Facade Gen AI – IAAC BLOG

Team member(s): Deeksha K O, Yichen Lu, Farida Fidvi and Bao Trinh
Modified by Deeksha K O on July 12, 2024

Our Generative AI seminar is dedicated to supporting our work at AIA studio, which focuses on sustainable design. Our task is to collaboratively generate a dataset of at least 800 facade images using generative AI techniques. This dataset will be an essential resource for us, enabling advanced research and development in sustainable architectural design and analysis within our studio.

This journey involves creating synthetic data to produce a photorealistic facade image dataset. The ultimate goal is to generate depth maps for AI machine training, allowing users to input their facade images for subsequent solar radiation analysis.

Problem Statement

In the 1930s, Vienna embarked on the “Red Vienna” social housing movement, creating a significant legacy of public housing infrastructure. Following the devastation of World War II, the city undertook a rapid reconstruction effort, constructing approximately 9,000 housing units per year to address the urgent need for accommodation. These post-war buildings, while pivotal at the time, may now fall short of current physical and social standards, necessitating an evaluation and potential upgrade to meet modern requirements.

Our research targets these aging structures, utilizing the capabilities of a large language model (LLM) to focus on two primary objectives:

Post-War Building Evaluation: Assess the current state of post-war buildings in Vienna to identify physical integrity, energy efficiency, and social suitability deficiencies.
Facade Utilization for Environmental Solutions: Explore innovative facade designs and retrofitting techniques to enhance the environmental performance of these buildings, addressing issues such as energy consumption, urban heat island effect, and aesthetic integration with contemporary urban landscapes.

By leveraging the analytical power of LLMs, we aim to develop actionable insights and strategies to rejuvenate Vienna’s post-war housing stock, aligning it with contemporary standards and contributing to sustainable urban development.

LLM/ RAG KNOWLEDGE POOL

Post-War Building Evaluation:

Dataset 01: Background Research – Building a Sustainable Approach on a Post War Housing Structure.

Facade Utilization for Environmental Solutions:

Dataset 02: Background Research – Energy Reduction Related to Facade Design in Urban Environment.

RAG RESEARCH QUESTIONS:

How might a World War II-era social housing development present challenges in today’s society?

ANSWER:

Post World War II, many countries in Europe experienced a housing crisis due to the devastation caused by the war and the subsequent economic recovery.

The need for rapid construction of large numbers of affordable homes led to the development of high-rise tower blocks and dense housing estates. While these projects were initially seen as a solution to the housing shortage, they often became problematic over time.

One of the main issues with post-war social housing is the lack of maintenance and investment in these areas. As these estates aged, they suffered from

poor maintenance, leading to a decline in their physical condition. The initial vision of creating vibrant communities often failed to materialize, as the design of these estates did not adequately consider the social aspects of living. The lack of mixed-use development and inadequate provision for amenities and services resulted in isolated and sometimes unsafe environments.

Another problem is the lack of flexibility in the design of these housing projects. The rigid layouts and standardized designs often failed to accommodate changing societal needs. The one-size-fits-all approach did not consider the diversity of household sizes, compositions, and lifestyles, leading to a mismatch between the housing stock and the actual demands of the residents. This resulted in underoccupation or overcrowding, putting pressure on the available social housing stock.

Additionally, the poor physical condition and social issues associated with these estates led to a negative perception and stigma attached to social housing. This, in turn, created difficulties in attracting investment and maintaining the desirability of these areas, perpetuating a downward spiral. The

lack of amenities, inadequate transportation links, and absence of mixed-income communities further exacerbated the social and economic problems.

Finally, the centralized planning approach, common during this period, often resulted in a top-down decision-making process that disregarded the needs and aspirations of the future residents. This lack of community engagement and empowerment meant that the resulting housing projects were not always aligned with the actual demands and preferences of the people who would inhabit them.

In summary, the challenges of post-war social housing include inadequate maintenance, a lack of flexibility in design, poor physical and social conditions, negative perceptions, and a top-down planning approach that failed to involve the community. These issues have led to the marginalization and decline of many housing estates built during this era

What effective strategies would be for renovating old housing in the Vienna/central Europe region to enhance energy efficiency?

