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Nord N.,Norwegian University of Science and Technology | Qvistgaard L.H.,Norconsult AS | Cao G.,Norwegian University of Science and Technology
Renewable Energy | Year: 2016

This study examined an integrated solution of the building energy supply system consisting of flat plate solar thermal collectors in combination with a ground-source heat pump and an exhaust air heat pump for the heating and cooling, and production of domestic hot water. The supply energy system was proposed to a 202 m2 single-family demo dwelling (SFD), which is defined by the Norwegian Zero Emission Building standard. The main design parameters were analyzed in order to find the most essential parameters, which could significantly influenced the total energy use. This study found that 85% of the total heating demand of the SFD was covered by renewable energy. The results showed that the solar energy generated by the system could cover 85-92% and 12-70% of the domestic hot water demand in summer and winter respectively. In addition, the solar energy may cover 2.5-100% of the space heating demand. The results showed that the supply air volume, supply air and zone set point temperatures, auxiliary electrical volume, volume of the DHW tank, orientation and tilt angle and the collector area could influenced mostly the total energy use. © 2015 Elsevier Ltd.

Rohde T.,Sintef | Martinez R.,Norconsult AS
Journal of Healthcare Engineering | Year: 2015

This article presents a study of how equipment is used in a Norwegian University hospital and suggests ways to reduce hospital energy consumption. Analysis of energy data from Norway's newest teaching hospital showed that electricity consumption was up to 50 % of the whole-building energy consumption. Much of this is due to the increasing energy intensity of hospital-specific equipment. Measured power and reported usage patterns for equipment in the studied departments show daytime energy intensity of equipment at about 28.5 kBTU/ft2 per year (90 kWh/m2 per year), compared to building code standard value of only 14.9 kBTU/ft2 (47 kWh/m2 per year) for hospitals. This article intends to fill gaps in our understanding of how users and their equipment affect the energy balance in hospitals and suggests ways in which designers and equipment suppliers can help optimize energy performance while maintaining quality in the delivery of health services.

Halling C.,University of Stockholm | Wikstrom S.A.,University of Stockholm | Wikstrom S.A.,AquaBiota Water Research | Lillieskold-Sjoo G.,University of Stockholm | And 3 more authors.
Journal of Applied Phycology | Year: 2013

Seaweed farming has a crucial role in the development of future sustainable mariculture. In the same time, spreading of introduced species or genotypes from farms may threaten local ecosystems. We analyzed a molecular marker (mitochondrial cox2-3 spacers) from cultivated and wild specimen of the widely farmed seaweeds Eucheuma and Kappaphycus, collected in Zanzibar on the African east coast where commercial farming was introduced in 1989. Genotypes of presumed Asian origin were found growing on coral reefs and drifting in seagrass meadows, indicating that genotypes introduced for farming have established successfully in the wild in Zanzibar. Only a very low number of genotypes, all of Asian origin, were found in the farms. This indicates a low accessible gene pool, which can limit the capacity for adaptation to changed conditions and disease resistance in the farming system. African genotypes were found in a few sites, showing the potential for future farming of native strains. The ecological effects of the Asian genotypes introduced to coral reefs should also be further investigated in order to evaluate the risk connected with further introductions of new foreign strains. © 2012 Springer Science+Business Media B.V.

Kjorlaug R.A.,Norconsult AS | Kaynia A.M.,Norwegian University of Science and Technology | Kaynia A.M.,Norwegian Geotechnical Institute
Earthquake Engineering and Structural Dynamics | Year: 2015

The dynamic response of a wind turbine on monopile is studied under horizontal and vertical earthquake excitations. The analyses are carried out using the finite element program SAP2000. The finite element model of the structure is verified against the results of shake table tests, and the earthquake response of the soil model is verified against analytical solutions of the steady-state response of homogeneous strata. The focus of the analyses in this paper is the vertical earthquake response of wind turbines including the soil-structure interaction effects. The analyses are carried out for both a non-homogeneous stratum and a deep soil using the three-step method. In addition, a procedure is implemented which allows one to perform coupled soil-structure interaction analyses by properly tuning the damping in the tower structure. The analyses show amplification of the ground surface acceleration to the top of the tower by a factor of two. These accelerations are capable of causing damage in the turbine and the tower structure, or malfunctioning of the turbine after the earthquake; therefore, vertical earthquake excitation is considered a potential critical loading in design of wind turbines even in low-to-moderate seismic areas. © 2015 John Wiley & Sons, Ltd.

Borgstrom R.,Norwegian University of Life Sciences | Isdahl T.,Norwegian University of Life Sciences | Isdahl T.,Norconsult AS | Svenning M.-A.,Norwegian Institute for Nature Research
Polar Biology | Year: 2015

Although landlocked Arctic charr, Salvelinus alpinus, occur in a large number of High Arctic lakes and often as the only fish species, knowledge of densities and resource use is limited. An allopatric landlocked population of Arctic charr in the 1.47 ha Lake Nordre Borgdam on Svalbard (78°3′N, 13°5′E) was studied during the period 1998–2004. Population abundance was estimated by mark–recapture in July–August 2001. The population was dominated by small individuals with lengths below 16 cm. In 2001, the total number of charr in the length-class 6.0–15.9 cm corresponded to 1,920 individuals/ha or 20.7 kg ha−1. They were mostly feeding on chironomid and trichopteran larvae. The few larger charr seem to feed mainly on smaller conspecifics, and these cannibals probably control the population structure and the abundance of smaller fish. Due to low total number of prey fish in the lake, few individuals are likely to become piscivores. © 2014, Springer-Verlag Berlin Heidelberg.

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