Chapter 4. Energy efficiency and design measures
4.4 Energy Efficiency and design measures
City planning is one of the major drivers of enhancing the energy performance in urban areas. It is therefore essential that city officials ensure that city planning accommodates and integrate a variety set of policy goals in that regard. The decisions on urban density, mixed uses and in general the form and functional configuration of cities can have a direct impact on building heating and cooling needs, the cost effectiveness of public transport, and the vulnerability of the built environment to extreme weather conditions.
The overall message is that, the energy demand and supply needs can thus be reduced by design as much as or even more through integration of new technologies (IEA, 2012).
As discussed previously, the influence of urban development policy in regard to energy efficiency is to a large extent on two sectors, namely; building sector and transport sector. The building sector is the primary energy consuming sector at the city level.
Energy efficiency policies for this sector should therefore be developed early on in the design of urban policy packages. As an example, the policy packages, therefore requires to include building energy codes as well as energy labelling schemes that aim to reduce the energy demand of both new and existing buildings, without compromising comfort levels.
Transport is another important energy consuming sector at the city level, which requires a similar considerations early in urban policy design. Transport policy to reduce energy consumption comprises of different solutions and often includes the implementation of efficient, high quality and safe public transport systems; schemes to discourage the use of personal vehicles, and policies that turn multi-modal trips into seamless journeys.
Furthermore, it includes measures for the minimization of distances and reducing the need for movement through appropriate functional planning of cities. In this context, the mixed use areas can also save energy by reducing the average distances city dwellers need to travel on a normal day (IEA, 2012). Policies to ensure reliable energy supply and sustainable energy generation will generally be designed and implemented at the local level. However, the impacts of national and regional policies on the overall urban policy and planning process is crucial. Energy wise, the policies should therefore create an effective link between national, regional, and local needs. Examples of the most important areas to address include city development planning, building energy efficiency, transportation efficiency, as well as energy generation, distribution and delivery. Furthermore, the analysis of such policy areas should also employ a cross-sectoral approach. The link between energy and transport for example is apparent, but
less obvious interdependencies can also be important, such as the interplay of energy policies with waste and water management.
When it comes to urban development, for example, policy-makers should include energy demand and generation requirements in all stages of city planning policy design. In planning and development of more efficient cities, not only traditional technologies, but also passive solutions shall be considered. Examples are taking into account the local climate and natural environment characteristics towards enhancing the utilization of passive energy gain and minimization of loss of energy (IEA, 2012).
In this context, in order to achieve more energy efficient cities, laws and regulations should play a vital role. For example, in 2000, the city of Barcelona introduced its mandatory solar ordinance . According to the law, all new housing, offices, restaurants, and public buildings have to install solar hot water systems if they use substantial amount of hot water. Old buildings also have to be fitted with solar hot water systems when they are refurbished. In Japan, for instance, about 10% of all dwellings have their own solar hot water systems. In German cities, solar PV panels are becoming
commonplace, despite the country s climate. This is primarily due to the German government s supportive legislation, which offers fixed subsidies and favourable tariffs for owners of PV roofs. This policy has led to a massive growth in demand for solar PV technology across the country. Similar policy measures have been introduced in Austria, France and Spain (Khalil, 2015). In regard to the policy development as well as
regulatory frameworks, there is always a relationship between the scale of the environmental burdens and the appropriate roles of different levels of government.
Some governance failures can be traced to a mismatch between the scale of the problem and the scale at which the response has been articulated. For example, local governance should not be expected to reduce the carbon emissions voluntarily, although it can be very appropriate for driving local water and sanitation improvements.
Global governance, on the other hand, is clearly needed to help develop institutional mechanisms to reduce contributions to global climate change, but it is inappropriate for developing institutional mechanism for managing local water and sanitation systems. On the other hand, reducing local environmental burden often requires support (or at least the absence of opposition) from global processes and institutions, while response to global burdens often need to be rooted in local agency. Moreover, cities and their needs are complex, and the traditional, departmentally organized approach to city governance needs to be rethought to enable more holistic solutions on the one hand and more
responsiveness and accountability to citizens at a local level on the other (GlobeScan and MRC McLean Hazel, 2007).
In planning for energy efficiency in urban context, a particular role is accorded to municipalities. Brandoni and Polonara (2012) addresses the importance of municipal energy planning processes especially in identifying the crucial aspects in energy consumption as well as assessing the most suitable energy-saving initiatives and
identifying renewable sources that can be more properly exploited in a given local area.
