An Approach to the Zero Energy Building in Sana'a

*Samah Alramagha and Demet Irklı Eryıldız*

#### **Abstract**

Green building movement has grown in Sana'a/Yemen for the last decade for environmental and financial reasons is directly related to the energy consumption and the cost. Before the power outage, people used the electricity provided by the government from petrol. However, the power and water outages make people move towards sustainable energy and rational use of water. On the other hand, construction technology is still the same like using the materials without insulators and concrete bricks. The aim of this chapter is to learn what the construction of zero energy is, analyze the various examples of countries of hot dry climate convergence in Sana'a, design residential buildings in Sana'a, and test the building against consumption, cost, and performance requirements, thereby reducing non-renewable energy use in the construction sector. This study is very important to facilitate the development of zero energy building (ZEB) in developing regions that have hot dry climate in the world.

**Keywords:** zero energy building, energy efficiency, green building, rainwater harvesting, life-cycle cost

#### **1. Introduction**

 For nearly a quarter of a century, global temperatures and carbon dioxide emissions have increased particularly in Yemen [1]. In recent years, Yemen has been facing a major energy shortage that cannot provide the demands of the population and infrastructure. For nearly a decade, the power of electricity had fallen to less than 70%. However, in 2015, it became even worse because of internal and external conflicts. Yemen is rich in resources that could be enough to produce electricity to get enough energy for buildings [2]. The percentage of buildings using electricity is about 55% of the total energy in Yemen (**Figure 1**). If the building is operated by renewable energy, the problem of carbon emissions and energy shortage will be easily solved. That is why the zero energy building (ZEB) is very important in Yemen.

The residential buildings that are using renewable energy can significantly reduce emissions for the construction sector. Now, there are nearly 65% of buildings in Sana'a which use the basics of zero energy building (ZEB) such as using solar panels, trying to use less electricity and water. Zero energy buildings mean a reduced cost of living, higher resale values (as the demand for high-efficiency homes is increasing), and freedom from variable energy prices [3].

The chapter will explain recommendations for the best possible design solutions to reach ZEB in Sana'a. For residential buildings in dry and warm areas, the design and operation of passive and active systems quite different with cold and humid

#### *ISBS 2019 - 4th International Sustainable Buildings Symposium*

**Figure 1.**  *Electricity consumption profile [3].*

climate such as the ventilation, heating, and cooling systems, while other energy results could be similar, such as lighting, harvesting water, solar panels, and household appliances. Energy consumption will be reduced to make it cleaner and less expensive to meet the building's energy needs that will be provided by renewable energy sources. Building energy consumption will be determined by several different means, including integrated design, low load components, energy conservation programs, and energy efficiency updates.

#### **1.1 Background**

 Historically, Yemen has established a unique, rich, distinctive, and unified style of sustainable traditional Yemeni architecture. However, a few years ago, this traditional style was successfully preserved in construction. Traditional buildings in Yemen were characterized by use of local materials and implementation of traditional methods and techniques. Some of the traditional buildings contain up to eight levels and have carrier walls built either with carved stone or mud, depending on materials available in the area.

The constant evolution in infrastructure and housing projects has caused transformation of traditional buildings into modern and modern/traditional buildings. Traditional Yemeni buildings are developed well with difficulties in different climatic zones of Yemen and effective use of local resources. On the other hand, modern and modern buildings were designed inappropriately due to the use of unsustainable materials and various techniques to reduce cost, thus creating a less attractive and unsustainable environment [4].

#### **1.2 Methodology**

This research method started with literature review to collection data from various books, research articles, and scientific journals related to the model in order to study for a better understanding of the concept of zero energy construction. Then analyzing four existing buildings in different country which have dry and hot climate. Then, using Autodesk Revit © 2014/2019 program and websites, analyze the data and obtain the desired results.

