Services Archives - Institute of Numerical Modelling https://modinst.lu.lv/en/pakalpojumi/service/ Scientific Institute of the University of Latvia Fri, 04 Jun 2021 11:04:09 +0000 en-US hourly 1 https://wordpress.org/?v=6.8.3 On-site Building Surveys https://modinst.lu.lv/en/pakalpojums/on-site-building-surveys/ Tue, 06 Apr 2021 16:43:00 +0000 https://modinst.lu.lv/?post_type=portfolio&p=2509 The post On-site Building Surveys appeared first on Institute of Numerical Modelling.

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  • On-site Building Surveys

Description

We perform on-site thermographic surveys and measure various structural characteristics such as air tightness, air change rate, thermal transmittance (U-value) of windows, and other structural elements. We provide gas monitoring and thermal comfort analysis.

We have 20+ years of experience in testing thermal properties of building materials and buildings using both our original and standardized methods and equipment. We have carried out European-scale and local projects such as the ERDF project: Development, optimisation, and sustainability research of smart solutions for near-zero energy buildings in real climate conditions and INPATH-TES: Development of lecture courses on building physics and thermal energy storage materials.

Thermographic Survey

We perform various types of thermographic surveys for buildings, electrical installations, machinery, furnaces etc. according to the LVS EN 13187 and ISO 18436-7 standards, using high-resolution infrared camera FLIR T650sc with high-temperature measurement accuracy, and quality. Camera characteristics: 7.5-13.0 μm spectral range; 640 × 480 px resolution ; noise level NETD < 20 mK; the range of temperature measurements is from -40 °C to 2000 °C with is ± 1 °C, ± 1% precision.

Airtightness of Buildings (q50)

We perform the standardized “Blower door” airtightness (permeability) q50 (m3/m2/h), n50 (m3/m2/h) tests for buildings with airflow up to 42000 m3/h. Measurements are performed using a system of three high-power fans Retrotec 3300 with an additional external air pressure compensator. Maximum airflow generated by the equipment at 50 Pa is 42000 m3/h; flow rate accuracy is ± 3%; maximum door width is 120 cm.

Building Actual Air Change Rate (n, n50)

We perform long-term (multi-week) room air change rate measurements using the tracer gas method. For measurements, we use a gas analyser with a multipoint sampling device INNOVA 1412 i/1303. The measurement is based on injecting a selected tracer/control gas into a room and recording gas concentration over time using the photoacoustic infrared method.

Heat Transfer Coefficient (U)

We perform heat transfer coefficient U [W/(m2K )] measurements for building insulation envelopes in field conditions (during the heating season). We use portable (wired and wireless) measurement systems for local determination of heat transfer coefficient U, also known as the U-value, using – GreenTEG gO with the cellular network connection. We measure with a 1s to 1h frequency. The total duration of measurements is not limited.

We use combined heat-flow/surface-temperature sensors with temperature measurement precision ± 0.1 °C, heat flow measurement precision is ± 3% W/m2, combined humidity and temperature sensors with a measurement precision of ± 0.3 °C and ± 2% for relative humidity.

Heat Transfer Coefficient (Ug) of Glass Panes

We offer fast measurements of the heat transfer coefficient Ug [W/(m2K)] of glass panes. We use Netzsch U-Glass equipment which does not rely on temperature differences, the minimum glass size is: 45 x 45 cm and the heat transfer ratio must be between 0.5 and 4 W/( m2K).

Gas monitoring

We offer long-term monitoring (up to several weeks) of formaldehyde, TOC, CO, CO2, freon concentration on the premises. We use the photoacoustic gas analyser INNOVA 1412 i which utilizes the precise photoacoustic infrared method.

Thermal Comfort

We perform microclimate parameter monitoring, determine thermal comfort rating, and measure the discomfort factor. We perform PMV (Predicted Mean Vote) and PPD (Predicted Percentage of Dissatisfied) index determination according to the ISO7726, ISO7730, ISO7243, ISO7933, ISO11079, and ISO8996 standards.

We use the DeltaOHM HD32 .1 microclimate measuring station and a data processing software which is equipped with the following sensors: bulb temperature; wet-bulb thermometer temperature; ambient temperature; relative humidity; air flowrate; air temperature at different heights; floor surface temperature; radiation intensity and radiation temperature; radiation asymmetry; lighting, CO, and CO2 concentration.

Contact

Andris Jakovičs, Dr. Phys.

Chair of the INM Scientific Council
Head of the Laboratory of Multiphysical Processes
andris.jakovics@lu.lv
0000-0003-3410-5081

Staņislavs Gendelis, Dr. Phys.

Senior Researcher
stanislavs.gendelis@lu.lv
0000-0003-3699-2526
linkedin.com/in/stanislavs-gendelis

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]]> Laboratory Measurements for Building Physics https://modinst.lu.lv/en/pakalpojums/laboratory-measurements-for-building-physics/ Mon, 05 Apr 2021 20:04:00 +0000 https://modinst.lu.lv/?post_type=portfolio&p=2512 The post Laboratory Measurements for Building Physics appeared first on Institute of Numerical Modelling.

