In this article we intend to delve into the knowledge and necessary energy efficiency measures to be able to design an efficient building from the perspective of savings. We respond to what measures energy should be applied to the building and how apply the basic guidelines to obtain an adequate energy saving in buildings or homes.
A) REDUCE DEMAND ENERGY.
A.1.- IMPROVEMENTS TO THE ENVELOPE THERMAL . With them it is possible to reduce the losses or gains in energy from the home, so that in summer the flow of heat from the outside to the interior and in winter it avoids losing heat from the interior towards the outside, optimizing the behavior energy of the thermal envelope and managing to reduce energy demands for heating in winter, as well as for cooling in summer, these measures are as follows:
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– Winter: The heat does not leave the house, lower demand for heating.
– Summer: The heat does not enter the house, lower cooling demand.
A.1.1.-IMPROVING THE INSULATION THERMAL . If we focus on the measures energy saving insulation is a point important. Having thermal insulation panels in facades, roofs, false ceilings and floors when it comes to of horizontal elements on exterior space or premises not heated. In the case of the façade, the position of the same since when transdosing it externally it achieves that all the layers of the enclosure are within a temperature close to that of the indoor environment, notably improving thermal insulation, eliminating all thermal bridges and avoiding condensation, being not However, the most expensive solution due to the cost of the assembly of scaffolding and auxiliary means. The interior lining It is very economical but less recommended because it leaves areas with risk of condensation and thermal bridges. There is also the possibility of filling the air chambers with an insulator inside, this being an intermediate solution between both that also leaves thermal bridges. As for the type of insulation to place I would recommend those that They also have acoustic insulation properties extruded polystyrene, fiberglass, rock wool, foams made of polyurethane, ecological insulation made of insufflated cellulose in cameras and cellular glass that comes from recycling the glass and also has waterproof capacity.
A.1.2.-REPLACEMENT OF CARPENTRY AND GLASSES . So that carpentry is arranged with thermal break, double glazing systems with climalit-type air chamber, glass with a factor low solar or low emissivity with a treatment that achieves reflect much of the solar radiation they receive and therefore both significantly reduce the load that by solar radiation can enter the building. placement is recommended of roller shutter drawers with thermal insulation included and blinds with slats with insulation inside. Is It is also convenient to replace the carpentry with others with the adequate air permeability, depending on the climatic severity of the area where it is located, so that as established the Technical Code, for zones with greater severity (zones climatic conditions C, D and E) have lower permeability and are more watertight to achieve better thermal behavior.
A.1.3.-ADEQUATELY ISOLATE AREAS WITH THERMAL BRIDGES. That is, as in the enclosures, in areas where the enclosure is interrupted and loses its thermal inertia, the insulation must be reinforced, in shutter drawers, encounters with pillars, encounters with forged, and above all in those buildings in which to place radiators for heating, there was bad practice to make a niche under the windows reducing its thickness and leaving the enclosure thermally unprotected. Yeah possible, it is always convenient to place the insulation by outside the area where the thermal bridge is located.
A.2-IMPROVE THE VENTILATION CONDITIONS OF THE BUILDING AND SPACES UNDER ROOF. In In general, it is always advisable to carry out an adequate ventilation that guarantees indoor air quality. in zones warmer climates, this ventilation is even more important especially in summer, being convenient perform natural cross ventilation and night ventilation, so that it will achieve the loss of energy and dissipate the heat accumulated in the enclosures during the day, therefore It is advisable in old buildings in these areas to improve their envelope in order to improve its permeability and reduce its tightness, while in colder climates it should be act in reverse, decreasing permeability and increasing the tightness.
B) IMPROVING THE PERFORMANCE OF THE INSTALLATIONS OF HEATING, COOLING, DOMESTIC HOT WATER AND LIGHTING:
B.1.- REPLACEMENT OF THE EQUIPMENT OF THE INSTALLATION OF WATER HEATING AND DOMESTIC HOT WATER BY OTHERS OF GREATER PERFORMANCE. Substitution of boilers by other high-performance ones, such as boilers of condensation, biomass boilers or by a pump of air-water heat that exchanges heat with a circuit hydraulic, being more efficient the heating system by underfloor heating.
