Driftmodellering av saltvattenbatteri för kapning av effekttoppar

There is a power deficit in Uppsala's power grid. Municipal companies have an obligation to contribute with solutions to the power deficit. Skolfastigheter AB have therefore installed an environmentally friendly salt water battery in one of their properties. The goal of this project is to create an algorithm for controlling the battery so that it cuts power peaks at a preschool in Uppsala. The algorithm is created based on economical, environmental, and political aspects. A model of the battery is constructed in which technical specifications for the real battery are used. The model is tested using historical power usage data from one of Skolfastigheter AB's preschool properties. The resulting model successfully cuts the facility's power peaks as intended. The model succeeds even when the input data are varied. The algorithm is also applied in reality and controls the battery via a programmable logic controller (PLC). The goal of cutting power peaks is also met with the PLC. Simulation of the battery cuts power peaks more optimally than when the algorithm is implemented in reality. To improve the model, data from more preschools as well as possibilities to perform more experiments are required. The usage of programmable power storage is today not economically profitable. Batteries do however contribute to reaching Uppsala municipality's environmental and climate goals. Batteries also contribute to a more robust energy system where fossil power reserves can be avoided

Postural control during quiet standing following cervical muscular fatigue: effects of changes in sensory inputs

The purpose of the present experiment was to investigate the effects of cervical muscular fatigue on postural control during quiet standing under different conditions of reliability and/or availability of somatosensory inputs from the plantar soles and the ankles and visual information. To this aim, 14 young healthy adults were asked to sway as little as possible in three sensory conditions (No vision, No vision-Foam support and Vision) executed in two conditions of No fatigue and Fatigue of the scapula elevator muscles. Centre of foot pressure (CoP) displacements were recorded using a force platform. Results showed that (1) the cervical muscular fatigue yielded increased CoP displacements in the absence of vision, (2) this effect was more accentuated when somatosensation was degraded by standing on a foam surface and (3) the availability of vision allowed the individuals to suppress this destabilising effect. On the whole, these findings not only stress the importance of intact cervical neuromuscular function on postural control during quiet standing, but also suggest a reweigthing of sensory cues in balance control following cervical muscular fatigue by increasing the reliance on the somatosensory inputs from the plantar soles and the ankles and visual information

Altered postural sway in patients suffering from non-specific neck pain and whiplash associated disorder - A systematic review of the literature

To assess differences in center of pressure (COP) measures in patients suffering from non-specific neck pain (NSNP) or whiplash-associated disorder (WAD) compared to healthy controls and any relationship between changes in postural sway and the presence of pain, its intensity, previous pain duration and the perceived level of disability. Summary of Background data: Over the past 20 years, the center of pressure (COP) has been commonly used as an index of postural stability in standing. While several studies investigated COP excursions in neck pain and WAD patients and compared these to healthy individuals, no comprehensive analysis of the reported differences in postural sway pattern exists. Search methods: Six online databases were systematically searched followed by a manual search of the retrieved papers. Selection Criteria: Papers comparing COP measures derived from bipedal static task conditions on a force plate of non-specific neck pain and WAD sufferers to those of healthy controls. Data collection and analysis: Two reviewers independently screened titles and abstracts for relevance. Screening for final inclusion, data extraction and quality assessment were carried out with a third reviewer to reconcile differences

Experimental neck muscle pain impairs standing balance in humans

Impaired postural control has been reported in patients with chronic neck pain of both traumatic and non-traumatic etiologies, but whether painful stimulation of neck muscle per se can affect balance control during quiet standing in humans remains unclear. The purpose of the present experiment was thus to investigate the effect of experimental neck muscle pain on standing balance in young healthy adults. To achieve this goal, 16 male university students were asked to stand upright as still as possible on a force platform with their eyes closed in two conditions of No pain and Pain of the neck muscles elicited by experimental painful electrical stimulation. Postural control and postural performance were assessed by the displacements of the center of foot pressure (CoP) and of the center of mass (CoM), respectively. The results showed increased CoP and CoM displacements variance, range, mean velocity, and mean and median frequencies in the Pain relative to the No pain condition. The present findings emphasize the destabilizing effect of experimental neck muscle pain per se, and more largely stress the importance of intact neck neuromuscular function on standing balance

Fulfill heat demand in houses with district heating and exhaust air heat pump

In Gävle there exists a residential area called Lindbacka where some of the houses are supplied with heat from both district heating and exhaust air heat pump. Gävle Energi owns the district heating system in Gävle and are interested in evaluating the effects from a combined heating system. Based on that, the aim of this study has been to evaluate the impacts a combined system with both district heating and heat pump can have compared to if only one of the two is installed in a house. The thesis has studied these perspectives in an energy, environmental and economic analysis. The results from the energy analysis display that the heat losses in the district heating system relative to the amount of heat sold to customers are relatively large during the year, especially in the summer when the losses are larger than sold amount of energy. The results from the environmental analysis indicates that heat pumps have a larger climate impact during operation measured in tons of carbon dioxide equivalents compared to district heating. On the other hand, the economic analysis present heat pumps to be the cheapest heating option for a customer. The most expensive option for a customer is to install both an exhaust air heat pump and connect to the district heating system since this leads to double fixed and variable costs during the year. For Gävle Energi the economic analysis indicates that the investment cost of building the district heating system to Lindbacka was not profitable since the investment cost does not pay back in 30 years. Some of the houses in Lindbacka has been excluded in the thesis due to insufficient data. This will have an impact on the results in the thesis

Fulfill heat demand in houses with district heating and exhaust air heat pump

In Gävle there exists a residential area called Lindbacka where some of the houses are supplied with heat from both district heating and exhaust air heat pump. Gävle Energi owns the district heating system in Gävle and are interested in evaluating the effects from a combined heating system. Based on that, the aim of this study has been to evaluate the impacts a combined system with both district heating and heat pump can have compared to if only one of the two is installed in a house. The thesis has studied these perspectives in an energy, environmental and economic analysis. The results from the energy analysis display that the heat losses in the district heating system relative to the amount of heat sold to customers are relatively large during the year, especially in the summer when the losses are larger than sold amount of energy. The results from the environmental analysis indicates that heat pumps have a larger climate impact during operation measured in tons of carbon dioxide equivalents compared to district heating. On the other hand, the economic analysis present heat pumps to be the cheapest heating option for a customer. The most expensive option for a customer is to install both an exhaust air heat pump and connect to the district heating system since this leads to double fixed and variable costs during the year. For Gävle Energi the economic analysis indicates that the investment cost of building the district heating system to Lindbacka was not profitable since the investment cost does not pay back in 30 years. Some of the houses in Lindbacka has been excluded in the thesis due to insufficient data. This will have an impact on the results in the thesis