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  • Laboratory Measurements for Building Physics

Description

We offer a variety of building physics’ measurements – window, door and multi-layered building material heat transfer coefficients, material thermal conductivity, specific heat capacity, thermal expansion coefficient, and vapour permeability.

We have 20+ years of experience in testing the thermal properties of building materials and buildings using both self-designed and standardized methods and equipment. We have carried out both European-scale and local projects such as the ERDF project: Development, optimisation, and sustainability research of smart solutions for near-zero energy buildings in real climate conditions and INPATH-TES: Development of lecture courses on building physics and thermal energy storage materials.

Window, Door, and Multi-Layered Building Material Heat Transfer Coefficient (U)

We perform window, door and other (multi-layered) building material heat transfer coefficient U [W/(m2K)] measurements according to the EN ISO 899 standards.

We use a calibrated hot box device with the temperature range for both the hot and the cold side from 10 to 40 °C. It has 92 temperature sensors, 56 of these sensors are placed on the sample (32 on the cold side, 24 – the hot one) and the remaining 36 (18 on the cold side, 18 – the hot one) are placed in the surrounding air. The standard measurement window size is 1.23×1.48 m, but samples up to size 1.4×2.1 m can be inserted.

Material Thermal Conductivity (λ)

We determine the heat conductivity λ [W/(m·K)] of both solid and loose materials according to the ASTM C518, ASTM C1784, ISO 8301, DIN EN 12664, DIN EN 12667 standards.

Netzsch 446 Lambda Small can be used to determine the thermal conductivity λ in the 0.007 – 2 W/(m·K) range with 2% precision. The measurement temperature range is from 20 °C to 90 °C. The maximum sample size is 20×20 cm and the maximum thickness is 5 cm.

Taurus TCA 500-P can be used to measure thermal conductivity in the 0.01 – 0.5 W/(m·K) range with 2% precision. The temperature range for the measurements is from 0 °C to 60 °C. The device is intended for relatively large samples from 0×30 cm to 50×50 cm. The maximum sample thickness is 20 cm.

Specific Heat Capacity (cp)

We determine the specific heat capacity cp [J/(g·K)] of both solid and loose materials according to the ASTM C1784 standard. We perform the measurements with Netzsch 446 Lambda small. It can be used to measure the specific heat capacity in the 0.1 – 5 J/(g·K) range with 5-10 % precision. Measurements can be performed in the -20 – 90 °C temperature range. The sample size is 20×23 cm and its thickness – up to 5 cm.

Water Vapour Transmission Rates (sd, μ)

We determine the water vapour transmission rates and other characteristics  (sd, μ etc.) of polymeric films, sheet materials, concrete, stucco, wood, house wrap, woven, nonwoven, and coated textiles, tapes, hygienic, barrier, and medical material using the gravimetric method. We use GraviTest 6400 – 50 mm, where samples can have a maximum height of 5 cm and a surface area of 50 cm2, 6 samples at a time can be placed into the device. The mass resolution is 0.0001g and the measurement time – up to 2 weeks.

Material Thermal Expansion (α)

We measure solid-state linear thermal expansion coefficient α [m/m°C]  using a dilatometer. We use C-Therm DiL, and the temperature range for the device is between 20 and 1600 °C, with a temperature resolution of 0.1 °C. The maximum temperature change rate is 50 °C/min and the maximum sample size change is 4 mm. Samples in the size range of 10 to 50 mm in length and 4 to 22 mm in diameter can be measured.

Contact

Andris Jakovičs, Dr. Phys.

Chair of the INM Scientific Council
Head of the Laboratory of Multiphysical Processes
andris.jakovics@lu.lv
0000-0003-3410-5081

Staņislavs Gendelis, Dr. Phys.

Senior Researcher
stanislavs.gendelis@lu.lv
0000-0003-3699-2526
linkedin.com/in/stanislavs-gendelis

The post Laboratory Measurements for Building Physics appeared first on Institute of Numerical Modelling.

]]> Numerical Modelling https://modinst.lu.lv/en/pakalpojums/numerical-modelling-2/ Sun, 04 Apr 2021 09:58:00 +0000 https://modinst.lu.lv/?post_type=portfolio&p=2526 The post Numerical Modelling appeared first on Institute of Numerical Modelling.

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  • Numerical modelling

Description

Numerical modelling and computer simulations are widely used in industrial research, in the optimisation of various systems and product development. Numerical modelling decreases the necessity for real-life experiments and prototyping, thus accelerating the product development cycle and decreasing the costs. The experts from our Institute create numerical models to describe diverse physical and technical engineering systems and natural phenomena.

Researchers from the Institute of Numerical Modelling have extensive experience in this field –  the University of Latvia has been involved in the field of continuum physics for 50+ years. Our institute has represented this field of research from the very beginning (see History section). We have carried out a variety of both industrial and academic projects in this field.

