Papers by Jarek Kurnitski
Journal of Applied Microbiology, Sep 11, 2018
Aims: The production of peptaibols, toxic secondary metabolites of Trichoderma, in the indoor env... more Aims: The production of peptaibols, toxic secondary metabolites of Trichoderma, in the indoor environment is not well-documented. Here, we investigated the toxicity of peptaibols in the guttation droplets and biomass of Trichoderma strains isolated from problematic buildings. Methods and Results: Seven indoor-isolated strains of T. atroviride, T. trixiae, T. paraviridescens and T. citrinoviride were cultivated on malt extract agar, gypsum boards and paperboards. Their biomass extracts and guttation droplets were highly cytotoxic in resting and motile boar sperm cell assays and in inhibition of somatic cell proliferation assays. The toxins were identified with HPLC/ESI-MS/MS as trichorzianines, trilongins, trichostrigocins and trichostrigocin-like peptaibols. They exhibited toxicity profiles similar to the reference peptaibols alamethicin, trilongins, and trichorzianine TA IIIc purified from T. atroviride H1/226. Particular Trichoderma strains emitted the same peptaibols in both their biomasses and exudate droplets. The trilonginproducing T. citrinoviride SJ40 strain grew at 37°C. Conclusions: To our knowledge, this is the first report of indoor-isolated Trichoderma strains producing toxic peptaibols in their guttation droplets. Significance and Impact of the Study: This report proves that indoor isolates of Trichoderma release peptaibols in their guttation droplets. The presence of toxins in these types of exudates may serve as a mechanism of aerosol formation for nonvolatile toxins in the indoor air.
E3S web of conferences, 2023
Renovation of existing buildings has been highlighted as an essential action in the European Gree... more Renovation of existing buildings has been highlighted as an essential action in the European Green Deal and in the latest revision of the EPBD to achieve energy efficiency targets. Renovation Wave strategy aims to double the deep energy renovation rate in EU by 2030, while specifically targeting the worst-performing segment of the existing building stock. The objective of this study was to assess the energy performance of deep renovation concepts on single and multi-family houses in three different geographical settings -Germany, Italy and Estonia. Typical German 1970s buildings were used as a baseline reference, and it was shown that very similar renovation concepts can be successfully applied across Europe that provides good bases to develop standardized solutions. Energy performance of two common renovation concepts was assessed both with national calculation methodologies and dynamic simulation with harmonized inputs and detailed heat pump plant models. The renovation concepts included improved envelope insulation and airtightness, switched to heat pump systems and heat recovery ventilation as well as incorporated on-site PV while complying with nearly zero-energy requirements for major renovations in all three countries. National energy calculation methodologies showed good accuracy for before the renovation situation but failed in many cases to calculate adequately NZEB renovation concepts with heat pumps and PV, indicating the development needs towards hourly calculation and more detailed treatment of heat pumps.
E3S web of conferences, 2021
The energy efficiency of existing apartment buildings is playing an important role in energy and ... more The energy efficiency of existing apartment buildings is playing an important role in energy and climate targets. In Finland, mechanical exhaust ventilation system is commonly used in older apartment buildings. Hence, there could be an energy saving potential by an exhaust air heat pump system (EAHP). In this work two cases have been studied. Buildings were built in 1960's and 1970's and in renovation equipped with hybrid heating system: district heating and exhaust air heat pump system. Two years measurement data, 2018 and 2019, was collected to evaluate the performance of exhaust air heat pump systems. According to measurement data the monthly coefficient of performance (COP) was calculated as well as seasonal coefficient of performance (SCOP) was defined. The monthly COP values varied from 3,1 to 4,6 and SCOP values were about 3,7. Heating energy cost savings were 23-31 %. Energy performance class before and after EAHP installation was calculated. If at least 50 % of heating energy consumption was covered by EAHP then also energy performance class was improved.
