CD Reduces Energy Consumption

Climatic Design of Buildings
Can Reduce Consumption of Non-Renewable Fossil Fuels

MORTEZA KASMAEI
September 2008

Abstract
Although the use of climatic design (CD) systems in achieving comfort conditions in buildings in different climate types has been addressed for over three decades, the importance of CD can be only gauged today in the context of climate change and the contribution of buildings in the emission of greenhouse gases. This study of climatic data from 216 meteorological stations was completed in the year 1990, with the primary objective of classifying Iran’s climatic zones and preparing guidelines for adapting residential buildings to local climate, thereby reducing the period of mechanical heating/cooling/ventilation during the year.  The significant findings of the study have a direct bearing on the consumption of non-renewable fossil fuel in buildings, and therefore on the emission of greenhouse gases contributing to consequent climate change.

 

Climatic Design Traditions in Iran
It is indeed a paradox that contemporary Iran is among the world’s highest per capita consumer of energy in buildings, whereas its architectural and urban heritage is living proof of the fact that ancient Iran was one of the world’s leading nations in the development and use of ingenious systems that made use of available natural resources to create comfortable living conditions in its buildings and cities, often in very hostile climates, in a sustainable manner. Examples of traditional buildings and cities, demonstrating these systems exist in almost every part of Iran’s varied geography and its accompanying wide-ranging climatic zones.  This has been achieved through a highly sensitized, almost intuitive understanding of natural forces and respect bordering on veneration, for the natural environment and its complex ecosystem, to maximize the utilization of natural resources in the design of buildings and urban systems, without interfering with the natural environment system. In, what may be termed as ‘Climatic Design’ (CD), the use of fossil fuel for heating and cooling has been minimized significantly in traditional buildings and urban areas to a very small period of the year.

Climatic Design in Buildings in the Context of Climate Change
This paper reports the findings of a study conducted in the year 1990, using meteorological data from 216 meteorological stations in Iran to show that Climatic Design (CD) which includes appropriate building orientation, size and location for windows, adequate thermal properties of exterior walls, openings, roof and floor (in short the building envelope) for different climate zones, can reduce energy consumption in buildings, achieving energy savings of up to 70% annually. Implemented in one of the harshest climates of Iran, CD reduced the duration of annual heating and cooling needs of a residential building from 77% of the year (6504 Hours) to only 13% of the year (1128 Hours).

This study was unique for its time and its importance has only increased since, as well as its relevance to one of the most outstanding issues today –combating climate change; in view of the recent understanding of factors contributing to climate change and the urgency needed to combat this phenomenon as well as to adapt to it. The United Nations has officially acknowledged that climate change is a serious and long-term challenge with potentially irreversible consequences. This statement was first acknowledged globally – (almost globally, since America backed out as a signatory) in the Kyoto Treaty in December 1997, for combating climate change by reducing the emission of greenhouse gases. The world has come a long way since and in the years, 2007/2008 Climate change and its related issues are among the topmost priorities of the UNDP, as dealt in the Human Development Report 2007/2008, MDG 2007 report as well as in the World Development Indicators (WDI)-2007 by the World Bank. The WDI 2008 report of the World Bank states that buildings contribute to 15.3% of the total Greenhouse Gas Emissions, more than transport, which has a share of 13.8%. The report also quotes the finding of the Intergovernmental Panel on Climate Change (IPCC) in 2007, that carbon dioxide, which constitutes the bulk of greenhouse gases, with 77% concentration of the total emissions, has increased one-third faster in the last decade than in the last fifty years. ‘Climate change poses risks for the environment and for development in most economies, disproportionately affecting those with the lowest capacity to adapt to such impacts. That makes climate change a development issue critical to poverty reduction (and access to information and awareness and a knowledge based approach to sustainable development). It is also an environmental issue vital to sustaining growth and preserving the eco-system. Countries need measures to mitigate it – and to adapt to its unavoidable outcomes.