B.2.- REPLACEMENT OF AIR EQUIPMENT CONDITIONED BY OTHERS WITH GREATER PERFORMANCE . Most homes now have these. equipment, normally they are some type of heat pump for air conditioning, with an indoor Split and an outdoor unit, should be replaced by others with lower consumption and greater energy efficiency such as air-to-air heat pumps high efficiency.
B3.- IMPROVE THE DISTRIBUTION NETWORK OF HEATING AND DOMESTIC HOT WATER. In addition to insulating the pipes of the distribution network, the incorporate thermostatic valves in the radiators helps to reduce heat losses and to achieve a more efficient installation. It is also convenient that installation regulation and control equipment, such as switches, timers or thermostats are easily accessible and that they are programmed correctly.
B.4.- IMPROVING THE PERFORMANCE IN THE LIGHTING INSTALLATIONS AND OTHER EQUIPMENT ELECTRICAL . By replacing the lamps for other low consumption and high efficiency energy, and having control systems of lighting, other electrical consumption equipment and household appliances, it is convenient that they have a energy rating A or higher. Do not use stand-by mode electrical appliances and completely turn off electrical appliances when we are using them because they continue to consume energy
B.5.- ESTABLISH HOME AUTOMATION SYSTEMS TO CONTROL THE COMMISSIONING PERIODS ACCORDING TO THE OCCUPANCY SCHEDULES OF EACH AREA OF THE BUILDING AND IMPROVING THE MAINTENANCE OF THE FACILITIES. The introduction of home automation and automation especially if we had the case of a rehabilitation of a building intended for offices, they will allow us to get the most out of party and carry out a more efficient management of the thermal installations of the building, depending on the outdoor weather conditions and demand.
C) INSTALL RENEWABLE ENERGY. In In this case, the application of renewable energies such as solar thermal energy for the production of hot water or well photovoltaic solar energy for production of electricity, provided that due to the characteristics of the building and its facilities allow such implementation to be economically and technically feasible. If not Thus, it will be necessary to choose to implement systems with facilities and high energy efficiency equipment, as indicated in the previous point.
D) CHANGES IN THE HABITS OF THE USERS. It is very common for users to program heating or cooling at temperatures that are not only sometimes they are outside the parameters of thermal comfort, but which also entail a disproportionate increase in consumption energy, so that if we lower the temperature of our heating only 1°C, we can achieve savings between 5 and 10% energy and avoid 300kg of emissions of CO2 per household and year. About 20°C is enough to have a proper temperature. The thermostat must be programmed so that disconnect when we are not at home or keep a pleasant temperature, being able to achieve savings between 7 and 15% energy.
In the case of residential buildings existing multi-family, one of the most efficient proposals would be the implementation of solar thermal energy for water domestic hot and heating with high-speed heat pump energy efficiency along with measures to improve the thermal envelope (section A.1), so that with these measures simultaneously savings could be achieved energy that would oscillate between 70% and 80%, and a reduction of CO2 emissions between 40 and 60%. In this case, the maximum rating that could be achieved would be a B.
A) DESIGN OF THE BUILDING WITH PARAMETERS OF BIOCLIMATIC ARCHITECTURE. This means that, Since it is a building to be built, it must be designed and built under bioclimatic techniques that will provide optimal saving measures energy in the home , optimizing to the maximum a series of parameters that, depending on its location, its environment and climatic characteristics of the area, allow a optimal and adequate behavior of the same to achieve a greater energy efficiency and minimize the impact environment about their surroundings. It also aims to design the building to achieve passive heating in winter and passive cooling in summer, architectural techniques The most important bioclimatic are the following:
Two articles of interest for more information:
A.1.- LOCATION AND ORIENTATION OF THE BUILDING ACCORDING TO THE LOCAL CLIMATE. It must be adapted to the local climate. location of the area where it is located, since it determines its exposure to the sun and the winds, for this reason it is convenient to value both solar radiation, temperatures, relative humidity, rainfall and wind in both summer and winter. The topography, the vegetation of the place and possible sources of noise pollution in the proximities.
