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EXAMPLES OF RENOVATION DESIGNS
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MUNICIPAL LIBRARY– ALIMOS GREECE |
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BUILDING CURRENT CONDITION – TECHNICAL AND OTHER PROBLEMS DETECTED |
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| It is a detached building and the construction is a typical one of the period and region.The walls consist of double brick and reinforced concrete for the load bearing structure. The walls are insulated with 5 cm of extruded polystyrene placed in between the two brick layers and the roof slab is insulated with 8 cm extruded polystyrene. The windows have double glazing in an aluminium frame.The envelope has many thermal bridges due to the type of wall construction and these problems have not been addressed adequately in the thermal study. The building envelope does not present any problem with respect to airtightness.Also, splits and floor standing air conditioning systems are used for heating and cooling the building via electricity. The ground and the first floor use extra oil radiators for heating.Lighting is mainly supplied by fluorescent T8 lamps with magnetic ballast. | |||||||||||||||||||
ECONOMIC, FINANCIAL AND LEGISLATIVE CONSTRAINS |
BRIEF DESCRIPTION |
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| Economic/Financial Risks The fact that the municipality rents this building gives rise to risks as the relocation of the library might take place before the end of the payback period. However, this is considered a medium to low level risk.The total cost of the energy consumption is low and this fact affects the final payback period of the investment which is quite long for certain interventions. This happens because the daily operation is short and the energy demand of the services/activities taking place in this building is modest. Legislative Obstacles In a building which has central heating system it is not always easy to abolish this system and/or replace it with more flexible ones. This obstacle appears when there are more than one owner and not all of them agree with this change. In this case the regulation regarding multi – owner buildings applies and requires either a unanimous vote or a majority vote. For this reason the most feasible choice is to improve the existing central heating system. Likewise, the installation of PVs on the roof has to be approved by all owners of the building. |
The Municipal Library building was constructed in 1984. It comprises five floors and a basement. The Municipality rents the first three storeys and the basement and houses the Municipal Library, offices, school activities and dancing courses. The rest of the building is residential. The shape of the building is elongated along the N-S axis. The orientation of the whole complex deviates 53o from south due west. The occupation profile of all floors is from 07:30 to 15:30 on week days. The employees of the Municipal Library are 13 and the visitors are around 70 per day. | ||||||||||||||||||
| RENOVATION SCHEME | |||||||||||||||||||
| Building Envelope Opaque Envelope: The most suitable option is the addition of 5 cm external insulation of 0.032 W/mK. Glazing: The optimum choice should have low–e coating glazing and window mean U-value 1.80 W/m2K. Natural/Night ventilation: Air vents equipped with dampers will be installed on the north and south façade of the building so as to achieve cross ventilation on each floor. HVAC The existing systems will be replaced with new A/C systems more efficient [EER 3– 4.4] and they will be used only for cooling.Regarding the heating of the building it was considered that the optimum choice is the conversion of the old boiler to a new Pellet boiler which is more environmental friendly. Also the central heating system pipes will be insulated and the central heating water pump will be replaced with a new one inverter technology in order to reduce the electricity consumption. Lighting All lamps of the building will be replaced with new LED lamps. Also, daylight sensors will be installed on the luminaires located close to the windows. RES A photovoltaic system of 5.73 kWp will be installed on the building’s roof and the annual energy production will be 8,040 kWh. Thermostats and power meter The use of a Thermostat in every room of the building will ensure that the desired internal air temperature will be stable and will prevent the excess use of energy. Additionally in order to record and storage the energy consumption of the A/C system, lighting and pc units so as to detect the energy intensive units we will install power meters to the electrical board of each floor. |
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GENERAL INFORMATION |
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| Year of construction: | |||||||||||||||||||
| 1984 | |||||||||||||||||||
| Area/Volume: | |||||||||||||||||||
| 611 m2 / 2,185 m3 | |||||||||||||||||||
| Building Use : | |||||||||||||||||||
| Library-Offices | |||||||||||||||||||
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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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MUNICIPAL LIBRARY– ALIMOS GREECE |
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RENOVATION SCHEME EVALUATION |
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| Three alternative renovation options were carried out without the building envelope improvement with the aim to achieve lower payback time for the renovation investment and increase the potential to attract private funding. Option A excludes only the external insulation, Option B excludes only the replacement of the glazing and Option C excludes both interventions. Among all the options only the initial one satisfies the CERtuS targets but the most financially attractive was the Option C. As can be seen the savings are comparable between the two options but the cost and the simple payback period are varying substantially. For this reason Option C was selected for implementation. Energy Savings The primary energy consumption (for heating, cooling and lighting) before renovation 122,195 kWh/year and the primary energy consumption per square meter is equal to 241 kWh/m2. After renovation (Option C) the consumption is reduced to 15,148 kWh/year or 29.9 kWh/m2.Specifically, the energy efficiency interventions, excluding the electricity generated by the PV system, reduce the consumption of the primary energy to 75.8 kWh/m2 by generating savings equal to 83,728 kWh/year. These savings represent 68.5% of the energy consumption before renovation. The remaining demand for electricity is covered up to 63% by the PV system which produces 8,041 kWh/year. Additionally, the energy consumption for heating is covered by biomass which means that in total 90% of the building’s energy demand is covered by renewable energy sources. CO2 Savings The CO2 savings resulting from Option C are 39.73 tons/year. |
PARAMETERS OF THE RENOVATION SCHEME- TOTAL
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ECONOMIC EVALUATION |
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| Renovations cost The cost of the interventions which are excluded is 38,007 € for the external insulation and 50,000 € for the windows. Economic Savings The total annual economic savings are equal to 4,667 €. The energy expenditure savings are 6,167 but post renovation maintenance is higher than before by 1,500 €/year. |
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| FINANCING SCHEME | |||||||||||||||||||
| Under the current challenging economic conditions, municipality of Alimos has limited financial resources for implementing the energy retrofit of the selected buildings. The most suitable financing model is to assign the project to an Energy Service Company (ESCo). The ESCo is responsible to secure the total investment cost, the implementation of the project, the maintenance during the contract period and, guarantee the energy performance of the agreed solutions. The money savings, corresponding to the energy savings, will be shared between the ESCo and the municipality of Alimos, according to the “Shared Savings” model contract. Financial Structure of Project The most market efficient financing source for implementing the project is market money (private equity, bank loan), followed by Subsidised Loan. The least favourable one is Grants since they have zero revolving effect; Grants’ money once used, they never come back to the market. Even so, in many nZEB renovations Grants are necessary for turning a project market attractive and marketable. The optimum financial structure should involve the provision of sufficient subsidised loans as the latter improve the attractiveness of the project and make it marketable. According to the study the optimum financial structure consists of:· Equity investment by the ESCo – 24%· Subsidized Loan – 65%· VAT Facilities – 11%The expected project payback period is approximately 15 years, while the duration of the EPC is 15 years which is not favourable but still market acceptable. Other considerations The EPC takes into provision that the relevant money savings are allocated to the repayment of the investment, allowing 10% annual money saving to be enjoyed by the Municipality who has zero contribution to the capital cost. Once the EPC is concluded all money savings will be enjoyed by the Municipality. |
INVESTMENT FOR RENOVATION – TOTAL
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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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