Williams (1999), however, questions the power of the (local) planning system. Williams considers the process of policy implementation as responsible for the divergence between theory and planning practice. In many planning systems, local policy making takes place within policy regulations from higher tiers of government that determine the range of local options (van Stigt, Driessen & Spit, 2013). According to Bulkeley and Betsill (2005), solutions remain tied to the local level instead of exceeding the local frame due to the neglect of interactions of economic, social and political processes across different governance levels and systems as well as gaps in cooperation at the regional level and among constituent municipalities (Geerlings & Stead, 2003). Furthermore, Brandoni and Polonara (2012) consider coordination at the regional and national level as fundamental to enable municipalities to concentrate their efforts on their agenda (Große et al., 2016).To conclude, ambitious and purposeful municipal energy planning requires, on the one hand, policy-wise support from the national level and, on the other hand, coordination at the regional level. This implies examining governance structures and their influence on urban form in more depth to identify and establish helpful governance structures Schwarz : .
Urban energy systems are highly complex, span over multiple physical and temporal scales, and involve a multitude of actors. Today, urban planners are regarded as key actors in the process of developing low-carbon cities, and new decision support methodologies are required to assist them in this task. Figure 82 gives an insight of the main urban energy stakeholders and their potential contribution towards improving energy efficiency initiatives in cities (World Bank, 2010).
Figure 82. Urban energy efficiency stakeholder matrix
Source. UN-HABITAT (2012), adopted from World Bank, 2010
There exist a multitude of planning instruments in which the topic of urban energy efficiency planning can be integrated. Additionally, there should also be a clear contribution by and integration of different actors from the national to the very local level with adequate steering modalities (i.e. both bottom up and top down) accompanied by dedicated legal instruments and enforcement measures. Correspondingly, deep knowledge about the relevant actors and the relevant planning and legal instruments are critical in the context, while improving the planning system.
Focusing on the local context of Iran, in order to create legal frameworks and enforce the implementation of new planning measures in urban development practices, a multilevel interaction among authorities on different levels is required. The same applies to planning instruments and enforcement measures. Studies on current situation (chapter 3) showed a not effective interconnection of actors and instruments in different levels of planning. Here and in accordance to the analysis carried out in the previous section, a modified conceptual interactive model of actors and instruments are presented in Figure 83. The figure conceptually demonstrates, how influential actors and instruments can effectively be coordinated, when it comes to planning for energy efficiency in cities. One core idea is the creation of multilayer coordinated structure with both top-down as well as bottom-up modalities.
Stakeholders Contribution
- National agencies and authorities
- State agencies - Regional agencies - Municipal agencies - Private sector - NGOs
- Investment & planning initiatives
- Research & Demonst-ration
- Education & inspira-tion
- Legislation - Market instrument
Against this backdrop one can propose a set of common policy and regulation instruments and tools which can potentially increase the implementation of energy efficiency in the process of social infrastructure planning lacking in the local planning context. These include: energy regulatory policies; mandatory standards and codes;
labels and certificates; financial facilitation schemes; and awareness-raising and capacity-building initiatives.
A survey of pertinent results within the literature indicate that the integration of spatial energy efficiency measures can highly impact the energy performance of cities. Urban development plans such as master/comprehensive or detailed plans – as the main statutory development roadmaps, which steer the future physical and functional development of cities – are the best spot to integrate new energy and environmental measures. This is even more crucial in urban growth areas due to their higher physical development potential. Identification of concrete planning and design measures and their potential impact and contribution on energy savings in different sectors (building and transport) is an important dimension that recommendations have to take into account.
A properly integrated development plan requires not only considering the design of buildings (in a physical sense), but also integrating people and places, movement and urban form, nature and the built environment (Urbandesign.org, 2012). From a holistic urban design perspective, in order to reflect the uniqueness of a city, a district or a neighbourhood, a crucial factor is to analyse the local conditions, the climatic,
environmental, social, cultural and political context. The combination of these factors, helps planners to choose appropriate development scenarios, compatible with local features and characteristics. Doing so also positively affects the acceptancy of a plan by end users and other involved actors in the process of urban development.
When it comes to enhancing energy efficiency in social infrastructures, several technical, behavioural and planning aspects are influential. However, the focus on this research is on the form and functional dimension of spatial planning and the discernment of their effect on energy efficiency.
