Finnish Climatic Conditions Research Articles

Numerical simulation of heat recovery from asphalt pavement in Finnish climate conditions

A 3-dimensional mathematical model of asphalt pavement system was developed, based on the fundamental energy balance, to calculate temperatures beneath asphalt surface using hourly measured solar radiation, air temperature and wind velocity data. The modelling was conducted to predict the heat retention under the asphalt surface to seek an optimum position of pipe tubing to maximise the heat extraction considering the Nordic winter conditions for future infrastructure projects. The model results show good agreement with the experimental results conducted in a span of three months (June–Sept) notwithstanding the simplification of the model i.e. thermal properties unaffected by changing moisture content, perfect contact between different layers and homogeneous and isotropic thermal properties of materials (asphalt, sand and gravel). The findings indicated that the positioning of the heat extraction tubes under the asphalt layer will be dictated by the application. For heat extraction, pipes closer to the surface are ideal for maximal heat absorption during summer, however, in winter the outer temperature may effect properties the pipes. Parameters including pipe diameter, positioning of the pipes and flow rate were analysed. Temperature increase of up to 10°C gain was observed for piping closer to the asphalt layer and 6°C for pipes position at deeper from the asphalt layer. This model could be used in future to optimise critical variables for successful implementation of asphalt heating concepts.

Numerical Simulation of Heat Recovery from Asphalt Pavement in Finnish Climate Conditions

Numerical Simulation of Heat Recovery from Asphalt Pavement in Finnish Climate Conditions

Deacclimation and reacclimation of apple (Malus × domestica Borkh.), blackcurrant (Ribes nigrum L.) and raspberry (Rubus idaeus L.) shoots and buds under controlled conditions

In the future climate scenario the transient warm spells during winter are predicted to become more frequent and potentially increase the risk of frost damage in perennial horticultural crops. The aim of our study was to examine, whether apple (Malus × domestica Borkh.), blackcurrant (Ribes nigrum L.), and raspberry (Rubus idaeus L.) cultivars differing in winter hardiness have a different susceptibility to deacclimation during a warm spell and the ability to reacclimate in response to a subsequent cold period. Shoot samples were collected from commercial orchards in Finland on Feb. 6, 2019. Samples were subjected to a deacclimation treatment (+5°C, 4 d) followed by a reacclimation treatment (-7°C, 7 d). Controlled freezing tests were conducted immediately after sampling, and at the end of deacclimation and reacclimation treatments to determine frost hardiness (FH). FH was most stable in those cultivars that are known to be hardy in the Finnish climate conditions, i.e. ‘Pirja’ apple, ‘Mikael’ and ‘Öjebyn’ blackcurrants, and ‘Maurin Makea’ raspberry. Buds were consistently less hardy than shoots, the difference being largest in blackcurrant, 25°C. The buds of all cultivars, except ‘Pirja’ apple, deacclimated during four days at +5°C, but only ‘Ben Tron’ blackcurrant buds were able to reacclimate. The depth of dormancy was determined by forcing the shoot samples in a greenhouse to examine the relationship of the FH stability to the dormancy status in the cultivars. Sixty to 95 % of apple, 98 to 100 % of blackcurrant, and 55 to 67 % of raspberry buds broke during five weeks in forcing. Only the apple cultivars exhibited cultivar differences in the dormancy status in the beginning of February. ‘Pirja’ despite having the most stable FH of the apple cultivars, showed the most complete and fastest bud break in forcing. Consequently, the susceptibility to deacclimation during a warm spell and the ability to reacclimate at subsequent low temperatures were not related to the status of dormancy in these cultivars.

Low-Temperature Adapted Nitrifying Microbial Communities of Finnish Wastewater Treatment Systems

In this study, the microbial community of nitrifying activated sludge adapted to Finnish climate conditions was studied to clarify the microbial populations involved in low-temperature nitrification. Microbial community analysis of five full-scale wastewater treatment plants (WWTPs) showed several differences compared to WWTPs from other countries with a similar climate. In particular, very low abundance of ammonium oxidizing bacteria (AOBs) (altogether ˂ 0.25% of total community) as well as typical NOBs (˂0.35%) and a high abundance of orders Cytophagales and Micrococcales was observed in all Finnish WWTPs. To shed light on the importance of autotrophic and heterotrophic nitrifying processes, laboratory studies of activated sludge were carried out with a presence of and a lack of organic carbon in wastewater at 10 ± 1 °C. Two different sludge retention times (SRTs) were compared to determine the effect of this operational parameter on low-temperature nitrogen removal. The important role of previously reported Candidatus Nitrotogaarctica for nitrite oxidizing in cold climate conditions was confirmed in both full-scale and laboratory scale results. Additionally, potential participation of Dokdonella sp. and Flexibacter sp. in nitrogen removal at low-temperatures is proposed. Operation at SRT of 100 days demonstrated more stable and efficient nitrogen removal after a sharp temperature decrease compared to 14 days SRT.

