Energy Efficiency Retrofitting of Residential Buildings Case study: Multi-Family apartment building in Tripoli, Lebanon

Energy Efficiency Retrofitting of Residential Buildings Case study: Multi-Family apartment building in Tripoli, Lebanon Sabsaby Yathreb 

Abstract— Energy efficiency retrofitting of existing buildings was long ignored by public authorities who favored energy efficiency policies in new buildings, which are easier to implement. Indeed, retrofitting is more complex and difficult to organize because of the extreme diversity in existing buildings, administrative situations and occupation. Energy efficiency retrofitting of existing buildings has now become indispensable in all economies— even emerging countries—given the constraints imposed by energy security and climate change, and because it represents considerable potential energy savings. Addressing energy efficiency in the existing building stock has been acknowledged as one of the most critical yet challenging aspects of reducing our environmental footprint on the ecosystem. Tripoli, Lebanon chosen as case study area is a typical Mediterranean metropolis in the North Lebanon, where multifamily residential buildings are all around the city. This generally implies that the density of energy demand is extremely high, even the renewable energy facilities are involved, they can just play as a minor energy provider at the current technology level in the single family house. It seems only the low energy design for buildings can be made possible, not the zero energy certainly in developing country. This study reviews the latest research and experience and provides recommendations for deep energy retrofits that aim to save more than 50% of the energy used in a typical Tripoli apartment building.

Keywords—Energy-efficiency, Existing Building, Multifamily Residential building, Retrofit. I. INTRODUCTION

F

more than three decades, Lebanon suffered from many problems in the energy sector and espically in the electric power sector. Lebanon is a country largely devoid of fossil energy. The energy sector structure did not change in 2009; almost 98 % of the primary energy needs were imported. These imports are mainly based on oil by-products [11]. In 2009 the total supply in primary energy reached 6,735 kTOE, an increase of 3.5 % yearly since 2000 (Fig. 1). Gas represented 26%, gas oil 42% and fuel oil 20%, i.e. almost 88% of the total for only these three products. In 2009, the national energy bill reached 3,134 million, which represents more than 12% of the GDP (Gross domestic product). It has multiplied by three since 2000. This is due to the combined effects of the rise in the oil prices, OR

Sabsaby Yathreb is with the Faculty of Architectural Engineering, Beirut Arab University, Debbieh, 115020, Lebanon (e-mail: ar_yathrebsabsaby@ hotmail.com).

the growth of energy demand per capita and the demographic growth. Despite the end of the civil war in the beginning of the 90's and the billions of dollars invested in the electricity sector, still there is a severe rationing applied on all the country: 3 hours a day in the administrative area of the capital, Beirut, and 24 hours over each 48 hours outside this area (Fig. 2) [7].

Fig, 1 Evolution of primary Energy total supply (1992-2009) [11].

Fig. 2 Beirut and other region households' daily blackout.

The analysis of the final energy budget shows that the transportation sector consumes the most energy, followed by the residential-tertiary sector (Fig. 3). The industrial sector remains the less consuming as it is based on transformation industries with weak energy content [11]. Globally, the building sector is estimated to be responsible for more than one third of energy consumption, making in the biggest single contributor to total energy consumption [2]. The increased population, housing stock and better living standards will increase energy demand in the building sector. Since more households are using electrical appliances such as refrigerators, washing machines, and air conditioners, last of which the main cause of the rapid electricity demand increase. In addition, growing prosperity causes an enormous demand for small air conditioning units and an increase in power consumption in existing buildings. Energy consumption in existing buildings should increase because of aspirations to greater comfort. Low or even no requirements at all on energy consumption in new construction will lead to

disproportionately high levels of energy consumption in upcoming decades. In Asia, blindly copying European or North American architecture and construction techniques leads to inadequately high consumption rates. This sets the wrong tone in the pioneering spirit of these emerging markets [1]. This increase will “waste energy” (for heating and air conditioning) because of the poor thermal condition of most existing buildings. It is therefore necessary to implement an energy efficiency-retrofitting program for existing housing and tertiary buildings. However, at the current market prices, the payback time for this operation is not very attractive for building owners, even if the interest for society is clear. Therefore, an incentive system for thermal retrofitting investments needs to be set up in the form of subsidies or soft loans. Consulting the partners concerned should make it possible to choose the best solution. Eventually making “thermal renovation” mandatory for all existing buildings containing heating and/or air conditioning systems must be envisaged [8].

saving energy and lowering utility costs exists with multifamily residential buildings. Multifamily residential buildings are a type of housing where multiple separate housing units for residential inhabitants are contained within one building. In an attempt to fill a significant gap in baseline information, "Amara Apartment building" have been studied to analyse the residential consumption patterns in the urban environment in Tripoli, Lebanon. The aim of the paper is to reduce the energy consumption of existing residential buildings in TripoliLebanon- by improving the thermal performance of residential building envelope. 6% 26% 67%

1%

Independent house villas of more than one floor

Fig, 4 Distribution of primary residences by type of residence in 2007 [4]. Fig. 3 Repartition of end-use energy by sectors [11].

