D-BAUG - Departement Bau, Umwelt und Geomatik - ETH Zürich

Key Article ▪ New Monte Rosa Hut SAC
Environmental Sustainability of the Monte-Rosa Hut
The overall concept of a construction process that preserves resources and is free of
pullutants minimizes the impact on our environment and sets new standards in eco-
logical building planning and realisation.
by Stefanie Hellweg, Melanie Goymann, Mathias Wittenwiler / IfU
Goal and scope of the study
Life cycle assessment (LCA) and prospective material and
energy flow balances were used during the planning of the
new Monte Rosa hut.The use of these tools in the early stages
of the planning phase allowed them to have a high leverage
effect on design choices, allowing for sustainable
construction and operation. For example, increased insulation
can reduce heat consumption, and the environmental
impact of energy consumption can be reduced
through the use of renewable energy sources. Construction
materials and processes, including manufacture, transport,
and disposal, were also analyzed. Figure 1 shows the
system boundaries of this analysis. Operation of the hut, including
transport of provisions, was included, although
the production of food and beverages was neglected. It was
assumed that there is no increased demand for nourishment
as a result of visiting the hut.
Methods
An LCA was performed to evaluate the environmental impacts
of the building materials and processes “from cradle
to grave”. Various material choices were assessed, and the
best materials were indicated. For hut operation, electricity
and heat generation, including the production, transport,
and disposal of photovoltaic and lead battery system, and
all other technical devices were considered. Electricity use
of the hut was estimated by extrapolating measured electricity
use data from the old hut. Meteonorm software was
used to calculate solar insolation, and subsequently solar
electricity and heat production. The energy supply system
of the hut will be supplemented with a combined heat and
power plant, which will serve as a back-up system during
bad weather periods. The fuel use of this device was calculated
based on historical weather data, using the difference
between solar energy supply and anticipated demand.
Helicopter flights to transport food and fuel were
40 ▪ D-BAUG Annual Report 2009
included in the study.The life cycle assessment data for the
production of materials and energy were taken from the
database ecoinvent (www.ecoinvent.ch) and additional
project-specific data. Life cycle impact assessment was
performed using two different methods: cumulated energy
demand and global warming potential, calculated over a
100 year timeframe and expressed in CO2 equivalents.
Results
Although the new hut offers more space and a higher level
of comfort, the energy demand and greenhouse gas
emissions per overnight stay are significantly reduced compared
to the old hut (Fig. 2).This decrease in CO2 emissions
comes primarily from the use of renewable energy sources
and building materials, as well as from a well insulated
building, energy-efficient equipment, and by the avoidance
of snow melting through recycling and seasonal storage of
water. Melting and heating water in the old hut led to the
use of 6000 kilograms of coal annually (Fig. 2). The new
wastewater purification plant uses electricity but reduces
the impact of wastewater emissions to the environment.
The use of nontoxic and recyclable materials helps to preserve
resources and to reduce the emission of substances
harmful to the environment and human health. Figure 4
shows the high fraction of renewable energetic resources
used in the production and disposal of the new hut materials.
This is particularly due to the large amounts of wood
used as building material. Almost one third of the total cumulative
energy demand of the construction comes from
the outer wall. The façade is the part of the outer wall
with the highest impact, and the selection of an ecological
façade was therefore very important. Vacuum isolation
panels (VIP), glass with integrated sodium carbonate
hydrate heat storage, and conventional isolation combined
with an aluminium skin were analyzed, and are shown in