Thermal energy storage in Swedish single family houses : a case study

In a Nordic climate, space heating (SH) and domestic hot water (DHW) used in buildings constitute a considerable part of the total energy use in the country. For 2010, energy used for SH and DHW amounted to almost 90 TWh in Sweden which corresponds to 60 % of the energy used in the residential and service sector, or almost 24 % of the total final energy use for the country. Storing heat and cold with the use of thermal energy storage (TES) can be one way of increasing the energy efficiency of a building by opening up possibilities for alternative sources of heat or cold through a reduced mismatch between supply and demand. Thermal energy storage without the use of specific control systems are said to be passive and different applications using passive TES have been shown to increase energy efficiency and/or reduce power peaks of systems supplying the heating and cooling needs of buildings, as well as having an effect on the indoor climate. Results are however not consistent between studies and focus tend to be on the reduction of cooling energy or cooling power peaks. In this paper, passive TES introduced through an increased thermal mass in the building envelope to two single family houses with different insulation standard is investigated with building energy simulations. A Nordic climate is used and the focus of this study is both on the reduction of space heating demand and space heating power, as well as on reduction of excess temperatures in residential single family houses without active cooling systems. Care is taken to keep the building envelope characteristics other than the thermal mass equal for all cases so that any observations made can be derived to the change in thermal mass. Results show that increasing the sensible thermal mass in a single family house can reduce the heating demand only slightly (1-4 %) and reduce excess temperatures (temperatures above 24 degrees C) by up to 20 %. Adding a layer of PCM (phase change materials) to the light building construction can give similar reduction in heating demand and excess temperatures, however the phase change temperature is important for the results.

Energy Efficiency through Thermal Energy Storage - Evaluation of the Possibilities for the Swedish Building Stock, Phase 1

As a first step in assessing the potential of thermal energy storage in Swedish buildings, the current situation of the Swedish building stock and different storage methods are discussed in this paper. Overall, many buildings are from the 1960’s or earlier having a relatively high energy demand, creating opportunities for large energy savings. The major means of heating are electricity for detached houses and district heating for multi dwelling houses and premises. Cooling needs are relatively low but steadily increasing, emphasizing the need to consider energy storage for both heat and cold. The thermal mass of a building is important for passive storage of thermal energy but this has not been considered much when constructing buildings in Sweden. Instead, common ways of storing thermal energy in Swedish buildings today is in water storage tanks or in the ground using boreholes, while latent thermal energy storage is still very uncommon.

Electrical conductivity testing of corn seeds as influenced by temperature and period of storage

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Emergence and initial growth of rambutan seedlings as a function of seed storage conditions

Introduction. Rambutan is a tropical fruit species with recalcitrant seeds. Despite the expansion of exotic fruit cultivation in Brazil, lots of which fruit species, including rambutan, need basic information, especially in relation to propagation and storage of seeds, which are important for genetic improvement studies, maintenance of genetic sources and seedling production. Materials and methods. A completely randomized design was adopted with treatments distributed in a factorial arrangement, 3 x 4, referring to three seed storage conditions [room temperature conditions; a dry chamber with (18 +/- 2) degrees C and 60% relative humidity; and a cold chamber with (10 +/- 2) degrees C and 70% relative humidity] and four storage times ( 0, 7, 14 and 21 d). Each treatment of 10 seeds was replicated five times. Data on seedling emergence, emergence rate, plant height, number of leaves and length of main root were submitted to variance analysis and means were separated using Tukey's test. Correlation analysis between seed moisture and seedling emergence was performed. Results and discussion. Our results indicated that dry chamber conditions promoted the statistically significantly highest seedling emergence after 7 d of storage. Cold chamber conditions promoted an extremely low seedling emergence independently of time. Conclusion. Rambutan seeds can be stored in a dry chamber for 7 d without losing viability; after 14 d of storage the loss of emergence is 60%.