This refers to the physical layout and design of social infrastructure built spaces, such as densities, uses, street design and layout, transport systems, building typologies in different scales (Dempsey et al. 2010: 22). Different formal and functional configuration of cities affect users life style and, as a result, levels of energy consumption in relation to
social infrastructures. Considering energy efficiency in social infrastructure planning as the main thematic focus, this research emphasizes the following two dimensions:
A. planning measures to improve the energy performance of social infrastructure buildings
B. planning measures for social infrastructures to improve energy efficiency in the transport/mobility sector
A detailed description of recommended spatial measures in both dimensions are presented below67.
A. Energy efficiency in the building sector - Planning measures to enhance energy efficiency in social infrastructure building structures
The geometry and design of buildings is a key aspect impacting energy consumption levels. Factors such as building density and types, height of building, distance to adjacent buildings, vegetation, orientation etc. will influence solar potential and shading, which directly affect the heating, cooling and lighting demand of buildings. Several researches and pilot projects have analysed these measures for residential buildings. However the potential saving effects of these measures are often neglected regarding other physical structures such as social infrastructures. Environmental planning and configuration of these built structures allows solar gain which reduces the heating demand especially in colder climates.
However, shaded objects may have lower cooling demand especially in hotter climates and during summer. Sun light and the configuration of openings can also impact on absorbing adequate natural light and therefore less energy demand for lighting purposes in the building. Influential design elements in this regard are the orientation to the sun, shading consideration, building compactness, openings and building facades, which impact the passive heat and light gain of a building. Urban planning and design strategies allow considerable energy savings by applying the above mentioned measures at little or no extra costs. This covers measures to minimize the thermal loss and measures to maximize passive energy impacts.
67 Introduced measures in the following part of the research are calibrated/adapted to the conditions in District 22 of Tehran, how-ever can be applied in other similar cases.
A.1. Minimization of thermal loss
Optimizing the social infrastructure s building volume
stabilizes the building s thermal behaviour through measures such as compactness and surface to volume ratios. Applying this measure reduces thermal loss through building surfaces and efficiently regulates the interior climate against outside temperatures and seasonal or daily temperature peaks. One example is the surface design and materials which can reduce the impact of outside climate on interior spaces. This measure
shall be jointly considered with architectural design. In essence, the compact building form hides building volumes from climate effects and thus helps avoid thermal loss (Brunner et al., 2009). The thermal envelope (roofs, facades and ground-slaps) is the most important element to control the energy benefits and loss in the built structures such as social infrastructure buildings. Furthermore, due to the high demand for quality in construction and detailing, the surface is a cost intensive building element. By
optimizing the surface area through compactness, building costs can be reduced and a permanent desirable interior climate can be achieved.
In the local context of Iran, considering the local climate conditions, the A/V ration should not exceed 0.65 for buildings with 3 external walls and 0.5 for buildings with 2 external walls.
A.2. Maximizing passive energy impact Maximizing passive energy use in the social
infrastructure buildings can be achieved by adapting the building form to use natural energy. The main natural energy sources are the sun and wind. Passive energy helps to reduce the active energy demand for cooling, lighting and heating and, in turn, CO2 emissions.
The planning and design of social infrastructure building structures ought thus to be oriented towards maximizing the sun exposure in winter to reduce the heating demand and minimizing it in summer to reduce
the cooling demand by shading. Solar radiation in Tehran is very intense, meaning that the sun is a valuable source of energy for heating. What is more, the high solar incidence
Figure 84. Optimization of surface & volume
A/V=0.85 A/V=0.61 Source. Khodabakhsh,
2017
Figure 85.Orientation and sur-face design and passive energy
absorbance
N 20°
Source. Khodabakhsh, 2017
can create a surplus of heat, especially in summer. This fact must be considered in the planning of building volumes and south orientated surfaces to absorb solar energy for natural heating purposes during cold days. In addition, the facade should be designed with shading devices to combat over-heating in summer. Regarding the location on a slope, south- or southwest facing slopes are
particularly suitable due to greater solar gain of the social infrastructure buildings (Stadt Essen, 2009: 5).
In addition to solar energy, wind has a great potential for natural ventilation of indoor and outdoor spaces. This shall be harnessed through jointly design of street and buildings layouts and orientation as well as openings of the social infrastructure buildings to channel the wind (canyons). Cool winds shall be harnessed for ventilation and cooling in summer by avoiding buildings in breezeways and by blocking hot winds with buildings and building groups.
