In 2020, Umeå region aims at being world leading in sustainable building in cold climate. This and the EPBD were driving factors for the City of Umeå for developing a lighthouse project in building the northernmost certfied passive house. It will also be BREEAM-certified, a unique combination so far in Sweden. The project is developed together with the municipal operator to suit for their Reggio Emilia inspired education.
The use of ecological, nonpoisonous building materials is decisive as well as long-living building and easy to change appliances. It is about ressource-efficiency and the target is to create a building with a negative CO2-banlance in a 50-year-lifecycle. 4 options of building design have been tested with LCC method, resulting in a concept which will meet the following criteria:
- Specific space heating demand ≤ 15 kWh/(m2,a)
- Total specific primary energy demand ≤ 120 kWh/(m²a)
- -87% reduction of heating demand and -80% of total energy demand compared to building code
- Airtightness Pressure test result, n50≤ 0.3 h‾¹ or 0,15 l/(sec, m²)
Hedlunda preschool is situated on a municipal lot, distance to the city centre about 1km. The new building is replacing a old one, thereby not leading to additional soil sealing. The area is well connected and easily accessible by sustainable transport modes (cycling, public transport).
The process started with a 2-step architect comptetion in 2011, in which one part was about planning a passive house. No more environmental targets and goals have been set in the competition. The winning Sweco-concept included already the use of renewable nonpoisonous building materials, meeting sustainable certification criteria and a zero-energy-concept. The concept has been optimized in a step-by-step process together with the responsible municipal departments which resulted in a decision to go for a flagship project and the use well-known international certification systems.
All energy calculations have been done with the Passive House Planning Package (PHPP) which is the key design tool used when planning a Passive House and as such, serves as the basis of verification for the Passive House Standard.
Standardized calculation of economic efficiency:
4 different building from standard building code going to the most ambitious passive house design have been calculated with LCC method, while using the following basic parameter:
- Price district heating: 0,5 kr/kWh
- Price electricity: 0,8 kr/kWh
- Increase energy price per year 5%
- Interest rate 4%
- Timeline 50 år
The calculation showed that the international passive house design had the lowest lifecycle costs.
Some technical details:
Kind of public use: All-day kindergarden and daycare center for the age of 1-7 years.
Total effective area: BBR (Swedish system to count the area) 1580 m2, PHI (for the Passive House certificate) 1323 m2
Number of levels above earth: 2 levels preschool, 1 level restaurant and kitchen.
Source of energy for heating: District heating with renewable fuel, with only use of returning district heat water.
Type of heating system: Under floor heating system.
Type of water heating system: Energy from the district heating system (returning water) and from the energy recovery of the food cooling- and freezing units of the restaurant and kitchen.
Type of ventilation system: Passive House certified central ventilation systems with heat recovery system and an effective heat recovery rate of 86%.
Exhausted air from the kitchen will be cleaned with Ozone to reduce cooking odours and grease before the heat recovery is possible in a normal ventilation unit.
All building material is documented in a digital register incl. type, name, producer, content, delivery note and where used. Beyond, a complementing list of which materials are not allowed has been developed and is in use.
Planning support for energetic optimization
All energy calculations have been done with the Passive House Planning Package (PHPP).
There is a space allocation plan for the project (which also is used as tabulation for all building materials).
Part of PHPP is to take into account of all internal heat gains, passive solar gains, thermal bridges and more.
Part of the planning process was to develop an air tightness concept with detailed drawings and material recommendations. There is also a training of construction workers as the airtight layer may be practiced. In any case will we have two Blower Door tests together with infrared thermography.
Information for users:
Under the whole planning process meetings every two weeks meetings were held with the project-, building- and the kindergarten management. All of them have been involved in the process, the concept, the floor plans, the function of the building and the selection of materials and equipment.
A large display in the entrance area will shows the current and the average annual energy consumption. An alarm bell will sounds in the school kitchen when the present power consumption of the kitchen appliances exceeds the calculated power consumption.
Contact and further information:
Projectmanagement Umeå kommun: Christer Svärling, Christer.Svarling@umea.se
Thomas Greindl, Sweco Architects Umeå, firstname.lastname@example.org