Structural changes in soybean seed coat due to harvest time and storage

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of Low-Temperature Storage on Diaeretiella rapae (McIntosh) (Hymenoptera: Braconidae)

We evaluated the effects of constant low-temperature storage on Diaeretiella rapae (McIntosh) (Braconidae, Aphidiinae). Diaeretiella rapae mummies were stored at 5 ± 1°C for 0-36 days. The percentage of D. rapae emergence varied (100-83%) after 0-32 days of storage. After 32 days, emergence reduced to 55%. According to our Probit analysis, 50% mortality (LT50) of the population of D. rapae was reached after 40 days of storage at 5°C. Storage for up to 32 days did not negatively affect emergence and survival. Cold exposure of D. rapae for 36 days did not influence morphological malformations, sex ratio, and emergence of the F1 generation. After 4-36 days of storage, D. rapae showed a gradual decrease in emergence, longevity, reproductive capacity, and F1 sex ratio. Diaeretiella rapae can be stored for up to 24 days at 5°C, at which time the percentage of parasitism and the F1 sex ratio remain above 38% and at 0.50, respectively. © 2013 Sociedade Entomológica do Brasil.

Maturity, Pulp Removal and Storage Effects on the Germination of Livistona rotundifolia Seeds

The Livistona rotundifolia species is native to Oceania, and has a high potential for landscaping use and as a pot plant. This work aimed to study the effects of the maturation stage, pulp removal and storage on the germination of L. rotundifolia seeds. The experimental design was entirely randomized in a factorial arrangement 5x2x2 (five storage periods: 15, 30, 45, 60 and 75 days; two maturation stages: green and ripe; and the presence or absence of the pulp - exocarp and mesocarp) with four replications of 25 seeds each. After sorting out the fruits by the maturity stage and removing the pulp out of half of the fruits from each plot, the seeds were placed in closed bottles, which were sealed and stored in a cold chamber at 10 degrees C. The seeds were removed from the cold chamber and left to germinate in plastic boxes (gerbox type) with sphagnum. The boxes were kept at 25-35 degrees C and photoperiod of 12 hours. The germination rate was determined when seed germination was steady. The highest germination rate was found when green fruits had their pulp removed. The germination rate gradually decreased with the increase of the storage period regardless the maturation stage and the presence or absence of the pulp.

Preparation of cold Mg + ion clouds for sympathetic cooling of highly charged ions at SPECTRAP

