Case Study: nZEC - Energy refurbishment of 140 dwellings in Avenida Jacinto Benavente (Los Limoneros Project), Malaga, Spain

Short Description

The retrofitting of the complex “Los Limoneros”, focused on the improvement of the EE and comfort levels for the resident. Currently, the energy consumption is very low, this is mainly due to the fact that optimum comfort conditions are not reached.

The objectives established for this pilot project include:

- a cut in energy consumption of 40%;
- a decrease in energy expenditure of 20%;
- an increase of 2 energy grades;
- an investment for energy retrofitting of less than 30.000 euro per dwelling.

Key Elements

Certification

F (before retrofitting) -> D (after retrofitting) (according to the existing energy certification scale in force in the Spanish legislation).

ENERGY RATING (based on CO2 emissions (KG/CO2/year)):

• F (before retrofitting): 457,368.14 kg/CO2/year
• D (after retrofitting): 218,725.54 kg/CO2/year
  
  
  

Project Management

Stock conditions Assessment. The main conclusions of this simulation are:

• The number of discomfort hours is winter is very high (between 120 and 173 depending on the zone).
• The number of discomfort hours in summer is lower than in winter although both are very high (between 71 and 141 depending on the zone).

As expected, it is higher for the last floor because of the solar gain by the roof. In many hours of the year (about 3000 hours), external conditions are favourable to allow natural ventilation (Ej. free cooling in summer or “free heating” in winter). The cooling demand is 59.3 W/m2 and the heating demand is 35.2 W/m2 (referred to conditioned surface).

With regards to the compliance with regulation standards, the baseline situation has also been evaluated. CTE DB HE‐1 is the Spanish standard that limits the heating and cooling demand. The procedure consists of comparing individually each element of the building (walls, windows, etc.) with limit values. In a second step the cooling and heating demand for a reference building is calculated and compared with the actual building. The second must be higher than the first. LIDER and CALENER are the approved software to verify the compliance with standards. The main results include: - The actual U value of external walls does not comply with the regulations. The actual value is 1.74 W/m2K while the limit value is 1.22 W/m2K. - The U value of the floor in contact with the sanitary space below the building is 0.89 W/m2K while the limit value is 0.69 W/m2K. - The heating demand for the reference building is lower than for the actual building but the contrary occurs in summer (cooling demand). As a result, the actual building does not comply with standard and the envelope must be improved.
The selection process

From the technical point of view, the discussion in TMG to decide the best options to comply with the targets imposed by Elih‐Med project was based in the following aspects:

• Technical aspects: Energy consumption and comfort conditions obtained with each energy conservation measure
• Economic aspects: not only initial cost but also the operational and maintenance costs.
• Degree of Innovation: an important aspect that TMG has considered is the degree of innovation of the proposed solutions
• Social aspects: Due to the nature of the building, and input gained from the participants in the PPCG and the results of previous projects carried out in the building (some stopped due to the fact that the neighbours were not in agreement with what was being done), emphasis has been put on solutions that affect the whole building, giving benefits to more than the 60 dwellings previously stated.

This approach is supported by certain legal regulations in Andalusia such as the Decree 169/2011, which establishes that after retrofitting:

• A solar contribution of at least 70% must be attained for the entire building.
• The energy classification of the building must be at least D.

The list of the selected alternatives is the following:

• Solar thermal with cogeneration for heating sanitary water: As stated before, solar energy for the heating of domestic hot water is mandatory under Spanish regulation when an energy retrofit takes place. In order to provide electricity for the communal areas of the building, a small cogeneration system is proposed, something which is currently being used in the service sector but is very innovative for social housing. The contribution of both systems is 85% for domestic hot water. The difference (15%) is supplied by auxiliary systems placed in the dwellings.
• External thermal insulation of roof Solar heating by opaque roof is very important. By insulating the roof this gain is reduced. Insulating the roof produces a reduction of 11.5 % of the total consumption.
• External thermal insulation of the floor over the crawl space. It is mandatory to comply with LIDER (limitation of cooling and heating demand).
• External thermal insulation of walls (2 cm with). It is the minimum thickness of insulation and produces the higher reduction of energy consumption (12.9 %).
• Ventilation in the central patio by opening up the skylight. Opening  a section of the skylight that currently is in place above the internal patios will allow for cross ventilation between the dwellings and the internal patio. Dominant winds in Malaga come from east. Considering that the buildings is orientated mainly towards a north‐east axis, cross ventilation will be improved by making the internal patio permeable.
• Hybrid Ventilation system within the dwellings.

A participative process will be used to group together the relevant stakeholders at a local level, in a clear and organised way:

• The Territorial Management Group (TMG): Local stakeholders representing the key institutions that deal with energy efficiency and LIH. In charge of analysing the innovative financial and technical options and monitoring the implementation of the energy retrofit in the selected dwellings.
• The Pilot Project Participative Group (PPCG): Residents affected by the pilot projects, social workers, social landlords, local associations etc. that expresses the real life needs and problems that are experienced in the selected buildings, helping the TMG to develop and adjust the Action Plan to the reality of the situation.
  
  
  

Capacity Building

Transversal approach of ELIH-MED Project: Training staff/professionals /organisation and management staff/technicians/energy experts/social workers/caretakers/ technicians of building company or other key stakeholders.

