One of the ways to take advantage of sunlight as for thousands of years is the production of passive solar energy. Passive solar energy is still a great unknown for the population. We tell you everything you need to know about this type of energy and the differences that exist with active energy, you can read the Solar energy definition to get into the subject.
Average household energy consumption has increased by 28% after the confinement suffered during the Covid-19 pandemic. We spend more time at home and energy consumption has skyrocketed in many homes where teleworking has been established to stay. Currently, we have the possibility of opting for renewable energies , which help us move towards a more ecological energy transition such as solar energy or other sources of non-polluting origin, helping us to achieve energy and economic savings in our electricity bill.
Production of passive solar energy
When we refer to solar energy, we must consider the existence of two operating models: passive and active energy . Normally, we are not able to differentiate these two terms and it is that Production of passive solar energy is still a great unknown of which the benefits that it can bring in the electrical consumption of the home are not known.
The increase in caring for the environment and the fight against climate change in recent years has been quite remarkable. This impact has set off alarms in the Spanish Government and the European Union, where measures are being taken to promote renewable and clean sources, leaving behind fossil fuels, such as coal or oil.
The European Union in its plan for the recovery of Europe, has already established actions to improve the energy efficiency of buildings, where newly built homes must be built in such a way that energy efficiency is high, producing practically all energy that will be consumed. This type of building is known by the nZEB nomenclature , that is to say, almost zero energy consumption buildings .
Spain has also established measures in line with the European line. In the Basic Energy Saving Document, a regulation belonging to the Technical Building Code, actions have been taken that will reduce the energy consumption of current buildings by 40% .
The new measures that have been taken by the institutions with respect to the construction of houses, are linked to passive solar energy and in the next article we will see why.
For this reason, we show you below what passive solar energy is, elements that compose it , benefits, how to take advantage of it and application examples for your home.
What is passive solar energy?
The passive solar energy directly uses the direct energy from the sun without transforming it . Therefore, they do not require any electrical device to carry out the transformation from one current to another and, where appropriate, for the accumulation of energy, as is the case with active energy.
How does this type of energy work?
The elements that make up the construction of passive buildings, that is, the walls and windows, are created in such a way that they take advantage of direct sunlight. These types of buildings are designed to fulfill two functions. One of them consists of the capture, storage and distribution of energy from the sun in heat during the winter season. The other function is to reject the heat that comes from the sun in summer. In this way, as much heat as possible in the home can be optimized .
If we want to make the most of the opportunities that passive solar energy offers us, we must take into account factors such as the region’s climate because temperature and solar radiation will be very influential when producing this type of energy . And not only can it be applied to new buildings, it can also be adapted to existing constructions, although the cost incurred will be higher.
Basic considerations of a passive solar design
Before carrying out any construction where a passive solar design is developed , it is necessary to know a series of basic considerations that will help us understand the operation in a more exhaustive way. Below, we list and explain those components involved:
- Window placement and type of glazing
- Thermal isolation
- Thermal mass
Window placement and type of glazing
The location of the windows in a home that uses passive solar energy is a very important aspect, as it happens in the same way in the orientation and inclination of solar panels where this factor plays a relevant role.
How is energy generated through the windows? Sunlight enters through the windows thanks to the glass that captures solar radiation , keeping the interior of the house warm. But, also, we must take into account the dimensions of the windows, installing the appropriate size and orienting them towards the south to equalize the gains and losses of heat without overheating, since they can obtain unwanted heat in summer and generate significant heat losses in winter. It is important to consider that during the winter seasons less heat is generated, approximately 5 hours. This balance of gains and losses can be sustained as long as the orientation of the windows is adequate and the perfect glazing has been chosen for its maintenance.
Normally, the windows should face south with an inclination of approximately 30º . If we locate the large windows to the south, we will obtain more solar energy for the interior of the house. However, north-facing homes must have windows with smaller dimensions since they are not capable of absorbing the same amount of solar energy as south-facing windows do.