Die Elektronen in wasserstoff- und lithium-ähnlichen schweren Ionen sind den extrem starken elektrischen und magnetischen Feldern in der Umgebung des Kerns ausgesetzt. Die Laserspektroskopie der Hyperfeinaufspaltung im Grundzustand des Ions erlaubt daher einen sensitiven Test der Quantenelektrodynamik in starken Feldern insbesondere im magnetischen Sektor. Frühere Messungen an wasserstoffähnlichen Systemen die an einer Elektronenstrahl-Ionenfalle (EBIT) und am Experimentierspeicherring (ESR) der GSI Darmstadt durchgeführt wurden, waren in ihrer Genauigkeit durch zu geringe Statistik, einer starken Dopplerverbreiterung und der großen Unsicherheit in der Ionenenergie limitiert. Das ganze Potential des QED-Tests kann nur dann ausgeschöpft werden, wenn es gelingt sowohl wasserstoff- als auch lithium-ähnliche schwere Ionen mit einer um 2-3 Größenordnung gesteigerten Genauigkeit zu spektroskopieren. Um dies zu erreichen, wird gegenwärtig das neue Penningfallensystem SPECTRAP an der GSI aufgebaut und in Betrieb genommen. Es ist speziell für die Laserspektroskopie an gespeicherten hochgeladenen Ionen optimiert und wird in Zukunft von HITRAP mit nierderenergetischen hochgeladenen Ionen versorgt werden.rnrnSPECTRAP ist eine zylindrische Penningfalle mit axialem Zugang für die Injektion von Ionen und die Einkopplung eines Laserstrahls sowie einem radialen optischen Zugang für die Detektion der Fluoreszenz. Um letzteres zu realisieren ist der supraleitende Magnet als Helmholtz-Spulenpaar ausgelegt. Um die gewünschte Genauigkeit bei der Laserspektroskopie zu erreichen, muss ein effizienter und schneller Kühlprozess für die injizierten hochegeladenen Ionen realisiert werden. Dies kann mittels sympathetischer Kühlung in einer lasergekühlten Wolke leichter Ionen realisiert werden. Im Rahmen dieser Arbeit wurde ein Lasersystem und eine Ionenquelle für die Produktion einer solchen 24Mg+ Ionenwolke aufgebaut und erfolgreich an SPECTRAP in Betrieb genommen. Dazu wurde ein Festkörperlasersystem für die Erzeugung von Licht bei 279.6 nm entworfen und aufgebaut. Es besteht aus einem Faserlaser bei 1118 nm der in zwei aufeinanderfolgenden Frequenzverdopplungsstufen frequenzvervierfacht wird. Die Verdopplerstufen sind als aktiv stabilisierte Resonantoren mit nichtlinearen Kristallen ausgelegt. Das Lasersystem liefert unter optimalen Bedingeungen bis zu 15 mW bei der ultravioletten Wellenlänge und erwies sich während der Teststrahlzeiten an SPECTRAP als ausgesprochen zuverlässig. Desweiteren wurde eine Ionequelle für die gepulste Injektion von Mg+ Ionen in die SPECTRAP Falle entwickelt. Diese basiert auf der Elektronenstoßionisation eines thermischen Mg-Atomstrahls und liefert in der gepulsten Extraktion Ionenbündel mit einer kleinen Impuls- und Energieverteilung. Unter Nutzung des Lasersystems konnten damit an SPECTRAP erstmals Ionenwolken mit bis zu 2600 lasergekühlten Mg Ionen erzeugt werden. Der Nachweis erfolgte sowohl mittels Fluoreszenz als auch mit der FFT-ICR Technik. Aus der Analyse des Fluoreszenz-Linienprofils lässt sich sowohl die Sensitivität auf einzelne gespeicherte Ionen als auch eine erreichte Endtemperatur in der Größenordnung von ≈ 100 mK nach wenigen Sekunden Kühlzeit belegen.

Chemical characterization and quantification of the brown algal storage compound laminarin

In search of a meaningful stress indicator for Fucus vesiculosus we found that the often used quantitative determination procedures for the polysaccharide laminarin (beta-1,3-glucan) result in different kind of problems, uncertainties and limitations. This chemical long-term storage form of carbon enables perennial brown algae in seasonally fluctuating ecosystems to uncouple growth from photosynthesis. Because of this high ecological relevance a reliable and precise method for determination and quantification of laminarin is needed. Therefore, a simple, cold water extraction method coupled to a new quantitative liquid chromatography-mass spectrometrical method (LC-MS) was developed. Laminarin was determined in nine out of twelve brown algal species, and its expected typical molar mass distribution of 2000-7000 Da was confirmed. Furthermore, laminarin consisted of a complex mixture of different chemical forms, since fifteen chemical laminarin species with distinct molecular weights were measured in nine species of brown algae. Laminarin concentrations in the algal tissues ranged from 0.03 to 0.86% dry weight (DW). The direct chemical characterization and quantification of laminarin by LC-MS represents a powerful method to verify the biochemical and ecological importance of laminarin for brown algae. Single individuals of Laminaria hyperborea, L. digitata, Saccharina latissima, F. serratus, F. vesiculosus, F. spiralis, Himanthalia elongata, Cystoseira tamariscifolia, Pelvetia canaliculata, Ascophyllum nodosum, Halidrys siliquosa and Dictyota dichotoma were collected in fall (18.11.2013) during spring low tide from the shore of Finavarra, Co. Clare, west coast of Ireland (53° 09' 25'' N, 09° 06' 58'' W). After sampling, the different algae were immediately transported to the lab, lyophilized and sent to the University of Rostock. Laminarin was extracted with cold ultrapure water from the algal samples. Before extraction they were ground to < 1 mm grain size with an analytical mill (Ika MF 10 Basic). The algal material (approx. 1.5 g DW) was extracted in ultrapure water (8 mL) on a shaker (250 rpm) for 5 h. After the addition of surplus ultrapure water (4 mL) and shaking manually, 1 mL of the sample was filter centrifuged (45 µm) at 14,000 rpm (Hettich Mikro 22 R). The slightly viscous supernatant was free of suspended material and converted into a microvial (300 µL) for further analysis. The extracts were analyzed using liquid chromatography-mass spectrometry (LC-MS) analysis (LTQ Velos Pro ion trap spectrometer with Accela HPLC, Thermo Scientific). Laminarin species were separated on a KinetexTM column (2.6 µm C18, 150 x 3 mm). The mobile phase was 90 % ultrapure water and 10 % acetonitrile, run isocratically at a flow rate of 0.2 mL min-1. MS was working in ESI negative ion mode in a mass range of 100 - 4000 amu. Glucose contents were determined after extraction using high-performance liquid chromatography (HPLC). Extracted samples were analyzed in an HPLC (SmartLine, Knauer GmbH) equipped with a SUPELCOGELTM Ca column (30 x 7,8 mm without preColumn) and RI-detector (S2300 PDA S2800). Water was used as eluent at a flow rate of 0.8 mL min-1 at 75 °C. Glucose was quantified by comparison of the retention time and peak area with standard solutions using ChromGate software. Mannitol was extracted from three subsamples of 10-20 mg powdered alga material (L. hyperborea, L. digitata, S. latissima, F. serratus, F. vesiculosus, F. spiralis, H. elongata, P. canaliculata, A. nodosum, H. siliquosa) and quantified, following the HPLC method described by Karsten et al. (1991). For analyzing carbon and nitrogen contents, dried algal material was ground to powder and three subsamples of 2 mg from each alga thalli were loaded and packed into tin cartridges (6×6×12 mm). The packages were combusted at 950 °C and the absolute contents of C and N were automatically quantified in an elemental analyzer (Elementar Vario EL III, Germany) using acetanilide as standard according to Verardo et al. (1990).