IEEE Access, 2022
Evaluating the energy performance of existing buildings is critical for improving the efficiency ... more Evaluating the energy performance of existing buildings is critical for improving the efficiency and resilience of the building stock as a whole. The importance of this information holds at different scales, both locally and at the national and international levels. A major problem arises from the difficulty in obtaining information from existing buildings; often, the only available data are the yearly consumption per unit area, typically corresponding to the energy performance certificate (EPC). This paper shows how to address concerns of practical relevance with a limited number of variables by examining an EPC national database (including the major cities of Tallinn, Pärnu, Tartu, and others) that provides only EPCs, construction/renovation year and heated area. Through a systematic statistical investigation of nearly 35 000 EPCs of educational, office, commercial and other building typologies, we i) characterise the time evolution of EPC classes, ii) evaluate the impact of incentives pre/post-renovations, and iii) create benchmarking tables that allow comparisons of a specific building with the existing stock to identify representative buildings for detailed auditing. The readiness of the Estonian building stock could thus be evaluated by linear fitting. All new and renovated buildings are estimated to achieve the zero-energy building (ZEB) status by 2050; remarkably, for some categories, this will occur already in the present decade if the identified linear trends persist. Additionally, we investigated whether the COVID-19 pandemic has affected building stock readiness by comparing pre-and post-2020 ZEB year fit estimations. Contrary to what was expected, the change in working habits affected some building types only marginally, while the national regulations played a prominent role. Detached private houses exhibited a pronounced worsening in readiness, while the educational and entertainment sectors benefited from specific energy labelling remodulations.
E3S web of conferences, 2021
Using passive methods in façade design for controlling heating and cooling needs is an important ... more Using passive methods in façade design for controlling heating and cooling needs is an important prerequisite for constructing cost-effective nearly zero-energy buildings. Optimal control of solar heat gains reduces the cooling demand and the size of the active cooling systems. However, applying such methods increases the impact of internal heat gains on the heat balance of the buildings, and accordingly also the dimensions of cooling systems. Therefore, a good model of internal heat gains is needed for a reliable and optimal sizing of the cooling sources. This paper aims to bring understanding to developing internal heat gains models for sizing the cooling systems. For this purpose, several weekly internal heat gain profiles were selected from a large set of tenant-based electricity use measured in 4 office buildings in Tallinn. The selection was based on maximum daily or weekly peak loads of an office space per floor area. The selected profiles and the schedule of EN 16798-1 were used to dimension ideal coolers in the zones of a generic floor model with landscaped offices developed in IDA-ICE 4.8. The model had variable window sizes and thermal mass of the building materials. Finally, the internal heat gains models resulting in the largest cooling capacity were identified. We found that utilizing thermal mass can reduce the cooling system size by up to 7% on average and the models with big windows and light structure need the largest cooling systems. The cooling loads obtained with the profile of EN 16798-1 did not significantly differ from the average of other profiles' results. This paper focused mainly on the zonal dimensioning of cooling systems, therefore a more in-depth analysis of the different occupancy patterns as well as developing models for dimensioning the cooling system at the building level, is needed.
E3S web of conferences, 2019
E3S web of conferences, 2022
-Offices: 20-30 kWh/(m 2 .y) of net primary energy with, typically, 80 -90 kWh/(m 2 .y) of primar... more -Offices: 20-30 kWh/(m 2 .y) of net primary energy with, typically, 80 -90 kWh/(m 2 .y) of primary energy use covered by 60 kWh/(m 2 .y) of on-site renewable sources; -New single family house: 0-15 kWh/m 2 .y) of net primary energy with, typically, 50-65 kWh/(m 2 .y) of primary energy use covered by 50 kWh/(m 2 .y) of on-site renewable sources; Oceanic -Offices: 40-55 kWh/(m 2 .y) of net primary energy with, typically, 85-100 kWh/(m 2 .y) of primary energy use covered by 45 kWh/(m 2 .y) of on-site renewable sources; -New single family house: 15-30 kWh/(m 2 .y) of net primary energy with, typically, 50-65 kWh/(m 2 .y) of primary energy use covered by 35 kWh/(m 2 .y) of on-site renewable sources; and Continental -Offices: 40-55 kWh/(m 2 .y) of net primary energy with, typically, 85-100 kWh/(m 2 .y) of primary energy use covered by 45 kWh/(m 2 .y) of on-site renewable sources; -New single family house: 20-40 kWh/(m 2 .y) of net primary energy with, typically, 50-70 kWh/(m 2 .y) of primary energy use covered by 30 kWh/(m 2 .y) of on-site renewable sources; Nordic -Offices: 55-70 kWh/(m 2 .y) of net primary energy with, typically, 85-100 kWh/(m 2 .y) of primary energy use covered by 30 kWh/(m 2 .y) of on-site renewable sources; -New single family house: 40-65 kWh/(m 2 .y) of net primary energy with, typically, 65-90 kWh/(m 2 .y) of primary energy use covered by 25 kWh/(m 2 .y) of on-site renewable sources. Member States are advised to use renewable energy sources in an integrated design concept to cover the low energy requirements of buildings.