A.2.- SIMPLE AND COMPACT DESIGN OF THE BUILDING. A building of shape is required. compact, so as to reduce the surface of the envelope in relation to the volume of the building. casing surface lower thermal losses), since a excessive amount of projections or areas with viewpoints, would increase demand and energy cost. The form factor being the ratio between the surface area of the building and its volume. how much The smaller this is, the greater the capacity of the building to retain heat and therefore in cold climates it is convenient that this factor varies between 0.5 and 0.8, while for hot climates should be greater than 1.2. It is also convenient a adequate distribution of spaces, arranging to the north the less used areas such as garages.
A.3.-ADEQUATE DESIGN OF HOLLOWS ACCORDING TO ORIENTATION. Surface design glazed on each façade depending on its orientation, it is say according to the solar energy provided, recommending between 40%-60% on south façades, 10-15% on façade north, and less than 20% on the east, east and west façades. (See more in sunshine)
A.4.- THERMAL INERTIA OF THE ELEMENTS CONSTRUCTIONS OF THE ENVELOPE . in this way and with high inertia walls and floors we can soften the temperature variation between indoor and outdoor environments, achieving an adequate level of comfort.
A.5.-DESIGN THAT ALLOWS MAXIMUM REDUCTION OF THERMAL BRIDGES.
A.6.-CONSTRUCTION SYSTEMS AND MATERIALS THAT ALLOW REDUCTION OF ENERGY DEMAND. From way that they should be designed reinforcing their thermal insulation and its airtightness, certain systems being recommended like the following:
A.6.1.-ECOLOGICAL ROOFS LANDSCAPED . This system presents many advantages, both from an architectural point of view and aesthetic and environmental. Vegetation absorbs pollutants and produces oxygen with the consequent positive effect on the environment. It also improves the overall thermal insulation of the roof as well as its acoustic insulation, achieving help to achieve important conditions of comfort in the inside.
We can see more and access more than 20 manuals in the article roof gardens which also inquires into the benefits and drawbacks of this type of design.
A.6.2.-VEGETABLE FACADES. Being able to achieve a reduction of the solar contribution of up to 20%, through plant facades or planting a row of deciduous trees that help reduce the contribution of solar energy in summer and increase it in winter.
A.6.1.-VENTILATED FACADES . Made with ceramic or stone plates on a substructure of metal profiles, normally aluminum, leaving an air chamber that ventilates by natural convection with the main enclosure, through which it dissipates much of the energy absorbed by the outer shell. There are also similar integral solutions with panels solar thermal and photovoltaic integrated into the enclosure facade exterior.
A.6.3.-DOUBLE SKIN FACADES OF GLASS. This system is made up of two glazed surfaces, separated from each other by a chamber of continuously ventilated air, so that a second outer skin fixed to the wall by a system of anchors. With the object of being able to control solar radiation outside and reduce its thermal transmittance, these glasses are treated through a pigmentation or silk-screen printing process.
A.6.4.-GLASS WITH PROPERTIES SPECIAL. They can be glass with the addition of thin dynamic layers, chromogenic glasses capable of change its color or transparency or glass with camera with circulating fluids, in which the reduction of thermal loads It is obtained thanks to the circulation of a fluid through its chamber, since some of them are capable of absorbing part of the incident infrared radiation.
A.7.-PROTECTION ELEMENTS PASSIVE . To avoid excessive heating of some facades with a higher incidence of solar radiation in summer elements must be projected to control this radiation, being these overhangs, balconies, canopies, structures with mobile slatted elements adjustable, blinds, awnings, etc. They are measures of savings that do not give rise to a significant expense and provide efficient benefits .
A.8.-VENTILATION SYSTEMS PASSIVE. By executing solar chimneys next to Canadian wells to ensure the air renewal:
A.8.1.-SOLAR CHIMNEYS, are fireplaces designed so that the air inside is hot and rise by convection, so that when rising generates suction and causes a current of air, so that air enters from the Canadian well, thus ventilating the housing.
A.8.2.-THE WELLS CANADIANS , are a system that takes advantage of the geothermal energy of the soil so that, through buried tubes, to circulate the air through its interior way that in summer it acts keeping the environment cool (the ground is colder) and in winter warmer (the ground is warmer) benefiting the building efficient .