II. ENERGY EFFICIENCY RETROFIT IN MULTI-FAMILY APARTMENT BUILDINGS

Therefore, what we lack is a comprehensive strategy for this sector taking in account the different energy sources, traditional and renewable, combined with Energy Efficiency measures to solve definitely this problem in the existing residential building sector. Limiting the growth of electricity consumption will not only have economic and environmental benefits, it will also support energy security and a cleaner environment. On a national level, this will free up financial resources for sectors in need, such as health and education. On an individual level, it will ease the household budget. The European Union (EU) has named energy efficiency (EE) as one of the best ways to foster energy security in the long term, and to create jobs [2]. Most of the developed countries are implementing building energy regulations such as energy standards, codes etc., to reduce building energy consumption. The position of developing countries with respect to energy regulations implementation and enforcement is either poorly documented or not documented at all. In addition, there is a lack of consistent data, which makes it difficult to understand the underlying changes that affect energy regulation implementation in developing countries. In that respect, this paper survey the energy consumption in a typical Lebanese residential building, in the aim to present typical energy efficiency solutions. In fact, the primary residences in Lebanon are distributed into the following types of residences: 67.0% apartments in independent buildings, 26.0% independent houses, 6.0% apartments in a residential project and 1.0% as "villas consisting of more than one floor. "Improvised residences did not make up a significant percentage of the total number of primary residences (Fig. 4).One the largest opportunities for

Multifamily buildings represent a significant opportunity for major energy savings for a number of reasons. First, there are almost the typical prevalent residential building in the Lebanon that is not constructed to any energy efficiency standards. Accordingly, on a purely macro level, the supply of multifamily buildings with inefficient energy infrastructures is incredibly large. The availability of multifamily buildings alone presents a tremendous opportunity for companies specializing in energy efficient retrofitting to turn older, energy inefficient buildings into energy efficient/saving complexes [3]. A. Energy Consumption in Multi- Family Housing Multifamily buildings have operational elements that can translate into larger energy savings than a single-family home. From the energy necessary to light common areas, elevator and the HVAC units, the energy draw is significant. Energy use is even higher if all the leases in the complex include utilities or if access to common areas is provided 24 hours a day. Between the availability of paid utilities and tenant access to public spaces, energy is essentially being used all day- a stark contrast to a single home where the owner can control and customize all energy use on the property. However, if those common areas or the individual units were either built or retrofitted with energy saving devices, such as LED’s or EnergyStar rated equipment, the owner’s operating expenses go down and either his profits go up pp09thus maximizing his revenue [3].

From another part, an apartment building use significantly less energy than single-family house. This is due to that the apartment is so much tinier than single-family houses and therefore uses less energy. Alternatively, for being an urbanite it means lives efficiently, from taking public transportation and using bike shares to unplugging electronics and community composting. However, something else is also going on. Sure, the average home uses more energy than an apartment because of size. In addition, apartments generally have fewer windows and outside walls. By comparing the Multifamily housing with other type of residential building (Fig. 5), it can be concluded that the Urban Multifamily consume less energy than Green Suburban Single Family. The chart underscores a growing realization among environmentalists: It does not solve the problem to buy a hybrid and retrofit the house if all of that takes place 20 miles from the job. One would still consume more energy (“suburban single family green”) than an urban household without the latest green tech (“urban single family”). Moreover, that has as much to do with associated transportation emissions as the size and efficiency of the home [9].

Fig. 5 Household Energy Use in Compact (Urban Multi-family) versus Sprawling Neighbourhoods (Suburban Single Family Green) [9].

Table I reproduces a table that shows differences in energy consumption for single-family detached and attached (townhouse) homes, mobile homes, and multifamily housing, both two-unit to four-unit buildings and buildings with five or more units. It also shows energy consumption for each residential building type per square foot of living space, per household (or unit), and per household member (person living in the unit). As Table I reveals, single-family detached housing, which is common in American and European suburbs, has the highest energy consumption per square foot, while multifamily housing has the less [10]. TABLE I RESIDENTIAL ENERGY CONSUMPTION BY TYPE, 2005 [10]. Percent Per Per Per Square of Total Household Household (in Foot (in Consump Members (in millions of thousands Type tion millions of BTU) of BTU) BTU) Single 52.9 106.6 42.6 80.5% Family 39.8 108.3 39.7 73.9% Detached 47.3 91.7 37.0 6.6% Attached Multifami ly 2 to 4 units

