renewable energy source which includes a number of products of plant origin (firewood, branches and wood waste from forestry, sawdust, bark and other residue from the wood industry, straw, maize, sunflower stalks, residues from pruning vines and olive trees), as well as products of animal origin (excrement and the remains of livestock, municipal and industrial … Continue reading "Biomass"
Number of air changes
a number which indicates the ratio between the volume of air entering the space in one hour and the total volume of space.
District heating
a system that includes a central preparation of heat energy in the heating plant, and its distribution to the end users – the meters
Heat pumps
compression devices that use the heat from the environment and turn it into useful heat for heating space and water with electricity
Chimney effect
a phenomenon which causes a flow of warmer air up through the building due to temperature differences, i.e. differences in density of warmer and colder air
Efficiency of the collector
represents the ratio of useful heat collected by the collector and the intensity of the incident solar radiation on the surface of the collector
Expansion tank
is used to retrieve the volume of the working fluid (hot water) in the heating system, developed due to warming
Energy building coefficient
all energy losses and gains of the building
Energy efficiency
the broad scope of activities which have the ultimate goal of reducing the consumption of all types of energy in a given facility, resulting in a reduction of CO2 emissions, without changing heat, light and other comforts of its occupants.
Energy audit of the building
analysis of energy consumption, the facade of the building and the energy system of the building to determine the efficacy and / or inefficiencies in energy consumption and to make conclusions and recommendations for improving energy efficiency
the body’s ability to perform work
Cooling factor
represents the ratio of the resulting cooling effect of the evaporator and brought power of the compressor
Fossil fuels
fuels that contain carbohydrates, formed from the remains of plants and / or animals. Currently, it is the main source of energy on Earth.  Energy from fossil fuels is typically released by combustion thereby releasing toxic and harmful gases that affect the environment (mainly affect the greenhouse effect) such as: carbon monoxide CO, carbon dioxide CO2, … Continue reading "Fossil fuels"
Photovoltaic cells
semiconductor devices that directly convert solar energy into electricity, and that can be used as a standalone or as an additional source of energy
Annual heat demand
Qh (kWh / year) – the calculated amount of heat necessary to be generated by the heating system during one year, to the building in order to maintain the internal project temperature of the building
Hydropower Plant
switchboards that, using water turbines, convert the potential energy of water into kinetic and mechanical that is later used to run an electric generator
Indicator of energy efficiency (energy code)
annual energy consumption of useful heated surface expressed in kWh / m² year
the flow of outside air into the room through the curtains on the windows and doors, and to a lesser extent, through the walls and the door during entering and exiting the facility
Infrared thermography
contactless and non-destructive method of recording the intensity of thermal radiation in the infrared range and display of temperature on the surface of the facade of the building
the amount of energy the Earth receives from the Sun’s rays
Inverter control
frequency regulation of a number of compressor turns, which achieves the effect of graded regulation (cooling devices)
part of the cooling system whose pipes evaporate refrigerant, during which heat for evaporation is taken from its environment
the process that leads to the oxidation of combustible components of a fuel, during which heat is released
a device for measuring heating and cooling of the energy
Air heater
device that uses waste heat from the condenser of a cooling device for the preparation of DHW
Air conditioning
a complex process that involves conditioning, transport and insertion of air into the conditioned space. Air-conditioning means preparing the air of certain temperature, humidity and cleanliness. The air is thereby put in place a certain speed in order to ensure airflow less than 0.25 m / s, in the zone occupied by people
Heat transfer coefficient U (W / m²K)
the amount of heat the construction element loses in 1 second per m² of area, by 1K difference in temperature
Thermal conductivity λ (W / mK)
the amount of heat that passes in unit time, through the layer of material surface of 1 m², a thickness of 1 m at the temperature difference of 1K. The value of the coefficient is different for various materials, depending on the density, size and connectivity of pores and the state of humidity of materials
Water vapor permeability coefficient (resistance to water vapor) μ
dimensionless quantity that indicates how many times is greater the resistance to water vapor diffusion, through the specific construction materials, than through a layer of still air of equal thickness and equal temperature
Cogeneration (CHP)
process of using fuel energy to produce two types of useful energy, one of which is thermal, and the other one electrical
Condensing boiler
boiler that exploits the heat of the fuel gas by increasing fuel efficiency
part of the cooling system whose pipes condense refrigerant, whereby the heat of condensation airs into the environment it operates in
in addition to radiation and heat conduction, it is one ways to exchange the heat. During the process of convection, heat is exchanged between the solid wall and fluid (liquid or gas) in movement, e.g. human body and the air in the space. The basic requirement for convection is another movement of particles hence the convection may … Continue reading "Convection"
Useful energy
energy that meets the needs of end users, such as heating electric hot plates on the stove
Local heating
the oldest form of heating where the heat source is located in a room that we heat (fireplaces, wood stoves, electric heaters, gas heaters)
designation for glass of reduced thermal transmittance due to metal-oxide coating on the side of glass towards the cavity
Mechanical ventilation
compulsory exchange of indoor air with the help of a fan
Split system
a cooling / heating air device, which consists of the outdoor unit in which the compressor and the condenser are located, and the indoor unit in which the evaporator and throttle valve are located
Greenhouse gases
gases which absorb infrared rays, natural or synthetic, which are in the atmosphere mainly due to emitting gases (e.g. by burning fossil fuels), and are partly formed by chemical reactions in the atmosphere
Degree day
The sum of the number of days of heating with the temperature difference between the agreed internal air temperature (20 ° C agreed) and the outside air temperature whereby only the days of the year in which the air temperature is lower than 10, 12 or 15 ° C are taken into account
The degree of action
the ratio of useful obtained work or power and expended work or power
a medium that allows the visual perception
Thermostatic valve
radiator valve that regulates the temperature of the room in a way that it controls the flow of heating water through the radiator
Ventilation pressure
insertion of outside air into the ventilated area
Thermal power plant
facility in which electricity is generated in a process of burning fossil fuels
Thermal comfort
state of mind with which we express satisfaction with the thermal  state of environment
Thermal insulation materials
material with a low value of the coefficient of thermal conductivity (less than 1 W / mK)
Heat gains of space
the amount of heat that enters a conditioned space from external sources (e.g. solar radiation) or the space from an internal source (e.g. metabolic gains due to people staying in a room, the heat released by lighting and electrical appliances) in a given time interval
Thermal bridge
smaller area in the coating of the heated section of the building, through which heat flow is increased due to the change of material, thickness or geometry of the construction part
The heat flow
represents the amount of heat transferred per unit time
Transmission heat losses
heat losses incurred by conducting heat through the facade of the building towards the environment and the soil, and towards the surrounding areas with different heat inputs as well
the process of water secretion from the surface of the human body in the form of water vapor
Trigeneration (or Polygeneration)
simultaneous production of electricity, heat and cooling energy
Effectiveness, efficiency
represents the ratio of the gained amount of heat or thermal flux and consumed amounts of heat or entered heat flow
the process of delivery and removal of air by natural or mechanical means to or from space
The ventilation heat losses
are due to the penetration of outside air through windows and doors
Wind generator
autonomous unit for the production of electricity from wind energy, which consists of a wind turbine and generator
Wind turbine
device for the production of electricity out of the kinetic energy of the wind
is, in addition to convection and heat conduction, one of the ways of heat exchange. During the process of radiation, heat is alternated by electromagnetic waves
Air permeability of buildings
Using a method of creating a negative pressure, the flow of air is measured through the structure, from the outside in, or vice versa