation of fixed line telecoms in the UK and the lessons which it seems to suggest. We then apply the lessons to electricity networks in the context of a possible increase in distributed generation directly connected to local distribution networks. We conclude that there is the possibility of more parallels over time and suggest several implications of this for the regulation of electricity and heat networks.
[en] Highlights: • Experimental research on heated/cooled radiant ceiling in the climatic chamber. • New values of radiant, convective and total heat transfer coefficients. • Coefficients required in dimensioning or scientific analyzes of radiant ceiling. • Comparison of heat transfer coefficients for radiant ceiling and for radiant floor. - Abstract: The heat transfer coefficients are very important parameters which are used to design and analyze the radiant heating/cooling systems in detail. However, in order to do this properly, the values of heat transfer coefficients should be estimated on the basis of heat/cold emitted to the room, rather than heat/cold supplied to the radiator. This article presents the experimental results of heat transfer coefficients for a heated/cooled radiant ceiling, which were estimated on the basis of heat/cold emitted to the room. The heat transfer coefficients were compared with the ones commonly used in the literature and the recommendations for improvements were provided. It was noticed that the values of heat transfer coefficients are overestimated, especially for the heated radiant ceiling. Attention was paid to the assumption of proper reference temperature depending on the mechanism of heat transfer. The comparison of heat transfer coefficients for the heated/cooled radiant ceiling and heated/cooled radiant floor was presented as well.
[en] People s perceptions of indoor air quality and thermal comfort are affected by air speed and temperature. We have extended the three-dimensional zonal model, ZAER, to be able to predict the temperature fields and the air distributions between and within rooms in the case of natural convection. This paper presents an application of the new zonal model dealing with the influence of a heated floor of one room upon the winter thermal comfort of an unconditioned Tunisian dwelling. Coupling ZAER with a thermal comfort model allows the assessment of the thermal quality of the dwelling through the prediction of a comfort indicator. The obtained results show that a heated floor can be a useful component to improve thermal comfort in the Tunisian context, even in another room
[en] In this work, medium capacity controlled heating system is designed and constructed. The programming method of control of heating process is achieved by means of integrated programmable logic controller (PLC) and frequency inverter (FI). The PLC main function is to determine the required temperatures levels and the related time intervals of the heating hold time in the furnace. FI is used to control the dynamic change of temperature between various operating points. The designed system shows the capability for full control of temperature from zero to maximum for any required range of time in case of increasing or decreasing the temperature. All variables of the system will be changed gradually until reaching their needed working points. An experimental study was performed to investigate the effect of tempering temperature and tempering time on hardness and fatigue resistance of 0.4% carbon steel. It was found that increasing tempering temperature above 550 deg. C or tempering time decreases the hardness of the material. It was also found that there is a maximum number of cycles to which the specimen can survive what ever the applied load was