How important energy waste and inefficiencies on energy consumption
Currently, the potential energy savings achievable through energy efficiency is much greater than the contribution from the use of any alternative source. We believe that in a scenario where the priorities be given to energy efficiency and the reduction of waste the global energy demand would be significantly less than the estimate, and only in this perspective renewables would bring a significant improvement in economic and environmental terms. We emphasize that this will still be a forced and without a quick turnaround we would be faced with short periods of energy blackout.
The energy efficiency is at the same time, to reduce emissions of greenhouse gases and to lengthen the maturity of hydrocarbon reserves, allowing seeking to have all the time necessary to develop technological solutions that we would need to take advantage of in a convenient and economical alternative energy sources. Even in Italy, energy efficiency can play an important role in addressing the challenge of energy and environment, as already happened in the past. The graph below shows the primary energy consumed in Italy in the last 35 years, and an estimate of the energy saved. The latter - referred to as "Negajoules" - is calculated on the basis of 1971 energy and represents the energy that every year you avoid consuming due to the fact that the Seventies are using less energy per unit of domestic product Gross. The energy intensity (the ratio of primary energy consumption and gross domestic product) is the most classic synthetic indicator of energy efficiency of a country, and reflects the state of the technology used as well as the energy behaviors of consumers.
The energy saved through energy efficiency, is already one of the main sources for our country, even in terms of the amount equivalent to the entire annual consumption of natural gas. The total energy savings that Italy has accumulated since 1971 is equivalent to the current annual consumption of oil the whole American continent, nearly 11 billion barrels.
In recent years, the process of reduction slowed in Italy is mainly due to the increase of energy consumption in some sectors, and it is still widely believed that much can be done in the future. Many factors influence the overall energy intensity of the economy of a nation. Very affect the requirements of a better overall standard of living and environmental conditions of temperature averages in the nation. It is not unusual for some particularly cold or hot, the demand for increased consumption of energy in homes and places of work, in order to heat the rooms (in an efficient manner through the pellet stove, heat pumps, or inefficient as the electric stove) or to refresh (inefficiently through air conditioners, or efficient through controlled ventilation). Usually a country with a high standard of living will have a greater predominance of these consumer goods and therefore will be much more energy-intensive than those with less than high standard of living.
Energy efficiency of buildings
The energy that is wasted each year because of inefficiencies in the facilities of houses and 'equal to the product of 7 from 730 MWe nuclear power plants. E 'and as' emerged from the report submitted by Cremonesi Consultations at the seminar promoted dall'Adiconsum on the theme 'Energy efficiency and renewable energy sources: balance and perspectives'. According to the study, therefore, the energy loss amounts to 15 million tons of oil equivalent per year. A waste which affects the energy bill: translated into EUR 16.3 billion euro share touches. In other words, only half '(49%) of the energy that is consumed in Italian homes becomes'' useful'', always explain the transaction, or used to illuminate, heat. (ANSA).
The reasoning more intuitive, based on statistics calculated as the majority of the world's energy consumption is due to domestic consumption, leads to suppose that the energy efficiency of a nation depends on the efficiency of its buildings (for the peculiarities of construction materials Basic accessories and methods of energy conservation, such as the orientation of the windows towards the sun, the low-energy lighting, efficient heating and thermal insulation), which are currently certified (energy certification of buildings.) Energy consumption buildings can be reduced significantly, as much as 50 to 60%, isolating the building's exterior walls and roof. The individual houses are the most subject to the loss of heat which "pass" through the shell (40 ÷ 50%), in condominiums the most critical elements are the vertical exterior wall through which is dispersed about 45 ÷ 50% of the heat.
Thermal insulation
The thermal insulation of a building can result in significant energy savings for both winter heating and summer cooling. A well-insulated building will also be a well insulated building, acoustically, thus contributing to the improvement of general well-being.
The heat loss of each element of the dwelling is measured by the coefficient of thermal transmittance or U-value The lower the U-value of an element (such as a window), the lower the thermal energy through the element itself.
However transmittance alone need for an analysis of static, that is, an analysis like the one winter when the internal heat for x months will be always higher than the outside temperature (hence the term static) while for the summer need a 'analysis dynamic type, in other words the day gets warmer out while outside at night will be cooler.
An 'Another concept to be considered in dynamic analysis is therefore to thermal inertia and phase shift of the thermal wave.