#### **1.3 Hot and dry climate**

Climate in Yemen is often hot and dry and the central highlands have an annual temperature of 21°C. The average daily temperature in January is 13.9°C *An Approach to the Zero Energy Building in Sana'a DOI: http://dx.doi.org/10.5772/intechopen.87836*

**Figure 2.**  *Yemen map temperature [5].*

 and in July 21.5°C (**Figure 2**) [5]. In Sana'a, the sunshines all year round, but the hours of sunshine diminish a bit in July and August. In Sana'a, the temperature is warm in the summer. The daily average is about (75°F) 24°C. The winter is pleasantly warm and sunny during the day, with highs around 21/23°C from November to February, but the temperature at night drops to around 10°C and sometimes below.

 The average annual rainfall in Sana'a ranges between 200 and 500 mm. The rainfall in Sana'a is characterized by two seasons, one of which starts from April to May, while the other one starts from July until the first half of August. Clouds generally gather on the western slopes, causing very heavy rain lead to the erosion of valleys and soil [6]. A series of dams and small canals help to collect rain water.

#### **2. Analysis of existing building**

In this section, four examples were analyzed to understand how the zero energy building works.

#### **2.1 AREE Aqaba Residence**

The design of the building is adapted to the local climate and takes advantage of design elements to provide maximum energy through the building orientation, materials, ventilation, and window shading. Moreover, having a garden in the roof will definitely help to absorb the temperature in a more effective way.

The cost is greatly considered according to this design. For example, the design of the bathrooms should be all on the same side on each floor, which makes it cheaper compared to other designs. In addition to the design, the materials used are local and this makes it very cheap. Finally, this house is provided by a solar heater to use less energy, which leads to less expenses (**Table 1**) [7].

#### **2.2 Josh's House**

The project is characterized using local building materials and easy construction. The project shows how to use the garden in a way that allows the building to connect with nature and create space for the children's playground, as well as providing a garden for the production of local vegetables. For now, the house is being used to collect performance data and test new technology. The building designs have achieved a 10 Star Nationwide House Energy Rating Scheme (NatHERS) (**Table 2**) [8].

#### **2.3 Vali Homes Prototype**

This house is characterized using a comprehensive insulation method to reduce energy. In addition, measures have been taken to reduce unwanted heat transfer. Also, the materials used in the building with suitable characteristics that are easy to install and maintain make the costs less. Tightly sealed building envelope including vapor barrier beneath the slab, sealing all floor penetrations, house-wrap tape sealant, and gaskets at all openings. Utilized wood doors with aluminum cladding help reduce thermal heat gain (**Table 3**) [9].

#### **2.4 Bayt Al-dahab**

 The house is located in the capital Sana'a, where it was built in 2002 with the modern Yemeni character. The building was converted to renewable energy in 2010, providing the building with solar panel and solar heaters to completely accommodate the building throughout the day. On rainy and cloudy days, solar energy stops working, and the generators are used instead. The house is for a family consisting of a father, a mother, and three children. The house consists of five rooms, three bathrooms, a living room, a kitchen and a basement floor. The house was built with local stones, from the bottom of a black (basalt) stones to protect it from water. Also, first and the second floors used beige (Saadi) stones. To provide water, the house was equipped with a ground tank to conserve water from the government sporadically (not from the rain) and then using filters that filter the water. The house is equipped with Yemeni colored curved windows (Qamariah) that are characterized by Yemeni character (**Table 4**).

Four zero energy buildings are compared in terms of location, material, wind, solar energy, water use, and biomass use. The comparison is presented in **Table 5**.

**Table 1.**  *General information about AREE Aqaba Residence.*

### **Table 2.**

*General information about Josh's House.*

#### **Table 3.**

*General information Vali Home Prototype.*

#### **Table 4.**

*General information Bayt Al-Dahab.*

*ISBS 2019 - 4th International Sustainable Buildings Symposium*

#### **Table 5.**

*Comparison between existing buildings.*

#### **3. Design of the zero energy house in Sana'a**

Zero Energy House in Sana'a was designed by Autodesk Revit 2014 and 2019, program for Energy analyzing to get the best results. This analysis will be explained as followed:

