Controllability of cross-flow heat exchangers

Controllability of cross-flow two-phase heat exchangers

“…However, for normal operating conditions, as described in section 6, the condition number of the controllability matrix, i.e. the ratio of the largest to smallest singular values, is 8.442 Â 10 9 which shows that large values of the control input are required to control this heat exchanger [2].…”

“…Since the compressor and the expansion device have much faster reactions than the heat exchangers [1], they can be modeled using algebraic equations. Controllability of single-phase cross-flow heat exchangers has been analyzed in the past [2], this paper addresses the controllability of cross-flow heat exchangers operating under two-phase flow conditions. Since the high-pressure side of the vapor compression cycle can have a condenser or a gas cooler, for which there is no two-phase flow, we will consider only the evaporator in our analysis since this component always operates in two-phase.…”

Heat Exchange with the Surfaces of Envelope Structures of Flat and Cylindrical Shapes

“…Найбільш істо-тне значення при теплообміні між поверхнею ого-роджуючої конструкції і повітряним середовищем приміщення теплового споживача має передача тепла конвекцією і випромінюванням, причому коефіцієнт тепловіддачі визначається як сумарна величина випромінювання і конвекції [2].…”

Delay-independent sliding mode control for a class of quasi-linear parabolic distributed parameter systems with time-varying delay

“…After discretization, many existing theories and techniques are available for lumped parameter systems. However, the order of the resulting system must be sufficiently high to obtain an acceptable accuracy [12,13]. The control performance using such approximate techniques can be limited if the approximate model is inaccurate due to a too low order.…”