The type of glazing is an equally important factor as the location of windows. We must avoid excessive glazing because it could cause a loss of energy, due to the small heating loads that originate in the new homes.
Thanks to the technological development of windows, the insulation properties have been improved that allow heat to be maintained in those areas of the house where it is necessary, avoiding unnecessary energy losses.
The thermal insulation is an essential factor in building passive solar design . It intervenes as an obstacle to the flow of heat, that is, it keeps the home warm by reducing heat loss in winter and reducing heat in summer so that our home remains in a cool and comfortable climate, thus supporting the high temperatures reached in this season. of the year. Said insulation must be carried out in all the components of the construction, both in windows, walls and even ceilings.
If we select a bad thermal insulation , the heat loss in the home could reach 25% -30% in winter , thus wasting the energy that we have generated.
Therefore, the better the insulation, the warmer our home will be. In more extreme climates, superior insulation should be provided and in good condition to avoid unnecessary heat leakage.
In order to avoid this loss of heat, it is convenient that most of the insulation is concentrated on the roof because it is the space where greater temperature control is required.
The thermal mass refers to the heat that is absorbed through walls, ceilings or floors made from elements that have the capacity to absorb solar energy on a large scale such as tiles, such that stored energy to use it for domestic use . On the contrary, to make the house colder in summer, this heat gain is reduced through installed projections or by making use of the blinds.
A good external ventilation installed on the roofs of the house will also allow the heat to dissipate inside, without concentrating on a specific area since the roof surface, being the most exposed to the sun, receives more solar radiation than the rest of construction elements.
To absorb a greater amount of energy, we can use materials such as brick, concrete or stone in constructions that will allow higher efficiency than other types of components. On the contrary, if we make constructions with not very robust or light materials such as wood, the thermal mass will be reduced and the amount of energy generated will also be reduced . Have you ever felt the heat given off by leaning on stones in the middle of nature? Well, the operation is similar to that carried out in a passive solar house because they capture all the possible energy and progressively release the heat that has been previously stored. The heat that is stored throughout the day is gradually distributed throughout the interior of the house to achieve a pleasant and comfortable temperature throughout the night.
We can say that the great advantage of thermal mass lies in the ability to maintain the right temperature , regardless of the season of the year in which we are. Its proper use will help us to get the most out of the passive solar system, turning our home into a more comfortable space and significantly reducing energy costs. Instead, a misuse of thermal mass could cause problems in more extreme climates, reducing our comfort and energy efficiency.
The shadow factor is also a component that greatly influences Production of passive solar energy. The shadows generated by the vegetation in the geographical area affect the solar radiation received, reducing the sunlight perceived in summer, being beneficial for the home. On the other hand, when we approach the winter seasons, the shadows will have a positive effect so that overheating does not occur.
The orientation of the house is a very important point to take into account so that the shadows that affect the building work correctly to perceive the correct passive solar energy and do not originate excesses that decrease efficiency. Window glazing should face south to avoid loads and overheating in winter.
Sun losses can become significant if the windows are continuously shaded without the possibility of recovering that energy again. How can we avoid this problem? We will only have to maintain a distance between the cornice and the top of the glazing of 50% or, if possible, 30% with respect to the height of the window.
Differences between active and passive solar energy
Solar energy has two ways of being used, through active energy, which is the best known since at this point photovoltaic and thermal energy are included, and through Production of passive solar energy .
There are several differences between both technologies, but the most important and characteristic is that active energy consists of a transformation of energies , converting the direct current generated by solar energy into alternating current available to use in all electrical appliances in our home. However, passive solar energy allows you to directly enjoy the energy produced by the sun without having entered any energy transformation process. And this, why is it? Thanks to the elements incorporated into the structure of the building, the energy from sunlight can be used more efficiently.
