CFD Model of Regenerative Heat Exchanger

This paper is focused on the Computational fluid dynamics (CFD) modeling of regenerative heat exchanger suitable for animal houses. Buildings used for housing of animals in farms with intensive breeding, like poultry or pig houses, are characterized by high generation of heat inside, partly produced by animals, and in the case of small young animals, supplemented also by heating. On the other side these buildings need intensive ventilation which causes big losses of energy by exhausted air. A good way how to reduce heat losses can be the use of technical systems of heat recovery. There are two principal constructions of heat exchangers for heat recovery. There are either recuperative or regenerative heat exchangers. Industrially produced heat exchangers, commonly used in residential or industrial buildings, can be used in agricultural conditions only with difficulties, mainly because of the high dust concentration, which is extremely high in animal houses. The methods of CFD modeling were used to calculate main parameters of special heat exchanger, developed for application in animal houses. The construction of regenerative heat exchanger with fixed matrix is based on heat accumulation in material of matrix in the form of massive plates. The program Fluent was used for airflow and heat exchange simulations. Results of simulations were verified by measurement of prototype of real heat exchanger

Mathematical Model for Optimal Arrangement of Milking Parlor

Milking is a key operation on dairy farms. The capacity and function of milking parlor influences production conditions (time of operations, needs of labor, total costs), so actually it affects the efficiency of the whole dairy farm. This paper presents a structure and principal parts of mathematical model which was created with the aim to enable to farmers and designers to choose suitable type of milking parlor for specific farm conditions. Three principal questions important for optimization of milking parlor are: technical parameters, indicators of labor productivity and economic criteria. The model structure was created with the aim to find the answer to all of them. The model includes in calculation main parameters of typical arrangements of milking parlors used in modern dairy farms. The inputs are primarily parameters of a dairy farm like a capacity, number of milking per day, available time for milking process in the farm and others. There is a proposed number of milking stalls with the level of automation, number of operators, costs of labor, etc. The optimization is based on the evaluation of all partial results, which are compared in terms of needs of time, labor and specific costs, calculated successively for different proposed milking parlors. This model was verified mainly with some results from measurements in the Czech large scale farms with different technical levels of milking parlors. It can be easily adapted to changed conditions, due to new generations of milking parlors with more modern equipment and facilities or for different production and economic situation.

Analysis of Management, Labor and Economics of Milking Systems in Intensive Goat Farms

Dairy goat farms are growing in the world, but their technological level and, particularly, milking equipment are less developed than those of dairy cow farms. This study aims to evaluate milking parlors in the current situation in modern goat farms and suggest possible solutions or improvements. Ten goat farms located in various municipalities of the Friuli-Venezia Giulia region (Northeast Italy) adopting different milking systems (parallel milking parlors, milking carts, and milking buckets) were monitored. The mathematical model developed originally for the evaluation of milking parlors for dairy cows was modified and adapted to goat milking systems. Time for milking and final specific direct costs are the main parameters that enable evaluation and choice of suitable milking parlor; neglect or promotion of only one of the mentioned criteria may lead to an uneconomic investment or impaired operation of a farm. The research results showed that the modern milking systems, with a greater number of stalls and milking clusters, have a greater capacity and require less time for milking a goat than bucket and cart systems. The study also demonstrated that increasing the capacity of dairy goat farms enables a reduction of the final specific costs for milking

Applying a Mathematical Model to Compare, Choose, and Optimize the Management and Economics of Milking Parlors in Dairy Farms

Dairy farms are growing in several areas of theworld,with consequent need for amodernization of milking equipment. The objective of this research is to evaluate milking parlors in current and future situations in modern farms. Several Italian farms were studied: three farms with side-by-side milking parlors (50 cows, 82 cows, and 100 cows), two with herringbone milking parlors (70 cows and 90 cows) and two with rotary milking parlors (360 cows and 900 cows). The choosing and evaluation of milking parlor parameters is based on results of previous research, using the mathematical model developed in the Czech University. The time for milking and the final specific direct costs are the main parameters which enable evaluation and choosing of suitable milking parlor from the dairy; neglect or promotion of only one of the mentioned criteria may lead to uneconomic investment or impaired operation of a farm. The evaluation of existing milking parlors can help to enhance the milking process and operations from the point of view of either technical improvement or improved activity of milkers. The results of measurement and calculation in current farms are compared with possible future enlarged farms. The study demonstrated that increasing the capacity of dairy farms enables a reduction of the final specific direct costs for milking

Animal housing in hot climates : a multidisciplinary view

Since energy balance, thermoregulation and environmental aspects of "high producingdairy cows" were thoroughly studied (Brody, 1945; Flatt et al., 1969; Berman et al., 1985),the high producing dairy cow more than doubled production with a body weight increase of about 10-20% which imposed a three fold increase of heat increment (Kadzer et al., 2002).There is an apparent world wide lack of realization that changes in the physical and geneticconstitution of cows may have affected their thermoregulatory capability in hot climate forexample, blood plasma fluctuation in volume and constituents (Maltz et al, 1994); as wellas how they cope with heat stress (Kadzer et al., 2002). As a result, research inthermoregulation in relation to housing facilities and cooling management falls behind(except for few exceptions seen below) the aggressive selection for increased productionthat livestock undergoes as well as changes in technology and housing materials. Therefore,most of the improvements in this area are farmers and designers initiatives based oncommon sense and experience.peer-reviewe