#### **3.1 Orientation**

As shown in **Figure 3** by using Revit simulation, the long sides of the buildings were oriented east and west. The southern facade is the best concerning sun exposure throughout the day, especially in the winter. On the 21st December, the sun will rise 84° east of due south and set 84° west of due south. On the 21st March/21st September, the sun will rise 91° east of due south and set 91° west of due south. On the 21st June, the sun will rise 98° east of due south and set 98° west of due south [10]. *An Approach to the Zero Energy Building in Sana'a DOI: http://dx.doi.org/10.5772/intechopen.87836*

**Figure 3.**  *Summer and winter path of the sun (Autodesk-Revit).*

#### **3.2 Layout**

The floors are carefully planned, the ground floor has the dining rooms, the guest room, living room, the garage, two bathrooms, and the kitchen. First and second floors have the bedrooms, which are most likely to gain temperature during the winter. Bedrooms are located on the south side to keep the heat warm during the winter. Garage was placed on the north side to protect the living room from the cold monsoons during the winter. Bathrooms and kitchen were placed on the east side with the same side to reduce the cost.

#### **3.3 Walls and wall materials**

 To select the appropriate building material in, a simulation study was carried out on a computer model of a concrete block building existing in Sana'a, to ascertain the direct effect of the materials on their thermal behavior. During the research, the building material was changed for each type of wall. Throughout the research, the red, brick, stone, and concrete bricks were tested. Natural materials have been shown to have fantastic thermal properties than modern materials. The stone is considered the most expensive material available in the market. It has also been noted that thermal evaporator was better, but stone section in **Figure 4** is characterized by the best thermal comfort during the summer and winter. While the stone is characterized by thermal comfort during the summer. If the summer temperature is higher than normal due to global warming, the problem can be solved through ventilation provided to the house [11].

#### **3.4 Insulation**

 Rock wool, polystyrene, and sand straw mixture was chosen for heating insulation inside the walls, which is considered an excellent insulation. It must be carefully formulated because if exposed to water and its vapor, the insulation effect ends. This is not a major concern in the dry hot climate. Covering thermal beams with insulation in the intersection of walls is very important because thermal beams represent energy losses of 20% if they are not covered with insulation (**Figure 8**).

#### **3.5 Roof**

In Yemen, the sun's rays are almost vertical on the surface of the earth during the summer, with the sun's angle approximately 98°. Because of the sun's stability on the surface of the house, the surface is more likely to absorb heat from the sun. Therefore, it is important to cover the roof with thermal insulation, where the roof of the house was covered with a layer of buffer 5 cm, and a layer of stable sand mixed with a little cement added instead of using a layer filled with cement as

#### *ISBS 2019 - 4th International Sustainable Buildings Symposium*

#### **Figure 4.**

*Section of the building's wall construction.*

shown in **Figure 5**. The sand is considered having a lower thermal conductivity. It also has a high thermal mass, which helps improve surface insulation.

#### **3.6 Windows**

The windows of the house have been designed large and long in the eastern, western, and southern facades in order to allow daylight to enter the house. The glass dome located in the center of the building where it acts as a heat collector during the winter. The double windows have been installed throughout the house. The double glass reduces the value of U from 5.9 to 2.9 W/km2 .

#### **3.7 Domestic hot water supply**

Water during the summer in Sana'a hardly needs heating continuously, but in the winter, the solar heater must be provided by a system of solar panels that heat the water. The system used 11 panels, and each panel has 24 channels. It is necessary to leave a space between the panels for maintenance. The plates are placed on a roof to the south side at a 15° angle in order to make maximum use of sunlight throughout the year.

#### **3.8 Heating system**

 The diagram in **Figure 6** shows the house is a loss of heat during the winter through walls and roof maximum in January. As the winter in Sana'a is sunny, the temperature rises during the day to sometimes reach 18°C, which helps the house to store the amount of heat inside the house during the night.

*An Approach to the Zero Energy Building in Sana'a DOI: http://dx.doi.org/10.5772/intechopen.87836*

**Figure 5.**  *Section of the building's roof construction.*

**Figure 6.**  *Monthly heating load (Autodesk Revit ©—Energy analysis).*

In the winter, if the climate is cooler due to climate change, portable natural gas heaters will be available inside the house. The figure also shows that the heating does not rise inside the house during the summer. These help to maintain the amount of energy used inside the home.