A.9.-. PASSIVE HEATING SYSTEMS WITH GLAZED GREENHOUSES AND TROMBE WALLS . The solar greenhouse consists of a glass enclosure attached to the house that uses the energy of the sun that accumulates in its interior due to the greenhouse effect, since radiation Solar enters but cannot leave heating the interior. The trombe walls are a solar collector formed by an enclosure glass exterior an air chamber and an enclosure of great thermal inertia, normally stone or concrete, where accumulates the energy of the sun so that through some perforations in the wall the air circulates by convention from the lower area to the upper one, entering the cold through the area bottom and coming out hot in the top to then distribute that heat inside the house.
A.10.-.WATER USE AND REUSE OF RAIN AND WATER SAVING MECHANISMS: From this way by means of a storage tank and equipment pumping system, rainwater is collected and used to irrigate plant species as well as for the home's own use when its use does not require it to be potable, also having mechanisms to save water in toilets and in urinals.
A.11.-WATER USE AND REUSE GREY. The waters that come from the washing machines, the sink and the shower can be reused for the toilet cistern, for which it is necessary to carry out an independent installation that collects this water and returns it to channel back into the toilet.
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A.12.-COLOR OF THE FACADE . Another aspect that intervenes in the exchange mechanism energy between the house and the outside, is the color of the facade. Light colors on the facade of a building facilitate the reflection of natural light and, therefore, They help repel the heat of insolation. Contrary to the dark colors facilitate solar capture. Although apparently not a matter of importance, the improve housing energy efficiency based on to color brings palpable and painless benefits to the pocket. (Learn more with architecture and color)
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B) HEATING, REFRIGERATION, WATER INSTALLATIONS HOT SANITARY AND EFFICIENT LIGHTING ENERGETICALLY . These facilities will be projected, designed and calculated to obtain its maximum performance, among these stand out the heat pumps air-to-air, air-to-water heat pumps and boilers high energy efficiency condensing (We can learn more in the inverter heat pump guide). It is highly recommended also project the centralized facilities, since that a higher performance is achieved than in the individual ones, as well as underfloor heating. Also the air conditioning VAV (variable air volume) and VRV (volume of variable refrigerant) guarantee good results.
C) INSTALL RENEWABLE ENERGY IN THE BUILDINGS: In this way, when planning and executing These facilities reduce energy consumption significantly, as well as reduce or even eliminate the CO2 emissions. The most used renewable energies in building are solar thermal energy, solar energy photovoltaic, biomass boilers for heating and water domestic hot water, water fireplaces, as well as other systems such as cogeneration or simultaneous production of heat and electricity in a single process.
In the case of new multi-family housing buildings, a one of the most efficient proposals would be the implementation of a biomass boiler for hot water production sanitary and heating, with high efficiency heat pump energy for cooling in summer (centralized two), simultaneously with bioclimatic design measures of section A, so that great energy savings and a reduction in CO2 emissions that could reach 100% obtaining the best rating energy, which is A.
In the face of a possible energy rehabilitation, it is recommended to carrying out a technical and economic feasibility study in which can be analyzed which is the solution or solutions whose implementation would help us to achieve deadlines shorter amortization. For this we will assess the cost derived from the implementation of the measures included in each proposed and the energy savings achieved annually for Calculate the required years of amortization. However, and taking into account the increase in the price of energy and the aid obtained based on the qualification achieved, These terms can be considerably reduced and therefore improve its economic viability.
ADVANTAGES AND FEASIBILITY OF ENERGY RENEWABLES IN BUILDING: WIND, SOLAR AND BIOMASS
As I indicated in my previous article, one of the three basic pillars to improve the energy efficiency of buildings consists of the implantation of the energies renewable sources that will provide us with effective measures saving energy , in this article I will make a description of these systems or installations that, together with the improvement of the envelope can lead us to achieve the maximum efficiency, lower consumption and reduction of emissions, above especially in those existing buildings that, for many years, They have been built without any sustainability criteria. As advantages of renewables harmonize perfectly so that they can be integrated with other systems or installations with maximum energy efficiency. The generation of solar and wind electricity can be implemented in parallel to the rest of the efficient facilities.
