Relationship between Energy Efficiency Coefficient and Energy Difference

D. IVANOV

Institute of Agricultural Mechanization and Electrification, BG-1080 Sofia, Bulgaria

Abstract

IVANOV, D., 2000. Relationship between energy efficiency coefficient and energy difference. Bulg. J.Agric. Sci., 6: 605-608

The term energy balance, used in the present study, means the difference between the energy obtained from grain crops and the energy inputs in production per area unit, production unit, respectively. The energy efficiency coefficient is an undimensional physical quantity and does not give a visible expression of the absolute value of either energy returns or energy expenditures. Literature, studied by the author, does not provide a definition of the concept energy balance. Both energy efficiency coefficient and the concept of energy difference, introduced by the author, basically reflect the rate of sun energy assimilation by grain crops, but the second one reflects the quantity of assimilated sun energy in absolute physical dimension (MJ/ha; MJ/kg). Another convenience of this concept is that the thus obtained energy difference can be compared to other energy equivalents, grain produce of different crops, food products, unrecoverable energy resources such as coal, petroleum products, natural gas, etc.
There is a definite similarity between the purely economic concept of balance and the above-formulated concept of energy balance. The economic concept of balance means equality of assets and liabilities, the profit (loss) of a certain activity being included in the respective part of the balance. In principle, the concept of energy balance also means equality between energy returns and energy expenditures, the positive (negative) energy difference being included in the respective portion of the equation as well.
By definition, in case of using the economic concept of balance, when the energy difference is a positive quantity, there is energy profit from grain production and when negative – it has suffered energy loss.

Key words: energy balance, energy difference, energy efficiency, unit of production