Generally horizontal galleries trimming the different layers of barren terrain and charcoal.

Sloping surface resulting from the holding, between the surface and a separation plane or between two separation planes. Note: A distinction can be made between face-to-face and face-to-face extraction.

Land of a rocky layer (in particular in a field) in such a way that the delimitation surfaces approach or are confused.

Angle formed by the line of greater slope of the surface of the slope and its projection on a horizontal plane. Is measured in degrees. The incline of the slope is the tangent of this angle.

Installation of reduced power for transformation of potential and kinetic energy of water into mechanical and electrical energy. As in large power plants, they can be divided into: - power stations (see Hydroelectric Power Station) - power stations (daily or weekly) (see Central de Regulação Diária Or Weekly)
- Hydroelectric Power Plants of Albufeira (see Hydroelectric Power Station of Albufeira)
- Hydropower Plants of Pumping Accumulation (see Hydropower Pumping Accumulation, Pumping and Turbine Installation).
Note: Generally, the denomination of small hydroelectric plants applies to those of few MW: minicentals those that reach a few hundred kW and microcentral ones with only an installed power of few kW. These limits vary from country to country.
Note: For the technical and economic classification of these small installations, the following should be taken into account: 2.1 The availability of water is uneven throughout the day or the season; This is a non-permanent energy rather than energy adapted to the needs of consumption, which is of prime importance in determining the value of the energy thus obtained. 2.2 Specific operating costs increase considerably as Installations are reduced.
2.3 For small plants to be cost-effective, great automation and special maintenance care are required. The degree of automation is an important decision criterion for the final profitability of the use.

Atmospheric pollutant emitted from natural and human processes, such as the burning of fossil fuels and various industrial processes. One of those responsible for the phenomenon of acid deposition.

Applicable to domestic customers with TUR rights and contracted power of less than 3kW, provided that the supply goes to the first housing, in which case it is applied automatically; And consumers: over 60 years of age; Unemployed; Belong to large families; Or who receive a minimum pension, in which case the granting of the social benefit depends on request and approval.

For customers who meet the requirements established in the Federal Government's "Low Income" Program, namely an average monthly consumption of less than 80 kWh in the last 12 months of consumption, or alternatively a monthly consumption of more than 80 kWh and less than 220 kWh, The client declares a per capita household income less than half the minimum wage.

Tariff applied to domestic customers whose contracting power is less than 3 KW. The fixed term is not billed, only if it bills the energy term.

Fare for consumption related to houses of permanent residence, even if they carry out a small professional activity, with a contracted power up to 2.3 kVA and an annual consumption not exceeding 400 kWh, according to the tariff regulation established by the Sector Regulatory Entity Energetic.

Set of architectural solutions that allow the collection, storage and distribution of incident solar energy on a building by the combined use of opaque and transparent walls, the thermal mass of the building, the natural circulation of the air, taking into account local climatic conditions (Passive systems).

Device for collecting incoming solar radiation to convert it, in general, into thermal energy to be transferred to a heat-carrying fluid.
Note: In some cases, the term collector may apply exclusively to the part receiving the solar radiation (absorbing surface).

Solar collector in which air is used as the heat-carrying fluid.

Solar collector in which a liquid is used as a heat-carrying fluid.
Note: In the case of a non-circulating liquid, it is called an accumulator. It could also be said solar collector with liquid.

Solar collector that does not use concentration devices. Note 1: This type of collector uses global solar radiation. Note 2: The main types of liquid collectors are: fluid slide collectors between two plates, fins collectors, roll bond collectors, etc.

Intensity of solar radiation outside the Earth's atmosphere per unit time and per unit area in a plane normal to radiation when the sun and earth are at their mean distance; Is considered to be 1367 W / m 2 (+/- 5 W / m 2 ).

Solar collector with or without concentration that allows the use of collected thermal energy to cook food.

Use of thermal energy of solar origin for the drying of agricultural or industrial products. Note: Outdoor drying is the most used. However, only one that involves an equipment can be considered as solar drying.

The vocabulary regarding solar energy has been deliberately limited in the light of practical considerations:
- Although the energies of wind, water, biomass, etc., are of solar origin, they are treated in other sections Because the technologies used to exploit them are specific.
- Primary (and even primordial), solar energy is a universal source of heat and light. However, the use of the term is limited to cases in which it is captured and exploited by devices adapted for this purpose, excluding its direct use. Rapid analysis of fundamental notions) since there are numerous works oriented to the physics and technology of the components.

Solar energy capture system that uses this to heat or preheat water intended primarily for domestic purposes (sanitary hot water).