A multi-objective optimization approach of housing in Algeria. A … · 2021. 3. 10. · Urbanism A Multi-objective optimization approach of housing in Algeria […] ] • K. Djebbar,

Urbanism A Multi-objective optimization approach of housing inAlgeria […] • K. Djebbar, S. Salem, A. Mokhtari

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A MULTI-OBJECTIVE OPTIMIZATION APPROACH OFHOUSING IN ALGERIA. A STEP TOWARDS SUSTAINABILITY

Khadidja El-Bahdja DJEBBARLecturer, Ph.D Student, Department of Architecture, Faculty of

Technology, Abou Bakr Belkaïd University, Tlemcen-13000, Algeria, e-mail:[email protected]

Souria SALEMProfessor, PhD, Department of Architecture, Faculty of Architecture and

Civil engineering, Mohamed Boudiaf Sciences and Technology UniversityU.S.T.O, Oran-31000, Algeria, e-mail: [email protected]

Abderrahmane MOKHTARIProfessor, PhD, Laboratory of Materials Soil and Thermal, Faculty ofArchitecture and Civil engineering, Mohamed Boudiaf Sciences and

Technology University, U.S.T.O-MB, Oran-31000, Algeria, e-mail:[email protected]

Abstract. The present study focuses on the evaluation of the energy andenvironmental performance (EEP) of a typical multi-storey building inTlemcen, Algeria. It aims to contribute to the development of Algeria’sthermal regulation by establishing a list of actions to be taken in short,medium and long term, in terms of thermal rehabilitation in existinghousing areas as well as in new ones, in urban regions with a similarclimate. An appropriate multi-criteria methodology is developed bydetermining its thermal performance using a static method as well asestablishing a multi- objective strategy of EEP optimization. Theassessment of: the potential of primary-energy-saving and that of the CO2-emissions’ reduction and indoor-environmental-quality of a real state ofconstruction by simulation using DesignBuilder software, together withinvestment-cost are reported. Therefore, this study is conducted using thepotential of parametric evaluation methodology to investigate the impact ofpassive energy-efficiency-measures on the building envelope from energy,environmental, economic and thermal-comfort points of view. Insulationand ventilation reduction are the main measures saving more than 75% ofenergy and 44% of CO2-emissions. Besides, the winter comfort issignificantly improved. But from the economic standpoint, policy measuresmust be taken; namely tariffs reforms and energy control law enforcement.

Key words: Multi-storey-buildings, Energy-Performance, Simulation,Passive techniques, CO2 emissions.

• Urbanism. Arhitectură. Construcţii • Vol. 9 • Nr. 2 • 2018

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1. IntroductionNo society is balanced and in harmonywith nature unless housing is sustainable(Armstrong et al., 2005). The residentialsector in Algeria is the source of near 43%of final energy consumption (MEM,2016). Thereby, it has an equallyimportant share in the CO2 release. Theperspectives of Housing ParkDevelopment will drive to an exponentialincrease of this consumption, if theenergy control regulation will not beapplied. Popular pressure on housingrequest pushes to quantitativerealizations and non-qualitative: totalabsence of energy efficiency. It is testifiedby the inefficiency of control andsanctions mechanism and thereaboutseven the non-application of the thermalregulation in new buildings which has tobecome operative from 2005 (Sénit, 2008).

Energy conservation marks a route forextending available energy resources.While Ouahab (2015) has found that, bycontinuing current trends to 2050, energyconsumption in the Algeria’s residentialsector in the trend scenario could reachnearly 413.4TWh/year, while they areapproximately 117.4TWh/year in 2008.This corresponds to a very high growthrate of around 250%. In this scenario, theshare of heating would represent 57% ofthe total consumption, ie 233TWh peryear, and that of appliances almost 19%(78.2TWh). Together, these items wouldtotal more than 75% of the park's needs.The shares of other uses would remainrelatively low: 7% for DHW, 7% forcooling and 10% for cooking.

Overall, the share of energy consumptionin the single-family home segment isdecreasing in favor of multi-family units.It would rise from 66% in 2008 to almost62% in 2050. The share of housing inmulti-storey-buildings would rise to

more than 17%, compared with only 9%in 2008.

As regards the evolution of CO2

emissions, it has been found thatemissions would increase at the rate ofthe increase in energy requirements, sincethey would increase by more than 270%,ie 112.7MtCO2, compared to 2008emissions (30.6MtCO2). The average percapita emissions would reach theequivalent of 2.1tCO2/capita in 2050,while they were only 0.9tCO2/capita 2008(Ouahab, 2015).

It thus discharges the importance ofregulatory measures relative to thermalperformances of buildings as well as theneed of detailed studies specific to eachcontext. In fact, many studies have beenelaborated at international, regional andlocal scale to improve EEP of existinghousing buildings. All these studies aimto help to make decisions for choosingthe appropriate combination of passiveand active measures. Methods andenergy-saving effectiveness vary from astudy to another.

The most used methods assess thebuilding performances on energy aspects,others multi-criteria-methods evaluatemost widely the environmental impacts:a) Benchmarking» (Tereci et al., 2013); b)Follow up of consumption to a referenceyear (Shorrock and Dunster, 1997;Boardman et al., 2005); c) Audits (energyand environmental) (Belpoliti andBizzarri, 2015; Terés-Zubiaga et al., 2015);d) Post Occupancy Evaluation(Elsharkawy and Rutherford, 2015); e)Life cycle analysis method (Hamdy et al.,2011; Jaber and Ajib, 2011; Huang et al.,2012; Ramesh et al., 2012; Berggren, 2013;Junghans, 2013; Lewandowska et al.,2013); f) Ecologic footprint (Konstantinouand Knaack, 2011); g) Experimentation or


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energy simulation using parametricmethod to assess the envelopecharacteristics impact on heating andcooling systems (Yu et al., 2008;Wasilowski and Reinhart, 2009;Awadallah, 2011; Griego et al., 2012;Charde and Gupta, 2013; Oropeza-Perezand Østergaard, 2014; Belpoliti andBizzarri, 2015).

The state-of-art and sustainableevaluation of energy efficiency measures(EEM) of residential buildings is usuallyperformed using not only one criterion,but composing several ones(Mikučionienė et al., 2014; Seddiki et al.,2016). The selection of criteria depends onthe aim of analysis. The most popularcriteria for evaluation of EEM are energyefficiency (EE) or energy saving (Yu et al.,2008; Sun, 2013).

Swan and Ugursal (2009) have providedan up-to-date review of the variousmodeling techniques used for modelingresidential sector energy consumption.Two distinct approaches are identified:top-down and bottom-up. The top-downapproach treats the residential sector asan energy sink and is not concerned withindividual end-uses. It utilizes historicaggregate energy values and regressesthe energy consumption of the housingstock as a function of top-level variablessuch as macroeconomic indicators (e.g.gross domestic product, unemployment,and inflation), energy price, and generalclimate. The bottom-up approachextrapolates the estimated energyconsumption of a representative set ofindividual houses to regional andnational levels, and consists of twodistinct methodologies: the statisticalmethod and the engineering method.Each technique relies on different levelsof input information, different calculationor simulation techniques, and provides

results with different applicability (Swanand Ugursal, 2009).

For a building in operation stage, heatingand cooling requirements intensity,expressed in useful or primary energy(EP) by unity of area (kWh-equivalents/m².year or GJ/m².year),constitute a pertinent indicator of itsthermal performances, especially of itsenvelope (Djelloul et al., 2013).

The energy efficiency criteria are oftenused together with criteria ofenvironmental impact (EI) and inliterature is presented as ‘2E criteria’(Mikučionienė et al., 2014). Belpoliti andBizzarri (2015) have used the parametricassessment method in terms of evaluatingenvironmental and energy benefits,deriving from scheduled retrofit actions,to assist technicians in endeavoringinterventions priority. Analyzing theoutcome data, a simplified parametriccalculation protocol has been created tooperate a preliminary audit and energyretrofit simulation on the entire socialhousing stock of the Region Emilia-Romagna, Italy, in terms of both theirenvelopes and heating systemcharacteristics (Belpoliti and Bizzarri,2015).