67.6

63.7

29.5

14.8%

77.6

84.5

34.9

6.3%

5 or more units Mobile homes

61.7

53.8

26.4

8.5%

68.7

72.7

29.4

4.7%

B. Energy Efficiency Retrofitting in Multi-Family Housing Regardless of the sources, the energy efficiency of buildings is covered- the reduction of energy demands-is a central element of any sustainable strategy. At first glance, and considering these degrees of energy efficiency, a building that can supply its own energy seems to be just a step away. A selfsufficient building, i.e. a building that isn't connected to energy infrastructure, guarantees continuous energy supply based on the size of the building's own, typically solar energy system, and particularly of energy storage devices, without reverting to other, external resources [1]. Energy Efficiency (EE) measures in buildings are cost effective with the right approach. When EE is taken into consideration from the beginning of a building project, a construction budget can be released for EE equipment, or renewable energy systems, which further reduces the energy consumption. For other EE measures, the additional investments will be paid back within a few years – depending on electricity prices - as a result of lower energy bills [2]. Energy efficiency in new construction differs significantly from efficiency for existing buildings. New construction involves energy-efficient design from the start, with proper sizing of heating and air conditioning systems, proper insulation, vent and other sealing, and installation of efficient lighting and appliances. Energy efficiency in new buildings can be much more cost effective per square foot than retrofitting existing inefficient buildings [3]. As result, Energy efficiency in buildings concerns three main items:  The quality of building construction in terms of energy efficiency for both heating and cooling;  Sobriety in the use of energy-consuming equipment and equipment performance (using high efficiency equipment); and  The choice of the most suitable form of energy or technique for each use (for instance, solar water heater or cogeneration) [8]. In the residential sector, the potential of energy efficiency in electricity consumption concerns four uses: lighting, household appliances (primarily refrigerators and freezers), air conditioning, and stand-by modes (on household appliances and audio-visual equipment). There are two main ways to act on the energy consumption for these uses, for the same or better service: modify consumers’ behaviours, and improve the energy efficiency of the appliances used through regulatory measures and financial incentives: There is obviously a link between the outcome of behaviour modification and technical improvements. The latter can sometimes make up for deficiencies in the former, but it would be an illusion to think that energy efficiency is essentially a technical matter. Policy decisions on development and planning, as well as citizens’ attitudes about their consumption of goods and services are both decisive [8]. Energy efficiency retrofitting of buildings mainly address energy consumption for thermal comfort and, as a result, heating or cooling the inside of the building. It focuses

in priority on the quality of the building envelope (walls and openings), architectural design, and orientation (solar gain management). Usually, in accordance with thermal building code conventions, energy efficiency retrofitting addresses five uses:  heating  cooling,  ventilation Hot water supply  Lighting. Actually, energy consumption in a building also covers the energy used by appliances and equipment devoted to other uses, and in particular household or professional electric appliances. It will therefore be important – out of concern for energy efficiency, which must focus on total energy consumption in the building — to accompany thermal renovation programs with policies and measures addressing the energy efficiency of these appliances [8]. Technical interventions deal with insulating walls, upgrading openings, the heating system, air conditioning, the hot water supply system, ventilation and regulation. Concretely, they involve different types of actions:  Insulating roofs and outside walls: technical choices (exterior insulation, interior insulation, insulation included in structural materials);  Replacing doors and windows, installing blinds or shutters;  Upgrading or replacing the heating system (boiler, energy product used);  Upgrading or replacing the ventilation system;  Upgrading or replacing the air conditioning system (air conditioner, energy vector);  Upgrading or replacing the hot water supply system (e.g. installing solar water heaters); and  Installing or optimizing the heating, ventilation and air conditioning regulation system. [8]. These technical improvements must imperatively be accompanied by very strictly organized maintenance, without which the gains acquired thanks to the renovations risk deteriorating rapidly due to a lack of maintenance, supervision and adjustment of the equipment and systems installed. Particular attention should be paid to the behaviour of users occupying the building: setting a comfortable temperature (in winter and summer), monitoring lighting, putting equipment in stand-by mode or turning it off, etc. C. Deep Energy Retrofit of Castle Square Apartments The development is resident-owned and the building's denizens spearhead the deep energy retrofit project. They describe the retrofit project as "enclosure driven", meaning that it will focus primarily on the six sides of the building (four walls, roof, and foundation) to dramatically reduce Castle Square's heating and cooling demand. The retrofit will wrap the development's buildings in a new, airtight, superinsulated shell, a measure that will reduce heating needs by 61% and cooling by 68%. Residents will live in their units throughout retrofit construction [5]. Here is the suite of retrofits, arranged in what appears to be order of priority: 1. Super Insulate