A Century of Use of SOLOMIT Thermal Insulation Panels

This article traces the century-old history of using a thermal and acoustic insulation panel called SOLOMIT. It presents some of Sergei Nicolajewitsch Tchayeff’s patents, on the basis of which production and installation took place. The survey section provides examples of the use of this building component in Australia, Czechoslovakia, France, Germany, the Netherlands, Poland, Russia, the Soviet Union and Spain. It pays attention to applications in the 1950s and 1960s in collectivized agriculture in Czechoslovakia. It also presents the results of measuring the thermal conductivity of a panel sample, which was obtained during the reconstruction of a cottage built in the 1950s and 1960s of the 20th century. Even today, SOLOMIT finds its application all over the world, mainly due to its thermal insulation and acoustic properties and other features, such as low maintenance requirements, attractive appearance and structure and cost-effectiveness

Analysis of principal stress factors affecting drivers in different vehicles

The aim of this research paper is to compare the effect of the heart rate variabilities on different vehicle drivers. The most common urban transport vehicles (bus, tram and metro) are compared with typical mobile agricultural machines (tractors and combine harvesters) and passenger car. The measurements were focused on the complexity and traffic routes, velocities of each vehicle and ages of drivers related to changes in the heart rate of drivers as main parameters. The authors characterize cardinal factors affecting the contentment of drivers while undertaking their performance. The results of the measurements showed that the lowest mean heart rate value was registered on metro (subway car) drivers scoring 59 bpm, whereas the bus drivers 80 bpm and tram 77 bpm. The mean heart rate value of the combine harvester drivers scored 106 bpm and tractor drivers 108 bpm, which indicates that the driver’s heart rate of the agricultural machineries were significantly greater. The heart rate of tram drivers has increased significantly in a short period of time by 75%, metro (subway) drivers by 59%, combine harvester drivers by 23% and tractor drivers by 19%, whereas the passenger car drivers’ heart rate value increase was by 30%. The driving velocity, drivers’ age and weight showed its effect on the heart rate variabilities. The data collections were made by a heart rate measurement device. Relevant data on technical conditions stretch and shape design routes; as well as the heart rate variabilities on the respective drivers are collected carefully for detail statistical analysis

ENGINEERING FOR RURAL DEVELOPMENT IMPROVEMENT OF MOBILE MILKING PARLOURS IN SMALL DAIRY FARMS INCLUDING TECHNICAL AND FUNCTIONAL ASPECTS

Abstract. The aim of this paper was to show and analyse selected technical parameters of mobile milking parlours, which could help in solving the problem of milking on some dairy farms. The article was based on the experience of operating a specific dairy farm in Poland, intended for 28 cows and using a mobile milking technique. The measured consumption of fuel by the tractor used to operate the mobile milking parlour in the investigated dairy farm was (mean±SD) 2.6±0.4 kg⋅h -1 for morning and evening milking. Given the measured milking time, cow herd size and milk yield, it was possible to calculate the fuel consumption, which amounted to 0.11±0.003 kg⋅cow -1 ⋅milking -1 and 8.44±1.3 kg⋅t -1 (kg of diesel fuel per ton of milk). The cost of diesel fuel was about 1.16 EUR⋅kg -1 , so the cost of the fuel consumed by the tractor was about 0.13±0.004 EUR⋅cow -1 ⋅milking -1 . In order to extend the research analyses, model calculations were used, based on the methodology applied in evaluation as well as optimization of parlours, created in the Czech Republic. The results of measurements and calculations in the subject farm were compared against possible future technological improvements and a farm with enlarged capacity of 50 cows. The process of evaluation of the milking parlour parameters was based on the available information and results of previous research conducted in Polish dairy farms in recent years. The time spent on milking and the final specific direct costs are the main parameters, which enable the evaluation and selection of a suitable milking parlour for a dairy farm

ENGINEERING FOR RURAL DEVELOPMENT NEW METHODS IN EDUCATION OF HVAC FOR ERABEE

Abstract. The paper describes the new approach to the education of the course focused on heating, ventilation and air-conditioning in the frame of MSc. study programs specialized on Agricultural and Biosystems Engineering. Special attention is paid to the new methods of individual study with e-learning, modern methods of designing with use of specialized and also commercial software and programs (e.g. CFD Fluent, OpenFOAM etc.). Seminars and laboratory work complete the education with practical or experimental measurements of all main microclimatic parameters (thermal state, purity of air, noise, illumination etc.) and individual designs prepared by the students during the semester and presented by the students in seminars of the group at the end of semester, before the examination period. Lectures and seminars cover all principal problems related to the buildings and equipment in agriculture and Biosystems engineering