Notwithstanding the importance of climate response design in the traditional
architecture and urban development in Iranian cities, consideration of climate factors (i.e. sun and wind) has been reducing during the time. This evolution from traditional climate responsive urban form to more recent fragmented and unstructured patterns can be traced in the following eras:
The old traditional compact inner area urban blocks which is a courtyard-struc-ture urban block. In this common type of blocks, ventilation is through wind catchers connected to Ivans, basements, and courtyards.
Middle area urban blocks, produced by reducing the size of the old large tradi-tional urban blocks. This is a type that was restructured in the first decades of twentieth century in more affluent neighbourhoods. Altogether, in this typology accesses were opened, and although the structure is more exposed to excessive heat and glaring sun, it utilizes more natural light and air flow.
After a few decades, in mid-twentieth century a more rectangular residential block based on courtyard row houses took shape. Plot of land was divided into two pieces, and the building mass was constructed on the one side of the plot,
×
×
× ×
× ×
Figure 86. Prohibiting blocking by other physical structures
Source. Khodabakhsh, 2017
looking to the south. The streets were widened to improve access to motorists.
Decline in household size and changes in socioeconomic and cultural conditions in modern Iran led to emergence of this new block form. In response to climatic issues, the structure is integrated with mechanical ventilation.
Since the last three decades, following the act of selling building density and de-veloper s activity in the construction of apartment blocks, a low-quality multi-storey building form in different climatic regions of the country has been domi-nant. Climatically and culturally, this structure is incompatible with the urban fabric of the hot and arid zone cities (Tavassoli, 2016).
Traditional planning and design principles addressed above, have great potential to be reawakened and adapted in the contemporary development of social infrastructures with the aim of maximizing the utilization of passive energy.
The orientation and dimension of streets affects their passive energy absorbance capacity. In the case of Tehran, east-west orientation of streets promotes the north and south solar exposure of the buildings, which can be more readily controlled as a result of the greater solar altitude (according to Givoni, 1998: 368). Streets running north-south have better shading conditions in summer and better light conditions in winter. This is a conflict that can be solved by diagonal streets, orientated northeast-southwest (Ibid.).
Such street orientation allows natural ventilation by afternoon and evening winds for the social infrastructure buildings.
Another strategy which is briefly mentioned above, is the integration of new technologies as an additional layer of design. One example is the installation of external shading devices, which help in regulating solar heat gains of the social infrastructure building.
Especially in hot summer regions such as Tehran, shading through curtains or covering of open spaces creates micro-climate benefits.
An element from vernacular architecture is the covering of courtyards through mechanical or textile elements which reduces the direct solar impact and creates a
comfortable semi-open space. These elements can be combined with the effect of light guidance (e. g. for naturally shaded space in winter) or the energy benefits of
Summer Winter
Figure 87. Shading regulation and passive energy absorbance
Source. Khodabakhsh, 2017
Regulations and measures generated in an urban planning and design process ought to be compatible with local topography and climate. This shall be implied in building and street design. The aim is to maximize the benefits of local environmental features and minimize their negative effects (i.e. intense topography or climate conditions).
One example are linear building arrangements, as a commonly used pattern in Tehran.
This arrangement makes use of passive energy by maximizing the southern orientation of their facades. At the same time, this linear arrangement bears conflicts with
topographic and social aspects in District 22. Privacy requirements contradict the need for opening up the facades and the high cooling demand in summer need to be
considered in the design as well. Furthermore, the intensive land demand of linear building types runs against overall energy aims at the urban scale. Given the high costs of execution and the need to protect both the natural climate and resources, topographical interventions, which prepare land for large linear building arrangements, would be more effective if economic and ecological effects were considered.
In this context, vernacular building types offer well adapted regional building typologies.
The compactness of the traditional courtyard housing scheme is perfectly suited to dense and compact urban form. The shaded courtyards and their micro-climate deliver thermal comfort via air circulation catalysed by the building morphology. But the sun impact and energy gain in winter periods is reduced to southerly oriented subzones. Such typologies can be integrated in the planning and design of social infrastructures.
Figure 90. Building and plot typologies in relation to environmental benefits
Source. Pahl-Weber et al., 2013
Building volumes in the compact urban design scheme need to take advantage of their positioning. In the case of District 22, the plot design of the majority of social
infrastructures is based on a north-south orientation, determined in the urban design layout.
Introwerted East-west oriented South oriented