Utilizing Asphalt Heat Energy in Finnish Climate Conditions

Geothermal energy is a form of renewable energy, which offers carbon-free solutions for heating and cooling spaces. This study evaluates the use of renewable asphalt heat energy in frozen ground conditions. Asphalt heat energy can be harnessed using a low-energy network, heat collection pipes and heat pumps. This study measured temperatures under the asphalt layer during a three-year period between 2014 and 2017. Measurements were made using a distributed temperature sensing method based on light scattering. Temperatures taken at four different depths under the asphalt (0.5 m, 1.0 m, 3.0 m and 10 m) are presented here. These temperatures are compared with that detected at the depth at which the temperature remains constant all year round. The temperature difference curve between 0.5 m depth and the constant soil temperature depth indicates that from April to October the soil at 0.5 m depth is warming and the temperature difference is positive, even as much as 18 °C. Instead, at the 3.0 m depth, the difference curve is smoother and it varies only from −5 to +5 °C. It is positive from June to November. The surface layer (0 m–1.0 m) is suitable for harvesting heat that can be stored in a deeper (1.5 m–3.0 m) purpose-built storage or in a bedrock heat battery. The calculated heat capacities indicate that asphalt energy, because of high temperatures, is a noteworthy renewable energy source.

Weathering of wood-polypropylene and wood-wollastonite-polypropylene composites containing pigments in Finnish climatic conditions

Purpose – The purpose of this paper is to study the resistance of wood-polypropylene and wood-wollastonite-polypropylene composites containing pigments to natural weathering. Design/methodology/approach – Natural weathering of composites was conducted in Finnish climatic conditions for one year. The colour of the composites was determined with a spectrophotometer, the morphology of the composite surface was analysed by scanning electron microscopy (SEM), and the changes in the polymer structure in surface layer of the composites were analysed with differential scanning calorimetry (DSC). Charpy impact strength was determined with an impact tester. Findings – The pigments used in this study reduced the colour change of the composites exposed to outdoor weathering as compared with the un-coloured composite. The carbon black pigment was more effective than the iron oxide pigment. Moreover, only the carbon black pigment was found to reduce the degradation of the surface layer of the composites. The addition of the carbon black pigment had a positive effect on the dimensional stability of the composites in a water absorption test. Only the combination of the carbon black pigment and wollastonite resulted in a composite which was capable to retain its Charpy impact strength both after one year of outdoor weathering and cyclic treatment. Research limitations/implications – This study is a part of continuous research on the development of wood-polymer composites (WPUs) suitable for outdoor applications in Finnish climatic conditions. The first part of the study, which has been published earlier, showed the results of weathering of composites in accelerated tests in comparison with 1,000 hours outdoor exposure during summer time (June and July). Outdoor weathering limited to 1,000 hours cannot give an objective view on the weathering behaviour of composites in Finnish climatic conditions. The results of the current study were obtained from one-year outdoor exposure of composites. Originality/value – The wood-polypropylene composite made with the combination of the carbon black pigment and wollastonite can be recommended for outdoor applications. The study provides useful information on the resistance of wood-polypropylene composites to weathering in Finnish climatic conditions.

Precision measurement of forest harvesting residue moisture change and dry matter losses by constant weight monitoring

The moisture content of forest-wood chips is one of the most important quality factors for the rapidly growing bioenergy sector. Rising transportation costs and increased use of forest biomass for energy are forcing biomass suppliers towards better moisture-content management in the supply chain. In the literature, numerous studies on natural drying of forest biomass have been conducted based on traditional sampling of piles or weighing. The latest methodology for moisture-change monitoring has been constant weighing of piles in racks built on load cells. In this study, seven piles of logging residues were monitored for between 35 and 85 weeks in Finnish climatic conditions. In addition, two small piles which imitated drying in stand conditions were monitored for 6 weeks. After 8 months of drying, a remarkable dry-matter loss was observed in the logging residue piles.

