- your overall HVAC system strategy
- High thermal mass: The concrete floor is designed as some high thermal mass since it can store the heat during the daytime and release the heat during the night. In the targeted building location, most time of the year a heating system is more required according to Climate Consultant. But from the perspective of sustainability, concrete emits a lot of CO2, which can be treated as a tradeoff using concrete floor or slab. My advice is to plant more green areas inside the building to neutralize the effect of concrete.
- Night flushes: It’s reasonable to add some night flushes to the building, such that the windows can be opened during the summer night to lower the inside temperature.
- Natural/fan Ventilation: Opening doors and windows or some other ventilation systems can be added into the building like fans to cool down the temperature. But the tradeoff is by doing this, it’s only available for certain temperatures but picks up more humidity.
- Passive solar direct gain: The key to attaining success in utilizing direct gain passive solar heating lies in the optimal combination of south-facing glass area and thermal mass. Excessive glazing can result in overheating during sunny days; therefore, it is crucial to determine the appropriate amount of glass to be installed. The insulation level of the house also plays a crucial role, as higher insulation standards permit the utilization of a lesser amount of glazing before overheating becomes a concern.
- Wind protection: In Valparaiso, during the winter it’s snowy and windy so it’s necessary to add some wind protection in case of heat loss during the winter.
- Dehumidification: In summer of the city of Valparaiso, storms could happen, so dehumidification equipment may be necessary to make people feel comfortable.
From the Climate Consultant, the climate in the city of Valparaiso is kind of extreme, since for a very limited time people can feel comfortable if only by means of passive design. For the overall strategy, the maximum advantage we could take from the passive design is only about 42%. What’s more, 53.2% of the active design is used for heating and only 5.1% can be used for cooling. For our HVAC system, the main work should be focusing on maximizing the heating efficiency.
- Heating system and strategy
For the active heating system type, I would use air-based ducted heating systems as the transfer medium to distribute heat throughout the building. This type of heating system is typically less expensive to install compared to other options, and it can be integrated with a central air conditioning system. AS mentioned in the overall strategy, using high thermal mass of floors, internal heat gain, as well as passive solar direct gain (glazing walls) will all contribute to the heating passive design.
- Cooling system strategy
From the building envelope aspect, I made a bigger roof to shade the sun during cooling seasons. Also, the green roof which I designed can also absorb some heat to cool down the temperature of the building. For the active design aspect, to be aligned with the heating system, I decided to also use air-based ducted cooling systems. Air-based ducted heating systems use air as the transfer medium to distribute heat throughout the building. This type of heating system is typically less expensive to install compared to other options, and it can be integrated with a central air conditioning system.
Schematic types
The checked parts of the schematic types will be used instead of the conceptual ones to make our result more accurate. In detail, I added some insulation to the floors and roof, glazing windows for walls etc. The setting I used is shown in the picture above. However, this is only a very small part of the HVAC design, we still need to consider the impact of different number of people.
Energy Model
The picture above is the energy model of my building.
It was interesting that the energy report doesn’t show at the beginning. Some adjustments were made by Glenn so I was able to get the maximum heating or cooling loads. The space schedule is shown below.
From the report, we can see “people” is still the critical factor to affect the heating or cooling efficiency, which is about 50%. I’m considering to downsize the people loading to make the building HVAC system more efficient.
1st Level Plan
2nd Level Plan
Overall 3D view
Air handlers
I placed one air handler for each floor to control the HVAC system. The benefit of doing it separately is we can check the system more easily. Also, if one air handler is broken, we can easily locate the broken one. Compare with one central air handler, two air handlers can hold less HVAC loading, so it can be more durable and easier to control. For the size of each air handler, I basically used the same size for each floor. The air handler I used is shown below.
Acc folder link view
Air handler
- Challenge
The design of the duct’s layout and connections of the terminals poses a significant challenge in the design process. The duct elevation is a crucial aspect that requires careful attention to avoid errors and inefficiencies. The presence of a stairwell adds an additional layer of complexity, requiring the ducts to be configured in a manner that accommodates its presence. Connecting the air handler to the ducts requires a diligent approach to avoid potential mistakes. To ensure a successful outcome, a significant amount of time must be dedicated to verifying and checking the design. Despite the effort, finding an optimal solution remains a challenging task due to the intricate nature of the design. As the picture shown below, there are still some alignment problems. It’s also hard to draw connections with changing different views all the time, which is upsetting.