In addition, taking into account the point where the current regulatory framework on this issue, in which has approved the Royal Decree that allows self-consumption of the photovoltaic, and awaiting the approval of the Royal Decree Energy Certification of Existing Building, as well as that the State Housing Plan is also approved 2013-2016, it is clear that the main objective is oriented towards energy rehabilitation and efficiency improvement energy of these non-efficient buildings and homes energetically, so it is assumed that this will be the main engine capable of generating employment and reactivating the sector in the coming years.
In each particular case, the profitability and viability of the implementation of renewable energies will depend both on climatic factors of the place such as hours of sunshine, speed and direction of prevailing winds, the location of the building, the use and maintenance, etc, so that a assessment or study of these parameters to assess whether said implantation will be viable, studying the cost of the installation, what energy savings and what reduction of emissions are obtained and in what terms they can be amortized.
But without losing sight of the fact that it is not only a matter of savings economically, the main objective is, on the one hand, the reduction of emissions and impact on the environment environment due to the large number of buildings or dwellings existing with poor energy rating, and on the other hand the construction of new buildings with almost zero consumption design optimizing the design parameters to the maximum bioclimatic with clean energy. we would also get like this reduce the energy dependence of our country since we can and we have the necessary technology to function with clean energy. Some of the most renewable energies extended for use in buildings are the following:
1.-WIND POWER.
Spain is one of the leading countries as older wind energy producers around the world, which reflects the enormous potential of this energy, and therefore must can also be applied to buildings and houses as systems of production of electrical energy, as long as the conditions are favourable.
A wind power installation is basically made up of by a mill or a rotor with several blades that, when turning on the action of the wind starts an electrical generator, the which is usually attached to a mast. The main advantage of this energy is that, being renewable, it is inexhaustible, does not contaminate and In addition, its construction is subsidized by the state.
The great importance of the location of the building and the characteristics of the place that surround it, so that in general terms it will be more viable the greater the intensity of the wind, depending on the altitude, since the higher the altitude, the higher the speed, and also the terrain, with greater speed in plains or areas close to the sea. Therefore, better conditions will be given in buildings or isolated constructions, which are close to the sea, in areas high and when there are not a large number of obstacles in the Proximities that stop the wind.
The typical wind installation for buildings and homes is will proceed to the installation of systems through installations micro-wind, with compact wind generators capable of generate an electrical power of less than 100 kW, well insulated or in a hybrid system together with the solar installation photovoltaic. In this type of installation, a ideal place for which it is necessary to carry out a study of the wind speed, its feasibility will also be studied economy, analyzing costs and benefits generated, but there are to take into account that the improvement and technological advance allows for more efficient facilities and more cheap.
2.-SOLAR ENERGY.
2.1.-SOLAR THERMAL.
The main application of solar thermal energy is the production of domestic hot water for domestic use or industrial, heating of water in swimming pools, heating to low temperature with underfloor heating, and also for refrigeration through the use of absorption equipment. Usually is used on energy efficiency in single-family homes or buildings.
Solar thermal energy is mandatory in Spain since the entry into force of the Technical Code, requiring that at least a percentage of the total domestic hot water demand is produce through this system, said percentage according to the DB HE-4 and depending on the climatic zone, it varies between 30 and 70% in the general case and between 50 and 70% when the support energy source is through electricity.
COMPONENTS OF A SOLAR INSTALLATION THERMAL FOR A SINGLE FAMILY HOUSE:
The operation is based on harnessing the energy of the sun to heat water or other heat transfer fluid that circulates inside the collector, from this collector the water hot is transported by a primary circuit, so that heat is exchanged or stored in a reservoir for its subsequent use from the interior water installation hot to consumption points. The demand for water hot that we cannot produce through the collector in cloudy days, it will be generated by a heater or boiler supportive.
ADVANTAGES AND DISADVANTAGES INSTALLATION SOLAR:
DURABILITY AND AMORTIZATION OF THE INSTALLATION:
As previously mentioned, and taking into account that each particular case is different, but assuming a well-executed installation and proper maintenance it should have a long life of not less than 20 years. So the repayment term would be quite short, and can vary between 5 to 10 years.
2.2.-SOLAR PHOTOVOLTAIC.