The growing awareness of the role of buildings in climate change is paralleled by increasing attention being paid to energy saving in buildings. A new European directive provides for the application of minimum standards to energy saving in buildings. In the USA, a survey report, of responses by Mayors of 134 cities in April and May 2007, shows that nine in ten cities in the USA, require or intend to require in the coming year that new public buildings be energy efficient, healthy and environmentally sustainable and that more than three in four cities are encouraging the private sector to build buildings that are energy efficient, healthy and use sustainable building techniques. Two-thirds of the cities has an individual in the government who is responsible on a full time or part time basis for the city’s climate  protection activities; more than nine in ten of the cities consider efforts to reduce greenhouse gas emissions as part of their broader efforts to address public health concerns such as improving air quality or encouraging active living; and in nearly three of four cities, the Mayor has reached out to other mayors, elected county officials and other leaders to sign on to the Climate Protection Agreement or take action on climate protection. The report states that ‘By far buildings account for the highest proportion of energy consumption and greenhouse gas emissions; and consequently they represent the greatest opportunity for obtainable energy efficiency improvements. To meet this opportunity, specifically, 60% of American cities currently have a policy for energy efficient, healthy and environmentally efficient buildings, and another 28% will adopt a policy in the next year. Nearly three of four of the cities have changed or are in the process of changing their residential and commercial building codes and/or ordinances to encourage construction of new buildings that are energy efficient, healthy, and environmentally sustainable. Eighty seven percent of the cities require that public buildings undergoing major rehabilitation be energy efficient, healthy, and environmentally sustainable.

A study report published by BRANZ in 2007, on the  ‘Assessment of the need to adapt buildings in the New Zealand to the impacts of Climate Change’ reports that residential buildings provide the greatest opportunity for adaptation for climate change, followed by non residential (institutional and commercial) buildings and then by civil engineering structures. The study identifies that Thermal Comfort is directly related to energy consumption that not only affects climate change, but is also bound to increase energy consumption when climate changes occur. The main building components that can contribute to thermal comfort in buildings, while contributing to energy efficiency are

• Window shading
• Insulation of roof, floors and walls,
• Provision for natural ventilation; and/or
• Double Glazing or further advanced performance

Iran’s Commitment in Combating Climate Change
As a signatory to the United Nations Framework Convention on Climate Change[UNFCCC], Iran is committed to reduce its anthropogenic greenhouse gas emissions by source and removal by sinks (those gases not controlled by the Montreal protocol) to the Conference of Parties on a periodical basis on the basis of methodologies given by the IPCC designated by the Conference of Parties, as well as regularly update their programs and measures for the reduction of GHG emissions and implement them. Iran’s National Climate Change Office, established in 1988 in the Environmental Research Center of the Department of Environment, with assistance from GEF and the UNDP.

In a CDM Game Plan for Iran,  one of the main opportunities has been identified in the area of energy efficiency in commercial and residential buildings, through building design, lighting, heating and cooling and use of energy efficient appliance. The building types cover hospitals, hotels, banks, office buildings, government offices, restaurants, markets and shops and schools, individual houses and apartment blocks. Of the three main sectors responsible for energy consumption and related GHG emissions- Industry, Transport, and Buildings- buildings account for 45% of energy use, more than by industry or transport. It is also a field for achieving large energy savings, often at little cost.  CDM projects require quantifiable monitoring with effective results, which is much better achieved in the buildings sector rather than in the transport sector.

During the last decade, CO2 emissions from the residential and tertiary sector have been raising continuously and therefore an area of concern to be targeted for emission reduction measures in the national policy. Economic growth has also been linked to increase in energy consumption, and to meet the challenge energy efficiency in the buildings and transport sector has been identified as a priority over other economic sectors.