The economical rationality (ER) criterion,as ‘3E evaluation’, is the most used instudies. Shen and Sun (2016) note thatthere exists an inverted “U-shaped” curveconnection between carbon emission,energy consumption and economicdevelopment (Shen and Sun, 2016).Tommerup and Svendsen (2006) havegiven a short account of the technicalenergy-saving possibilities that arepresent in existing dwellings and havepresented a nancial methodology usedfor assessing energy-saving measures. Inorder to estimate the total savings


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potential, detailed calculations have beenperformed in a case with two typicalbuildings representing the Danishresidential building stock and based onthese calculations an assessment of theenergy-saving potential is performed(Tommerup and Svendsen, 2006).

Hamdy et al. (2011) have proposed amodified multi-objective optimizationapproach based on Genetic Algorithmand combined with IDA ICE program.The combination is used to minimize theenvironmental impact and the investmentcost for a two-storey house and its HVACsystem. Heating/cooling energy source,heat recovery type, and six buildingenvelope parameters are considered asdesign variables (Hamdy et al., 2011).Ouyang et al. (2011) have developed amethod demonstrated by a case study. Asuitable energy-efficient renovation planis put forward, integrating all effectiveand available energy-saving measures,for the subject building and its effects onreduction of energy consumption, CO2

emissions and cost are evaluatedaccurately in China (Ouyang et al., 2011).

Popescu et al. (2012) have appliedmethods that quantify the added valuedue to energy performance, includingrecommendations on how they can beincorporated in the nancial analysis ofinvestments in weatherization. Casestudies on some existing condominiumsfrom Romania are analyzed and provideevidence to the research question(Popescu et al., 2012). Missoum et al.(2014) have analyzed the energyperformance of rural housing built in thedistrict of Chlef, Algeria, for the threeconstruction programs, besides studytheir impact on the overall energybalance in this district, through towmeans: Passive mean by integrating a setof EEM and active one using solar PV for

electricity (Missoum et al., 2014). Aneconomic study has been presented butwhich is not truly realist concerning theEEM cost. Arumägi and Kalamees (2014)have analyzed the energy consumptionand potential energy saving basing onfield measurements, computersimulations and economic calculations.The renovation packages were compiledusing different insulation measures,HVAC solutions and energy sources(Arumägi and Kalamees, 2014).

The thermal comfort (C) or indoor-environmental-quality (IEQ) is alsowidely used. Carlucci and Pagliano(2013) have optimized the building withthe objective to maximize the thermalcomfort of the users. They applied amethod to design a new net zero energybuilding, analyzing a set of passivemeasures (insulation and windowsperformance). Their objective was toreduce the heating and cooling demandthrough the comfort improvement(Carlucci and Pagliano, 2013). Liu et al.(2015) have evaluated both the indoorenvironment and energy use of theretrofitted building in comparison with asimilar non-retrofitted building from thesame area. The case study is a multi-family building which representscommon type of construction in the cityof Linköping, Sweden (Liu et al., 2015).

Sun and Leng (2015) have investigatedthe typical indoor environment in Tibetanresidential dwellings. Tibetanarchitectural features and ethnic customsare taken into account in the creation ofpassive renovations that are applied withminimal effect on the overall architecture.Numerical simulations of the indoorthermal environment are conducted onthe building models using DeST-h.Different renewal measures are evaluatedin terms of how much they decrease


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annual energy consumption. Orthogonalexperiments are designed to optimize anarray of energy-saving buildingrenovations to reduce energyconsumption and improve indoorthermal comfort of Tibetan residentialhouses. The conclusion is that there areeconomic and environmental benets ofusing natural passive methods withoutconsidering mechanical ways (Sun andLeng, 2015).

Ortiz et al. (2016) have presented adetailed method to develop optimal-costsstudies for the energy renovation ofresidential buildings in Barcelona andTarragona, Spain. The method allowsimproving the interaction between theoccupancy and the building, and thecharacterization of the real state of theconstruction. In addition, the buildingsimulation includes vernacular strategiesof the Mediterranean architecturethrough two-steps evaluation consideringthermal comfort, energy and economiccriteria (Ortiz et al., 2016).

Environmental and energy efficiencycriteria are usually met with Life cycleanalysis (LCA). Mikučionienė et al.(2014) have defined and analyzed thefive main criteria for EEM evaluationreflecting sustainable attitude (energyefficiency, environmental impact,economical rationality, comfort andduration under Life Cycle point of view(LCD)). Sequential prioritization anddistribution of decision tree is formed fordistribution of EEM to the basic andadditional energy efficiency measures.The presented method optimizes theformation of packets of EEM(Mikučionienė et al., 2014). Lawania andBiswas (2016) have assessed the highgreenhouse gas (GHG) emissions andembodied energy (EE) consumptionassociated with the construction and use

of a typical house in Perth for sixtybuilding envelope options using a lifecycle assessment (LCA) approach(Lawania and Biswas, 2016).

Multi-objective optimization, as its nameimplies, is the process of systematicallyand simultaneously seeking one or morebest solutions with respect to two or moreobjective functions. Multi-objectiveoptimization problems are fundamentallydifferent from single objectiveoptimization problems. Single-objectiveoptimization identies only one globallyoptimal solution. However, multi-objective optimization problems ofteninvolve multiple competing, conictingand incommensurate objectives (Wu,2016).

Gossard et al. (2013) have adopted amethodology that couples an articialneural network and the genetic algorithmNSGA-II to reduce the computationalrequirements of a dwelling for twoFrench climates, Nancy (continental) andNice (Mediterranean). The optimalsolutions are compared to those frommono-objective optimization by using anaggregative method and a constraintproblem in GenOpt. The comparisonclearly shows the importance ofperforming multi-objective optimization(Gossard et al., 2013).

This partial inventory allowsdemonstrating the interest of ourdemarche which enrolls in a universalscientific effort. As, it demonstrates theabsence of specialized and deepenedstudies at local level therein as well as theabsence of a holistic approach of asustainable evaluation of EEP ofresidential buildings suitable to Algerianand Maghreb’s context. The choice tosimulate only the passive measuresreveals judicious, that attests the similar


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results observed in the scientific studiesnamed.

So, the originality of this study, which is apart of a project that analyses differentenvelopes of multi-storey buildings atTlemcen, involves the analysis of EEP of atypical dwelling in this town using amulti-criteria assessment of available andaffordable EEM through static anddynamic methods. By, the definition ofthe energy-saving potential and that ofthe CO2-emissions’ reduction to reach theupper performance levels, as well assetting an order of priority to classifyactions to take in short, medium and longruns. In order to contend wastage,improve the comfort, reduce negativeenvironmental impact and extend the lifecycle of the building.

In addition of the comparison of itsconsumption with another existentenvelope of the same period, byestablishing an internal benchmarkingand an external one compared to regionalregulations. Moreover, we will check thefeasibility of these measures in theAlgerian context from an economic pointof view. This will contribute to thecomplement of the Algerian thermalregulation and its upgrade. And help tomake decision about choosing theappropriate combination of passivemeasures.