The key difference between a Deep Energy Retrofit and standard energy efficiency renovations is insulation, which at Castle Square will be located on the outside of the building. A new super insulated shell (which visually transforms the dated property), combined with a super insulated reflective roof, high efficiency windows, will increase the insulation value of the building by a factor of ten. 2. Air Seal Without air sealing to stop leaks, insulation does not work very well. Air sealing is a simple as caulking cracks and holes to the outdoors and between apartments. Not air sealing is like only wearing a sweater (insulation) outdoors on a cold day. You are could until you put on a windbreaker (air sealing). Air sealing makes the super insulated shell work. It also limits the stack effect, reduces pests and improves indoor air. The super insulated shell and air sealing is expected minimizing cooling by 68% [5]. 3. Scale Down Heating and Cooling Equipment In typical leaky and poorly insulated buildings, big inefficient heating and cooling equipment generally compensates to make residents more comfortable. In contrast, a super insulated and air sealed building requires only a fraction of the energy to heat and cool [5]. The high efficiency heating equipment drops the building's heating needs by another 10%. Insulating the pipes and high efficiency boilers with indirect hot water heaters drop hot water energy usage by 41%. 4. Improve indoor air quality For deeper savings, heat recovery ventilation (HRV) precools incoming fresh air leaving the building (without cross contaminating it). At castle Square, we were not able to use HRV due to layout constraints and cost issues. Instead, we are using fresh air trickle vents and renovating the existing ventilation system with Aeroseal and CAR dampers [5]. Indoor air quality is anticipated to increase substantially at Castle Square. Heating and cooling needs are also expected to decrease by 3%. 5. Harness the sun 6. Reduce plug load The hoping result of the deep energy retrofit is 73% reduction in building energy consumption. This Boston project will quickly become a national model of deep energy retrofits at the multifamily building scale. III. RETROFITTING TRIPOLI MULTI-FAMILY APARTMENT BUILDING

The potential of retrofitting actions proposed for the local building should be assessed through energy calculation using high-accuracy computer models and climatic data. Analysis of the results exposes common trends in the energy performance of the building and permits extraction of information on the most suitable retrofitting interventions [15]. Therefore, before analysing any building in the city, one should describe the climate in which it is found; this allows one to anticipate many characteristics. Considered as the second largest city in

Lebanon- after Beirut- based on its area and number of inhabitants, Tripoli is the capital of North Lebanon province (Fig. 6), easily accessible by the northern coastal highway. It lies about 85 kilometres from Beirut, and rises to an altitude of 10 meters above sea level. It covers an area of 3994 hectares (39.94 sq. km - 15.42 mi ²) (Reference: www.Tripolilebanon.com).

Fig. 6 Tripoli Location

A. Tripoli Climate Tripoli that belongs to the north coastal plain of Lebanon has a warm and short winter and moderately hot and humid summers. The climate in the region of Tripoli is of the subtropical, Mediterranean type with warm and dry summer and fall (May to October), and moderately cold, windy, and wet winter (October to April). The average annual precipitation is 1,015 mm (Batroun station, altitude 20 m) while the average annual humidity is 70 percent. Temperatures are moderated throughout the year due to the warm Mediterranean Current coming from Western Europe. The average temperature in Tripoli is 28C in summer, 10C in winter, and the annual mean temperature is 20C. The maximum daily-recorded temperature has been 39.6C. Temperatures above 30'C occur for around 46 days per year. Days with temperature below 0C are very seldom with less than I day in average per year. The difference between day and night temperatures is usually 7 ᵒC (Fig. 7).[13]. Although snow is an extremely rare event that only occurs around once every 5 years, hail and sleet are very common and occur fairly regularly in the winter. Rainfall is concentrated in the winter months, with the summer typically being very dry) [5]. The sea and mountains located by the Abou Ali River determine the breeze and wind conditions. Prevailing winds are from the West and Southwest, while winds from the East and Northeast occur with less frequency (85 percent vs. 15 percent). [13].

Fig. 7 Average min. and max. Temperature in Tripoli, Lebanon

B. Amarra Residential Building Evaluation TABLE II AMMARA RESIDENTIAL BUILDING Architect

Dar-Sabsaby

Location Date Area

Tripoli, Lebanon 2009 4500 m2

Client Climatic zone Cost

Adnan Sabsaby Coastal 1,500,000 US $ (exclusive land price)

To transit from theoretical to a practical strategy, a typical residential building in the South-West of Tripoli city is chosen as case study building. The analysis of the building background, energy demand and used material, is essential to specify the energy efficiency level and the retrofitting strategies needed to upgrade the building performance and to reduce the energy consumption. Property condition assessment (PCA) is an evaluation of the current state of the building, providing an examination of existing conditions and serviceability and recommendations concerning repair and replacement [15]. Amara Residence is located in "Dam farez" zoning or "Consolidation and subdivision real estate " project in Tripoli which considered the new extension of the Tripoli city. In the past years, the Municipality completed the "Consolidation and subdivision real estate " project in " "Basatyn Trablous "zonning. This project includes about three million m2 of land in both regions which had been owned by thousands of citizens from Tripoli and its neighboring areas. This project came as a result for Tripoli's need for new areas for construction after the price of one square meter of land in some areas had exceeded four thousand dollars what led Tripoli citizens to the displacement from the city to the neighbouring district in search for a new residential area. This project contains lands and real estate with approximately same areas around 816 m2 with green areas and lighted roads and new network of infrastructure (www.3poli.net) (Fig. 8). Ammara residence is constructed in 816 m2 land covered 50% of the land. 1.

Background of Case Study The building was built with no standards taken into considerations in the field of energy efficiency. It was facing the main North Street and subject the local building regulation in field of natural ventilation and outlook to the range of vision. The building is a multifamily apartment type that consists of: - Basement Floor (Parking+ storage). -Ground Floor (Entrance+ Parking+ Door keeper room+2 Offices) -10 Typical Floors: each floor contains 2 symmetrical apartments (3 bedrooms) with total area each one 200 m2 (Fig. 9). -Top of Roof.

bathroom, (in the warm zone). That minimize the need for long hot water pipes, and reduce the amount of heat losses from the pipes and consequently the hot water use.