In short, the role of energy efficiency in buildings has taken on a critical position in combating climate change. ]

Background to Climatic Design in Iran in Achieving Thermal Comfort in Buildings
In the last quarter of the 20^th Century, there was a worldwide surge in research and studies recommending that design of buildings and man made environment pay due consideration and respect to local climate and geography. The argument in favor of climatic design was the logic of place, function, and identity. The publication of books such as ‘Climate and comfort in buildings’[xiii] and ‘Architecture in hot and dry climate’[xiv] had tremendous impact nationally in reviewing traditional and vernacular architecture and their effective use of passive energy sources in creating comfort conditions in buildings. The further publication of the books ‘Climate and Architecture’[xv] and ‘Design with Climate’[xvi] in the years 1984 & 1989, covered a wide range of climatic conditions of Iran for adaptation of buildings to local climates, using natural passive and renewable energy resources, minimizing dependence on fossil fuels for heating and cooling. These publications are of special relevance to Iran, since they cite several examples from traditional Iranian architecture as model systems in the adaptation of buildings to local climate. In turn, modern architecture in Iran, during the same period shows a reciprocal response to the findings of the studies published, by extensive adaptation of traditional building design systems, especially for heating and cooling, to contemporary buildings with new uses.

The importance given to Climatic Design in Iran was still in evidence in 1990, when the rebuilding of cities in Khuzestan Province was being planned towards the end of the Iran-Iraq war. Several key cities in this province saw severe damage during the war, and the Ministry of Housing and Urban Development defined a project for the study of ‘Climate and Architecture in Khuzestan – Khorramshahr’[xvii] in the ‘Building and Housing Research Center (BHRC)’ operating under the auspices of the Ministry, as a priority project in preparation of eventual design for reconstruction and rebuilding. The findings of the research project were published in 1990, with the same project title.

The research project was a forerunner to an eventually wider study covering the entire country, covering all of the 216 meteorological stations, called ‘Climatic Zoning of Iran–Housing and the Residential Environment. The goal of the research project was to prepare the tools for CD for architects and planners, for Iran’s different climatic zones. The findings of the study provided compelling evidence of the need for use of CD tools in buildings, especially in the residential environment, both for saving consumption of fossil fuels and expensive installation of heating and cooling systems; as well as for its contribution to improving the quality of the built environment and its fall out in contributing to the quality of residential and urban living. The findings of the study were summarized in the form of a climatic zoning map of Iran, with 8 zones and 36 sub-zones, recommending design tools for use in buildings in the various zones. The High Council of Architecture and Urban Planning approved the climatic zoning map as the authorized source for use in the design and planning of buildings, as well as residential neighborhoods in the country. All City Master Plans, as well as Area and Regional Plans were to abide by the findings of this study in the allocation of Building` density and other planning considerations.

In 1994, a similar study was conducted for the design of educational buildings in different parts of Iran, published under the title ‘Climatic Zoning of Iran – Educational Buildings’.

The Research High Council of the BHRC decided to extend the research for establishment of CD tools, to detailed analysis for each of the 30 provinces of Iran, with specific recommendations for its main towns and cities. To date four provinces have been covered – Semnan, Azerbaijan, and Gilan and Mazandaran.

Building Bye–laws were prepared for the purpose of reducing energy consumption in buildings and therefore containing the emission of greenhouse gases. The Nineteenth article of National Building Regulations was framed and approved in the year 1990 by the Cabinet of Ministers as mandatory law[xxiv].

As is evident from the background described above, Iran has not only conducted comprehensive scientific research based on extensive data regarding the contribution of CD in energy saving in buildings; there are also sufficient laws and regulations as well for the implementation of CD in building design and construction that precedes similar work done elsewhere in the world. The United States Green Building Counsel (USGBC) and Leadership in Energy and Environmental Design (LEED) which are America’s leading legal institutions for controlling and monitoring energy consumption in construction activities, energy efficiency in buildings and related activities to reduce the emission of greenhouse gases, came into existence only in the years 1990 and 2000 respectively.

Energy Saving Through CD
This study was undertaken to demonstrate the role and importance of CD in reducing the desired period of use of mechanical systems in different climates, as well as for making available the tools for CD, in the design of residential buildings throughout Iran. A list of criteria that contribute to thermal comfort conditions within a building was drawn up, and given a priority rating. The key design factors for use in CD were grouped as the ‘main objectives of CD’ and strategies devised for the achievement of these listed objectives. Examples below demonstrate the point:

1- In most cities, all over Iran, air temperatures are higher in summer and lower in winter than temperature levels defined by the comfort zone. While this obviates the necessity for exposure of inner spaces to sunlight in winter, the need is quite the opposite in summer, i.e. minimizing direct sunlight within inner spaces. The basic data required for CD in various cities is the extent of the need for exposure to or exclusion of sunlight during the entire year.