SUMMARY No inhalation toxicity assessment (H314) is currently required of non-volatile substances... more SUMMARY No inhalation toxicity assessment (H314) is currently required of non-volatile substances (European REACH). However, our study shows that non-volatiles can mobilise into humid air. Aerosolisation of potentially hazardous, medium to large molecular-size (300 – 1500 g/mol) substances relevant to indoor air quality were studied in glass test chambers. The test substances, which are classified non-volatile based on their large molecular structure and lack of vapour pressure data, were: 1) toxins of building colonizing moulds, 2) biocidal cationic antimicrobials, and 3) non-ionic tenside and wetting agent polyoxyethylene isotridecanol ether, widely used in building materials and a major constituent of indoor cleaning formulations. Each test substance (0.9 – 30 mg) was dosed on a glass tray, placed on the chamber floor. Humidity was controlled by a humidifier and a dehumidifier and intermittent ventilation. Humidity-driven mobilisation of the non-volatile substances transferred th...
| openaire: EC/H2020/856602/EU//FINEST TWINSThe Nordic countries have taken important and strict ... more | openaire: EC/H2020/856602/EU//FINEST TWINSThe Nordic countries have taken important and strict steps moving towards reducing building energy consumption. Energy performance estimation by dynamic building simulation has become a crucial part of the building design. The performance assessment methodology including pre-determined standardised input parameters vary from country to country. The purpose of this study was to analyse the impact of modelling parameters which are not pre-defined but influence the result, and define specific values to be used in the methodology to reduce the uncertainty and variations in the results. The assessed parameters include the definition of the first day of simulation, e.g. startup date, weekday and calendar year, startup pre-simulation specifics and simulation splitting. The simulations were conducted using dynamic simulation software IDA ICE. Calculations were carried out according to the Estonian national methodology for calculating energy performance of buildings. The study analyses the impact of modelling input data parameters which are not pre-defined in the methodology. The effects of these parameters are illustrated by modelling and simulating multiple typical 5-day usage office buildings. The results show that the startup date can affect the results of the net ventilation heating energy, net ventilation cooling energy or energy performance value over 1 kWh/(m²×a). This study highlights the importance of the initial modelling parameters determination on the building energy consumption calculation results.Peer reviewe
The following interview with REHVA Board Members was conceived as the follow up of a previous Boa... more The following interview with REHVA Board Members was conceived as the follow up of a previous Board members’ interview about nZEB done in the REHVA Journal issue 3/2011. It is intended to be an input for critically facing the first deadline imposed by EU recast for Member States, the definition of intermediate targets toward nZEBs for 2015. We asked three specific questions to the interviewed Board Members: 1) What is still the biggest challenge to reach 20-20-20 target in EU? 2) What is the most important action taken in your country towards nearly Zero Energy Buildings? 3) Which are the most promising HVAC system technologies to give a boost to buildings energy efficiency?
Cost-Effective Energy Efficient Building Retrofitting : Materials, Technologies, Optimization, an... more Cost-Effective Energy Efficient Building Retrofitting : Materials, Technologies, Optimization, and Case Studies
Uploads
Papers by Jarek Kurnitski
hand it is appreciated and requested to make the interiors of
buildings pleasant and comfortable and to save energy for
electric lighting and heating. On the other hand excessive
direct solar exposure can cause occupant discomfort and
harm the energy efficiency of buildings causing overheating
during the warm season. In Estonia, a daylight ordinance
establishes the minimum average Daylight Factor for
residential buildings and an energy efficiency ordinance sets
the maximum acceptable degree hours of overheating. The
two requirements are potentially conflicting. The recent
architectural trend in Estonia is to use very large windows in
residential building design. Even in the Estonian heating
dominated climate this causes overheating issues that lead to
the previously mentioned regulations. This paper explores
the relationship of opening ratios, daylighting and
overheating potential analyzing 7812 design variants taking
into account room, windows and external wall sizes,
presence of shading or balconies and different types of
ventilation. It is shown that the overheating potential can be
contained and both requirements can be satisfied only using
measures such as shading and ventilation.
