TY - RPRT
T1 - Investigation on Floating Lid Construction, pit Water Storage, Ottrupgaard, Denmark.
AU - Heller, Alfred
PY - 1997
Y1 - 1997
N2 - At Ottrupgaard a pit water storage of 1,500 m3 and a lid area of
about 700 m2 is built for seasonal storage of a solar collector
field of 560 m2. The lid price is the largest component of a pit
water store with a cost share of about 57%, more precisely 1,163
Dkr./m2. Due to the large share in price the development of lid
constructions is crucial for the development of pit water storage
and seasonal storage, as it seems that the development of solar
collectors will not have a breakthrough in the near future.The
Ottrupgaard lid design is basically a sandwich element
construction of PUR-foam between two metallic covers. The elements
are joint in situ by special steel profiles. A two-step sealing
with silicone mass and bitumen-tape is applied to tighten the
construction.To ensure a proper lid design, two test lids of
1.5x1.5 metres were tested at the Department of Buildings and
Energy under ambient conditions floating on hot water. The test
lids were examined for tightness by a number of means. The results
showed critical construction errors of the first lid design. A
redesigned lid showed acceptable results, but also some water
penetration into the lid insulation. The entered water gathers on
the colder side of the construction where it does no harm. Anyway
the worst case of hot water lying at the bottom of the insulation
is examined by experiments. The experiments proof that the water
will penetrate into the PUR-foam in time. It is not to say from
the experiments if the PUR-foam cells are damaged due to this
penetration. Anyway the heat resistance of the insulation material
decreases with increased presence of water leading to larger heat
losses through the lid, which is undesirable. More work has to be
done on such subjects to understand the effects of hot water on
insulation materials and thereby to ensure proper lid
constructions.In situ examinations of the lid show considerable
heat losses through the lid borders. The concept can and must be
improved to avoid such heat losses.The overall experience is that
the construction is too expensive and complicated but can be
optimized technically as well as economically. The process of
handling, joining the sandwich elements and tightening the
construction is much too demanding and should be changed. The
concept as such is working well if these problems are solved.To
ensure proper lid design and monitoring, measurement methods of
finding moisture and damp in highly insulated constructions plus
conductive heat transport are to be found.Although there is no
applicable lid design after this first project phase, the project
has brought the lid design a step ahead. The project has disclosed
a finite number of ways to go on and find final solutions.
AB - At Ottrupgaard a pit water storage of 1,500 m3 and a lid area of
about 700 m2 is built for seasonal storage of a solar collector
field of 560 m2. The lid price is the largest component of a pit
water store with a cost share of about 57%, more precisely 1,163
Dkr./m2. Due to the large share in price the development of lid
constructions is crucial for the development of pit water storage
and seasonal storage, as it seems that the development of solar
collectors will not have a breakthrough in the near future.The
Ottrupgaard lid design is basically a sandwich element
construction of PUR-foam between two metallic covers. The elements
are joint in situ by special steel profiles. A two-step sealing
with silicone mass and bitumen-tape is applied to tighten the
construction.To ensure a proper lid design, two test lids of
1.5x1.5 metres were tested at the Department of Buildings and
Energy under ambient conditions floating on hot water. The test
lids were examined for tightness by a number of means. The results
showed critical construction errors of the first lid design. A
redesigned lid showed acceptable results, but also some water
penetration into the lid insulation. The entered water gathers on
the colder side of the construction where it does no harm. Anyway
the worst case of hot water lying at the bottom of the insulation
is examined by experiments. The experiments proof that the water
will penetrate into the PUR-foam in time. It is not to say from
the experiments if the PUR-foam cells are damaged due to this
penetration. Anyway the heat resistance of the insulation material
decreases with increased presence of water leading to larger heat
losses through the lid, which is undesirable. More work has to be
done on such subjects to understand the effects of hot water on
insulation materials and thereby to ensure proper lid
constructions.In situ examinations of the lid show considerable
heat losses through the lid borders. The concept can and must be
improved to avoid such heat losses.The overall experience is that
the construction is too expensive and complicated but can be
optimized technically as well as economically. The process of
handling, joining the sandwich elements and tightening the
construction is much too demanding and should be changed. The
concept as such is working well if these problems are solved.To
ensure proper lid design and monitoring, measurement methods of
finding moisture and damp in highly insulated constructions plus
conductive heat transport are to be found.Although there is no
applicable lid design after this first project phase, the project
has brought the lid design a step ahead. The project has disclosed
a finite number of ways to go on and find final solutions.
M3 - Report
SN - 87-7877-009-2
BT - Investigation on Floating Lid Construction, pit Water Storage, Ottrupgaard, Denmark.
PB - Department of Buildings and Energy, Technical University of Denmark
ER -