Rational energy use

High energy efficiency and good indoor air quality

Efficient use of existing building systems and technologies provides maximum comfort at low energy cost. The quality-to-price ratio is achieved through proper analysis and combination of architecture and building systems. The use of computational software for building energy simulations is the best option for this.

Active systems

Effectiveness at low energy consumption

Heat pump systems

High efficiency and lower costs

Heat pump systems can supply heating, domestic hot water and cooling of a building. Powered by electricity, these systems are highly efficient and can supply heating or cooling energy at drastically lower price compared to standard heating appliances. There are several types of heat pumps.

Heat pump systems types

Installations for heating, cooling and domestic hot water

  • Heat pump "air"-"water"

    Option, which is most affordable. Investment for it is financially most advantageous. It is also independent of the existence of geothermal water or terrain properties, which makes it preferable and easy for installation and control.

  • Heat pump "ground"-"water"

    Closed geothermal system, which relies on the constant soil temperature after the second meter in depth and the heat exchange is performed by antifreeze, circulating in the ground loop (horizontal or vertical). Most effective type of heat pumps.

  • Heat pump "water"-"water"

    System, which uses geothermal energy. It is an open system that is directly supplied by a source of underground water with a constant temperature - drilling, well, drainage water, etc.

Ventilation systems

Smart heating, cooling and ventilation

Ventilation systems can be used for heating, cooling and ventilation to provide good indoor climate in terms of СО2, air age and air humidity. Modern systems are equipped with heat exchangers, allowing the exhaust air to transmit its energy to the incoming air, which provides significant energy savings in heating or cooling mode.

Solar shading systems

Energy efficient measure, allowing personal control

Solar shading systems should provide sun protection mostly during summer, when its energy is not needed for heating a building. They can be controlled by schedule, internal temperature, solar radiation on glass surface, etc.

Passive measures

Natural, free energy which can be used

In addition to the energy efficiency systems already listed (powered by electricity), it is also necessary to consider the passive measures (which do not require electrical energy) for heating, cooling and ventilation. Such may be:

  • Direct sun lignt (energy)

    Direct sunlight penetrates the premises during winter and reduces the need for additional heating during the day.

  • Thermal mass

    Thermal mass of the construction determines if it is possible energy to be accumulated which later can be released, contributing to energy savings from heating and cooling.

  • Orientation and building shape

    These factors are important for optimal use of solar energy in the winter. The closer to sqare the plan of the building is, the less energy it would needs for heating and cooling.

  • Solar shading building elements

    These are covers, balconies, blinds and other elements which are of such size, shape and location that allow the sun to penetrate during winter but protect from direct sunlight during summer, when the sun is high.

Combination of individual systems

Complementary solutions in construction

Effective use of energy is an objective that can only be achieved through complex solutions.

Combination of active and passive strategies is determined by energy design - computer analysis using software simulating the indoor climate and energy consumption of the building.

Strategies for design of one building

The importance of reasonable design

Quality construction takes into account environmental factors and eliminates those that have a negative impact. What is the meaning of an efficient heating and cooling system if supplied energy "leaves" the building through thermal bridges that had to be avoided at the design stage? Following principles is important to be taken into account:

  • Good insulation properties

    Good insulation properties of external building elements. Their U-value should be U ≤ 0.15 W/m²K. Current minimum requirements in Bulgaria are U = 0.28 W / m²K for walls, U = 0.40 W / m²K for floors and U = 0.25 W / m²K for roofs. Windows thermal transmittance coefficient should be ≤ 0.80 W/m²K (combined for glazing and frames) and glazing solar factor > 50%. Requirements in Bulgaria allow a thermal transmittance coefficient of U = 1.40 W / m²K.

  • Without thermal bridges

    Without thermal bridges in the construction of the building. In Bulgarian building regulations, excessive losses of thermal bridges are allowed, which is contrary to the principles of energy efficient construction. The term refers to heat conducting connections in the construction and façade of a building through which the heat "leaks" moving in the direction to the smallest thermal resistance. Example: Well-insulated external wall is intersected by a non-insulated reinforced concrete slab. In the contact zone, a thermal bridge is formed through which the inner surface is cooled, i.e. heat is lost, and in addition to heat losses, condensation conditions are created and consequently there is a risk of mold inside the room.

  • Air-tightness of the building envelope

    It is related to the inability of the outside air to infiltrate inside the building and vice versa. All the infiltration should be carried out by means of a ventilation system which allows its controlling, respectively controlling of heat losses.

  • Energy recovery from the building ventilation system

    A high percentage of energy recovered by the ventilation system - should be over 80%. The efficiency of fans in the ventilation system should also be with a value of near ≤ 0.5 W/m³/h.