2. MethodTo evaluate correctly the EEP ofresidential buildings at Tlemcen, thispaper develops an appropriatemethodology:· Step 1: Field study is a dwelling in

multi-storey buildings dating fromthe post-independence period inTlemcen town. Collectingdocumentation on: the selected casestudy, at the end of a previous study

that indicated it as the least efficientcase; regular framework of energycontrol in residential buildings inAlgeria; urban population statisticsand households energy consumptionin this town;

· Step 2: Collecting and evaluatingclimatic data;

· Step 3: Establishing the thermalbalance through static method bysimple calculation of thermal lossesof a middle apartment and anotherin top floor, in order to orient therehabilitation actions. In additionto, checking of their thermalconformity according to regulatorymethod presented in RegulatoryTechnical Document DTR C3-2 of10/12/97;

· Step 4: Establishing a strategy oflosses reduction by using anenvironmental and economicalapproach concerning the choice oflocal materials stemming fromrecycling and by placing those themost ecological inside the apartmentand the less ecological ones outside it;

· Step 5: Recalculate the thermal lossesof apartments after rehabilitation byperforming an external benchmarkingby comparing the Algerian thermalregulation to regional ones (Moroccanand Tunisian);

· Step 6: Simulate the energy used bya typical household occupying thisapartment by dynamic methodsusing the couple of «DesignBuilder/Energy plus ».Occupation, building and thecharacteristics of a real state of theconstruction is presented later.

· Step 7: Investigate the impact of somepassive EEM often used through theimprovement of building envelope’selements, as (ventilation, insulation,orientation, greenhouse effect andshading devices) by using the


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potential of parametric study in thesimulation through tow means:1) Simulate an active case of the

real/actual/existing case beforeand after thermal rehabilitation;

2) Simulate a passive case of thereal/actual/existing case beforeand after thermal rehabilitation ofthe optimized case;

· Step 8: Perform a multi-criteriadecision making analysis to therehabilitation according quantitativeand qualitative factors (energy-savingand environmental potentials,investment cost, thermal comfort andlife cycle duration), by trying toposition cases relative to theinternational label “Low consumptionbuilding label BBC (Bâtiment basseconsummation)” and the regional one“Tunisian label” (see Appendix A);

· Step 9: Simulate a second envelopedating from the same period of thecase study. In order to compare theirconsumptions and theirenvironmental impacts byestablishing an internalbenchmarking;

· Step 10: Compilation, synthesis of thecollected information and resultsdiscussion;

· Step 11: Redaction ofrecommendations by order of priorityin short, medium and long term, interms of thermal rehabilitation inexisting housing areas as well as innew ones.

3. Regular framework of energy controlin residential buildings in AlgeriaAlgeria having adhered at

different treaties of climatic changes andenvironment protection, in sustainabledevelopment framework, had to adapt itslegislation at the new internationalcontext. Since, an ensemble of regulartexts, relating to the energy conservation

in building, has been adopted. In the 1990years, Algeria has developed manyregulatory devices regarding the energyefficiency in housing. According to areflection on passive and activeconsumption of new dwellings initiatedin 1995, the National Centre for Studiesand Integrated Research of Building(CNERIB) under Housing and UrbanPlanning Ministry tutelage has ledresearch works and has positionedRegulatory Technical Documents (DTR)in 1997:· The DTR C3-2 of 10/12/97 which

establishes Calculation of WinterCalorific Losses Rules for HousingBuildings (fixing the methods of:calculation of calorific losses ofbuilding, checking the conformity ofbuilding to the thermal regulation,sizing the heating fixture in buildings)(CNERIB, 1998);

· The DTR C3-4 of 18/08/98 relativeto the Rules of Calculation ofSummer Calorific Gain for Buildings(fixing the methods of definition ofbuilding’s calorific gains and thechecking method of their conformityto the summer thermal regulation.These DTR have subsequently beenapproved by Energy and MineMinistry, and have made, in 2000,the executive decree n°2000-90 objectsupporting thermal regulation innew housing buildings and others,plus parts of realized construction asexisting buildings extension, in theapplication of the law n°99-90 of28th July 1999 relative to energycontrol.

· Also, the DTR C3-31 of 12/04/2006relative to Natural Ventilation ofHousing Usage Areas (fixing thegeneral standards to have to adoptduring the conception of naturalventilation fixture, the calculationmethods allowing their sizing).


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In the extension of the spirit of the law onenergy control, the main lines of thenational strategy for the control of energywere adopted in 2003. This specifies thearticulation of the institutionalmechanism intended to ensure a coherentimplementation and an optimal use of themain instruments put in place by thepublic authorities for the control ofenergy, namely:· The National Agency for the

Promotion and Rationalization ofthe Use of Energy (APRUE) whohas elaborated the NationalProgram for Energy control(PNME). This latter gathers manyprojects, actions and measures invarious fields. The actionsconcerning building energyefficiency with residential usageare: Thermal Rehabilitation, EnergyHigh Performance Dwellings, SolarHot Water, High PerformanceCooling and High PerformanceLighting. 80% of the costs related tothese operations will be providedby the National Fund for EnergyControl (FNME). In addition of TheIntersectoral Committee for EnergyControl (CIME), an advisory organplaced beside energy chargedMinistry to ensure energy controlpolitic animation and coordination.

4. Energy situation in Tlemcen

4.1. GeographyTlemcen is located in the extreme north-west of Algeria, exactly at 40km from theMediterranean Sea as the crow flies, at 63km from morocco frontier and at 550kmfar from Algiers (See Figure 1). It is at1°19’ west of longitude, and 34°56’ northof latitude and is backed by the flank oflalla Setti’s tray of (1200m of altitude).Locally, the agglomeration of Tlemcenextends over the territory of four

municipalities (Tlemcen, Mansourah,Chetouane and Beni Mester), covering anarea of 2736 hectares populated by morethan 236000 inhabitants namely520h/km² of density. The town site is asloped plan in South-North directionwith variable altitudes between 930 and550m (Ghomari, 2007).

Fig. 1. Tlemcen location: a strategic position in theNorth-West region (source: ANAT and DUC,

2005).

4.2. Energy situationAccording to the data of the year of 2014provided by the general leadership ofNational Society for Electricity and Gas(SONELGAZ) of Tlemcen (SONELGAZ,2015), this province has 252 208subscribers into electricity and 130 004into gas. The rate of actual electrificationof the province is of 98%. These datatestify a noticeable increase of energyconsumption from a year to another (seeFigure 2).

Fig. 2. Evolution of the energy consumption inTlemcen (source: Author according to

SONELGAZ, 2015).


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We notice that the number of subscribersincreases substantially between the firstterm of 2012 and the fourth one of 2013,both in electricity and gas (see Figure 3),the number is added of 30 140subscribers. While, the total specificconsumption increase of 3323kWh from2012 to 2013, pushed essentially by therise of the specific consumption of thefirst term of 2013 estimated of 65805kWhcompared with 2012. That can beexplained by the climate changes.

Fig. 3. Evolution of the number of electricity andnatural gas subscribers in Tlemcen (source:

Author according to SONELGAZ, 2015).

Fig. 4. Sunshine and radiation data on horizontalsurface in Tlemcen (source: Generated by ExcelTemplate by author according to O.N.M, 2008).

5. Tlemcen climateAccording to the Algerian climatic zoning(CNERIB, 1998), Tlemcen is classified inthe zone B. Being on a high altitude,Tlemcen’s climate can be cold to verycold in winter and warm to hot insummer, with north-west and south-westwinds through the year, and quite a goodamount of rain fall. The monthly data ofthe year 2008 of Safsaf station (at 592m of

altitude) in Tlemcen was collected fromthe National Office of Meteorology(O.N.M) (See Figures 4 to 7).

Fig. 5. Temperature data in Tlemcen (source:Generated by Excel Template by author according

to O.N.M, 2008).

Fig. 6. Humidity and rainfall data in Tlemcen(source: Generated by Excel Template by author

according to O.N.M, 2008).

0, 0

5, 0

10, 0

15, 0

2 0, 0

Jan Feb Mar Apr May Jun Jul Aug Se p Oct Nov Decm/ s

Spee d

Série1

Série3

ö

ö

ö ø ø ø ÷ õ ò ø ø ö ö

Fig. 7. Prevailing winds in Tlemcen (source:Generated by Excel Template by author according

to O.N.M, 2008).