ANSWER:

Renovating old buildings in an energy-sufficient way is a complex process that requires careful planning and consideration of several factors. Here are

some suggestions to renovate an old housing unit in Vienna while focusing on energy sufficiency:

1. Energy Assessment: Start by conducting a thorough energy assessment of the building. This will help identify areas where energy is being wasted and potential improvements. An energy auditor or architect specializing in sustainable renovations can assist in this process. Common issues in older buildings include inadequate insulation, single-pane windows, inefficient heating systems, and air leaks.2. Insulation and Air Sealing: Improve the building’s envelope by adding insulation to walls, floors, and attics. Pay attention to details such as window and door seals to minimize air leakage. Consider using eco-friendly insulation materials like cellulose or sheep’s wool.

4)What sustainable approaches can be used to renovate old building structures in Central Europe, particularly to mitigate the urban heat island effect?3. Window Replacement: If the existing windows are old and inefficient, consider replacing them with high-performance, double or triple-glazed windows.

This can significantly reduce heat loss and gain. Try to maintain the historic character of the building by choosing appropriate window styles and materials.

4. Efficient Heating and Cooling Systems: Upgrade the heating system to a more efficient one, such as a condensing boiler or a heat pump. Consider using renewable energy sources like solar thermal or geothermal systems. For cooling, install energy-efficient split systems or passive strategies like shading devices and natural ventilation.

5. Renewable Energy Integration: Explore the possibility of installing renewable energy systems, like solar panels on the roof, to reduce the building’s reliance on fossil fuels. The excess energy can be sold back to the grid under Vienna’s net metering regulations.

6. Sustainable Materials: Choose eco-friendly and recycled materials wherever possible. This includes flooring, countertops, plumbing fixtures, and interior finishes. Using sustainable materials reduces the project’s environmental impact.

7. Ventilation and Indoor Air Quality: Ensure proper ventilation by installing mechanical ventilation systems or optimizing natural ventilation. This is crucial for maintaining indoor air quality, especially in tightly sealed buildings.

8. Lighting Upgrade: Replace old incandescent bulbs with energy-efficient LEDs or CFLs. This can reduce electricity consumption for lighting by up to 80%. Consider using smart lighting controls to optimize usage.

9. Renewable Water Systems: Install water-saving fixtures and consider renewable water systems, such as rainwater harvesting, for flushing toilets and irrigation purposes.

10. Behavioral Changes: Encourage residents to adopt energy-sufficient behaviors, such as turning off lights when not in use, using sunlight instead of

electric lighting, and reducing excessive consumption.

Renovating old housing units requires a delicate balance between preserving the building’s historic character and introducing modern, energy-efficient technologies. Working with experienced professionals who understand both sustainability and historic preservation can help achieve energy sufficiency while maintaining the building’s charm. Additionally, consider encouraging residents to participate in the renovation process and educate them about energy sufficiency to create a collective sense of responsibility.

What are sustainable approaches to renovating old building structures in Central Europe, particularly to mitigate the heat island effect?

ANSWER from a merged json:

Renovating old buildings in Central Europe to improve their energy performance and mitigate the urban heat island effect can be achieved through a combination of sustainable strategies. Here are some common approaches:

1. Insulation Upgrade: Enhancing the thermal envelope is a crucial step. This involves adding external or internal insulation to the building envelopes, focusing on the roof, walls, and windows. External insulation systems, also known as “thermal wraps,” are often used in renovation projects to improve

energy efficiency without compromising the historic facade aesthetics. Common materials include mineral wool, polystyrene, or cellulose fiber.

2. Window Replacement: Upgrading old single-pane windows with energy-efficient double or triple-pane units significantly reduces heat loss and gain. This measure is especially effective in mitigating the urban heat island effect, as windows are responsible for substantial heat transfer. Historical preservation regulations often require the use of visually similar window profiles while incorporating modern insulating glass units.

3. Passive Cooling and Ventilation: Enhancing natural ventilation and passive cooling techniques can help mitigate the urban heat island effect. Strategies include designing or retrofitting existing buildings with strategic openings, shading devices (external awnings, blinds, or louvers), and cross-ventilation systems. Night purging, which involves opening windows at night to cool the building naturally, can be an effective strategy in temperate climates.

4. Green Roofs and Urban Greening: Installing green roofs or vertical gardens on renovated buildings can help cool the surrounding environment. Green roofs reduce the urban heat island effect by absorbing sunlight and releasing moisture, leading to a cooling effect. Additionally, greening urban spaces,

such as installing parks, planters, and green infrastructure, can provide shade and evaporative cooling.

