Tag Archives: measurement

xxx P. Kic
Electric infrared heating panels as an alternative source of heating for greenhouses
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Electric infrared heating panels as an alternative source of heating for greenhouses

P. Kic

Czech University of Life Sciences Prague, Faculty of Engineering, Department of Technological Equipment of Buildings, Kamycka 129, CZ165 21 Praha 6, Czech Republic
Correspondence: kic@tf.czu.cz

Abstract:

The aim of this article is to show the possibilities of supplementary heating of greenhouses. There was used for this research an electric infrared heating panel ITA 700. The average total power was 630.8 W in laboratory measurements, of which 504.3 W has been transferred by the front part of the panel, of which 267.2 W has been transmitted by radiation. The total radiation efficiency of the front part was 42.4%. Similar measurements have been carried out in an experimental greenhouse (length 24 m, width 3.5 m). Approximately 448 W of average total power 603.7 W has been transferred by the front part of the panel, of which 159 W has been transferred by radiation. The total radiation efficiency of the front part was 26.3%. Differences between measured surface temperatures confirmed the influence of panel radiation on the flower bed. The average temperature in the soil (9 °C) shows that the influence of heating is mainly on the surface of the flower bed, where it could protect cultivated plants during the lowest temperature period. The obtained results can be useful for choosing suitable panel parameters for the placement in small horticultural or hobby greenhouse.

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945–956 D.V. Cao and P. Kic
An analysis of influences of blinds and solar radiation on microclimate in office rooms during summer days: a pilot study
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An analysis of influences of blinds and solar radiation on microclimate in office rooms during summer days: a pilot study

D.V. Cao* and P. Kic

Czech University of Life Sciences Prague, Faculty of Engineering, Department of Technological Equipment of Buildings, Kamýcká 129, CZ165 21, Czech Republic
*Correspondence: caodoan2006@gmail.com

Abstract:

Windows are the only part of a building that can directly penetrate the solar radiation into the occupied space and thus the shading devices are needed to control the solar penetration. In the office buildings, they usually use external blinds and internal blinds to reduce heat gains during summer caused by sunlight as well as solar radiation. Therefore, these blinds are main part to maintain thermal comfort for office workers. The aim of this paper is to present results of measurements in four big office rooms in different situations of blinds application. Then, the influence of the internal and external blinds on the internal microclimate conditions inside the large offices during the hot summer days with high solar radiation will be evaluate. The offices floor area is from 43.3 m2 to 59.5 m2 and height 2.8 m. The experiments in this research were focused on measurement and evaluation of globe temperature, indoor air temperature and relative humidity at level of working place during several hot summer days. Comparison of the results of short-term measurements in a room with open blinds and closed blinds has shown the influence of the blinds on the reduction of indoor temperature. More significant was the effect of external aluminium blinds. Solar energies passing through the windows into the interior were 3,476 W without blind and 305 W in case of aluminium venetian external blinds. When the maximum outside temperature was 29.9 °C and office workers used blinds with natural ventilation, the maximum air temperatures in four rooms were from 27.2 °C to 28.5 °C, which exceeded maximum recommended temperature (28 °C). The external aluminium venetian blinds and internal fabric vertical blinds did not maintain thermal comfort inside the offices during all summer days, but it can help in reduction of energy consumption for air-conditioning.

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438–446 J. Hart and V. Hartová
Measurements of wireless detectors used to monitor animal movements in livestock farms
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Measurements of wireless detectors used to monitor animal movements in livestock farms

J. Hart¹* and V. Hartová²

¹Czech University of Life Sciences Prague, Faculty of Engineering, Department of Technological Equipment of Buildings, Kamýcká 129, CZ165 00 Prague, Czech Republic
²Czech University of Life Sciences Prague, Faculty of Engineering, Department of Vehicles and Ground Transport, Kamýcká 129, CZ165 00 Prague, Czech Republic
*Correspondence: janhart77@gmail.com