#### **3.9 Cooling system**

As can be seen in **Figure 7**, the cooling system is reduced in the winter from November to April. However, in the summer from July to September, the plan shows that the building is cooling due to the ventilation system that has been studied at home which provides a natural ventilation system inside the house.

 The windows were placed on each floor so that they are opposite to each other as shown in **Figure 7**. Each floor shows how the window's location designed and the

#### **Figure 7.**

*Monthly cooling load (Autodesk Revit ©—Energy analysis).*

air movement inside the room in order to give the maximum amount of ventilation. Even if the doors are closed, interior doors are designed on small openings above maintaining ventilation.

The stairs are also designed to function as a tower to move the cold air to each floor in **Figure 8**. In addition, there are openings between each floor and another for transferring hot air in the summer from the bottom to the top.

#### **3.10 Thermal system**

 The temperature of the house was reduced from 20 to 18°C in the summer, while in the winter the temperature was kept between 14 and 18°C. The bedroom is considered the warmest during the winter. In January, there is a cold week according to measurements during which the building was closed. However, the internal temperatures are close to comfort, and since the building is inhabited, it is likely to raise this level by 2°, especially if ventilation is used during the day because the temperature is somewhat high and may reach 18° during the winter. Thus, the building performs very well in the winter.

#### **3.11 Natural lighting**

 Natural lighting is one of the most important aspects of building design in many ways. In order to provide the largest amount of natural lighting, the window openings were designed to allow natural light to enter and distribute throughout the house. The glass dome is designed above the living room so that it allows as much light as possible to get inside. It is a northern windshield so that the direct sunlight does not reach it in the summer and causes the house to warm up.

**Figure 8.**  *Ventilation system in ground, first, second floor and section (Autodesk Revit ©).*

*An Approach to the Zero Energy Building in Sana'a DOI: http://dx.doi.org/10.5772/intechopen.87836*

In the case study project, it turns out that we have good natural lighting of the eastern, western, and southern facades and avoid windows on the western and eastern facades in order to obtain maximum control of direct solar radiation, glare, and more homogeneous lighting distribution in **Figure 9**.

**Figure 9.**  *Natural light inside the house (Autodesk Revit ©).*

#### **3.12 Photovoltaic (PV) cells**

Photovoltaic cells generate electricity for the entire house. The photovoltaic cells in the house can generate more electrical energy than the house needs. Through a collection of calculations conducted in the research, the project has been equipped with 16 photovoltaic cells on the roof of the house in the south to provide the best efficiency of photovoltaic cells, each of which generates 370 W. The corresponding **Figure 10** shows the angle of the solar panels each month of the year to achieve the greatest possible efficiency.

#### **3.13 Gray-water recycling and reuse**

 In order to reduce the cost of the house, it was equipped with a gray water system for the use and absorption of gray water as shown in **Figure 11**. The system

**Figure 10.**

*Sana'a optimum tilt of solar panel by month [10].*

**Figure 11.**  *Gray-water recycling system [12].*

works in a way to collect gray-water from bath basins and kitchen first in a small tank containing filtration of solid objects that may exist. Then, the gray-water passes through the wet flowers of three layers planted from bamboo, which helps to filter water more. Then the filtered water passes into a coal filter that eliminates the foul odors caused by the gray-water. Then the water reaches another tank to store and to irrigate agricultural crops inside the house [12].

#### **3.14 Rainwater harvesting**

The annual rainfall is generally between 150 and 350 mm, where there are two rainy seasons, separated by a distinct dry season (May–mid July). The amount of rainfall varies from one year to another, with precipitation amounts greater than 350 mm. About 65–75% of rainfalls during the months January–June. There is a difference in the amount of rainfall, which is 5 mm/day between 5 and 15 days. The average amount of rainfall on a rainy day is about 16–17 mm. The evaporation rate varies depending on height, wind exposure, and latitude. Ranging from 3 to 3.5 mm/day during the dry and cold periods and 5–6 mm/day during May–June. The average total evaporation per year is about 1700 mm.