Fig. 8 "Consolidation and subdivision real estate " project in "Basatyn Trablous" zoning .(Municipality of Tripoli).

3. Case Study Building Envelope Design The structure used in this project is based on reinforced concrete structure with masonry block walls as internal wall partitions. The external walls consist of double masonry block walls with 2 cm air gravity. The cladding used in the building is white cut stone that covered only 17% of the building envelope. To achieve an Energy efficient building, the building envelope should be designed and constructed with low U-value (thermal transmittance) wall assemblies, roof assemblies, and floor and slab assemblies, glazing assemblies and door and other openings. Therefore, the building case study building design sheet was presented in the Table III. to be compared with the reference Thermal Transmittance values (Table IV) proposed by ALMEE and Order of Engineers and Architect in Lebanon through different Lebanese Climatic zone. By this comparison, with these two tables, we can be conclude that the U-values of the external wall, roof and glazing exceed the reference, what necessitate the used of external insulation in roof and external wall, and replacing the existing clear glass.

Fig. 9 Typical floor plan.

Fig. 11 Thermal zoning in the typical floor plan (researcher).

Fig. 10 Amara residential building case study from the North main street. (Researcher).

2. Orientation and Thermal Zoning of Case Study The project has a North South orientation with a deviation aligned with the land limit, 19ᵒ from a north-south axis. The North entry orientation of the building is suitable to prevent the solar heat gain. The occupancy patterns and thermal zoning determine was comparing to the building layout (Fig. 11). The typical floor is consisted of an East apartment and West apartment. Therefore, the location of the building functions differ between the two apartments in their relation with the solar radiation, certainly for rooms along the East and West side. The bedroom spaces are located in the South side that causes an unwanted heat gain. However, the reception area is located in the North side, which is considered the cool preferred area. The hot water-using services was grouped together, kitchen and

TABLE III DESIGN SHEET OF THE CASE STUDY BUILDING (RESEARCHER) u-value Details W/m2. K Stone (4cm)+ plaster(1.5 cm)+hollow External 1.33 block (10cm)+Air gap( 2cm)+ hollow wall block (10cm)+ plaster (1.5cm) Internal wall Floor

Roof Window

plaster(1.2 cm)+ hollow block (10cm)+ plaster (1.2cm)

2.5

Ceramic (1.5 cm)+screed (5 cm)+ concrete (6cm)+ hourdis block (32 cm) + Plaster (2cm) Concrete (6cm)+ hourdis block (32 cm) + Plaster (2cm) Single glazing

1.78

1.26 6

For any building with fenestration, one can evaluate the ratio of the total amount of solar radiation entering the building to the total solar radiation reaching the fenestration areas over an entire year. This ratio is used to determine the impact of the

TABLE IV REFERENCE THERMAL TRANSMITTANCE PER COMPONENT U-REF (W/M2K) VS. CLIMATIC ZONE Climatic Zone

Building Category

Uvalue Roof

1 Coastal

1Residential

0.71

2 Mid Mountain 3 Inland Plateau 4 High Mountain

U value window & skylight

presented in Table VI. Therefore, the existing building fenestration is compatible. TABLE V WWR OF THE AMMARA BUILDING ELEVATIONS (RESEARCHER)

U value Ground Floor Expose Semid Exposed

UValue wall 1.60

5.80

1.70

2.00

North

1.70

2.00

Elevation

Window area (m2) /Total wall area (m2)

2 N Residential

0.71

1.26

5.80

1Residential 2N Residential 1Residential 2N Residential 1Residential 2N Residential

0.63

0.77

4.00

0.77

1.20

3.30

0.70

1.20

4.00

0.77

1.20

3.30

0.70

1.20

Elevation South

3.30

0.66

1.00

Elevation

2.60

0.66

1.00

0.66

0.65

0.63

0.77

0.55

0.65

0.55

0.57

0.55

0.57

solar load on the heating and cooling energy usage of a building. This ratio depends on the following factors: ratio of windows to gross wall areas, glass solar heat gain coefficient and architectural shading factor. It is defined at the equivalent Window to Wall Ratio WWR-eq [7]. The maximum allowable Reference Widow to Wall Ratio WWR-ref presented in Table 5. was determined from a review of the current average fenestration ratio of existing buildings in Lebanon and the economics of using improved glazing and architectural shading devices to control the solar cooling load and to optimize the beneficial solar heat gain during the heating season. The equivalent Widow to Wall Ratio, WWR-eq for the proposed building is calculated using the following Equation: WWR-eq = Σ (Awi x SHGCwi x ASFwi) / Σ Av + 2 Σ (Asi x SHGCsi) / Σ Ah Awi = Area of the individual window (m2) SHGCwi = Solar Heat Gain Coefficient of the individual window ASFwi = Architectural shading factor of the individual window Av = Area of all vertical surfaces (opaque walls + windows) (m2) Asi = Area of the individual skylight (m2) SHGCsi = Solar Heat Gain Coefficient of the individual skylight Ah = Area of all horizontal surfaces (roofs + skylights) (m2)

Fig. 12 Single window glass characteristics [13].

