Heat-/ventilation engineering. Dimensioning of heating and air-conditioning systems

On the basis of the predetermined PPD (predicted percentage of dissatisfaction) value the air conditioning quantities associated with it are determined, and then the most suitable heating, ventilating or air conditioning system is chosen with which the sought for goal of comfort can be achieved with the least expense of primary energy and with the lowest investment and operating costs. This last step requires extraordinary professional experience and basic knowledge of heating and air conditioning engineering. The discussion covers single development steps of heating, ventilating, and air conditioning engineering; comfort standards; numerical calculation of room air flows; and concluding assessment. Since the demands for comfort differ among people, individual control is required. In this sense it is not unconditionally necessary to guarantee equal climatic conditions at each point in the dwell zone of the enclosed room. Methods are described that give the opportunity to calculate at any point of the enclosed room the values of the air temperature, air motion, relative humidity, and pollutant concentration.