District Energy Planning in New Towns
Building ‘new towns’ is not a new concept: new towns have been built throughout history since urbanization began. What is new, however, is the evolving need for expanding the urban places as well as innovative approaches to new towns development.
In my lifetime, 17 new towns have been constructed in Iran. The aim of these new towns’ formation in Iran was to meet various needs: controlling the rapid, informal growth of cities, accommodating the surplus population of overpopulated metropolises, offering affordable housing, and in some cases, providing employment opportunities. Some of the ‘old’ new towns that were transformed into a city during my ancestors’ lifetime – for example, Abadan’s expansion in response to the development of oil resources – are now enjoying economic success. My hope is for the more recently built new towns or those that will be planned during my lifetime to enjoy the same, if not higher, levels of economic and social success by leveraging non-petroleum based resources.
In meeting a multitude of requirements, several questions arise – how do we design the built environment and the infrastructure that serves it (for electricity, heating and cooling purposes) in a way that is climate responsive? How do we design the built environment and the infrastructure to promote ethical sustainability?
The aim of this project is to provide a model for energy systems planning at the community level that maximizes the comfort and living conditions of the occupants while reducing the energy demand of the built environment, thus minimizing negative impact on the environment. A four-step approach is used to achieve these objectives.
First, the existing buildings’ energy performance is optimized based on architectural and passive strategies that are appropriate for the local climate. The hourly load per square meter for the base case and the optimized case are simulated using TRNSYS and TRNLizard. In the second step, the hourly load results are post-processed in order to create the building load profile for each scenario. For the optimized case with a central heating system, an estimation method using Gaussian normal distribution is implemented to calculate the building’s load profile based on the appropriate diversity factor. Once demand is reduced as much as possible and the building load profile is developed, the next step is to consider the supply options that meet the reduced energy demand at the building level. Finally, the district energy supply options are considered for the base and optimized case. Modeling and simulation of the energy supply options in the last two steps are performed in Simulation Studio.
The outcome of the four-step approach is to deliver a set of guidelines for energy-efficient building design, and a comparison of different district energy options for new town development. The assessment is made based on peak demand, energy efficiency, and primary energy use of each scenario compared to the base case.
It is shown that certain strategies can shift the demand from peak times in a typical day, reducing the stress on energy production plants. These strategies include: optimization of the heating systems’ distribution temperature, storage of hot water during off-peak times to be used during peak periods, and synergies offered by use of a district heating and cooling system. Through this process of energy demand management, we achieve the following goals: less need for large power plants designed for peak power, more efficient energy production, and maximized use of renewable energy resources.
The new town outside Shiraz in Iran is selected as a case study to show the application of the developed model to energy management in an existing urban setting with residential and retail units. The project can also serve as a guideline for energy planning of future new towns. At each step of the design process, the experience of the occupants – including the cultural norms and thermal comfort levels – is a decision factor that shows it is possible to live comfortably, perhaps even luxuriously in some houses, while minimizing dependence on fossil fuels.
Project mentor: Monika Schulz
Elmira Reisi is Iranian and did her Bachelor of Applied Science in Engineering Science with a Major in Energy Systems Engineering at the University of Toronto. She is part of Engineers without Borders EWB and Alumni of the School for Social Entrepreneurs Ontario.