2- When outside temperatures are below than temperatures inside a building, opening windows helps in reducing air temperatures within. The information of interest to CD is the extent of outside air ventilation required by buildings in different cities, during different times of the year.

3. In the cold areas of Iran, or during the winter months in most cities, inside and outside temperature differences are normally large. This results in heat loss from the building to the outside. CD requires that the amount of heat loss to be prevented be determined for different cities for what duration of the year.

The answers to these questions were sought through the study of climatic data from 216 meteorological stations all over Iran, and the role of different climatic criteria in determining comfort zones in different climates were studied. The statistical data was analyzed using Giovani’s Building Bioclimatic Chart to compare changes in temperature and relative humidity on a monthly basis over a one-year period in the various meteorological stations, for ‘comfort zone’ temperatures within buildings, using different climatic design building components. Thereon, using hourly temperature data on a monthly basis for the entire year, for the 216 meteorological stations, the annual heating/cooling needs of a building in each of these locations has been calculated.

For example, the results obtained for Semnan, a city located in Iran’s Hot and Dry (desert) zone, are as follows (Figure 1):
– Name of City: Semnan
–  Latitude: 33-35 N
–  Elevation: 1171 m.
– Maximum Air Temperature in hottest month: 37.8 ºC
– Minimum Air Temperature in coldest month: -0.8 ºC
– Conventional heating: 10% of the year
– Active solar Heating: 10% of the year
– Passive solar heating: 21% of the year
– Internal Heat gain: 16% of the year
– Comfort: 22% of the year
– Passive cooling (Thermal High Mass): 18% of the year
– Conventional cooling: 3% of the year

Figure 1: Yearly Thermal Needs of Building Interiors in Semnan

The above figures show that for 77% of the year, in Semnan, comfort conditions can be provided by natural means and without use of non-renewable fossil fuels within a climatically designed building. In other words, this means that with the application of CD recommendations in a building, energy consumption for mechanical heating and cooling of the interiors will be reduced to only 23% of the year (Figure 3). However, buildings not using CD recommendations should be mechanically heated or cooled for 84% of the year (A+B+C +E+F+G) or 61% (84% – 23%) more than climatically designed buildings (Figure 4):

In comparison, the results vary for another city to the south of Iran in the hot zone, as follows (Figure 2):
– Name of City: Khorramshahr
– Latitude: 30-25 N
– Elevation: 5 m.
– Maximum Air Temperature in hottest month: 42.6 ºC
– Minimum Temperature in coldest month: 8.4 ºC
– Conventional heating: –
– Active solar Heating: –
– Passive solar heating: 14% of the year
– Internal Heat Gain: 23% of the year
– Comfort: 21% of the year
– Passive cooling (Thermal High Mass): 29% of the year
– Conventional cooling: 13% of the year

Figure 2: Yearly Thermal Needs of Building Interiors in Khorramshahr

The Table below shows the result of similar calculations for six more stations, which are located in different climate zones of Iran:

This study has established a direct link between a building’s heating/cooling needs and CD. A review of the findings for Semnan and Khorramshahr, shows a close relationship between building design using CD and annual heating and cooling needs:

In Semnan, for 20% of the year, heating is required (Active Solar Heating + Mechanical or Conventional Heating) and another 21% of the year, it is possible to use passive solar energy for heating internal spaces. In total, for 41% of the annual duration, there is an additional heating need to keep internal spaces within a building comfortably warm. These observations lead to the following conclusions in terms of the building’s CD needs:

1. Conservation of heat generated within the building and controlling loss of heat to external surroundings
2. Designing the building for maximizing absorption of solar energy

