A building project can be regarded as sustainable only when all the various dimensions of sustainability (environmental, economic, social, and cultural) are dealt with. The various sustainability issues are interwoven, and the interaction of a building with its surroundings is also important. The environmental issues share, in common, concerns which involve the reduction of the use of non-renewable materials and water, and the reduction of emissions, wastes, and pollutants.

The most relevant building elements contributing to its energy efficiency and to sustainability are its systems. The key innovative element of EE-HIGHRISE is the integration of building envelope solution, HVAC system,  intelligent control center (ICC) and RES resulting in passive standard for a high rise building of 11 storeys with 128 apartments while still being cost effective. A number of systems have been implemented in ESH. See the details bellow for the following sustanible building systems:


  • Heating and hot water heating
  • Ventilation and air conditioning
  • Shading
  • Electrical energy
  • PV system on the roof
  • Lighting
  • Building intelligent control centre and services
  • Building envelope
  • Windows
  • Air permeability and moisture management
  • Water and waste water management
  • Waste management
  • Green roof
  • Rain water harvesting / collecting
  • Building equipment
  • Materials and solutions
  • Charging points for electric vehicles
  • Alarm / technical security

    Heating and hot water heating

    The building is connected to the district heating network system Energetika Ljubljana with temperature regime 110/60°C. House heating station is installed in the basement of the building and provides heat power for individual residential heating substations. Another heating station provides heating power for commercial part of the building. Temperature of hot water for heating is regulated by electrical system that calculates required water temperature in dependence of the outside temperature. Temperature regime in secondary side of heat station is 75°/55°C, so for apartments sub-stations as for commercial part of the building. Residential heating substations (STP) with power of 35 kW, 50 kW and 65 kW, depending on the size of each dwelling, is used for heating and preparation of domestic hot water (via the built-in heat exchanger STP). STP are build-in type and is located in the individual apartment. A built-in ultrasonic heat meter (calorimeter) with M-Bus interface is mounted on to the return line of STP. Measured power consumption in the individual substation is send via the M-Bus interface to a common accounting system.

    Termix VMTD-F

      Picture: Termix VMTD-F (Danfoss commercial leaflet, accessible on heating.danfoss.com)

    Heat distribution elements for apartment rooms are going to be radiators and floor convectors. Heat provided for individual room is going to be controlled by the apartment central regulation system which regulates room temperature according to project demands and user requirements – can be controlled via graphical user interface (GUI)

    Described system provides the best solution for user friendly individual heat consumption. Its local regulation is the most optimal way of transparent and fair heat distribution for high-rise building.

    Danfoss technical paper

      Picture: Danfoss technical paper ˝Controls Providing Flexibility for the Consumer Increase Comfort and Save Energy˝, Mr. Halldor Kristjansson, Danfoss A/S, published in HOT|COOL l/2008, DBDH (www.dbdh.dk)

    Justification of the chosen energy source and the system for heating and sanitary water (explanation for criterion 25% energy from RES – renewable energy sources). Source of energy for heating and sanitary water is district heating, suplied by Energetika Ljubljana. It's a clean, reliable and cheap energy source for heating and sanitary water throughout the whole year. The heating and rational continuous preparation of the hot water are provided with apartment heat stations. Planned annual energy consumption is 129MWh for heating and 270 MWh for hot water. The share of RES in district heating is 7,3% which presents 29MWh for the planned use of 399MWh (source: Energetika Ljubljana, data is for 2010)

    The dilemma between floor heating and radiators: the calculation of the implementation, the dilemmas as damages during the implementation and reparation. 

    Ventilation and air conditioning


    Small apartments with a single living space – studios are ventilated by a wall mounted compact heat recovery unit (HRU) with a simple through-wall duct for supply and one for exhaust without additional duct system (Brink Advance). Discarded air is extracted by bathroom ventilator and send through vertical air duct to the roof exhaust. Living space is cooled by simple wall mounted split air conditioning system.  

    Ventilation and cooling system in studio apartments

    Picture: Ventilation and cooling system in studio apartments (source: Remty-R d.o.o.)