 The process was carried out to calculate the capacity of the storage tank taking into account the amount of accumulated water in and out. This value appears to be 16.08 m3 in March. According to this value, the size of the tank can be designed with the addition of 25% of the water volume to accommodate any rise in rainfall amount may occur. We can form a graph of accumulated water and cumulative demand and calculate the maximum storage requirements (**Figure 12**) that occurs in March. All this water must be stored to cover shortages during the dry period [13].

#### **3.15 Life-cycle cost**

Saving cost is one of the most important characteristics of ZEB. To reduce cost in the Sana'a project, the house was designed with local materials, the bathrooms and the kitchen were designed on the same side of the house, provided natural ventilation inside the house, the temperature was regulated during the winter, and the increased thermal insulation may save operating costs and reduce investment levels in refrigeration devices and provided the house with appliances that consumed fewer watts. Also, the photovoltaic cells calculated for home operation is shown in **Figure 13**. The cost of solar panels has been calculated in Yemen, where solar panels will save around \$1020 per year. The repayment period of solar panels and batteries is about 12.7 years. As shown in **Figure 13**, the battery will change and that cost around \$9000 every 10 years [14].

#### **Figure 12.**

*Showing the predicted cumulative inflow and outflow from the tank [13].*

**Figure 13.**  *Compering solar panels and without solar panels [14].*

#### **4. Conclusions**

This chapter reviewed the state of buildings in Sana'a and the energy problems it experienced. Then, some examples of ZEB houses were presented. The design of a building in Sana'a uses zero energy standards and other performance factors as a basis for analysis. The development and capability ZEB design has been presented in Sana'a by including heating, cooling, hot water, roof, windows, and wall materials analysis.

The floors are carefully designed so that the rooms are in the warm side and careful to enter the sunshine into the living room. Stone has been chosen as a major building material because stones are the best thermal comfort during the summer. Wall insulation materials such as rock wool and polystyrene have been added for good thermal insulation during the hot summer and sandblast for thermal insulation inside the walls. The addition of glazed double glass reduces the value of U from 5.9 to 2.9 W/km2 . Hot water plates are placed on a tilted to the south side at a 15° angle in order to make maximum use of sunlight throughout the year. The house works on the loss of temperature during the winter from the walls and the maximum ceiling in January is larger. Winter is sunny in Sana'a. Where the temperature rises during the day to a degree Celsius, helps the house to keep up the temperature at night. The cooling system is the least possible in the winter because the house

does not need to be colder. In the summer, a ventilation system was studied inside the house to work on cooling it from the inside. For natural lighting, window openings are designed to allow natural light to enter and distribute throughout the house. The house is equipped with reservoirs collecting annual rainwater, with a total annual evaporation of about 1700 mm.

A zero energy building has been reached at the lowest cost through the use of local building materials, reduced energy use, and the collection of rainwater and gray-water. This project has been designed to be an initial approach to what ZEB buildings should be in Sana'a.

#### **Author details**

Samah Alramagha\* and Demet Irklı Eryıldız Department of Architecture, İstanbul Okan University, İstanbul, Turkey

\*Address all correspondence to<EMAIL_ADDRESS>
© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

*An Approach to the Zero Energy Building in Sana'a DOI: http://dx.doi.org/10.5772/intechopen.87836*

#### **References**

 [1] Fakh'ri I, Hassen T, Wassim T. Effects of CO2 Emissions on Economic Growth. Urbanization and Welfare: MPRA Paper No. 65683. 2015;**11**:53 UTC

[2] Qasem AQS. Applications of renewable energy in Yemen. Journal of Fundamentals of Renewable Energy and Applications. 2018;**8**(254):1. DOI: 10.4172/2090-4541.1000254

[3] Hoque S, Iqbal N. Building to net zero in the developing world. Buildings. 2015;**5**:57. DOI: 10.3390/ buildings5010056