Effects of high temperature and CO2 on intracellular DMSP in the cold-water coral Lophelia pertusa

Significant warming and acidification of the oceans is projected to occur by the end of the century. CO2 vents, areas of upwelling and downwelling, and potential leaks from carbon capture and storage facilities may also cause localised environmental changes, enhancing or depressing the effect of global climate change. Cold-water coral ecosystems are threatened by future changes in carbonate chemistry, yet our knowledge of the response of these corals to high temperature and high CO2 conditions is limited. Dimethylsulphoniopropionate (DMSP), and its breakdown product dimethylsulphide (DMS), are putative antioxidants that may be accumulated by invertebrates via their food or symbionts, although recent research suggests that some invertebrates may also be able to synthesise DMSP. This study provides the first information on the impact of high temperature (12 °C) and high CO2 (817 ppm) on intracellular DMSP in the cold-water coral Lophelia pertusa from the Mingulay Reef Complex, Scotland (56°49' N, 07°23' W), where in situ environmental conditions are meditated by tidally induced downwellings. An increase in intracellular DMSP under high CO2 conditions was observed, whilst water column particulate DMS + DMSP was reduced. In both high temperature treatments, intracellular DMSP was similar to the control treatment, whilst dissolved DMSP + DMS was not significantly different between any of the treatments. These results suggest that L. pertusa accumulates DMSP from the surrounding water column; uptake may be up-regulated under high CO2 conditions, but mediated by high temperature. These results provide new insight into the biotic control of deep-sea biogeochemistry and may impact our understanding of the global sulphur cycle, and the survival of cold-water corals under projected global change.

Fish handling, processing and storage in Uganda: the role of the extension worker

The handling and processing of fish in Uganda has until recently been carried out exclusively by the artisanal fishermen and fish processors. Their operations have left much to be desired as the product is often of low quality 'and its keeping time is limited. The handling of fresh fish has been without refrigeration but with the recent establishment of commercial fish processing plants a cold chain of fish distribution is being set up for domestic and export markets. Some of the fishermen are beginning to ice their catch immediately after reaching the shore. It is hoped that fishmongers will increasingly find it more profitable to market their products iced. This will make fish available to a large sector of the population and in the process there will be reduced post-harvest losses.