Холодильная техника и кондиционирование
An algorithm of calculation of vacuum-evaporating installations for the production of iceslurry by spraying water. The calculation algorithm consists of 5 blocks:source data, heat and material balance, water vapor vacuum system and the description of the atomization process; process of drops crystallization; determination of the geometric parameters of the tank-crystallizer. The calculations are made according to the developed algorithm; the results are presented in form of graphs. Analyze the following parameters: influence of drop diameter on time complete freeze; influence of drop diameter on the height of the crystallization zone and the radius of the tank- crystallizer; influence of the fluidized bed porosity at a deposition rate of droplets in different diameter; influence of the mass fraction of ice in ice slurryon pumping speed of water vapor at different thermal capacity.
The influence of the skin thermal conductivity of the patient on his heat condition during and after procedure of whole body gas cryotherapy (WBGC) has been examined. Heat transfer in human body was characterized within the bounds of 19-compartment Gordon model for a “standard” human being which was modified purposely with due regard for individual anthropometric data as stature, body weight, relative adipose and muscular tissue and others. Computation of heat-transfer coefficients of cylindrical compartments was realized according to inquiry formulas. Results of experimental investigations of difference of temperature of cutaneous coverings of young (21 years old) and high aged (69 years old) sportsmen after WBGC procedure in comparison with the results of computing experiment are presented. It has been revealed that measured and calculated skin temperatures for two age groups differ less than 0,2 °С and difference between skin temperature of abdomen compartment of young and high aged patients was 4 °С at the temperature of gas cooling medium (air) minus 110 °С and 3 minutes of WBGC time exposure. We concluded that in wide-ranging possible relative age-related changes of basal metabolic rate, thickness of hypoderm and thermal conduction of skin, exactly thermal conduction changing brings in capital contribution of difference of temperature of cutaneous covering of young and high aged patients.
We consider the specific heat-shielding characteristic of a building, as a measure of its thermal protective shell. For determine of calculation value of specific heat consumption for building heating during heating season, you need to know thermal and geometric properties of fencing structures of building and conditions of their functioning in depend on climatic conditions of region, where the building is situated. The field investigations were made. The thermal and geometric properties have been identified. This allowed to do required calculations on determination of specific heat consumption for building heating during heating season. It was made comparison of the results with normative documents. All provisions are accompanied by examples.
The article deals with optimization methods of thermal processes in life-support systems which service objects of different functional purposes, using mathematical modeling based on thermodynamic model of Professor A.A. Rymkevich. When creating a mathematical model uses simulation modeling, the essence of which lies in the fact that the process of functioning of a complex system is represented as an algorithm, which is implemented on a computer. The ways of solving the optimization problem is: the use of various air handling schemes (supply and exhaust direct-flow air handling, with recirculation air and heat recovery), energy-efficient equipment with (EC-motors), as well as day/night and summer/winter modes in the operation of heating, ventilation and air-conditioning systems. The use of recirculation air in ventilation systems is alternative way of saving with which you can re-use exhaust air and mixing it with fresh air. Heat recovery helps to reduce energy consumption through the use of emitted heat into the environment of exhaust air. The variants of the optimization criterion were presented by which it is possible to give a quantitative and qualitative assessment of the optimized life-support system.