Once the main difference of both types of applications has been clear, we are going to list and detail the rest of the differences between active and passive solar energy :
- The active solar energy requires an electrical device that transforms current into alternating current so we can use solar energy generated by the solar panels. On the other hand, passive energy does not need additional equipment to carry out this transformation.
- To establish passive solar energy, a special design is necessary in the building, however, this is not necessary when we refer to active energy.
- The perceived solar radiation is captured through the different elements that make up the structure of the house, such as the walls, ceilings or windows. Instead, active energy absorbs solar energy through the solar panels of the system.
Of course, both are classified as 100% renewable energies that help reduce pollution, taking care of the environment and avoiding sources of polluting origin that destroy the planet.
Use of passive solar energy in the home
A good passive solar design of a home allows you to harness energy for different functions in the home . It is mainly used for lighting as well as for the production of hot water and heating. Thanks to the properties of the building, we will not need electrical devices to instantly enjoy the energy generated by the sun.
The materials belonging to the construction present distinctive characteristics that will achieve a uniform heat throughout the year, adapting to each season of the year. However, in areas where winter temperatures can be more extreme, passive energy will act in a complementary way to active energy to produce all the necessary energy that meets our consumption needs.
The use of passive solar energy allows:
- Reduction of spending on invoices
- Get the best comfort adapted to our needs
- Maintain the ideal temperature at all times by gradually spreading the heat throughout the house and taking advantage of the energy efficiency that this type of structure allows.
- Reduce dependence on external electrical energy and take greater advantage of natural light
In order to enjoy or take full advantage of passive solar energy, it is necessary that newly created houses contain the necessary elements to get the most out of it. This technology can also be used for existing homes, but it will be necessary to carry out a reform to incorporate the corresponding materials for its use, such as windows or walls. Also, the rest of the factors that we have explained above, such as the location of windows, the type of glazing or thermal insulation, must be taken into account.
In conclusion, we have seen that passive energy can be used both for heating and cooling the interior of the house , as well as for lighting that will lead to greater energy and economic savings.
Examples of use of passive solar energy
Production of passive solar energy has numerous applications for the home and, like active energy, they are inexhaustible and clean sources that we must take advantage of as much as possible and that provide us with benefits in many aspects.
Below, we have prepared a list of examples of how to use passive solar energy in your home:
- Heating by radiators or underfloor heating
- Hot water production
- Electric energy for domestic consumption: any type of electronic device
- Refrigeration devices such as air conditioning
- Hot water for swimming pools
Benefits of passive solar energy
A material designed to produce passive solar energy can achieve energy savings of 70%. In addition to this great advantage, we show you what are the main benefits that passive solar energy can bring us :
- Low maintenance cost . Since it does not have external equipment to take advantage of the energy, the maintenance required will be practically nil.
- It is a 100% renewable energy . It does not emit polluting gases and helps to maintain the environment, in addition to being an inexhaustible source that is the sun and we can always have it.
- Energy and economic saving .
- Reduction in the cost of electricity and gas bills .
- Compatible with solar panel installations . In fact, it is currently considered as a complementary technology.
Currently, passive solar energy remains in continuous development to improve its technology and offer its maximum potential for consumption in our homes. It is a technology that coexists with active solar energy and is increasingly being implemented in buildings and offices.
It is true that it requires a significant initial investment due to the incorporation of certain components in the building, but the amortization period will be reduced compared to what it can provide, achieving significant energy and economic savings. In addition, the maintenance cost is reduced since all the elements are in the structure of the house itself and it does not require external equipment for its operation.
The use of Production of passive solar energy will improve energy efficiency and achieve greater economic savings, always respecting the environment. That said, there will be many homes whose adaptation to Production of passive solar energy, by location or characteristics, is complicated, for them the option of photovoltaic panels is a great option to continue taking advantage of the sun’s potential to operate your home. At Otovo, we can help you study the best facilities for your home.
