1. Specifics of multi-apartment building deep complex retrofitting
Anatolijs BORODINECS
Institute of Heat, Gas and Water Technology, Faculty of Civil Engineering, Riga Technical University

2. Objectives
To identify Latvian multi apartment building advantages and disadvantages;
To evaluate energy saving potential;
Study analyses theoretical as well as real measured multi-apartment building heat consumption before and after renovation

4. Latvian multi- apartment buildings
Compactness factor of 9-store multi apartment building building is 0,28.
For 5-storey multi-apartment building with 4 sections compactness factor for such building is 0,35.

5. Average occupancy rate

6. Disadvantages Non insulated building envelope High air leakage rate
Small apartments
Many apartments
High energy consumption, low thermal comfort
Advantages
Homogeneous external wall
Sufficient air exchange rate
High occupancy rate
Efficient building shape

7. 'A business as usual'
Consumption of 6 multi apartment buildings before and after renovation, in City Of Riga

8. Dynamic energy simulation
Retrofitting solution
Existing situation before renovation
According to existing legislation without controlled ventilation
According to existing legislation with mechanical ventilation with heat recovery
Heat consumption for heating, kWh/m2
142,7
53,8
50,4
Heating consumption for Hot water , kWh/m2 56
Lighting, kWh/m2
16,7
Electricity consumption for ventilation, kWh/m2
14,3
Air infiltration of building envelope, 1/h
0,7* including windows opening
0,5* including windows opening
~0.028* windows are closed only mechanical ventilation

9. Nearly Zero Energy Building
Latvian definition for apartment buildings:
Heat consumption for heating – 40kWh/m2;
Primary energy for heating, hot water, mechanical ventilation, lighting and cooling not more than 95kWh/m2;
Heat recovery efficiently >75%;
Use of renewable energy (amount is not clearly defined);
Primary energy factor:
Electricity – 1,5;
District heating
Co-generation
Fossil fuels
0,7
Renewable energy
0,0
Boiler house
1,3
0,1

10. Retrofitting solution
Existing situation before renovation
According to existing legislation without controlled ventilation
According to existing legislation with mechanical ventilation with heat recovery
Heat consumption for heating, kWh/m2
142,7
53,8
50,4
Heating consumption for Hot water , kWh/m2 56
Lighting, kWh/m2
16,7
Electricity consumption for ventilation, kWh/m2
14,3
Primary energy
165
102
123,5
Solar collectors (heat) 285m2 = 29kWh/m2
1m2 – 350kWh per year

11. MORE-CONNECT case building
Typical soviet building;
Silicate brick building;
Widely constructed in suburban and remote areas;
Limited possibilities to apply for EU funds due to building size;
Extra construction costs due to building remote location;
Area – 559 m2;

12. Results
Analysis of energy consumption of already renovated buildings have shown that in a typical situation it is possible to decrease the overall heat consumption by approximately 50% from to kWh/m2; Dynamic calculations performed 5storey multi-apartment building with 4 sections, have shown heat consumption reduction by 62% in case of building thermal insulation according to actual legislation. The installation of fully mechanical supply/exhaust ventilation system resulted in with increase of electricity consumption by 10,8 kWh/m². In should be highlighted that, lack of ventilation system in renovated buildings, resulted unsatisfactory indoor air parameters such increased CO2 concentration and high relative humidity.