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Heat and moisture recovery from the sauna and steam bath also reduced ventilation loss by 50%. "There is also a control system that responds to actual bookings of the wellness modules and only heats them up when necessary," explains Zimmermann. Improved heat insulation ensures that heat losses are only minimal. Eight-metre quadruple glazing, from Glas Troesch, on the building’s north façade insulates the building effectively even in winter. On the roof, solar generation from three photovoltaic systems provides 20,000 kWh of electricity per year. Gym users generate the rest of the electricity themselves, by using the fitness equipment. A solar thermal system produces additional warm water. Finnish sauna, Dübendorf, Zürich
“Our objective is to be able to meet an energyintensive need such as wellness entirely through renewable energy," says Peter Richner, deputy director of EMPA and strategic manager of NEST. NEST is not just aiming to use renewables but also to reduce energy demand. "We want to operate the facility with one sixth of the energy that it would need with conventional operation," adds Mark Zimmermann, innovation manager for NEST.
The underlying energy concept was developed jointly by EMPA researchers, the NTB International University of Applied Sciences and Technology at Buchs, and Lucerne University of Applied Sciences and Arts. "In the Solar Fitness and Wellness Unit, representatives of every link in the value chain work together in partnership on a new sustainable solution – manufacturers of individual components, building technicians, planners, and potential customers," EMPA’s Richner says. CM
The aim is to reduce the 120,000 kWh of electricity that the three saunas – the Finnish sauna, the bio sauna, and the steam bath – would normally swallow up per year to a figure of 20,000 kWh. NEST was able to reduce electricity consumption by using a high-temperature CO 2 heat pump from Swiss refrigeration, heat pump and air-conditioning company Scheco AG, which delivers hot water at temperatures of up to 120°C (for the Finnish sauna) and down to 30°C (for the shower water). The heat pump achieved a coefficient of performance (COP) of approximately three and reduced the Solar Fitness and Wellness Unit’s energy consumption by some two-thirds. “The capacity of our heat pump is 19 kW thermal, 5.7 kW electric,” Zimmermann told Accelerate Europe.
Winter 2017
Accelerate Europe
CO2 heat pump and storage tank