Case Study - Façade Design for a Super-specialty Hospital
Sustainability is and should be a key driver of every aspect of design and passive strategies that are easy to introduce are almost a natural extension of the process of designing . The following play a key role in our methodology.
- Orientation of building on site
- Size of fenestration, shading,
- Understanding the local climate
- Design Strategies for adequate daylight without excessive solar gain
- Envelope design
All of the above form the bedrock of factors to be considered in order to strike a balance between aesthetics, thermal comfort and energy conservation/ lower carbon footprint. Conventional practices of hospital design however often times step away from these aspects due to concerns regarding initial costs and return on investment.
Careful design of the façade is one of those factors that can greatly reduce the energy consumption of a building. Important factors to consider are:
- Access to daylight and views based on space programming
- Incident solar radiation on the surface
- Size of the fenestration (also dependent on orientation)
- Glazing percentage
Use of natural light not only promotes a healthier environment but also helps in designing of artificial lighting which in turn reduces energy consumption. As can be seen the chemotherapy bays have been provided with large windows with louvres that not only prevent the solar gain from the summer sun and reduce solar gain but also give access to natural light. Similarly for the patient rooms full height windows have been provided that have been recessed tp provide shade.
However unlike the first two cases, for the OTs, Prep Recovery and the SICU the size of the openings have been determined by the functionality of the space that does not require large windows.
THE PROCESS
Window performance greatly influences the thermal comfort of occupants. Hence for its design glazing percentages, size of opening, glazing properties such as U-value, SHGC and visual transmittance need to be kept in mind.
- ITERATION 1 : Windows - Ribbon windows Glazing Percentage - 33% Shading - Unshaded
- ITERATION 2: Windows - Ribbon Windows Glazing Percentage - 28% Shading - Unshaded
- ITERATION 3: Windows - Windows designed as per space program. Glazing percentage - 28% Shading - Recessed windows and louvres
It can be seen from the images that as opposed to conventional use of ribbon windows with no shading in iteration 1 and 2, the openings in iteration 3 have been carefully designed keeping in mind the orientation and the insolation radiation on the surface. The results clearly show the reduced insolation on the surface in iteration 3. On comparing iteration 2 and 3, Keeping the glazing percentage the same, one can see that a simple step of recessing the smaller windows and using louvres for larger windows reduces the average insolation radiation on the surface.
The right use of passive as well as active design strategies not only minimizes the impact of the building on the environment but also provides a thermally comfortable environment for its occupants.
