Your Design Journal entries for this module should highlight your design thinking and analysis results that influenced your decisions about:
- your overall HVAC system strategy
- your heating strategy and how you implemented it in your design
- your cooling strategy and how you implemented it
- any special HVAC system challenges that you encountered
I considered a VRF to be a highly effective system for this building. It is a building that most of the time will be occupied by a lot of people, whether it is visitors or administrative staff, there will be a lot of energy consumption for the HVAC part. Since it is located in Guayaquil, Ecuador, there is no need for a heating system; it is something that for better or worse, I have never seen and will probably never have the need of it in this city because of its warm weather. Even when the coldest time of the year comes, the walls of a building are more than enough to keep the "cold" temperature out. However, the cooling system will be the one to focus on. With temperatures going from 24 to 33 celsius, and with rising humidity depending on the time of the year, having a good cooling system is key to create a comfortable environment.
With this said, my idea for using a Variable Refrigerant Flow (VRF) system is to maximize efficiency as much as possible. Instead of having a system that uses constant flow with maximum capacity in all of the mechanic equipments, the VRF regulates the refrigerant flow in each of the equipments connected to it based on the specific demand of each one. This prevents the equipments to run at its maximum capacity at all times and still complying with the rooms thermal cooling loads. There are VRF systems with different capacities (BTUs) to manage different equipments. The sum of the capacities of the equipments connected have to be equal or less of the total capacity of the VRF. In my case, I will use fancoils to supply the cold air and distribute it equally in every direction of the different zones. The benefit of the fancoils over a split system for example, is that fancoils has a better air distribution instead of send it in just ine direction; this prevents the rooms to have a colder or a hotter spot because of the air being directed in just that direction.
Since it is a building that will have its air conditioning system on most of the day, it will have to be as much efficient as possible.
The 1st floor is the most challenging for the design of the HVAC system for 2 reasons. It is the floor that has the most different rooms so it will have different zones, meaning that it will need more than 1 fancoil per floor area and more VAVs for these. It is also the floor that has the biggest beams since it carries heavier loads than the upper floors.
I tried using the Climate Consultant but could only get Quito's weather (different city in Ecuador in different region). I did not based my analysis with the results of the software since Quito is located in the highlands, the coldest region of Ecuador, so it would have different criteria. It is a city that do have to consider a heating system.
After merging the models, it could be seen that the HVAC and Structural models intersect in some areas. A possible quick solution could be increasing the ceiling to slab height in each level to give some room for the ducts to pass through.