Abstract:

At present, there is a great interest in monitoring and automating farm animals and livestock farming. There are many systems and methods to check the movement of animals in certain areas. One option is to use motion detectors. However, some installations are so specific that they require the use of wireless motion detectors. They not only have to fulfill their functional part but also have a sufficiently strong signal that should not interfere outside the defined ISM bands. Due to the frequent deployment of different types of these detectors, research has been carried out to monitor shortcomings in frequently used types of wireless detectors. This research defines which tested detectors are fully usable according to the standards and which need to be modified by the manufacturer. Also, based on measurements, the basic risks and recommendations for the use of individual types of tested detectors are defined.

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1235–1245 M. Topol, P. Kic and P. Neuberger
Reduction of moisture and thermal conductivity of wet walls by special plaster
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Reduction of moisture and thermal conductivity of wet walls by special plaster

M. Topol¹*, P. Kic¹ and P. Neuberger²

¹Czech University of Life Sciences Prague, Faculty of Engineering, Department of Technological Equipment of Buildings, Kamýcká 129, CZ165 21 Prague, Czech Republic
²Czech University of Life Sciences Prague, Faculty of Engineering, Department of Mechanical Engineering, Kamýcká 129, CZ165 21 Prague, Czech Republic
*Correspondence: TopolMilan@seznam.cz

Abstract:

This paper is focused on the problems of moisture reduction in old buildings. Wet walls are very common problem of old buildings, but it can appears also in new buildings as well. The moisture in the wall influence the insulation quality; bigger heat losses continuously cause problems of worse heat balance, higher consumption of energy for heating and it can result in not sufficient indoor conditions in such a room or building. Old rural residential buildings and also agricultural buildings for housing of animals, storage of different materials, workshops etc. could be repaired and reconstructed by the used of some special methods. The application of special plaster can reduce the walls moisture as well as improve the thermal properties of the buildings by reduction of thermal conductivity. This paper includes the results of laboratory experiments focused on research of plaster properties (temperature, moisture and thermal conductivity) and tests provided in the real building. Different measuring principles, enabling mutual comparison of results were used for this research. The measurement results showed a significant effect of high wall moisture on the heat losses. Differences between the walls improved by new tested plaster and old untreated walls are discussed in this paper. Obtained results from this measurements and findings may be useful for further research in this issue as well as for the practical solutions for similar problems in many old buildings.

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1771-1780 E. Merisalu, D. Mugur and P. Kic
Importance of microclimate conditions and CO2 control in educational buildings: a case study
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Importance of microclimate conditions and CO2 control in educational buildings: a case study

E. Merisalu¹*, D. Mugur¹ and P. Kic²

¹Estonian University of Life Sciences Tartu, Institute of Technology, Fr. R. Kreutzwaldi 56/1, EE51006 Tartu, Estonia
²Czech University of Life Sciences Prague, Faculty of Engineering, Department of Technological Equipment of Buildings, Kamýcká 129, CZ165 21 Prague, Czech Republic
*Correspondence: eda.merisalu@emu.ee

Abstract:

Current efforts to minimize energy losses and maximize energy savings for heating of all houses are most often gained by insulating facades and replacing windows. However, these measures can have a significant negative impact on human health and these problems can occur in buildings with a high concentration of people, such as school buildings. The aim of this paper is to analyse the results of measurements of air temperature, relative air humidity and carbon dioxide in winter period in the classrooms of two universities, Estonian University of Life Sciences (EULS) in Tartu and Czech University of Life Sciences (CULS) in Prague. The measurements have carried out in 2017-2018 in eight classrooms of the EULS and two classrooms of the CULS. The external and internal temperature, relative humidity and concentration of carbon dioxide have measured in the classrooms during a few days in the winter period. In the lecture rooms of CULS, when the air conditioning was off, the levels of CO2 exceeded the recommended levels about two times. The average internal temperature and CO2 concentrations in the classrooms of EULS follows the norms and refers on good ventilation. The extremely low relative humidity in the classrooms of EULS at 17.1 ± 2.6% refers to a high risk of allostatic load and respiratory symptoms among students. It is important to pay attention on regular ventilation and relative air humidity control in the teaching rooms, especially with high number of students to prevent seasonal sickness of upper respiratory tract.