of classrooms. Poor facade design can result in high indoor temperatures or insufficient access
to natural light. To maintain the required temperatures and illuminance levels in such rooms may
require intensive use of artificial lighting and active cooling systems, which are energy-intensive,
costly to install, operate and maintain. The purpose of this study was to determine essential
parameters and facade design options that ensure overheating prevention and fulfil daylight
requirements in classrooms without mechanical cooling. The present study is based on
simulations of a parametric room model with variable dimensions and orientations. Facade
glazing solutions with optimal combination of solar factor and visible light transmittance were
used to minimize overheating risk and maximize natural lighting impact. For east, south and west
oriented facades, the effect of horizontal shading was also analysed. Overheating assessment
through indoor temperature simulations was conducted with dynamic simulation software IDA
ICE, daylighting was simulated with DIVA4 coupled with Grasshopper software. Results show
that classrooms without mechanical cooling require in depth analysis to determine satisfying
solutions for both overheating and daylighting criteria. The results of this paper can be used for
early stage facade design guide for school buildings or similar use free-running buildings.
Utilization of daylight can significantly help to reduce the need for artificial lighting, increase workers
productivity, customers’ satisfaction and consequently improve sales. However, excessive use of glazing and
absence of lighting controls can contribute greatly to higher energy need for heating and cooling and cause
undesired glare effects. Thus, optimizing the size, position and materials of external glazing, with the addition
of deflectors and dynamic artificial lighting, can become key aspects in the design of sustainable low energy
buildings. The purpose of this paper is to analyze daylight potential and energy performance of a hall-type
commercial building, situated in the cold climate of Finland, by utilizing different combinations of skylights,
windows and lighting controls.
Design/methodology/approach – The authors have used computer simulations to estimate daylight and
energy performance of a single floor commercial building in relation to various combinations of skylights and
windows with variable glazing materials, light deflectors and zonal lighting controls.
Findings – The results show that electric light energy saving potential ranges from a negligible 1.9 percent
to a significant 58.6 percent in the case of glass skylights and wall windows using multi-zone lighting control.
Total delivered energy ranges between increase of 1.5 and 21.2 percent in the cases with single zone lighting
control and between decrease of 4.5 percent and increase of 4.5 percent in the cases with multi-zone control.
The highest decrease in primary energy consumption was 2.2 percent for single zone and 17.6 percent for
multi-zone lighting control. The research underlines the significant potential of electric light energy savings
using daylighting strategies that, including the control of direct solar access for glare and internal gains, can
be more than 50 percent.
Originality/value – This research combines accurate daylight and energy assessment for commercial hall
buildings based in cold climate region with multiple design variations. The novelty of this work is the
consideration of interior elements, shelves and deflectors, in the calculations. This is made possible through
the combined use of validated simulation platforms for detailed annual daylighting and electric lighting
calculation (Radiance and Daysim) and energy analysis (IDA-ICE, Equa Simulation AB). This method allows
to obtain a reliable assessment of the potential of using natural light sources in buildings.
buildings. The European Directive 2010/31/EU states that from 31 December 2020
all new buildings will have to be nearly-Zero Energy Buildings, thus improving
electric lighting energy performance is a key issue. The article presents a study and
energy figures of power density and electric lighting annual consumptions for different
types of buildings, office, commercial and educational, in the northern
European country Estonia with the scope to quantify energy savings when using
different types of high-efficiency luminaires, occupancy and dimming controls,
lighting groups, and daylight contribution. The study has been conducted in relation
to the energy performance regulation for new buildings in Estonia. The scope is to
develop methods for electric lighting and daylight calculations to be used in compliance
assessment with energy requirements. Using different validated software for
electric light and daylight simulations the study analyzes three cases for office
buildings, single office, open office and meeting room, and one case for both commercial
and educational buildings. Results show that average installed power density
can be as low as 3.17 W/m2 for office rooms, 3.22 W/m2 for commercial
buildings and 2.09 W/m2 for classrooms. The reduction of energy consumption
comparing tabulated values can be up 93.3% for office rooms. Also for commercial
and educational buildings energy saving are consistent, up to 72.2% and 87.2%
respectively. The article presents as well electric light and daylight model specifications
and parameters and the different control settings and relative performance.