Climate Change & Rapid Urbanisation – Energy & Carbon

This CPD session provides practical guidance on achieving low-energy, low-carbon buildings by integrating passive design strategies, optimized active systems, and renewable energy technologies. Focusing particularly on rapidly urbanizing regions in Africa and developing Commonwealth nations, the discussion addresses the urgent challenge that 75% of buildings to be constructed in Africa by 2050 have not yet been built, presenting both a critical opportunity and responsibility to avoid replicating energy-intensive development patterns. Speakers emphasise the “latecomer advantage” whereby developing nations can leapfrog inefficient building practices by implementing climate-responsive design from the outset, rather than adopting the “Dubai syndrome” of inappropriate glass towers requiring intensive mechanical cooling. Key principles include orientation, appropriate glazing ratios, natural ventilation, thermal mass selection based on climate, and solar shading. The session demonstrates that passive design must be optimised before active systems are considered, that heating and cooling systems should be selected based on climate conditions and source availability (with heat pumps increasingly preferred over fossil fuel systems), and that renewable energy generation—particularly photovoltaic systems with east-west orientation for better daily distribution—should complete the energy hierarchy after demand reduction measures are exhausted.

Outline 

• Context and urgency:
  Africa faces 620 million people without electricity access yet has highest energy costs; 75% of buildings to be built by 2050 not yet constructed representing critical opportunity; rapid urbanisation replicating inappropriate “Dubai syndrome” glass towers in tropical climates consuming 56% of national energy; need for paradigm shift from linear construction thinking to integrated design considering energy analysis from project inception
• Passive design principles:
  Climate-responsive strategies including north-south orientation to minimize east-west solar gain, minimum 40% unbuilt site area, narrow building forms for natural lighting and ventilation, appropriate window-to-wall ratios (not 100% glazing), strategic space allocation with service spaces buffering habitable areas, optimised solar shading designed not to compromise views, natural ventilation strategies, climate-appropriate envelope design with thermal mass for hot-dry climates and lightweight materials for hot-humid conditions
• Active building systems:
  Sequence of first defining performance objectives (environmental targets and indoor conditions), then analyzing site, implementing passive measures, and only then selecting active systems; importance of user control and adaptive comfort criteria; heating systems selection based on demand and occupancy patterns; cooling strategies to address peak demand, refrigerant global warming potential, and urban heat island contribution; ventilation approaches considering site pollution and noise sources with natural ventilation requiring careful design for airflow, acoustic control, and seasonal variation
• Renewable energy and storage:
  Four-step approach from masterplan layout through passive measures and active system optimization to renewable technology selection; heat pumps as emission-free alternative to gas boilers and traditional chillers with efficiency dependent on source temperature (ground/groundwater superior to air) and distribution system design; district heating networks evolving from high-temperature centralized systems to low-temperature (5-20°C) networks with building-level heat pumps; photovoltaic systems transitioning from south-only orientation to east-west “butterfly” mounting for better daily energy distribution matching building use patterns
• Case study applications:
  UN Habitat headquarters Nairobi demonstrating orientation principles with broken building masses creating cool interior courtyards and light wells for deep spaces; British High Commission Kampala showing how when north-south orientation impossible due to site constraints, high thermal mass materials (clay bricks) combined with extensive shading can compensate for east-west orientation; emphasis that passive principles are guidelines not rigid rules requiring site-specific adaptation

Learning Outcomes

The sessions learning outcomes were:

• Describe fundamental passive design strategies applicable across climatic zones including building orientation to minimize solar gain, appropriate window-to-wall ratios, strategic space allocation, natural ventilation approaches, climate-responsive envelope design with thermal mass or lightweight materials as appropriate, solar shading optimisation, and the critical importance of implementing these measures before considering active systems to avoid over-specification
• Explain how buildings achieve indoor comfort and reduce energy demand through passive measures by understanding the sequence of design decisions: defining performance objectives first (both environmental targets and desired indoor conditions), conducting thorough site analysis, maximizing passive strategies, and only then selecting appropriately sized active systems, recognising that user control and adaptive comfort criteria enable lower energy consumption than fixed temperature setpoints
• Understand optimisation of building systems integration with passive design including appropriate heating system selection based on building demand and thermal response requirements, cooling strategies that minimise peak demand and urban heat island effects while considering refrigerant impacts, and ventilation design accounting for site-specific pollution and noise sources with natural ventilation requiring careful consideration of seasonal requirements and acoustic control
• Make informed decisions about renewable energy technologies recognising that heat pumps offer emission-free heating/cooling with efficiency determined by source temperature (ground/groundwater preferred) and distribution system design, that district energy networks are evolving toward low-temperature systems with building-level heat pumps, and that photovoltaic systems benefit from east-west orientation providing better daily energy distribution matching typical building use patterns
• Identify differences between centralised and decentralised energy supply recognising traditional district heating operates at high temperatures (70°C) with significant distribution losses versus modern cold district networks (5-20°C) where heat pumps in individual buildings extract or reject heat as needed, and understand that building-level renewable generation should follow the energy hierarchy of first reducing demand through passive measures and system optimisation before adding generation capacity