As shown in the table V, the WWR-eq achieved in the different Ammara building Elevation is considered less than the respective tabulated maximum Window to wall ratio WWR-ref

West Elevation East

WWR

228x 0.82x0.7 / 700.5

0.18

98 x 0.82x0.95 /734

0.10

98 x 0.82x0.95 /734

0.10

108 x 0.82x1 /612

0.14

TABLE VI REFERENCE WINDOW TO WALL RATIO (WWR-REF) [7]. Building Maximum Reference Window Climatic Zone to Wall Ratio WWR ref Category 1 1Res. 0.22 Coastal Zone 2N Res. 0.21 2 Western mid Mountain 3 Inland Plateau 4 High Mountain

1 Res. 2 N Res. 1 Res. 2 N Res 1 Res. 2 N Res.

0.21 0.20 0.20 0.19 0.21 0.20

4. Case Study Energy Consumption (Energy Audit). Energy audit are investigations of energy use in a defined area or site. Energy audit is usually the first step towards identifying energy cost-saving measures for starting the retrofit process; also referred to as an energy analysis, an energy audit creates an energy use profile for the building and identifies energy inefficiencies within the building systems and envelope [16]. In general, the average annual household energy consumption has been found to be 6907 kWh, whereas per capita consumption is 1727 kWh. Referring to the annual bill of the apartment energy load in the Ammara building the seasonal and monthly variations are analyzed indicating increased energy consumption in the summer months accounting for 28% of total annual consumption (Fig. 13). The high energy using in the house is scored in August month due to the high need of cooling in this period.

1200 1000 800 600 400 200 0 January‐ February

March‐ April May ‐ june July‐ August September‐ November‐ October Decembre

Monthly Energy Consumption (KWh)

Fig. 13 Average monthly energy consumption of single Apartment in the Ammara building (bills) in kWh [Researcher].

In addition, referring to a professional calculation of the electricity used in the single apartment, the conditioning services scored the high percentage 25.39%, and the Lighting scored the second one 23.39%. However, the heating was not mentioned in this diagram, due to the gas energy source for heating (Fig. 14). Therefore, in the retrofitting strategies the upgrade should take in consideration the decreasing of the cooling and lighting load.

23.39 %

33.40 %

25.39 % Services power Conditionning

8.91%

8.91% Miscellaneous

Other (WH‐WS)

Lighting

TABLE VII EXISTING CASE OF THE CASE STUDY BUILDING AND POSSIBLE RETROFIT STRATEGIES THAT CAN BE APPLIED. Factor affecting Energy Efficiency Wall insulation

Building elements

Existing Performance

Possible retrofits strategies

Interior walls

Light-weight partirions

Adding insulation to interior walls

External walls

Uninsulated walls, external and internal 2 cm paint

Floor Insulation

Intermediate floors

Uninsulated

Roof Insulation

Roof

Uninsulated conventional roof

Fenestration

Windows

Single glass with aluminium frames

External doors WWR

Single glass with aluminium frames Compatible with WWR reference Conventional energy supply from EDL and private generator depending on non-renewable sources

Orientation Energy supply

Adding insulation layers to the building exterior Wall colours and shading Replacing slab with rigid insulation beneath Applying insulation to the underside of the floor Addition of insulation Cool roof coating Addition of green roof Addition of roof ponds Addition of building integrated photovoltaic Introducing new shading or light-shelves Using Interprane shading (roller blinds within glazing) Internal shading Building integrated photovoltaics for shading or glazing Replacing the window glazing Adding suspended film to existing window in the South, South-east, South-West Elevations Replacing the window frames Replacing the existing doors Adding solar panel system depending on solar power energy

C. Technical Tools and Interventions for Retrofitting Through the building's envelope audit, critical energy factors are identified, accordingly improvements that could be carried out are applied in the energy calculation for assessment. For daylight enhancement, single glazing could be replaced with clear double or triple glazing, and insulated window frames are used, external wall insulation can be applied as well to the building, spray-in place foam can help reduce infiltration through the building cracks. According to the Lebanese thermal standard, the WWR should be no more than 0.22 in the coastal Lebanese climatic zone, by comparing to the case study envelope , the most glazing North elevation scored 0.18 which is considered compatible. The south façade which is consisting of 14% fenestration, could be added with external shading to help reduce heat gains, in addition a vertical louvers could be added to the south-east and south west elevation .Green roofs can be added to the conventional roof already existing to improve the roof's u-value 0.71 W/m2K. Solar panel systems can be added to the existing building in the aim to transfer the energy supply system into clean renewable energy. As shown in Table VII a few strategies have been highlighted in the same category as they can give the same result depending on the resulting u-value which will be used in the energy calculation.