Possibilities to validate design models for corrosion in carbonated concrete using condition assessment data

This study analyses the actual observed corrosion damage and active corrosion in concrete facades in Nordic outdoor climate and compares this data with the DuraCrete design model for carbonation initiated corrosion propagation phase. Active corrosion was examined in this study by calculating backwards the age of the building and the initiation time by carbonation from a large condition assessment data from concrete facades and balconies using statistical simulation methods. The earliest visible corrosion damage on concrete facades was observed in condition assessments already after 8–15years from construction. In a large group of buildings the damage occurrence was found to reasonably well follow a normal distribution. The design model was found in the case of concrete facades and balconies in Finnish climate conditions to overestimate considerably the propagation phase predictions in all of the studied structure types compared to the statistical analysis. The overestimation in the model is due to the high influence of concrete resistivity and the definition of corrosion penetration needed for the initiation of a crack.

Resistance to weathering of wood-polypropylene and wood-wollastonite-polypropylene composites made with and without carbon black

Purpose – The purpose of this paper is to study natural and accelerated weathering of wood-polypropylene (WF-PP) and wood-wollastonite-polypropylene composites made with and without carbon black. Design/methodology/approach – Natural weathering was conducted in Ruokolahti, Finland in the time of year when solar radiation was maximal. The accelerated weathering tests included exposure to a xenon-arc source with and without spray, and a cyclic test consisting of water immersion–freeze–thaw stages. Findings – Both the type of weathering and the formulation of the composite determined the degree of change in their properties. Weathering, including xenon-arc exposure with spray resulted in much higher changes of colour of non-pigmented composites compared to natural weathering or xenon-arc weathering without spray. Both UV irradiation and moisture had an adverse effect on the Charpy impact strength of non-pigmented composites. Carbon black containing composites performed better than non-pigmented composites. Research limitations/implications – This study is a part of an ongoing research on the development of wood-polymer composites (WPCs) suitable for outdoor applications in Finnish climatic conditions. Outdoor weathering limited to 1,000 h cannot be used for the prediction of the service life of composites and was used here solely for comparative purposes. Originality/value – This paper will help to understand the effect of different weathering factors on the behaviour of WF-PP and wood-wollastonite-polypropylene composites made with and without carbon black (as UV stabiliser). The study demonstrated that while accelerated weathering tests provided useful information on the resistance of WF-PP composites to different weathering factors, they cannot be used alone to predict the behaviour of WPCs meant for outdoor application.

Managed aquifer recharge in community water supply: the Finnish experience and some international comparisons

This paper analyzes the use of managed aquifer recharge (MAR) in community water supply in Finland and presents some international experiences for comparison. The framework of MAR consists of the natural environment and physical infrastructure, as well as socio-economic aspects, all of which are interrelated. Local conditions form the basis of an MAR system and to a large degree determine infiltration options and the most suitable methods. Finnish hydrogeology, climate and local conditions are highly comparable to those in Sweden but differ from those of other parts of Europe, Australia, the USA and Asia. This article provides a holistic view of MAR not only as a technical means of resource enhancement for water supply but also as an element interacting with the natural environment and society.

SUITABILITY OF SWISS HERB CULTIVARS UNDER FINNISH CLIMATIC CONDITIONS

Four newly bred Swiss medicinal and aromatic plant (MAP) cultivars have been tested during 1997-2002 under Finnish climatic conditions: Achillea collina 'Spak', Thymus vulgaris `Varico-1', Alchemilla xanthochlora 'Aper' and Hyssopus officinalis 'Perlay'. The experiments have been carried out in three research stations (South, South-East and North Finland). Most of these cultivars seemed to be suitable for cultivation under Finnish climatic conditions and have produced high quality raw materials. The growth, seed production and overwintering of Achillea collina 'Spak' was good. Its biomass production and essential oil content was at medium level. The biomass production of Thymus vulgaris `Varico-1' was 30% smaller than the 'Deutscher Winter' cultivar, but its essential oil content (4.8%) was 40% higher. As an annual crop, it is suitable for cultivation up to far North, even on the Polar Circle. Compared to local Alchemilla mollis garden accessions, Alchelmilla xanthochlora 'Aper' showed 12-36% higher tannin content (leaves) as well as good overwintering and regeneration after cuttings. On the opposite, Hyssopus officinalis 'Perlay' showed weak growth and overwintering, with lower essential oil content and herb yield than local cultivars. In conclusion, newly bred Swiss cultivars are able to produce good quantities of high quality raw material under the harsh Nordic climatic conditions.

