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EXAMPLES OF RENOVATION DESIGNS
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CITY HALL – ERRENTERIA SPAIN |
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BUILDING CURRENT CONDITION – TECHNICAL AND OTHER PROBLEMS DETECTED |
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| The building was extensively renovated in 2000, hindering the task of encountering a balance between investment and energetic improvements. The envelope presents acceptable thermal transmittance and existing systems are relatively modern. The building does not present significant airflow infiltrations and it is regularly maintained. Concerning Renewable Energy Systems (RES), the geometry and location of the building represent major constrains for their installation. The building is located in the Old Town, characterised by narrow streets and urban density, which reduce the sun incidence on roofs. Furthermore the original building is listed and its historic value cannot be extensively altered. Additional equipment cannot be installed inside the building as each room has a well-defined use, limiting the selection of new systems to be installed. | |
ECONOMIC, FINANCIAL AND LEGISLATIVE CONSTRAINS |
BRIEF DESCRIPTION |
| Economic/Financial Risks The lack of public budget and the low availability of financial schemes can reduce the possibilities to implement the proposed renovation scheme. The equipment installed in the City Hall can be considered as modern and with a considerable remaining life time. Its efficiency might be improved by raising awareness of users but the effect cannot be easily quantified. Furthermore, in Spain PV system up to 100 kW may not sell electricity and are required to donate this electricity, thus extending the payback periods. Legislative Obstacles The City Hall was declared “Municipal ensemble” according to the Basque Government Decree 101/1996 of May 7th, which means that solutions with high visual impact or which might harm the building’s integrity cannot be applied. |
Errenteria City Hall has an appreciable square ground plan, which defines one side of the Herriko Plaza, the meeting point for five of the seven streets of the medieval town. The construction of the building started in 1603 and it was inaugurated in 1607. The City Hall suffered important damages, as Errenteria was burned in 1638 by the French troops. Looting and destruction were so extensive that, in a first attempt, it was decided to construct a new building. Nevertheless, in 1654 it was agreed to start with the reconstruction, which lasted till 1666. The City Hall corresponds to the typical Basque structure, made in sandstone ashlars. The building has a ground floor and two storeys, with a retracted raised part added at a later date. Each floor has four rooms distributed symmetrically. In 2000 an extension project started, which resulted in the merger of three existing buildings: the original building of the 17th century and other two buildings with less relevance, but contributing to the practical use and the overall streetscape. The project was undertaken to improve efficiency of the local government, facilitate circulation, structural stability and guarantee the unitary use of a single building. This entailed the erection of a new structure behind the original façades of the two less significant buildings. The historic City Hall was also renovated. The existing interior courtyard was kept as a key element of the plan yet covered with a skylight. The courtyard provides daylight to the interior office spaces. |
RENOVATION SCHEME |
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| Building Envelope As the building was refurbished in 2000, walls, roof and windows present thermal transmittance values that do not justify high investments, since the real impact in the energy demand reduction would be low. Improvement of thermal transmittance would require extensive works, entailing the temporary reallocation of functions and employees. The achievements will not be worth the investment. HVAC The heating system is a centralised system, independently regulated in different areas of the building. It is formed by radiators warmed by hot water produced by a gas boiler, supplying hot water to two buildings: Kapitain Etxea and the City Hall. As the system will be separated, the total power is currently. The heating system will be improved by means of a high Coefficient of Performance (COP) condensing boiler. The boiler proposed in the renovation scheme has a COP of 1.1 and a total power of 130 kW. The cooling system is divided in independent phases. The first phase is used to cool the administrative area, a double-flow air to air system. The second phase is a varied refrigerant volume (VRV) solution formed by 8 condenser units connected to 7 evaporator units. Each evaporator unit is independent and it is controlled manually by means of a remote control. Condenser units are controlled by timers that limit their working period to the timetable of the City Hall. The VRV system offers acceptable levels of energy efficiency and meets users flexibility, so no interventions are foreseen. Lighting In the renovation scheme proposed, fluorescent lamps will be substituted by LED lamps. Where possible, automatic controllers will be installed. RES The renovation scheme includes the installation of Photo Voltaic (PV) panels on the roof of the building. Considering the useful surface, panels will be installed on the sloped roofs. The plant, of 40.2 kWp, will be made of standard monocrystalline panels and will occupy a surface of 332 m2. |
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GENERAL INFORMATION |
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| Year of construction: | |
| 1603-2000 | |
| Area/Volume: | |
| 2,961 m2 / 11,418 m3 | |
| Building Use : | |
| City Hall | |
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LEARN MORE: Link to D2.1 pdf Link to D2.3 pdf Link to Guide or Brochure |
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EXAMPLES OF RENOVATION DESIGNS
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CITY HALL – ERRENTERIA SPAIN |
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RENOVATION SCHEME EVALUATION |
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| Energy Savings Currently, the building has a final energy consumption of 131,630 kWh in gas and 147,530 in electricity and a total primary energy consumption of 517,999 kWh. The renovation scheme proposed will reduce final energy consumption to 127,040 kWh in gas and to 60,783 kWh in electricity and to 286,954 kWh in primary energy. Primary energy savings will therefore be 231,045 kWh. Considering electricity and gas prices of 2015 in Spain, expenditure savings will be 12,374 € per year. CO2 Savings The CO2 savings are estimated in 57.36 tons per year. RES Integration 39% of energy will be supplied by renewable energy systems. PV will provide a generation of 38,757 kWh. |
PARAMETERS OF THE RENOVATION SCHEME- TOTAL
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ECONOMIC EVALUATION |
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| Payback Period The Project payback period is 9 years considering the maintenance savings but the cash flows are not sufficient to implement a financial structure at market condition. Total Cost The total investment cost is 169,684 Euro, which represents an investment cost per square meter of 57.30 Euro/m2. Economic Savings The energy expenditure is 11.698 Euro/year. The expenditure for maintenance after renovation is lower than before of 9.781 Euro/year. This situation affects positively, at economic level, on the total savings achievable by the intervention: the economic saving, energy and maintenance, is about 21.478 Euro/year. |
INVESTMENT FOR RENOVATION – TOTAL
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| FINANCING SCHEME | |||||||||||
| Energy Performance Contract It is necessary a restructuring of the investment plan and a contribution by the Municipality. The optimum scenario is: · Equity investment by the ESCo 9%; · Subsided Funds for 40%; · Grant for 40%; The type of contract to be applied could be the “shared savings” with a shared savings of 5% to reduce the payback. Duration of EPC The duration of the EPC contract is of about 20 years because the project has a long payback period. |
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LEARN MORE: Link to D2.5 pdf Link to D3.6 pdf Link to D3.7 pdf |
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