Photovoltaic solar energy has as an application main generation of electricity from the energy from the sun using panels with semiconductor elements, usually silicon cells, This installation consists of a collector, a regulator, some energy storage batteries as well as a investor. There are two types of facilities isolated batteries that store energy in batteries to self-consumption and the systems connected to the network in which the Power is supplied to the electrical grid. The mounting of the panels can be made by integrating them with the slope of gables on roofs or façades always oriented to the south.
COMPONENTS AND SCHEMES OF A SOLAR INSTALLATION ISOLATED PHOTOVOLTAIC FOR A HOUSE:
1.-PHOTOVOLTAIC PANEL: It consists of a set of silicon cells, the most efficient are usually those of monocrystalline silicon, electrically connected, encapsulated (to protect them from the elements) and mounted on a support structure or frames. They provide in its connection output a direct voltage, and it is designed for specific values of tension that will define the tension to which the photovoltaic system will work.
2.-REGULATOR: Its objective is to avoid over charge the battery. In the charging phase during the day your mission is to guarantee an adequate charge in the accumulator, while in the discharge phase during the hours without light, is to allow adequate supply to the points of consumption without discharging the batteries.
3.-BATTERIES: Accumulate the electrical energy generated by plates during the day for later use when there is no sun They can be differentiated according to electrolyte used various types. lead-acid, Nickel-cadmium Ni-Cd, Nickel-metal hydride Ni-Mh or Lithium ion Li-ion. Also because of its technology that can be tubular stationary, starter, solar or gel.
4.-INVERTER: It is in charge of converting the current continuous current generated by solar panels alternating so that it can be used in the electrical network of home (220 V and a frequency of 50 Hz).
ADVANTAGES AND DISADVANTAGES OF ISOLATED INSTALLATION SELF-CONSUMPTION NETWORK:
DURABILITY AND AMORTIZATION OF THE INSTALLATION:
As a general rule, a photovoltaic installation for self-consumption usually has a useful life of at least 25 to 30 years, always clear assuming good use and maintenance; Regarding its amortization, there are several parameters that determine it, such as the quality of the installation components, proper installation, a calculation according to consumption needs, the use to which allocates the installation and even the subsidies that are can be obtained, but as indicative data it can be said that from 7 to 10 years can already be amortized installation for self-consumption, more than reasonable terms if its duration is taken into account.
3.-BIOMASS ENERGY.
The biomass energy uses as raw material the pellets, the remains of pruning, olive stones, the shells of almonds, (generally residues of agricultural activities and forest products or by-products of the transformation of the wood) to generate thermal energy for hot water sanitary and heating. There are also other types of biomass moisture from the manufacture of vegetable oils between which is the biofuels such as biodiesel or ethanol, which are especially efficient for boilers of cogeneration with Stirling-type technologies, but in this case I will refer to solid biomass.
In the case of single-family homes or buildings of homes, it is possible to obtain high energy savings and great efficiency with the implementation of biomass boilers, to generate heat for domestic hot water and heating.
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COMPONENTS AND DIAGRAM OF A BOILER INSTALLATION OF BIOMASS FOR ACS AND HEATING FOR A HOUSING:
It consists of the combustion chamber, exchange zone, ashtray and smoke box.
Feeding system by means of an endless screw.
ADVANTAGES AND DISADVANTAGES:
DURABILITY AND AMORTIZATION OF THE INSTALLATION:
Taking for granted the correct maintenance of the installation, its minimum durability should be between 20 to 25 years. The amortization depends on several factors, each case is different, but for example in the case of a house detached house of approximately 100 m2 with biomass for hot water and heating, can be amortized in a period Approximately between 5 and 8 years old.
A solution to carry out a project with maximum efficiency and with a high energy saving would be to install the boiler biomass with a geothermal heat pump for heating and air conditioning. Both in the case of residential buildings of new construction as for existing buildings, as well as for single family homes you can get maximum efficiency installing these boilers, as they reduce emissions to almost 100%, and provide significant energy savings, reaching the maximum energy rating.
Points of interest that can help us to improve the effectiveness of buildings :
I hope I have provided adequate information on
Article prepared by José Luis Morote Salmeron (Technical Architect – Energy Manager) Access to his website HERE, in collaboration with Home Repair Care