The above–listed observations, i.e. minimizing heat loss from building and maximizing the utilization of solar energy, are two of the most important considerations in the design of any building in Semnan. However, in Khorramshahr, under ‘normal’ climatic condition, there is no need for heating buildings, but for 33% of the year there is a need for conventional or mechanical cooling and for another 8% of the year there is a need for preventing the effect of warm outside condition on the cool building interior. In other words, for 41% of the year, it is necessary to isolate the internal building spaces from the hot external surroundings, as well as to discharge any heat generated within the building to the outside, to keep the internal spaces cool. Therefore, the main objectives of designing a building to conform to the climatic conditions of Khorramshahr are as follows:

1. Prevention of the transfer of heat from outside air to internal spaces within the building
2. Protection of the building from Solar Radiation during the over heated period of the year

The two examples cited above show that the CD solutions for achieving thermal comfort conditions within buildings in these two cities are quite different, it is therefore logical to conclude that if a building is designed to conform to climatic conditions in Khorramshahr, it would be very different in terms of form and design from a building designed for Semnan.

Calculations made for the 216 meteorological stations in different parts of the country, show that on the whole, for coordinating a residential building design with its local climate, there are a total of 12 main objectives, as described in Climatic Zoning of Iran for Housing and Urban Design. Based on these building design objectives, and building thermal needs, the entire country has been divided into 8 broad climatic zones and 36 sub-zones. Cities located in each of these zones are similar in their design objectives for conforming buildings with thermal needs within a zone and are different from other zones. In other words, from the point of view of architecture, or design in concert with regional climate, eight different climatic zones have been identified in Iran, each with distinct climatic conditions, which dictate different objectives for building design, resulting in distinct building forms and shapes.

These eight climatic zones have been plotted on the geographical map of Iran, to a scale of 1:4,000,000, as climatic zoning for housing and the residential environment. All the 216 meteorological stations have been shown on the map. For each climatic zone, the heating/cooling needs of a building have been tabulated together with the building design priorities for each climatic zone. Additional information presented in the margins of the map, includes, various available methods or design solutions for all climatic design aims.

The Ministry of Housing and Urban Development approved the result of this research as the authoritative document for the Climatic Classification of Iran for Building Design purposes in the year 1990.

Conclusions
The main objective of the research project for the climatic zoning of Iran for housing and the residential environment, was to prepare guidelines and regulations for adapting residential architecture to local climate; however this objective eventually leads to energy efficiency in buildings and in turn reducing the emission of greenhouse gases, thus contributing to the global objective of combating climate change.

The proposed CD recommendations made in the study include criteria for site selection, landscape design, space planning, form and shape of building, housing cluster design, building orientation, orientation of street and pedestrian way, size of openings in buildings and size of sun-shading elements, building’s relation to the ground, building material and colors suitable for the building facade. In view of recent studies and statistics on the contribution of buildings, especially residential buildings, in the emission of greenhouse gases through consumption of fossil fuels for mechanical heating and cooling, the findings of this study and its recommendations are significant. Recent analysis of data collected from 256 meteorological stations all over the country has conclusively demonstrated that use of CD in building design has the potential of significantly reducing consumption of fossil fuels, and must be incorporated in all new building construction, to reduce the emission of greenhouse gases and combat climate change. This has further been demonstrated in the two examples described below, for the cities of Semnan and Khorramshahr, by simulating the energy needs of a building heated and cooled using mechanical Heating/Cooling, as compared to a building using CD recommendations.

As figure 1 shows annual heating/cooling needs of a building in Semnan is:

A. 10% Conventional Heating
B. 10% Active solar Heating
C. 21% Passive Solar Heating
D. 16% Internal Heat Gain
E. 22% Natural Comfort Conditions
F. 18% Passive Cooling (Thermal High Mass)
G. 3% Conventional cooling

The above figures show that for 77% of the year, in Semnan, comfort conditions can be provided by natural means and without use of non-renewable fossil fuels within a climatically designed building. In other words, this means that with the application of CD recommendations in a building, energy consumption for mechanical heating and cooling of the interiors will be reduced to only 23% of the year (Figure 3). However, buildings not using CD recommendations should be mechanically heated or cooled for 84% of the year (A+B+C +E+F+G) or 61% (84% – 23%) more than climatically designed buildings (Figure 4):

Figure 3: Yearly Thermal Needs of a Climatically Designed Building in Semnan