Passive methods of obtaining solar energy
Passive systems used in construction allow the use of solar energy without using additional energy from outside. It is possible to passively heat, cool and store heat in buildings, while we mainly deal with heating. It is a system that reduces the amount of energy required to ensure a sufficiently high temperature in the rooms.
Reducing the energy requirement to heat a building is the main objective of passive systems. With the use of innovative materials, construction and installation solutions, it is possible to reduce heat demand and even achieve energy self-sufficiency. Passive solutions not only improve the thermal balance of buildings, they also affect their appearance, creating highly aesthetic and functional solutions. Production of passive solar energy is a term that refers to the use of solar radiation that does not require any action on the part of the user.
What is the main objective of passive solar energy systems?
The main objective of using passive systems is to reduce the demand for energy to heat the building. By using innovative construction and installation solutions with the simultaneous use of modern materials, we can not only reduce this demand, but even ensure energy self-sufficiency. Said construction provides, in addition to functionality, also an aesthetic aspect of the building. The systems of passive use of solar energy guarantee the full satisfaction of the energy needs of residents solely from solar radiation, without the need to use other forms of heating, although, if necessary, it is possible to use other techniques, for example, a floor heat exchanger. .
The use of solar energy is possible thanks to the adequate conformation of the body of the building, installed glazing and construction elements properly placed in relation to the position of the sun in the annual and daily cycle. As already mentioned, it is possible to use alternative heating techniques. Shading structures and elements are also important in order not to overheat the interior and thus significantly reduce the thermal comfort of residents.
The solution between direct and indirect solar gain is the Balcomba system. The highlight is the fully glazed porch located on the south side. The heated room is separated from it by a massive wall, the task of which is to store energy. The veranda is directly heated and is characterized by large temperature fluctuations. The living space, in turn, obtains solar energy indirectly. It is a structure that is readily used in our climate zone, also in the case of thermal modernization of existing buildings.
The advantages of such construction are the reduction of economic outlays and the reduction of energy demand. A house made on a passive heating system, which also meets the passive house standard, does not require a traditional heating installation, which significantly reduces its construction costs, partially offsetting the additional expenses for its construction. Passive heating techniques are also indispensable when erecting a self-contained building. However, the disadvantage is that the effective use of such systems is only possible in construction with a small unit energy demand for heating. Another disadvantage in this case is the need to use a traditional heating system with low inertia. All this indicates that they are ideal solutions for energy efficient buildings.
Passive systems can be divided into two basic types:
- direct profit system
- indirect benefit system
Direct profit system
changes in indoor temperature can cause thermal discomfort to residents due to the acute nature of the fluctuations. This effect can be mitigated through the use of shading structures and solutions (eg roller blinds or awnings) or completely avoided through the use of indirect systems. They allow changing the period of solar energy supply to the room at later hours.
The direct benefit system is the simplest passive heating system. The fully glazed south wall of the room allows solar radiation to penetrate inside, where it is absorbed and stored. The stored energy is partially transferred to the air inside the building, causing its temperature to rise. The hood is an inseparable element of this installation. Its function is to prevent overheating of rooms in summer and not an obstacle to solar radiation in winter.
Indirect benefit system
isolates the interior of the building from direct sunlight. One of the solutions is called the Trombe wall, that is, a solid structure, also protected from the outside with glass. Thanks to the ventilation space between these elements, it is possible to transfer the heat gains to the room. Solar radiation that passes through the glass liners is absorbed by the accumulated dark surface of the wall, causing its temperature to rise. After opening the channels that connect the heated room with the space between the glass and the wall, air can flow through the space (the effect of different air densities in the space and the room).
The cold air is sucked in through the lower channel and returns to the upper room after being heated in the slot. This provides a phase change with respect to the activity of the sun. On the other hand, closing and opening the ventilation ducts allows you to regulate the room temperature during daylight hours. An additional advantage of such a structure is the possibility of using it for air conditioning purposes in the summer.
We have reached the end of the article Production of passive solar energy, I hope the concepts have been understood and I thank you for visiting my website.