Heat and Mass Transfer

We perform calculations to analyze heat transfer, humidity transport, and many other properties of different materials used in construction. We can also evaluate the efficiency of different HVAC (Heating, Ventilation and Air Conditioning) systems. We also develop numerical models of conductive, convective and radiative heat as well as humidity transfer for multi-phase (gas/liquid, gas/solute particles, etc.) systems.

Thermal Calculations for Engineering

We develop models of heat and humidity change in the building structural elements, identify and evaluate thermal bridges (equivalent U, ψ) as well as assess the heat balance of a building or a seperate room.

Metallurgy and Magnetohydrodynamics

We develop numerical models describing multi-physical systems where, in addition to thermal and hydrodynamic processes, electromagnetic field evolution must be considered i.e. magnetohydrodynamic systems. The Institute of Numerical modelling has previously developed models for both magnetic stirring furnaces in metallurgy and inductive heating in semiconductor technologies.

System Optimisation

We perform optimisation for a variety of physical and engineering systems, which include electromagnetics, heat transfer, hydrodynamics, solid mechanics, ray optics, and particle transport. We provide models and optimisation algorithms that are suited to the needs and technical requirements of the client.

We use commercial and open-source simulation packages (e.g. COMSOL, ANSYS, OpenFOAM, Elmer) in addition to our own specialized code to translate customers’ goals into mathematical models, perform physical simulations, and optimise systems and processes. We offer parametric, shape, and topological optimization, covering both geometry variations and simple parameters. The finite element method (FEM) is typically used for systems modelling, while for optimization we employ gradient-free algorithms, such as Nelder-Mead, COBYLA, BOBYQA, MMA, SNOPT.

Optical Systems

We perform efficiency analysis for both industrial and home luminaires, analysing their illumination patterns. This includes analysing how well the light covers the given area whether other lighting sources are necessary and if it is possible to improve the shape of reflectors. Both Hamiltonian optics and wave optics are used in the development of our models. Thermal and mechanical effects are included in the calculations as well as the coupling between optical, thermal and mechanical processes.

Contact

Andris Jakovičs, Dr. Phys.

Chair of the INM Scientific Council
Head of the Laboratory of Multiphysical Processes
andris.jakovics@lu.lv
0000-0003-3410-5081

Uldis Bethers, Dr. Phys.

Head of the Laboratory of Environmental Processes
 uldis.bethers@lu.lv
 0000-0002-1596-385X
 linkedin.com/in/uldis-bethers

Jānis Virbulis, Dr. Phys.

Head of the Laboratory of Semiconductor Technologies
 janis.virbulis@lu.lv
 0000-0002-5467-7864
 linkedin.com/in/janis-virbulis

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]]> Consulting https://modinst.lu.lv/en/pakalpojums/consulting/ Sat, 03 Apr 2021 10:38:00 +0000 https://modinst.lu.lv/?post_type=portfolio&p=2558 The post Consulting appeared first on Institute of Numerical Modelling.

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Consulting

Description

The Institute of Numerical Modelling offers consulting services in mathematics, physics, civil engineering,  high-performance computing and numerical modelling. We have 20+ years of experience in developing diverse numerical models and analysing the resulting data. We tailor solutions to the specific needs of a client in terms of optimising manufacturing systems and processes. For instance, we can identify methods for improving the energy efficiency of buildings, among other areas of expertise.

The Institute of Numerical Modelling is a part of the University of Latvia. Our staff is highly qualified (mostly with a PhD or a Master’s degree) and are assisted by energetic science and engineering students. The staff of the Institute of Numerical modelling represents many different fields of science – physics, mathematics, computer sciences, geography, engineering, etc.

Flood Risk Assessment

We offer flood risk assessment for both private and state entities and evaluate areas or building sites specified by the client. We also assess the influence of climate change on the risk of flooding. We use climate data and MIKE suite for developing flood risk recommendations. We have developed the hydrodynamic models of the Daugava and Lielupe river basins.

Climate Change Influence Assessment

We perform a variety of climate data analysis, we evaluate the influence of climate change on transport, power industry, medicine, agriculture sector, etc. Using temperature, precipitation, wind velocity, cloudiness, and relative humidity data, we have developed tools to understand how climate change will influence wind energy, the number of sunny days, phenology, road conditions, visibility, migraines, and the risk of fire hazards.

High-Performance Computing (HPC)

We offer a full high-performance computing (HPC) solution cycle – we select or develop suitable software for each client’s specific needs, we modify it for HPC use, and we supply tools for data visualisation, input, output, and management.

We use self-developed, open-source, and commercial software (e.g. OpenFOAM, Elmer, COMSOL, ANSYS, R Statistics, Python, etc.) run on a 256 core HPC cluster. To supplement our array of HPC service solutions, we have an ongoing partnership with the High-Performance Computing Centre at the Riga Technical University. We also adapt the solutions for use in cloud-based services such as Microsoft Azure, Digital Ocean, AWS, Google Cloud Platform, etc.

Contact

Uldis Bethers, Dr. Phys.

Director of the Institute
Head of the Laboratory of Environmental Processes
 uldis.bethers@lu.lv
 0000-0002-1596-385X
 linkedin.com/in/uldis-bethers

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