6. Case study

6.1. Description of case studyThe case study is located in 1060dwellings residential district at the Eastof Tlemcen. It is an apartment with anarea of 70.38m² intends for division into


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living room and 2 bedrooms and a roomheight of 3.06m. It represents thedwellings constructed during the1980ies when Algerian politic wasoriented toward heavy prefabricationfor realization of the great wholes.Thermal and energy analysis isestablished on a middle cornerapartment, with two exposed facesoriented to South-east and South-westcompared with another one in the topcorner (see Figures 8 and 9). The plan inFigure 10 describes different spaces ofthe apartment.

Fig. 8. Exterior environment, 1060 dwellingsdistrict in Tlemcen (source: Author, 2015).

Fig. 9. Satellite view of 1060 dwellings district inTlemcen (source: Google Earth, 2012), the photo

spot of figure 8 is indicated.

6.2. Building techniquesThe buildings in 1060 dwellings districthave uninsulated and intight envelopes,and single-glazed windows. Table 1

shows the construction materials whichconstitute the building envelope.

Fig. 10 . Apartment plan (source: Author, 2015).

7. Static method

7.1. Simple calculation of calorific lossesaccording to Algerian housing building

regulationsFirstly, thermal losses of the case studyare estimated by simple state calculationaccording to DTR C3-2 of 10/12/97, andafter regulatory checking, the results inTable 2 have shown that the apartmentis not congruent and that the thermalcomfort is not insured. Thus to insurethe well-being of occupants and toreduce energy consumption, it must berehabilitated it thermally.

7.2. Design of a personalized strategySecondly, we have established a Lossesreduction strategy according to theRegulatory Technical Document citedabove through recalculating losses bytransmission, after reducing them byacting on:· Insulation of the outer walls from

exterior by adding a layer of glass wool


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of: 1, 2, 3, 4 and 5cm of thickness (as amineral insulation stem from recycling

of broken glass or from the raw material‘sand’ which is a local material);

Table 1. Building elements, 1060 dwellings district, Tlemcen (Source: Author according to DTR C3-2).Building e lement

Layer outsideinside

Material

Thickness(m

m)

Conductivity

W/m

.k

SpecificH

eatJ/kg.k

Density

Kg/m

3

Area

m2

Therm

alresistance

(R)

m²c°/W

Therm

altransm

ittancea(U

-value)W

/m²C

°

Ciment mortar 20 1.400 1080 2200 0.0143Prefab. Concrete

panel 130 2.500 1000 2400 0.052External wallsInternal Plaster

coating20 0.350 936 1000

80.85

0.0571

3.4083

Gravel 30 0.360 840 1840 0.0833Pure Bitumen 15 0.170 1000 1050 0.0882Bitumen, Felt

sheet 15 0.230 1000 1100 0.0652

Cement sandrender 50 1.000 1000 1800 0.05

Polyethylene (lowdensity)

0.2 0.35 2300 0.92 -

ExpandedPolystyrene

40 0.036 1404 20 1.1111

Polyethylene (lowdensity) 0.2 0.35 2300 0.92 -

Prefab.concretepanel 150 2.500 1000 2400 0.06

External Roof

Internal Plastercoating 20 0.350 936 1000

70.38

0.0571

0.6042

Internal Plastercoating

20 0.350 936 1000 0.057

Prefab.concretepanel

150 2.500 1000 2400 0.06

Cement sandrender

30 1.000 1000 1800 0.03

Intermediate floor

Granito tiles 20 2.100 936 2200

70.38

0.01

2.6525

Internal Plastercoating

10 0.350 936 1000 0.057

Hollowed Brick 100 0.560 936 1300 0.0178Internal partitionsInternal Plaster

coating10 0.350 936 1000

-

0.057

-

Ciment mortar 10 1.400 1080 2200 0.0286Prefab.concrete

panel130 2.500 1000 2400 0.052

Partitions face tonon-heated

spaces Internal Plastercoating 10 0.350 936 1000

14.77

0.0071

3.2499

Simple clearglazing, 3 0.1697Windows, glazed

doors Wooden windowframe,

wooden shutters30

11.860.3278

1.6260

Doors Wooden doors 30 3.725 0.5 2a: calculated by simple state calculation according to DTR C3-2 of 10/12/97


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· Insulation of the internal face of thepartition which separate theapartment from the non-heated spaceby adding a layer of cellulose woolpanel of:1, 1.5, 2.5, 3.5 and 4.5cm ofthickness (as a vegetable insulationstem from recycling newspapers orfrom the raw material ‘Alfa grass’which is a local material) associated to1.5cm of a plaster panel ;

· Renewing the external roof insulationby maintaining the same insulationmaterial with the same thickness (4cmof extended polystyrene), but byplacing the insulation layer over thecope layer not below it;

· Replacing simple glazing with doubleone (through only elimination of thepane divisors and maintaining thewindows frameworks and shutters).In addition of placement of weatherstrip of windows and doors to reduceair imperviousness;

· Placing of a window with doubleglazing in veranda and

· Putting awnings as shading devices.

Total thermal losses (D), thermal lossesby transmission (DT) and the thermalcharacteristics of the existing and theoptimum envelopes of the middle andthe top corner apartments are given inTable 2. In addition, the regulatorychecking to yield the apartment conformsto DTR C3-2.

7.3. Results and discussionThe Results have shown that the Algerianregulation –compared to regionalexperiences of Tunisia and Morocco-needs to be more thorough, because withfirst centimeter of insulation, the twoapartments become conform. While, justthe bold values of surface relatedtransmittance coefficient of external wallsverify the maximum allowed heattransfer coefficient at Oujda in Morocco

(located at regulative climatic zone ZT3)that has a similar climate with Tlemcen.

Although, Algeria was among the firstcountries that have elaborated itsregulatory framework and has taken partin the elaboration of the Thermal andEnergy Regulation of Maghreb’sBuildings (RTMB). This later constitutesthe starting point of Tunisian label.

Algeria must fulfill the lateness comparedwith other countries having implementedmandatory buildings thermal regulationsas Tunisia and Turkey. In fact, in thesetwo countries, the regulation has beenelaborated according to a global processfounded on a wide meeting with allparticipants and associated to theaccompaniment programs and theenhancement of the competence ofdesigners, operator and suppliers ofinsulation materials. Generally, theexperience of these countries shows thequality of elaboration process as a keyfactor of its efficient applicability.

8. Computer simulation

8.1. Base CaseStarting the DesignBuilder simulation,that uses the EnergyPlus dynamicsimulation engine (stemming fromrenowned software BLAST and DOE-2)to generate data performance (see Figure11), needs to draw plans and elevations ofthe apartment, for creating buildingvolumes to form the simulated apartmentas shown in Figures 12.

For this case, summer and winter weretaken as the studied cases. Density istaken 0.07 because the apartment isoccupied by 5 persons. The temperatureneeded for heating in winter was set to21°C (comfort condition in a housing areain Algeria). The lower temperature limit


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was set to 19°C. While, the lowertemperature for cooling in summer was

set to 25°C and the upper one limit 27C°.These inputs are constant for all cases.

Table 2. Results of thermal properties calculations' of envelope components, of recalculation of losses bytransmission (DT) before and after thermal rehabilitation and the regulatory checking (source: Author).

Outer wall insulation thicknessesThermal properties andlosses

Base caseNo-

insulation1cm 2cm 3cm 4cm 5cm

Comment

R Ext. Walls 0.1234 0.7435 1.0214 1.2987 1.5773 1.8553R Roof 1.5149 1,6551

Thermalresistance

(R)m²C°/W

R lnt Walls 0.0877 1.2667 1.3917 1.5167 1.8917 2.1417

U-value Ext.

