Introduction

Klosterenga is a block of flats in Oslo. The project has implemented several environment-friendly technologies, among them solar collectors from SOLARNOR. The 240 square metres of solar collectors produces about 80.000 kWh per year. SOLARNOR has also provided control systems for under floor heating in each of the 35 flats.
Integrated ecological measures are:
1) Solar collectors for domestic hot water and water-based floor space heating.
2) Double-glazed south facade discussed as part of a passive solar system.
3) Improved insulation standards.
4) Combination of active and passive solar systems.
5) Individually metered apartments (energy consumption).
6) Simplified building details.
7) Reduced number of materials.
Materials that can be recycled or re-used.
9) Materials that can be easily maintained and repaired.
10) Materials that don’t have bad influence on indoor climate.
11) Local cleaning of grey water.
12) Collecting and use of rain water for outdoor purposes and park elements.
13) Building volumes designed to give maximum access to neighbouring park areas.
14) All apartments have visual access to both backyard and park.
15) High and narrow windows to the North improve the amount of daylight.

Objectives and target audience

The target energy consumption is primary energy only (net energy consumption, heat from solar collector not included).

Financial Resources and Partners involved

The project is partly a research and development project to document effects of the different features within the housing co-operative. It is supported by grants from EC through EHEN, the Housing Bank of Norway, the Research Council of Norway, the municipality of Oslo, the Norwegian Water Resources and the Energy Directorate. The cost of the Klosterenga building is 15-20% higher than the reference building at the nearest site. The different features have a payback time of between 5-20 years but the payback period for the active solar heating system, specifically, has been estimated at 15 years.

Process

The building as a whole is formed like a solar collector for the optimisation of active and passive solar energy systems. Rooms that need to maintain a stable temperature are located in the middle, and rooms that are normally kept at lower temperatures are orientated to the north. Rooms for which a variable temperature is acceptable, are orientated to the south.
Measures were taken to:
1)    Minimise energy loss and consumption
2)    Optimise the use of renewable energy
3)    Reduce construction and operating waste
4)    Improve the quality of indoor and outdoor environment.
The annual energy demand for heating of the premises is 195.000 kWh/year, the annual energy demand for heating of tap water is 105.000 kWh/year. The solar collector produces 80.000k Wh/year.
Energy-efficient buildings normally have an annual energy consumption of between 140-180 kWh/m2. Because of the favourable orientation to the south, the aim for Klosterenga was set to 100 kWh/m2.

Results

The energy production and consumption was monitored throughout 2001. Due to problems
with the active solar system, the solar collector was occasionally out of operation.
The active solar system thus produced 270 kWh/m2 in the solar collector area, although the expected output was 300 kWh/m2 per year. The monitoring also revealed differences in expected and actual energy consumption. The aim of 100 kWh/m2 for the heated floor area was met by some of the residents, but the average consumption turned out to be 127 kWh/m2. In 2002, measures like information campaigns towards the residents and installation of new temperature controllers will most likely result in a reduction of the energy consumption.

Critical Success Factors / Challenges

During the three summer months, the solar collector covers the heating demand.