    One storey apartments

    One storey apartments have a central ventilating system, with distribution of fresh air to each living and sleeping room and exhaust from kitchen and bathrooms. Air ducts are installed in to double ceiling and end with air grille or air valve. HRU (Brink Renovent HR Medium) is placed in the dedicated cabinet and connected with vertical ducts that provide fresh and lead out discarded air. Joined air intake is situated on the mezzanine floor and air outlet is on the roof. Cooling of the apartments is done by heat exchanger built in the supply air duct and by optional wall mounted air conditioning unit (like in studios). In most cases (moderate summer temperatures) the cooling with duct heat exchanger and recuperation will suffice to maintain comfort zone values of temperature and humidity. For higher comfort and more flexibility (faster cool down of overheated apartment or temperatures, lower than usually required in high summer time) optional wall mounted unit can be installed in the pre-prepared place (living room or central hallway). Both heat exchangers can be connected with the same outside compressor unit (twin air conditioning split system).  

    Ventilation and cooling system in one storey apartments

    Picture: Ventilation and cooling system in one storey apartments (source Remty-R d.o.o.):

    Two storey apartments

    Ventilation and cooling system in two storey apartments is designed similarly to the one in one story apartment. The biggest difference is in the size of distribution system (HRU with higher volume flow is installed - Brink Renovent HR Large). Also the wall mounted air conditioning unit is already installed in the original system (it is not optional anymore). The air duct distribution system is installed in the floor of upper storey. Air supply for rooms is provided by floor and ceiling air grilles and exhaust by ceiling and wall air valves.   

    Ventilation and air conditioning system in two storey apartments

    Picture: Ventilation and air conditioning system in two storey apartments (source: Remty-R d.o.o.)

    heat station recuperator1  heat station recuperator2

    Pictures: Actual implementation of the heat station and electrical installation; and of recuperation and cooling unit in the apartment

    Moisture management

    Relative humidity is not regulated directly, at least the installed system do not provide systematic control of the whole apartment. But humidity can be controlled indirectly by amplifying rate of ventilation or by dehumidifying air with cooling (in summer) by wall mounted or duct indoor air conditioning unit. There is also no possibility to moisturize air except by local humidifiers (not included in installed system). All presented functions can be controlled manually (there is no automatic function) or by a timer via GUI (graphical user interface). That means that moisture management could be done by advanced user control. Dehumidifying potential will mostly be welcome during summer when high humidity in combination with high temperature causes discomfort and possibly mould. But the same system function could become a problem in winter when cold air from outside is heated by recuperation and heating system, so its relative humidity drops often below the value in comfort zone. In those cases the use of local humidifiers is recommended. Comfort zone according to DIN 1946 is marked green on the presented chart. It represents desired living conditions inside the house with a temperature from 20°C up to 26°C and relative humidity in between 30% and 65%.

    Molir-h-x-Diagram for air humid

     Broad range of environmental conditions (marked with green line) typical for Slovenia (in contrast with northern Europe) contributes to complexity and expensiveness when comes to complete air conditioning system design. That is why this problem is not fully addressed in Eco Silver House, but provided system still has some level of control that benefits user. 


    Automated external blinds - key characteristics:

    • solar gains in winter and shading in the summer
    • automatic operation depending on the solar radiation and seasons of the year / managed by ICC
    • controling of the shades
    • automatically and manually through ICC


    Electrical energy

     District heating was chosen so that precious electricity wouldn't be used for the heat pump. That way we can significantly reduce the electric connector's power input of the building and reduce regulary burdens of the electric network consumption. Electric energy is too valuable to be used for thermal energy, if one is available from the local and cleaner source. Electricity needs 2,5 times more of input primary energy (2,70MWhPRIM/MWhHEAT) than district heating (1,06MWhPRIM/MWhHEAT). In the context of sustainable development in this case, the use of electricity is a significantly less acceptable solution for the heating and hot water for our building.
    Solar energy (RES) from solar plant is to be used throughout the year. We have provided a solar power plant on our building roof with an installed capacity of 32.6 kW and an expected annual production of 34.3 MWh.