TABLE IX WWR OF THE AMMARA BUILDING ELEVATIONS AFTER REPLACING THE GLASS (RESEARCHER)

North Elevation West Elevation East Elevation South Elevation

Window area (m2) /Total wall area (m2) 228x 0.7x0.7 / 700.5

WWR 0.15

0.18

98 x 0.7x0.95 /734

0.08

0.10

98 x 0.7x0.95 /734

0.08

0.10

108 x 0.7x1 /612

0.12

0.14

all elevations except the North one , become less than 15%, that requires a specific U-values. Addition of 3cm of Polystyrene Extrude (XPS) Insulation to the external walls reduce its uvalue from 1.33 W/m2K to 0.50 W/m2K; according to the Lebanese thermal standard (Table X.) should not exceed 1.6 W/m2K. Insulating the roof reduced the U-value from 1.26 W/m2K to 0.39 W/m2k. Referring to a professional calculation, the Skin improvements reduced the cooling load of the building 25%, and reduce the heating load 61%. As result, can reduced the energy consumption 5%. TABLE X BUILDING ENVELOPE REQUIREMENTS FOR RESIDENTIAL BUILDINGS IN CLIMATE ZONE 1 (COASTAL) [7]

1.

External Insulation Referencing to the previous case study building evaluation, the building envelope need to improve its u-value. The Glazing was changed to double clear glass, which can be achieved in the Lebanese market. It reduce the windows and external doors uvalue from 6W/m2K to 3.3W/m2K and reduce the WWR in all building elevations as mentioned in the Table IX. The WWR in TABLE VIII DESIGN SHEET OF THE CASE STUDY BUILDING AFTER RETROFITTING (RESEARCHER) Details External wall

Internal wall Floor

Roof

Window

Stone (4cm)+ Polystyrene Extrude (XPS) Insulation (3 cm)+ plaster(1.5 cm)+hollow block (10cm)+Air gap( 2cm)+ hollow block (10cm)+ plaster (1.5cm) plaster(1.2 cm)+ hollow block (10cm)+ plaster (1.2cm) Ceramic (1.5 cm)+screed (5 cm)+ concrete (6cm)+ hourdis block (32 cm) + Plaster (2cm) Cement (4cm)+mortar(4 cm) +Insulation (5cm)+Screed(10cm)+C oncrete (6cm)+ hourdis block (32 cm) + Plaster (2cm) Double glazing

u-value(W/m2.K) 0.5

2.5

1.78

0.39

3.3

Window to Wall Ratio WWR (%) ≤ 15 %

0.71

U value Wall W/m2.K 1.60

16-25 %

0.71

1.60

5.8

26-35 %

0.71

1.60

4.0

36-45 %

0.71

1.26

3.3

U value Roof W/m2.K

U value Wind W/m2.K

SHGC

5.8

2. Solar Panel System To calculate the necessary number of photovoltaic panels needed and the quantity of electrical that should be generated by the panels in "watt", we should know the house's need of electricity. The first step in designing a solar PV system is to find out the total power and energy consumption of all loads needed by a Tripoli Typical house. The high energy using in the house is scored in August month due to the high need of cooling in this period (previously mentioned). Therefore, the electricity bill using as reference is belong to the July and August months where the total energy consumption scored 1200 Kwh.  Calculate total Watt-hours per day.There is a consumption about 1200 KWh during 2 months. Therefore, can be conclude that we have: 1,200,000 Watt through 60 days, so we have approximately 20,000 w/day. Multiply the total appliances Watt-hours per day times 1.3 (the energy lost in the system) to get the total Watt-hours per day which must be provided by the panels. 20,000 watt x 1.3 = 26,000 watt  We have to consider “panel generation factor” which differs at each site location. In Lebanon, the summer day is of a long day length and high brightness intensity, amounts to average 7 hours per day (http://www.upsaps.com). Calculate the total Watt-

peak rating required for PV modules. Divide the total Watthours per day needed from the PV modules by 7 to get the total Watt-peak rating needed. 26,000 watt / 7 = 3,714.28 wp  To calculate the number of PV panels for the system, we divide the answer obtained by the rated output Watt-peak of the PV modules (Fig.15) Increase any fractional part of result to the next highest full number to get the number of PV modules required. 3,714.28 / 225 = 16.5 modules

Fig. 15 Electrical specification of the Clearline PV module

Referring to the previous calculation, the number of PV panels needed to cover the electricity bill to one apartment is 17 panels. Therefore, the whole building need (17x20) 340 panels that cover (340x.1.5) 510 m2. However, the maximum roof area is 274 m2 able to fix 182 PV panel modules. Therefore, the proposed solar panel system can cover 50% of the electricity bill. In the other hand, the electricity bill does not represent the total energy need due to the blackout period that cover 75% of the energy need. As conclusion, the proposed PV system can generate 37% of the energy need.

Fig. 16 PV module dimensions cover 1.5 m2

IV. CONCLUSION The study identified several results using energy simulation and professional calculation of electricity consumption, heating and cooling load. As a result of the heating and cooling load,

the insulation of the external wall and roof and replacing the single glass with double glass, the heat gains and the cooling load becomes more efficient which reduces the total energy load of the building by 5%. In addition, the proposed Solar Panel system aimed to generate 37% of the needed energy. Therefore, we can reach a 42% reduction of the energy.

