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- Bales, Chris, et al.
(författare)
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TCA Evaluation : Lab Measurements, Modelling and System Simulations
- 2005
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The study reported here is part of a large project for evaluation of the Thermo-Chemical Accumulator (TCA), a technology under development by the Swedish company ClimateWell AB. The studies concentrate on the use of the technology for comfort cooling. This report concentrates on measurements in the laboratory, modelling and system simulation. The TCA is a three-phase absorption heat pump that stores energy in the form of crystallised salt, in this case Lithium Chloride (LiCl) with water being the other substance. The process requires vacuum conditions as with standard absorption chillers using LiBr/water. Measurements were carried out in the laboratories at the Solar Energy Research Center SERC, at Högskolan Dalarna as well as at ClimateWell AB. The measurements at SERC were performed on a prototype version 7:1 and showed that this prototype had several problems resulting in poor and unreliable performance. The main results were that: there was significant corrosion leading to non-condensable gases that in turn caused very poor performance; unwanted crystallisation caused blockages as well as inconsistent behaviour; poor wetting of the heat exchangers resulted in relatively high temperature drops there. A measured thermal COP for cooling of 0.46 was found, which is significantly lower than the theoretical value. These findings resulted in a thorough redesign for the new prototype, called ClimateWell 10 (CW10), which was tested briefly by the authors at ClimateWell. The data collected here was not large, but enough to show that the machine worked consistently with no noticeable vacuum problems. It was also sufficient for identifying the main parameters in a simulation model developed for the TRNSYS simulation environment, but not enough to verify the model properly. This model was shown to be able to simulate the dynamic as well as static performance of the CW10, and was then used in a series of system simulations. A single system model was developed as the basis of the system simulations, consisting of a CW10 machine, 30 m2 flat plate solar collectors with backup boiler and an office with a design cooling load in Stockholm of 50 W/m2, resulting in a 7.5 kW design load for the 150 m2 floor area. Two base cases were defined based on this: one for Stockholm using a dry cooler with design cooling rate of 30 kW; one for Madrid with a cooling tower with design cooling rate of 34 kW. A number of parametric studies were performed based on these two base cases. These showed that the temperature lift is a limiting factor for cooling for higher ambient temperatures and for charging with fixed temperature source such as district heating. The simulated evacuated tube collector performs only marginally better than a good flat plate collector if considering the gross area, the margin being greater for larger solar fractions. For 30 m2 collector a solar faction of 49% and 67% were achieved for the Stockholm and Madrid base cases respectively. The average annual efficiency of the collector in Stockholm (12%) was much lower than that in Madrid (19%). The thermal COP was simulated to be approximately 0.70, but has not been possible to verify with measured data. The annual electrical COP was shown to be very dependent on the cooling load as a large proportion of electrical use is for components that are permanently on. For the cooling loads studied, the annual electrical COP ranged from 2.2 for a 2000 kWh cooling load to 18.0 for a 21000 kWh cooling load. There is however a potential to reduce the electricity consumption in the machine, which would improve these figures significantly. It was shown that a cooling tower is necessary for the Madrid climate, whereas a dry cooler is sufficient for Stockholm although a cooling tower does improve performance. The simulation study was very shallow and has shown a number of areas that are important to study in more depth. One such area is advanced control strategy, which is necessary to mitigate the weakness of the technology (low temperature lift for cooling) and to optimally use its strength (storage).
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- Delbro, Dick, et al.
(författare)
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Nuclear expression of mu-opioid receptors in a human mesothelial cell line
- 2009
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Ingår i: Autonomic & Autacoid Pharmacology. - : Wiley. - 1474-8665 .- 1474-8673. ; 29:4, s. 165-170
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Tidskriftsartikel (refereegranskat)abstract
- 1 Possibly acting via mu-opioid receptors (MORs), morphine inhibits the formation ofexperimentally induced postoperative abdominal adhesions in rats. Mesothelial cells mayparticipate in adhesion formation by secreting mediators that interfere negatively withfibrinolysis. Morphine may prevent adhesions by inhibiting the release of pro-adhesionmediators from mesothelial cells. This study aimed to investigate whether human mesothelialcells express MOR-1; if so, such could constitute a site of action for morphine in adhesionprevention.2 Cells from Met-5A, a human mesothelial cell line were seeded and prepared forimmunocytochemistry and Western blotting.3 Immunocytochemistry showed MOR-1 expression in mesothelial cells, predominantly in thenuclei. Western blotting showed two bands (c. 35 and 50 kDa) which correspond to thoseobtained with a control lysate from cells known to express MORs. In addition, we foundMOR-1 expression with nuclear and cytoplasmatic localization in biopsies from humanabdominal adhesions.4 The current findings may suggest that morphine could interact directly with mesothelial cellsvia MOR-1 receptors, and thereby modulate adhesion formation, possibly by interfering withthe release of pro-adhesion factors from these cells
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| 10. |
- Fiedler, Frank, et al.
(författare)
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Comparison of carbon monoxide emissions and electricity consumption of modulating and non-modulating pellet and solar heating systems
- 2007
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Ingår i: International Journal of Energy Research. - : Hindawi Limited. - 0363-907X .- 1099-114X. ; 31:10, s. 915-930
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Tidskriftsartikel (refereegranskat)abstract
- Emission and electricity consumption are important aspects of a pellet heating system. Low noxious emissions, particularly carbon monoxide, are a measure of a well-performing system. High carbon monoxide emissions are often caused by unnecessary cycling of the burner, poor adjustment of the combustion air and insufficient maintenance. The carbon monoxide output, the thermal performance and the electricity consumption for modulating and non-modulating operation mode have been investigated by simulations of four stoves/boilers as part of combined solar and pellet heating systems. The systems have been modelled with the simulation programme TRNSYS and simulated with the boundary conditions for space heating demand, hot water load and climate data as used in earlier research projects. The results from the simulations show that operating the pellet units with modulating combustion power reduces the number of starts and stops but does not necessarily reduce the carbon monoxide output. Whether the carbon monoxide output can be reduced or not depends very strongly on the reduction of starts and stops and how much the carbon monoxide emissions increase with decreased combustion power, which are in turn dependent on the particular settings of each pellet burner and how the heat is transferred to the building. However, for most systems the modulating operation mode has a positive impact on carbon monoxide emissions. Considering the total auxiliary energy demand, including the electricity demand of the pellet units, the modulating combustion control is advantageous for systems 1 and 4 for the used boundary conditions. The study also shows that an appropriate sizing of the stove or boiler has a huge potential for energy saving and carbon monoxide emission reduction.
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