     PV system on the roof

    A photovoltaic power plant is located on the roof. Three variants were tested, we choose solar power plan type A, with fixed installation of panels on a gradient of 25°. Collected energy is used for electric cars charging points in the basement floor.

    PVstation1 PVstation3



    • living rooms and other rooms as an option
    • lights control via ICC
    • hall sensor lamp
    • PIR sensor: Passive InfraRed sensor is used to detect presence to automatically switch lights on and to detect intrusion when alarm is armed.
    • Auto-off: Light will automatically switch off after configured time. PIR sensor signal will extend auto off timer.
    • Fade-out: Light will turn off with soft fade out. Short fade out time is used for “fancy” light operation, longer fade out is used for leaving room when pushbutton is not at room leaving point.

     Building intelligent control centre

    The automated control via the Intelligent Control Centre (ICC) enables an optimal operation of devices and systems of the entire building and every individual apartment unit, no matter the season. The local weather station reports the current data to the ICC device. In the automated option the system can operate entirely independently by providing a healthy, high-level living comfort and rational energy use.
    Every resident will be able to set his/her own settings via the touch screen. The system enables a control of windows and doors closing, room temperature settings, ventilation rate, control over the turn-on of each lights and sockets, automated shade management, plant watering on the terraces (only in certain apartments), and the management of the videophone. All the communication systems and installations, including the optical and UTP connections are advanced and will also enable their adjustment to the new
    technologies in the future.


     Building envelope

     The most relevant building assemblies in building thermal envelope are ventilated façade system on the west and south side of building, contact facade on other sides and extensive green-roof system on 11th floor. For this segment calculation of thermal transmittance for all building assemblies that are the part of building thermal envelope were calculated.


    Thermal insulations which was implemented in passive part building envelope (residential floors from 1st floor – roof):

    a Contact facade:
    - Facade with a thin rendering + d = 20cm, mineral wool board Knauf insulation type FKD –S + brick wall 20cm

    b Ventilated façade
    - Rheinzinck ventilated fasade + mineral wool board type Knauff Insulation KI TP 435B 10cm + Knauff Insulation KI TP 435B (Ecose technology) with fleece 10cm, d = 20cm + brick wall 20cm

    c Windows
    - Manufacturer and supplier of windows is FTM :
    - Kömmerling PVC frame, reinforced: Uf = 1.0 W/m2K ,
    - Three-layer glass FTM: Ug = 0.6 W/m2K and Ug = 0.5 W/m2K
    - complete window: Uw = 0,82 – 0,94W/m2K
    - RAL installation of joinery : sealing material VBH :
    - Q - DUO folia
    - Q - Q K1/B2 Polyurethane foam
    - Q - DUO folia

    d Floors and ceilings in the loggias (avoiding thermal bridges):
    - Floor = WEDI board, d = 2cm + XPS insulation = 8cm, sum d = 10cm
    - Ceiling= Mineral wool board type: Knauff Insulation FP-PL, d = 10cm

    e Slab under 1st floor:
    - Above storerooms = mineral wool in board type: Knauff Insulation FP-PL, d =10cm- Above outer space = mineral wool in board type: Knauff Insulation FP-PL, d = 16cm + concrete renforced 25cm.

    f Roof over 11th floor:
    - On the roof = Ursa XPS N III-L, d = 10cm + Fragmat EPS 100, d=20cm, sum d = 30cm
    + reinforced concrete 25cm

    g Roof on the terraces (5-11th floor):
    - On the terraces = Ursa XPS N III-L, d = 20cm
    + reinforced concrete 25cm


    Facade thermal insulation in contact from 1st to 11th floor (source: Akropola)


    - Manufacturer and supplier of windows is FTM :
    - Kömmerling PVC frame, reinforced: Uf = 1.0 W/m2K ,
    - Three-layer glass FTM: Ug = 0.6 W/m2K and Ug = 0.5 W/m2K
    - complete window: Uw = 0,82 – 0,94W/m2K
    - RAL installation of joinery : sealing material VBH :
    - Q - DUO folia
    - Q - Q K1/B2 Polyurethane foam
    - Q - DUO folia