Walls

3.4083 1.345 0.979 0.77 0.634 0.539

U-value Roof 0.6042 0.594U-valueWindows

1.626 1.3927

U-valueAve.a

2.0245 1.3898 1.0753 0.8957 0.7788 0.6972

U-valueWalls n.h.s. b

3.2499 0.7894 0.7185 0.6593 0.5286 0.4669

Thermaltransmittance

(U-value)W/m²C°

U-valueAve. n.h.s. c

3.7568 0.8651 0.7986 0.7431 0.6206 0.5627

Just the boldvalues verify

themaximum

allowed heattransfer

coefficient ofexternalwalls atOujda in

Morocco thathas a similarclimate with

Tlemcen.

Coefficient oftemperature

reduction (Tau)

0.35 0.60 Given by theDTR

DS d 300.98 131.39 101.80 84.90 73.90 66.22Dli e 60.19 26.28 20.36 16.98 14.78 13.24

Dn.h.s. f 21.89 5.96 5.56 5.22 4.49 4.14DT 383.07 163.62 127.71 107.10 93.17 83.61

DR g 72.89 71.35 71.18 70.84 70.50 70.16

Thermallosses ofmiddle

apartment(W/°C)

D 455.96 234.98 198.90 177.94 163.67 153.76Reference

losses (W/°C)Dref. 163,42

Regulatorychecking

DT>1,05 x Dref = 171.59W/°C

DT <1,05 x Dref = 171.59 W/°C The boldvalues verifythe formula

DS 343.5 171.73 141.98 124.76 113.43 105.43Dli 68.7 34.35 28.40 24.95 22.69 21.09

Dn.h.s. 21.89 5.96 5.56 5.22 4.49 4.14DT 434.01 212.04 175.93 154.93 140.61 130.65DR 72.89 71.35 71.18 70.84 70.50 70.16

Thermallosses of top

cornerapartment

(W/°C)D 506.9 283.39 247.11 225.77 211.11 200.81

Referencelosses (W/°C)

Dref 226.76

Regulatorychecking

DT>1.05 x Dref = 238.1W/°C

DT <1.05 x Dref = 238.1 W/°C The boldvalues verifythe formula

a. Average of surface related transmittance coefficient [W/m².°C]; b. Surface related transmittancecoefficient of parti tion in touch with non heated spaces; c. Average of surface related transmittance

coefficient of parti tion in touch with non heated spaces; d. Surface losses through the current parts ofpartitions in touch with exterior; e. Losses through the liaisons; f. Losses through the partition in touch

with non heated spaces; g. Losses by air renewal.


144

Fig. 11. DesignBuilder diagram (source:DesignBuilder© Software, 2009).

Giving the data of personal loads insideeach volume at certain times of the dayaccording to the relationship betweennumber of people and the activity thatthey are doing, the values were appliedfrom (ASHRAE, 1997). Occupationpattern and resulting internal loads offive persons is estimated according toTable 3.

Fig. 12. 3D simulation model of the studiedapartment and building (source: Author, 2015).

All cases have been simulated with threedifferent ventilation rates in Air Changeper Hour (ACH) assumed when thebuilding is closed because of: firstly thedifference of infiltration over timedepending on changing winds speed and

Table 3. Internal loads from five occupants andappliances (source: ASHRAE, 1997).

Vol

ume

Hou

rs

Inte

rnal

load

s(W

h/h)

Comment

22-06 300 3 persons sleeping(children)1

10-11 270 Housecleaning for 1 hour22-06 200 2 persons sleeping10-12 270 Housecleaning for 1 hour214-15 75 1 persons takes a nap07-08 100 5 people passing through10-11 270 Housecleaning for 1 hour12-13 80 Arrival after work, etc

3

18-19 100 5 people passing through

06-07 100 Making breakfast for ½hour

07-08 550 3-5 people eating andsitting for less than 1 hour

10-11 270 Housecleaning for 1 hour10-12 180 Making lunch

12-13 440 4 people eating andsitting for 1 hour

16-17 100 Making cafe for ½ hour

17-18 330 3 people eating andsitting for less than 1 hour

19-20 180 Making supper

4

20-21 550 5 people eating andsitting for 1 hour

10-11 270 Housecleaning for 1 hour5

18-19 265 1 Person showering for ¼hour

08-09 105 1 person sitting for lessthan ½ hour

10-11 270 Housecleaning for 1 hour15-17 378 2-3 guests sitting

6

19-21 400 Living room occupationincl watching TV


145

direction; secondly, the user behavior(opening/closing windows). These ratesshould roughly correspond to untight (2ACH), rather tight (1 ACH) and verytight (0.5 ACH) windows.

In summer, windows are most of the timeopen, but during winter, they are openjust for housecleaning, while windowsare open during autumn and spring days.When the windows are open, a rate of 10ACH is supposed (Rosenlund et al., 2005;Šadauskiene, 2016). The energy usepresented in results below depends onequipment’s coefficient of performance(COP) (see Table 4).

Table 4. Ventilation rates in Air Change per Hour(ACH) (source: Author).

Volume HoursVentil-

ation(ACH)

Comment

Autumn, 1- 31 OctoberSpring, 1 April-31 May

1-6 08-2020-08

Opena

Closedb

Winter, 1er November – 31 March10-11 Open Just for

housecleaning

1-611-10 Closed

Heated at 21 °Cby a spot heating

of natural gas(COPc=0.87)

Summer, 1er June – 30 September20-9 Open Free cooling

1-69-20 Closed

Air-conditionedat 25 °C

No cooling issupplied, but it is

arranged byautonomouselectric air-

conditioners(COP=3.06)

a: ‘Open’ means 10 ACH; b: ‘Closed’ means 0.5-1and 2 ACH depending on case, see results;

c: Coefficient of performance

Domestic Hot Water is ensured by anautonomous gas water heater having aCOP of 0.85 to heat a daily water volumeof 50l/day/per. Next, identifying

materials used in the studied buildingelements, those are already presented inTable 1. As well as, the optimizedbuilding elements as shown in Table 5.

The hourly climate data of Tlemcenbased on thermal reference yeargenerated by the software Meteonorm(version 5.1.) was applied to thebuildings parameters for the whole yearand in some cases for typical days ofJuly and January. In the passive case theapartment is considered as a multi-zone, but in the active one, zones aremerged onto a single zone because thereis one source of heating.

9. Results analysisAfter the simulation and the confirmationof the data, the calculations of heating,cooling loads and CO2 emissions,together with temperatures of apartmentand volumes were then run by theDesignBuilder program to give thefollowing results.

9.1. Active case results: energy efficiency andenvironmental impact

The yearly heating and cooling demandas well as CO2 emissions for the baseline–the existing non-insulated apartment inthe middle corner of the building withtwo exposed faces and single-glazing- isshown in Figure 13 for three differentminimum ventilation rates. The untightactual case is positioned in ‘class 7’ ofTunisian label and in ‘level D’ of the BBClabel which has bad energyperformances.

9.1.1. Effect of ventilation reductionThe potential of heating and coolingenergy saving by reducing ventilation isnoticeable. The tightest apartment has anenergy use of about 62% of the untightone and reaches the ‘class 5’ of theTunisian thermal and energy regulation


146

of new buildings (RTETBN) as minimallimits. The CO2 emission reduction isabout 22% in the tight apartmentcompared to the untight one, pushing theenvironment ranking from ‘level F’ to‘level E’.

Fig. 13. Yearly heating, cooling and total demandtogether with CO2 emissions per sq. m of a non-insulated apartment (middle corner of building)

with simple glazing. This case represents thebaseline, existing building (source: Generated by

Excel Template by the author according tosimulation results using DesignBuilder©

Software, 2016).

