Passivhaus - the extremely energy-efficient building standard that has made great inroads in Europe - is commonly associated with homes, however the world’s first Passivhaus public bathhouse and swimming pool just opened this month in Lünen, Germany. The project showcases how even traditionally energy-intensive buildings can conform to the intensive building standard. The project pairs a super-efficient building shell with low-energy equipment, captures waste energy, and offsets energy use with solar electric panels. The 50% energy reduction translates to a whopping projected savings of €193,000 each year.
Photo © DBU
The Lippe Bad Lünen pool is expected to draw 250,000 visitors a year, making the facility a breakthrough project for public green building and saving about a dollar per visitor in energy costs. The bath house was three years in the making, but it’s not completely new — a decommissioned district heating plant built in the sixties was reclaimed to house one of the pools. The original building went through a deep energy retrofit to meet the stringent building standard. The finished bath house has three indoor pools of various sizes and one outdoor pool.
The facility’s walls, roof, and foundation are super tight and highly insulated. The triple-glazed windows help save energy, and they also stay much warmer, which reduces condensation. The building can tolerate much higher humidity levels as a result, which lowers ventilation costs. The ventilation system is based on an energy recovery ventilator or ERV, which extracts the energy in the moist air with incoming fresh air – a mainstay of Passivhaus design. The hot, sauna ventilated air is captured to help heat other parts of the building.
Energy comes from a combined heat and electrical plant or CHP, which runs at around 70% efficiency – double the energy efficiency of a separate boiler and electrical generator. The unit also runs on biogas, and exhaust heat is cycled through a condensing boiler to heat the pool water. A large Photovoltaic system on the roof produces a peak 110 kWs of electricity.
Photos © Ruhrn Achrichten