Energy-saving parameters of greenhouses for small businesses

Approximately 95% of the total heat losses of a greenhouse for year-round use are losses through translucent enclosing structures. Therefore, to reduce energy costs, the area of the enclosing structures of the cultivation structure should be minimal. The purpose of the study included the derivation of formulas to substantiate the energy-saving space-planning parameters of greenhouses offered by the market for farms, and a comparative assessment of various types of structures. Formulas were obtained for determining the minimum fencing factor for greenhouses of various shapes, on the basis of which they were compared in terms of heat losses and material consumption for enclosing structures

A continuous DC voltage control function for meshed HVDC grids, and the impact of the underlying future AC grid due to renewable in-feed

This paper discusses the development of a continuous high voltage direct current (HVDC) voltage control function for future meshed HVDC grids. Starting from a state-of-the-art discontinuous voltage droop control, which is used in point-to-point links, a continuously differentiable control function is developed. Using a mathematical description, the control function is transformed to meet the HVDC voltage control strategy for meshed HVDC grids. The control function's stability is discussed and its robustness is shown on an example. The example discusses and compares the current and future characteristics of the underlying AC transmission grid and the impact renewable in-feed has to the control function