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 ...
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 ...