Work with Residents

On the basis of the PPCG meetings and the recommendations given by the participants, an awareness campaign will be developed that adapts to the local situation and that focuses both on the residents of the buildings itself, residents within the local area and the low income housing segment in general throughout the city.

The campaign will focus primarily on the cost benefits of energy efficiency and what the residents can do in their own homes to better manage their energy consumption and therefore reduce costs. Finally, a closing event will be planned, again along the lines of energy efficiency and with a focus on the completed project and the benefits the users will have from there on.

45 Smart meters are installed in different dwellings and buildings, in order to assess energy behaviour of LIH consumers in Malaga City. During the analysis of the data obtained, energy advices reports will be delivered to the participants, as well as dwellings energy uses manuals to promote responsible energy consumptions and energy building refurbishments. Also a planning methodology working with residents to monitor use and environmental young workshops are implemented.

Funding

The project is co-financed by the 75% from ERDF and 25% from the Malaga City Council. The initial estimated refurbishment workings cost is 486,800.00 €. To conduct the ELIH-MED Malaga Pilot Project, it is foreseen that Malaga City Council will provide on their own funds supplementary financing. The amount of new financing will depend on the specifications of pilot project and its social context. We can roughly expect that new financing will be a maximum of 7.000 € per dwelling renovated.

Innovative financial mechanisms:

Our proposal is a financial mechanism that could be managed by an Energy Services Company (ESCO) or building cooperatives. It combines various different individual mechanisms including: Revolving Funds, Public Grants, Loan Guarantees and Soft Loans.

The ESCO model is also important in order to promote EEB refurbishments, however, as we are noticing in the Malaga pilot, in some milder Mediterranean climates, similar to Malaga, there is little potential for this model due to the small margins available for energy saving. This coupled with reduced economic resources of the LIH sector means that this particular model is particularly difficult to implement successfully 

The main advantages of this financial mechanism include high leveraging effect of financial mechanisms used, social implication, potential project continuity, economic and market development, improving energy performance on highly inefficient building stock. At the same time, we are working on establishing voluntary agreements with some of the private organisations collaborating in the project.

Thermal Insulation

External Thermal Insulation Composite System (ETICS) including 4 cm of EPS on vertical façades. External insulation of the roof and the sanitary space below the building.

Windows and Shading

Windows and doors remain unchanged. Currently, windows with single panes and aluminium frames are used. Internal blinds are used, operated manually.

Ventilation

An hybrid ventilation system of the central courtyard is proposed. The air of renovation comes from the sanitary space below of the building, using the soil as a cooling source. The renovation air is extracted from the top of the courtyard.

Heating and Hot Water

An hybrid, solar+micro-cogeneration system provides hot water for sanitary uses. The system combines 170 m2 of solar collectors with a 5 kWe cogeneration gas engine.

Solar Thermal

In conjunction with the micro-cogeneration engine covers 85 % of the heating demand to sanitary water.

Environmental Design

The project considered various bioclimatic concepts as building compactness, solar radiation and orientation, wind resources and effects and natural ventilation.

Main Results

• Expected results / improvements after the energy retrofit, the energy consumption is expected to be reduced by:- 75% due to solar contribution to heat sanitary water- 11.5% due to roof insulation- 12.9% due to ETICS (2 cm)- Less than 20% by increasing cross ventilation of the internal patio.
• With regards to the energy classification, the building will attain at least a “D” classification after retrofitting, therefore resulting in an improvement of at least two energy classification grades from its “F” classification that it has at present.
•  In relation with the Participative process and energy awareness raising; the results, impact and effectiveness of the Pilot Project in Malaga is foreseen to be fully successful, thanks to the project aim to develop and co-design, between residents and technicians, an innovative and realistic EEB refurbishment project considering the identified social, technical and financial approaches or weakness.
• The whole process has been supported by the TMG expertise and knowledge in order to develop energy efficiency in low income housing in Malaga’s context and to reduce energy poverty of the residents.
• It has been improved the knowledge related to low income housing stock and the identification of potential savings from new financing mechanisms that  are put in place. It has been identified the technical solutions which are available and can be applied efficiently in low income housings in Malaga City.
  
  
  

Lessons learned

Policy suggestions:

• Increase the subsidies that are available;
• Incentivise people to apply for this funding;
• Combine subsidies with funds that already exist;
• Assist people throughout the process of applying for subsidies;
• Coordinate and combine financial mechanisms and offer attractive conditions for the final user;
• Reinforce job creation as one of the base objectives for EEB;
• Combine both EE measures with Renewable energy measures in order to achieve greater benefits regarding energy consumption;
• Improve the participative processes to help generate awareness regarding energy efficiency and consequently promote more direct and immediate actions;
• Promote the creation of cooperatives or consumers group associations amongst building residents to facilitate the access to funds to carry out EE measures;
• Promote greater use of guarantee funds in order to cover the risks associated with more disadvantaged groups.
  
  
  

Additional Information

Ms Maria Jesús Gascó
AVS - The Spanish Association of Social Housing and Land Providers
E-mail: mjgasco@promotorespublicos.org
Web: www.promotorespublicos.org