SKOV A S

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Rong L.,University of Aarhus | Pedersen P.,Skov A S | Jensen T.L.,Skov A S | Morsing S.,Skov A S | Zhang G.,University of Aarhus
Biosystems Engineering | Year: 2017

Evaporative cooling pad are widely used in poultry production houses in hot and arid climate to provide an appropriate indoor thermal conditions for animals. Currently, the main challenge of this system is to maintain the indoor thermal conditions stable so that the productivity is ensured. This study used wind tunnel measurements to investigate the dynamic performance of evaporative cooling pad under different control strategies including altering water supply duration which was defined as pump-on time (ranging from 3 s to 120 s) and control time cycle (3, 4 and 5 min), which was defined as the sum of pump-on and pump-off time in a cycle. A cross-fluted design of impregnated cellulose pad with dimensions of 1.8 m × 0.6 m × 0.15 m (height × length × thickness) was used and constant water flowrate of 7.5 l min−1 is applied. The results indicated that periodic pattern of temperature and cooling efficiency was observed due to the setting of pump-on time. Larger variation in air temperature difference between inlet and outlet of evaporative cooling pad occurred when the control time cycle was longer and face air speed was bigger. Supplying water to the pad caused higher resistance to the air travelling through the pad. A relationship was presented between cooling efficiency and a ratio defined by pump-on time, water flow rate, control time cycle and air flow rate. The ratio of water to air can be implemented by the controller. © 2017 IAgrE


Grant
Agency: European Commission | Branch: FP7 | Program: JTI-CP-ARTEMIS | Phase: SP1-JTI-ARTEMIS-2009-1 | Award Amount: 24.36M | Year: 2010

The proposed RECOMP (Reduced certification cost for trusted multi-core platforms) research project will establish methods, tools and platforms for enabling cost-efficient certification and re-certification of safety-critical systems and mixed-criticality systems, i.e. systems containing safety-critical and non-safety-critical components. RECOMP recognizes the fact that the increasing processing power of embedded systems is mainly provided by increasing the number of processing cores. The increased numbers of cores is commonly regarded as a design challenge in the safety-critical area, as there are no established approaches to achieve certification. At the same time there is an increased need for flexibility in the products in the safety-critical market. This need for flexibility puts new requirements on the customization and the upgradability of both the non-safety and safety-critical critical part. The difficulty with this is the large cost in both effort and money of the re-certification of the modified software, which means that companies cannot fully leverage the advantages of modular software system. RECOMP will provide reference designs and platform architectures together with the required design methods and tools for achieving cost-effective certification and re-certification of mixed-criticality, component based, multi-core systems. The aim of RECOMP is to define a European standard reference technology for mixed-criticality multi-core systems supported by the European tool vendors participating in RECOMP. The RECOMP project will bring clear benefits in terms of cross-domain implementations of mixed-criticality systems in all domains addressed by project participants: automotive systems, aerospace systems, industrial control systems, lifts and transportation systems. RECOMP will thus provide solutions that will allow European industry to increase its market share in the growing market of mixed-criticality systems.


Liu D.,University of Aarhus | Guldberg L.B.,SKOV A S | Feilberg A.,University of Aarhus
Chemical Engineering Transactions | Year: 2014

Odour emission from intensive pig production is a major source of local nuisance and sulphur-containing odorants (e.g. hydrogen sulphide and methanethiol) have been recognized as key odorants. Biological air filter has emerged as a cost-effective technique to remove odorants from ventilation air. However, low removal efficiencies for sulphurous odorants have been observed when a large volume of air has been applied with low concentrations. Recent kinetic studies on full scale biological air filters indicate that the removal of odorants is related both to mass load and air load of odorants but the dependence of sulphurous odorants on loading rates are not clear due to the very low and highly varying removal efficiencies. In the present study, two inoculated biofilter columns were applied to test the dependence of sulphurous odorants (hydrogen sulphide, methanethiol and dimethylsulfide) removal on air loading rate, mass loading rate or concentration. Specially designed commercially available ceramic saddles and cellulose pads were selected as biofilter media for the experimental tests. Whereas the air loading rate varied from around 10 to 1300 m3m-3h-1, the mass loading rate varied from approximately 10 to 500 mg m-3 h-1 for hydrogen sulphide. Concentration levels varied from around 10 to 3000 ppbv for hydrogen sulphide, covering the typical concentration range of H2S emitted from pig facilities. The results indicated that the removal of hydrogen sulphide and methanethiol was closely dependent on air loading rate for both biofilter columns. Whereas the removal of hydrogen sulphide was observed to be also dependent on mass loading rate and concentration for the ceramic saddles packed biofilter column, the removal efficiency of H2S was independent on mass loading rate or concentration for cellulose packed biofilter column. Further, significant competition between methanethiol and hydrogen sulphide was observed for the ceramic packed biofilter column, when the mass load of hydrogen sulphide was increased. On the other hand, no such competition was observed for the cellulose packed column. Kinetics analysis indicated that both Grau second-order kinetics and Stover-Kincannon model can generally be applied to describe the degradation of both hydrogen sulphide and methanethiol in biofilters, except a small deviation observed for methanethiol, when applied to Stover-Kincannon model. Copyright © 2014, AIDIC Servizi S.r.l.