Sorption of Pb(II), Cr(III), Cu(II), As(III) to peat, and utilization of the sorption properties in industrial waste landfill hydraulic barrier layers

The low conductivity landfill barrier layers protect the groundwater and soil by limiting the water flow through the bottom layers of the landfill material. Many materials used in hydraulic barrier layers also have sorption properties which could be used to reduce environmental risks. The adsorption of lead, chromium, copper, and arsenic to peat was studied with a batch-type test and a column test for compacted peat, both without pH adjustment in acidic conditions. Peat adsorbed all the metals well, 40 000 mg/kg of lead, 13 000 mg/kg of chromium, and 8400 mg/kg of copper in the column test. Arsenic was only tested in a batch-type test, and in that peat adsorbed 60 mg/kg of arsenic. The column test showed heavy metals to be adsorbed on the surface layers of the compacted peat sample, on the first centimeter of the sample. The adsorption was much greater in the column test than in the batch-type test, partly due to the different pH conditions and the buffer capacity of the peat in the column test. The liquid/solid ratio of the column experiment represented a time period of approximately 40 years in a landfill, under Finnish climate conditions. The hydraulic conductivity of the peat decreased as it was compressed, but it already met the hydraulic conductivity limits set by European Union legislation for the hydraulic barrier layer (1 × 10 −9 m/s at a pressure of 150 kPa for a 5-m layer), with a pressure of 50 kPa. The results show that peat would be an excellent material to construct compacted, low hydraulic conductivity layers with adsorption properties in, e.g. industrial waste landfills.

Building leakage, infiltration, and energy performance analyses for Finnish detached houses

This study focuses on the relation between the airtightness of a building envelope, infiltration, and energy use of a typical modern Finnish detached house in the cold climate of Finland. The study is conducted with an empirically tested dynamic IDA-ICE simulation model of a detached house. The effect of several factors, such as Finnish climate and wind conditions, balance of ventilation system and leakage distribution, on infiltration was studied and a simple adapted model for the rough estimation of annual infiltration in Finnish detached houses was determined from the numerical simulation results. The energy impact of infiltration is also studied, taking into account the infiltration heat recovery effect. According to the results, infiltration causes about 15–30% of the energy use of space heating including ventilation in the typical Finnish detached house. The average infiltration rate and heat energy use increase almost linearly with the building leakage rate n 50. Finland can be roughly divided into two zones based on the average infiltration rate of detached houses, for which stack-induced infiltration is typically dominant, regardless of the climate zone. The infiltration heat recovery effect is minor in the studied detached house.

Energy crops and renewable energy: overall and process efficiency

Introduction and Objectives The crop scientist focuses his research on high quantity and quality of yield based on a sustainable tilth. The engineer is interested in maximisation of the process efficiency. He interprets the crop scientist’s ap-proach as maximisation of photosynthesis efficiency. Objective of this paper is to support the assessment of energy crop production applying engineering sciences methods in energy accounting. Methods and results The sustainability of energy crop production is assessed by calculating the overall efficiency using rape as example. The results show that the high process energy efficiency of the rapeseed cultivation fosters com-mon acceptance of rape as energy crop. Even under Finnish climate conditions, exergy of rape crop ex-ceeds up to 11-times the energy input for production and exergy of seed up to 3.7 times. Conversion of rapeseed into fuel decreases the energy surplus. Rape methyl ester (RME) delivers still 1.2-fold the energy input for cultivation and conversion. The whole rape crop (root, straw, seed) contains 3 to 6 ‰ of the overall energy input, RME 1 to 2 ‰ only. Animal production converts rape meal feed into manure, which is suitable for anaerobic digestion together with glycerine. The biogas augments the overall efficiency additionally 0.2 to 0.5 ‰. Rape cultivation requires a 4 to 7-year crop rotation. This and the low overall efficiency make it difficult in Finland to achieve energy self-sufficiency replacing diesel fuel by RME. The technical efficiency of the photosynthesis limits the maximum energy yield and reaches up to 0.8 % in Finland. By comparison, the efficiency of a photovoltaic collector is 165 to 248-fold better than the con-version efficiency of biomass or biogas produced from rapeseed and rape straw into electric power. The efficiency of the thermal collector exceeds heat production from burning the rape crop 157 to 443-fold. However, storage and continuous production of power and heat from sun energy is very limited. For that reason, the storage of sun energy in liquid carbon hydrates is subject of present research. Conclusion Energy crop production is captivating with many win-win situations: environmentally neutral bio-fuels replace polluting fossil fuels, farmers get better prices for energy crops, the agrochemical industry gains from intensification of energy crop production, and turn over of power industry grows due to increasing energy consumption to produce agrochemicals and to process biomass into fuel. As a following, the state tax income improves too. However, better prices for mainstream energy crops may trigger export of envi-ronmental pollution at the expense of food production because higher overall efficiency in tropical coun-tries favours the import of organic raw material for bio fuel production. Yet, high process efficiencies of technical processes to convert biomass into fuel justify the production of renewable energy from organic waste and residues. Thus, agriculture should not focus on energy crop production but produce high quality food environment-friendly. The overall efficiency of energy production from energy crops will never be competitive with solar techniques. Solar collectors replace fossil fuels for heat production outside agricul-ture already now sustainable and more efficient. Research on solar-technical processes to produce liquid carbon hydrates from methane, carbon dioxide, and water powered by solar energy without diversion into photosynthesis offers much a greater potential than research on energy crop production. As a measure for sustainability of renewable energy production, the energy surplus from sun energy conversion per capita and square meter is proposed.