[4] Sultan B. Modern/traditional buildings in Yemen and sustainability. In: The First Engineering Conference of Yemeni Architecture; 29-30 January 2008; Aden University

[5] Yemen Map Temperature. Petaluma, CA: World Trade Press; 2007. Available from: http://www.stockmapagency. com/Temperature\_Map\_Yemen\_C-Yeme-2007-Temp.php [Accessed: 2018-08-10]

 [6] Hadden RL. The Geology of Yemen: An Annotated Bibliography of Yemen's Geology, Geography and Earth Science. Alexandria, VA: US Army Corps of Engineers Army Geospatial Center; 2012. pp. 8-10

 [7] Rosenlund H, Emtairah T, Visser F. Building green in Jordan? Performance evaluation of the Aqaba Residential Energy Efficiency Pilot Project (AREE). In: The 2nd International Conference on Sustainable Architecture and Urban Development. 2010

[8] Josh's House. Josh Byrne & Associates [Internet]. 2018. Available from: https:// joshshouse.com.au/about-the-project/ [Accessed: 2018-06-28]

[9] International Living Future Institute [Internet]. 2018. Available from: https:// living-future.org/lbc/case-studies/valihomes-prototype/#energy [Accessed: 2018-08-15]

[10] Solar Electricity Handbook 2019 Edition [Internet]. 2018. Available from: http://solarelectricityhandbook.com/ solar-angle-calculator.html [Accessed: 2018-10-12]

[11] Alhaddad MA, Jun ZT. A comparative study of the thermal comfort of different building materials in Sana'a. Architecture and urban faculty. American Journal of Engineering and Applied Sciences. 2013;**6**(1):20-24

[12] Khasawneh J. AREE—Aqaba Residence Energy Efficiency. The Center for the Study of the Built Environment (CSBE); 2011. 44 p

[13] Salleh SA, Taher TM. Rooftop Rainwater Harvesting in Modern Cities: A Case Study For Sana'a City, Yemen. Journal of Science & Technology. 2012;**2**(17):51, 52, 61-63

[14] The Solar Electricity Handbook. 2019 [Internet]. 2018. Available from: http://solarelectricityhandbook.com/ solar-angle-calculator.html [Accessed: 2018-12-09]

**113**

**Chapter 9**

**Abstract**

settlement certificate.

office building

**1. Introduction**

Office Building

Certification for Sustainability:

Construction Process of Via Green

In the twentieth century, developments in technology and industry not only increased energy consumption, but also initiated a period of oil crisis and environmental pollution. "Construction sector" is one of the leading actors of environmental problems which consumes 40% of the primary energy over the world and naturally takes on the responsibility of energy efficiency problem. Therefore, many researches and implementations have been initiated and shared in many platforms at individual, organizational, and inter-state level. Leadership Energy and Environmental Design (LEED) Certificate is one of these studies. In this research, it is examined that "Via Green Office Building" with LEED Gold Certificate according to LEED 2009 Core&Shell Version-3. Our goal is to reveal the differences of design and construction process of LEED certificated buildings by comparing with the conventional buildings which have been only built according to legal compulsions in Turkey. With this scope, the office building have been examined according to LEED's Key Performance Indicators (KPIs) through project and LEED documents. Finally, it is suggested that in order to develop sustainable/green buildings in Turkey, it is necessary to add new articles into the national legislations and regulations and make it compulsory for buildings to have

**Keywords:** energy, sustainability, certification, LEED, project management,

required to build sustainable buildings even more within this century.

Each project in construction sector has unique attributes. Location, design, environment, situation, and people involved can be called as "key characteristics" which determines the project direction [1]. In addition, all projects have a significant scope. Project works have been mainly shaped to provide healthy environments and energy efficiency in built environments due to concerns of global warming and its threat for earth. Therefore, sustainable development concept was first launched in the 1970s and many other studies that are relevant to environment and energy issues had increased dramatically in following years. Sensitive approaches are

An Assessment on Design and

*Fatma Handan Sarıgül and Semra Arslan Selçuk*

#### **Chapter 9**