Assessment of effectiveness of HET system for soil temperature stabilization.

2021 ◽  
Vol XXIV (5) ◽  
Author(s):  
Alexey A. Ishkov ◽  
Anatoly A. Gubarkov ◽  
Gennady V. Anikin

The construction of buildings and structures in the zones of distribution of frozen soils follows the principle I. The bearing capacity of frozen soils significantly depends on their value of negative temperature. When thawed, such soils shrink, which negatively affects the objects built on them. To prevent this, temperature stabilization systems for frozen soils are used. Simultaneous accounting of the thermal effect on the frozen soil of an engineering object, as well as the temperature stabilization system of soils, is a difficult task, the accuracy of determining the strength characteristics of the soil will depend on the correctness of its solution. This paper presents calculations of the temperature fields of frozen soils with simultaneous exposure to an object with intense heat (RVS with hot oil) and soil temperature stabilization system of the horizontal natural-acting tubular system (GET) type. The calculations follow the previously developed mathematical model of the temperature stabilization system with a horizontal evaporator. The authors consider the efficiency of the operation of the GET system charged with different refrigerants (ammonia and carbon dioxide) for different geocryological subzones of Western Siberia. Particular attention should be paid to the fact that the soil was initially at a close to positive temperature (−0,1 °C), but after calculating for 10 years, the entire soil mass around the evaporation part of the temperature stabilization system froze because of the soil temperature stabilization system. Systems charged with carbon dioxide showed better work efficiency. This is due to two factors: a lower value of the lower critical heat load, which gives more working days per year relative to the system charged with ammonia; and the evaporative part of the system on carbon dioxide, which has the average temperature 1 °C lower than ammonia systems. The results show that carbon dioxide as the heat carrier for the GET system is the most effective.


Author(s):  
Lucas Costa Victoria ◽  
Igor Vaz ◽  
Luiz Alberto Oliveira Rocha ◽  
Elizaldo dos Santos ◽  
Michel Kepes Rodrigues ◽  
...  

Author(s):  
B.K. Cameron

THE PROPERTY to be discussed is a mixed sheep and cropping unit, situated ei ht a miles east of Ashburton and midway between the Ra aia and the Ashburton rivers. Average annual rainfall is 27 in., evenly spread, but there is very high summer evaporation and therefore frequent droughts. On average, the soil is below wilting point for 40 to 50 days each summer. Winters are cold with the soil temperature being below 48°F for about four months each year. The soil is a Lismore stony silt loam averaging 9 in. in depth over gravel.


2013 ◽  
Vol 27 (4) ◽  
pp. 359-367 ◽  
Author(s):  
T. Adak ◽  
N.V.K. Chakravarty

Abstract Temporal changes in surface soil temperature were studied in winter crop. Significant changes in bare and cropped soil temperature were revealed. Air temperature showed a statistically positive and strong relationship (R2 = 0.79** to 0.92**) with the soil temperature both at morning and afternoon hours. Linear regression analysis indicated that each unit increase in ambient temperature would lead to increase in minimum and maximum soil temperatures by 1.04 and 1.02 degree, respectively. Statistically positive correlation was revealed among biophysical variables with the cumulative surface soil temperature. Linear and non-linear regression analysis indicated 62-69, 72-86 and 72-80% variation in Leaf area index, dry matter production and heat use efficiency in Indian mustard crop as a function of soil degree days. Below 60% variation in yield in Indian mustard was revealed as a function of soil temperature. In contrast, non-significant relationship between oil content and soil temperature was found, which suggests that oil accumulation in oilseed crops was not affected significantly by the soil temperature as an independent variable.


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