A publicly-owned office building in Eskilstuna, Sweden, has been retrofitted with high-frequency with self-regulating controls for the lighting and ventilation systems. The building has a total floor area of 19,000 m2 and contains more than 3 00 offices, a conference room, lunch rooms, and a recreation hall. Before retrofitting the total annual electricity consumption was 1/300 MWh and the district(heat consumption was 950 MWh. The total annual energy consumption was reduced by 20% as a result of the new installlations.
This article describes the retrofitting of a five-family apartment building, implemented as a pilot and demonstration project for the Swiss Federal Office of Energy. The fact that this building on Mutschellenstrasse in Zurich is a listed building, imposes restrictions to the retrofitting process. However, the cellar ceiling, the roof and part of the building facade have been insulated, new windows have been installed and three apartments have been fitted with a mechanical ventilation system with heat recovery. Heating is provided by heat pumps.
The faults during design and installation phases are more critical with cooling systems than with normal HY AC systems: direct evaporated systems in particular require experienced engineers and mechanics. The most common fault is oversizing the systems and the design of the year-round-use system without winter conditions equipment. When the outdoor temperature is cold these systems present problems. The aim of this paper is to present the retrofitting concepts of cooling systems together with improved energy efficiency and operation of the system.