9.1.2. Insulation effectPlacing the insulation layers in thestudied apartment’s envelope, (see Figure14) can save about 41% of heating and

cooling energy in the untight apartment,about 64% in the medium and 57% in thetight one. Pushing the ranking to ‘class 1’in Tunisian label and to ‘level C’ in BBClabel, saving about 32% of energy in theuntight apartment, 38% in the mediumand 41% in the tight one. Also, reachingthe ‘level D’ of environment etiquette inthe tightest apartment that can save 43%of CO2 emissions compared to the untightbase case.

Fig. 14. Yearly heating, cooling and total demandtogether with CO2 emissions per sq. m of an

insulated middle corner apartment with singleglazing (source: Generated by Excel Template bythe author according to simulation results using

DesignBuilder© Software, 2016).

Table 5. Summary of the energy efficiency measures (source: Author).Measure Description Area/Length

(m²/ml)Total

U-value(W/m²C°)

Additionalbenefits

Investmentcosts (€ )

Life cycleduration

(year)Weather strip Strip of felt 9.11 - Reduce the

infiltration6.21 10

Façadeinsulation

External-GlassWool Pannel-3cm

106.78 0.770 6717.6 >25

Partitioninsulation

Internal-moderately rigid

cellulose wool

27.36 0.745 321.13 25

Roofinsulation

Inverted-EPS 89.85 0.593

Reduce thethermal bridge

622.13 >25

Window panechange

3/6/3 3.159 283.12 25

Windowssizex1.5

3/6/3 PVC 17.79 3.159 4314.58 25

Glazedveranda

3/6/3 PVC 3.2 3.159

Reduce airinfiltration

776.26 25

Solarprotection

Awning Line: 1.5way out: 0.8

- - 1260.31 10


147

The effect of insulation is thus greater ifventilation is kept low. Combiningreduced ventilation and moderateinsulation can give as much as 73%heating and cooling energy saving.

9.1.3. Effect of double glazingThe effect of double glazing, compared tosingle one, for the insulated case is 42% ofenergy saving in the untight apartmentand about 59% in the tight one. Thecombination of the two precedentparameters with the double glazing cansave more than 74% of heating andcooling energy and more than 59% oftotal energy including domestic hot waterand lighting energy (see Figure 15).

Fig. 15. Yearly heating, cooling and total demandtogether with CO2 emissions per sq. m of an

insulated middle corner apartment with doubleglazing (source: Generated by Excel Template bythe author according to simulation results using


For the uninsulated apartment, thecorresponding saving is only 2%. But it isabout 39% in the tightest one comparedto untight base case, to achieve theminimum limits of the RTETBN 2008.And the ‘level C’ of BBC label savingmore than 31% of energy in the tightapartment compared to untight base case.Combination of double glazing withreduced ventilation have also a low effecton the environment label, staying only in‘Level E’ and reducing about 23% of CO2

emission compared to the untight basecase (see Figure 16).

Fig. 16. Yearly heating, cooling and total demandtogether with CO2 emissions per sq. m of a noninsulated middle corner apartment with doubleglazing (source: Generated by Excel Template bythe author according to simulation results using


9.1.4. Orientation effectActual case facades are oriented to thesouth-east and south-west, which cangive an absolute gain of solar energyduring winter. But, it can also cause a realoverheating during summer.

It has been found, that orienting facadestowards the north-east and north-westconducts to a supplementary use of 23%of energy for heating in the untight case,30% in the medium and 35% in the tightone; and to an energy saving of 11% forcooling in the medium and tight cases.

By orienting facades towards the north-east and south-east, the results show asupplementary use of 13% of energy forheating in the untight case, 17% in themedium and 20% in the tight one; and anenergy saving between 12-13% forcooling in the three cases.

And the results show that by orientingfacades towards north-west and south-west, a usage of more than 10% of energyfor heating in the untight apartment, 13%in the medium and 16% in the tight oneare noted; and an energy saving about 16-17% for cooling in the three cases (seeFigure 17). So, we can conclude thatorienting the building towards the north,the east and the west is not efficient and


148

that the original case oriented to south isthe best orientation for energy saving.

Fig. 17. Comparison of yearly heating, coolingand total demands together with the CO2

emissions per sq. m of base case (non insulated,simple glazing in middle building), placed in the

three other orientations (source: Generated byExcel Template by the author according tosimulation results using DesignBuilder©

Software, 2016).

All cases above have displayed threecases of ventilation rates: high, mediumand low. From these cases, it can beconcluded that reducing the ventilationto 1/2-1/4 generally saves from 38% to75% of energy.

9.1.5. Effect of another envelopes’ inertiaIf we compare the studied apartmentenvelope -constructed using heavyprefabrication- with another existing oneusing a reinforced concrete supportstructure and a hollow brick filling wall,we note that the positive influence of thematerials inertia used in this later (usingthe red-hollow-brick in double walls of 10and 15cm separated by 5cm of air gap inthe outer wall, having a U-value=1.344W/m².K and the same red-hollow-brick of 15cm in the wallseparating the apartment from the non-heated space, having a U-value=2.381W/m².K and 16cm of concrete-hollow-blocks and 4cm of reinforcedconcrete in the roof and the ceilinghaving a U-value=0.439W/m²K) is alsoevident. This saves more than 34% of

heating and cooling energy in themedium apartment and 50% in the tightone compared to the untight case havingthe same envelope.

But, comparing it with base caseenvelope, heating and cooling energysaving is about 31% in the untight, 39% inthe medium and about 45% in the tightapartment. It also saves about 55-66%compared to the untight base case.Whereas, CO2 emissions level, in thethree minimum ventilation rates, isalways in ‘level E’, but it saves about 22-23% of CO2 emissions in medium andtight apartments compared to untight oneand 20-40% compared to untight basecase (see Figure 18).

Fig. 18. Yearly heating, cooling and total demandtogether with CO2 emissions per sq. m of a noninsulated apartment with a reinforced concrete

support structure and a hollow brick filling wallenvelope (middle corner of building), with simpleglazing (source: Generated by Excel Template bythe author according to simulation results using


9.1.6. Effect of apartment locationBy placing the baseline apartment in thetop corner position we note that theuntight apartment has a very bad level ofenergy performance: ‘class 8’ of theTunisian label and ‘level E’ of BBC label.The tight non insulated apartment at topcorner has a supplementary heating andcooling energy use of about 10% of thetightest base case in middle floor/corner,recorded mainly by the heating energythat requires 15% more than the middle


149

floor/corner apartment (see Figure 19).While, an insulated and double glazedapartment at the corner of the top floorconsumes for heating and cooling about55kWh/m² year, having a supplementaryneed of energy of 19% more than acorresponding middle apartment. So, thetop corner or top floor apartments requireadditional insulation because of thecalorific losses of roof.

Fig. 19. Yearly heating, cooling and total demandtogether with CO2 emissions per sq. m of a non

insulated top corner apartment with simpleglazing (source: Generated by Excel Template bythe author according to simulation results using


9.1.7. Effect of increasing the sizes ofsouth-facing windows

Another way of further reducing theheating need is to increase solar gains. InFigure 20, the size of the south facingwindows of the insulated double glazedapartment is increased to one and a half.Only the low-ventilation apartment iscalculated. Its heating need issubstantially reduced compared to thebaseline case saving about 90% of heatingenergy namely about 10 times acorresponding tightest base case andmore than 2 times less than thepassivhaus requirements. But, it savesjust 14% of cooling energy compared tothe tight baseline case. While, this savesmore than 74% of heating and coolingenergy compared to the untight basecase. And 58% compared to the tight one.And about 59% of total energy includingdomestic hot water and lighting energy

compared with the untight base case and41% compared to the thight one. Inaddition, it saves 43% of CO2 emissionscompared to the untight base case and27% compared to the tightest one.

Fig. 20. Comparison of yearly heating, coolingand total demands together with the CO2

emissions per sq. m of tight base case (noninsulated, simple glazing in middle building),

with an insulated, double glazed apartment withincreasing of south facing windows size to 1 and½ (source: Generated by Excel Template by the

author according to simulation results usingDesignBuilder© Software, 2016).

