Solar heated DesiCool saves up to 60% Energy

The unveiling of Energy Fyn’s newly constructed office premises in Denmark is one of the world's first ventilation systems that uses solar panels to power Munters DesiCool system which cools and ventilates an office building.  

Courtesy of Nicolai Østergaard, Ingenioeren, Denmark

By using solar heated water, the energy consumption for cooling and ventilating Energi Fyn’s new head office will be reduced by upto 60% compared to the energy consumption for conventional ventilation systems. At the same time, the power to run the system will be supplied by solar cells.

“We wish to demonstrate how natural it is to use solar panels to provide energy for the ventilation for a large office building. On hot summer days, when the need for ventilation is at its greatest, solar panels can deliver plenty of hot water for the cooling process,” says Henrik Vorgaard, CEO of Energi Fyn. The cooling process uses the heated water to dehumidify the incoming air and again during the evaporation process in the DesiCool system, which is used to bring the air to the correct temperature before it is sent back inside the building.  

Traditional ventilation systems for industrial sites and office buildings have always been relatively harmful to the environment. This is partly due to the large amounts of cooling agent, usually 200 litres or more, which was stored in the installation’s tanks and which could leak out into the atmosphere, and partly due to the high level of energy consumption required to run the installation’s compressors and cooling surfaces. Munters DesiCool ventilation system located in the newly constructed premises performs the dessicant cooling utilising the solar panel system as soon as it produces water with a temperature of 55˚C or above.

 “In practice, this means that the cooling installation will be able to run on solar power all year round, since our tests over the past weeks have shown that even on overcast and relatively cool days, the solar panels still supply water with a temperature of more than 60°C,” says Project Manager Robert Blach from Munters, which supplied the DesiCool installation.

The installation can also draw on energy from the local district heating network if required. The installation’s cooling effect is about 240 kW and can process an air volume of 46,000 m³/h. During the winter, the installation has a heat recycling rate of 90 %. The installation contains neither compressors, cooling surfaces nor condensers with ventilators.  

The solar panel installation covers 37.5 m² and delivers a yield of 520 kWh/m² per annum. The panels are the only solar panels in the world that are able to provide a temperature which can reach 110°C and still maintain a high rate of efficiency. The solar panels were supplied by Arcon.

“Technological development means that solar energy can now supply energy to a cooling installation all year round, because it only needs 55°C to supply energy to the process. Cooling and solar power therefore, have now developed into a perfect match,” says Rene Rubak, Arcon’s technical expert.

He emphasised that the solar panels are constructed using a special, anti-   reflective glass with a surface that acts like a large number of prisms. This means that even if the sun is in a position of 50 degrees away from direct radiation on the solar panels, such as in the early morning, the surface will still absorb 94% of the sun's rays. “So in real terms, normal daylight is all that is required to obtain the required effect. Solar radiation of just 300 watts is enough to produce a water temperature of over 55°C,” says Rene Rubak.

180 employees will spend their working day in the new premises over two floors with a large, open plan office. The building cobers 7,000 m² in total and the solar power installation  and DesiCool sytem will be complemented by intelligent light systems that will adjust the light intensity relative to the light entering the windows.