For example, in an old church in the summer will have a feeling of freshness and hygrometric comfort, due to the thermal inertia of the building structures that are able to counteract the natural transmigration from the hot to the cold face of the wall.
To achieve this you have to choose insulation with large heat storage capacity and make sure that the heat takes more than twelve hours to go from one side of the wall: wood fiber, cork, etc..
The correct calculation of the phase shift allows you to limit and / or eliminate the conditioning that is because of the black-out summer. In the U.S. it is estimated that there is an overabundance of power plants by 30% just to meet peak summer power demand for air conditioners. In Italy, the race to buy an air conditioner in summer would be totally nothing if you adopt these simple and basic rules of construction.
A major restructuring of the hedge and the facade is an excellent opportunity to redevelop the building from the energy point of view with a limited additional cost. The higher cost due to the inclusion of an insulating layer adapted pays for itself in less than 8 years. The future value of the investment will be strongly linked to the performance of the house. The value of a property without energy certification is expected to decrease over time. Among the energy efficiency measures as the insulation of the enclosure are the most cost effective because maintenance costs are virtually absent, and also to create the conditions for a significant improvement in comfort. Investing in thermal insulation means putting money into a virtual bank that produces a rate of return around 8%.
A good performance in the light of the current financial deals! A house that consumes less is a guarantee of greater economic security even in the case (very likely) that fuel costs would increase in the coming years.
The world production of oil and gas probably has already reached the peak of maximum extraction. As a result the supply of fossil fuels is declining and this is increasing inexorably the price of energy we consume in the face of growing demand, especially in Asian weights.
The combination of these factors is a problem now become a daily challenge faced when purchasing fuel.
In addition, isolating a building you can get interesting incentives that can help make it even more convenient each intervention (eg deductions of 55% laid down by the Financial Regulator). The D. Decree 311/06 makes it obligatory, in these cases, energy certification, which will be released at the end of work. Can then become very affordable energy efficiency improvements thermally and acoustically isolating the homes during renovations.
For these reasons it is necessary to create a campaign that would create in the public a culture of isolation and acoustic at 360 °, combining the advantages of saving energy through efficient thermal insulation of buildings to those of sound insulation, which takes us away from the noise of the city.
During the design phase, a qualified technician enabled, starting from an energy audit of the building, can be defined by the technically more convenient (choice of type of insulation, the choice of the optimum thickness of the insulation, the definition of the best technical solution, any modification of 'thermal plant, etc..). At the end of operation the obtaining of Certificate Energy is essential, in addition to being required to demonstrate the energetic quality of the building that is to certify that "consumes". Energy certification certainly will affect the market value of the property. Buildings more energy efficient, Class A, B or C (the energy classes are a total of 7, from A to G) will be more required because, other things being equal, will offer major benefits: they will be more sustainable for greater comfort, for the lower energy bill and less impact on the environment!
Energy production reaches its maximum efficiency in the combined use of multiple technologies in relation to geographic parameters, solar radiation (radiant energy), geothermal energy (enthalpy), wind (kinetic energy), biomass (chemical transformation).
Example: mix photovoltaic-thermal and geothermal
Photovoltaic
The energy produced will be used for the operation of geothermal heat pumps and for the Monthly utilities such as elevators and common illuminations, the excess enhanced through on-site exchange (Conto Energia)
Solar thermal
The solar thermal integration is significant both for the production of domestic hot water and for feeding the electrical appliances, both for the heating system at a low temperature in the intermediate seasons. The solar panels can be placed on canopies to shade the terraces and integrated in the structure. The solar contribution, the large surface area, high efficiency geothermal conjugated to allow the complete autonomy of the system at any time of year.
Geothermal
The presence of a layer of fresh water at a constant temperature of around 16 degrees C can make a design decision to opt for geothermal heat pump water / water with the withdrawal of ground water and re-injection of the same with a temperature difference of not more than to 3 degrees Celsius. With these devices a part of the electricity produced by the PV will be enough to power the heat pump.
Energy balance tending to draw
The mix above allows to produce the energy needed to balance the heat of the building. These performances are obtained with a design very careful, especially with regard to the sun, with the adoption of high-performance thermal insulation of external walls, roof and glass surfaces, and through the adoption of controlled ventilation systems for energy recovery.
23/01/2011
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Translated via software
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Source:
Italian version of ReteIngegneri.it