Influence of pre partum and post partum plane of nutrition on the performance of crossbred suckler cows and their progeny

The objective of the experiment was to study the effects of two pre partum and four post partum feeding levels on the performance of 28 Hereford-Ayrshire and 30 Limousine-Ayrshire spring-calving mature cows in calf to Limousin and their calves from the beginning of indoor feeding until the end of grazing under Finnish climatic conditions. A 2 H 2 factorial design experiment consisted of a low (L) and moderate (M) pre partum feeding levels based on hay and straw and two post partum concentrate feeding levels, 1.5 and 3.5 kg/d (1 and 2, respectively). The treatments were replicated across the genotypes. For feeding level L the amount of roughage offered was restricted to proportionately 0.7 on a dry matter (DM) basis of feeding level M. Milled barley was offered at 1.3 kg DM/d to all cows 72 days pre calving. The experiment was divided into two parts, an indoor feeding (215 days) and grazing period (114 days). The indoor feeding period included three periods, from start of the study to the beginning of additional concentrate feeding (P1) and feeding additional concentrate supplements both pre (P2) and post calving (P3). On feeding level M cows had a daily intake of 9.1 and 10.4 kg DM during periods P1 and P2, respectively. During period P3 intake was 10.4 and 12.0 kg DM for 1 and 2. Corresponding values for feeding level L were 6.7, 8.0, 8.0 and 9.7 kg DM, respectively. At the onset of grazing, cows on feeding level M were 47 kg heavier (P

The Effect of the Apple Rootstocks YP and A2 on Yield and Winter Hardiness of Apple in Finland

Abstract The most common apple rootstocks in Finland are YP (Yltöinen, Piikkiö) and A2. Their effects on yields and winter hardiness were studied at Häme Research Station in Pälkäne (61°20′N and 24°13′E) near Tampere. The scion varieties grafted on YP yielded better than those grafted on A2 in spite of a lower blooming rate. Both rootstocks had similar vigour and winter hardiness. Their winter hardiness proved acceptable, but both A2 and YP are vigorous and there is a demand for new dwarfing apple rootstock for Finnish climatic conditions.

Testing of a Danish growth model for barley, turnip rape and timothy in Finnish conditions

The biological and meteorological data were collected at Jokioinen in 1982—87. Potential and actual (water limited) production of dry matter were simulated using a Danish WATCROS model for spring barley, spring turnip rape and timothy grass. The most important data of the biological programme comprised weekly measurements of the crop surface (GAI), dry matter yield, root growth, soil water content and yield analyses of the harvest. All these measurements were performed for both irrigated and non-irrigated plots. The needed meteorological parameters for the daily simulation of the dry matter yield were global radiation, air temperature and precipitation. The simulated dry matter production results with the WATCROS model were generally higher than those measured. In order to obtain a better fit into the Finnish climatic and soil conditions, the Finnish model should take soil water conditions and efficient use of photosynthetically active radiation into consideration.

Genetic and management adaptation of field bean (Vicia faba L.) in Finland

The investigation of field bean adaptation in Finnish climatic conditions was carried out at the University of Helsinki in 1976—77. The main objectives were to study the effects of seeding time and population density on the quantity and quality of the yield and the vegetative features in the development of two different types of field bean varieties. Field bean yielded 4061 kg/ha in 1976. In 1977only 2042kg/ha was harvested due to the lack of light during the grain filling period and the presense of plant diseases. Delayed seeding lowered yields in both years. Maximum yield was obtained with the seed rate of 240 kg/ha. Two weeks delay in the seeding speeded up flowering by two days. Temperature sum in degree days from seeding to emergence was 140—170°C, from seeding to flowering 618—637°C and from seeding to maturity 1670—1890°C. LAI was 5.7 for early variety and 4.3 for late variety at the time of pod setting representing very effective situation for CGR. Number and distribution of internodes, pods and seeds were primarily influenced by population density and secondly by the differences between varieties.