What we are doing for the municipality
We have carried our interventions for the energy refurbishment of the municipal offices and secondary school S.Gnutti, thereby guaranteeing for 10 years the service of heat and energy management for the buildings in question.
In detail, the service of heat and energy management consists of the planning and execution of interventions and/or measures with the following purposes:
- Executive planning and execution of the energy refurbishment interventions for the buildings
- Optimisation of the energy management of the plants
- Control and reduction of the costs and energy consumption
- Ordinary maintenance and management of the plants, in addition to third party responsibility
- Economically advantageous access to energy supply
Scopri i dettagli dei nostri progetti di riqualificazione ed efficientamento energetico
ANALYSIS OF THE CURRENT STATE
The main critical points detected within the entire building-plant system concerned:
- All of the external walls in masonry and stones were completely without thermal insulation
- The internal floor structures in contact with areas that are not heated or with the outside, in particular those of the top floor, were not sufficiently insulated
- The building was already equipped with large glass surfaces, exposed on all of the facades. The window fittings present were in aluminium and the glass chamber lacked a thermal break
- A part of the window fittings present were equipped with PVC shutters, the containers for which were not insulated, therefore representing a worrisome source of thermal bridge, in particular for school buildings because of the high humidity levels present in classrooms often leads to the formation of condensation and consequently mould and bacteria, which is damaging for students and teachers alike
- The existing heating unit, which was powered by methane gas, was composed of a heat generator connected to a air blowing burner, with a heating capacity of 365,853 kW with features and technologies that are now outdated and therefore no longer effective. As a result the performance was merely acceptable
- The situation from the perspective of compliance with regulations and safety highlighted some problems
- Electric boilers were present for the production of sanitary hot water
- The circulators installed used technology that is now obsolete or outdated, with high consumption levels,
- No renewable energy source plants were present
- The thermoregulation plant was not optimised and showed some inefficiencies, enabling control and modification of only some of the main system parameters;
- The installed internal devices were out-dated or obsolete, leading to high electricity consumption and a quality of lighting that was only just sufficient for the needs of the occupants
- The work carried out contributed substantially to the notable improvement in the building’s energy performance and in particular:
- Improvement of the transmittance of the structure’s opaque vertical elements facing the outside with the creation of a thermo-isolating covering with expanding polystyrene panels of a thickness of 120mm and thermal conductivity equal to 0.033 W7mK;
- Improvement on the transmittance of the opaque horizontal elements of the structure facing outwards with the creation of isolation of the extrados of the interior floor of the top floor with the laying of TRISO-MURS+ isolation, thin multi-reflecting ACTIS isolation
- Improvement of the transmittance of the transparent vertical elements including windows with the removal of existing window frames and the installation of new PVC frames that are double glazed and low emissivity, having Uf 1.8 W/mqK and Ug 1.1 W/mqK;
- Control of solar irradiation with the possibility of total darkening thanks to new aluminium blinds and monoblock containers in thermal isolating PVC;
- Improvement of the performance of the generation subsystem with the removal of existing boilers and the creation of a new modular condensation generation plant with a heating capacity of between 28.1kW and 150 kW. This was to maximise the capacity for modulation of the thermal heating capacity to the radiators. A plate heat exchanger was also installed in order to increase the useful life of the new generator
- Adaptation of the systems to meet current safety regulations
- For the production of hot water the current system of electric boilers was maintained because it was considered appropriate, and adequate to the necessities of the users and the type of building
- The two new electronic regulating circulators enable the minimisation of consumption based on the effective requirements of the circuit, coupled with new anti-tampering thermostat valves installed on the radiators in the classrooms. This establishes greater regulation of the internal temperature of the rooms where this equipment has been installed, resulting in energy savings
- Use of renewable sources of energy through the creation, on the portion of the roof facing south, of a photovoltaic system of panels connected to the network with a capacity of 20kWp
- The existing system of thermoregulation has been integrated and enlarged to ensure the control of all components of the plant, the regulation and control of system areas, the boilers, the production of hot water, the verification of fluid temperatures and ambient temperatures, the monitoring and registration of energy consumption in addition to the management of alarms
- All of the internal lighting equipment of the school was replaced with new more efficient equipment leading to electric energy savings of around 30%.
ANALYSIS OF THE CURRENT STATE
The situation from the energy perspective prior to our interventions was typical of public structures using materials and ideas that differ from the current planning approach that is more focused on energy efficiency. The building was constructed at various different times beginning from the late 1930s and therefore consists of a collection of different spaces.
In particular, the main problem areas concerned:
- The poor performance of the covering due to the materials used and the presence of thermal bridges: the roof is flat and poorly insulated; the vertical weight-bearing structures are made of reinforced concrete, the external walls in breeze blocks without insulation, with portions clad in marble and other portions in sheet metal
- The presence of window and door fittings in aluminium and glazing without thermal breaks and parts in iron with simple glass, are now out-dated and current models on the market offer better performance in terms of heat and sound insulation concerning the structure of both window frames and the glass
- Due to the position of the building with relation to the sun, the large main façade, which is not equipped with adequate systems of external shading, heats up excessively
- The heating unit present, which is powered by methane gas, was composed of two old heat generators each with a heating capacity of 383,70kW combined with an air heater, that has modest performance levels and a yield that is merely acceptable
- Presence of a limited capacity photovoltaic plant, which was sufficient to satisfy only a small share of the energy necessary for the building
The purpose of the project was energy saving, created with the following types of intervention:
- Insulation of the main building covering with prefabricated sandwich panels of a thickness of 120mmm and thermic conduction equal to 0.033 W/my; the creation of a thermo-insulating covering on the external vertical walls with expanding polystyrene panels of a thickness of 120mmm and thermal conduction equal to 0.033 W/mK
- Replacement of existing window frames as indicated in the graphs, with new high-energy efficiency PVC window frames (Uf 1,3 W/mqK and Ug 1,1 W/mqK). The windows will need to have glass that conforms to the specifications of the regulations UNI 7697 and UNI EN 12600 concerning the destined use
- Creation of moveable shades on the windows on the southern side of the building on the first and second floors
- The old boilers have been replaced with a single freestanding condensation boiler, in view of the improved performance and greater savings that this ensures, with heating capacity of only 479 kW, reducing the capacity of the two old boilers by 288kW. To increase the useful life of the new boiler a plate heat exchanger has been installed.
For the new heating and cooling generation system an innovative technology was selected: the two-stage heat pump. This is an evolution of the conventional heat pump currently present on the market, with characteristics of higher performance and a COP index, in particular at low superior temperatures, comparable to conventional technology.
To optimise the performance of the entire plant in every space, electronic multi-speed circulation pumps were installed as well as anti-tampering thermostat valves on the radiators in the classrooms.
For the production of sanitary hot water, it was decided to replace the existing boiler with a new one.
The plants were adapted to meet the current safety regulations.
To monitor and manage the heating unit in real time a remote control system was adopted.
- Creation of a new photovoltaic plant and its connection to the network with capacity of 15kWp integrated with the existing photovoltaic plant
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