The passive house application is straight-forward. There is a variety of passive house certified products on the market, including the building materials and ventilation technology. There are good building practise and skilled labour in the building industry.Extremely insulated and air-tight building envelope and good mechanical ventilation system are key elements for any passive house building.
The multi-residential apartments are facing problems with overheating, which leads to occupant dissatisfaction. To provide the thermal comfort to satisfy occupants, the more energy would be needed for running the ventilation system to achieve good indoor climate. With passive cooling with air at nights, one can decrease the annual energy usage. All year-round, the ventilation unit is used for ventilation and when there is an overheating, the unit with correct controls can deliver the cool outdoor air to indoors when the outdoor temperature is, for example, below zero Celsius. This ventilation strategy can bring success if the zone control in the building or apartment is applied with proper HVAC controls strategies.
Zone control for each apartment for passive cooling
Key points for passive cooling:
- Only certain climate zones would support passive cooling.
- Passive cooling can be partially achieved by operable windows, but it might not be desirable in all cases.
- The existence of a mechanical ventilation system is necessary.
- The building is well insulated and airtight. Therefore it has a good balance.
- The orientation of windows must be considered, i.e. south-facing windows can create overheating issues.
- Zone control (for a building and each apartment, i.e. local zone control) and apartment locations can highly influence the results - in used energy, temperature control and delivered comfort.
Several projects in Canada are now in design or under construction to have zone control dampers with passive cooling controls. And more information about passive cooling control at the apartment level can be found in the paper by Hugh Crowther, Erdem Kokgil and Katrina Kostin: Passive Cooling Options for Passive House Multifamily Residential Applications (link here).
Read the conference paper about Passive Cooling Options for Passive House Multifamily Residential Applications
Conference paper by Hugh Crowther, Erdem Kokgil and Katrina Kostin from Proceeding from Passive House Canada Conference, October 2019.
Abstract for the paper. Multifamily residential buildings designed to Passive House are currently the most common commercial application of Passive House. Two key points are the buildings are extremely well insulated and airtight as well as they include a ventilation system. The first point has led buildings to require cooling when the ambient temperature is at or lower than freezing 32°F (0°C). Apartment overheating has led to occupant dissatisfaction. If there is mechanical cooling available, then the call for cooling will address occupant satisfaction but will have a negative impact on annual energy usage and it is hard on the air conditioning equipment (operating air conditioning equipment in cold weather). Having a ventilation system creates the opportunity to use it for passive cooling. This means using the ventilation unit to deliver cool outdoor air to space when outdoor air temperatures permit. This approach has been used on several projects with varying degrees of success. The key issue is zone (apartment) control. Several different controls strategies have been applied with the most promising being local zone ventilation airflow control (passive cooling) as the first stage of cooling.
Download the full conference paper (link here).