9.1.8. Effect of glazed verandaOne of the common actions of retrofittingapartments in Algeria is placinggreenhouses in the kitchen verandas toincrease the kitchen area and to protectthe veranda from weather. But is itbeneficial for the interior climate? TheFigure 21 shows that heating energysaving is estimated more than 85% in aninsulated apartment with double glazingand glazed veranda compared to the tightbase case and the energy saving ofcooling is more than 15%. This same casesaves 86% of heating energy and about20% of cooling energy compared to a noninsulated apartment with simple glazingand a glazed veranda. While, this laterhas a supplementary need of cooling upto 6% than the tight base case.

To contend the overheatingphenomenon during summer, twodispositions, in addition of increasing


150

ventilation, can be taken: the glazedpanels can be totally folded up, in orderto recreate a simple balcony; besides,these greenhouses must carry shadingdevices to protect them from incidentsolar radiation during summer. So,placing greenhouses using single glazingin the kitchen verandas of a noninsulated apartment is not efficient.However, it consumes more energy.

Fig. 21. Comparison of yearly heating, coolingand total demands together with CO2 emissionsper sq. m of the tight base case with greenhouseand an insulated middle apartment, with double

glazing and greenhouse in kitchen balcony(source: Generated by Excel Template by theauthor according to simulation results using


9.1.9. Effect of shading devicesTo avoid overheating in summer, manysuggestions of shading device, withdifferent dimensions, have beensimulated (louvers, overhangs and fins ortheir combination). The most efficientcase is the one to which 65cm moveableoverhangs are added, in addition ofshading that is given from the depth ofwindows in an insulated middle cornerapartment with double-glazing andgreenhouse. Assuming that theventilation is kept at a minimum, coolingload decreases to reach more than36KWh/m² yearly. While, heating loadreach less than 10KWh/m² yearly,instead of more than 63KWh/m² yearlyto heat a non-insulated tight middle

corner apartment with single glazing.Total energy saving is estimated to 57%compared to tight base case and to morethan 73% compared to the untight one.While, it saves 27% of CO2 emissionscompared to tight base case and about39% compared to untight one (See Figure22).

Fig. 22. Comparison of yearly heating, coolingand total demands together with CO2 emissionsper sq. m of tightest base case and an insulated

middle apartment, with double glazing andshading device combined to glazed veranda(source: Generated by Excel Template by theauthor according to simulation results using


9.2. Economical Rationality analysis resultsAfter analyzing carefully EE and EIcriteria, we have established an economicimpact study according to the methodexplained in (Missoum et al., 2014). It hasbeen found that only the actions relatedto: changing the windows panes, placinga window in veranda and solarprotections are cost-effective, to recordpayback times of 7, 15 and 22 yearsrespectively. In addition to the caulkingof windows and doors that has low cost.While, investment cost of: insulation andchanging windows are very high. Thekey arguments are the actual prices ofinsulation materials in the Algerianmarket (see Table 5), and the energyprice! It is the less expensive in Africa,even the undeveloped countries pay thereal price, because, it is conventionalized


151

by the Algerian state. It is fixed basing onsocio-economic criteria (with about7000€/household as income level).Subventions are indirect through areduction applied on benefits ofproduction societies under state control(SONELGAZ). Energy prices in Algeriaare blocked since the Decision D/06-05/CD of 30 May 2005 with0.278DZD/kWh=0.0024€/kWh fornatural gas and4.179DZD/kWh=0.0356€/kWh forelectricity.

9.3. The passive case results and analysis:Thermal comfort

9.3.1. Before rehabilitationPassive results of actual case in Figures23, 24 and 25, when no energy at all wasused for heating and cooling, show thatoperative temperature in winter varybetween 10.94°C and 13.33°C. Thistemperature is lower than comfort zonewhich vary between 21°C and 25°C(considered in the DTR.C3-2). Therefore,comfort is not yet insured. Thus, insummer, thermal comfort is also notinsured, because operative temperaturesvary between 28.03°C and 33.01°C.

9.3.2. After rehabilitationAfter improving apartment envelopeelements as it has been explainedpreviously in Table 5, the results showthat losses after rehabilitation are lowerthan the actual case ones; temperature isimproved in winter as in summer.Improvement of internal operativetemperature in winter has reached17.65°C and 18.52°C and between 28.26°Cand 31.18°C in summer. Very helpful heatand cooling gains which will improvethermal comfort and decrease energyconsumption and CO2 release, but whichare not sufficient to achieve thermalcomfort zone. Nevertheless, an importantinsulation can cause overheating in

summer, though the ventilation must berightly studied.

Fig. 23. Operative tempera ture in the apartmentbefore and after the thermal rehabilitation in

winter (12/01) and in summer (21/07) (source:Generated by Excel Template by the author

according to simulation results usingDesignBuilder© Software, 2016).

Fig. 24. Operative tempera ture in volumes beforeand after thermal rehabilitation in 12/01 (source:

Generated by Excel Template by the authoraccording to simulation results using


Fig. 25. Operative tempera ture of volumes beforeand after thermal rehabilitation in 21/07 (source:

Generated by Excel Template by the authoraccording to simulation results using



152

10. ConclusionIn this article, a sustainable solution forthe optimization of EEP in the existinghousing in Tlemcen is investigated. Toachieve this multi-objective approach asin the study of Gossard et al. (2013), amulti-criteria assessment of passive EEMhas been performed in order to retrofit amulti-storey apartment envelope. Theresults, confirmed by the study’s findingsof Mikučionienė et al. (2014), Ouahab(2015), Liu et al. (2015), Lawania andBiswas (2016) and Ortiz et al. (2016), haveshown that energy saving is the key of acontribution effectively measurable tosustainability and climate protection.

These results have also confirmed thenecessity of thermal rehabilitationtranslated by the rapidly decrease of theannual energy requirements with the firstfew centimeters of insulation. That

conducts to the obligation of applying thethermal regulation. Together with, thedevelopment of this latter in order toelaborate specific norms to differentclimatic zones and to establish Algerianproper sustainable design guidelineappropriate to the socio-economiccontext, which is consistent with the goalof the study of Huang et al. (2012). In thistopic, the need of a consolidated Algerianenergy efficiency politics combining, inthe same time, tariffs reform andconsumption reduction as recommendedby Ouyang et al. (2011), in order to limitthe increase in the invoice for thepopulation, especially for the mostdestitute is a necessity. The energypricing affects the profitability of energyimprovements. And a tariff blocking, asin the Algerian context, can limitartificially the investment alternatives inthese improvements.

Table 6. Matrix of different energy-saving actions. Tentative savings for typical multi-storey dwellings(middle of building) in the Tlemcen climate, based on the computer simulation study (source: Author).

Suitable forCost level Retrofit

by

Action

Typicalheating

andcoolin

gsavin

g

Tunisian

EnergyC

lass

Typicaltotal

saving(including

ESC+

lightingenergy)

BB

CEnergy

Level

Typical

CO

2Em

issionssavin

g

BB

CEnvironm

entLevel N

oLow

MediumH

igh

New

building

User/T

enant

Ow

ner/M

anager

Ventilation reduction(keeping closed)a 37-75% Class

1 30-59% LevelB 15-44% Level

D X X X

Weather stripping ofwindowsa 37-75% Class

130-59% Level

B15-44% Level

D X X X X

Larger south windows(sizex1,5 , 2-glass)a*

74% Class1

59% LevelB

43% LevelD

X X

Moveable shading devicecombined to glazedveranda (2-glass)a*

73% Class1

58% LevelC

39% LevelD

X X X

Envelope insulationa 64-73% Class4-1

51-58% LevelC

24-43% LevelE-D

X X X

Double-glazinga 39% Class4

31% LevelC

25-44% LevelE

X X X

Glazed veranda (2-glass)a*

56% Class1

40% LevelC

38% LevelD

X X X

Double-glazingb 26-39% Class7-5 21-31% Level

D-C 23% LevelF-E X X X

a. Moderate insulation; b. No-insulation; *. For low ventilation ra tes.