Fig. 17 Case study Plan masse with a proposed PV Panel distribution [Researcher].

Energy conservation through the use of energy efficient water heating systems(consume 8.9% of energy), lighting systems (23.3% of energy) and energy rated appliances (33.4 % of energy) leads to great reductions in energy consumption. Water management and reuse can also lead to reductions if integrated into building systems. Lighting systems as well can lead to great energy saving specially by proper integration of daylight and artificial light with automation systems which switch off when unoccupied or automatically dim when daylight is sufficient, which can cause reductions in light energy consumption by 35%. From an architectural view, the building envelope is considered the most important factor affecting the energy consumption of an existing building. The building envelope elements studied in this research ( WWR, thermal transfer, materials specification, orientation) can affect directly and indirectly other factors such as Heating and cooling systems, passive design, energy consumption, water management, lighting systems and renewable energy. These elements were studied in order to set the best retrofit strategies used in the building which can be suitable in the Tripoli city. Retrofitting is important to optimize the energy performance of existing buildings, and apply the most cost effective retrofit technologies to achieve enhanced energy performance while maintaining thermal comfort to the occupants. An energy audit should be done first to determine the energy inefficiencies within the building systems and especially for the envelope by

comparing the thermal specifications of the case study building with the Lebanese thermal standard in the coastal zone when Tripoli city is located. A typical apartment building (Ammara residential building) in Tripoli city-Lebanon was chosen for the case study and it was analysed and studied for the energy consumption reduction through the building envelope. The building envelope consists of walls, floors, fenestration and roofs; for walls and floors insulation can be applied as well as other alternatives fixation options. Retrofit of fenestration by adding shading devices( internal or external),also replacing the glazing reduces the glare and heat gains. As for roofs, insulation and renovation can take place, also adding a green roof to reduce heat island and reduces the thermal loads and adding building integrated photovoltaic can be another option for also generating electricity needed. ACKNOWLEDGMENT I would like to acknowledge all those who made the realization of this research possible. With a deep sense of gratitude, I would like to thank my main supervisors: Prof. Dr. Mohamad Fikry and Dr. Nabil Mohareb for their great help and their feedback. Their support, stimulating suggestion and encouragement were vital to my research. Profoundly, I am thankful for my mother and father for guiding and encouraging me along the way to achieve all my goals with success. I am also grateful for my siblings' support.

REFERENCES [1]

[2]

[3]

[4] [5] [6]

[7]

[8] [9] [10] [11]

[12]

[13]

Voss Karsten, Musall Eike. 2013. Net Zero Energy Buildings International Projects of Carbon Neutrality in Buildings. En0B, Energieoptimiertes Bauen. Med-Enec (Energy Efficiency in the construction Sector in the Meditearranean).November 2013.Energy Efficient Building Guideline for MENA Region. Energy Efficiency in Multi-Family Housing A Profile and Analysis,” by Matthew Brown and Mark Wolfe, Energy Programs Consortium, June 2007. Ministry of social affairs.2008.National study of household living conditions in 2007. http://hammerandhand.com/_blog/Field_Notes/post/Deep_energy_retrof it_strategy,_illustrated/ Oestrup Jan, Schuldt Charlotte,Seyppel Marcel.(2009).Nature is Future. Federal Ministry for the Environment, Nature Conservation and Nuclear Safety Comair Fady, Mortada Adel, Chehab Said,Matar Tony ,Sebrini Christophe.2011.Thermal Insulation Market in Lebanon.ALMEE, Order of Engineers and Architects- Beirut. AFD /September 2012 / Energy Efficiency Retrofitting of Buildings – Challenges and Methods http://www.theatlanticcities.com/housing/2011/12/missing-link-climatechange-single-family-suburban-homes/650/ http://www.heritage.org/research/reports/2010/10/the-lieberman-kerrycap-and-trade-bill-making-housing-less-affordable Matar Tony ,Mortada Adel, Zoghbi Nabil, Jaber Hassane, Chehab Said.2010.Solar Energy in Lebanon.ALMEE, Order of Engineers and Architects- Beirut. Mutasem El-Fadel. 2002. Draft Environmental impact assessment cultural heritage and Urban development project Lebanon . Council for development and reconstruction Beirut, Lebanon. http://signasystem.net/signa-system/retrofit-alternative/

[14] Mourtada A., Ordoqui J., Thibon J. L., Karaki, A., Cost-Effective Requirements Levels for Energy Performance of Buildings in Lebanon, EPIC 2006 AIVC, pp. 273-279, November 2006. [15] Tobias, L. (2009). Retrofitting Office buildings to be green and Energy Efficient. United States of America, Urban Land Institute. [16] Santamouris, M. and E. Dascalaki (2002). "Passive retrofitting of office buildings to improve their energy performance and indoor environment : The office project." Building and environment 37(6):575-578.