Renovation of the multi-family building in Cēsis, Kovārņu Street 31 has been launched in the fall of 2010. House was put into operation in 1975, there are 70 apartments with total useful area 4943.7 m2 and heating area 3750 m2.
Energy Audit and Technical Survey proved that the overall technical condition of the building is unsatisfactory as perforated clay brick walls crumble due to increased humidity and low outdoor air temperature, as well as the building exterior wall, attic floor and basement ceiling thermal resistance does not meet the Latvian Building Code requirements.
To avoid the above mentioned problems and improve energy efficiency of the building, the following measures are being implemented within the project:
Insulation of building walls and hydroisolation of basement walls;
Replacement of old wooden-frame windows in apartments;
Insulation of basement ceiling;
Insulation of attic floor;
Renovation of main entrance and backyard doors;
Renovation of heating system and restoration of pipe insulation in the basement;
Renovation of hot water system;
Installation of energy monitoring system;
Glazing of balconies;
Strengthening of major walls and foundations by laying back the crumbled bricks and doing other repair works;
Cleaning of ventilation shafts;
Repairing of staircases.
In result of energy efficiency measures energy consumption in the building is decreased for 53%.
In order to implement the project the Energy Performance Contract among RENESCO Ltd, housing manager and owners of apartments was concluded, providing energy efficiency measures in the building to be implemented, standards of comfort to be respected, as well as commitment of apartment owners and the managing body towards the ESCO company.
Installation of the boiler house
Investment project for installation of a boiler house in a multi-flat building in Cēsis, 31 Kovārņu street, was commenced in the end of 2008. Installation of boiler house was substantially necessary – up to now the building was connected to an old, technically and morally outdated boiler house that was located 200 m away from the residential building; central heating boiler was old, ineffective, with low coefficient of efficiency, moreover it was meant for preparation of considerably larger amount of hot water than the above mentioned building consumes. The number of energy consumers from this boiler house is considerably decreased during the last years, wherewith its maintenance for local government became relatively expensive, moreover the old boiler house and equipment was greatly damaged by fire. According to the heat supply conception of Cēsis city, it was planned to remove this boiler house, however, an agreement was reached that it within limits will operate until launching the new boiler house (building in 31 Kovārņu street).
Equipment of the new boiler room is placed on the ground floor of the building, in its central part. The room is reconstructed and adjusted to the requirements of a boiler house. Chimney is built on the external wall, as well as gas connection and connection to building’s heat supply networks is created.
Equipment is built up of four condensation type Buderus gas central heating boilers which are closed in a cascade connection enabling operation of one or several heating boilers apart from others and dependant on current thermal energy consumption in the building. The power of every separate boiler is 100 kW, the total power if the system – 400 kW or 0,4 MW. Natural gas supplied by the urban gas distribution network is burned in the system. Flue gas from boiler is given off in the atmosphere through a chimney (h=19 m) that is located along the external wall.
Water from urban water-supply is used as heat carrier in heat supply system. Water is used in a closed cycle system without a constant water cumulative flows and it is supplemented only in case of need when the total amount of water in the system is reduced due to vaporization or other losses. The warmed-up heat carrier from the system is delivered to heat exchanger that in its turn provides preparation of hot water and heating for inhabitants’ needs.
The latest technologies are used in the equipment that provides to the utmost effective burning of fuel and retrieval of heat from flue gas. Equipment’s theoretical coefficient of efficiency is 106% and the temperature of diffusive flue gas does not exceed 40 ºC. It enables using of polymer exhaust chimneys, as well as emission of flue gas without elevating emission area if it is permitted by local norms.
System’s total coefficient of efficiency is even more increased by using cascade connection that allows operating every single boiler (or burning system) in optimal regime with the maximum coefficient of efficiency.
Total eligible costs of the project are EUR 285 483, from which part is financed by European Regional Development Fund.