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1077-1084 P. Kic and P. Neuberger
Thermal properties of historic rural building materials in Czechia
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Thermal properties of historic rural building materials in Czechia

P. Kic¹* and P. Neuberger²

¹Czech University of Life Sciences Prague, Faculty of Engineering, Department of Technological Equipment of Buildings, Kamýcká 129, CZ165 21 Prague, Czech Republic
²Czech University of Life Sciences Prague, Faculty of Engineering, Department of Mechanical Engineering, Kamýcká 129, CZ165 21 Prague, Czech Republic
*Correspondence: kic@tf.czu.cz

Abstract:

Due to the different natural conditions, various local natural building materials were used for the construction of rural residential and farm buildings in various locations in the Czech Republic. Currently, it is often a requirement for the modernization of relatively old buildings. The buildings were built with different technologies. Very often only locally available material was used. In many cases, the properties of old materials are not available in the literature. However, it is necessary to know the thermal properties of building materials for the preparation of a reconstruction design. Thermal properties of materials are the basis for determination of heat losses of buildings useful for design of heating systems. The aim of this paper is to compare the research results focused on the thermal conductivity of different old construction materials (stones and rocks) and to show examples of preserved historical agricultural buildings. The results presented in this paper are based on the measurements by the portable instrument Isomet 2104. Authors recognised significant differences between tested materials. The mean values of thermal conductivity λm of tested materials: gaize 1.49 W m-1 K-1, artificial marble 1.80 W m-1 K-1, gneiss 2.36 W m-1 K-1, proterozoic shale 2.68 W m-1 K-1, granite 3.66 W m-1 K-1 and quartz sandstone 6.15 W m-1 K-1. Differences between thermal conductivity values of stones and rocks should be respected in calculation of heat balance of new or reconstructed buildings to avoid the problems of the formation of thermal bridges.

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745–750 P. Kic
Influence of air-conditioning on dust level in drivers’ cabin during the harvest of grain
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Influence of air-conditioning on dust level in drivers’ cabin during the harvest of grain

P. Kic

Czech University of Life Sciences Prague, Faculty of Engineering, Department of
Technological Equipment of Buildings, Kamýcká 129, CZ165 21 Prague, Czech Republic
Correspondence: kic@tf.czu.cz

Abstract:

The period of grain harvest is characterized by dry and hot summer weather. During the grain harvest is generated large amount of dust which significantly influences surroundings, but mainly drivers are exposed to dust pollution. The aim of this paper is to present results of microclimatic research focused on dust pollution in drivers’ cabin of tractors and combine harvesters of different construction used for harvest of grain. The machinery selected for this research includes the old but also very modern tractors and combine harvesters which are equipped with air conditioning. In the frame of this research the concentration of air dust was measured by exact instrument DustTRAK II Model 8530 aerosol monitor. Using the special impactors the PM1, PM2.5, PM4, PM10 size fractions were also measured. Obtained results of measurements were evaluated and concentrations of different size of dust particles were analysed. Results of different indoor conditions measured in new and old machinery are generalized.

