PUBLIC HOUSING RETROFITS IN ATHENS, GREECE

C. Vei Spiropoulou & associatesE. Triantis, associate architect

ELIUS - C. Vei Spiropoulou and associates, 36 Dragoumi Str., Athens, 115 28, Greece,Number +30 1 7210849, Fax Number. +30 1 7220760, E-mail address aspir@tee.gr

L.D.K. - Consultants engineers and plannersL.D.K. - Consultants engineers and planners, 7 Sp. Triantafylloy Str.,113 61 Athens, GreeceNumber +30 1 8629660, Fax Number +30 1 8617681, E-mail address kritikos@ldk.gr

ESBENSEN - Consulting engineers ESBENSEN Consultants Engineers and Planners, 54-56 Moellegade str., Soenderborg 6400 Denmark,

Number +45 7 4422250, Fax Number +45 7 4422674 , E-mail address torben.esb@esbensen.dk

Abstract – Aim of this project is to reduce the current heating and cooling requirements of two different housingbuildings (10 floor and 4 floor), by 80% and 35-40% respectively. In order to achieve these targets, innovativetechnologies will be incorporated, such as, external insulation of all facades, integration of passive solar systems,installation of water solar system, solar air heaters and photovoltaic panels.

1. INTRODUCTION

The Municipality of Tavros, one of the greater AthensMunicipalities has planned a renovation of the workers’housing units which form a considerable percentage of itsdistrict’s building stock. Tavros has 20.000 inhabitants ofwhich 6.000 live in the workers’ housing development.Following the recommendations of the E.C. Agenda 21for sustainable development and CO2 reduction, theMunicipality decided to introduce the integration ofrenewable energies and energy conservation systems inthe retrofitting process in two of the most characteristicbuilding types, in order to use them as pilot projects forthe intended renovation. In fact these buildings,constructed by the National Workers’ HousingOrganization on identical plans all around Greece, havean added value as pilot examples for hundreds of similarunits the country.

2. DESCRIPTION OF THE BUILDINGSSELECTED

2.1 PreliminariesFollowing an initial survey during the preparation of theproject proposal, two characteristic types were selected:

• TYPE A represents the older type of units builtaround 1950. These are bar-shaped 4 – storebuildings, with simplified and standardizedconstruction. They have no insulation or centralheating and have been extensively modified bytenants, who are also in most cases the owners ofeach apartment. Fig. 1

• TYPE B is a more recent type of building builtaround 1960. It is a 10-store building with a moreelaborated construction and central heating. Theseunits present a basic disadvantage in the orientationof the apartments, which face mostly east – west andhave little south exposure. Fig. 2

3. METHOLOGY OF THE INTERVENSIONSPLANNED

Following the initial contacts with building users asnecessary for the collection of energy consumption dataand detailed measurements of the buildings which wereconducted by members of the design team during the firstphase of the project, it was decided, before proceedingwith the design phase of the project, to undertake asurvey of the actual users’ needs and wishes concerningsolar retrofitting of their apartments.

This was considered necessary both by the municipalityand the designers, as according to the principles ofparticipatory design which are followed in the project,this survey will serve both as a source of information forthe designer concerning patterns of use, needs and wishesof the tenant on transition spaces of their apartments, butalso as a means of establishing more permanent contactswith the users themselves and introducing them to aspectsof energy - conscious design the efficiency of which willgreatly depend on their appropriate handing andmaintenance by the user, as a result of his approval andunderstanding of the project’s philosophy.

The methodology used for the survey was based on anopen questionnaire concerning the basic aspects of eachtenants’ everyday life in his apartment and especiallythose pertaining to the elements of transition between theinside and the outside, (balconies, verandahs, windows,doors, common spaces etc.). The questionnaire was filledin by the surveyor who visited selected apartments of thetwo buildings concerned, and interviewed the userstalking freely to them and recording patterns of use.Drawings and photographs of each apartment completedthe questionnaire.

Each questionnaire was composed of the following parts:

• Basic information on the users (name, age, family situation, profession, education,

presence at home, years of occupancy etc.)

• Use of the interior (Main and secondary spaces, internal circulation,

storage etc.)

• Relation between interior and exterior space (Patterns of use and appropriation elements - drawings,

photographs)

• Transition elements between inside and outside (Patterns of use, problems, user’s intervention or

additions, reasons of dissatisfaction, possibleimprovements needed)

• Neighborhood and social patterns (Relations with neighbors and other inhabitants,

distance to work, schools, shops etc., relation tonearby urban centers, appraisal of social aspects ofthis setting, ideal location and home for each user).

In terms of the chosen systems there is a different designapproach for each building type. Fig. 3

TYPE A

This building has been approached in a way stressing thecost-effectiveness of the systems used. I.e.• External insulation of the building (walls and roof)• Transformation of south-facing balconies into

sunspaces• Shading of south - facing windows• Solar water heating system placed on the roof of the

buildingTwo innovative systems will be included as follows:• Integration of solar air heaters on the south facade• Solar pre-cooling system using earth-pipes. Fig. 4, 5

TYPE B

This building has required a more complex approachbecause of major deficiencies in its construction andorientation of the apartment units. The main objectivehere is the combination of different systems in order toincrease the efficiency of the design.

Figure 1 : TYPE A – Existing building

Figure 2 : TYPE B – Existing building

Figure 3 : Meeting with the users

Figure 5 : TYPE A – Proposed South Facade

S.e. Interventions are as follows:• External insulation of the building• Addition of sunspaces on the south facade• Creation of a ‘’solar chimney’’ on the south side of

the building• Moveable glazing and shading elements for sun and

wind protection of east and west facing balconies• Centralized solar water heating system for the whole

building

Figure 4 : TYPE A – Typical Floor Plan

Figure 6 : TYPE B – Typical Floor Plan

• Creation of a collective solar space to be used by thetenants on the ground floor, including ademonstration space of the applied systems.

Innovative systems to be included:• Integration of a P.V. system to the south facade of the

building• Air heating system combined with the P.V. cells. Fig.

6, 7, 8

AA

Ä 4 Ä 1

Ä 3 Ä 2

4. EVALUATION OF THE SYSTEMS PROPOSED

According to the energy calculations concerning theefficiency of the proposed systems, conducted by theL.D.K. consultants and Esbensen consultants, thermalneeds of the buildings are covered by about 80% in thewinter for building Type A and 35-40% in the summerfor both buildings. The P.V. system will cover basicelectricity needs for collective spaces of building Type Band will have a capacity of 10 Kwp. Solar water heatershave an annual energy output of 500-600 Kwh/ m2, whileSolar air heaters are estimated to produce 200 Kwh/m2

per year.

5. CONCLUSIONS

This project is quite important for Greece, both for itshigh replication potential and for its integrated approachto retrofitting of existing buildings, using innovative r.e.and e.c. systems. It has been selected as a E.U. Thermieproject and will be monitored for one year afterconstruction.

Figure 7 : TYPE B – Proposed South and West Facade

Figure 8 : TYPE B – Proposed East Facade