Design Journal Entry - Module 4

Journal Entry For
Module 4 - Conceptual Design - Building Context & Passive Design

For 2 or 3 units

  • Create and share a Psychometric chart for your project location.

The project location I’ve chosen is currently a soccer field and green space to the immediate south of Vista Hermosa Natural Park, just across the 110 freeway from downtown Los Angeles. I’ve chosen this site not because of favorable weather conditions or especially wonderful views, but because I’d like the challenge of creating a nature-inspired structure that can help beautify a dense, urban environment. As someone from socal, I’m anticipating mild winters and very warm summers in this location.


This soccer field provides enough flat land area for the footprint of a reasonably sized high-rise building. While much of the surrounding area isn’t exactly pretty, a building here will overlook the surrounding park, which itself will allow the building’s occupants ample access to green space and recreation The building will also have a close-up view of Los Angeles’ downtown skyline, as it is only a few blocks away.


As can be seen in this screenshot, this location balances immediate proximity to downtown Los Angeles with having some nearby greenspace. I think this is a reasonable location for demonstrating a sustainable highrise building.


The average temperature is only within Climate Consultant’s “comfort range” during the summer, which has average highs in the high eighties Fahrenheit. It looks likely we’ll need active cooling during summer days and active cooling during winter days (and especially winter nights if the building is occupied 24/7.


This psychometric chart shows that we can hit a maximum of 82% comfort time without active heating and cooling measures. I’m tempted to use such a strategy while removing low performers like wind protection of outdoor spaces and humidification.


Instead, I think I’ll go with something like the above strategy. Using active heating allows us to hit 97% comfort time. I’m hoping that with enough PV performance, we can exclusively use site-powered electric heaters, allowing us to avoid burning gas or using power from the grid.

  • Test 2 different alternative conceptual building forms using:
    • Insight analysis to predict the energy performance each of the forms
    • I’m analyzing two similar forms at varying levels of detail. In my head, I’m picturing a flower-shaped highrise building with a tall, thick “stem” and a several cantilevered “petals”. For the first conceptual building forms, I’ve made a very crude approximation of this design using two cylinders, a tall, narrow one to serve as the tower and a shirt, wide one at its top to represent the bloom or canopy. This simple model looks more like a toadstool than a plant, but I still kinda like it, and I imagine it will provide lots of good surface area for PV performance.

      The second form is much more flower-shaped, with different petals being modeled using partial ellipses. The tower “stem” is also slightly canted inward from its base to provide more artistic flourish.

      Both forms are 165’ tall, each floor level being 15’ high. The designs are referred to as the “toadstool” and the “flower”, respectively. The base of each tower is 80’ in diameter and the top level of each is 200’ in diameter.

      I’ve chosen the same input parameters for both forms’ Insight models. I’m surprised by just how different the two forms’ EUI is!


      Unsurprisingly, building orientation has no real effect since both forms are axisymmetric. Window shades in all directions and infiltration parameters are also essentially negligible in their effects, so their defaults were left alone. I also left the default parameters for HVAC alone, as recommended by the professor.

      I assumed a 12/7 operating schedule and a range of 50-30% WWR for all directions. Elsewhere I chased as much efficiency as I could, selecting high-efficiency options for HVAC, 20.4% PV panel efficiency, 90% PV roof coverage, 20-30 year PV payback limit, daylighting and occupancy controls, maximum plug efficiency (0.6 W/sf), insulated roofing (at least R10), walls made of R38 wood or better, and Trp LoE window glass in all directions.

      I thought that the results would be pretty similar, but I was mistaken!


      The flower design appears to be clobbering the toadstool, with EUI about five times less! The toadstool has an EUI of 25.8 kBtu/sf/yr whereas the flower has only 5.30 kBtu/sf/yr.


      ^ EUI for the toadstool


      ^ EUI for the flower

      Both designs are well below the ASHRAE 90.1 benchmark and while the toadstool is close to ARCH 2030, the flower has substantially exceeded it! I wonder how much tweaking of the flower’s form it would take to reach net zero.

    • Solar insolation analysis to predict the solar radiation on the surfaces of the forms


The first conceptual form unsurprisingly picks up a huge amount of sunlight with the top of its toadstool-like design. The top section provides substantial shade to the uppermost floors and significant shade to the entire tower beneath it. The south-facing side of the tower receives the most insolation and the northern-facing side receives relatively little by contrast.


The more complicated, flower-shaped design unsurprisingly picks up less sunlight, although more than I expected given the massive decrease in the surface area of its top level. This decrease in insolation has been mitigated by the tower itself being much less shaded by the petals than the simpler design is by its giant circular top.

  • Post images of the design alternatives that you modeled and the results of the analyses

^ toadstool design


^ flower design

(see above sections for analysis)

  • Explain your reasoning and the tradeoffs that influenced your decision about which design option to move forward with

I’ve chosen to move forward with the more complex flower design. I like the simplicity of the toadstool, but the flower is way more fun! The toadstool also shades its tower to such an extent that I think it will require significantly more active heating to maintain a comfortable interior environment. The flower has a friendlier and more open design while still having enough roof surface area to generate significant electricity from PV panels.

While both designs are massive, I feel the toadstool design looks much more imposing and may look almost alien. The flower, on the other hand, looks much more biomimetic to me. I think a future design will need to have the petals curved a bit upwards or downwards so people viewing it from far away won’t see the petals as a single rectangle. I’m also curious to see what modifications would be required to hit net zero, and if the design’s very low EUI will stand up to more detailed analysis.