153

Therefore, we try to assign an order ofpriority of actions to lead in short,medium and long term, using amultitude of more or less advancedtools, according to the potentials ofenergy saving and those of CO2

emissions reduction, to improve EEP inexisting dwellings together withconception of new ones, given by thelimited parametric study used byBelpoliti and Bizzarri (2015), indicated inTable 6.

Appendix A

Table A.1. Benchmarking of international thermal regulations and existing energy saving labels andcertificates (source: Author according to (ANME, 2010; Charlot-Valdieu and Outrequin, 2011; Bertucci and

Ogier, 2010)).kWh/

m².year

Labels andreferential

Objectives of consumption Certification/promotion

Criteria taken intoaccount

Concernedequipments

80-250 RTa 2005(Decisions : May2006 for the new,May 2007 for the

renovation)

80 to 250kWh/(m². y)according to the climatic

zones.

Thermal insulation,introduction of thebioclimatic and therenewable energy.

231 PH and Eb

certificationThey are reserved to ownersof multi-story buildings and

can covering the co-ownership field. To achieve

this certification, energyconsumption must be less

than 231kWh/(m2.y).72-225 HPEd /HPE EnRe

(Decision: 2007for the new),

HPE renovation

(Decision :September 2009

for therenovation : forbuildings built

after 1948)

-RT2005 -10%

For the THPE EnR, 50% ofthe heating energy must bederived from the biomass orfrom a heat network usingmore of 60% of renewable

energy.

HPE renovation (high energyperformance renovation):

maximum consummation of150kWh/(m². y), according

to the altitude and theclimatic zones.

56-200 THPEf / THPEEnR (Decision :

May2007)

RT 2005 -20% (-30% for theTHPE EnR)

Qualitel- CerqualPatrimoinec

80-150 PC ; PC and Eg Performance levels requiredare:

- 1 Star: minimal techniquesrelated to insulation (roof or

façade, double glazing ;

Qualitel- CerqualPatrimoine

These new certificationsconcern six topics:

Energy performance;

Heating/coolingSystem

Production ofsanitary hot

water.

+ auxiliaries andlighting forEffinergie

Expressed asprimary energy.


154


Ogier, 2010)).kWh/

m².year




Concernedequipments

- 2 Stars realization of a seriesof works with a minimal

performance;

- 3 Stars low than150kWh/(m². y) of primary

energy (climatic zones,altitude);

- 4 Stars low than80kWh/(m². y) of primary

energy

accessibility and usagequality (senior citizen-handicapped persons);

health (sanitary quality)and security (fire); close

and cover (materialchoice, facade, cover

and body protection);equipment and thecomfort of common

parts (elevator, domesticwastes areas, lighting);

acoustic.

105-125 RTEBNTh 2008 The regulation must targetthe class 5: 105-125kWh/(m²y) in 2008 according to the

climatic zones.

85-95 RTEBNT 2010 The regulation must targetsthe class 3: 85-95kWh/(m². y)

in 2010 according to theclimatic zones

RTEBNT 2008 -25%

Thermal insulation,introduction of the

bioclimatic, economicallighting and the

renewable energy.



40-125 BBCi(Decision:May 2007 for the

new),

BBC renovation

(Decision:September 2009

for therenovation : forbuildings built

after 1948)

- In the dwellings, the energyconsumption vary from 40 to70kWh/(m². y), according tothe altitude and the climatic

zones.-BBC renovation (low energy

consumption buildingrenovation): maximum

consummation of80kWh/(m². y), according tothe altitude and the climatic

zones.

For the tertiary, the globalenergy consumption =

RT2005 -50%.

Certivéa- Cerqual –Céquamij- Promotéleck.

Referential positionedby Effinergie®l.

Criteria: thermalinsulation, renewable

energy, Bioclimatic, airimperviousness,

ventilation, globalquality of the building



water.



<75 RTEBNT 2012 The regulation must targetsthe class 1:<75kWh/(m². y)

in 2012 according to theclimatic zones

RTEBNT 2008 -40%

Thermal insulation,introduction of the

bioclimatic, economicallighting and the

renewable energy.




155


Ogier, 2010)).kWh/

m².year




Concernedequipments

40-65 RT 2012(Decisions : April2013 for the new,January 2013 forthe renovation)

40 to 65kWh/(m². y)according to the climatic

zones

Thermal insulation,introduction of thebioclimatic and therenewable energy.



water.



40-80 Minergie®m

(Switzerland1996)

Primary energy for thedwellings:

- New: between 40 to45kWh/ (m² y);

- Renovation : 60kWh/(m².y).

30 Minergie P®(plus) (2003)

Primary energy : new :30kWh/(m². y).

30 Minergie ECO®(2006)

Destination to theadministrative and locative

buildings, the schools.

Retake Minergie® etMinergie P® with healthyand ecological materials.

Prioriterre (Haute-Savoie)

Criteria: airimperviousness (save

Minergie®), softaeration, renewableenergy, limitation of

thermal bridges.

+ equipments andeconomical lighting for

Minergie P®

Minergie Eco: daylighting, muffler

protection, air quality,construction quality.

Heating/coolingsystem


water

Electricity forventilation

The calculationinclude the

production ofphotovoltaic

lighting

15 Passivhaus®n

(Germany 1990)

Maison passive(France 2007)

Gross heating requirement:maximum of 15kWh/(m². y)(whatever been the altitude

and the climatic zone).

Total primary energy,equipments included:

maximum of120kWh/(m². y)(*).

La Maison passiveFrance (LaMP®).

Criteria: airimperviousness,

insulation, suppressionof thermal bridges,orientation to sun,ventilation, high

performance householdappliances.

Heating/coolingsystem

Ventilation

(*) + Productionof sanitary hot

water

All equipment inthe house

a. French thermal regulation; b. Heritage Houzing « Patrimoine Habitat », Heritage Houzing andenvironment « Patrimoine Habitat et Environnement »; c. Is a filial of Qualitel society ; d. High energyperformance; e. Renewable energy; f. Very high energy performance; g. co-ownership Heritage «Patrimoinecopropriété» and Heritage co-ownership environment «Patrimoine copropriété environnemen» ; h. Tunisianthermal and energy regulation of new buildings; i. Low consumption building: Bâtiment basse


156

consommation: the label BBC, the environment label: is a French label; j. Quality Certification on individualhouses, affiliate of CSTB and Qualitel society, created in 1999, is commissioned by Afnor Certi fication, ownerof mark “NF Maison individuelle » and « démarche HQE® » for existing buildings; k. Promotelec is asociety aiming to promote the electricity usage in the residential building and small tertiary; l. is a societyaiming to “promote, in a dynamic way, the low energy consumption buildings in new and in renovation andto develop in France an energy performance referential of new or existent buildings. BBC label is created bythis society in 2007; m. The Prioriterre society delivered the Minergie label stem from the Swiss labeléponyme; n. Is a German norm which has been initiated in 1989 by Wolfgang Feist (Passivhaus Institutedirector), it is the best criterion of performance all over the world for the economy of energy. Its limits ofenergy consumption for heating and cooling are 80% less than for the Low Energy House and about 6 timesless than that is planned by the French thermal regulation (RT2000) and 4 times less than the Germanregulative value.

AcknowledgementWe thank “Materials and ConstructionTechnologies Institute” at « RoyalScientific Society » in Jordan, to havemade available to us: the DesignBuildersoftware (Trial version of 30 days)version 2.2.4.001, EnergyPlus softwareversion 4.0.0. and Meteonorm softwareversion 5.1.

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Received: 7 January 2017 • Revised: 20 January 2017 • Accepted: 23 January 2017

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