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700–706 J. Hart, and V. Hartová
The next generation of multiple temperature sensor
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The next generation of multiple temperature sensor

J. Hart¹,* and V. Hartová²

¹ Czech University of Life Sciences Prague (CULS), Faculty of Engineering, Department of Technological Equipment of Buildings, Kamýcká 129, CZ165 21 Prague, Czech Republic
² Czech University of Life Sciences Prague (CULS), Faculty of Engineering, Department of Vehicles and Ground Transport, Kamýcká 129, CZ165 21 Prague, Czech Republic
*Correspondence: janhart77@gmail.com

Abstract:

Long-term and short-term measurements of temperature at different depths in soil have always been very complicated. The solution that was used until now was measuring using soil thermometers. Measurements were done at shallow depths and generally only allowed for measuring of one temperature, and always at the one depth which was determined for the measurement (normally 5, 10, 20, 50, 100, 150 and 300 cm). These problems were relatively limiting and impractical. It was therefore necessary to devise an alternative for a simple and effective solution that would eliminate these disadvantages – it was necessary for a probe to allow temperature to be measured at different depths at one measuring point without having to change its position. A requirement simultaneously arose for the need to be able to measure temperatures at greater depths, and a multiple probe was therefore conceived consisting of a rod for dynamic penetration tests.

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1119–1126 P. Neuberger and P. Kic
The use of unsteady method for determination of thermal conductivity of porous construction materials in real conditions
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The use of unsteady method for determination of thermal conductivity of porous construction materials in real conditions

P. Neuberger¹* and P. Kic²

¹ Czech University of Life Sciences Prague, Faculty of Engineering, Department of Mechanical Engineering, Kamýcká 129, CZ165 21 Prague, Czech Republic
² Czech University of Life Sciences Prague, Faculty of Engineering, Department of Technological Equipment of Buildings, Kamýcká 129, CZ165 21 Prague, Czech Republic
*Correspondence: neuberger@tf.czu.cz

Abstract:

The possibility to determine the thermal conductivity of construction materials outside the laboratory conditions is useful for professional practice mainly for control and inspection activities on real existing buildings. The requirement to determine the thermal conductivity can be useful above all for different thermal insulation materials but for other materials as well, even for compact soils or rocks. This paper describes methods and instrument which can be used for these measurements, as well as the results of measurement of porous building materials. Measurements presented in this paper were carried out by the needle and surface sensor. Four different materials were selected for verification of technical parameters of Isomet 2104. Besides the thermal conductivity there were determined also thermal diffusivity and volume-specific heat capacity of materials. The carried out measurements confirmed the applicability of this device for practical measurements of thermal conductivity in real conditions. For porous materials, there were determined significant differences between the data presented by the manufacturer or in the literature and measured values, in some cases. Differences between the measured values of thermal diffusivity and volume-specific heat capacity of porous materials were always statistically significant. Authors tested different materials including thermal insulation based on agricultural products.

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768–778 M. Hromasová and M. Linda
Analysis of rapid temperature changes
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Analysis of rapid temperature changes

M. Hromasová* and M. Linda

Czech University of Life Sciences in Prague, Faculty of Engineering, Department of Electrical Engineering and Automation, Kamycka 129, CZ165 21 Praha – Suchdol, Czech Republic
*Correspondence: hromasova@tf.czu.cz

Abstract:

 The analysis of rapid temperature changes in the dynamic system is described in the paper. Temperature changes are in range of tens of milliseconds. The sensor we used has a significant influence on the dynamic system. In these cases we need to use thermocouples that have appropriate transfer characteristics and can be manufactured with a low time constant. The time constant directly corresponds with weight and size of the sensor. The quality factor is usually in a range between 0.98 and 0.995. Information about the temperature course is particularly important in the field of dynamic systems, e.g. agricultural machines where the switching components are overloaded by pulse switching of technology systems. For the object analysis we use the thermocouples with diameter 0.012 mm with non-encapsulated finish and 0.12 mm with suppression of interference impact and comparative temperature fluctuation. For the analysis of dynamic temperature changes we conduct a measurement with a load factor change, which is the mean value of power change, expressed as ratio of the pulse duration to the delay between pulses, this way we will affect the measurement conditions. As a solution we use measurement methods for a steady state, an impulse test and a method of local measurement of temperature. Compared to a real principle of a component we do not increase temperature of the environment during experiments. The results of measurement can be applied for design and implementation of switching systems for electronic circuits with signal modulation and power load.

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