This paper presents results of the verification of a heat exchanger composed of gravitation thermal pipes installed in a broiler chicken feeding facility. The objective of the study was to verify the possibility of the application of a power management system including a heat recovery system in a heavy-duty environment of a broiler chicken fattening facility and to specify effects of the system upon the specific consumption of energy for space heating and ventilation of the animal house. The calculation of the thermal balance of the animal house documents that the power management system that includes a heat recovery exchanger unit may reduce the thermal capacity of external sources of heat in the animal house by 26.5% even when subject to extreme conditions and at the atmospheric temperature of -12°C and the age of chickens being 1 day. The results of the metering and calculations of the efficiency have proven that the heat exchanger reaches the operational efficiency of 10–47% and thermal efficiency of 20–80% even during the most demanding operational first twenty days of the breeding cycle of broiler chickens. The specific consumption of energy for space heating and ventilation related to 1 kg of the live weight of ...
The paper deals with assessment of thermal fields and temperature changesin ground massif with horizontal heat exchanger used as a heat source for a heatpump. Temperatures in the zone of the horizontal ground exchanger are comparedwith temperatures in a reference land. Changes of heat potential of the soil duringthe heating period are also assessed. Possibilities of recovery of thermal potentialof the ground massif when utilizing vertical and horizontal exchangers are analyzedin the opening part of the paper. The results of the first verification indicatedthat average temperatures in the horizontal planes of the ground massif did not differconsiderably with distance from the exchanger tube. Differences in averagetemperatures in reference and experimental lands confirmed sufficient heat potentialof the ground massif even at the peak of the heating period. The differences inaverage temperatures reached up to 6.51 K in the end of the heating period whileat the beginning of the heating period, the differences in average temperaturesdropped to 1.35 K. The differences between maximum and minimum temperaturesin the zone of the ground exchanger reached up to 1.9 K at the peak of the heatingperiod and rose to 3.9 K at the beginning and end of the heating period. The firstresults of our measurements ...
The article presents results of modeling and operational evaluation of specific energy consumption in four pig breeding categories, which have been realized under the project QF 3200 „Expert System for Determination Support and Optimization of Technology Processes Control in Agricultural Production“ supported by Czech Ministry of Agriculture. The first step of solution brought mathematical equations that describe physical relation of specific energy consumption to machine input, technology cycle duration, total efficiency and day time operation. As example of energy requirements of material manipulation during feeding operation, mulch treatment are presented in equations 1 to 4. Following performed analysis based on calculated and operationally proved energy consumptions were created simple mathematical equations (tab. I) that qualify relation of specific energy consumption Q [Wh∙d-1∙ks-1] to recommended or standardized values of dry pasture mkr [kg∙d-1∙ks-1], wet pasture mkr,v [kg∙d-1∙ks-1], specific mulch production mmr [kg∙d-1∙ks-1], liquid manure mk [kg∙d-1∙ks-1], stable area S1,u [m2∙ks-1], disinfected area S1,z [m2∙ks-1], technology cycle duration τTC [d] and average animal weight mz [kg-1∙ks-1]. The elementary mathematical models come out from hypothesis that individual operation and technology cycles of agricultural production is possible to optimize on the base of theoretical knowledge adjusted by real ...
The behaviour of carob (Ceratonia siliqua L.) powder relevant to its densification at low pressure was determined given different equipment aspect ratios (0.5, 1.0 and 1.5) and varying rates of deformation (5.5, 10 and 14.5 mm min-1). The effects of both parameters were examined through the analysis of variance and trends were fitted to observed mechanical responses using standard regression technique. Both aspect ratio and the time rate of deformation had highly significant effects on the material's response to load. Strain rate and specific power requirement were power functions of the equipment's aspect ratio, at all rates of deformation. These findings furnish insights on mechanical response in compressed food powders which are applicable in modelling related food handling and processing systems. ...
Bulk, porous oil-bearing materials acquire various degrees of densification under varying influences of equipment and process parameters with direct bearings on yield during compressive abstraction of oil from such materials. Effects of both aspect ratio and compression cycle on the course of densification were investigated. Mechanical response and oil expression indices were analysed for variances and treatment means were compared using Duncan's multiple range test. All influence factors had significant effects on mechanical response and oil yield. Significant improvements in achievable deformation and specific energy demand were obtained through repeated induction of compressive stress; compression cycle correlated positively with both deformation and energy demand. Margin for the expenditure of energy became wider as pressure ratio at the oil point became lower. This study reveals that performance of compression schemes may be significantly enhanced through careful application of the pressure ratio. ...
The paper analyses the leakage of air-to-air recovery heat exchanger consisting of 100 capillary thermal tubes 1.5 m long and aligned in ten rows. The operation of the recovery exchanger prototype was tested in a pigsty. The analysis focuses on how the exchanger leakage affects the heat utilisation efficiency of the air ducted from the pigsty, changes in supply/exhaust air flow rate ratio, supply air temperature, thermal output obtained, and exchanger’s total thermal and mass balances. The results obtained in in-process measurements and the mass and thermal balances show that the exchange leakage causes the outside supply air to contain 12.1–37.3% of the pigsty exhaust air. The percentage of the pigsty air increases with the increase of mass flow rates of supply and exhaust air. This leakage resulted particularly in a major change in supply and exhaust air mass flow rates, higher moisture content, temperature and thermal flow of the air conducted in the pigsty. The change in air flow rates resulted in ventilation change so that the overpressure ventilation took place instead of balanced ventilation. This change led to increased thermal losses by air penetrating through leaks in the peripheral building structures. Increased supply air moisture content made it ...
In the technical field the energy balances are derived from the 1st thermodynamic law, which covers merely the instantaneous quantitative aspects of heat flows. In terms of energy conservation law these balances are expressed in the form of constant sums of exergy and anergy. And that is why they cannot, or can only to a very limited extent, be used to define the transformation of part of the energy (exergy) to the less valuable energy (anergy). Using the 2nd thermodynamic law we have a chance to trace the energy transformation through entropy, a quality indicator of every heat process and an accompanying symptom of process irreversibility. The plate air-to-air heat exchanger, whose exergy analysis is in the spotlight of our interest, operates, in terms of the laws above, in irreversible changes, while the change of entropy induced by the heat flows depends on the construction and surface of the heat exchange areas. The article analyses the influence of air inlet temperatures on the thermal exergy efficiencies of the heat exchanger and the heat loss exergy. Assessment is based on extensive measurements of the temperature, humidity and flow rate of the heated and cooled air in the plate heat exchanger. Both ...
