Case Study: Retrofitting of multi-apartment building Sterrenveld

Name of organisation: Gewestelijke maatschappij voor Volkshuisvesting

Stage of development: in progress

Year of finalization: 2007

Type of project: refurbishment

Area: suburban

Scale: neighbourhood

Type of building: Apartment in a block of five or less stories

Number of units/dwellings: 61

Tenure: social rental

Street: Sterrenveld 26

Postcode: 1970

City: Wezembeek-Oppem

Region/ County:

Country: Belgium

Last Update: 29.10.2014

Work with Residents Thermal Insulation Windows and Shading Air Tightness Heating and Hot Water Ventilation Electricity Saving Products Solar Thermal Solar Photovoltaic

Short Description

The project consists in the renovation of the "Sterrenveld" building from 89 to 61 apartments and the transformation of the old central heating plant in a polyvalent space for meeting, social activities and demonstration and offices.
An adjacent old store building is renovated to provide accommodation for the offices of the local social services and for "Kind en Gezin" (institution for social and health support for young children and their family).
It’s a test and demonstration project "best ecological and sustainable renovation practice".

The project was completed in June 2007. The total cost (12.400.000 €) exceeded the ‘standard-cost’ with more than 30%.
The Flemish Government gave a subsidy of 1.199.000 € for the demonstration project.

Key Elements

Thermal Insulation

The building has a global insulation index of K28 (the Flemish standard at the moment of construction was K55, the social housing standard was K45). 10 to 12 cm external insulation was provided for external walls.

Windows and Shading

Uwindow = 1.1W/m².K. (wooden frame and high performance glazing)

Terrasses where added to one side of the building to provide additional space and storeroom sun shading, a ‘winter garden’ and a climate buffer.

Air Tightness

A blower-door-test indicates a air change rate of 3.5 per hour at 50 Pascal.

Heating and Hot Water

Low temperature heating (installed power 320 kW) and hot domestic water (210 kW) are produces separately by condensing boilers. The domestic hot water is preheated by solar collectors (vacuum).

Ventilation

The building has 4 collective balanced air-groups : 2 plate heat exchangers, one heat-pipe and one heat-wheel. The performances of the different systems are to be compared by monitoring.

Solar Thermal

The solar vacuum-pipe collector has a surface of 30m².

There is a water buffer of 3 x 1000 liter. The operating temperature is provided by 2 additional tanks of 300 liter and heater with a condensing boiler. Actually the preheat buffer has been reduced to 1000 liter and the heating buffer to 300 liter to obtain a better performance of the system.

Solar Photovoltaic

There is a small photovoltaic installation of 1.9 KWpeak. The electricity is supplied to the technical installations.

Electricity Saving Products

All fans are equipped with frequency control.

Most of the pumps are equipped with a auto-adapt function.

The energy management system is also controlling the electricity use of the technical equipment.

Work with Residents

Coaching of residents who are motivated by directly involve them in the demonstration aspects of the project. Training sessions and lectures are organised. There is a direct interaction between the building (and energy) manager and the residents.

Main Results

1. Continuous follow-up of energy and water consumption is a must : it resulted in considerable energy and water savings after optimizations of the systems.

2. Monitoring of the thermal and PV solar installations provided a lot of useful and practical knowledge and increased the performances.

3. The knowhow is open to everyone. Seminars can be organised. Student can do research and monitoring.

Lessons learned

1. Renewable energy is an option after very good insulation. Monitoring is a prerequisite to achieve well functioning installations and helps fine-tuning its working conditions.

2. A constant follow-up of the energy and building management system is needed! Otherwise there is no guaranty to obtain the theoretical objectives on energy saving.

3. The heat power is oversized. More appropriated evaluation / calculation methods have to be developed.

4. After some adjustments, the heat recovery units are performing well. Monitoring is still going on.

Source: http://www.powerhouseeurope.eu/nc/cases_resources/case_studies/single_view/?tx_phecasestudies_pi3%5Bid%5D=66&cHash=