Hansen M.J.,University of Aarhus | Liu D.,University of Aarhus | Guldberg L.B.,SKOV A S | Feilberg A.,University of Aarhus
Journal of Agricultural and Food Chemistry | Year: 2012

There is an urgent need to develop odor reduction technologies for animal production facilities, and this requires a reliable measurement technique for estimating the removal of odorants. The purpose of the present experiment was to investigate the application of proton-transfer-reaction mass spectrometry (PTR-MS) for continuous measurements at a biofilter from SKOV A/S installed at a pig production facility. PTR-MS was able to handle the harsh conditions with high humidity and dust load in a biofilter and provide reliable data for the removal of odorants, including the highly odorous sulfur compounds. The biofilter removed 80-99% of carboxylic acids, aldehydes, ketones, phenols, and indoles and ca. 75% of hydrogen sulfide. However, only ∼0-15% of methanethiol and dimethyl sulfide was removed. In conclusion, PTR-MS is a promising tool that can be used to improve the development of biological air cleaning and other odor reduction technologies toward significant odorants. © 2012 American Chemical Society.


Liu D.,University of Aarhus | Hansen M.J.,University of Aarhus | Guldberg L.B.,SKOV A S | Feilberg A.,University of Aarhus
Environmental Science and Technology | Year: 2012

Biofiltration is a cost-effective technology for removing air contaminants from animal facilities. Kinetic analysis can be helpful in understanding and designing the process but has not been performed on full-scale filters treating complex mixtures. In this study, kinetics was investigated in a full-scale biological filter treating air pollutants from a pig facility. Due to the high air flow rates used in the filter, both a plug flow model and a model based on complete mixing were tested with respect to kinetic order and Michaelis-Menten kinetics. Application of these models only gave poor to moderate agreement with air filter removal data. Two alternative kinetic models (Stover-Kincannon model and Grau second-order model) adopted from wastewater biofiltration process analysis were introduced to analyze contaminant removal in the biological air filter. Data analysis demonstrated the applicability of these two models with a high degree of precision on contaminant removal in the biological air filter. Whereas the Stover-Kincannon model demonstrated that pollutant removal rates were related to the mass loading rates, the Grau second-order kinetic model indicated that the removal efficiencies were dependent on air loading rates. Therefore, the kinetic data can be used for comparing biofilter performances and for design purposes. © 2012 American Chemical Society.


Ottosen L.D.M.,University of Aarhus | Juhler S.,University of Aarhus | Guldberg L.B.,SKOV A S | Feilberg A.,University of Aarhus | And 2 more authors.
Chemical Engineering Journal | Year: 2011

The objective of the present study was to study mechanisms controlling substrate consumption and growth of ammonia-oxidizing bacteria (AOB) in a NH3 loaded agricultural biotrickling air filter. A series of filter NH3 load manipulations was performed. HNO2 was observed to constitute around half of the AOB oxidation products, and assumed the main inhibitor of AOB growth and substrate consumption. Under operating conditions with stable NH3 load, biomass increased until self-inhibition restricted further growth. Sudden load changes affected pH and the level of free HNO2, and caused an immediate (within few hours) change in substrate consumption rate. At persisting load change (over a period of weeks) the biomass adapted to a new level dictated by the new average NH3 load. It is suggested that the theoretical minimum outlet NH3 concentration is controlled by the filter water concentrations of NH4 + and Σ(NO2 -+NO3 -), which due to conservation of charge balance is found in an approximately 1:1 ratio. Heterotrophic oxidation of odorous compounds appeared to be unaffected by short-term changes in AOB inhibition levels. © 2010 Elsevier B.V.


