The present paper concerns a problem of decisive criteria and their order in formwork selection problem. As the factors affecting the choice of exact form work system have been often discussed in literature, their importance has not been distinctly formulated yet, what hampers aiding formwork selection with MCDA methods that require criteria weights (eg.: SAW, TOPS IS etc.). Therefore, author ran a survey - the decisive criteria were recognized and verified within polls send to various contractors. An analysis of survey results including criteria ordering is a subject of the present elaboration.
In the paper a research on cost-effective optimum design boiling temperature for Organic Rankine Cycle utilizing low-temperature heat sources is presented. The ratio of the heat exchanger area of the boiler to the power output is used as the objective function. Analytical relations for heat transfer area as well power of the cycle are formulated. Evaporation temperature and inlet temperature of the heat source medium as well its mass flow rate are varied in the optimization method. The optimization is carried out for three working fluids, i.e. R 134a, water and ethanol. The objective function (economics profitability, thermodynamic efficiency) leads to different optimal working conditions in terms of evaporating temperature. Maximum power generation in the near-critical conditions of subcritical ORC is the highest. The choice of the working fluid can greatly affect the objective function which is a measure of power plant cost. Ethanol exhibits a minimum objective function but not necessarily the maximum cycle efficiency.