Core Curriculum Topics

• Sustainable Architecture
  This session fundamentally addresses energy and carbon reduction through the integrated application of passive design, active systems optimisation, and renewable energy. Speakers detail climate-responsive design principles appropriate for tropical, hot-dry, and hot-humid conditions, emphasizing that sustainable buildings are primarily about design decisions made early in the process. The session demonstrates the energy hierarchy: reduce demand first through passive measures, optimise systems second, and only then add renewable generation, with particular focus on avoiding the “Dubai syndrome” of inappropriate building types consuming excessive energy.
• Design, Construction and Technology
  Throughout the discussion, speakers emphasise the critical integration between architectural design decisions and building services systems, demonstrating that passive design optimisation directly impacts active system sizing and efficiency. The session covers heating, cooling, and ventilation system selection criteria, heat pump technology and efficiency factors, district energy network approaches, and photovoltaic system orientation strategies, stressing that architects must understand these systems from project inception to avoid over-specification and ensure systems work with rather than against building design.
• Places, Planning & Communities
  The session addresses the unique opportunity and responsibility facing rapidly urbanising developing nations, particularly in Africa where 75% of buildings to 2050 are not yet built. Speakers challenge the assumption that development requires replicating energy-intensive Western building patterns, instead advocating for climate-responsive approaches appropriate to local conditions, drawing on vernacular precedents while applying contemporary knowledge, and recognizing that Africa’s “latecomer advantage” allows leapfrogging inefficient development if science-based design principles are applied rather than outdated standards.

SDG Learning Outcomes

• SDG 7: Affordable and Clean Energy
  This session directly addresses expanding access to affordable, reliable, sustainable modern energy while substantially increasing the share of renewable energy and doubling energy efficiency improvements. With 620 million Africans lacking electricity access yet facing highest energy costs globally, speakers demonstrate how passive design dramatically reduces energy demand making renewable supply feasible, how heat pumps and district networks can provide heating/cooling without fossil fuels, and how building-integrated photovoltaics generate clean energy, all critical for providing affordable energy access as urbanisation accelerates.
• SDG 11: Sustainable Cities and Communities
  The discussion emphasises sustainable urbanisation through climate-responsive building design appropriate to rapid urban growth contexts, demonstrating that building and urban planning decisions made today will shape cities for decades determining whether they lock in high energy consumption or enable low-carbon lifestyles. Speakers stress that masterplan-level decisions about layout, orientation, and infrastructure systems establish the framework for individual building performance, and that avoiding inappropriate building types (glass towers in tropical climates) is essential for creating liveable, energy-efficient urban environments.
• SDG 13: Climate Action
  Central to the session is urgent climate action through building sector decarbonisation, recognising buildings account for 40% of energy-related CO2 emissions and that construction decisions made now in rapidly urbanising regions will lock in emissions patterns for 30-50 years. Speakers detail mitigation strategies through passive design reducing energy demand, active systems using heat pumps rather than fossil fuels, and renewable generation through photovoltaics, emphasising that Africa’s opportunity to build correctly from the start rather than retrofitting later represents a critical climate action moment.

The following CPD questions forms part of the learning guide for this session. As different Institutions of Architecture across the Commonwealth have different CPD reporting requirements, it is suggested that you retain a copy of your responses to these questions for your records.

1. Passive Design Application: What are the primary climate characteristics of your region (hot-dry, hot-humid, temperate, etc.), and which passive design strategies are most appropriate? How effectively do typical buildings in your context employ orientation, shading, natural ventilation, and climate-appropriate envelope design?
2. Energy Hierarchy: In your current projects, do you follow the sequence of first minimizing energy demand through passive design, then optimizing active systems, and only then considering renewable generation? What barriers prevent this approach?
3. Latecomer Advantage: If you work in a rapidly urbanizing context, how can you apply the “latecomer advantage” to implement science-based climate-responsive design rather than replicating inappropriate building types? What examples from your region demonstrate climate-responsive approaches?
4. Systems Integration: How early in your design process do you engage with building services engineers to ensure passive design and active systems are integrated rather than working against each other? What changes to your process could improve this integration?
5. Renewable Energy Strategy: For a typical project in your context, what renewable energy technologies are most appropriate considering climate, available sources (sun, ground, groundwater), and building use patterns? How can building form and orientation be optimized to support renewable energy generation?

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