Hansen M.J.,SKOV A S | Feilberg A.,University of Aarhus | Adamsen A.P.S.,University of Aarhus
Chemical Engineering Transactions | Year: 2010

The aim of the present experiment was to investigate the stability of volatile reduced sulphur compounds during dilution in an olfactometer. Two types of olfactometers were used. In the first olfactometer the parts in contact with the samples were made by glass and in the second olfactometer stainless steel and PTFE (polytetrafluoroethylene, Teflon). The olfactometers were tested with a sulphur gas mixture containing hydrogen sulphide, methanethiol and dimethyl sulphide at ca. 5 ppmv. A PTR-MS (Proton-Transfer-Reaction Mass Spectrometer) was used to follow the fate of sulphur compounds in the olfactometers. The samples were diluted as normal samples for olfactometry, and the PTR-MS was used to measure the concentration in the nose mask, where panellists normally assess the diluted samples. The concentration in the samples was analysed prior to dilution in the olfactometers and the expected concentration in the nose mask was estimated using the dilution factor. The concentration measured in the nose mask as a function of the estimated concentration was linear for both olfactometers. This shows that dilution of the samples was working properly. In both olfactometers a part of the sulphur compounds were lost during dilution and the degree of loss correlated with the volatility of the sulphur compounds. The average loss of hydrogen sulphide was 60% for the glass olfactometer and 55% for the olfactometer with stainless steel and PTFE. The average loss of methanethiol was 35% in the olfactometer with glass and 27% in the olfactometer with stainless steel and PTFE. Dimethyl sulphide was only slightly affected by the dilution system in the olfactometer with glass with an average loss at 9.3%, whereas 21% was lost in the olfactometer with stainless steel and PTFE. It can be concluded that panellists assessing samples with reactive volatile reduced sulphur compound in these two types of olfactometers will underestimate the original concentrations. Copyright © 2010 AIDIC Servizi S.r.l.


Jonassen K.E.N.,Pig Research Center | Pedersen P.,SKOV A S | Riis A.L.,Pig Research Center | Soorensen K.,Pig Research Center
Chemical Engineering Transactions | Year: 2012

In 2010 during a test of a biological air cleaner 16 samples in triplicates were collected before and after the air cleaner over 8 weeks and analysed within 30 hours at two Danish laboratories and one German laboratory. There was a significant difference between the results from the three laboratories. The mean values of odour concentration from the laboratory with the highest results were up to 27 times higher than those from the laboratory with the lowest results (n = 16). Besides the discrepancy between the results from the laboratories, the odour removal efficiency of the air cleaner varied from 16 % to 80 %, indicating that the result of the test of the air cleaner largely depends on the choice of laboratory. One of the main groups of odorants from pig production is the volatile organic compounds containing sulphur, especially hydrogen sulphide and methanethiol, which are considered to be some of the most important and potent odorants. Hydrogen sulphide was always measured when odour samples were collected. Analytical results from one of the Danish laboratories and the German laboratory obtained in 2011 showed that hydrogen sulphide contributes to odour concentration to a different degree in the two laboratories. Both laboratories comply with CEN EN 13725:2003 (CEN EN 13725, 2003) standard and use the same kind of olfactometer. Copyright © 2012, AIDIC Servizi S.r.l.


Trademark
Skov A S | Date: 2015-07-15

Alarm sensors; An optical metrology inspection system comprised of a light source, one or more cameras and sensors in communication with computer software and hardware; Day and night vision systems primarily comprising day and night sensors, day and night cameras, power sources, communication means, monitors and operating software; Electric or electronic sensors for climate and feed handling; Electric sensors; Electric, electronic, or electrochemical oxygen monitors and sensors for environmental use; Electronic proximity sensors and switches; Gas sensors for measuring gas concentration; Humidity sensor with integrated digital and analog output circuitry used in automotive, appliance and light industrial applications to sense both relative humidity and temperature environmental conditions; Light systems comprising light sensors and switches; Liquid level sensors; Optical sensors; Proximity sensors; Sensors for determining position, velocity, acceleration and temperature; Sensors for the determination of temperatures, positions and distances.


Trademark
Skov A S | Date: 2015-07-15

Alarm sensors; An optical metrology inspection system comprised of a light source, one or more cameras and sensors in communication with computer software and hardware; Day and night vision systems primarily comprising day and night sensors, day and night cameras, power sources, communication means, monitors and operating software; Electric or electronic sensors for climate and feed handling; Electric sensors; Electric, electronic, or electrochemical oxygen monitors and sensors for environmental use; Electronic data relays for sensors; Electronic proximity sensors and switches; Environmental monitoring system comprised of meters and sensors that measure pressure, humidity, temperature and includes alarm and reporting functions; Gas sensors for measuring gas concentration; Humidity sensor with integrated digital and analog output circuitry used in automotive, appliance and light industrial applications to sense both relative humidity and temperature environmental conditions; Light systems comprising light sensors and switches; Liquid level sensors; Optical sensors; Sensors for determining position, velocity, acceleration and temperature; Sensors for the determination of temperatures, positions and distances; Temperature sensors.

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