Feasibly integrating renewable energy centers powered by ASHP (Air Source Heat Pumps) within the heart of urban environments is complicated. Finding optimal locations for these units, where they can operate efficiently without performance impacted by local sheltering buildings, poses a unique challenge. Surprisingly, the answer might just lie in an often-overlooked urban fixture: multi-storey car parks.
The United Kingdom has around 6,000 multi-storey car parks, predominantly situated in the centers of towns and cities. These locations are conveniently positioned within dense commercial and residential areas, serving an increasingly dwindling high street. By transforming these spaces into hubs of clean energy production, we can leverage their urban centrality to ensure that renewable energy is generated exactly where it is most required.
Top floors of many multi-storey car parks are often the least utilised, with many remaining empty for extended periods. This underused space presents a perfect opportunity for the installation of air source heat pump arrays. Without the need for extensive modifications, these areas can be quickly repurposed, demonstrating a smart use of urban space that would otherwise go to waste. For fairness, there are towns and city centers that are thriving and continue to have high demand for parking , particularly those with strong cultural and tourist attraction. However using google maps to search city centers for multi-storey car parks, it's harder to find roof levels with cars than completely empty.
One of the critical factors for the efficient operation of air source heat pumps is adequate air dispersion. The roof levels of multi-storey car parks offer a potentially unobstructed environment, ensuring that the rejected air is effectively dispersed into the atmosphere. This positioning mitigates the risk of air re-circulation and reduces the potential for pedestrian discomfort caused by cold air. Paired with the opportunity to use the underutilised roof levels, the heat exchangers are less likely to be highly sheltered from surrounding buildings.
Image - Case study. Exhausted cold plume (orange) showing good dispersion into the ambient environment.
The unique superstructure design, with each level exposed to the ambient environment means the entire car park is naturally ventilated. This raises the opportunity to place the heat exchangers above an opening made in the roof deck, creating a plenum between levels, physically separating the intake and exhaust. Reducing the risk of recirculated air that could diminish equipment performance. In addition, the open design and ample space inherent to multi-storey car parks facilitate the straightforward installation of ASHPs and related infrastructure. This accessibility not only speeds up the installation process but also minimises disruption during enabling works, a crucial consideration in dense urban environments.
Robust construction of multi-storey car parks means they are well-equipped to support the additional weight of heat exchanger arrays and plant equipment. This high load capacity reduces the likelihood of additional structural support, making the installation economical.
Image - Case study. Wind speed and fan velocity section through car park structure. Top slab used as physical separation between heat exchanger intake and exhaust.
Similarities between car park typologies open the opportunity to leverage a typical system approach to project delivery. Plant equipment, secondary structures and enabling works can all be systemised to optimise repeat activities across multiple sites. Optimisations and rationalisations improve the speed, economics, safety and quality by designing the system for fabrication and assembly.
Finally, can we improve the cultural and architectural appreciation of these much unloved buildings by re-purposing these spaces for clean energy production. Can a change in public perception be fostered for a greater appreciation of these structures.
The integration of air source heat pump energy centers within multi-storey car parks offers a solution to the challenges of urban energy production. By capitalising on the unique advantages these structures provide, cities can take a significant step forward in the transition towards sustainable net zero built environments. This innovative approach utilises existing infrastructure but with broader goals of environmental stewardship and urban revitalisation.