    Picture: Detail - windows / horizontal section (source Akropola)


     Picture: Positioning of windows (Source: GI ZRMK)

     Air permeability and moisture management (airtightness)


     Picture: Airtight apartment envelope and typical details (source Akropola)

    In order to be able to actively (by mechanical means) control indoor air parameters we have to prevent uncontrolled air exchange (from/to external environment). The building has to be airtight. This is achieved with the designing and construction of an airtight building envelope. This envelope is called the air-tightness layer. It is a special building element and has to be designed and constructed with special care. More air-tightness we need more demanding the design and construction of air-tightness layer is.
    Air-tightness can be measured and as such represented in quantitative way. Air change rate at reference pressure (n50) is most known quantitative information related to the level of building air tightness. It represents the ratio of the building volume that is exchanged in one hour when we apply 50 Pa of pressure difference between the inside (building) and the outside (environment). The measurement are normally carried out in accordance with EN 13829 standard, thus obtaining standardized values. This pressure tests are also known as Blower-door tests.
    With a quantitative value, we can set the desired level of building air-tightness at the planning phase and later monitor it.
    For the project EE-Highrise the value is n50 = 0,6 h-1.

    airtighness2 airtighness3

    Pictures: Practical implementation of airtight layer / vapor barrier after theoretical part. Gypsum walls in the pilot apartment (source Akropola)

    Blower-door test have been performed by GI ZRMK, assuming the following requirements for the ESH: air exchange in pressure test (Blower door), in accordance with EN 13829 standard: n50 ≤ 0.6 h-1 for Qh ≤ 15 kWh/m2a

     Water and waste water management

    Warm water preparation is done locally for individual apartments in the module for flow-through preparation. Constant pump driven hot water circulation system is installed in every unit. The domestic hot water demand of 25 litters of hot water per person per day at 60°C is standard value used for residential building by PHPP.
    All distribution pipes for domestic hot water preparation are insulated.


    Waste management

    Waste collection areas are located at all three entrances to the building with direct access from the entrance hall. Waste containers for separate waste collection are placed in the waste areas. Waste disposal access is arranged from Robiceva street.

     Green roof

    The roof is flat, partially walkable, with minimal inclination and a final extensive green layer. The edge of the roof is lined with painted sheet metal. A service path made from concrete slabs runs on the entire circumference of the green roof.


    Rain water harvesting / collecting

    A rainwater collection system is positioned on the roof. The collected water is used for flushing toilets in the apartments. Rainwater flows from the roof surface into the hoppers positioned above staircases A, B and C. The water is routed to the apartment toilets. Filling of the hoppers at low levels of rainwater will automaticaly switch to the district water supply. During heavy rainfall the overflow will be carried out to the roof drains. The hoppers have a built-in sensor for level control with a link to the system CNS (central control system).

    rainwater1 rainwater2

    Building equipment

    To be completed.

    Materials and solutions

    The chosen construction materials have properties that reduce the need for energy and reduce building maintenance costs. All the used materials have been chosen in accordance with the statics, construction technology and fire safety requirements The ecological demands have been considered in the largest possible way.

    The bearing structure is composed of reinforced concrete walls, columns and slabs. Building envelope consists of external walls, made of brick, insulated with mineral wool and windows with triple glazing and automated blinds.
    The interior walls are made of plasterboard with sustainable Ecose mineral wool as thermal and noise insulation. The floors are lined with oiled massive oak parquet. Bathrooms and toilets are finished with ceramic tiles.

    materials1  materials2

    Charging points for electric vehicles

    Collected energy from the photovoltaic power plant on the roof is used for electric cars charging points in the basement floor.


    Picture: An electric car charging in the basement

    Alarm / technical security

    Electronic access to the building and individual apartments in establishe by using fingerprints. Building 24h survailence will be established by the facility manager.