5. Renewable Energy Integration: Integrating renewable energy systems into renovated buildings can improve their energy sustainability. Solar panels, both photovoltaic for electricity generation and thermal for hot water heating, are common additions. Solar shading devices that track the sun’s movement

can further reduce heat gain and provide a renewable energy source.

6. Smart Materials and Technologies: Using smart materials and technologies can make renovation projects more sustainable. This includes installing intelligent building management systems to control lighting, ventilation, and temperature. Phase change materials (PCMs), which store and release thermal energy, can be integrated into walls or ceilings to improve temperature regulation.

7. Historic Preservation: Renovating old buildings while preserving their historic character requires careful consideration. Often, a balance needs to be struck between maintaining historical integrity and implementing modern sustainable solutions. This may involve close collaboration with architects, historians, and conservation experts.

8. Urban Planning and Design: Mitigating the urban heat island effect also involves urban planning and design strategies. This includes designing compact, walkable neighborhoods with efficient public transportation, reducing the need for private vehicle use. Strategic placement of trees and green spaces within urban areas can also provide shade and cooling.

9. Sustainable Materials and Construction Techniques: Choosing sustainable materials with low embodied energy and implementing eco-friendly construction techniques are essential aspects of renovation projects. This may involve using recycled materials, optimizing waste management, and employing efficient construction methods.

10. Energy Recovery and Efficiency: Recovering and reusing energy within the building can further enhance its sustainability. This can be achieved through heat recovery ventilation systems, smart heating and cooling controls, and optimizing HVAC systems.

When renovating old buildings in Central Europe, it’s essential to consider the specific local regulations and cultural significance of the structures.

Sustainable renovation practices not only improve energy efficiency but also contribute to creating healthier and more comfortable indoor environments while mitigating the urban heat island effect.

Studio Concept :

The idea is to hand-sketch louver lines over a facade image to demonstrate potential energy reduction. The user input will be a facade elevation photo and a set of line sketch on the facade. A instant feedback will be a pair of heatmap shows before and after louvers. We will further decoding the color code and calculation the radiation reduction.

User Inputs :

Facade Image Upload: The user uploads an image of the building facade.
Hand-Drawn Sketches: The user applies hand-drawn sketches on the facade image to propose modifications, such as adding louvers, green walls, or other elements.

Output:

A visualization of the modified facade with hand-drawn elements.
An estimate of the energy reduction percentage achieved by the proposed modifications.

Our model is designed to allow users to input a facade image and apply hand-drawn sketches. Based on these inputs, the model will analyze the modifications and provide an estimate of the energy reduction percentage.

However we would need a facade dataset which as at leat 800 images!

Problems with using the Realistic Facade Image Dataset :

We faced a threefold challenge in creating a rich and relevant dataset for mapping facade images to depth maps using the pix2pix framework:

Non-Front View Images:
- Most images of target buildings were not captured from a direct front view, distorting architectural details needed for accurate depth maps.
Obstructions:
- Front view images often contained obstructions like trees and street lines, complicating the generation of clear depth maps using tools like DepthAnything.
Irrelevant Public Datasets:
- Public datasets, such as the segmentation dataset on Kaggle, do not match the architectural style of our target buildings, leading to poor generalization.

Attempts at co-relating input Facade image to Synthetic Facade Dataset :

Attempt 01- Image to Image with ControlNet Canny_XL:

We used ControlNet Canny XL to generate realistic facade photographs from synthetic depth maps, and color masking with Grasshopper to ensure clear lines. Prompts were generated using OpenAI Lora for accurate captions. However, the resulting images didn’t match the disheveled architectural style of post-war buildings.

Attempt 02- Facade Image Generation using LOOKX:

We used LookX with depth maps as base images and realistic photos of target buildings as style images, along with 10-12 token prompts. This method produced ideal photos but was too time-consuming, expensive, and often generated incorrect results, such as eaves being misinterpreted as windows.

Attempt 03- LORA and ControlNet Canny :

To achieve our goal of generating depth maps from real facade inputs, we adapted a LoRA workflow involving steps such as – dataset creation, training, and testing. Initially, we used LookX to generate realistic facade images from depth maps with style references and prompts. However, LookX was unsuitable for mass production, as each depth map had to be individually uploaded and prompted, making it impractical to create a larger dataset of 2000 images. Consequently, we switched to training our LoRA model using the smaller dataset generated from LookX, enabling more efficient and scalable dataset creation.