- Site exploration:
There are a number of reasons for which I’d like to use one of the proposed sites, the Jasper Ridge Biological Preserve, as the setting for this project. In my last design journal entry, I had set the ambitious target of wanting to reach net zero site energy for my building design, and the Bay Area, with its moderate climate and relatively mild heating and cooling demands, facilitates this achievement. In addition, I wanted to design a building with very targeted views, and Jasper Ridge provides a gorgeous backdrop against which to set such a design (sample image below).
On Google Earth, a simple 2D bird’s eye view of the site looks like the following:
While the site is quite rural and isolated from dense human populations, there are some preexisting buildings to contend with while positioning my intervention. There are, of course, natural features as well that should also be thoughtfully considered in the design of the building. For instance, there is a lake nearby which may provide a spectacular view from a window of the building; however, there are also significant wooded areas nearby which obstruct this view (and may also pose a challenge for positioning PV panels so that they stay unshaded). The image below shows the first person street view from the red dot above, facing towards the lake — and as you can tell, the trees are mostly blocking the view to the lake. As such, it may be productive to consider designing a building which has some verticality to it, so that a broader view of the preserve can be seen from the upper floors.
The topography at the site seems to be quite variable, with some steeper gradation going down to the lake, but generally the area which may be more favorable for setting this design project (because of relative positioning to the wooded areas and lake) also seems to have much more gentle changes in slope. There is an existing field station there as well (as shown on the right below).
- Site climate
Again, as previously stated, this site is located in the Bay, where winters are barely cool and summers are temperate as well. The solar resource here seems decent, and hopefully a PV system will be able to provide the energy necessary for a fully electrified heating and cooling system. As we can see, the average temperatures year round hover not too far out from the comfort zone.
The psychrometric chart generated by Climate Consultant 6.0 for the zip 94062 (San Mateo) is shown below with the Consultant’s recommended design strategies highlighted.
As is evident (and as previously conjectured), active cooling is required very little of the time; much of the required thermal comfort can be achieved sufficiently through passive strategies, including direct gain, strategic shading, and thermal mass storage. Heating demands are slightly higher, but active heating is only required for about 1/3 of the time. This environment seems quite conducive to an energy efficient design.
- Conceptual massing
The conceptual mass modeling that I did is still pretty blocky, and the two forms I’ve shown here are pretty different. They both explore a couple of the different concepts I took inspiration from. This first one tries to establish different zones for different activities — i.e. the towers that rise above the shared platform base are programmatically separate. This is inspired by that TED video we watched about the residence in Singapore, and also by the Lewis Center for the Arts at Princeton University, where I spent a lot of time in undergrad.
This next idea incorporates some of what I mentioned in my inspiration posts from earlier this quarter — inspired by the Louisiana MoMA in Copenhagen, I wanted to have an exhibit with an obvious path of movement through it and that had several buildings surrounding green space(s). This is shown above, with different buildings (maybe also programmatically separate) surrounding a common courtyard. The different sizes and shapes of the masses surrounding the courtyard can maybe provide for a dynamic experience moving through the exhibit.
- Solar and energy analysis
I think for this mass model, I may have oversized the elements (you can see the surface area selected is pretty large, perhaps a bit larger than is needed) and I somehow could not figure out how to simultaneously scale everything down at once (so please ignore that for now!). The solar analysis shows a good amount of insolation, with almost all the roof elements receiving on average almost 1500 kWh/m2. It seems that for this building, there is no clear direction of orientation, and orienting the building in different directions didn’t seem to greatly influence the amount of insolation the roof received. Nonetheless, the one shown above is where the long axis of the form is oriented perpendicular to the N-S axis. Some highlights from the Insight analysis are shown below.
Above are some of the strategies that were most effective at decreasing the annual energy cost. Originally, the building did not even meet the ASHRAE 90.1 standards, but increasing the PV surface coverage to around 60% and increasing the plug load efficiency to above average helped decrease the cost from $15 USD/m2yr to around $10 USD/m2yr.
For this building, there seemed to be a slightly higher amount of solar resource available — I conjecture that this is partly because there is a definite orientation to the building. Inspired by the existing field station on site, which has roofs tipped towards the south for PV insolation, this building has south-facing sloping roofs on its two major masses to take advantage of solar resource. Some highlights from the Insight analysis are shown below.
I adjusted some of the ranges to represent the energy efficiency strategies I plan on implementing, and to my surprise, it took the cost per year from around $12/m2yr to less than zero. The major adjustments I made are shown above — I increased window shading on the south and west walls; this would help reduce solar heat gains in the summer (on the south) and late in the day (on the west). I moved the range of PV surface coverage to around 50%, which greatly reduced the annual energy cost — I’m not sure if this percentage is achievable, but we’re still in the early stages of design here and it’s good to know! In addition, increasing the PV payback period to 20+ years greatly reduced the annual cost of energy. I think if I were to choose one of these two designs, I’d most likely move forward with this second one, as it has a lot more dynamic elements I can play with, and I think it would be a bit easier to implement energy efficient tactics on this building mass.